Introduction A historical cohort study in workers occupationally exposed to chrysotile was set up in the town of Asbest, the Russian Federation, to study their cause-specific mortality, with a focus on cancer.

Objective Describe the Asbest Chrysotile Cohort established in 2013.

Methods Cohort enrolment was based on employment records from JSC Uralasbest chrysotile mine and processing factories. Exposure assessment was based on detailed occupational histories extracted from company archives and personal workbooks linked to > 90,000 measurements, and conversion factors derived using a subset of parallel dust/fibre measurements. This resulted in yearly dust and fibre estimates for each employed calendar year. Vital status was ascertained from multiple sources including company records, the Pension Fund, the Federal Migration Service, and Civil Act Registration Office providing the date and cause of death of those deceased in Sverdlovsk Region.

Results The cohort comprises 22,463 men and 13,374 women working ≥1 year between 01/01/1975 and 31/12/2010 in JSC Uralasbest and followed until 31/12/2015. Cumulative exposure of exposed women was higher than for men (49 mg/m3 dust years and 33 fibres/cm3 years vs. 31 mg/m3dust years and 19 fibres/cm3years). At the end of follow-up, 52% of the cohort was alive, 36% deceased, and 12% censored at last date known to be alive in the Sverdlovsk Region. For those who died the mean age at death was 59.4 years for men and 66.5 for women. The most frequent underlying cause of death for all was circulatory diseases, followed by external causes and cancer in men, and cancer and external causes in women. Cancer mortality was dominated by lung cancer in men and breast cancer in women.

Conclusion The cohort is unique in its size, long follow-up, and substantial proportion of female workers. The cohort is relatively young, and the mortality patterns follow those of the Russian population. Risk analyses are underway.