To investigate the association between sleep disorders and osteoporosis in elderly male patients with type 2 diabetes.

Four hundred and twenty-eight elderly male patients with type 2 diabetes mellitus treated from July 2011 to July 2014 were divided into two groups according to Pittsburgh Sleep Quality Index: patients without sleep disorders and patients with sleep disorders. The bone mineral density of the femoral neck, Ward triangle, greater trochanter and lumbar spine (L2-L4) was measured by dual-energy X-ray absorptiometry. Biochemical indicators were detected in the two groups. Oral glucose tolerance test, insulin releasing test and glucagon releasing test were performed. We compared differences in bone mineral density and α-cell and β-cell function after fasting and glucose-loading between the two groups. The correlation between sleep disorders and other indicators was analyzed and regression analysis was performed.

The bone mineral density of the femoral neck, Ward triangle, greater trochanter and lumbar spine (L2-L4) was lower and the prevalence of osteoporosis was higher in patients with sleep disorders than in patients without sleep disorders (all P<0.05). Glycosylated hemoglobin A1c (HbA1c), fructose amine, fasting insulin, and homeostasis model assessment of insulin resistance index (HOMA-IR) were higher in patients with sleep disorders than in patients without sleep disorders 〔(8.1±1.9)% vs. (7.5±1.7)%, (0.32±0.11) mmol/L vs. (0.30±0.09) mmol/L, (13.29±4.48) mU/L vs. (12.26±4.38) mU/L, (4.58±0.81) vs. (3.72±0.76), respectively, all P<0.05〕. The insulin sensitivity index was lower in patients with sleep disorders than in patients without sleep disorders 〔(-4.26±0.52) vs. (-4.06±0.48), P<0.05〕. The level of glucagon at each time point and the area under the curve of glucagon were higher in patients with sleep disorders than in patients without sleep disorders. The glucagon/insulin ratio and glucagon/glucose ratio at 0, 30, 60, and 180 min were higher in patients with sleep disorders than in patients without sleep disorders (all P<0.05). Logistic regression analysis showed that sleep disorders were positively correlated to HOMA-IR, glucagon/insulin ratio and osteoporosis, and negatively correlated to insulin sensitivity index (all P<0.05).

Sleep disorders may cause osteoporosis through various mechanisms. Improvement in sleep may help to reduce the incidence of osteoporosis.

Diabetes mellitus, type 2; Sleep disorder; Osteoporosis