Background: In Europe, the rate of 25(OH)D deficiency is considered high. Thus, it seems necessary to conduct population-based studies to fully assess vitamin D deficiency in various groups of patients.
Objectives: To evaluate serum 25(OH)D levels and the frequency of deficiency in women in Poland with endocrine and osteoporotic disorders. The influences of diet, use of vitamin/mineral supplementation and exposure to ultraviolet (UVB) radiation on vitamin D status in women with metabolic disorders were also examined.
Material and methods: The patient group consisted of 223 women aged 19-81 years diagnosed with endocrine and/or osteoporotic disorders. The control group consisted of 108 clinically healthy women aged 26-72 years. Serum 25(OH)D concentration was assessed using a chemiluminescent immunoassay (CLIA). An ad hoc questionnaire was used to assess the participants' exposure to UVB radiation. Food intake was assessed using a three-day 24-hour questionnaire interview.
Results: The following groups showed significantly higher 25(OH)D levels: women taking vitamin D supplements compared to women not taking vitamin D supplements (29.3 ±3.2 compared to 19.5 ±3.7 ng/mL, p = 0.0024); premenopausal women compared to postmenopausal women (28.9 ±5.2 compared to 21.5 ±4.5 ng/mL, p = 0.0021); women who visited sunny countries in the last 6 months compared to women who did not (28.1 ±3.1 ng/mL compared to 24.5 ±5.3 ng/mL, p = 0.0031); and normal weight or overweight women (according to body mass index (BMI)) compared to obese women (27.4 ±4.5 ng/mL compared to 22.3 ±4.7 ng/mL, p = 0.0431). In addition, 25(OH)D concentration correlated with total dietary vitamin D intake in the patient group (R = 0.17, p = 0.0021). Of all examined food groups, fish consumption affected serum 25(OH)D levels in patients (R = 0.20, p = 0.0421) and controls (R = 0.29, p = 0.0002). Consumption of fish products contributed to statistical differences between the patient group (R = 0.17, p = 0.0072) and healthy subjects (R = 0.19, p = 0.0032).
Conclusions: The most crucial factors influencing vitamin D status in the studied women were regular fish consumption, spending holidays in sunny destinations and regular intake of vitamin D preparations.
Keywords: 25(OH)D; diet; metabolic disorders; ultraviolet radiation; vitamin D status.