In recent years, there has been rapid growth in the prevalence of diabetes, particularly in Asia. This region contains some of the most populous countries in the world, and has undergone pronounced demographic, epidemiologic, and socioeconomic change in recent decades [1]. Indeed, the prevalence of diabetes in Korea has increased from 1.5% to 9.9% in the past 40 years [2]. Bhowmik et al. [3] demonstrated a similarly significant rise in the prevalence of diabetes in Bangladesh, from 2.3% in 1999 to 7.9% in 2009. This rapid increase was attributed to the dramatic socioeconomic and lifestyle changes accompanying urbanization in rural Bangladeshi communities; however, these changes were not well documented. If it is possible, demonstrating changes of dietary habits, exercise and occupation during study period may make the present finding more reliable.

Secondly, although waist-hip ratio (WHR) was a significant risk factor for diabetes in men, the odds ratio (OR) for WHR was significant in women only in 2009. This may be due to the small number of subjects with WHR <0.8, which is a reference group in women. It may be more useful to divide WHR into <0.8, 0.8 to 0.9, ≥0.9 as the authors did for body mass index. Alternatively, the OR of waist circumference rather than WHR could be used to present the importance of central obesity.

Lastly, it is unclear why the prevalence of hypertension showed a decreasing trend over the follow-up period. Increased awareness and treatment of hypertension may not be responsible for this finding, since it can improve blood pressure level and overall health in patients with hypertension, but does not affect the documented prevalence of hypertension. It may also be important to check the method of blood pressure measurement to exclude systematic error. As the authors indicated, longitudinal data obtained from a nationally representative sample may present more reliable results for the prevalence of hypertension.