The tendency of diseases among seamen during the last fifteen years in Japan

What is known about cardiovascular diseases among seafarers: A systematic scoping review and quality assessment

BACKGROUND

Seafarers are at an increased risk of developing cardiovascular diseases (CVDs), potentially due to a stressful working environment and behavioral risk factors. To develop better prevention strategies, it is important to elucidate the extent of this risk. Therefore, we conducted a systematic literature review on CVD in seafarers.

METHOD

We conducted systematic searches in five databases. All studies investigating CVDs among occupational seafarers, published in articles or conference papers, were eligible for inclusion. The identified records were screened and reviewed by two independent researchers, who also evaluated the methodological quality of the included studies.

RESULTS

Three thousand nine hundred and seventeen records qualified for screening, and 55 were eligible for inclusion. Most of the studies were observational, including cohort, frequency, incidence or prevalence studies, and review of case records. Around half were assessed at risk of biased findings. Participants in the studies were primarily from North America or the European continent and work onboard transportation vessels. Many studies investigated CVDs as a cause of death, focusing on conditions such as CVD, ischemic heart disease, and myocardial infarction. Frequency of CVD conditions varied but indicate that seafarers face a greater risk compared to the reference populations or control groups. Environmental factors were mainly investigated as risk factors.

CONCLUSION

Our results indicate a higher risk of CVDs among seafarers compared to reference or control groups. However, due to the variable quality of the evidence, well-designed studies are needed to establish the causes of cardiovascular mortality and morbidity in seafarers and to investigate behavioral aspects of cardiovascular risk.

Interactions between Human Gut Microbiome Dynamics and Sub-Optimal Health Symptoms during Seafaring Expeditions

During long ocean voyages, crew members are subject to complex pressures from their living and working environment, which lead to chronic diseases-like sub-optimal health status. Although the association between dysbiotic gut microbiome and chronic diseases has been broadly reported, the correlation between the sub-optimal health status and gut microbiome remains elusive. Here, the health status of 77 crew members (20-35 years old Chinese, male) during a 135-day sea expedition was evaluated using the shotgun metagenomics of stool samples and health questionnaires taken before and after the voyage. We found five core symptoms (e.g., abnormal defecation frequency, insomnia, poor sleep quality, nausea, and overeating) in 55 out of 77 crew members suffering from sub-optimal health status, and this was termed "seafaring syndrome" (SS) in this study. Significant correlation was found between the gut microbiome and SS rather than any single symptom. For example, SS was proven to be associated with individual perturbation in the gut microbiome, and the microbial dynamics between SS and non-SS samples were different during the voyage. Moreover, the microbial signature for SS was identified using the variation of 19 bacterial species and 26 gene families. Furthermore, using a Random Forest model, SS was predicted with high accuracy (84.4%, area under the concentration-time curve = 0.91) based on 28 biomarkers from pre-voyage samples, and the prediction model was further validated by another 30-day voyage cohort (accuracy = 83.3%). The findings in this study provide insights to help us discover potential predictors or even therapeutic targets for dysbiosis-related diseases. IMPORTANCE Systemic and chronic diseases are important health problems today and have been proven to be strongly associated with dysbiotic gut microbiome. Studying the association between the gut microbiome and sub-optimal health status of humans in extreme environments (such as ocean voyages) will give us a better understanding of the interactions between observable health signs and a stable versus dysbiotic gut microbiome states. In this paper, we illustrated that ocean voyages could trigger different symptoms for different crew member cohorts due to individual differences; however, the co-occurrence of high prevalence symptoms indicated widespread perturbation of the gut microbiome. By investigating the microbial signature and gut microbiome dynamics, we demonstrated that such sub-optimal health status can be predicted even before the voyage. We termed this phenomenon as "seafaring syndrome." This study not only provides the potential strategy for health management in extreme environments but also can assist the prediction of other dysbiosis-related diseases.

