To investigate whether seafarers in Norway who were declared unfit for service at sea or received a time-limited health certificate had a higher risk of acute somatic hospital admissions compared with those who received a full health certificate.

Registry-based cohort study.

Seafarers in Norway who presented to a seafarer’s doctor to obtain a health certificate between 2018 and 2019, as required for work aboard Norwegian vessels. The study was conducted within Norway’s publicly funded healthcare system.

Norwegian seafarers aged 18–70 years who underwent medical examinations (n=43 758), including n=5452 females (12.5%).

Acute somatic hospital admission within 2 years of medical examination. HRs were estimated using Cox regression models in two separate time periods (0–3 months and 3–24 months), with adjustment for possible confounding from age, gender, level of education and centrality of residence (proximity to healthcare services).

The crude risk of acute somatic hospital admissions was higher for individuals who received a declaration of unfitness, as compared with those who received a full health certificate, in both follow-up periods: 0–3 months (HR=5.13, 95% CI: 3.27 to 8.04) and 3–24 months (HR=2.63, 95% CI: 2.07 to 3.34). Similarly, those with time-limited health certificates had a higher risk in both periods: 0–3 months (HR=2.02, 95% CI: 1.39 to 2.93) and 3–24 months (HR=2.45, 95% CI: 2.15 to 2.79). Adjustment of the analyses for socio-demographic factors did not change the effect estimates substantially.

These findings highlight the importance of comprehensive and continuous health assessments to help prevent adverse health outcomes and ensure safety at sea, particularly among vulnerable subgroups of seafarers.