RISK-FACTORS FOR DECREASED BONE-DENSITY IN PREMENOPAUSAL WOMEN

Osteoporosis is a major health problem. Little is known about the risk factors in premenopause. Sixty 40-50-year old patients with regular m enses were studied cross-sectionally. None of the patients were on dru gs known to interfere with bone mass. Patients answered a dietary inqu iry and had their bone mineral density (BMD) measured. The Z scores we re used for the comparisons. A blood sample was taken for the determin ation of FSH, SHBG, estradiol, testosterone, calcium and alkaline phos phatase. Calcium and creatinine were measured in 24-h urine. A Z score less than -1 was observed for the lumbar spine of 14 patients (23.3%) , and for the femur of 24 patients (40%). Patients with aZ score less than -1 for the lumbar spine were older than patients with a Z score g reater than or equal to-1 (45.7 vs 43.8 years) and presented higher va lues of alkaline phosphatase (71.1 +/- 18.2 vs 57.1 +/- 14.3 IU/l). Mu ltiple regression analysis showed that a lower lumbar spine BMD was as sociated with higher values of alkaline phosphatase, lower calcium ing estion, a smaller body mass index (BMI), less frequent exercising, and older age. The patients with a Z score less than -1 for the femur wer e shorter than patients with a Z score greater than or equal to-1 (158 .2 vs 161.3 cm). Multiple regression analysis showed that a lower femo ral BMD was associated with lower BMI, higher alkaline phosphatase and caffeine intake, and less frequent exercising. A lower than expected BMD was observed in a significant proportion of premenopausal women an d was associated with lower calcium intake, relatively lower physical activity and lower BMI. We conclude that the classical risk factors fo r osteoporosis may be present before ovarian failure, and their effect may be partly independent of estrogen levels.