Serum 25-hydroxyvitamin D is associated with obesity and metabolic parameters in US children

Low serum 25-hydroxyvitamin D (25(OH)D) concentration has been associated with obesity and metabolic syndrome (MetS), but few studies have addressed these associations in the USA where the prevalence of vitamin D deficiency, obesity and related metabolic disorders in children is high. [...]there is insufficient evidence to support a causal link. [...]low serum 25(OH)D concentration is likely to be a consequence rather than the cause of obesity and MetS. In obese adults, the lower serum 25(OH)D concentration could be due high sequestration of vitamin D in body fat tissues, less sunlight exposure or reduced absorption of dietary vitamin D(22,23), which may lead to less bioavailability of vitamin D(24). Activation of adipocyte pro-inflammatory pathways reduces demand for TAG storage and increases NEFA levels, which can result in increased levels of insulin resistance in adipose tissue. [...]chronic inflammation appears to reside in obese adipose tissues(25).