Serum 25-hydroxyvitamin D status, quantitative ultrasound parameters, and their determinants in Greek population

Vitamin D deficiency and quantitative ultrasound measurements are associated with bone fragility. We assessed these parameters and their correlates. 87.7% of the population has vitamin D inadequacy and this correlated with lifestyle factors. These results contribute to epidemiological data needed for population guidelines for bone health.

Vitamin D deficiency and quantitative ultrasound (QUS) parameters are among the most important clinical risk factors of bone fragility. Few data are available for Greek population. The aim of the study was to evaluate the serum 25-hydroxyvitamin D [25(OH)D] level and their determinants, as well as QUS parameters in Greek population.

OSTEOS is an observational cross-sectional study conducted from June 2010 to July 2012. Nine hundred seventy adults were recruited from rural and urban areas throughout Greece and completed the appropriate questionnaire. Serum 25(OH)D measured by enzyme immunoassay, QUS parameters, broadband ultrasound attenuation (BUA), speed of sound (SOS) and stiffness index (SI), was assessed with an Achilles device. Univariate Analysis of Variance was used for the assessment of serum 25(OH)D determinants.

Mean serum 25(OH)D of the total population was 20,00 ± 8,00 ng/mL. Females had lower levels than males. The negative determinants of serum 25(OH)D in the total population were the female sex and the winter-spring season of sampling while age proved negative association solely in obese subjects. Positive determinants of vitamin D status were summer sun exposure and organized physical activity as expected. Urban had lower SOS and SI than rural residents. Individuals with 25(OH)D ≥ 20 ng/mL had higher SOS than those with 25(OH)D < 20 ng/mL. BUA, SOS, and SI are positively correlated with organized physical activity and negatively with PTH.

This study reports that vitamin D deficiency is highly prevalent among healthy Greek men and women, demonstrates the multifactorial causation of 25(OH)D levels, and points out that further research is required to determine more factors related to vitamin D status and bone health.