Vitamin D status among postmenopausal osteoporotic women: a hospital based cross-sectional study from Northern Sri Lanka

BACKGROUND: Vitamin D deficiency is common among post-menopausal women and it is important to treat vitamin D deficiency to prevent falls and fractures in patients with osteoporosis. Few studies examined the prevalence of vitamin D deficiency in general population of Sri Lanka but no studies to date done among post-menopausal women with osteoporosis in Sri Lanka. This is the first study in Sri Lanka of such kind conducted to evaluate the serum vitamin D levels among postmenopausal women. METHODS: Cross-sectional study was conducted at the Endocrine Unit, Teaching Hospital Jaffna from January to December 2018. During this period 105 postmenopausal women who registered for bone density assessment were recruited to the study. Data collection was done by investigators and blood sample was taken from each participant by registered nurses and total 25-Hydroxy Vitamin D level (25(OH)-Vit D) was measured by competitive immunoassay with enhanced chemiluminiscence technique, levels were categorized and analysis was done using SPSS 26. RESULTS: Mean age of 105 postmenopausal women was 67.7 with minimum 33 and maximum 84 years. Mean total 25(OH)-Vit D was 27.5 (range11.7–52.5 ng/mL). 25(OH)-Vit D levels were adequate in only 36.2% (95%CI: 27–45), 44% had insufficient levels and deficiency was present in 19% (95%CI: 12–27) of postmenopausal women. Among total study participants 20% were vegetarian, 53, 76.2 and 64.8% were consuming milk, fish and egg respectively and 71.4% reported adequate level of sun exposure (> 30 min/day). Commonly reported vitamin D deficiency symptoms include paraesthesia (57.1%), bone-pain (55.2%), easy fatigability (54.3%), malaise (51.4%), muscle cramps (43.8%) and proximal myopathy (40.0%). Nevertheless, comparison of musculoskeletal symptoms between group with sufficient level and group with insufficient and deficient level showed no significant difference (P > 0.05). Among 71 participants (66.7%) who completed bone density assessment, 38% (95%CI: 27–49) showed osteoporosis. Vertebral Z score showed a significant correlation with 25(OH)-Vit D level (r-0.252, P-0.03). CONCLUSION: Prevalence of vitamin D deficiency is relatively high among the post-menopausal women with a provisional diagnosis of osteoporosis. It is essential to consider vitamin D supplementation when initiating treatment for osteoporosis. Hence, Vitamin D testing is desirable in decision making to treat or not to treat.