25(OH)D serum concentration in women with menstrual disorders -risk factors for Vitamin D deficiency

Vitamin D (VD) plays a crucial role in calcium metabolism as well as immunological and endocrine homeostasis. Previous studies revealed strong inverse correlation between VD levels and insulin resistance, parathyroid dysfunctions and autoimmune thyroid disease. Insufficient evidence concerns its dependency of ovarian hormones. Malfunctioning of the ovaries results in menstrual disorders that are one of the most common endocrine impairments in young women of reproductive age.

The study was aimed to evaluate the correlation between 25(OH)D serum concentration and estradiol, testosterone as well as body mass index (BMI) in women with oligomenorrhea. 134 women of reproductive age with oligomenorrhea were eligible for the study. 25-hydroxyvitamin D [25(OH)D], estradiol, testosterone and sex hormone-binding globulin (SHBG) were measured using chemiluminescence immunoassay. Free androgen index (FAI) and body mass index (BMI) were calculated.

Critical 25(OH)D deficiency (<10 ng/ml) was found in 13.4% of women, the risk of deficiency (<30 mg/dl) was diagnosed in 69.4%, while sufficient level of VD (>30 mg/ml) in 17.2% of them. Significant negative correlation was detected between 25(OH)D and estradiol serum concentrations (r=-0.2; p=0.049), as well as BMI levels (r=-0.22; p=0.01). However, no significant correlation was found between 25(OH)D and testosterone (r=-017; p=0.055), SHBG (r=0.08; p=0.4) and FAI (r=-0.1; p=0.24).

Thorough assessment of vitamin D deficiency/insufficiency is required among patients with menstrual disorders, especially those overweighed and obese. Early screening and VD supplementation in women with estrogen-dependent disorders may become a part of routine management in order to optimize endocrine health.