Background

The dietary behaviours of adolescents are likely to play an important role in the development of a range of chronic health conditions including overweight and obesity. The family environment has been identified as a critical context for the development of eating behaviours. The influence of family circumstance (e.g. parental marital status, parental education level, parental employment status, sibling status) on adolescents’ food habits/choices has not been comprehensively explored, yet such characteristics may impact adolescent behaviours by influencing their daily home environment. Previous studies have focused on single components of family circumstance (e.g. parental education level), which limits the ability to compare the influence of different aspects of family circumstance on dietary behaviour across studies (due to different samples and methodologies). It is important to consider the influence of multiple indicators of family circumstance on eating behaviour in the same sample of adolescents, using the same methodology, because differential associations may point to different underlying pathways. The purpose of this study was to examine the influence of multiple indicators of family circumstance on adolescent dietary behaviours and changes in dietary behaviours over a two year period.

The Youth Eating Patterns study

The Youth Eating Patterns (YEP) study is a longitudinal study of dietary behaviours among adolescents in Melbourne, Australia. All co-educational state (government) and Catholic secondary schools (Years 7 to 12) with enrolments over 200, located in the southern metropolitan region of Melbourne and the non-metropolitan region of Gippsland, to the east of Melbourne, were invited to participate in the study. All students (n = 9,842) from Year 7 (aged 12-13 years) and Year 9 (aged 14-15 years) from participating schools were invited to complete the online survey at baseline. Teachers distributed parental consent forms via students asking permission for their child to participate in the study. The consent form also asked parents to provide information about their family circumstances (e.g., marital status, education level, employment status, number of children). Parental consent was obtained for 4,502 (46% of all eligible students). The YEP survey is an online food habits survey and was administered by teachers during a class when students had access to computers. The survey was administered during 2004 and 2005 (baseline, T1), and again two years later in 2006 and 2007 (follow-up, T2). At baseline, 3,264 adolescents completed the YEP survey. Final analyses were conducted with 1,884 adolescents (55% girls, mean age 13.2 years) who had completed the YEP survey at baseline and at the two-year follow-up.

Adolescent dietary behaviour by gender and age

At baseline, a higher proportion of adolescent girls, compared to boys, skipped breakfast, and were high Fruit and Vegetable (F&V) consumers. At baseline, a higher proportion of Year 9 students, compared to Year 7 students, skipped breakfast. A higher proportion of Year 7 students, compared to Year 9 students, were high F&V consumers.

The majority of participants did not change their dietary behaviours over the two-year period. A higher proportion of adolescent girls, compared to boys, increased their frequency of breakfast skipping. A higher proportion of adolescent boys, compared to girls, increased their snack and fast food consumption.

Targeting maternal education…

Generally maternal education was more consistently associated with positive dietary behaviour as well as positive changes in dietary behaviour than any other indicator of family circumstance. There was no consistency in the associations between gender and our predictor and outcome variables, suggesting that family circumstance differentially influences the dietary behaviours of males and females.

At baseline, compared to adolescent boys whose mothers had a low level of education, those whose mothers had a high level of education were less likely to skip breakfast and those whose mothers had a medium level of education were less likely to have low vegetable consumption.

Among boys and girls, compared to those whose mothers had low education levels, those with mothers who had high education levels were less likely to increase their breakfast skipping. Compared to those whose mothers had low education levels, adolescent boys whose mothers had medium education levels were more likely to decrease their snack consumption and adolescent girls whose mothers had high levels of education were less likely to increase their snack consumption.

… to improve adolescent dietary behaviour

This study highlights the complexity of relationships between family circumstance and adolescent dietary behaviours. Interventions aimed at promoting healthy eating among adolescents that include a family component have shown positive results in the past. Future research needs to target the family environment and assess the efficacy of strategies promoting maternal nutritional knowledge on the dietary behaviours of adolescents.