VITAMIN D STATUS IN RELATION TO DIETARY INTAKE, SUN EXPOSURE OBESITY, LIFESTYLE FACTORS AND BONE HEALTH AMONG SAUDI PREMENPOUSAL WOMEN LIVING IN JEDDAH CITY

Abstract

Saudi women are at risk of vitamin D deficiency and low bone mass because traditional clothing and time spent indoors limit sun exposure. However, no information about other contributing individual, demographic, and cultural risk factors which may determine women’s vitamin D status is available. Moreover, little is known about vitamin D intake, and the association between vitamin D and calcium intake and bone mineral density (BMD) in premenopausal Saudi women. The objectives of the study were to identify predictors strongly associated with vitamin D deficiency, identify dietary vitamin D sources, examine potential determinants of vitamin D intake, examine the association of vitamin D and calcium intake with BMD, and explore how the relationship between knowledge of vitamin D and attitudes about sun exposure are related to serum vitamin D levels.

This cross-sectional study was conducted in 257 women 20–50 years of age in Jeddah, Saudi Arabia, between December 2014 and April 2015. Data were obtained through pre-tested questionnaires. Serum 25(OH) D and serum parathyroid hormone (PTH) were measured. BMD was measured using double-energy X-ray absorptiometry in 102 participants. The prevalence of vitamin D deficiency was 77.6% (25(OH) D < 50 nmol/L). Vitamin D deficiency is associated with increased risk of elevated PTH levels. In the multiple regression analysis, serum 25(OH) D was not associated with body mass index or waist circumference. Predictors of vitamin D deficiency were low dietary and supplement vitamin D intake and younger age, explaining 41% of the variation in 25(OH) D serum concentrations (p < 0.001). Approximately 65% of the participants had vitamin D intakes below the U.S. Estimated Average Requirement (EAR) for vitamin D, and 61% fell below the EAR for calcium. Dairy products and supplements contributed the most to vitamin D intake. Older age was an independent determinant of sufficient vitamin D intake (p < 0.001). The prevalence of osteopenia was 33% in the lumbar spine and 30% in the femur neck. Education was a significant predictor of vitamin D knowledge (p < 0.001). Public health interventions offering early screenings of vitamin D status and improved nutrition in young Saudi women are recommended.