have a BMI >25 (p = 0.002) (data not shown). Most within-category
comparisons were not statistically significant, however 25(OH)D
concentration was significantly higher in participants who were
Australian-born (72.3 nmol/L vs 53.5 nmol/L in those born in other
countries, p < 0.001), who consumed alcohol on two or more days
in the past week (75.4 nmol/L vs 61.5 nmol/L in those who
consumed alcohol on one day or less in the past week, p = 0.007)
and who wore sunscreen (70.4 nmol/L vs 52.8 nmol/L in those who
did not wear sunscreen, p = 0.006).
3.3. Winter study
99 participants (mean age 37.8 9.1 years) completed the
winter study. As most participants (N = 69) were in both summer
and winter studies, the demographic characteristics of the groups
are similar (Table 2). The mean (SD) 25(OH)D concentration of the
winter sample was 38.9 17.1 nmol/L (range: 11.1–109). There was