Cut‐off Point of BMI and Obesity‐Related Comorbidities and Mortality in Middle‐Aged Koreans

Objective : The need for a lower BMI to classify overweight in Asian populations has been controversial. Using both disease and mortality outcomes, we investigated whether lower BMI cut‐off points are appropriate for identifying increased health risk in Koreans. Research Methods and Procedures : We conducted a cohort study among 773, 915 men and women from 30 to 59 years old with 8‐ to 10‐year follow‐up periods. Primary outcomes were change of obesity prevalence, obesity‐related disease incidence, and all‐cause mortality. Results : Prevalence of overweight (BMI of 25.0‐29.9) has steadily increased (1.3% annually), whereas obesity (BMI ≥ 30) showed a lower prevalence and only a slight increase (0.1%‐0.2% annually). Our study revealed that dose‐response relationships exist between obesity and related disease incidences (hypertension, type 2 diabetes, and hypercholesterolemia) beginning at lower BMI levels than previously reported. Compared with those in the healthy weight range, Koreans with a BMI ≥ 25 were not at greater risk of hypertension, type 2 diabetes, or hypercholesterolemia than has been reported for whites in similar studies. Obesity‐related all‐cause mortality also did not seem so different from that of whites. Discussion : Our findings did not support the use of a lower BMI cut‐off point for defining overweight in Koreans compared with whites for the purpose of identifying different risks. However, populations with BMI ≥ 25 are rapidly increasing and have substantial risks of diseases. To preempt the rapid increases in obesity and related health problems that are occurring in Western countries, Korea should consider using a BMI of 25 as an action point for obesity prevention and control interventions.