The Prevalence of Vitamin D Deficiency and Associated Factors Among Subfertile Women: An Initial Experience From Northern Sri Lanka.

Subfertility is a global burden. Low vitamin D status has been associated with an increased risk for subfertility. Even though the prevalence of vitamin D deficiency is very high among women in Sri Lanka, not much importance is given to addressing the issue, especially among subfertile women. Moreover, no studies have been reported on the prevalence of vitamin D in subfertile women in Sri Lanka. Thus, the current study aimed to assess the prevalence and associated risk factors among subfertile women in the northern part of Sri Lanka.  Methodology: This was a cross-sectional study comprising an interviewer-administered questionnaire and a laboratory analysis of vitamin D conducted on 371 subfertile women above 18 years of age who attended the subfertility clinic at the Professorial Unit in the Jaffna Teaching Hospital, Jaffna, Sri Lanka, between January 2023 to October 2023. Considering the time limitation and sample size, subfertile women attending during the study period were included without any sampling technique. Competitive chemiluminescence immunoassay for 25 hydroxy vitamin D (25(OH)D) was used to estimate the vitamin D level, and an external quality assessment (EQA) standard was used to categorize the level into deficient, insufficient, and sufficient. Chi-squared and ANOVA tests were used to assess the factors associated with vitamin D levels using IBM SPSS Statistics for Windows, Version 21.0 (Released 2012; IBM Corp., Armonk, New York, United States).  Results: The mean age of subfertile women was 33.7 years (SD=6.7), and nearly half of them (n=173, 46.6%) were in the age group of 30-40 years. All the participants (n=371, 100%) were Sri Lankan Tamil, the majority (n=289, 77.9%) of them were Hindus, and nearly three-quarters of the participants (n=269, 72.5%) were unemployed. Moreover, almost 90% (n=334) of the subfertile women never estimated their vitamin D level prior to the study. The study revealed that only 36.4% (n=135) of subfertile women had adequate vitamin D levels, whereas 63.4% (n=235) had inadequate and low BMI levels, and intake of fish and eggs was statistically associated with adequate vitamin D levels.  Conclusion: The study recommends a routine assessment of vitamin D levels, periodical monitoring of vitamin D levels for all subfertile women with particular attention towards the obese and overweight category, and a combination of pharmacological and dietary interventions to improve vitamin D levels, which might benefit the fertility outcome.