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1.  Socio-demographic and lifestyle factors associated with overweight in a representative sample of 11-15 year olds in France: Results from the WHO-Collaborative Health Behaviour in School-aged Children (HBSC) cross-sectional study 
BMC Public Health  2011;11:442.
Background
The prevalence of overweight in children and adolescents is high and overweight is associated with poor health outcomes over short- and long-term. Lifestyle factors can interact to influence overweight. Comprehensive studies linking overweight concomitantly with several demographic and potentially-modifiable lifestyle factors and health-risk behaviours are limited in adolescents - an age-group characterized by changes in lifestyle behaviours and high prevalence of overweight. Thus, the objective of the current study was to examine the association of overweight with several socio-demographic and lifestyle variables simultaneously in a representative sample of adolescents.
Methods
A nationally representative sample of 11-15 year-olds (n = 7154) in France participated as part of the WHO-Collaborative Health Behaviour in School-aged Children (HBSC) study. Students reported data on their age, height, weight, socio-demographic variables, lifestyle factors including nutrition practices, physical activity at two levels of intensity (moderate and vigorous), sedentary behaviours, as well as smoking and alcohol consumption patterns using standardized HBSC protocols. Overweight (including obesity) was defined using the IOTF reference. The multivariate association of overweight with several socio-demographic and lifestyle factors was examined with logistic regression models.
Results
The adjusted odds ratios for the association with overweight were: 1.80 (95% CI: 1.37-2.36) for low family affluence; 0.73 (0.60-0.88) for eating breakfast daily; 0.69 (0.56-0.84) for moderate to vigorous physical activity (MVPA); and 0.71 (0.59-0.86) for vigorous physical activity (VPA). Significant interactions between age and gender as well as television (TV) viewing and gender were noted: for boys, overweight was not associated with age or TV viewing; in contrast, for girls overweight correlated negatively with age and positively with TV viewing. Fruit and vegetable intake, computer and video-games use, smoking and alcohol consumption were not associated with overweight.
Conclusions
In multivariate model, family affluence, breakfast consumption and moderate to vigorous as well as vigorous physical activity were negatively associated with overweight. These findings extend previous research to a setting where multiple risk and protective factors were simultaneously examined and highlight the importance of multi-faceted approaches promoting physical activity and healthy food choices such as breakfast consumption for overweight prevention in adolescents.
doi:10.1186/1471-2458-11-442
PMCID: PMC3123212  PMID: 21649892
overweight; adolescence; socio-economic status; diet; physical activity and sedentary behavior; smoking; alcohol consumption
2.  Physical activity, sedentary behaviors and dietary habits among Saudi adolescents relative to age, gender and region 
Background
Few lifestyle factors have been simultaneously studied and reported for Saudi adolescents. Therefore, the purpose of the present study was to report on the prevalence of physical activity, sedentary behaviors and dietary habits among Saudi adolescents and to examine the interrelationships among these factors using representative samples drawn from three major cities in Saudi Arabia.
Methods
This school-based cross-sectional study was conducted during the years 2009-2010 in three cities: Al-Khobar, Jeddah and Riyadh. The participants were 2908 secondary-school males (1401) and females (1507) aged 14-19 years, randomly selected using a multistage stratified sampling technique. Measurements included weight, height, sedentary behaviors (TV viewing, playing video games and computer use), physical activity using a validated questionnaire and dietary habits.
Results
A very high proportion (84% for males and 91.2% for females) of Saudi adolescents spent more than 2 hours on screen time daily and almost half of the males and three-quarters of the females did not meet daily physical activity guidelines. The majority of adolescents did not have a daily intake of breakfast, fruit, vegetables and milk. Females were significantly (p < 0.05) more sedentary, much less physically active, especially with vigorous physical activity, and there were fewer days per week when they consumed breakfast, fruit, milk and diary products, sugar-sweetened drinks, fast foods and energy drinks than did males. However, the females' intake of French fries and potato chips, cakes and donuts, and candy and chocolate was significantly (p < 0.05) higher than the males'. Screen time was significantly (p < 0.05) correlated inversely with the intake of breakfast, vegetables and fruit. Physical activity had a significant (p < 0.05) positive relationship with fruit and vegetable intake but not with sedentary behaviors.
Conclusions
The high prevalence of sedentary behaviors, physical inactivity and unhealthy dietary habits among Saudi adolescents is a major public health concern. There is an urgent need for national policy promoting active living and healthy eating and reducing sedentary behaviors among children and adolescents in Saudi Arabia.
doi:10.1186/1479-5868-8-140
PMCID: PMC3339333  PMID: 22188825
Physical activity; sedentary behaviors; dietary habits; lifestyle factors; adolescents; Saudi Arabia
3.  Active play and screen time in US children aged 4 to 11 years in relation to sociodemographic and weight status characteristics: a nationally representative cross-sectional analysis 
BMC Public Health  2008;8:366.
Background
The high prevalence of childhood obesity underscores the importance of monitoring population trends in children's activity and screen time, and describing associations with child age, gender, race/ethnicity, and weight status. Our objective was to estimate the proportion of young children in the US who have low levels of active play or high levels of screen time, or who have both these behaviors, and to describe associations with age, gender, race/ethnicity, and weight status.
Methods
We analyzed data collected during the National Health and Nutrition Examination Surveys 2001–2004, a US nationally representative cross-sectional study. We studied 2964 children aged 4.00 to 11.99 years. Our main outcomes were reported weekly times that the child played or exercised hard enough to sweat or breathe hard (active play), daily hours the child watched television/videos, used computers, or played computer games (screen time), and the combination of low active play and high screen time. Low active play was defined as active play 6 times or less per week. High screen time was defined as more than 2 hours per day. We accounted for the complex survey design in analyses and report proportions and 95% confidence intervals. We used Wald Chi-square to test for differences between proportions. To identify factors associated with low active play and high screen time, we used multivariate logistic regression.
Results
Of US children aged 4 to 11 years, 37.3% (95% confidence interval, 34.1% to 40.4%) had low levels of active play, 65.0% (95% CI, 61.4% to 68.5%) had high screen time, and 26.3% (95% CI, 23.8% to 28.9%) had both these behaviors. Characteristics associated with a higher probability of simultaneously having low active play and high screen time were older age, female gender, non-Hispanic black race/ethnicity, and having a BMI-for-age ≥95th percentile of the CDC growth reference.
Conclusion
Many young children in the US are reported to have physical activity and screen time behaviors that are inconsistent with recommendations for healthy pediatric development. Children who are overweight, approaching adolescence, girls, and non-Hispanic blacks may benefit most from public health policies and programs aimed at these behaviors.
doi:10.1186/1471-2458-8-366
PMCID: PMC2605460  PMID: 18945351
4.  Correlates of video games playing among adolescents in an Islamic country 
BMC Public Health  2010;10:286.
Background
No study has ever explored the prevalence and correlates of video game playing among children in the Islamic Republic of Iran. This study describes patterns and correlates of excessive video game use in a random sample of middle-school students in Iran. Specifically, we examine the relationship between video game playing and psychological well-being, aggressive behaviors, and adolescents' perceived threat of video-computer game playing.
Methods
This cross-sectional study was performed with a random sample of 444 adolescents recruited from eight middle schools. A self-administered, anonymous questionnaire covered socio-demographics, video gaming behaviors, mental health status, self-reported aggressive behaviors, and perceived side effects of video game playing.
