Hospital contacts for chronic diseases among danish seafarers and fishermen: a population-based cohort study

Abstract

Objectives: Seafarers' and fishermen's working conditions may impact on their lifestyle and health. Standardized hospital contact ratios (SHCRs) were compared in two time periods and the relative risks of hospital contact as a function of employment time were estimated.

Methods: Cohorts of all Danish seafarers (officers and non-officers) registered by the Danish Maritime Authority (DMA) 1989-98 and fishermen retrieved from a pension registry 1989-98 were linked to the nationwide Occupational Hospitalization Registry (OHR) and followed up for incident diseases in two five-year time periods, from 1 January 1994 and 1 January 1999, respectively, using rates specific for age and calendar time for the entire Danish workforce as a reference.

Results: The SHCRs for lung and cardiovascular diseases were high for non-officers. Among male officers, the SHCR for diabetes was high in the 1999 cohort and the SHCR for chronic heart diseases was statistically significantly higher in the 1999 than in the 1994 cohort. For both time periods high SHCR values were found for bronchitis, emphysema, cancer of the lung, alcohol-related liver diseases, and diabetes among male non-officers, and lung cancer among male officers. Among female non-officers, a high SHCR for skin melanomas was seen. Among fishermen high SHCRs for bronchitis, emphysema, lung cancer, and Raynaud's syndrome were found in both cohorts. No duration-response pattern was observed in any of the analyses, which may reflect health- and lifestyle-related selection into the trades or a healthy worker effect.

Conclusions: Danish seafarers, especially short-term employees, had an elevated risk of hospitalization for lifestyle-related diseases.