Probiotics maintain the gut microbiome homeostasis during Indian Antarctic expedition by ship

Ship voyage to Antarctica is a stressful journey for expedition members. The response of human gut microbiota to ship voyage and a feasible approach to maintain gut health, is still unexplored. The present findings describe a 24-day long longitudinal study involving 19 members from 38th Indian Antarctic Expedition, to investigate the impact of ship voyage and effect of probiotic intervention on gut microbiota. Fecal samples collected on day 0 as baseline and at the end of ship voyage (day 24), were analyzed using whole genome shotgun sequencing. Probiotic intervention reduced the sea sickness by 10% compared to 44% in placebo group. The gut microbiome in placebo group members on day 0 and day 24, indicated significant alteration compared to a marginal change in the microbial composition in probiotic group. Functional analysis revealed significant alterations in carbohydrate and amino acid metabolism. Carbohydrate-active enzymes analysis represented functional genes involved in glycoside hydrolases, glycosyltransferases and carbohydrate binding modules, for maintaining gut microbiome homeostasis. Suggesting thereby the possible mechanism of probiotic in stabilizing and restoring gut microflora during stressful ship journey. The present study is first of its kind, providing a feasible approach for protecting gut health during Antarctic expedition involving ship voyage.

Self-Reported Modifiable Risk Factors of Cardiovascular Disease among Seafarers: A Cross-Sectional Study of Prevalence and Clustering

BACKGROUND

Cardiovascular diseases (CVD) are the major cause of work-related mortality from diseases onboard ships in seafarers. CVD burden derives mainly from modifiable risk factors. To reduce the risk factors and the burden of CVD onboard ships in seafarers, it is important to understand the up-to-date prevalence of modifiable risk factors. The primary purpose of this study was to assess the prevalence and clustering of self-reported modifiable CVD risk factors among seafarers. We have also explored the association between socio-demographic and occupational characteristics and reported modifiable CVD risk factor clustering.

MATERIALS AND METHODS

A cross-sectional study was conducted among seafarers from November to December 2020 on board ships. In total, 8125 seafarers aged 18 to 70 were selected from 400 ships. Data were collected using a standardized and anonymous self-reported questionnaire. The prevalence value for categorical variables and mean differences for continuous variables were compared using chi-square and independent sample t-tests. Multinomial logistic regression models were performed to identify independent predictors for modifiable CVD risk factor clustering.

RESULTS

Out of a total of 8125 seafarers aged ≥18 years on selected vessels, 4648 seafarers volunteered to participate in the survey, with a response rate of 57.2%. Out of 4318 participants included in analysis, 44.7% and 55.3% were officers and non-officers, respectively. The prevalence of reported hypertension, diabetes, current smoking and overweight or obesity were 20.8%, 8.5%, 32.5%, and 44.7%, respectively. Overall, 40%, 20.9%, 6% and 1.3% of the study participants respectively had one, two, three and four modifiable CVD risk factors. Older age (51+ years) (odds ratio (OR): 3.92, 95% confidence interval (CI): 2.44-6.29), being non-officers (OR: 1.36, 95% CI: 1.09-1.70), job duration (10-20 years) (OR: 2.73, 95% CI: 2.09-3.57), job duration (21+ years) (OR: 2.60, 95% CI: 1.79-3.78), working 57-70 h per week (OR: 2.03, 95% CI: 1.65-2.49) and working 71+ h per week (OR: 3.08, 95% CI: 2.42-3.92) were independent predictors for at least two self-reported modifiable CVD risk factor clustering.

CONCLUSION

The results of our study demonstrate that more than four in six (68.5%) seafarers aged between 19 and 70 years have at least one of the modifiable CVD risk factors. Therefore, CVD prevention and modifiable risk factors reduction strategies targeting high-risk groups should be designed and implemented on board ships.

Incidence of occupational injuries and diseases among seafarers: a descriptive epidemiological study based on contacts from onboard ships to the Italian Telemedical Maritime Assistance Service in Rome, Italy

OBJECTIVES

Workers at sea have high mortality, injuries and illnesses and work in a hazardous environment compared to ashore workers. The present study was designed to measure the incidence of occupational injuries and diseases among seafarers and quantify the contribution of differences in rank and job onboard on seafarers' diseases and injuries rates.

DESIGN

Descriptive epidemiological study.

SETTING AND PARTICIPANTS

This study's data were based on contacts (n=423) for medical requests from Compagnie Maritime d'Affrètement/Compagnie Générale Maritime (CMA-CGM) container ships to the Italian Telemedical Maritime Assistance Service in Rome from 2016 to 2019, supplemented by data on the estimated total at-risk seafarer population on container ships (n=13 475) over the study period.

