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 > or = 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 > or = 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 > or = 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.