Obesity and its Relation With Diabetes and Hypertension: A Cross-Sectional Study Across 4 Geographical Regions

Abstract

Background: The implications of rising obesity for cardiovascular health in middle-income countries has generated interest, in part because associations between obesity and cardiovascular health seem to vary across ethnic groups.

Objective: We assessed general and central obesity in Africa, East Asia, South America, and South Asia. We further investigated whether body mass index (BMI) and waist circumference differentially relate to cardiovascular health; and associations between obesity metrics and adverse cardiovascular health vary by region.

Methods: Using baseline anthropometric data collected between 2008 and 2012 from 7 cohorts in 9 countries, we estimated the proportion of participants with general and central obesity using BMI and waist circumference classifications, respectively, by study site. We used Poisson regression to examine the associations (prevalence ratios) of continuously measured BMI and waist circumference with prevalent diabetes and hypertension by sex. Pooled estimates across studies were computed by sex and age.

Results: This study analyzed data from 31,118 participants aged 20 to 79 years. General obesity was highest in South Asian cities and central obesity was highest in South America. The proportion classified with general obesity (range 11% to 50%) tended to be lower than the proportion classified as centrally obese (range 19% to 79%). Every standard deviation higher of BMI was associated with 1.65 and 1.60 times higher probability of diabetes and 1.42 and 1.28 times higher probability of hypertension, for men and women, respectively, aged 40 to 69 years. Every standard deviation higher of waist circumference was associated with 1.48 and 1.74 times higher probability of diabetes and 1.34 and 1.31 times higher probability of hypertension, for men and women, respectively, aged 40 to 69 years. Associations of obesity measures with diabetes were strongest in South Africa among men and in South America among women. Associations with hypertension were weakest in South Africa among both sexes.

Conclusions: BMI and waist circumference were both reasonable predictors of prevalent diabetes and hypertension. Across diverse ethnicities and settings, BMI and waist circumference remain salient metrics of obesity that can identify those with increased cardiovascular risk.

Figure 1

Prevalence of central and general obesity by sex. Central obesity is classified based on waist circumference, and general obesity (international and ethnic-specific cut points) is classified based on BMI. The error bars mark the 95% confidence interval of the prevalence.

Figure 2

Associations between BMI, kg/m², (left panels) and waist circumference, cm, (right panels) and prevalent cardiovascular risk factors among adults aged 40–69 years. The circle marks the prevalence ratio estimate for men and the square the estimate for women; the dashed vertical line shows the null value. BMI and waist circumference were standardized to have mean=0 and SD=1 in order to compare.

Figure 3

Associations of BMI, kg/m², and waist circumference, cm, with diabetes and hypertension in each region. The dashed vertical line shows the null value.

Figure 4

Associations of BMI, kg/m², and waist circumference, cm, with diabetes and hypertension in each age group. The p-value is from the test for a linear trend across age groups. The dashed vertical line shows the null value.