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

Navigating the Depths of Cardiovascular Effects on Submariners

The environment of the submariner is inherently endowed with several health risk factors, namely confinement, inactivity, caloric excess, and circadian disruption, among others, during deployment. Metabolic disturbances, increased cardiovascular risk, and sleep deprivation are associated with interrupting circadian rhythms due to routines contributing to physiological and cognitive abnormalities. Additionally, submariners face vitamin deficits of vitamin D and vitamin B12 due to little exposure to sunlight and poor nutrition. It is associated with cardiovascular dysfunctions, endothelial dysfunctions, metabolic abnormalities, and a greater cardiovascular risk. Moreover, high obesity prevalence has been noted among submariners. Such cases were attributed to leptin resistance, body fat deposits, and lifestyle statistics. Other risk factors to the cardiovascular system, like changes in heart rate variability and heart functions, have been witnessed. These health challenges can be mitigated by adopting proactive steps to address submariners' specific health needs. Such measures should include the prevention of stable circadian rhythms, vitamin intake, lifestyle, and cardiovascular health. By addressing these issues, submariners' well-being will be upheld, and their vulnerability to cardiovascular diseases and other health-related complications will be lessened.

Self-reported vitality and health status are higher in Dutch submariners than in the general population

Introduction

Living aboard submarines has a potential negative effect on health. Although studies have evaluated specific health hazards and short-term outcomes, long-term health effects have not been investigated in this population.

Methods

Veteran submariners were contacted through the veterans' society and administered a World Health Organisation validated questionnaire (SF-36) assessing their physical, emotional, and social functioning. Scores were compared with those of the general (reference) population and scores in veteran submariners were differentiated by rank, time at sea and time in service. Statistical analyses were performed using the Wilcoxon signed rank and Kruskal-Wallis tests.

Results

Of the 1,025 submariners approached in December 2019, 742 (72.4%) completed and returned the questionnaire before July 2020. All 742 were men, of median age 68 (interquartile range [IQR] 59-76) years (range 34-99 years). Of these subjects, 10.3% were current smokers, 64.4% were former smokers and 23.7% had never smoked. Submariners scored significantly better (P < 0.001) than the general population on all eight domains of the SF-36. Except for 'pain' and 'change in health status over the last year', scores for all domains decreased with age. Scores were not significantly affected by smoking status, rank, service, and time at sea.

Conclusions

Dutch veteran submariners have better self-reported vitality and health status than the general Dutch population. Rank, service, and time at sea did not significantly affect scores of Dutch submariners.

Energy Expenditure and Changes in Body Composition during Submarine Deployment-An Observational Study "DasBoost 2-2017"

The present study was designed to objectively assess the effects of 3-months submarine deployment on behavioural and metabolic determinants of metabolic health. In 13 healthy, non-obese volunteers, we using stable isotope dilution, and plasma and urinary biochemistry to characterize metabolic health before and after a 3-month submarine deployment. Volunteers worked in 6-h shifts. After deployment, we observed reduced fat-free mass (mean ± SD, -4.1 ± 3.3 kg, p = 0.003) and increased adiposity (21.9 ± 3.2% fat mass to 24.4 ± 4.7%, p = 0.01). Changes in fat-free mass were positively associated with physical activity (+0.8 kg per 0.1 increase in PAL, p = 0.03). The average physical activity level was 1.64 ± 0.26 and total energy expenditure during deployment was 2937 ± 498 kcal/d, while energy intake was 3158 ± 786 kcal/d. Fasting glucose (p = 0.03), and triglycerides (p = 0.01) declined, whereas fasting free fatty acids increased (p = 0.04). Plasma vitamin D and B12 concentrations decreased (-14%, p = 0.04, and -44%, p = 0.001, respectively), and plasma calcium, and magnesium increased (+51%, p = 0.01, and +5%, p = 0.02). Haemoglobin was unchanged, but haematocrit decreased (-2.2 ± 2.1%, p = 0.005). In conclusion, submarine deployment impairs fat-free mass maintenance and promotes adiposity. High physical activity may prevent the decline in fat-free mass. Our study confirms the need to counteract Vitamin D and B12 deficiencies, and suggests impairments in erythrocyte metabolism.

Energy Expenditure and Changes in Body Composition during Submarine Deployment-An Observational Study "DasBoost 2-2017"

The present study was designed to objectively assess the effects of 3-months submarine deployment on behavioural and metabolic determinants of metabolic health. In 13 healthy, non-obese volunteers, we using stable isotope dilution, and plasma and urinary biochemistry to characterize metabolic health before and after a 3-month submarine deployment. Volunteers worked in 6-h shifts. After deployment, we observed reduced fat-free mass (mean ± SD, −4.1 ± 3.3 kg, p = 0.003) and increased adiposity (21.9 ± 3.2% fat mass to 24.4 ± 4.7%, p = 0.01). Changes in fat-free mass were positively associated with physical activity (+0.8 kg per 0.1 increase in PAL, p = 0.03). The average physical activity level was 1.64 ± 0.26 and total energy expenditure during deployment was 2937 ± 498 kcal/d, while energy intake was 3158 ± 786 kcal/d. Fasting glucose (p = 0.03), and triglycerides (p = 0.01) declined, whereas fasting free fatty acids increased (p = 0.04). Plasma vitamin D and B12 concentrations decreased (−14%, p = 0.04, and −44%, p = 0.001, respectively), and plasma calcium, and magnesium increased (+51%, p = 0.01, and +5%, p = 0.02). Haemoglobin was unchanged, but haematocrit decreased (−2.2 ± 2.1%, p = 0.005). In conclusion, submarine deployment impairs fat-free mass maintenance and promotes adiposity. High physical activity may prevent the decline in fat-free mass. Our study confirms the need to counteract Vitamin D and B12 deficiencies, and suggests impairments in erythrocyte metabolism.

