EFFECT OF AGING ON HBA(1C) IN A WORKING MALE JAPANESE POPULATION

OBJECTIVE - To evaluate whether there is any change in HbA(1c) determi ne the effects of body mass index (BMI), exercise, and family history of diabetes on this change. RESEARCH DESIGN AND METHODS - A cross-sect ional survey of 7,664 male Japanese workers aged 20-59 years was perfo rmed. All subjects received a physical examination that included measu rement of HbA(1c) as an indicator of plasma glucose level. The subject s were classified according to their ages and BMIs, and any relationsh ip with HbA(1c) levels was evaluated. Information on physical activity and family history of diabetes was obtained by a questionnaire. RESUL TS - In all BMI groups, HbA(1c) increased with age. The greatest incre ase in HbA(1c) was observed in the 40- to 49-year-old age-group in sub jects with a BMI less than or equal to 26 kg/m(2) and in the 30- to 39 -year-old age-group in subjects with a BMI >26. HbA(1c) in the subject s aged 20-29 years did not change with BMI. In contrast, HbA(1c) in su bjects aged 30-59 years was significantly higher in those with a BMI > 26 when compared with those with BMI less than or equal to 20. The age -dependent increase in HbA(1c) was greater in subjects with a positive rather than negative family history of diabetes. This age-dependent i ncrease was not affected by active participation in sporting activitie s of mild to moderate intensity for 3 or more days per week. CONCLUSIO NS - The age-dependent increase in HbA(1c) may be a consequence of the aging process itself. Furthermore, both BMI and a hereditary predispo sition to diabetes, but not active participation in sports, affect thi s age-dependent increase in HbA(1c).