Bone mineral density, vitamin D status, and calcium intake in healthy female university students from different socioeconomic groups in Turkey.

Abstract

Our aims were to (1) examine the effects of different SES on BMD, vitamin D status, and daily calcium intake and (2) investigate any association between vitamin D status and BMD in female university students. A questionnaire was used to obtain information about SES, daily calcium intake, and physical activity in 138 healthy, female university students (age range 18-22years). Subjects were stratified into lower, middle, and higher SES according to the educational and occupational levels of their parents. All serum samples were collected in spring for 25-hydroxyvitamin D concentration (25OHD). Lumbar spine and total body BMD was obtained by dual-energy X-ray absorptiometry (DXA) scan (Lunar DPX series). Osteopenia was defined as a BMD between - 1.0 and - 2.5 standard deviations (SDs) below the mean for healthy young adults on lumbar spine DXA. No significant difference was found between the three socioeconomic groups in terms of serum 25OHD concentration, BMD levels, or BMD Z scores (p > 0.05). Both the daily intake of calcium was significantly lower (p = 0.02), and the frequency of osteopenia was significantly higher in girls with low SES (p = 0.02). There was no correlation between serum 25OHD concentration and calcium intake and BMD values and BMD Z scores (p > 0.05). The most important factor affecting BMD was weight (β = 0.38, p < 0.001). Low SES may be associated with sub-optimal bone health and predispose to osteopenia in later life, even in female university students.