PT - JOURNAL ARTICLE AU - Lugg, Sebastian T AU - Mackay, William R AU - Faniyi, Aduragbemi A AU - Faustini, Sian E AU - Webster, Craig AU - Duffy, Joanne E AU - Hewison, Martin AU - Shields, Adrian M AU - Parekh, Dhruv AU - Richter, Alex G AU - Scott, Aaron AU - Thickett, David R TI - Vitamin D status: a U-shaped relationship for SARS-CoV-2 seropositivity in UK healthcare workers AID - 10.1136/bmjresp-2022-001258 DP - 2022 Sep 01 TA - BMJ Open Respiratory Research PG - e001258 VI - 9 IP - 1 4099 - http://bmjopenrespres.bmj.com/content/9/1/e001258.short 4100 - http://bmjopenrespres.bmj.com/content/9/1/e001258.full SO - BMJ Open Resp Res2022 Sep 01; 9 AB - Background There is increasing evidence that vitamin D (VD) deficiency may increase individuals’ risk of COVID-19 infection and susceptibility. We aimed to determine the relationship between VD deficiency and sufficiency and COVID-19 seropositivity within healthcare workers.Methods The study included an observational cohort of healthcare workers who isolated due to COVID-19 symptoms from 12 May to 22 May 2020, from the University Hospitals Birmingham National Health Service Foundation Trust. Data collected included SARS-CoV-2 seroconversion status, serum 25(OH)D3 levels, age, body mass index (BMI), sex, ethnicity, job role and comorbidities. Participants were grouped into four VD categories: (1) Severe VD deficiency (VD<30 nmol/L); (2) VD deficiency (30 nmol/L ≤VD<50 nmol/L); (3) VD insufficiency (50 nmol/L ≤VD<75 nmol/L); (4) VD sufficiency (VD≥75 nmol/L).Results When VD levels were compared against COVID-19 seropositivity rate, a U-shaped curve was identified. This trend repeated when participants were split into subgroups of age, sex, ethnicity, BMI and comorbidity status. Significant difference was identified in the COVID-19 seropositivity rate between VD groups in the total population and between groups of men and women; black, Asian and minority ethnic (BAME) group; BMI<30 (kg/m2); 0 and +1 comorbidities; the majority of which were differences when the severely VD deficient category were compared with the other groups. A larger proportion of those within the BAME group (vs white ethnicity) were severely VD deficient (p<0.00001). A larger proportion of the 0 comorbidity subgroup were VD deficient in comparison to the 1+ comorbidity subgroup (p=0.046).Conclusions Our study has shown a U-shaped relationship for COVID-19 seropositivity in UK healthcare workers. Further investigation is required to determine whether high VD levels can have a detrimental effect on susceptibility to COVID-19 infection. Future randomised clinical trials of VD supplementation could potentially identify ‘optimal’ VD levels, allowing for targeted therapeutic treatment for those at risk.Data are available upon reasonable request. The data sets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.