Background: Although the prevalence of the metabolic syndrome (MetS) has been well-documented in Western Caucasian populations, there are few studies in non-Caucasian populations. The objectives of the present study were to estimate the prevalence of MetS and to find an optimal BMI cut-off value for defining obesity in the Thai population.

Material and Method: A sample of 307 men and 295 healthy women aged between 20 and 90 years (average age of 45 years) who came for a health check-up clinic in Khon Kaen, a northeast province of Thailand, were studied. The present study was conducted between 2003 and 2004. The modified ATP III criteria were used to estimate the age-and-sex specific prevalence of MetS, in which a BMI of ≥27 kg/m² for men and 25 kg/m² for women were used in place of waist circumference. In the Thai population, these BMI cut-offs were equivalent to a percent body fat of 25% and 35% in men and women respectively.

Results: The overall prevalence of MetS was 15%, with no significant differences between men (15.3%) and women (14.6%). In men, the prevalence increased from 9.5% among the 20-39 age group to 24.7% among the 50+ age groups. In women, the respective prevalence was 7% and 29.5%. When BMI was removed from the classification of MetS, the overall prevalence of “MetS-without-BMI” (still defined by the presence of at least 3 abnormalities) in both men and women was 7.8%. However, the prevalence of MetS-without-BMI increased with higher BMI levels: among those with BMI <25, the prevalence was 4.6% in men and 5.0% in women; among those with BMI ≥25, the prevalence was 13% in men and 16% in women.

Conclusion: The prevalence of MetS in this semi-rural Thai population was 15%, which is as common as in Caucasian populations. In the Thai population, obesity was a major component of MetS.

Keywords: Metabolic syndrome, Body mass index, Body weight, Prevalence, Thai, Epidemiology