Comparison of serum 25-Hydroxyvitamin D levels in women of childbearing age, oral contraceptive users, postmenopausal and who take hormone replacement therapy

ABSTRACT

There is a growing awareness that vitamin D sufficiency is required for optimal health, and also the role of vitamin D in calcium absorption and metabolism for bone health is well known. The objective of this study was to investigate the serum vitamin D level in childbearing age and postmenopausal women and comparing with women who use oral contraceptive pills [OCP] and who take hormone replacement therapy [HRT]. Ninety-seven healthy non pregnant-non lactating women with a mean age of 32.67 +/- 5.14 years old [50 OCP users and 47 non- OCP users] and 56 healthy postmenopausal women, with a mean age of 51.42 +/- 3.22 years old [29 were taking HRT and 27 were not taking HRT] were studied using biochemical procedures [measurement of serum 25-hydroxyvitamin D], anthropometric measurements [weight and height] and completing 24-hour recall questionnaire for determining daily dietary calcium intake. No significant differences were found between either OCP and non- OCP users or HRT and non- HRT groups in terms of mean body mass index [BMI], and dietary intakes of calcium. Mean daily calcium intake in all groups was lower than recommended daily allowances. There was no significant difference in serum 25- hydroxyvitamin D levels between OCP- users and non-OCP users, However the mean serum 25- hydroxyvitamin D level in HRT group was significantly higher than that of non- HRT group [P<0.01].The majority of subjects in OCP and non - OCP, and HRT groups had serum vitamin D levels lower than normal limit. Vitamin D deficiency was common in the study subjects, which may have important health consequences. Using low- dose OCP had not resulted in altered Vitamin D metabolism compared to non -OCP users. However, in postmenopausal women, taking HRT had positive effect on serum vitamin D level. It is suggested to emphasize for overcoming vitamin D deficiency in community as one of the health priorities