Results
Overall, participants spent an average of 6.3 hours per week playing video games. Moreover, 47% of participants reported that they had played one or more intensely violent games. Non-gamers reported suffering poorer mental health compared to excessive gamers. Both non-gamers and excessive gamers overall reported suffering poorer mental health compared to low or moderate players. Participants who initiated gaming at younger ages were more likely to score poorer in mental health measures. Participants' self-reported aggressive behaviors were associated with length of gaming. Boys, but not girls, who reported playing video games excessively showed more aggressive behaviors. A multiple binary logistic regression shows that when controlling for other variables, older students, those who perceived less serious side effects of video gaming, and those who have personal computers, were more likely to report that they had played video games excessively.
Conclusion
Our data show a curvilinear relationship between video game playing and mental health outcomes, with "moderate" gamers faring best and "excessive" gamers showing mild increases in problematic behaviors. Interestingly, "non-gamers" clearly show the worst outcomes. Therefore, both children and parents of non-game players should be updated about the positive impact of moderate video gaming. Educational interventions should also be designed to educate adolescents and their parents of the possible harmful impact of excessive video game playing on their health and psychosocial functioning.
doi:10.1186/1471-2458-10-286
PMCID: PMC2894772  PMID: 20507610
5.  Active gaming in Dutch adolescents: a descriptive study 
Background
Adequate levels of physical activity are part of a healthy lifestyle and in this way linked to better health outcomes. For children and adolescents, the physical activity guideline recommends at least 60 minutes of moderate-to-vigorous physical activity every day. However, many adolescents are not physically active enough and they spend a lot of their time on sedentary activities (such as video games). A new generation of video games that require body movements to play them, so-called "active games", could serve to increase physical activity in adolescents. The activity level while playing these games is comparable to light-to-moderate intensity physical activity. The current study aims to increase our understanding of 1) the demographic characteristics of adolescents who play active games regularly (≥ 1 hour per week) and non-regularly (<; 1 hour per week), 2) time spent on active games, 3) the contribution of active games to daily physical activity and 4) the type and amount of activities being replaced by active gaming.
Methods
A cross-sectional survey was conducted in a Dutch internet panel, questioning adolescents in conjunction with one of their parents. A random sample of 320 households (with stratification on gender of the parent and the adolescent, the age of the adolescent and the region of the household) was selected that owned a console or application for active video games and that had a child aged 12 through 16 years. 201 child–parent couples (63% response) completed an internet survey with questions about demographics, physical activity and sedentary behaviour, and gaming behaviour. The questionnaire also contained questions designed to assess whether and how active gaming replaces other activities. Besides descriptive analyses, independent t-test, Pearson’s chi-square and Mann–Whitney test (when data were not normally distributed) were used for comparisons between regular and non-regular active gamers.
Results
Eleven percent of the adolescents with an active game in their household never used the game. There were no significant differences in gender, education level (of adolescent and parent), ethnicity and sedentary behaviour between regular (n = 65) and non-regular active gamers (n = 114). Adolescents’ (regular and non-regular active gamers) meantime spent on active gaming was 80 (± 136) minutes a week; this potentially amounts to 11% of total physical activity. When time spent on active gaming was included in the calculation of the percentage of adolescents that met the physical activity guideline, the percentage increased significantly (p <; 0.05) from 67 to 73%. According to the adolescents, active gaming mainly replaces sedentary screen time such as TV viewing, internet and non-active gaming. Parental opinions concurred with this appraisal.
Conclusions
The results of this study confirm the idea that active gaming may contribute to an active lifestyle in adolescents, primarily because it potentially contributes substantially to time spent on physical activity. Secondly, active gamers indicate that they spent time on active games which they would have spent otherwise on less active activities.
doi:10.1186/1479-5868-9-118
PMCID: PMC3493303  PMID: 23031076
Active video games; Adolescents; Physical activity behaviour; Physical activity guideline; Sedentary behaviour
6.  Prevalence and factors associated with sedentary behavior in adolescents 
Revista de Saúde Pública  2014;48(2):266-274.
OBJECTIVE
To analyze the prevalence of sedentary behavior and associated factors in adolescents.
METHODS
A cross-sectional study with adolescents aged 10 to 17 years, of both sexes, belonging to a 1994-1999 birth cohort in the city of Cuiabá, MT, Central Western Brazil. Data were collected using a questionnaire containing sociodemographic, economic, lifestyle and anthropometric variables. Sedentary behavior was determined as using television and/or computer/video games for a time greater than or equal to 4 hours/day. Associations with sedentary behavior were evaluated using body mass index in childhood and adolescence and sociodemographic and behavioral variables using hierarchical logistic regression.
RESULTS
The overall prevalence of sedentary behavior was 58.1%. Of the 1,716 adolescents evaluated, 50.7% (n = 870) were male. In multivariate analysis, after adjustment for confounding factors, the variables that remained associated with sedentary behavior were: age (14 and over) (OR = 3.51, 95%CI 2.19;5.60); higher socioeconomic class (OR = 3.83, 95%CI 2.10;7.01), higher level of maternal education (OR = 1.81, 95%CI 1.09;3.01); living in the country (OR = 0.49, 95%CI 0.30;0.81); insufficient physical activity (OR = 1.25, 95%CI 1.02;1.53); experimentation with alcoholic beverages (OR = 1.34, 95%CI 1.08;1.66) and being overweight in adolescence (OR = 1.33, 95%CI 1.06;1.68).
CONCLUSIONS
The high proportion of adolescents in sedentary activities and the lack of association with being overweight in childhood, indicates the need for educational initiatives to reduce multiple risk behaviors. Encouraging physical activity in young people as a way of reducing sedentary behavior and, consequently, being overweight is fundamental.
doi:10.1590/S0034-8910.2014048004635
PMCID: PMC4206135  PMID: 24897048
Adolescent; Sedentary Lifestyle; Life Style; Socioeconomic Factors
7.  Characterizing High School Students Who Play Drinking Games Using Latent Class Analysis 
Addictive behaviors  2013;38(10):2532-2540.
Heavy alcohol use and its associated negative consequences continue to be an important health issue among adolescents. Of particular concern are risky drinking practices such as playing drinking games. Although retrospective accounts indicate that drinking game participation is common among high school students, it has yet to be assessed in current high school students. Utilizing data from high school students who reported current drinking game participation (n = 178), we used latent class analysis to investigate the negative consequences resulting from gaming and examined underlying demographic and alcohol-related behavioral characteristics of students as a function of the resultant classes. Three classes of “gamers” emerged: (1) a “lower-risk” group who had a lower probability of endorsing negative consequences compared to the other groups, (2) a “higher-risk” group who reported that they experienced hangovers and difficulties limiting their drinking, got physically sick, and became rude, obnoxious, or insulting, and (3) a “sexual regret” group who reported that they experienced poor recall and unplanned sexual activity that they later regretted. Although the frequency of participating in drinking games did not differ between these three groups, results indicated that the “lower-risk” group consumed fewer drinks in a typical gaming session compared to the other two groups. The present findings suggest that drinking games are common among high school students, but that mere participation and frequency of play is not necessarily the best indicator of risk. Instead, examination of other constructs such as game-related alcohol consumption, consequences, or psychosocial variables such as impulsivity may be more useful.
doi:10.1016/j.addbeh.2013.04.009
PMCID: PMC3725189  PMID: 23778317
Drinking Games; Alcohol Use; Latent Class Analysis; Adolescents
8.  Video Game Playing Is Independently Associated with Blood Pressure and Lipids in Overweight and Obese Adolescents 
PLoS ONE  2011;6(11):e26643.
Objective
To examine the association between duration and type of screen time (TV, video games, computer time) and blood pressure (BP) and lipids in overweight and obese adolescents.
