[Individual social characteristics, municipal environment and the prevalence of weight problems in early childhood: a multilevel analysis].

BACKGROUND: Few studies have examined the prevalence of weight problems before the age of 5 years although this period is critical in the development of obesity. An inverse association between socio-economic status and weight problems is well documented in adult women but not for young children. Similarly several studies of adults and adolescents or older children show that the prevalence of weight problems is associated with the level of deprivation of the neighbourhood environment and the degree of urbanization, independent of social individual factors, even though this has not been examined for young children.

METHODS: We evaluated prevalence rates of weight problems in children aged 3.5-4.5 years in southeastern France and their association with both individual social factors and municipal environment characteristics. Random stratified cluster sampling allowed us to select 112 nursery schools. Physicians from the early childhood protective services conducted a mandatory medical examination and collected data with a new questionnaire (EVALMATER), developed to standardise these examinations. Overweight and obesity were defined by international references after calculation of each child's BMI (kg/m(2)). We constructed a social disadvantage index to assess characteristics of the municipalities where the nursery schools were located and used multilevel analysis to study the associations of municipal characteristics (the disadvantage index and a urban/rural classification of the municipalities) with weight problems independently of individual socio-economic variables.

RESULTS: The study included 2495/2959 (84.3%) children, with a mean age of 3.9+/-0.3 years. The prevalence of overweight was 8.2% (CI95%=7.1-9.3) and that of obesity 2.1% (CI95%=1.5-2.7). Prevalence of obesity was significantly higher in girls, only children, those who had not attended day-care before nursery school, whose mother was not employed, or whose father was not a white-collar-worker. Independently of these variables, it was also significantly higher among children who lived in urban areas or deprived municipalities. None of these factors were found associated with overweight alone.

CONCLUSION: Actions of prevention in France should target parents of young children.