Abstract
There is a relationship between childhood obesity and area-level deprivation. While the New Zealand Index of Deprivation (NZDep) has been used widely in research for the past 20 years, the Index of Multiple Deprivation (IMD) was released in 2017. This study aims to investigate the association between deprivation and childhood obesity in New Zealand and compare measures of deprivation.
Data from 316 794 4-year-olds in New Zealand undertaking the B4 School Check in 2010 to 2016, a national health and development screen, were analysed. Multilevel logistic regression models assessed the relationship between area-level deprivation and individual-level child obesity. Models were adjusted for age, sex, immigration status, ethnicity, and year. Deprivation was measured using the census-based NZDep2013 (deciles) and the administrative data-based IMD (deciles). The seven domains of the IMD were also considered.
The relationship between deprivation and obesity was very similar for the IMD and NZDep2013, point estimates were near identical, and confidence intervals overlapped substantially. Higher levels of deprivation were associated with a higher prevalence of child obesity. The relationship between deprivation and child obesity varied considerably across IMD domains. The education domain had the strongest association with child obesity and had an association with child obesity independent of the other domains of deprivation.
Overall, there was little difference between the NZDep and IMD. However, the IMD's domains and IMD-1 approach reveal more nuanced understandings of the deprivation-obesity gradient, including the importance of area-level education deprivation for predicting child obesity rates.