Sars-Cov-2 antibody titer 3 months post-vaccination is affected by age, gender, smoking and vitamin D.

Context Vaccination against Sars-Cov-2 is in full swing during COVID-19 pandemic. One of the efficient methods to evaluate response to vaccination is the assessment of humoral immunity by measuring Sars-Cov-2 antibody titer. Identification of factors that affect the humoral response is important so as to ameliorate the responses to vaccination or identify vulnerable groups that may need vaccination boosters. Objective We investigated the effect of anthropometric parameters (age, BMI), smoking, diabetes, statin use hypertension and levels of 25(OH)D and DHEAS to the Sars-Cov-2 antibody titer. Methods In this longitudinal observational cohort study 712 subjects were tested for Sars-Cov-2 antibodies 3 months after the second dose of BNT162b2 vaccine. Multiple linear regression analysis was performed to identify which factors are associated with the antibody titer. Results We identified age to be negatively associated with antibody titer (p=0.0073) and male sex (p=0.0008). However, interaction of age and gender was significant (p<0.0001) highlighting the finding that only after the age of 40 years men had lower antibody levels than women. DHEAS, an aging marker, was not associated with the antibody titer. Smoking was also associated with low antibody titer (p=0.0008) while overweight or obese subjects did not have different antibody response compared to normal weight individuals. Although diabetic and hypertensive subjects trended towards lower antibody titer, this association was not statistically significant. Replete vitamin D levels were associated with higher antibody titers (p=0.00422). Conclusions Age, male sex and smoking negatively affects antibody titer while 25(OH)D is associated with increased Sars-Cov-2 antibody titers.