Serum Total Adiponectin Level Is Associated with Incident Prediabetes in Japanese Workers

Emerging evidence suggests that adiponectin secreted into the serum by adipocytes may be involved in the development of type 2 diabetes. In addition, some cross-sectional studies have suggested that adiponectin may be related to PreD (prediabetes). Thus, it is reasonable to expect that adiponectin may play a role in PreD development. However, there are still few prospective cohort studies, which could successfully demonstrate a causative relationship between adiponectin and PreD. The aim of this study was to establish the significance of Adipo (serum total adiponectin level) as a biomarker for PreD in Japanese workers. To this end, we analyzed data in our prospective occupational-based cohort study, which has been conducted since 2008. A total of 551 workers without PreD aged 20-60 years were followed-up (mean follow-up period 4.2 years). The subjects were divided into four categories based on the quartiles of baseline Adipo for each sex (male: < 4.9, 4.9-6.6, 6.7-8.9 and > 8.9 µg/ml, female: < 8.2, 8.2-11.1, 11.2-13.9 and > 13.9 µg/ml). The age- and sex-adjusted incidence of PreD significantly increased with decreasing quartile of Adipo at baseline (P for trend <0.001). In multivariate analyses after adjusting for age, sex, BMI, smoking habit, alcohol intake, regular exercise, HDL cholesterol, triglycerides, family history of diabetes, and hypertension, the hazard ratio of PreD was 1.64 [95% confidence interval: 1.to 2.51, P=0.02] in the second quartile and 1.33 [95% confidence interval: 0.83 to 2.11, P=0.24] in the lowest quartile, when compared with the highest quartile. Furthermore, the risk of PreD was 5% higher (P=0.04) with a per 1 µg/ml decrement of Adipo in the multivariate-adjusted model. These results suggest that decreased Adipo is a risk factor for the incidence of PreD in Japanese workers, which could assign a new role to Adipo as a biomarker for the early stage of glucose homeostasis disorders, besides being a biomarker for the development of diabetes and cardiovascular events.