Design
This is a cross-sectional study of 282 overweight or obese adolescents aged 14–18 years (86 males, 196 females) assessed at baseline prior to beginning a lifestyle intervention study for weight control. Sedentary behaviours, defined as hours per day spent watching TV, playing video games, recreational computer use and total screen time were measured by self-report. We examined the associations between sedentary behaviours and BP and lipids using multiple linear regression.
Results
Seated video gaming was the only sedentary behaviour associated with elevated BP and lipids before and after adjustment for age, sex, pubertal stage, parental education, body mass index (BMI), caloric intake, percent intake in dietary fat, physical activity (PA) duration, and PA intensity. Specifically, video gaming remained positively associated with systolic BP (adjusted r = 0.13, β = 1.1, p<0.05) and total cholesterol/HDL ratio (adjusted r = 0.12, β = 0.14, p<0.05).
Conclusions
Playing video games was the only form of sedentary behaviour that was independently associated with increased BP and lipids. Our findings provide support for reducing time spent playing seated video games as a possible means to promote health and prevent the incidence of cardiovascular disease (CVD) risk factors in this high risk group of overweight and obese adolescents. Future research is needed to first replicate these findings and subsequently aim to elucidate the mechanisms linking seated video gaming and elevated BP and lipids in this high risk population.
Trial Registration
Clinicaltrials.gov NCT00195858
doi:10.1371/journal.pone.0026643
PMCID: PMC3206019  PMID: 22069461
9.  Correlates of weight status among Norwegian 11-year-olds: The HEIA study 
BMC Public Health  2012;12:1053.
Background
The underlying mechanisms of overweight and obesity in adolescents are still not fully understood. The aim of this study was to investigate modifiable and non-modifiable correlates of weight status among 1103 Norwegian 11-year-old adolescents in the HEalth in Adolescents (HEIA) study, including demographic factors such as gender and parental education, and behavioral factors such as intake of sugar-sweetened beverages, snacks and breakfast consumption, watching TV and playing computer games, physical activity and sedentary time.
Methods
Weight and height were measured objectively, body mass index (BMI) was calculated and International Obesity Task Force cut-offs were used to define weight status. Physical activity and sedentary time were measured by accelerometers. Other behavioral correlates and pubertal status were self-reported by questionnaires. Parental education was reported by the parents on the consent form for their child. Associations were investigated using logistic regressions.
Results
There were gender differences in behavioral correlates of weight status but not for weight status itself. Adolescents with parents in the highest education category had a 46% reduced odds of being overweight compared to adolescents with parents in the lowest education category. Adolescents with parents with medium education had 42% lower odds of being overweight than adolescents with parents with the lowest education category. Level of parental education, breakfast consumption and moderate to vigorous physical activity were positively associated with being normal weight, and time watching TV was positively associated with being overweight for the total sample. Gender differences were detected; boys had a doubled risk of being overweight for every additional hour of watching TV per week, while for girls there was no association.
Conclusions
The present study showed a social gradient in weight status in 11-year-olds. Both breakfast consumption and moderate to vigorous physical activity were inversely associated with weight status. No associations were found between intake of sugar-sweetened beverages and snacks, playing computer games and weight status. Watching TV was positively associated with weight status for boys but not for girls. Interventions are needed to gain more insight into the correlates of change in weight status.
doi:10.1186/1471-2458-12-1053
PMCID: PMC3538064  PMID: 23216675
Overweight; Physical activity; Sedentary time; Parental education; Diet; Children; Adolescents
10.  Personal, Social, and Game-Related Correlates of Active and Non-Active Gaming Among Dutch Gaming Adolescents: Survey-Based Multivariable, Multilevel Logistic Regression Analyses 
JMIR Serious Games  2014;2(1):e4.
Background
Playing video games contributes substantially to sedentary behavior in youth. A new generation of video games—active games—seems to be a promising alternative to sedentary games to promote physical activity and reduce sedentary behavior. At this time, little is known about correlates of active and non-active gaming among adolescents.
Objective
The objective of this study was to examine potential personal, social, and game-related correlates of both active and non-active gaming in adolescents.
Methods
A survey assessing game behavior and potential personal, social, and game-related correlates was conducted among adolescents (12-16 years, N=353) recruited via schools. Multivariable, multilevel logistic regression analyses, adjusted for demographics (age, sex and educational level of adolescents), were conducted to examine personal, social, and game-related correlates of active gaming ≥1 hour per week (h/wk) and non-active gaming >7 h/wk.
Results
Active gaming ≥1 h/wk was significantly associated with a more positive attitude toward active gaming (OR 5.3, CI 2.4-11.8; P<.001), a less positive attitude toward non-active games (OR 0.30, CI 0.1-0.6; P=.002), a higher score on habit strength regarding gaming (OR 1.9, CI 1.2-3.2; P=.008) and having brothers/sisters (OR 6.7, CI 2.6-17.1; P<.001) and friends (OR 3.4, CI 1.4-8.4; P=.009) who spend more time on active gaming and a little bit lower score on game engagement (OR 0.95, CI 0.91-0.997; P=.04). Non-active gaming >7 h/wk was significantly associated with a more positive attitude toward non-active gaming (OR 2.6, CI 1.1-6.3; P=.035), a stronger habit regarding gaming (OR 3.0, CI 1.7-5.3; P<.001), having friends who spend more time on non-active gaming (OR 3.3, CI 1.46-7.53; P=.004), and a more positive image of a non-active gamer (OR 2, CI 1.07–3.75; P=.03).
Conclusions
Various factors were significantly associated with active gaming ≥1 h/wk and non-active gaming >7 h/wk. Active gaming is most strongly (negatively) associated with attitude with respect to non-active games, followed by observed active game behavior of brothers and sisters and attitude with respect to active gaming (positive associations). On the other hand, non-active gaming is most strongly associated with observed non-active game behavior of friends, habit strength regarding gaming and attitude toward non-active gaming (positive associations). Habit strength was a correlate of both active and non-active gaming, indicating that both types of gaming are habitual behaviors. Although these results should be interpreted with caution because of the limitations of the study, they do provide preliminary insights into potential correlates of active and non-active gaming that can be used for further research as well as preliminary direction for the development of effective intervention strategies for replacing non-active gaming by active gaming among adolescents.
doi:10.2196/games.3092
PMCID: PMC4307820  PMID: 25654657
video games; interactive games; active games; adolescent; sedentary lifestyle; physical activity; determinants
11.  Active and sedentary behaviours in children aged 7 to 10 years old: the urban and rural contexts, Brazil 
BMC Public Health  2014;14(1):1174.
Background
Although the effects of physical activity (PA) on health and wellness are well-established, incorporating sedentary behaviours in the daily lives of populations from high- and medium-income countries is becoming increasingly common. Regardless of other factors, the area of residence can influence the physical activity level and sedentary behaviours. The aim of this study was to identify and analyse active and sedentary behaviours and factors associated with physical activity in two different geographical areas in south-eastern Brazil.
Methods
1.770 schoolchildren aged 7-10 years old were studied. Parents or caregivers completed a validated questionnaire on PA and sedentary behaviours. Screen time (ST) was calculated from the time spent watching television, playing video games and using the computer. The level of active PA (>300 minutes per week) was identified and compared between the areas of study. Parametric and non-parametric tests and Poisson regression model with robust variance were used for statistical analysis.
