Effects of Neighbourhood Income on Reported Body Mass Index: An Eight Year Longitudinal Study of Canadian Children

Background:This study investigates the effects of neighbourhood income on children's BodyMass Index (BMI) from childhood (ages 2–3) to early adolescence (ages 10–11) using longitudinaldata.Methods:Five cycles of data from the Canadian National Longitudinal Survey of Children andYouth are analyzed for a sub-sample of children (n = 2152) aged 2–3 at baseline (1994) and assessedat two year intervals to 2002. Body mass index percentiles are based on height/weight estimatesreported by proxy respondents (child's person most knowledgeable). Family and neighbourhoodfactors were assessed at baseline. The prevalence of neighbourhood low income was obtained fromthe 1996 Census and divided into three categories from 'most poor' to 'least poor'. Longitudinalmodelling techniques were applied to the data.Results:After controlling for individual/family factors (age, sex, income, education, familystructure) living in the 'most poor' neighbourhood was associated with increasing BMI percentile(1.46, 95% CI 0.16 to 2.75) over time compared to a 'middle' income neighbourhood. Living in anurban (vs. rural) neighbourhood was associated with a decreased BMI percentile (-3.57, 95% CI -6.38 to -0.76) across all time periods.Conclusion:These findings provide evidence that effects of neighbourhood disadvantage onchildren's BMI occur between childhood and early adolescence and suggest that policies shouldtarget the conditions of childhood, including the neighbourhood environment.