Risk of bone loss in men with multiple sclerosis.

CONTEXT: Osteoporosis and the increased fracture risk associated with osteoporosis become apparent in men approximately 10 years later than women. However, in recent studies, approximately 20% of healthy men in the age range 55-64 years were found to be osteopenic. Emerging data suggest a significantly increased prevalence of osteoporosis in men and women with multiple sclerosis (MS) compared to age-matched controls, but no specific clinical testing recommendations are available for men.

OBJECTIVE

To determine the proportion of male MS patients with osteoporosis and to identify the factors associated with the reduction in bone mass.

DESIGN

Consecutive male MS patients seen at our MS clinic were screened with dual-X-ray absorptiometry (DEXA) scan for determining the bone mineral density (BMD). All patients had neurological Expanded Disability Status Scale (EDSS) evaluation. The results were compared to healthy age-matched male reference population using the Z score and to a cohort of women MS patients and women controls. Calcium, total testosterone, sex-hormone binding globulin (SHBG), 25-hydroxy-vitamin-D, and parathyroid hormone (PTH) were evaluated in male patients with decreased BMD. Relevant data on body mass index (BMI), medication, alcohol consumption, smoking, and sexual dysfunction were recorded.

SETTING

Academic MS Centre.

PATIENTS AND OTHER

PARTICIPANTS

Forty consecutive male MS patients, age mean 51.2 +/- 8.7 years, and mean EDSS of 5.8 +/- 1.9 were evaluated with DEXA scan. Of these, 17.5% patients were relapsing-remitting (RR) MS, 57.5% were secondary progressive (SP) MS and 25% were primary progressive (PP) MS.

MAIN OUTCOME MEASURE: Proportion of male MS patients with reduced BMD at the lumbar spine and femoral neck.

RESULTS

Thirty-two (80%) of our patients had a reduced bone mass of either lumbar spine or the femoral neck; of these 17 patients (42.5%) had osteopenia and 15 patients (37.5%) had osteoporosis. Twenty-one per cent (eight out of 38 patients) had vertebral, rib or extremities fractures. Multivariate linear regression analysis indicated that the EDSS (P < 0.0001) and BMI (P = 0.0004) were the important factors associated with low BMD at the femoral neck and the EDSS was the important factor (P = 0.0017) associated with low BMD at the lumbar spine. The same factors emerged as significantly associated with the corresponding Z scores, which are corrected for age and sex. No clear association between intravenous steroid therapy and BMD was evident in the multivariate analysis. Low levels of 25-hydroxy-vitamin-D were seen in 37.5% of patients.

CONCLUSIONS

The proportion of male MS patients with reduced bone mass is high and disproportionate to their age and ambulation, consistent with an association between the MS disease process and pathological bone loss. Increased awareness and bone density screening of male and female MS patients over 40 years of age is warranted.