Results
Compared to schoolchildren from the urban area, those from the rural area showed a higher percentage of compliance with the PA recommendations (87 vs. 69.7%) and screen time <2 h (34.8 vs. 18.8%) and less participation in supervised PA. Active commuting to school was more common among schoolchildren from urban areas, although using a bicycle was more common in rural areas. The characteristics of children who do not meet the recommended weekly PA are as follows: being female, living in urban areas, being overweight, not using video games or performing supervised PA. Total ST as well as daily use of television and the computer was not associated with physical activity level in the present sample. Participation in supervised physical activities in both areas was found to increase the prevalence of being active in the areas studied.
Conclusions
The results of the present study suggest that while schoolchildren from rural areas are more active and spend less time on sedentary activities than those from the urban area, the time spent in sedentary behaviors, such as watching television, playing video games and using the computer, is high in both contexts, and it is not associated with physical activity recommendation compliance.
doi:10.1186/1471-2458-14-1174
PMCID: PMC4251846  PMID: 25404524
Child; Sedentary lifestyle; Physical activity; Urban health; Rural health
12.  TV Viewing and Physical Activity Are Independently Associated with Metabolic Risk in Children: The European Youth Heart Study 
PLoS Medicine  2006;3(12):e488.
Background
TV viewing has been linked to metabolic-risk factors in youth. However, it is unclear whether this association is independent of physical activity (PA) and obesity.
Methods and Findings
We did a population-based, cross-sectional study in 9- to 10-y-old and 15- to 16-y-old boys and girls from three regions in Europe (n = 1,921). We examined the independent associations between TV viewing, PA measured by accelerometry, and metabolic-risk factors (body fatness, blood pressure, fasting triglycerides, inverted high-density lipoprotein (HDL) cholesterol, glucose, and insulin levels). Clustered metabolic risk was expressed as a continuously distributed score calculated as the average of the standardized values of the six subcomponents. There was a positive association between TV viewing and adiposity (p = 0.021). However, after adjustment for PA, gender, age group, study location, sexual maturity, smoking status, birth weight, and parental socio-economic status, the association of TV viewing with clustered metabolic risk was no longer significant (p = 0.053). PA was independently and inversely associated with systolic and diastolic blood pressure, fasting glucose, insulin (all p < 0.01), and triglycerides (p = 0.02). PA was also significantly and inversely associated with the clustered risk score (p < 0.0001), independently of obesity and other confounding factors.
Conclusions
TV viewing and PA may be separate entities and differently associated with adiposity and metabolic risk. The association between TV viewing and clustered metabolic risk is mediated by adiposity, whereas PA is associated with individual and clustered metabolic-risk indicators independently of obesity. Thus, preventive action against metabolic risk in children may need to target TV viewing and PA separately.
A study of over 1,900 European children showed that TV viewing and physical activity in children are separately associated with obesity and metabolic risk.
Editors' Summary
Background.
Childhood obesity is a rapidly growing problem. Twenty-five years ago, overweight children were rare. Now, 155 million of the world's children are overweight, and 30–45 million are obese. Both conditions are diagnosed by comparing a child's body mass index (BMI; weight divided by height squared) with the average BMI for their age and sex. Being overweight during childhood is worrying because it is one of the so-called metabolic-risk factors that increase the chances of developing diabetes, heart problems, or strokes later in life. Other metabolic-risk factors are fatness around the belly, blood-fat disorders, high blood pressure, and problems with how the body uses insulin and blood sugar. Until recently, like obesity, these other metabolic-risk factors were seen only in adults, but now they are becoming increasingly common in children. In the US, 1 in 20 adolescents has metabolic syndrome—three or more of these risk factors. Environmental and behavioural changes have probably contributed to the increase in metabolic syndrome in children. As a group, they tend to be less physically active nowadays and they eat bigger portions of energy-dense foods more often. Increased TV viewing during childhood (and the use of other media such as computer games) has also been linked to increased obesity and to poorer health as an adult.
Why Was This Study Done?
One popular theory is that TV viewing may affect obesity and other metabolic-risk factors by displacing PA. Instead of playing in the yard after school, the theory suggests, children laze about in front of the TV. However, there is limited evidence to support this idea, and health professionals need to know whether TV viewing and PA are related, and how they affect metabolic-risk factors, in order to improve children's health. In this study, the researchers examined the associations between TV viewing, PA, and metabolic-risk factors in European children.
What Did the Researchers Do and Find?
The researchers enrolled nearly 2,000 children in two age groups from three areas in Europe. They measured the children's height and weight, estimated how fat they were by measuring skin fold thickness, measured their blood pressure, and examined the levels of glucose, insulin, and different fats in their blood. The children completed a computer questionnaire about the lengths of time for which they watched TV and how often they ate while doing so, and their PA was measured using a device called an accelerometer that each child wore for four days. When these data were analyzed statistically, the researchers found that TV viewing was slightly associated with clustered metabolic risk (the average of the individual metabolic-risk factors). This association was due to an association between TV viewing and obesity—the children who watched most TV tended to be the fattest children. However, TV viewing was not related to PA. The most active children were not necessarily those who watched least TV. Most importantly, PA was related to all individual risk factors except for obesity and with clustered metabolic risk. These associations were independent of obesity.
What Do These Findings Mean?
These results suggest that TV viewing does not damage children's health by displacing PA as popularly believed. The finding that the association between TV viewing and clustered metabolic-risk factors is mediated by obesity suggests that targeting behaviours like eating while watching TV might be a good way to improve children's health. Indeed, the researchers provide some evidence that eating while watching TV is associated with being overweight, but the results of this post hoc analysis—one that was not planned in advance—need to be confirmed. Another limitation of the study is the possibility that the children inaccurately reported their TV watching habits. Also, because measurements of metabolic-risk factors were made only once, it is impossible to say whether TV viewing or lack of PA actually causes an increase in metabolic-risk factors.
Nevertheless, these results strongly suggest that promoting PA is beneficial in relation to metabolic-risk factors, but less so in relation to obesity in childhood. TV viewing and PA should be treated as separate targets in programs designed to reverse the obesity and metabolic-syndrome epidemic in children.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/doi:10.1371/journal.pmed.0030488.
US Centers for Disease Control and Prevention, information on overweight and obesity
International Obesity Taskforce, information on obesity and its prevention, particularly in childhood
Global Prevention Alliance, details of international efforts to halt the obesity epidemic and its associated chronic diseases
American Heart Association, information for patients and professionals on metabolic syndrome and children's health
doi:10.1371/journal.pmed.0030488
PMCID: PMC1705825  PMID: 17194189
13.  Adult Consequences of Late Adolescent Alcohol Consumption: A Systematic Review of Cohort Studies 
PLoS Medicine  2011;8(2):e1000413.
In a systematic review of cohort studies of adolescent drinking and later outcomes, Jim McCambridge and colleagues show that although studies suggest links to worse adult physical and mental health and social consequences, existing evidence is of poor quality.
Background
Although important to public policy, there have been no rigorous evidence syntheses of the long-term consequences of late adolescent drinking.
Methods and Findings
This systematic review summarises evidence from general population cohort studies of drinking between 15–19 years old and any subsequent outcomes aged 20 or greater, with at least 3 years of follow-up study. Fifty-four studies were included, of which 35 were assessed to be vulnerable to bias and/or confounding. The principal findings are: (1) There is consistent evidence that higher alcohol consumption in late adolescence continues into adulthood and is also associated with alcohol problems including dependence; (2) Although a number of studies suggest links to adult physical and mental health and social consequences, existing evidence is of insufficient quality to warrant causal inferences at this stage.
