Vitamin D deficiency in early autumn among predominantly non-elderly, urban adults in Northern Poland (54°N).

INTRODUCTION

Data on vitamin D status among non-elderly adults from Central Europe are insufficient. Natural sunlight allows for cutaneous vitamin D synthesis only from April through August at latitudes over 54° in the northern hemisphere. In this study we aimed at determining vitamin D status among adults in the first weeks of autumn in northern Poland.

MATERIAL AND METHODS

A convenience sample of community-dwelling, predominantly urban and non-elderly adults was recruited in an outpatient clinic. Questionnaire and laboratory examinations were performed from September 26 through November 8. The latter comprised serum alkaline phosphatase activity (ALP), 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH), calcium, and phosphorus concentrations.

RESULTS

180 women and 124 men were enrolled into the study, aged 46+/-14.1 years (mean+/-standard deviation, SD). Mean 25-hydroxyvitamin D concentration of the studied sample was 21.1+/-9.3 ng/ml. More than 50% of studied subjects were vitamin D deficient (i.e. had 25(OH)D concentrations of less than 20 ng/ml), only 15.1% reached vitamin D concentrations of ≥30 ng/ml (sufficiency). Median 25(OH)D concentrations were higher in participants who declared longer sun exposure as well as those who supplemented vitamin D. A negative correlation was found between PTH and 25(OH)D concentrations: r=-0.23, p<0.001 (Spearman rank order test).

DISCUSSION

While there are a number of methodological limitations concerning the current study, the acquired results broaden the scarce amount of data on vitamin D status in Central Europe. Our data correspond well with those from previous studies. The presented study should be considered precursory to further research.