- Baseline questionnaire completed by about 225,000 participants.
- Almost 1,400 variables describing social and economic demographics, personal and family health histories, medications, sleep patterns, alcohol and tobacco use, physical activity and environmental exposures.
- Follow-up questionnaire completed in March 2018. It asked participants for an update on their health and additional questions around e-cigarettes and marijuana use, mental health and over-the-counter drugs. Data from the Follow-up Questionnaire are now available.
- The Work History Questionnaire was completed in December, 2019.
- Regular follow-up questionnaires will be conducted to track changes in overall health.
- The COVID-19 Questionnaire was completed November 13, 2020. Data from the COVID-19 Questionnaire are now available.
- The COVID-19 Antibody Study Questionnaire and the first of three blood spot sample collections was completed in June 2021. Data from this first timepoint are now available.
Read the OHS Cohort Profile Paper in the International Journal of Epidemiology.