Conclusions
There is an urgent need for high quality long-term prospective cohort studies in order to better understand the public health burden that is consequent on late adolescent drinking, both in relation to adult drinking and more broadly. Reducing drinking during late adolescence is likely to be important for preventing long-term adverse consequences as well as protecting against more immediate harms.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
The effects of alcohol intoxication (drunkenness), dependence (habitual, compulsive, and long-term drinking), and the associated biochemical changes, have wide-ranging health and social consequences, some of which can be lethal. Worldwide, alcohol causes 2.5 million deaths (3.8% of total) and 69.4 million (4.5% of total) of disability-adjusted life years (DALYs). Unintentional injuries alone account for about one-third of the 2.5 million deaths, whereas neuro-psychiatric conditions account for almost 40%. There is also a causal relationship between alcohol consumption and more than 60 types of disease and injury; worldwide, alcohol is estimated to cause about 20%–30% cases of esophageal cancer, liver cancer, cirrhosis of the liver, homicide, epilepsy, and motor vehicle crashes. There is increasing evidence that, in addition to the volume of alcohol consumed, the pattern of drinking has an effect on health outcomes, with binge drinking found to be particularly harmful. As the majority of people who binge drink are teenagers, this group may be particularly vulnerable to the damaging health effects of alcohol, leading to global concern about the drinking trends and patterns among young people.
Why Was This Study Done?
Although there have been many published cohort studies reporting the longer term harms associated with adolescent drinking, the strength of this evidence remains unclear, which has implications for the objectives of interventions. For example, if adolescent drinking does not cause later difficulties, early intervention on, and management of, the acute consequences of alcohol consumption, such as antisocial behaviour and unintentional injuries, may be the most appropriate community safety and public health responses. However, if there is a causal relationship, there needs to be an additional approach that addresses the cumulative harmful effects of alcohol. The researchers conducted this systematic review of cohort studies, as this method provides the strongest observational study design to evaluate evidence of causality.
What Did the Researchers Do and Find?
The researchers conducted a comprehensive literature review to identify relevant studies that met their inclusion criteria, which were: (1) data collection from at least two points in time, at least 3 years apart, from the same cohort; (2) data collection regarding alcohol consumption between the ages of 15 and 19 years old; and (3) inclusion of a report of at least one quantitative measure of effect, such as an odds ratio, between alcohol involvement and any later outcome assessed at age 20 or greater. The majority of these studies were multiple reports from ten cohorts and approximately half were from the US. The researchers then evaluated the strength of causal inference possible in these studies by assessing whether all possible contributing factors(confounders) had been taken into account, identifying studies that had follow-up rates of 80% or greater, and which had sample sizes of 1,000 participants or more.
Using these methods, the researchers found that, overall, there is consistent evidence that higher alcohol consumption in late adolescence continues into adulthood and is also associated with alcohol problems, including dependence. For example, one population-based cohort showed that late adolescent drinking can cause early death among men, mainly through car crashes and suicides, and there was a large evidence base supporting the ongoing impacts of late adolescent drinking on adult drinking behaviours—although most of these studies could not strongly support causal inferences because of their weak designs. The researchers also concluded that although a number of studies suggested links with late adolescent drinking to adult physical and mental health and social consequences, this evidence is generally of poor quality and insufficient to infer causality.
What Do These Findings Mean?
The results of this study show that that the evidence-base on the long-term consequences of late adolescent drinking is not as extensive or compelling as it needs to be. The researchers stress that there is an urgent need for high quality long-term prospective cohort studies in order to better understand the public health burden associated with adolescent drinking in general and in relation to adult drinking. However, there is sufficient evidence to suggest that reducing drinking during late adolescence is likely to be important for preventing long-term adverse consequences as well as protecting against more immediate harmful consequences harms.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000413.
The World Health Organization has information about the global incidence of alcohol consumption
The US-based Marin Institute has information about alcohol and young people
The BBC also has a site on late adolescent drinking
doi:10.1371/journal.pmed.1000413
PMCID: PMC3035611  PMID: 21346802
14.  Combined Impact of Health Behaviours and Mortality in Men and Women: The EPIC-Norfolk Prospective Population Study 
PLoS Medicine  2008;5(1):e12.
Background
There is overwhelming evidence that behavioural factors influence health, but their combined impact on the general population is less well documented. We aimed to quantify the potential combined impact of four health behaviours on mortality in men and women living in the general community.
Methods and Findings
We examined the prospective relationship between lifestyle and mortality in a prospective population study of 20,244 men and women aged 45–79 y with no known cardiovascular disease or cancer at baseline survey in 1993–1997, living in the general community in the United Kingdom, and followed up to 2006. Participants scored one point for each health behaviour: current non-smoking, not physically inactive, moderate alcohol intake (1–14 units a week) and plasma vitamin C >50 mmol/l indicating fruit and vegetable intake of at least five servings a day, for a total score ranging from zero to four. After an average 11 y follow-up, the age-, sex-, body mass–, and social class–adjusted relative risks (95% confidence intervals) for all-cause mortality(1,987 deaths) for men and women who had three, two, one, and zero compared to four health behaviours were respectively, 1.39 (1.21–1.60), 1.95 (1.70–-2.25), 2.52 (2.13–3.00), and 4.04 (2.95–5.54) p < 0.001 trend. The relationships were consistent in subgroups stratified by sex, age, body mass index, and social class, and after excluding deaths within 2 y. The trends were strongest for cardiovascular causes. The mortality risk for those with four compared to zero health behaviours was equivalent to being 14 y younger in chronological age.
Conclusions
Four health behaviours combined predict a 4-fold difference in total mortality in men and women, with an estimated impact equivalent to 14 y in chronological age.
From a large prospective population study, Kay-Tee Khaw and colleagues estimate the combined impact of four behaviors--not smoking, not being physically inactive, moderate alcohol intake, and at least five vegetable servings a day--amounts to 14 additional years of life.
Editors' Summary
Background.
Every day, or so it seems, new research shows that some aspect of lifestyle—physical activity, diet, alcohol consumption, and so on—affects health and longevity. For the person in the street, all this information is confusing. What is a healthy diet, for example? Although there are some common themes such as the benefit of eating plenty of fruit and vegetables, the details often differ between studies. And exactly how much physical activity is needed to improve health? Is a gentle daily walk sufficient or simply a stepping stone to doing enough exercise to make a real difference? The situation with alcohol consumption is equally confusing. Small amounts of alcohol apparently improve health but large amounts are harmful. As a result, it can be hard for public-health officials to find effective ways to encourage the behavioral changes that the scientific evidence suggests might influence the health of populations.
Why Was This Study Done?
There is another factor that is hindering official attempts to provide healthy lifestyle advice to the public. Although there is overwhelming evidence that individual behavioral factors influence health, there is very little information about their combined impact. If the combination of several small differences in lifestyle could be shown to have a marked effect on the health of populations, it might be easier to persuade people to make behavioral changes to improve their health, particularly if those changes were simple and relatively easy to achieve. In this study, which forms part of the European Prospective Investigation into Cancer and Nutrition (EPIC), the researchers have examined the relationship between lifestyle and the risk of dying using a health behavior score based on four simply defined behaviors—smoking, physical activity, alcohol drinking, and fruit and vegetable intake.
What Did the Researchers Do and Find?
Between 1993 and 1997, about 20,000 men and women aged 45–79 living in Norfolk UK, none of whom had cancer or cardiovascular disease (heart or circulation problems), completed a health and lifestyle questionnaire, had a health examination, and had their blood vitamin C level measured as part of the EPIC-Norfolk study. A health behavior score of between 0 and 4 was calculated for each participant by giving one point for each of the following healthy behaviors: current non-smoking, not physically inactive (physical inactivity was defined as having a sedentary job and doing no recreational exercise), moderate alcohol intake (1–14 units a week; a unit of alcohol is half a pint of beer, a glass of wine, or a shot of spirit), and a blood vitamin C level consistent with a fruit and vegetable intake of at least five servings a day. Deaths among the participants were then recorded until 2006. After allowing for other factors that might have affected their likelihood of dying (for example, age), people with a health behavior score of 0 were four times as likely to have died (in particular, from cardiovascular disease) than those with a score of 4. People with a score of 2 were twice as likely to have died.
