Letter: Projection of Diabetes Prevalence in Korean Adults for the Year 2030 Using Risk Factors Identified from National Data (Diabetes Metab J 2019;43:90-6).

Using sex-specific forecasting models, Baik [1] expected the future prevalence of diabetes mellitus to be 29.2% in men and 19.7% in women in 2030 among the Korean population, which is surprisingly high considering the previous report from International Diabetes Federation (IDF) [2]. Even though Korea is one of the most rapidly aging countries and the elderly population ≥65 years old would increase by 2.3 times by 2030 compared with that of 2010 [3], the estimated prevalence may be too high considering that the number of Koreans aged ≥65 years is projected to be 24.3% in 2030 [3] and that the prevalence of diabetes in the 60s and ≥70s was 25.2% and 27.6%, respectively, in 2013 Korean National Health and Nutrition Examination Survey (KNHANES) [45]. The prevalence of diabetes increases with age and reaches the peak by the 60s and 70s; this was reported not only in the Korean population [67] but also worldwide [8]. IDF reported the group aged 65 to 79 years shows the highest diabetes prevalence in both women and men, which was about 18% to 20% [8]. The plateau of the prevalence of diabetes according to age in those >70s should be considered in the estimation of future diabetes prevalence in Korea.

Increasing prevalence of diabetes worldwide during the last decade might be not only from the increasing number of aging population but also from an increase in age-specific prevalence of diabetes [8]. In Korean adults, there have been changes in the gender- and age-specific prevalence of diabetes during the last decade; the prevalence of diabetes in the elderly population increased significantly, while this prevalence did not change significantly in young adults, especially in young women [5]. In addition, the contribution of each diabetic risk factor, such as obesity, β-cell dysfunction, sarcopenia, and socioeconomic status, in developing diabetes is also different according to gender, age, and survey year [91011]. Furthermore, there was a disparity in the trends of the prevalence of obesity according to sex and age in the Korean population [12]; in the case of young women (aged 20 to 59 years), the prevalence of obesity was decreased during the last decade [12], whereas women aged ≥60 years or men aged <60 years and ≥60 years showed an increasing prevalence of obesity during the same period [12]. Overall, it might be better to estimate the projection of diabetes prevalence separately in those aged 30 to 59 years and ≥60 years (or 30 to 64 years vs. ≥65 years).

The future prevalence of diabetes might be determined by both the number of aging population and the trend of age-specific prevalence of diabetes [8]. If we can separate the trend of both factors in the estimation of projection of diabetes prevalence, more efficient public health plans can be prepared for future diabetes epidemics.