Environmental asbestos exposure and occupational asbestos exposure increase the risk of several types of cancer, but the role of such exposures for haematological malignancies remains controversial. We aimed to examine the risk of haematological malignancies: first, in subjects exposed early in life, independently of any occupational exposure occurring later; second, in subjects exposed occupationally. We established an environmentally exposed cohort from four schools located near the only former asbestos cement production plant in Denmark. We identified nearly all pupils in the seventh grade and created an age and sex-matched 1:9 reference cohort from the Danish Central Population Register. Participants were born 1940–1970 and followed up in national registers until the end of 2015. Occupational asbestos exposure was assessed for all participants using two different job exposure matrices. The school cohort included 12,111 participants (49.7% girls) and the reference cohort 108,987 participants. Eight subgroups of haematological malignancy were identified in the Danish Cancer Registry. These cases were analysed for combined overall haematological malignancy, a combined subgroup of lymphomas and a combined subgroup of leukaemias. The data were analysed using Cox regression (hazard ratios (HR)) including other cancers and death as competing risks. Haematological malignancy was identified in 1125 participants. The median follow-up was 49.3 years (0.1–63.4). Early environmental asbestos exposure was not associated with an increased risk of haematological malignancy. Long-term occupational asbestos exposure was associated with overall haematological malignancy (HR 1.69, 95% CI 1.04–2.73); in particular for the leukaemia subgroup (HR 2.14, 95% CI 1.19–3.84). This large follow-up study suggests that long-term occupational asbestos exposure is associated with increased leukaemia risk. However, further studies are needed to confirm these observations.

环境性石棉接触和职业性石棉接触会增加几种癌症的风险，但是此类接触对血液系统恶性肿瘤的作用仍存在争议。我们旨在检查血液系统恶性肿瘤的风险：首先，在生命早期接触的受试者中，与以后发生的任何职业接触无关。第二，在职业暴露的对象中。我们从丹麦唯一的前石棉水泥生产厂附近的四所学校建立了一个环境暴露人群。我们确定了几乎所有七年级的学生，并从丹麦中央人口登记处创建了一个年龄和性别匹配的1：9参考队列。参加者出生于1940年至1970年，并在国家注册处接受随访，直到2015年底。使用两种不同的工作暴露矩阵对所有参与者的职业石棉暴露进行了评估。该学校队列包括12,111名参与者（49.7％的女孩），参考队列108,987名参与者。在丹麦癌症登记处确定了八个血液恶性肿瘤亚组。分析了这些病例的总体血液学恶性肿瘤，淋巴瘤的合并亚组和白血病的合并亚组。使用Cox回归（危险比（HR））分析数据，包括其他癌症和死亡作为竞争风险。在1125名参与者中发现了血液系统恶性肿瘤。中位随访时间为49.3年（0.1-63.4）。早期环境石棉暴露与血液系统恶性肿瘤风险增加无关。长期职业性接触石棉与总体血液系统恶性肿瘤相关（HR 1.69，95％CI 1.04–2.73）。特别是对于白血病亚组（HR 2.14，95％CI 1.19–3.84）。这项大规模的后续研究表明，长期职业性接触石棉与白血病风险增加有关。但是，需要进一步的研究来确认这些观察结果。