THE ASSESSMENT OF COMORBID PATHOLOGY IN CLEAN-UP WORKERS OF THE ACCIDENT CONSEQUENCES AT THE CHORNOBYL NPP HAVING CARDIOVASCULAR DISEASES

OBJECTIVE

Analysis of comorbid pathology based on the use of methods for its quantitative assessment in personswho were exposed to radiation because of the Chornobyl accident.

MATERIALS AND METHODS

Comorbid pathology was studied in 608 men, including 420 clean-up workers (CW) of theaccident consequences at the Chornobyl NPP (main group) and 188 non-irradiated persons (control group - CG). Allpatients had cardiovascular diseases as their main pathology and were examined in the cardiology department ofthe NRCRM hospital during 2011-2019. The groups did not differ by age, either at the beginning of the accident orat the time of their last examination. Patients of both groups before the accident were practically healthy peopleand were not registered at the dispensary. The Cumulative Illness Rating Scale (CIRS) was used to quantify comorbid pathology.

RESULTS

Comorbid pathology was detected in 418 CW (99.5 %) and 183 patients of CG (99.3 %). The total score inCW (10.3 ± 2.9) units significantly (р = 0.000) exceeded the same index in non-irradiated patients (8.8 ± 3.0) units,as well as the mean number of CIRS categories, whose level severity was 1 point (3.3 ± 1.7 vs. 2.6 ± 1.5, р = 0.000),2 points (1.8 ± 1.0 vs. 1.6 ± 1.0, p = 0.032) and 3-4 points (1.2 ± 0.8 vs. 1.0 ± 0.9, р = 0.062). In contrast, the meanvalue of the categories with zero score, i.e. without diseases, was more common in CG (7.8 ± 1.8 vs. 8.8 ± 1.7,р = 0.000). The most common pathology in CW and CG were heart (98.3 % vs. 94.7 %, р < 0.05) and vascular diseases(92.9 % vs. 87.8 %, р > 0.05), followed by diseases of nervous system (79.0 % vs. 57.4 %, р <0.001), musculoskeletal system and skin (69.8 % vs. 56.9 %, р < 0.01), endocrine (56.0 % vs. 49,5 %, р > 0.05) and the respiratory system (53.8 % vs. 53.7 %, р > 0.05) and liver (51.2 % vs. 36.2 %, р < 0.001), which were detected more than in halfpatients of the main group. Diseases of the kidneys (3.3 % vs. 4.8 %, р > 0.05) and lower gastrointestinal tract(3.3 % vs. 0.5 %, р < 0.01) were quite rare. The incidence of the other four CIRS categories was 18.6-34 %. The totalscore in subgroups with different ages varied in descending order of mean values as follows: CW > 65 years (10.5 ± 2.9)units, CW < 65 years (9.9 ± 2.8) units, CG > 65 years (9.5 ± 2.8) units and CG < 65 years (7.8 ± 2.9) units with significant differences both between age subgroups in each of the groups and between CW and CG older subgroups.

CONCLUSIONS

Quantitative assessment of comorbidity by CIRS showed that in persons irradiated during their emergency work due to the Chornobyl accident, the incidence of combined pathology of such organ systems as cardiovascular, nervous, endocrine, hematopoietic, urogenital, musculoskeletal, gastrointestinal, liver and kidneys wassignificantly higher than in non-irradiated patients. In irradiated patients, the course of comorbid pathology wasmore severe for each system and in general, reflecting higher values of the total CIRS score. Both among CW andnon-irradiated controls, higher values of the total comorbidity score were observed in patients 65 years and older,compared with younger individuals. In both age subgroups of CW the total score was higher than in patients of thecontrol group.

Effect of Radiance-Dimmer Devices Simulating Natural Sunlight Rhythm on the Plasma Melatonin Levels and Anxiety and Depression Scores of the Submarine Personnel

Objective: Not perceiving circadian shifts of sunlight due to living in enclosed environments may have deleterious effects on mental health and plasma parameters. This study aimed to determine the effect of dim regulation on the submarine personnel of Iranian Navy forces by radiating devices according to natural circadian sunlight shifts. Also, this study aimed to investigate the impact of mimicking sunlight circadian by artificial radiance luminating devices on the serological and psychological measures of submarine personnel. Method : Participants were randomly assigned to experimental and control groups in this non-randomized controlled trial. There were 26 participants in each group, and they were all male aged 21-29 years. Both groups were living in the submarine underground hall, with 120 meters 2 area with constant radiance with the same intensity. The experimental group had been given extra lighting devices with changing radiance intensity according to the natural sunlight circadian cycles. Plasma melatonin levels and depression and anxiety scores were determined before and after the experiment for both groups. Minnesota Multiphasic Personality Inventory (MMPI) and Cattell's Anxiety Scale Questionnaire (IPAT) were used to measure depression and anxiety, respectively. Results: Findings indicate that the plasma melatonin levels (-16.2±13.6 vs 8.0±9.3 mg/dL, respectively; p<0.001), depression scores (-6±6 vs 3.9±5.4, respectively; p<0.001), and anxiety scores (-1±1.2 vs 0.73±1.04, respectively; p<0.001) significantly reduced in the experimental group compared to the control group. Conclusion: Using radiance dimmers, with a radiance intensity regularity according to the sunlight, is effective in improving psychiatric and plasma parameters and can be used in closed occupational environments such as underground environments and submarine halls.