Prevalence of overweight and obesity and their association with hypertension and diabetes mellitus in an Indo-Asian population

Abstract

Background: The associations of body mass index (BMI) and chronic disease may differ between Indo-Asian and Western populations. We used Indo-Asian-specific definitions of overweight and obesity to determine the prevalence of these problems in Pakistan and studied the sensitivity and specificity of BMI cutoff values for an association with hypertension and diabetes mellitus.

Methods: We analyzed data for 8972 people aged 15 years or more from the National Health Survey of Pakistan (1990-1994). People considered overweight or obese were those with a BMI of 23 kg/m2 or greater, and those considered obese as having a BMI of 27 kg/m2 or greater. We built multivariable models and performed logistic regression analysis.

Results: The prevalence of overweight and obesity, weighted to the general Pakistani population, was 25.0% (95% confidence interval [CI] 21.8%-28.2%). The prevalence of obesity was 10.3% (95% CI 7.0%-13.2%). The factors independently and significantly associated with overweight and obesity included greater age, being female, urban residence, being literate, and having a high (v. low) economic status and a high (v. low) intake of meat. With receiver operating characteristic curves, we found that the use of even lower BMI cutoff values (21.2 and 22.1 kg/m2 for men and 21.2 and 22.9 kg/m2 for women) than those recommended for an Indo-Asian population yielded the optimal areas under the curve for an association with hypertension and diabetes, respectively.

Interpretation: A quarter of the population of Pakistan would be classified as overweight or obese with the use of Indo-Asian-specific BMI cutoff values. Optimal identification of those at risk of hypertension and diabetes and healthy targets may require the use of even lower BMI cutoff values than those already proposed for an Indo-Asian population.

Fig. 1: Receiver operating characteristic (ROC) curves for the sensitivity and specificity of the association between body mass index (BMI) and hypertension (A) and diabetes mellitus (B). For hypertension in men, the area under the curve (AUC) was 0.68 (95% confidence interval [CI] 0.66–0.69) and the optimal BMI cutoff value 21.2 kg/m² (triangle); this BMI value had a sensitivity of 61% and a specificity of 68%. The sensitivity and specificity were 43% and 82%, respectively, for a BMI cutoff value of 23 kg/m² and 28% and 90%, respectively, for one of 25 kg/m². For hypertension in women, the AUC was 0.66 (95% CI 0.65– 0.68) and the optimal BMI cutoff value 21.2 kg/m² (triangle); this value had a sensitivity of 65% and a specificity of 63%. The sensitivity and specificity were 50% and 76%, respectively, for a BMI cutoff value of 23 kg/m² and 37% and 85%, respectively, for one of 25 kg/m². For diabetes in men, the AUC was 0.64 (95% CI 0.63–0.66) and the optimal BMI cutoff value 22.1 kg/m² (triangle); this value had a sensitivity of 56% and a specificity of 72%. The sensitivity and specificity were 46% and 78%, respectively, for a BMI cutoff value of 23 kg/m² and 29% and 88%, respectively, for one of 25 kg/m². For diabetes in women, the AUC was 0.66 (95% CI 0.65–0.68) and the optimal BMI cutoff value 22.9 kg/m² (triangle); this value had a sensitivity of 59% and a specificity of 72%. The sensitivity and specificity were 59% and 73%, respectively, for a BMI cutoff value of 23 kg/m² and 42% and 82%, respectively, for one of 25 kg/m².