Prevention of bone loss with vitamin D3 supplementation, hormone replacement therapy and combination therapy in postmenopausal women

ABSTRACT

BACKGROUND: The positive effects of hormone replacement therapy (HRT) on the skeleton in postmenopausal women are well defined. However, the effects of vitamin D supplementation on BMD in postmenopausal women are controversial. But many women, who are contraindicated to HRT or afraid of side effects of HRT or are already on HRT regimen, take calcium plus vitamin D supplement for prevention of osteoporosis. Therefore, this study was designed to examine the effect of vitamin D supplementation on BMD in postmenopausal women and to determine whether vitamin D supplementation can give additional benefit to HRT. METHODS: Subjects were 109 postmenopausal women out of total 213, who visited the Sacred Heart Hostpital, Chuncheon and had follow up BMD study one year after druing January, 1996 to May, 1999. The study group was as follows No treatment (n=31) ; Vit D (n=11) ; HRT (n=50) ; HRT+Vit D (n=17). We compared and analyzed the changes of BMD in the region of lumbar spine (L2-4) and femur (femoral neck, trochanter, Ward's triangle). SPSSWIN 7.5 was used for statistical procedure. RESULTS: Subject had a mean age of 54.4+/-5.7 years, mean menopausal age of 48.4+/-2.4 years, mean postmenopausal duration of 6.1+/-4.1 years, and mean body mass index of 24.1+/-2.8 kg/m2. No correlation was observed between general characteristics (age, menopausal age, postmenopausal duration, and body mass index) and changing rate of BMD. Lumbar BMD had increased by 1.83% in the Vit D group, by 1.95% in the HRT group and by 3.15% in the HRT+Vit D group, whereas it had decreased by 1.99% in the no treatment group. The increase of femoral neck BMD in the Vit D group was 1.5%, in the HRT group 0.66% and in the HRT+Vit D group 2.09%, but the loss in the no treatment group was 1.65%. The changes of trochanteric BMD were as follows No treatment group (-2.49%), Vit D group (0.04%), HRT group (1.48%), and HRT+Vit D group (1.81%). In Ward's triangle BMD the changes were as follows No treatment group (-4.09%), Vit D group (1.17%), HRT group (-0.01%), HRT+Vit D group (0.16%). In the Vit D group, except for the trochanteric area (P>0.05), there was a significant increase in BMD of L2-4, femoral neck, and Ward's triangle (P<0.05), whereas in the HRT group and HRT+Vit D group significant increases were observed in all areas (P<0.05). But there was no significance among Vit D group, HRT group and HRT+Vit D group. CONCLUSION: This study confirmed the beneficial effect of HRT on lumbar and femoral BMD. It also showed that low dose Vitamin D supplementation had effect in the prevention of osteoporosis in postmenopausal women. In the HRT+Vit D group, BMD had increased more than HRT alone, but does not give any benefit additional to that of HRT alone.