To investigate the vitamin D status during winter of a healthy population of hospital employees and to assess the correlation between vitamin D status and risk of infections in the upper respiratory tract.

One hundred and ten healthy volunteers answered a questionnaire on their solar exposure habits and vitamin D intake and delivered one blood sample for quantification of vitamin D level (serum 25-hydroxyvitamin D (25(OH)D) concentration) during December 2007–January 2008. At the end of the winter we screened for the occurrence of respiratory infections and sought associations with vitamin D status.

Bucharest, Romania, 45°N.

One hundred and ten healthy hospital employees.

Eighty per cent of participants were vitamin D deficient (25(OH)D level below 50 nmol/l). The main determinant of serum 25(OH)D was sun exposure during the summer previous to the study (P = 0·02 in multivariate analysis). Intake of vitamin D, BMI and age played no significant role for the level of 25(OH)D. Overall we found a non-significant negative correlation between 25(OH)D level and new cases of infection (Spearman correlation coefficient of −0·12, P = 0·2).

Vitamin D status is alarmingly poor in active, relatively young women residing in Romania. If our results are reproduced by other investigations, action to improve vitamin D status at the population level is necessary. We were not able to show a statistically significant relationship between vitamin D status and infection risk in our material.