English abstract
Objectives: 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. Methods: 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. Results: 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/m2, 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. Conclusion: 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.
