A large sample of the Chinese population was studied to explore current lifestyle health behaviors among children and adolescents. Overweight and obesity were found to be highly prevalent, particularly among the male participants. Differences in health-related factors and the recognition of weight status among participants in different weight categories were observed. Obese children were more likely to be nonsnackers, to have a shorter sleep duration, and to have a higher family income.
The high prevalence of overweight/obesity in this study was in line with many other studies [5
]. It was reported that the prevalence of adolescent obesity increased dramatically from 5 to 13% in boys and from 5 to 9% in girls between 1966-70 and 1988-91 in the U.S. [21
]. Data from China also indicated that the prevalence of overweight and obesity among 7–9-year-olds increased from approximately 1–2% in 1985 to 17% among girls and 25% among boys in 2000 in big cities [22
]. The time trend of this rapidly growing epidemic was observed in both developed and developing countries [2
]. Given its huge impact on future generations, great attention should be paid to establishing appropriate prevention and treatment programs.
In the present study, we found that obese participants were more likely to be nonsnackers compared to the normal-weight ones. Several studies have investigated the association between snacking and pediatric obesity, the results of which were conflicting. Some studies suggested that snacking might increase energy intake and thus promote weight gain [24
], whereas others reported an inverse relationship between snacking and body weight [26
]. The negative association found in our study may be explained by the composition of snacks and the compensation of the energy from snacks. Summerbell et al found that snack foods, compared with meals, are actually lower in fat and higher in carbohydrates [29
]. It was also evidenced that among night snackers, eating cereal after the evening meal could reduce caloric intake and promote weight loss [30
], indicating the important role of reasonable snack composition. In a study of snack consumption for 8 weeks, no weight gain was observed regardless of the moment of consumption and energy density of snacks [31
]. This could be explained by the association between snacking and increased vigorous physical activity [26
] or by rapid physical development in this period. The increased energy intake from snacking may have been compensated by activity or growth, thus limiting the development of obesity.
A substantial amount of evidence exists regarding the link between short sleep duration and childhood and adolescent overweight or obesity [28
]. A meta-analysis including 36 publications found that short sleep duration was independently associated with weight gain, particularly in younger age groups [34
]. The present study indicated that childhood and adolescent obesity was associated with a shorter sleep duration (<7.5 h), confirming the earlier findings. The mechanisms underlying are not fully understood. Upregulation of appetite, alterations in glucose metabolism, and decreased energy expenditure might be the potential reasons for these findings [35
In our study, we found that approximately half of the parents with an overweight or obese child failed to recognize their child’s excess weight status. Approximately 35% of the parents with an obese child and 65% with an overweight child would not take measures to decrease their child’s body weight. The low rate of parental recognition of childhood overweight and obesity in this study is consistent with other studies [37
]. This phenomenon might be due to exaggerated parental concern regarding their children. They continued to feed their babies because of worries about insufficient nutrition and energy for their children. In some cultures, big children are viewed more positively as “cute and healthy” [40
], which also contributed to this situation. In addition, low recognition of excess weight status among children and adolescents was observed. These findings should be considered when planning prevention and treatment programs of pediatric obesity.
Regarding family income, Wang et al found that among children aged 6–18 years old, those in higher income groups were more likely to be obese in China and Russia, whereas those in lower income groups were at a higher risk of being obese in the U.S. [41
]. Our study indicated that obese participants were more likely to have a higher family income, similar to the result found in a Jordanian population [42
] and contrary to the result in Canadian children [43
]. The mechanism of this region-related difference requires more exploration.
Although many studies have reported that some health-related factors, such as skipping breakfast, physical inactivity, and long hours of TV watching and video game playing, were associated with childhood and adolescent obesity [28
], we failed to find statistically significant results, possibly due to the different definitions of the variables and an insufficient sample size.
There are limitations in the present study. First, our data were obtained from a cross-sectional study in rural Northeast China and are not representative of children and adolescents throughout the whole country. Extrapolating the conclusions to the general population should be done cautiously. Second, these analyses rely on self-reports from children and their parents, which might compromise the accuracy. Third, a relatively high drop of our population was observed. Although there were no significant differences in age and gender between the retained and excluded populations, this might still compromise the representativeness and the precision of the results. In addition, our results are based on a cross-sectional design, and thus, we could not define a causal association between health-related factors and weight status.