Abstract
Vitamin D status varies with age, sex, body mass index (BMI), race, skin color, latitudes, sun exposure, and dietary intake [1]. A level between 52 and 72 nmol/l (21-29 ng/ml) has been defined as a state of insufficiency and a level of <50 nmol/l (<20 ng/ml) as vitamin D deficiency [2]. Vitamin D deficiency has been found to be common among the healthy Saudi population [3,4]. Homozygous sickle cell disease (SCD-SS) is also common in Saudi Arabia, affecting up to 5.27% of the population [5]. Young Saudi patients with homozygous sickle cell disease were found to have high prevalence of low bone mass [6,7]. We hypothesize that low 25(OH) D could be one of the influencing factors among Saudi patients with homozygous SCD for decreased bone density.