Prevalence of Vitamin D Deficiency among Postmenopausal Women at Srinagarind Hospital, Khon Kaen Province, Thailand.

Abstract

Background

Vitamin D is essential for bone strength and development.  It enhances intestinal absorption of calcium and its apposition to bone.  It also increases muscle strength.  In vitamin D deficiency condition, blood calcium is depressed, parathyroid hormone production is stimulated resulting in secondary hyperparathyroidism which promotes bone turnover.  Cortical bone is the primary site affected, particularly at the femoral neck.

In previous studies, we documented an average calcidiol level of £ 35 ng/ml as  vitamin D deficiency.  A very high (> 60%) prevalence of  vitamin D deficiency was found among urban elderly women in Khon Kaen, in contrast to less than 20% among their rural counterparts.  Until now, only limited data has been available on the average level of calcidiol and prevalence of vitamin D deficiency among postmenopausal women in Thailand.

Objectives

Primary:                 Ascertain the prevalence of vitamin D deficiency among postmenopausal women

Secondary:             1. Find out the average vitamin D (calcidiol) level in postmenopausal women

2. Find out the correlation between calcidiol and PTH in the pooled data

3. Find out the calcidiol level which indicates the level of vitamin D deficiency in the pooled data

Design Cross-sectional, descriptive study

Setting Postmenopausal Clinic, Srinagarind Hospital, Khon Kaen, Thailand

Outcome measurement Serum calcidiol, PTH, and alkaline phosphatase

Results The pooled data set comprised 332 cases including 98 cases of postmenopausal women, 104 cases of previously cited urban elderly women, and 130 cases of rural elderly women. The mean (SD) calcidiol level among the postmenopausal women was 32.58 (8.93) ng/ml, and calcidiol and PTH had reverse relation with the correlation coefficient (r) = -0.265 (p-value < 0.001).  Calcidiol at £ 35 ng/ml was associated with a significant increase in PTH, which indicated the level of vitamin D deficiency. The prevalence of vitamin D deficiency in postmenopausal women was 60.2 percent.

Conclusion

The high prevalence of vitamin D deficiency with low average level of calcidiol among postmenopausal women suggests a risk for developing osteoporosis.  Outdoor exercise with sunlight exposure, high vitamin D diet intake, or, if necessary, supplementation with vitamin D is advised.

Keywords: Vitamin D Deficiency; Calcidiol; PTH; Postmenopausal Women