What Do These Findings Mean?
These findings indicate that the combination of four simply defined health behaviors predicts a 4-fold difference in the risk of dying over an average period of 11 years for middle-aged and older people. They also show that the risk of death (particularly from cardiovascular disease) decreases as the number of positive health behaviors increase. Finally, they can be used to calculate that a person with a health score of 0 has the same risk of dying as a person with a health score of 4 who is 14 years older. These findings need to be confirmed in other populations and extended to an analysis of how these combined health behaviors affect the quality of life as well as the risk of death. Nevertheless, they strongly suggest that modest and achievable lifestyle changes could have a marked effect on the health of populations. Armed with this information, public-health officials should now be in a better position to encourage behavior changes likely to improve the health of middle-aged and older people.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050012.
The MedlinePlus encyclopedia contains a page on healthy living (in English and Spanish)
The MedlinePlus page on seniors' health contains links to many sites dealing with healthy lifestyles and longevity (in English and Spanish)
The European Prospective Investigation into Cancer and Nutrition (EPIC) study is investigating the relationship between nutrition and lifestyle and the development of cancer and other chronic diseases; information about the EPIC-Norfolk study is also available
The US Centers for Disease Control and Prevention provides information on healthy aging for older adults, including information on health-related behaviors (in English and Spanish)
The UK charity Age Concerns provides a fact sheet about staying healthy in later life
The London Health Observatory, which provides information for policy makers and practitioners about improving health and health care, has a section on how lifestyle and behavior affect health
doi:10.1371/journal.pmed.0050012
PMCID: PMC2174962  PMID: 18184033
15.  Volume, patterns, and types of sedentary behavior and cardio-metabolic health in children and adolescents: a cross-sectional study 
BMC Public Health  2011;11:274.
Background
Cardio-metabolic risk factors are becoming more prevalent in children and adolescents. A lack of moderate-to-vigorous intensity physical activity (MVPA) is an established determinant of cardio-metabolic risk factors in children and adolescents. Less is known about the relationship between sedentary behavior and cardio-metabolic health. Therefore, the objective was to examine the independent associations between volume, patterns, and types of sedentary behavior with cardio-metabolic risk factors among children and adolescents.
Methods
The results are based on 2527 children and adolescents (6-19 years old) from the 2003/04 and 2005/06 National Health and Nutrition Examination Surveys (NHANES). A cardio-metabolic risk score (CRS) was calculated based on age- and sex-adjusted waist circumference, systolic blood pressure, non-high-density lipoprotein cholesterol, and C-reactive protein values. Volume and patterns of sedentary behavior and moderate-to-vigorous physical activity (MVPA) were measured objectively using accelerometers. Types of sedentary behavior were measured by questionnaire. A series of logistic regression models were used to examine associations.
Results
Volume and patterns of sedentary behavior were not predictors of high CRS after adjusting for MVPA and other confounders (P > 0.1). For types of sedentary behavior, high TV use, but not high computer use, was a predictor of high CRS after adjustment for MVPA and other confounders. Children and adolescents who watched ≥4 hours per day of TV were 2.53 (95% confidence interval: 1.45-4.42) times more likely to have high CRS than those who watched <1 hour per day. MVPA predicted high CRS after adjusting for all sedentary behavior measures and other confounders. After adjustment for waist circumference, MVPA also predicted high non-obesity CRS; however, the same relationship was not seen with TV use.
Conclusion
No association was observed between overall volume and patterns of sedentary behavior with cardio-metabolic risk factors in this large sample of children and adolescents. Conversely, high TV use and low MVPA were independently associated with cardio-metabolic risk factors. However, the association between high TV use and clustered cardio-metabolic risk factors appears to be mediated or confounded by obesity. Thus, TV and MVPA appear to be two separate behaviors that need to be targeted with different interventions and policies.
doi:10.1186/1471-2458-11-274
PMCID: PMC3112118  PMID: 21542910
16.  Determinants of Overweight and Obesity in Affluent Adolescent in Surat City, South Gujarat region, India 
Background:
Obesity is a major global burden. Low levels of physical activity, TV watching, and dietary pattern are modifiable risk factors for overweight and obesity in adolescent.
Objective:
The objective of this study was to determine risk factors for overweight and obesity among affluent adolescent, in Surat city in south Gujarat.
Design:
Cross sectional from July 2009 to April 2010.
Setting:
Two private schools with tuition fees more than Rs. 2000 per month, were selected randomly using a random table.
Participants:
The participants were adolescents, 12 to 15 years of age.
Data collection:
Pre-designed and pre-tested questionnaire was used to elicit the information about dietary history and physical activity.
Measurement:
Height and weight was measured and BMI was calculated. Overweight and obesity were assessed by BMI for age. Student who had BMI for age <85th and <95th percentile of reference population were classified as overweight and BMI for age <95th percentile of reference population were classified as obese (IAP Growth Monitoring Guidelines for Children from Birth to 18 Year).
Result:
The overall prevalence of obesity and overweight was 6.55% and 13.9% (boys: 6.7% and 15.1%; girls 6.4% and 13.35%). Final model of multiple logistic regression analysis showed that important determinants of overweight and obesity were low levels of physical activity, watching television or playing computer games, and consuming junk foods, snacks and carbonated drinks.
Conclusion:
The magnitude of obesity and overweight among affluent adolescent of Surat city was found to be 6.55% and 13.9%, respectively. Low level of physical activity, watching TV or playing computer games, and dietary pattern predisposed the adolescent to overweight/obesity.
doi:10.4103/0970-0218.91418
PMCID: PMC3263151  PMID: 22279261
Adolescent; India; obesity; risk factors
17.  Risk Factors of Adolescent Obesity in Taiwan and Its Association with Physical activity, Blood Pressure and Waist Circumference 
Asian Journal of Sports Medicine  2010;1(4):214-222.
Purpose
This study was conducted to investigate risk factors of obesity and its associated health problems in adolescence in Taiwan.
Methods
We enrolled 559 adolescent volunteers with equal numbers of females and males in 2008. Participants were divided into two groups: obese (body mass index [BMI] ≧95th percentile) and normal-weight adolescents (BMI: 15th ∼ 85th percentile). Each of them completed a questionnaire about lifestyle and parents’ stature.
Results
Obese mother had high likelihood of having obese girls and boys (P=0.001). Obese girls spent more time in watching TV (P=0.03) and had higher frequency of having sweetened soft drinks (P=0.016) than normal-weight group. Girls spent more time in TV watching associated higher frequency of having sweetened soft drinks (P=0.012). In boys, this associated with higher frequency of eating snick (P=0.018) and larger waist circumference (P=0.011). Boys who had more frequent effective exercise had lower frequency of eating outside (P=0.01) and more services of vegetables (P=0.002). There was no relation between hypertension and adolescent physical activity. Regardless of gender, obese group had higher waist circumference and blood pressure than normal-weight group (P<0.001).
Conclusion
There was a strong association between obese mother and adolescent obesity. More physical activity in adolescents associated with healthier dietary behaviors. Obese adolescents have higher waist circumference and blood pressure.
