Risk factors for osteoporosis in postmenopausal women from southeast Brazilian

PURPOSE: To evaluate bone mineral density (BMD) and their risk factors associated with postmenopausal osteoporosis. METHODS: A cross-sectional clinical study was performed on 431 women (aged 40 - 75 years). Inclusion criteria: amenorrhea >12 months and age >= 45 years or, bilateral oophorectomy >= 40 years with BMD values (T-score of lumbar spine/femur neck) by DXA of the last 12 months. Risk factors evaluated: age, age and time of menopause, smoking, physical activity (30 min/5 times/week), rheumatoid arthritis (RA), use of corticotherapy and hormone therapy (HT), previous fracture, maternal hip fracture and body mass index (BMI=weight/height2). The chi(2) test and the logistic regression method (Odds Ratio - OR) were used to determine osteoporosis risk. RESULTS: According to WHO criteria, 106 (24.6%) women showed osteoporosis (T-score <=-2.5 DP), 188 (43.6%) osteopenia (-1.0/-2.4 DP), and 137 (31.8%) were normal (>=-1.0 DP). Osteoporosis was detected in 12% of women aged 40 - 49 years, in 21.8% of women aged 50 - 59 years and in 45.7% of women aged >60 years (p<0.001). Osteoporosis occurred in 11.8% of women with a menopause period <5 years, in 29.4% with a menopause period from 6 to 10 years, and in 41% of women with a menopause period >10 years (p<0.001). Of the women with early menopause, 80% showed osteopenia/ osteoporosis (p=0.03), and of those with BMI <20 kg/m(2), 50% were osteoporotic (p<0.001). The risk for osteoporosis detection increased with age (OR=1.1; CI95%=1.0- 1.1), time of menopause (OR=1.1; CI95%=1.0- 1.1), smoking (OR=1.9; CI95%=1.2- 3.2), RA (OR=3.6; CI95%=1.3- 9.6) and maternal fracture history (OR=2.1; CI95%=1.1- 3.0) (p< 0.05). In contrast, HT use (OR=0.3; 95% CI=0.2- 0.6) and high BMI (OR=0.9; 95% CI=0.8- 0.9) reduced the risk (p< 0.05). CONCLUSION: In postmenopausal women, age, time of menopause, smoking and maternal history of fracture were clinical indicators of risk for osteoporosis, whereas HT use and high BMI proved to be protective factors.