Data are presented as median (interquartile range) or n (%), unless otherwise indicated. Vitamin D deficient is Serum 25(OH)D₃ <30 nmol·L⁻¹, while not deficient is ≥30 nmol·L⁻¹. Where proportions are shown, they were calculated using the n numbers shown in columns as denominator; p-values were calculated using Mann–Whitney test for data presented as median and interquartile range, and by Fisher's exact test for data presented as n (%), with p<0.05 considered significant. The sample size for the backward logistic regression is 379, with 13 excluded from this analysis; seven because gender was not stated, five due to ethnicity not stated and one with body mass index (BMI) unknown. Age and BMI were treated as continuous variables, job role as nine categories, while all others were treated as dichotomous. Eight participants were taking vitamin D supplements, one in the vitamin D deficient group and seven in the non-vitamin D deficient group. Comorbidities were classified as shown because they were uncommon in this cohort, with the most common comorbidities being hypertension (n=34, 9%) and asthma (n=26, 7%). ^#: p-value of 0.226 when excluding junior doctor group in analysis. BAME: Black, Asian and minority ethnic demographic group.