National Prevalence of Obesity Prevalence of obesity in Thailand See editorial on pp. 587–588. W. Aekplakorn 1 and L. Mo-suwan 2 1 Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok; 2 Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand Received 21 April 2009; revised 5 May 2009; accepted 15 May 2009 Address for correspondence: W Aekplakorn, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Rama 6 Road, Rajdevi, Bangkok 10400, Thailand. E-mail: rawap@mahidol.ac.th Summary The prevalence of obesity in Thailand has been doubled in the past two decades. Data from three consecutive National Health examination surveys (NHES) have shown a secular trend, as the prevalence of obesity with body mass index 25 kg m -2 in adults increased from 13.0% in men and 23.2% in women in 1991 to 18.6% and 29.5% in 1997 and 22.4% and 34.3% in 2004 respectively. Obesity prevalence in children, using weight for height criteria, increased from 5.8% in 1997 to 7.9% in 2001 for the 2–5-year-olds and from 5.8% to 6.7% for the 6–12-year-olds. The data also show disproportionate increases of obesity in the rural area, which indicates the problem no longer restricts to the higher socioeconomic group. Keywords: National Survey, obesity, prevalence, Thailand. obesity reviews (2009) 10, 589–592 Prevalence of obesity The prevalence of obesity in Thailand, as in other countries with fast growing economy, has been increasing in an alarming rate. In Thailand, a series of National Health Examination Survey were conducted consecutively in 1991, 1997 and 2004. Each survey was a national representative cross-sectional survey. The present study reports on evi- dence of secular trend of obesity in Thailand using data from National Health Examination Survey I–III (1,2). These surveys were mainly targeted on adult population; however, the second survey also included a sample of chil- dren population. The data on measurements of weight and height provide an opportunity to examine the trends of obesity in Thai population. All the surveys used standardized measurement of anthropometry at time of the survey period. Overall, age- adjusted mean body mass index (BMI) in Thai adults aged 18 years increased from 22.0 kg m -2 in 1991 to 22.7 kg m -2 in 1997 and 23.2 kg m -2 in 2004. This suggests that the distribution of weight and BMI of the entire popu- lation is shifted to the right. The prevalence rates of obesity were determined using BMI cut-off points at 25 kg m -2 (3) and 30 kg m -2 (4). The prevalence of obesity with BMI  25 kg m -2 in adults increased dramatically from 18.2% in 1991 to 24.1% in 1997 and 28.1% in 2004. For those with BMI  30 kg m -2 , the prevalence increased from 3.5% to 5.8% and 6.9% in the corresponding years (2). Overall, the prevalence was higher in women than in men especially in the middle-age group. The prevalence of obesity with BMI  25 kg m -2 increased in both sex, from 13.0% in men and 23.2% in women in 1991 to 18.6% and 29.5% in 1997 and 22.4% and 34.3% in 2004 respectively. Figure 1 shows trends in obesity over the last two decades, the prevalence has been increasing in all age groups. The highest prevalence rates of obesity with BMI  25 and 30 kg m -2 were in the 45–54 years age group in both men and women. More importantly, the largest increase for BMI  25 kg m -2 was in the 18–34 age group with almost double increases in men and women. obesity reviews doi: 10.1111/j.1467-789X.2009.00626.x 589 © 2009 The Authors Journal compilation © 2009 International Association for the Study of Obesity. obesity reviews 10, 589–592