The association between area-based deprivation and change in body-mass index over time in primary school children: a population-based cohort study in Hampshire, UK.

Abstract

Childhood obesity is a serious public health challenge. Cross-sectional evidence indicates that childhood obesity is strongly linked to area deprivation level, yet longitudinal research is scarce. We assessed the association of home-based and school-based deprivation indices with change in childhood body-mass index (BMI) z-score and BMI status over 6 years in Hampshire, England. This longitudinal study linked the National Child Measurement Programme data for children aged 4-5 years (2007-08 to 2009-10) to 10-11 years. The dataset was stratified into two groups: 18,733 children for whom home deprivation quintiles, according to the Index of Multiple Deprivation (IMD), remained constant, and 6153 children who moved home deprivation quintiles between the two time points. The associations between IMD quintiles and change in BMI z-score and status were analysed. 63.7% of children remained a healthy weight, 3.1% remained overweight, 5.3% remained with obesity, 8.3% became overweight, and 10.3% developed obesity. Children living in the most deprived quintile increased their BMI z-score by 0.13 units more than those in the least deprived quintile (95% CI: 0.08-0.19). Home-based deprivation displayed associations with change in BMI status. (Relative risk for the most deprived quintile: become overweight 1.47, 1.21-1.78, remain obese 1.82, 1.34-2.40, become obese 2.07, 1.73-2.48.) School-based deprivation was not associated with change in BMI z-score or BMI status. Moving home to a more deprived quintile was associated with developing obesity (1.22, 1.04-1.43). More children living in deprived areas developed obesity over time. Home-based deprivation level is more strongly associated with adverse change in childhood weight than school-based deprivation. Scholarly settings can provide opportunities for interventions, however obesity prevention interventions should tackle the obesogenic environment combining family and area-based measures.