The association between submarine service and multimorbidity: a cross-sectional study of Korean naval personnel

Objective We aimed to estimate the prevalence of multimorbidity (>= 2 chronic health problems) among Korean submariners and to evaluate the association between submarine service and multimorbidity and disease burden. Study design and setting This cross-sectional study included 590 naval personnel who visited a Korean primary care clinic during 2014-2015. Data regarding general characteristics and morbidities were collected from medical records, and disease burden was assessed using the Cumulative Illness Rating Scale (CIRS). Multiple logistic regression analysis was used to evaluate the association between submarine service and multimorbidity and disease burden. Results The prevalence of multimorbidity was 11.7% among 180 non-submariners and 32.2% among 410 submariners. The prevalence of multimorbidity and the CIRS scores gradually increased with age. Submarine service was associated with higher risk of multimorbidity and disease burden compared with non-submarine service even after adjusting for age, alcohol consumption, smoking status and naval rank. However, a dose-response relationship was not evident between the duration of submarine service and the risk of multimorbidity as well as high disease burden. Conclusions Submarine service was significantly associated with a higher risk of multimorbidity and greater disease burden than non-submarine service. This finding suggests that multidimensional and holistic healthcare approaches are needed for submariners.