Non-communicable diseases among subcontract and primary workers involved in decontamination after the fukushima daiichi nuclear power plant accident: an observational study

OBJECTIVE: Evidence on the population-level burden of major non-communicable diseases (NCDs) among Fukushima decontamination workers is limited, and it remains unclear whether subcontracted employment, a potential marker of employment-related vulnerability, is associated with NCD prevalence and health risk awareness. We therefore compared the prevalence of NCDs by employment status. METHODS: We conducted a cross-sectional study using health checkup data from 2,790 workers (2011-2017). Data concerning hypertension, diabetes mellitus, and dyslipidemia were evaluated, along with the workers' self-reported awareness of diagnosis or treatment. Employment status was categorized as subcontracted worker or prime contractor worker. Group differences were assessed using Welch's t-tests and chi-squared tests, and quantile regression adjusted for age and sex. RESULTS: The study included a total of 2,790 decontamination workers, of whom 1,716 were subcontracted workers (median age, 51 years; range, 18-82). The subcontracted workers had higher mean systolic blood pressure, a lower prevalence of self-reported hypertension, and higher blood glucose levels in extreme cases. CONCLUSIONS: The subcontracted workers had higher systolic blood pressure despite lower self-reported hypertension. Future studies should investigate factors contributing to differences in NCD prevalence between subcontracted and prime contractor workers, such as lower self-awareness and barriers to healthcare access among subcontracted workers.