Decreasing trends of the prevalence of diabetes and obesity in Korean women aged 30-59 years over the past decade: results from the Korean National Health and Nutrition Examination Survey, 2001-2010.

The prevalence of diabetes in South Korea reached 9 to ∼10% in adults aged ≥30 years and remained stable in the 2000s (1,2). Even though the Korean population is rapidly aging, the proportion of the elderly population aged ≥65 years has been increasing over the past 10 years from 7.2% of the total population in 2000 to 11.0% in 2010 (3). We investigated the change in the prevalence of diabetes in Korean adults aged ≥30 years with respect to age, using data from the Korean National Health and Nutritional Examination Survey (KNHANES) 2001–2010. Subjects with diabetes were defined as users of antidiabetic medication, including insulin, at the point of the survey or as individuals with an 8-h fasting plasma glucose level ≥126 mg/dL. Direct age standardization of the data was performed, using the Korean population aged ≥30 years in 2010 as the standard, and survey logistic regression and survey linear regression applying age standardization were used for trend analysis by survey year.

The crude prevalence of diabetes in adults aged ≥30 years was 10.6% (SE 0.6%) in 2001 and 10.2% (0.5%) in 2010 (Table 1). Even after adjusting for the age structure of the Korean population in 2010, there was no significant change during that period (P = 0.901). We performed the subsequent analysis by age group within each sex. Women in their 30s, 40s, and 50s showed a decreasing trend of the prevalence of diabetes, and the prevalence of diabetes in women aged 30–59 years decreased significantly from 6.9% in 2001 to 4.5% in 2010 (P = 0.031) (Table 1). After adjusting for BMI, a trend was maintained in women aged 30–59 years (P = 0.073). In contrast, the prevalence of diabetes in men did not changed except in those aged ≥60 years, which increased from 15.9% in 2001 to 21.6% in 2010 (P = 0.025).

Table 1

The prevalence of diabetes among Korean adults aged ≥30 years in the KNHANES, 2001–2010

In women aged 30–59 years, BMI (from 23.7 [0.1] kg/m2 in 2001 to 23.3 [0.1] kg/m2 in 2010, P = 0.004) and waist circumference (from 78.9 [0.2] cm in 2001 to 77.5 [0.3] cm in 2010, P = 0.008) decreased significantly during that period. Women exhibited a significant decrease in total daily energy intake (P < 0.001) and a significant increase in the proportions of women performing regular exercise, which was defined as those who exercised ≥30 min/day and ≥3 times a week, regardless of intensity from 11.5% (0.7%) in 2001 to 26.8% (1.3%) in 2010 (P < 0.001). In contrast, BMI in men aged 30–59 years increased significantly from 24.0 (0.1) kg/m2 in 2001 to 24.3 (0.1) kg/m2 in 2010 (P = 0.002).

In conclusion, the prevalence of diabetes among women aged 30–59 years showed a decreasing trend from 2001 to 2010. The reduction of obesity along with lifestyle improvements might be the causes of these changes.