Understanding neighbourhood retail food environmental mechanisms influencing BMI in the Caribbean: a multilevel analysis from the Jamaica Health and Lifestyle Survey: a cross-sectional study.

Objective To derive estimates of the associations between measures of the retail food environments and mean body mass index (BMI) in Jamaica, a middle-income country with increasing prevalence of obesity. Design Cross-sectional study. Setting Data from the Jamaica Health and Lifestyle Survey 2008 (JHLS II), a nationally representative population-based survey that recruited persons at their homes over a 4-month period from all 14 parishes and 113 neighbourhoods defined as enumeration districts. Participants A subsample of 2529 participants aged 18–74 years from the JHLS II who completed interviewer-administered surveys, provided anthropometric measurements and whose addresses were geocoded. Primary outcome measure Mean BMI, calculated as weight divided by height squared (kg/m2). Results There was significant clustering across neighbourhoods for mean BMI (intraclass correlation coefficients=4.16%). Fully adjusted models revealed higher mean BMI among women, with further distance away from supermarkets (β=0.12; 95% CI 8.20×10−3, 0.24; p=0.036) and the absence of supermarkets within a 1 km buffer zone (β=1.36; 95% CI 0.20 to 2.52; p=0.022). A 10 km increase in the distance from a supermarket was associated with a 1.7 kg/m2 higher mean BMI (95% CI 0.03 to 0.32; p=0.020) in the middle class. No associations were detected with fast-food outlets or interaction by urbanicity. Conclusions Higher mean BMI in Jamaicans may be partially explained by the presence of supermarkets and markets and differ by sex and social class. National efforts to curtail obesity in middle-income countries should consider interventions focused at the neighbourhood level that target the location and density of supermarkets and markets and consider sex and social class-specific factors that may be influencing the associations.