Prevalence of osteoporosis and factors affecting bone mineral density in elderly women with type 2 diabetes mellitus

Abstract

Objective To investigate the prevalence of osteoporosis in elderly women with type 2 diabetes mellitus(T2DM) and associated factors. Methods From January 2011 to February 2012, 167 elderly women with T2DM and 138 healthy elderly women (controls) were enrolled in this study. The medical history, bone densitometry and biochemical indicators were recorded in the two groups. Data were analyzed with multivariate logistic regression and multiple regression analysis to identify the impacting factors of the osteoporosis in the elderly female patients with T2DM. Results There were 167 elderly women in T2DM group, aged 60-78 years; and 138 elderly women in control group, aged 60-80 years. Total incidence of osteopenia and osteoporosis in T2DM group (85.6% (143/167)) was lower than that in control group(97.1% (134/138)) (χ2=11.929, P=0.001). The risk of developing low bone mass and fracture in T2DM group was 0.178 and 1.776 times of that in control group, respectively. Set low bone mass as dependent variable, the variables of frequency of physical exercise, duration of physical exercise and body mass index(BMI) entered the logistic regression equation, and the regression coefficients B were -0.438, -0.840 and -0.297, respectively, all P<0.05. T2DM was excluded from this equation, but it entered the logistic regression equation with fracture as dependent variable. The levels of tartrate-resistant acid phosphatase 5b and urinary hydroxyproline/creatinine were higher in T2DM group than those in control group(adjusted for BMI and life style, F=3.818, 1.541, both P<0.05). While the levels of bone glaprotein and bone-specific alkaline phosphatase were lower in T2DM group than those in control participants (adjusted for BMI and life style, F= 0.407, 0.920, both P<0.05). Conclusion The risk of developing low bone mass is lower in elderly women with T2DM than the control participants, but the risk for fracture is higher, and the osteoporosis in these patients is more difficult to be identified. Key words: Diabetes mellitus, type 2; Bone density; Osteoporosis; Bone loss