[Associations between glycated hemoglobin levels and atherosclerotic risk factors in urban communities]

Abstract

Purpose: To prevent coronary heart disease and type 2 diabetes mellitus, we need to focus on "the deadly quartet" (coexistence of upper-body obesity, glucose intolerance, hypertriglyceridemia, and hypertension), and the multiple risk factor syndrome related to insulin resistance. As few urban community-based population studies have evaluated the correlation between glycated hemoglobin A1c (HbA1c) levels and risks of life-style related disease, we investigated this parameter and its correlation with atherosclerotic risk factors in participants of health check ups in two communities in Kanagawa prefecture. We also examined whether these correlations were affected by difference between the two groups.

Methods: The study populations comprised male and female residents aged 40-79 in two communities (A and B cities) in 1998. Age, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), HDL-cholesterol (HDL-C), triglycerides (TG), GOT, GPT, Uric acid (UA), and gamma GTP were considered as atherosclerotic risk factors. Firstly we calculated correlation coefficients with HbA1c level. Secondly, logistic regression analyses were performed with HbA1c as the dependent variable, and risk factors correlated with HbA1c significantly and variable for each community as independent variables. To assess whether community differences affect associations between HbA1c levels and risk factors, we added interaction terms as independent variables in the logistic regression analysis.

Results: 1. There were no significant interaction terms while significant positive associations were observed between HbA1c and age, BMI, and levels of TC and gamma GTP for men in both communities. A significant negative association was observed between HbA1c and UA.. 2. Age, BMI, and the levels of SBP, TG, GPT, and gamma GTP were positively associated, and GOT was negatively associated with the HbA1c levels in women in both communities. Each community had its own association between TC and HbA1c.

Conclusions: The findings that TC is associated with HbA1c in men, and that BMI and the level of TC are linked with HbA1c in women are consistent with previous results for Japanese. The association between HbA1c and TG in women was newly observed for Japanese. Furthermore, the levels of gamma GTP in both sexes and also GPT in women are associated with HbA1c. From these results, investigating linkage between HbA1c level and atherosclerotic risk factors was thought to be appropriate for estimating accumulation of multiple risk factors in the community.