Data were obtained from the Health Behaviour in School-aged Children (HBSC) study 2001/2002, a cross-sectional survey that was carried out in 35 countries and regions across Europe, Canada, and USA, with the collaboration of the World Health Organization. The 2001/2002 survey included rich countries (such as Canada, Norway, Sweden and the United States), poor countries (such as Lithuania, the Russian Federation and Ukraine) and middle-income countries (such as Austria, Belgium- both the Flemish- and French-speaking populations, Croatia, the Czech Republic, Denmark, England, Estonia, Finland, France, Germany, Greece, Greenland, Hungary, Ireland, Israel, Italy, Latvia, Malta, the Netherlands, Poland, Portugal, Scotland, Slovenia, Spain, Switzerland, Macedonia, and Wales). Children were selected using a clustered sampling design, where the sampling unit was either the school class or the school. More than 160,000 young people took part and approximately 1500 respondents in each of the three age groups were targeted in every country.
This cross-sectional survey of 11-, 13- and 15-year-old schoolchildren is undertaken every four years. The goal of the HBSC study is to identify youth health indicators and the factors that influence them. School-based questionnaires were administered in classroom settings using standardised instructions. All the countries carried out the data collection in accordance with the international study protocol, providing a strong basis for international comparisons [24
]. More details about data collection methods can be found on the HBSC website at http://www.hbsc.org
. Countries/regions with more than 20% of missing values for BMI were excluded, resulting in a final sample of children from 24 countries/regions.
Body Weight Dissatisfaction (desire to lose weight)
Categories were derived from the following question: At present are you on a diet or doing something else to lose weight? Respondents selecting 'no, my weight is fine' were classified as satisfied with weight; respondents selecting either 'no, but I need to lose weight' or 'yes,' were classified as dissatisfied with weight. Those who reported needing to put on weight (9.4%) were excluded from this analysis, because the main focus of this analysis was to examine the relationship of communication with parents and weight dissatisfaction (dieting or perceived a need to diet) from an overweight/obesity perspective. The percentage of missing data for this measure was 0.7% randomly distributed over countries and ranged from 0.1–1.7%.
Communication with Parents (talking to mother/father)
Communication with mother and father was assessed separately with two items, worded "How easy is it for you to talk to your mother/father about things that really bother you?" Response options were: "very easy," "easy," "difficult," "very difficult," and "don't have or see this person." Responses of "very easy" and "easy" were categorized as easy to talk; responses of "difficult," "very difficult," or "don't have or see this person" were categorized as difficult to talk.
We assumed that if adolescents do not have or see their father/mother then they are not supported. In addition the percentages of dissatisfied with their body image, were quite similar for those who responded not to have/see a father/mother and those who responded to have difficulty in talking to father/mother (respectively for father: 42.4% and 45.3% and for mother: 40.3% and 45.5%), while much lower percentages were found in those who responded that it was easy to talk to their parents (32.1% for talking to father and 35.5% for talking to mother). The percentages of missing data for both talking with father and talking with mother were 2.8%, ranging from 0.1–5.5% over the countries.
Body Mass Index (BMI)
BMI was calculated using self-reported weight and height (kg/m2
). Adolescents' weight status was categorized by means of age- and gender-specific BMI international cut-off points recommended for use in international comparisons [25
]. In the present study, the group of overweight adolescents includes obese. Adolescents who did not report their weight or/and height were excluded from the analysis because BMI could not be calculated. Missing values of BMI for the included countries/region ranged from 2.9% – 18.4%.
Data analysis was performed using the SPSS Version 12. Binary logistic regression analyses were used to investigate the associations between communication with father/mother and body weight dissatisfaction, controlling for communication with the other parent, age, and BMI. Analyses were conducted separately for boys and girls. Probable interaction effects between age and weight dissatisfaction on communication with parents controlling for BMI were examined separately for boys and girls. In addition, interaction effects were examined between overweight status and weight dissatisfaction. A significance level of 0.05 was used for all statistical analyses and odds ratios were considered significantly different from 0 if 95% confidence intervals did not include 1.0.