Environmental asbestos exposure in childhood and risk of mesothelioma later in life: a long-term follow-up register-based cohort study

To examine the risk of malignant mesothelioma (MM) in former pupils who attended primary school near an asbestos cement plant.A cohort of 12 111 former pupils, born 1940-1970, was established from individual historical records from four primary schools located at a distance of 100-750 m in the prevailing wind direction from an asbestos cement plant operating from 1928 to 1984 in Aalborg, Denmark. The school cohort and a comparison cohort consisting of 108 987 gender and 5-year frequency-matched subjects were followed up (2015) for MM in the Danish Cancer Registry. Using Cox regression, HRs were estimated for the incidence of MM. Adjustments for occupational and familial asbestos exposure were made with a job exposure matrix. An SIR analysis including latency periods testing the cancer incidence rate was performed with the comparison cohort as the reference rate.The median person-years of follow-up were 62.5 years in the school cohort and 62.2 years in the comparison cohort. There were 32 males and 6 females of the former pupils who developed MM during the follow-up: HRmale 7.01 (95% CI 4.24 to 11.57), HRfemale 7.43 (95% CI 2.50 to 22.13). Those who attended school 250 m north of the plant had the highest HR for MM, 10.65 (95% Cl 5.82 to 19.48). No significant trend between school distance and risk of MM was established (p=0.35).Our results suggest that boys and girls who attended schools and lived in the neighbourhood of an asbestos cement plant later in life have a significantly increased risk of MM.