Mortality and cancer incidence in the UK glass reinforced plastics manufacturing industry: a cohort study.

Objectives: According to the International Agency for Research on Cancer, styrene is probably carcinogenic for lymphohaematopoietic neoplasms, with insufficient evidence for other cancer sites. We compared mortality and cancer incidence (for the first time) in a UK cohort occupationally exposed to high levels of styrene to that of the general population of England and Wales.

Methods: The follow-up for mortality ran from 1969 to 2022, while the follow-up for cancer incidence ran from 1971 to 2020. Standardised mortality ratios (SMRs) and standardised incidence ratios (SIRs) were calculated for cancer and non-cancer outcomes. Additional analyses compared mortality and cancer incidence with respect to the median age at and time since first exposure.

Results: A total of 1319 males contributed 53 687 person-years of follow-up in the all-cause mortality analysis. Mortality analyses did not indicate any clear increased risks. There was an indication of higher mortality of cancers of the trachea, bronchus or lung (SMR=1.30 (95% CI 0.99 to 1.70)). Mortality from lymphatic and haematopoietic neoplasms was elevated in those first exposed younger than 25 years of age (SMR=2.20 (95% CI 1.12 to 3.92)). The SIR analysis suggested reduced cancer incidence for all malignant neoplasms combined (SIR=0.85 (95% CI 0.76 to 0.96)). The incidence of lymphatic and haematopoietic neoplasms, especially myeloid proliferations and neoplasms, was elevated in those first exposed before 25 years old.

Conclusions: This study provides some limited evidence in support of styrene being a cause of lymphohaematopoietic, particularly myeloid neoplasms and lung cancers. This cohort is contributing to an ongoing international study to help clarify these associations.