Risk factors of low vitamin D status in adolescent females in Kuwait: implications for high peak bone mass attainment.

UNLABELLED: Risks of low vitamin D status in Kuwaiti adolescent girls are high parathyroid hormone (PTH), high waist/hip ratio, veiling and not having a private room. Low vitamin D status is likely to have a negative impact on their bone mass and accrual.

INTRODUCTION: Low serum 25-hydroxyvitamin D (25OHD) levels are repeatedly found in females in the Middle East, which is a cause for concern particularly for adolescent females. This is because vitamin D has been shown to promote bone mineral accrual in adolescence.

PURPOSE: The aim of this study was to assess the risk factors of low vitamin D status in adolescent females and to assess its impact on their bone mass.

METHODS: Serum 25OHD and PTH were measured in 232 females. Anthropometric measurements and skin colour were obtained. Bone measurements at the lumbar spine were performed using dual-energy x-ray absorptiometry (DXA). Data on food intake, physical activity (PA) and sun exposure were taken. Binary logistic regression was used to assess the risk factors of serum 25OHD levels <25 nmol/L and multiple linear regression was used to assess the predictors of bone mineral variables.

RESULTS: Median 25OHD was 19.4 nmol/L (IQR 16.4-23.68), among which 98.7 % obtained <50 nmol/L. PTH >7 pmol/L (odds ratio (OR) 4.3; 95 % CI 1.8, 10.2), not having a private room (OR 3.7; 95 % CI 1.4, 9.8), veiling (OR 2.4; 95 % CI 1.1, 5.5) and waist/hip ratio >0.75 (OR 2.1; 95 % CI 1.0, 4.3) were risk factors of low vitamin D status, whereas, height, weight, month since menarche, PTH, animal protein intake and PA were independent predictors of bone mineral content (p < 0.05).

CONCLUSION: Low vitamin D status is prevalent in Kuwaiti adolescent females, which may have a negative impact on their bone mineralization and accrual. Further investigation is needed to reveal the underlying causes.