Ultrasonographic measurements of the skin, fat and muscle in vitamin D deficiency.

Abstract

Vitamin D is a steroid hormone and it is essential for the musculoskeletal system health. The relationship among vitamin D levels and adiposity was shown. However, there is only one study seems to have examined the relationship between skinfold thickness and vitamin D levels. A total of 116 healthy subjects who had a recent vitamin D measurement were included. Skin, subcutaneous fat and muscle thicknesses were measured by ultrasound (US). Hand grip strength and usual gait speed were evaluated. Subjects were classified into two groups according to 25-OH vitamin D levels. Skin thicknesses of anterior forearm in women and of anterior tibia in men, and trochanteric fat thicknesses of both genders were higher in lower 25-OH vitamin D group (both P<.05). There were no differences between the groups regarding muscle thicknesses, grip strength and gait speed (all P>.05). For identifying vitamin D deficiency (≤20ng/mL); optimal skin thickness value was 1.25mm in women (sensitivity: 91.3%, specificity: 54.7%), and optimal trochanteric fat thickness was 1.79cm in men (sensitivity: 87.5%, specificity: 76.9). The specificity was increased to 79.2% if the cut-off value was taken as 1.35mm for anterior forearm skin thickness in women. We imply that skin thicknesses (anterior forearm and tibia) and subcutaneous fat (trochanteric region) increase in subjects with low vitamin D levels. Having also ascertained the relevant cut-off values, we underscore the possible role of these measurements as regards the assessment of vitamin D status.