PMCID: PMC3289182  PMID: 22375210
Physical activity; Adolescent; Blood pressure; Waist circumference: Risk factor; Obesity
18.  Recreational Screen-Time Among Chinese Adolescents: A Cross-Sectional Study 
Journal of Epidemiology  2014;24(5):397-403.
Background
Rapid urbanization in China has led to a proliferation of electronic entertainment media among youth. Prolonged screen time (ST; includes watching television and playing on computers, video game consoles, or mobile phones) is linked to poor health profiles. The aim of this study was to report recreational ST behaviors and ST correlates among Chinese adolescents living in two regions with different degrees of urbanization.
Methods
A cross-sectional, school-based survey (n = 3461 adolescents; aged 12–14 years old) living in inner-city Shanghai and a peri-urban region of Hangzhou. Students completed a questionnaire including family characteristics, daily ST, and information on family environment related to screen use. Recreational ST was categorized into two groups according to recommendations by the American Academy of Pediatrics (< or ≥2 h/day). Parents reported their own ST and also reported educational attainment as a proxy for socioeconomic status.
Results
ST was higher among boys than girls and on weekends than weekdays. Peri-urban girls were more likely to exceed 2 h/day ST compared to inner-city girls on weekends. Having a father with no university degree, mother’s TV viewing ≥2 h/day, no ST rules at home, and eating meals in front of the TV were associated with higher ST on both weekdays and weekends, and regional differences were found for weekend ST.
Conclusions
TV viewing and playing on the computer were the most prevalent ST behaviors among Chinese adolescents. Mobile phone playing was less prevalent but persistent throughout the week. More population-level surveillance and research is needed to monitor the trends in ST behaviors and to better understand the characteristics of those who are at risk.
doi:10.2188/jea.JE20140006
PMCID: PMC4150011  PMID: 24930472
screen time; adolescents; China; urban
19.  Modifiable risk factors for overweight and obesity in children and adolescents from São Paulo, Brazil 
BMC Public Health  2011;11:585.
Background
Brazil is currently experiencing a nutrition transition: the displacement of traditional diets with foods high in saturated fat, sodium, and cholesterol and an increase in sedentary lifestyles. Despite these trends, our understanding of child obesity in Brazil is limited. Thus, the aims of this study were (1) to investigate the current prevalence of overweight and obesity in a large sample of children and adolescents living in São Paulo, Brazil, and (2) to identify the lifestyle behaviors associated with an increased risk of obesity in young Brazilians.
Methods
A total of 3,397 children and adolescents (1,596 male) aged 7-18 years were randomly selected from 22 schools in São Paulo, Brazil. Participants were classified as normal weight, overweight, or obese based on international age- and sex-specific body mass index thresholds. Selected sociodemographic, physical activity, and nutrition behaviors were assessed via questionnaire.
Results
Overall, 19.4% of boys and 16.1% of girls were overweight while 8.9% and 4.3% were obese. Two-way analysis of variance revealed that the prevalence of overweight and obesity was significantly higher in boys and in younger children when compared to girls and older children, respectively (P < 0.05 for both). Logistic regression analysis revealed that overweight was associated with more computer usage, parental encouragement to be active, and light soft drink consumption after controlling for differences in sex, age, and parental education (P < 0.05 for all). Conversely, overweight was associated with less active transport to school, eating before sleep, and consumption of breakfast, full-sugar soft drinks, fried food and confectionery (P < 0.05 for all).
Conclusions
Our results show that obesity in São Paulo children and adolescents has reached a level equivalent to that seen in many developed countries. We have also identified three key modifiable factors related to obesity that may be appropriate targets for future intervention in Brazilian youth: transport mode to school, computer usage, and breakfast consumption.
doi:10.1186/1471-2458-11-585
PMCID: PMC3154175  PMID: 21781313
20.  Lifestyle factors associated with overweight and obesity among Saudi adolescents 
BMC Public Health  2012;12:354.
Background
A better understanding of the relationships between obesity and lifestyle factors is necessary for effective prevention and management of obesity in youth. Therefore, the objective of this study was to evaluate the associations between obesity measures and several lifestyle factors, including physical activity, sedentary behaviors and dietary habits among Saudi adolescents aged 14–19 years.
Methods
This was a school-based cross-sectional study that was conducted in three cities in Saudi Arabia (Al-Khobar, Jeddah and Riyadh). The participants were 2906 secondary school males (1400) and females (1506) aged 14–19 years, who were randomly selected using a multistage stratified cluster sampling technique. Measurements included weight, height, body mass index (BMI), waist circumference, waist/height ratio (WHtR), screen time (television viewing, video games and computer use), physical activity (determined using a validated questionnaire), and dietary habits (intake frequency per week). Logistic regression was used to examine the associations between obesity and lifestyle factors.
Results
Compared with non-obese, obese males and females were significantly less active, especially in terms of vigorous activity, had less favorable dietary habits (e.g., lower intake of breakfast, fruits and milk), but had lower intake of sugar-sweetened drinks and sweets/chocolates. Logistic regression analysis showed that overweight/obesity (based on BMI categories) or abdominal obesity (based on WHtR categories) were significantly and inversely associated with vigorous physical activity levels (aOR for high level = 0.69, 95% CI 0.41–0.92 for BMI and 0.63, 95% CI 0.45–0.89 for WHtR) and frequency of breakfast (aOR for < 3 days/week = 1.44; 95% CI 1.20–1.71 for BMI and 1.47; 95% CI 1.22–1.76 for WHtR) and vegetable (aOR for < 3 days/week = 1.29; 95% CI 1.03–1.59 for WHtR) intakes, and consumption of sugar-sweetened beverages (aOR for < 3 days/week = 1.32; 95% CI 1.08–1.62 for BMI and 1.42; 95% CI 1.16–1.75 for WHtR).
Conclusions
The present study identified several lifestyle factors associated with obesity that may represent valid targets for the prevention and management of obesity among Saudi adolescents. Primary prevention of obesity by promoting active lifestyles and healthy diets should be a national public health priority.
doi:10.1186/1471-2458-12-354
PMCID: PMC3433359  PMID: 22591544
Adolescents; Dietary habits; Lifestyle; Overweight; Obesity; Physical activity; Saudi Arabia; Sedentary behaviors
21.  Health Behavior among Lithuania’s Adolescents in Context of European Union 
Croatian medical journal  2006;47(2):335-343.
Aim
To compare health behavior patterns of adolescents in Lithuania with health behavior of adolescents in European Union (EU) in 2001/2002.
Methods
The study was carried out in conformity with the methodology of Health Behavior in School-aged Children: a World Health Organization cross-national study. Three country representative samples of schoolchildren, aged 11, 13, and 15, were surveyed in 25 EU countries and regions in 2001/2002 school year. The study instrument was a standardized questionnaire that included questions on alcohol consumption, smoking, illegal drugs use, physical activity, and other patterns of health behavior. The rate or mean values of the targeted health behavior of Lithuanian students were assessed and compared to those calculated as an average for the EU countries and regions.
Results
We found an early onset of alcohol consumption among Lithuanian boys. Lithuanian boys and girls across all age groups reported being drunk two and more times more often than their peers from other EU member states. Lithuanian 15-year-old boys smoked more often that did their European peers, while girls smoke more rarely. The prevalence of drugs (marihuana group) use among Lithuanian students is relatively low: the prevalence of drug use among 15-year-olds in Lithuania is two times lower than the prevalence in other EU countries and regions (11.2% vs 24.5% for boys and 4.5% vs 18.3% for girls, respectively). Physical activity of Lithuanian adolescents is rather high in comparison with their EU peers, although many students watch television for ≥4 hours a day. Lithuanian students did not eat sweets often, or drank soft drinks (Coca Cola and other), and they ate fruits and had breakfast every school day. With respect to hygienic habits, approximately only one in 3 boys and every second girl brushed their teeth more than once a day.
