Objective: To explore the association between sleep disorder and osteoporosis in elderly female patients with type 2 diabetes mellitus (T2DM).
Methods: A total of 536 elderly female T2DM patients from July 2011 to July 2014 were divided into two groups of patients without sleep disorder and those with sleep disorder based upon the Pittsburgh Sleep Quality Index. The bone mineral density of femoral neck, Wards triangle, greater trochanter and lumbar spines (L2-L4) were measured by dual-energy X-ray absorptiometry. Biochemical indicators were detected in two groups. Oral glucose tolerance and insulin releasing tests were performed. We compared the differences of bone mineral density and β-cell function after fasting and glucose-load. The logistic regression analyses were performed between sleep disorder and osteoporosis and other indicators.
Results: The levels of high sensitivity C-reactive protein (hs-CRP), HbA1c, cortisol (COR), adrenocorticotropic hormone (ACTH), fasting insulin (FINS) and homeostasis model assessment-estimated insulin resistance (HOMA-IR) were significantly higher in patients with sleep disorder compared to those without sleep disorder [(3.5 ± 1.1) vs (2.6 ± 0.9) mg/L, (8.0 ± 1.9)% vs (7.3 ± 1.6)%, (512 ± 88) vs (436 ± 76) nmol/L, (6.4 ± 2.3) vs (5.1 ± 2.0) pmol/L, (13.4 ± 4.3) vs (12.4 ± 4.0) mU/L, 4.7 ± 0.8 vs 3.8 ± 0.8, all P < 0.05]. Insulin sensitivity index (ISI) was lower in patients with sleep disorder than that in patients without sleep disorder (-4.2 ± 0.5 vs -4.0 ± 0.4, P < 0.05). The bone mineral density of femoral neck, Wards triangle, greater trochanter and lumbar spines (L2-L4) were significantly lower and the prevalence rate of osteoporosis was significantly higher in patients with sleep disorder compared to those in patients without sleep disorder (all P < 0.05). Logistic regression analysis showed that sleep disorder was positively correlated with HOMA-IR, HbA1c, COR and ACTH (all P < 0.05) and negatively with ISI (P < 0.05). Logistic regression analysis showed that osteoporosis was positively correlated with postmenopausal duration, HbA1c, COR, ACTH and sleep disorder (all P < 0.05) and negatively with ISI (P < 0.05).
Conclusion: Sleep disorder causes osteoporosis through various mechanisms in elderly female T2DM patients. Improving sleep disorder may help to reduce the prevalence of osteoporosis.