Spatial distribution of the risk for metabolic complications: an application in south-east Brazil, 2006–2007

Abstract

Objective: To identify spatial variation in the risk for metabolic complications (RMC) by means of a semi-parametric approach for multinomial data. Design: Cross-sectional study. Setting: We visited 730 households selected in the first of a two-stage sample in South health district in Campinas, São Paulo, Brazil, 2006-2007. Subjects: We interviewed 651 individuals and obtained their respective anthropometric measures and geographical coordinates of their house location. They were classified according to a combination of BMI and abdominal circumference as having no risk, increased, high or very high RMC. Results: Gender, age and schooling were associated with RMC. Crude spatial risk for the three levels of RMC in relation to the absence of risk suggested different patterns in each level. Adjusted spatial risk for the RMC showed smaller significant areas, but the pattern remained similar to crude risk. Conclusions: Spatial point analysis with a multinomial approach improves the understanding of differences in RMC found, as we could identify specific areas in which to intervene. The public health significance of these findings may lie in the additional evidence provided that spatial location and its features can influence patterns of RMC. Keywords Obesity Epidemiology Spatial risk Metabolic complicationsThe recent increase in the prevalence of obesity is widely recognized as constituting a major threat to health in most countries as obesity has reached epidemic proportions (4) . In Brazil in 2002-2003, the prevalence was 8?9 % for men and 13?1 % for women (5) . Although developed countries present higher levels of obesity, developing countries also show increasing overweight prevalence, mainly as a consequence of the nutrition transition they are experiencing (6) . Brazil has continental dimensions and inequality is present all over the country. Trends show a shift in the prevalence from the higher to the lower socio-economic level in Brazil (7) and this change has contributed to the coexistence of an overweight person with an underweight person in the same household, called the 'dual burden' of disease (8)(9)(10) .The number of studies on obesity has increased significantly in the last decade, mainly due to the high risk that this condition leads to patients with other chronic diseases, such as diabetes and hypertension (11)(12)(13) . Although several individual-level risk factors for obesity have been identified, population rates of obesity are determined by a complex interplay of biological, social, environmental, behavioural and cultural factors, which collectively have created over decades an adverse environment for maintaining a healthy weight. A comprehensive understanding of how these factors interact is currently lacking (14,15) . Age, sex, socio-economic status, sedentary lifestyle and co-morbidities such as diabetes and hypertension have traditionally been studied as risk factors for overweight or obesity. However, investigations on the risk of obesity and its association with factors other than...