Clustering patterns of obesity-related multiple lifestyle behaviours and their associations with overweight and family environments: a cross-sectional study in Japanese preschool children

OBJECTIVES: The purpose of this study is (1) to identify obesity-related lifestyle behaviour patterns of diet, physical activity, sedentary and sleep behaviours in preschool children, (2) to examine the association between identified behaviour clusters and overweight/obesity and (3) to investigate differences in children's family environments according to clusters. DESIGN SETTING AND PARTICIPANTS: A cross-sectional study on 2114 preschool children aged 3–6 years who attended childcare facilities (24 nursery schools and 10 kindergartens) in Tsuruoka city, Japan in April 2003 was conducted. MAIN OUTCOME MEASURES: Children's principal caregivers completed a questionnaire on children's lifestyle behaviours (dinner timing, outside playtime, screen time and night-time sleep duration), family environment (family members, maternal employment, mealtime regularity and parents' habitual exercise and screen time) and measurements of weight and height. Cluster analysis was performed using children's 4 lifestyle behaviours based on those non-missing values (n=1545). The χ(2) tests and analysis of variance (ANOVA) estimated cluster differences in overweight/obesity and family environments. RESULTS: 6 clusters were identified. Children's overweight/obesity varied across clusters (p=0.007). The cluster with the most screen time, shorter night-time sleep duration, average dinner timing and outside playtime had the highest overweight/obesity prevalence (15.1%), while the cluster with the least screen time, the longest sleep duration, the earliest dinner timing and average outside playtime had the lowest prevalence (4.0%). Family environments regarding mealtime regularity and both parents' screen time also significantly varied across clusters. The cluster having the highest overweight/obesity prevalence had the highest proportion of irregular mealtimes and the most screen time for both parents. CONCLUSIONS: This study suggests that public health approaches to prevent children's overweight/obesity should focus on decreasing screen time and increasing night-time sleep duration. To shape those behaviours, regular mealtimes and decreasing parents' screen time within family environments need to be targeted among family members.