Background: Risk factors for severe COVID-19 include older age, male sex, obesity, Black or Asian ethnicity and underlying medical conditions. Whether these factors also influence susceptibility to developing COVID-19 is uncertain. Methods: We undertook a prospective, population-based cohort study (COVIDENCE UK) from 1st May 2020 to 5th February 2021. Baseline information on potential risk factors was captured by an online questionnaire. Monthly follow-up questionnaires captured incident COVID-19. We used logistic regression models to estimate multivariable-adjusted odds ratios (aORs) for associations between potential risk factors and odds of COVID-19. Results: We recorded 446 incident cases of COVID-19 in 15,227 participants (2.9%). Increased odds of developing COVID-19 was independently associated with Asian/Asian British vs. White ethnicity (aOR 2.28, 95% CI 1.33-3.91), household overcrowding (aOR per additional 0.5 people/bedroom 1.26, 1.11-1.43), any vs. no visits to/from other households in previous week (aOR 1.31, 1.06-1.62), number of visits to indoor public places (aOR per extra visit per week 1.05, 1.02-1.09), frontline occupation excluding health/social care vs. no frontline occupation (aOR 1.49, 1.12-1.98) and raised body mass index (BMI) (aOR 1.50 [1.19-1.89] for BMI 25.0-30.0 kg/m2 and 1.39 [1.06-1.84] for BMI >30.0 kg/m2 vs. BMI <25.0 kg/m2). Atopic disease was independently associated with decreased odds (aOR 0.75, 0.59-0.97). No independent associations were seen for age, sex, other medical conditions, diet, or micronutrient supplement use.Conclusions: After rigorous adjustment for factors influencing exposure to SARS-CoV-2, Asian/Asian British ethnicity and raised BMI were associated with increased odds of developing COVID-19, while atopic disease was associated with decreased odds.