The Epidemiologic Transition of Diabetes Mellitus in Taiwan: Implications for Reversal of Female Preponderance from a National Cohort

Abstract

Diabetes prevalence studies show a female preponderance, especially in developed countries. This review summarizes the epidemiologic evidence for a possible transition in sexual preponderance in Taiwan. Major epidemiologic surveys of diabetes prevalence and studies on the incidence and mortality of diabetes in Taiwan over the past decades were reviewed. Diabetes prevalence increased from 5.1% in 1970 to 12.8% in 1996 with female preponderance. However, a 3-fold higher prevalence in men in the younger age of 19-44 years in contrast to a female preponderance in the older age was observed in the 1996 survey. The female preponderance could possibly be explained by a higher mortality due to higher prevalence of macrovascular complications and higher incidence of hypertension in the diabetic men. Although overall incidence of diabetes was higher in women (218.4 vs 187.1 per 100,000), age-specific incidence analyses sug- gested a higher incidence accompanied by obesity in men in the age groups below 45 years. In conclusions, increasing prevalence of diabetes with female preponderance had been observed for decades in Taiwan, which can be explained partly by the higher risk of morbidity and mortality in the diabetic men and an overall higher incidence in women of all ages. However, the sex preponderance in diabetes is expected to change from women to men rolling from the past decades to the future in Taiwan because of the increasing prevalence of obesity in the younger men. two factors. A close observation of the secular trends in the epidemiologic transition of such a chronic and health damag- ing disease is important for both the policymakers and clini- cal practitioners to take early measures in the prevention and treatment of the disease. To answer a series of these interrelated epidemiologic questions, it would be better if all data could be obtained from a large cohort of diabetic patients representative at a national level. The National Health Insurance (NHI) program in Taiwan is a unique and compulsory health care system which covers more than 96% of the total population. Only those who are serving in the military or subject to criminal sanction, etc. would be exempt from this program. A sys- tematic use of the data obtained from a cohort of diabetic patients within this health care system has been conducted since the implementation of the NHI in 1995. Therefore it is the purpose of this review to give a general description of the data and interpretation of the implications introduced by a series of epidemiologic analyses from the established NHI diabetes cohort along with the vital statistics and the series of prevalence surveys in this country over the past decades.