Endocrine Abstracts

Background: Obesity has been associated with low levels of 25-hydroxyvitamin D (25(OH)D). This could be explained by a low dietary intake, reduced sun exposure or less biodisponibility because of its arrest in the fat mass. The main objective is to study the prevalence of 25(OH)D deficiency in premenopausal obese women.

Methods: Aleatory sample of 100 morbidly obese patients. Selection criteria were: women, premenopausal, Caucasian. Patient with diabetes mellitus (pathologic oral glucose tolerance test or previous history), renal or hepatic failure and those treated with biphosphonates, calcium or vitamin D were excluded. 35 severely obese women (mean age: 36.6±11 year, mean BMI: 49.4±6.6 kg/m²) were enrolled. Anthropometric data were measured and the body composition was estimated by bioelectrical impedance. 25(OH)D level >30 ng/ml was considered normal, < 20 ng/ml as deficiency and between 20 and 30 ng/ml as a relative deficiency. Pearson’s correlation coefficient was used to analyse the relationships between quantitative variables.

Results: Mean waist circumference was 131.5±12.8 cm. Mean percentage fat mass was 50.9±3.8%. Mean 25(OH)D level was 20.5±2 ng/ml.

Six of the studied women (17.14%) had normal 25(OH)D levels, 8 (22.86%) and 21 (60%) of them had relative deficiency and deficiency respectively.

25(OH)D levels presented a negative correlation with weight (r: −0.365; P: 0.04), BMI (r: −0.369; P: 0.038), waist circumference (r: −0.42; P: 0.021) and the fat mass percentage (r: −0.382; P: 0.031).

Conclusions:
1. The prevalence of 25(OH)D deficiency in premenopausal morbidly obese women is high (60%).

2. The negative correlation of 25(OH)D levels with BMI, waist circumference and fat percentage suggests a possible implication of excess body fat mass in the apparition of 25(OH)D deficiency.