Abstract P060: Plasma Osteocalcin And Incident Diabetes Mellitus: The Atherosclerosis Risk In Communities (ARIC) Study

Abstract

Introduction: Diabetes is a major risk factor for cardiovascular disease. Osteocalcin is a vitamin K-dependent, bone-derived hormone that functions as an endocrine regulator of energy metabolism, male fertility, and cognition. Early studies of endocrine effects of osteocalcin have shown that genomic deletion of osteocalcin in mice resulted in a diabetic phenotype (i.e. glucose intolerance, and insulin resistance). However, results from clinical studies have shown mixed associations between blood levels of osteocalcin and risk of incident type 2 diabetes mellitus. Hypothesis: Lower values of plasma osteocalcin would be associated with an increased risk of diabetes. Methods: A total of 11,557 ARIC participants without diabetes at baseline were followed from ARIC visit 3 (1993-1995) through 2018. Diabetes cases were identified through self-report on annual and semi-annual follow-up phone calls. Plasma osteocalcin data was measured using an aptamer-based proteomic profiling platform (SomaLogic). We used Cox regression to evaluate the association of quintiles of plasma osteocalcin and incident diabetes. The primary model adjusted for age, sex, and race-center. Results: Participants were age 60 ± 5.6 years at visit 3, 56% identified as female, 21% identified as Black. There were 3,031 incident diabetes cases over a median follow-up of 17.9 years. Mean ± SD was 10.053 ± 0.775. When comparing the highest quintile of plasma osteocalcin (values 10.42 to 14.66) to the lowest quintile (values 9.03 to 9.52), there was no association with incident diabetes (HRs [95% CIs]: 0.92 [0.81, 1.02]). There was also no significant trend across the quintiles (p = 0.19). Results were similar when adjusting for additional potential confounders, and when limiting the follow-up time to 10 years. Conclusions: These data do not support the hypothesis that total plasma osteocalcin, as measured by Somalogic proteomic panel, is a biomarker associated with diabetes risk. It is possible that total plasma or serum osteocalcin and/or other isoforms of osteocalcin protein (i.e. gamma carboxylated or uncarboxylated osteocalcin) measured via other validated methodologies may be linked to diabetes.