OUTCOME MEASURES

Distribution of injuries by anatomic location and types of diseases across seafarers' ranks and worksites. We determined the incidence rate and incidence rate ratio (IRR) with a 95% CI.

RESULTS

The total disease rate was 25 per 1000 seafarer-years, and the overall injury rate was 6.31 per 1000 seafarer-years over the 4 years study period. Non-officers were more likely than officers to have reported gastrointestinal (IRR 2.12, 95% CI 1.13 to 4.26), dermatological (IRR 3.66, 95% CI 1.27 to 14.42) and musculoskeletal (IRR 2.25, 95% CI 1.11 to 5.05) disorders onboard container ships. Deck workers were more likely than engine workers to be injured in the wrist and hand (IRR 3.25, 95% CI 1.19 to 10.23).

CONCLUSIONS

Rates of reported injury and disease were significantly higher among non- officers than officers; thus, this study suggests the need for rank-specific preventative measures. Future studies should consider risk factors for injury and disease among seafarers in order to propose further preventive measures.

Work-related musculoskeletal disorders among occupational fishermen: a systematic literature review

BACKGROUND

Commercial fishing constitutes an increased risk of musculoskeletal disorders (MSD), as it consists of heavy workloads and uncontrollable strenuous settings. The aims of this systematic review were to describe the prevalence of MSD among occupational fishermen and to identify risk factors for onset work-related MSD.

METHODS

All studies investigating MSD in occupational fishermen were systematically identified and reviewed. Searched databases were PubMed/MEDLINE, EMBASE and CINAHL. Two independent researchers performed the quality assessments of the studies.

RESULTS

From 292 articles identified, 16 articles consisting of 13 studies were suitable for inclusion. Prevalence of overall MSD ranged from 15% to 93%. The only consistent work-related risk factor was 'working part time', while other risk factors, such as vessel and job type showed conflicting results.

CONCLUSION

MSDs in occupational fishermen are common across countries. Variations observed in MSD prevalence might be due to differences in methodology, populations and definitions of MSD. Evidence on work-related risk factors for MSD is sparse and most studies were of poor methodological quality. Only working part time was identified as a consistent risk factor for MSD possibly caused by a healthy worker effect. There is a need for investigating causality in longitudinal studies, including both active and retired fishermen to better understand the complexity of MSD.

PROSPERO REGISTRATION NUMBER

CRD42020147318.

An Investigation into the Health Risks Associated with the Noise and Vibrations on Board of a Boat—A Case Study on the Danube River

This paper studies the noise and vibrations transmitted to the crew of a pusher with eight barges sailing upstream the Danube River, between Cernavoda and Drobeta, with a staff consisting of a captain, one coxswain, one mechanic and three sailors. The research was conducted over a one-week period in August 2018. The navigation time was 24/24 h and the seafarers’ schedule was 4/8. Determinations were made on three different workers: Coxswain, mechanic and sailor. The meteorological parameters and the Danube river levels, the sound level and the transmitted vibrations, as well as the body temperature and blood pressure of the subjects were measured. The periods of activity and sleep were analyzed by means of an actigraph. Our research findings indicate that people worked overtime, slept less than necessary and, generally, did not observe the official program. The noise (LEP,d = 92 dB) and vibration levels (a total exposure A(8) = 4.1 m/s2) also contributed to the sleep disorder. Such effects were accompanied by increased body temperature and blood pressure. Synthesizing, it can be concluded that: The peak (acrophase) of the work capacity was from 9:00 to 11:00 and from 17:00 to 19:00, which represent the maximum efficiency periods. More specifically, the highest mental performances were recorded in the morning, while the maximum physical ones were to be seen in the afternoon. The minimum efficiency period was from 13:00 to 15:00. Decreases in the work capacity were identified at 23:00 (reasonably low level) and 3:00 (extremely low level).

Injury, illness, and disability risk in American seafarers

BACKGROUND

Seafarers are an understudied and essential workforce, isolated from medical care. This study describes injuries, illness, and risk factors for resultant disability in one shipping company with a majority of American seafarers.

METHODS

The study used a telemedicine database of injury and illness incidence in seafarers, and applied descriptive statistical methods and logistic regression modeling.

