The relationship between lifestyle, social characteristics and obesity in 3-year-old Japanese children

It has been observed that obese children receive genetic and environmental effects that are associated with them being overweight. With regard to the latter, lifestyles such as eating habits and physical activity have been fo cused on. In the present study, the social characteristics which would domi nate their lifestyles were investigated: as background variables. For this purpose, 9668 Japanese children aged three years who were all born in Toyam a prefecture, Japan, in 1998, served as birth cohort subjects. For the comp arison between obese (Kaup index; mass in kg/(height in m)(2) greater than or equal to 18) and nonobese (Kaup index < 18) children, irregular snack in take, physical inactivity and reduced sleeping hours were chosen as statist ically significant obesity-related lifestyle indicators for the children. F or social characteristics, family construction (expanded family with grandp arents/nonexpanded family), main caregiver (mother/other), attending a nurs ery school (yes/no) and mother's employment (full-time worker/other) were c hosen. These were significantly associated with the obesity-related lifesty les mentioned above using multiple logistic regression analysis adjusted fo r other variables of social characteristics as well as for gender and birth month (July-December/January-June). The two greatest population-attributab le risk percentages were observed for mother as main caregiver (-36.5%) and attending a nursery school (-28.9%) for irregular snack intake. Therefore, these two social characteristics substantially reduced the number of child ren with irregular snack Intake. On the other hand, the two social characte ristics were reversed in children with reduced sleeping hours (population-a ttributable risk percentage of mother as main caregiver: 15.4%; attending a nursery school: 17%). In contrast with favourable effects on snack intake these social characteristics showed an adverse influence on the sleeping ha bits of children.