Mortality from cardiovascular disease in a cohort of Swedish seafarers

Eva Andersson,Helena P. Eriksson,Karl Forsell

doi:10.1007/s00420-019-01486-5

Abstract

PurposeThe aim of this study was to investigate whether Swedish seafarers have increased mortality from cardiovascular disease compared with the general population.MethodsRegister-based longitudinal cohort study of 85,169 Swedish seafarers where all subjects with a minimum of 30 days service registered in the Seafarers’ Register 1985–2013 were included. Mortality from coronary heart disease, cerebrovascular disease and total mortality for comparison were analysed by calculating standardised mortality ratios (SMRs), with 95% confidence intervals (CIs). Mortality was further analysed by gender, duty on board, type of vessel, and over time.ResultsThere was no increase in either mortality from cardiovascular disease or total mortality for seafarers, who had worked solely on passenger ferries. Mortality from coronary heart disease and cerebrovascular disease was increased for male seafarers < 46 years old who had worked on different types of vessels, SMR 1.48 (95% CI 1.06–2.01) and SMR 1.93 (95% CI 1.16–3.02), respectively. Analysing the seafarers by duty showed significantly increased SMRs from coronary heart disease in males aged < 46 of the categories “deck crew” and “engine officer/crew (ever)”. The total mortality for seafarers who had worked on different types of vessels was increased; males SMR 1.05 (95% CI 1.02–1.09) and females SMR 1.17 (95% CI 1.04–1.30), but decreased over time.ConclusionsNo increased mortality on passenger ferries but younger male seafarers on different types of vessels had increased mortality from cardiovascular disease. Reduction of hazardous occupational exposures onboard is important, such as shift work, stress and noise.

Highlights

Previous studies have shown increased mortality and morbidity in seafarers compared with individuals in land-based occupations (Brandt et al 1994, Rafnsson & Gunnarsdottir 1994; Jensen 1996; Mellbye & Carter 2017)
The total mortality for the seafarers having served on different types of vessels as one group decreased; it was significantly increased for male seafarers in the age groups 46–55 and 56–65 years (SMR 1.27 and standardised mortality ratios (SMRs) 1.30, respectively)
Our study shows that there was an increased mortality from coronary heart disease (CHD) and cerebrovascular disease in relatively younger male seafarers having worked on different types of vessels, especially those with several years of service

Summary

Introduction

Previous studies have shown increased mortality and morbidity in seafarers compared with individuals in land-based occupations (Brandt et al 1994, Rafnsson & Gunnarsdottir 1994; Jensen 1996; Mellbye & Carter 2017). Seafarers have increased risk factors for CVD, such as smoking, obesity and lack of physical exercise (Pougnet et al 2013; Oldenburg 2014; Nittari et al 2019). Other potential common risk factors at sea for CVD are shift work (Torquati et al 2018), noise exposure (Skogstad et al 2016; Forsell et al 2017) and psychosocial stress (Theorell et al 2016; Forsell et al 2017). Danish studies have found increased frequencies of hypertension and metabolic syndrome among seafarers (Tu & Jepsen 2016; Moller Pedersen & Jepsen 2013). The metabolic syndrome is likely linked, among other things, to lack of physical activity, as well as stress and shift work

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