Background: Obesity is a rapidly growing health problem in most developed countries. Excess body weight is a risk factor for many somatic and even psychological disorders, including cardiovascular disease, type 2 diabetes mellitus, osteoarthritis and several cancer types. Recently, overweight and obesity have been shown to be related to low vitamin D status.
Materials and methods: The 25(OH)D3 status was analyzed in a population of 2,126 patients registered in a Metabolic and Medical Lifestyle Management Clinic in Oslo, Norway. Seasonal variation and prevalence of vitamin D deficiency were assessed in different body mass index (BMI), sex and age categories.
Results: For both sexes and both age groups (<50 years and > or = 50 years) there was a significant decrease of serum 25(OH)D3 levels with increasing BMI. Surprisingly, not only were the 25(OH)D3 levels negatively correlated with BMI, but the serum 1,25(OH)2D3 levels were also. The seasonal variation of serum 25(OH)D3 was highest in young (<50 years) non-obese men. The prevalence of vitamin D deficiency was highest in individuals with BMI > or = 40, being as high as 32% among women and 46% among men.
Conclusion: The 25(OH)D3 level, as well as its seasonal variation and the prevalence of vitamin D deficiency, are all dependent on BMI, and age separately. The results of the study suggest that 1 in 3 women and 1 in 2 men with BMI > or = 40 are vitamin D deficient.