Conclusions
There are health behavior differences between adolescents in Lithuania and those in other EU countries. The disparities among health behavior of young people in EU countries and regions require Lithuanian and EU health policy to develop initiatives aimed at decreasing health behavior inequalities.
PMCID: PMC2080392  PMID: 16625702
22.  Patterns and Correlates of Physical Activity and Nutrition Behaviors in Adolescents 
Background
Knowledge of the prevalence, clustering, and correlates of multiple adolescent health behaviors can inform the design of health promotion interventions.
Methods
A cross-sectional design was used to assess 878 adolescents aged 11 to 15 years (53.6% girls; 58% non-Hispanic white) recruited in primary care clinics in 2001–2002. Adolescent physical activity (assessed with accelerometers); television viewing time (reported); percent calories from fat; and servings of fruits and vegetables (assessed with multiple 24-hour recalls) were dichotomized into meeting or not meeting national guidelines. Parent health behaviors were assessed with self-reported measures. Analyses were conducted in 2006.
Results
Fifty-five percent of adolescents did not meet the physical activity guideline, and 30% exceeded 2 hours daily of television viewing time, with boys more active and less sedentary than girls (p <0.01). The majority of the adolescents did not meet dietary guidelines. Nearly 80% had multiple risk behaviors and only 2% met all four guidelines. The number of risk behaviors was associated with being older and being at risk for overweight or being overweight, for boys and girls (p <0.05). Having a parent with a history of smoking and who did not meet the fruit and vegetable guideline were significantly associated with a higher number of risk behaviors for girls (p <0.05).
Conclusion
Eight of ten adolescents in this sample failed to meet guidelines for two or more diet, physical activity, and sedentary risk behaviors. Some parent health behaviors, along with the adolescent’s weight status and age, were associated with a higher number of adolescent health risk behaviors.
doi:10.1016/j.amepre.2006.10.012
PMCID: PMC1913476  PMID: 17197153
23.  Associations Between Screen-Based Sedentary Behavior and Cardiovascular Disease Risk Factors in Korean Youth 
Journal of Korean Medical Science  2012;27(4):388-394.
The purposes of this study were to: 1) describe the patterns of screen-based sedentary behaviors, and 2) examine the association between screen-based sedentary behavior and cardiovascular disease (CVD) risk factors in representative Korean children and adolescents, aged 12 to 18 yr, in the Korean National Health and Nutrition Examination Survey. Screen-based sedentary behavior was measured using self-report questionnaires that included items for time spent watching TV and playing PC/video games. Physical activity was measured using items for frequency and duration of moderate-to-vigorous physical activity (MVPA). CVD risk factors such as body mass index (BMI), waist circumference, LDL cholesterol, HDL cholesterol, total cholesterol, triglycerides, glucose, systolic blood pressure, and diastolic blood pressure were measured. Boys spent more time playing PC/video games, and girls spent more time watching TV. After adjusting for age, gender, annual household income, and MVPA, an additional hour of watching TV was significantly associated with the risk of overweight (OR 1.17 [95% CI 1.03-1.33]), high abdominal adiposity (OR 1.27 [1.06-1.51]), and low HDL cholesterol (OR 1.27 [1.10-1.47]). An additional hour spent playing PC/video games also increased the risk of high abdominal adiposity (OR 1.20 [1.03-1.40]). Prospective observations and interventions are needed to determine causal relationships between screen-based sedentary behavior and CVD risk profiles in Korean youth.
doi:10.3346/jkms.2012.27.4.388
PMCID: PMC3314851  PMID: 22468102
Adolescent; CVD Risk Factors; KNHANES; Physical Activity; Sedentary Behavior
24.  Neighborhood disorder and screen time among 10-16 year old Canadian youth: A cross-sectional study 
Background
Screen time activities (e.g., television, computers, video games) have been linked to several negative health outcomes among young people. In order to develop evidence-based interventions to reduce screen time, the factors that influence the behavior need to be better understood. High neighborhood disorder, which may encourage young people to stay indoors where screen time activities are readily available, is one potential factor to consider.
Methods
Results are based on 15,917 youth in grades 6-10 (aged 10-16 years old) who participated in the Canadian 2009/10 Health Behaviour in School-aged Children Survey (HBSC). Total hours per week of television, video games, and computer use were reported by the participating students in the HBSC student questionnaire. Ten items of neighborhood disorder including safety, neighbors taking advantage, drugs/drinking in public, ethnic tensions, gangs, crime, conditions of buildings/grounds, abandoned buildings, litter, and graffiti were measured using the HBSC student questionnaire, the HBSC administrator questionnaire, and Geographic Information Systems. Based upon these 10 items, social and physical neighborhood disorder variables were derived using principal component analysis. Multivariate multilevel logistic regression analyses were used to examine the relationship between social and physical neighborhood disorder and individual screen time variables.
Results
High (top quartile) social neighborhood disorder was associated with approximately 35-45% increased risk of high (top quartile) television, computer, and video game use. Physical neighborhood disorder was not associated with screen time activities after adjusting for social neighborhood disorder. However, high social and physical neighborhood disorder combined was associated with approximately 40-60% increased likelihood of high television, computer, and video game use.
Conclusion
High neighborhood disorder is one environmental factor that may be important to consider for future public health interventions and strategies aiming to reduce screen time among youth.
doi:10.1186/1479-5868-9-66
PMCID: PMC3420264  PMID: 22651908
Screen time; Neighborhood disorder; Youth
25.  Active video games as a tool to prevent excessive weight gain in adolescents: rationale, design and methods of a randomized controlled trial 
BMC Public Health  2014;14:275.
Background
Excessive body weight, low physical activity and excessive sedentary time in youth are major public health concerns. A new generation of video games, the ones that require physical activity to play the games –i.e. active games- may be a promising alternative to traditional non-active games to promote physical activity and reduce sedentary behaviors in youth. The aim of this manuscript is to describe the design of a study evaluating the effects of a family oriented active game intervention, incorporating several motivational elements, on anthropometrics and health behaviors in adolescents.
Methods/Design
The study is a randomized controlled trial (RCT), with non-active gaming adolescents aged 12 – 16 years old randomly allocated to a ten month intervention (receiving active games, as well as an encouragement to play) or a waiting-list control group (receiving active games after the intervention period). Primary outcomes are adolescents’ measured BMI-SDS (SDS = adjusted for mean standard deviation score), waist circumference-SDS, hip circumference and sum of skinfolds. Secondary outcomes are adolescents’ self-reported time spent playing active and non-active games, other sedentary activities and consumption of sugar-sweetened beverages. In addition, a process evaluation is conducted, assessing the sustainability of the active games, enjoyment, perceived competence, perceived barriers for active game play, game context, injuries from active game play, activity replacement and intention to continue playing the active games.
Discussion
This is the first adequately powered RCT including normal weight adolescents, evaluating a reasonably long period of provision of and exposure to active games. Next, strong elements are the incorporating motivational elements for active game play and a comprehensive process evaluation. This trial will provide evidence regarding the potential contribution of active games in prevention of excessive weight gain in adolescents.
Trial registration
Dutch Trial register NTR3228.
doi:10.1186/1471-2458-14-275
PMCID: PMC3987926  PMID: 24661535
Video games; Active games; Exergames; Physical activity; Sedentary lifestyle; Adolescent; Prevention; Excessive body weight; Overweight; Randomized controlled trial

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