Determinants of sun exposure time among Sri Lankan pregnant women.

Introduction: Sun exposure becomes extremely important for primary prevention of vitamin D deficiency (VDD) for high-risk populations who do not receive supplemental vitamin D. The present study investigated the determinants of sun exposure time and its association to vitamin D among Sri Lankan pregnant women in a primary health care population from the Colombo District.Methods: This is part of a cross-sectional study of 383 third trimester pregnant mothers from primary healthcare (PHC) units in the Colombo District in Western Sri Lanka. A newly developed interviewer-administrated questionnaire was used as the main study instrument. In addition, a venous blood sample was collected for 25(OH)D levels. The univariate and multivariate analysis examined the determinants of sun exposure time. One-way ANOVA and Tukey post hoc test described the association between sun exposure time and vitamin D level.Results: Most (56.9%) had <30 minutes of sun exposure per day. Low sun exposure time observed with Moor ethnicity (OR:7.45, 95% CI: 3.764, 14.741, p<0.001), lower parity (OR:0.53, 95%CI: 0.369, 0.753, p<0.001) and higher educational level (OR: 3.10, 95% CI: 1.606, 5.976, p=0.001). Women who spent ≥30 minutes exposed to sun between 9am to 3pm [F(3,373)=10.1, p<0.001] had higher vitamin D levels.Conclusions: Educational level, parity, and ethnicity are important determinants of sun exposure time. A significantly lower serum vitamin D is demonstrated in pregnant women with exposure time <30 minutes. This evidence will allow health personnel to individualize the advice to improve vitamin D-related sun exposure behaviour in this population who are not routinely supplemented with vitamin D.