Effect of oral hypoglycaemic agents on bone metabolism in patients with type 2 diabetes mellitus & occurrence of osteoporosis.

Background & objectives: Type 2 diabetes mellitus (T2DM) is considered to be a protective factor against development of osteoporosis. But oral hypoglycaemic agents (OHA) are likely to increase the risk of osteoporosis. This study was carried out to evaluate the effect of various OHA on bone mineral density (BMD) in patients with T2DM. Methods: Forty one patients (study group) with T2DM (mean age 51.9±5.5 yr; 31 females) receiving treatment with oral hypoglycaemic agents (OHA) [thiazolidinediones alone (n=14) or in combination with other OHA (n=27)] for a period of at least three consecutive years and 41 age- and gender-matched healthy controls (mean age 51.4±5.1 yr) were included in the study. A detailed clinical history was taken and all were subjected to physical examination and recording of anthropometric data. BMD was assessed for both patients and controls. Results: The mean body mass index (kg/m2) (26.5±4.90 vs 27.3 ±5.33) and median [inter-quartile range (IQR)] duration of menopause (yr) among women [6(2-12) vs 6(1-13)] were comparable between both groups. The bone mineral density (BMD; g/cm2) at the level of neck of femur (NOF) (0.761±0.112 vs 0.762±0.110), lumbar spine antero-posterior view (LSAP) (0.849±0.127 vs 0.854±0.135); median Z-score NOF {0.100[(-0.850)-(0.550)] vs -0.200[(-0.800)-(0.600)]}, LSAP {-1.200[(-1.700)-(-0.200)] vs -1.300 [(-1.85)-(-0.400)]} were also similar in study and control groups. Presence of normal BMD (9/41 vs 8/41), osteopenia (16/41 vs 18/41) and osteoporosis (16/41 vs 15/41) were comparable between the study and control groups. No significant difference was observed in the BMD, T-scores and Z-scores at NOF and LSAP among T2DM patients treated with thiazolidinediones; those treated with other OHA and controls. Interpretation & conclusions: The present findings show that the use of OHA for a period of three years or more does not significantly affect the BMD in patients with T2DM.