Circulating osteocalcin is unrelated to glucose homoeostasis in adults with type 1 diabetes

AIMS: To assess the relationship between total osteocalcin (tOC), undercarboxylated osteocalcin (ucOC) and a range of markers of glucose homeostasis in type 1 diabetes.

METHODS: One hundred and eight community-based Caucasian adults (53 males, 55 females) without a history of osteoporosis and with a mean±SD age 39.1±15.1years and median [inter-quartile range] type 1 diabetes duration of 14.3 [6.6-20.4] years participated in a cross-sectional study of bone health. Fasting serum glucose and HbA1c, and serum tOC, ucOC, total adiponectin and procollagen type 1N-terminal propeptide (P1NP) were measured using validated assays, and daily insulin dose and estimated glucose disposal rate (eGDR) were calculated. Multiple linear regression was used to determine independent associates of markers of glucose homoeostasis (HbA1c, fasting serum glucose, daily insulin dose, eGDR and serum total adiponectin).

RESULTS: In sex-adjusted multivariable regression analyses, ln(serum P1NP) was independently and inversely associated with ln(HbA1c) and ln(serum adiponectin) (P≤0.013). Other associations included those between ln(serum vitamin D) and ln(HbA1c) (inversely), daily insulin dose (inversely) and eGDR (positively) (P≤0.035), as well as an inverse relationship between overweight by waist circumference and ln(serum adiponectin) (P<0.001). Ln(serum tOC) and ln(serum ucOC) were not independently associated with any glucose homoeostasis marker.

CONCLUSIONS: These data from well characterized community-based adults with type 1 diabetes do not suggest that there is a role for osteocalcin in the potentially complex interplay between the skeleton and energy homoeostasis in type 1 diabetes.