RESULTS

Illnesses were more frequently reported than injuries (860 vs 479). The overall injury rate was 113 per 1000 person-years, and the overall illness rate was 211 per 1000 person-years. Seafarer ratings had higher risk for disability compared to officers (OR = 1.60; 95%CI 1.17, 2.18), and incidents on dry cargo ships (OR = 2.70; 95%CI 1.49, 4.91) and articulated tug-barges (ATBs) (OR = 2.21; 95%CI 1.26, 3.86) had higher disability risk compared to container vessels.

CONCLUSION

Additional research in this vital American workforce may be useful to confirm these findings forming a basis for preventive interventions.

"Injury, illness, and work restriction in merchant seafarers"

BACKGROUND

Research on seafarer medical conditions at sea is limited. This study describes the frequency and distribution of seafarer injury and illness at sea, and explores potential risk factors for resultant lost work.

MATERIALS AND METHODS

The study analyzed a telemedicine database of 3,921 seafarer medical cases between 2008 and 2011 using descriptive statistics and logistic regression.

RESULTS

There were over twice as many illness cases (n = 2,764, 70.5%) as injury (n = 1,157, 29.5%) cases. Disability was more often secondary to illness (n = 646, 54.3%), predominantly from gastrointestinal, dermatologic, and respiratory conditions. Logistic regression revealed age, rank, and worksite as potential risk factors for lost work.

CONCLUSIONS

This study emphasizes illness as a significant problem occurring in seafarers at sea. Future research should further elucidate risk factors for illness, as well as injury, to inform preventive measures and reduce seafarer disability.

Metagenomic sequencing reveals altered metabolic pathways in the oral microbiota of sailors during a long sea voyage

Seafaring is a difficult occupation, and sailors face higher health risks than individuals on land. Commensal microbiota participates in the host immune system and metabolism, reflecting the host's health condition. However, the interaction mechanisms between the microbiota and the host's health condition remain unclear. This study reports the influence of long sea voyages on human health by utilising a metagenomic analysis of variation in the microbiota of the buccal mucosa. Paired samples collected before and after a sea-voyage were analysed. After more than 120 days of ocean sailing, the oral microbial diversity of sailors was reduced by approximately 5 fold, and the levels of several pathogens (e.g., Streptococcus pneumonia) increased. Moreover, 69.46% of the identified microbial sequences were unclassified microbiota. Notably, several metabolic pathways were dramatically decreased, including folate biosynthesis, carbohydrate, lipid and amino acid pathways. Clinical examination of the hosts confirmed the identified metabolic changes, as demonstrated by decreased serum levels of haemoglobin and folic acid, a decreased neutrophil-to-lymphocyte ratio, and increased levels of triglycerides, cholesterol and homocysteine, which are consistent with the observed microbial variation. Our study suggests that oral mucosal bacteria may reflect host health conditions and could provide approaches for improving the health of sailors.

Coronary risks among seafarers aboard German-flagged ships

OBJECTIVES

Cardiovascular diseases belong to the major causes of maritime service disablement (approximately 18%). The aim of this study was to investigate the frequency of coronary risk factors in seamen on vessels sailing under the German flag and to assess the risk of coronary heart disease (CHD) dependent on job-related factors.

METHODS

Within a medical surveillance program, a cross-sectional study with interview, blood sampling, and blood pressure measurements was conducted among a total of 205 male seafarers sailing under the German flag (response 84.9%). Due to missing blood analysis, 13 seamen were excluded. The predicted 10-year risk of an acute coronary event of a study subgroup of 45 German seafarers was compared to the corresponding risk of a sample of the German working population (PROCAM study).

RESULTS

In the total sample (n = 161), 55 seamen (34.2%) had at least three CHD risk factors. The most prominent independent CHD risk factors in seafarers were hypertension (49.7%), high triglycerides (41.6%), older age (39.8%), and smoking (37.3%). Compared with non-Europeans, European seafarers were about twice as likely to have more than three risk factors after adjusting for age [OR 2.4 (95% CI 1.01-4.55)]. Particularly engine room officers and galley/operating staff were at a higher coronary risk. After standardizing for age, the German seamen investigated showed a similar predicted 10-year CHD risk as the German population of about the same age working ashore of the PROCAM study.

CONCLUSIONS

The CHD risks in seafarers should be reduced by low-fat diets, anti-smoking campaigns and blood pressure control/treatment. In spite of the seafarers' regular medical surveillance examination, their CHD risk was comparable to a reference population working ashore. Our results support the hypothesis that working on vessels may augment the risk of CHD.