Vitamin D status and anthropometric indices of an Omani study population

ABSTRACT

Serum 25-hydroxyvitamin D [25[OH]D] concentrations reflect vitamin D status, with deficiency implicated as causative of many diseases. This study assessed vitamin D status and anthropometric indices in a sample of healthy Omanis. Serum 25[OH]D concentrations were measured by high performance liquid chromatography in 206 healthy Omanis, aged 18-55 years [mean age men 31.1, women 26.8] in Muscat, Oman. Of this number, 95% indicated that they had never taken vitamin D supplements. Findings were compared with published values for populations domiciled in more northerly latitudes. Classical procedures were used to determine global obesity [body mass index [BMI]], and central obesity determined by waist circumference, waist-to-hip ratio [WHR], and waist-to-height ratio. Women, as compared to men, had markedly lower concentrations of 25[OH]D. Applying the cut-off point of serum 25[OH]D levels at 50 nmol/L, the prevalence of vitamin D deficiency in the study population was 87.5%; this was higher than the rates reported for the British, and European-, Hispanic-, and African-Americans. At a BMI cut-point of >/= 30 kg/m[2], the prevalence of obesity was 14.6%; this was lower than the rates reported for European-, Hispanic-, and African-Americans. Levels of 25[OH] D increased relative to age and obesity. WHR was the main predictor of 25[OH]D levels. The striking vitamin D deficiency seen in the study population, relative to more northerly populations, may be linked to sun avoidance, inadequate dietary vitamin D, and virtual non-intake of supplemental vitamin D. Age and male-gender determined the status of vitamin D and of obesity