Cardiovascular hospitalizations among Danish seafarers: a nationwide register study

Background: Cardiovascular disease (CVD) is a leading cause of morbidity worldwide, influenced by several risk factors. Seafarers are exposed to CVD risk factors due to their working environment and lifestyle. We investigated hospitalizations among seafarers compared with the Danish working population. Material and methods: This register-based cohort study used Danish nationwide registers. Seafarers aged 18–64 years were compared to the working population for all-cause and CVD inpatient hospitalizations between 1994 and 2016. Negative binomial regression, stratified by sex and adjusted for age, birth cohort, and education, provided incidence rate ratios (IRRs) with 95% confidence intervals (CIs). Further analyses included specific diagnoses and type of seafarer. Results: Male seafarers had increased rates of all-cause (IRR = 1.05, 95% CI: 1.04–1.07) and CVD (IRR = 1.10, 95% CI: 1.06–1.14) hospitalizations. The CVD associations persisted among those working on passenger ferries (IRR = 1.26, 95% CI: 1.18–1.34) and cargo ships (IRR = 1.06, 95% CI: 1.01–1.12). Further analysis revealed increased hospitalizations among male seafarers for pulmonary heart diseases, cerebrovascular diseases, diseases in arteries, arterioles, and capillaries, and diseases in veins, lymphatic vessels, and lymph nodes. Overall, female seafarers did not have increased hospitalization rates but females working on passenger ferries had an increased all-cause hospitalization rate (IRR = 1.04, 95% CI: 1.00–1.08), while those on cargo ships had a decreased rate (IRR = 0.95, 95% CI: 0.92–0.98). Conclusions: Male seafarers had higher hospitalization rates than the reference population, whereas the pattern varied among female seafarers.