Lower BMI Cutpoints Predict Diabetes and Hypertension in Asians

Researchers say evidence pooled from 34 studies suggests Asians with a BMI of 23 or higher should be considered overweight, and those with a BMI of 25 or higher should be considered obese.

In comparison, the World Health Organization's international cutpoints for overweight and obesity are 25 and 30, respectively. The lower cutpoints for Asian patients are associated with elevated risks of hypertension and type 2 diabetes, but not total mortality.

Dr. Youfa Wang and colleagues at Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland identified the 34 papers in a PubMed search for Asian cohort studies on type 2 diabetes, hypertension and total mortality. They generally chose studies that included more than 1000 adults and had more than four years of follow up, but the mortality studies had more than 5000 adults and five or more years of follow up.

Seventeen studies supported lower than usual cutpoints. Nine of 14 supported lower cutpoints for type 2 diabetes, five out of six for hypertension, and three out of 18 for total mortality.

At a BMI of 23 or higher, pooled relative risks were 1.33 for hypertension and 1.73 for type 2 diabetes. At a BMI of 25 or higher, those pooled relative risks rose to 1.62 hypertension and 3.21 for type 2 diabetes.

Dr. Wang stated that there was no significant association with total mortality at those cutpoints, except for mortality in non-smokers at BMI 25 or higher, for which the relative risk was 1.27.

"Our study will not settle the debate on whether Asians should use reduced cutpoints, but it provides some very good evidence showing that the conclusions can be different if based on total mortality or morbidity alone."

In light of the findings, Dr. Wang suggests that certain regions develop common cutpoints that differ from the WHO's standard, rather than making them country-specific.

This systematic review indicates that Asian patients should be screened at lower BMI to help prevent, diagnose, and treat hypertension and diabetes. Should we also look at other ethnic groups?

Presented at the Obesity Society's annual meeting in Orlando, Florida. Oct. 2011