Objective This study aims to describe the relationship between body mass index (BMI) and blood pressure in three distinct Peruvian populations. Methods Three population groups were recruited: Rural (born and remained in Ayacucho), Migrant (born in Ayacucho and migrated to Lima), and Urban (born in Lima). Systolic blood pressure (SBP) and diastolic blood pressure were measured using oscillometric devices (Omron M5-i, Japan) and standardised techniques. BMI was calculated from standardised measurements. ANOVA was used to test differences between groups. Multi-variable linear regression was used to describe the relationship between BMI and blood pressure, adjusting for potential confounders. Results SBP was similar in the rural (120.9618.7) and migrant groups (119.9616.4), but higher in the urban group (128.2622.9). BMI was significantly lower in the rural group (23.262.7), but similar in the migrant (27.064.3) and urban groups (28.365.4). There was a positive relationship between BMI and SBP (slope 0.81; 95% CI 0.59 to 1.03) after adjustment for age, sex, height and haemoglobin. A positive relationship was observed in urban residents (0.61; 0.04e1.18), but the gradient of the relationship was steeper in the migrant group (0.75, 0.48e1.02). Similar results were found for diastolic blood pressure. Conclusions The relationship between BMI and blood pressure differed between our three study populations, with blood pressure rising at lower values of BMI in migrants. Migrant population in transitional countries may be at greater risk of developing hypertension, and the effect of BMI as a predictor is not uniform in migrant and urban-born residents. Background Prevalence of cardiovascular disease and the risk factors associated with it are increasing globally and in particular throughout the developing world. The south Asian region is especially at risk because of the increasing prevalence of the said risk factors. The study was undertaken to investigate the impact of social class and area of residence in distribution of cardiovascular risk factors mainly hypertension and diabetes mellitus in Pakistan. Methods A cross-sectional study on 2495 subjects aged between 30 and 75 years was conducted in the Punjab province covering both the urban and rural areas. A detailed questionnaire was completed; anthropometric measurements and blood samples from the chosen subjects were taken after a written informed consent was obtained. Participants were categorised into urban and rural, and assigned a social class by occupation. A logistic regression model was used to explore the association between social class and the area of residence Results Overall prevalence of hypertension and diabetes was 24.21% and 16.63% respectively. Out of the total number of participants, 56.79% (n¼1417) were rural area residents while 43.21% (n¼1078) were urban. Urban individuals appeared significantly more likely (p<0.001) to be hypertensive (OR¼3.03, 95% CI 2.41 to 4.82) and more likely (p<0.001) to be diabetic (OR¼1.77, 95% CI 1.37 to 2.29) than rural ...