[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 χ2 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/m², 50% were osteoporotic (p < 0.001). The risk for osteoporosis detection increased with age (OR = 1.1; CI 95% = 1.0-1.1), time of menopause (OR = 1.1; CI 95% = 1.0-1.1), smoking (OR = 1.9; CI 95% = 1.2-3.2), RA (OR = 3.6; CI 95% = 1.3-9.6) and maternal fracture history (OR = 2.1; CI 95% = 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.