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.