Self-assessment of physical state of Navy corps
The self-reported rates of common diseases in two fleets were sorted in descending order as following: muscle and skeletal system disease, respiratory disease, skin disease, oral disease, digestive disease, and ophthalmic and ear-nose-throat diseases. Such a trend was also found in the surface fleet or submarine force of Fleet A, or Fleet B. As to the submarine branch, the self-reported rates of all the common diseases were significantly higher in Fleet B than Fleet A (Table 1). In Fleet A, skin and respiratory diseases were significantly higher in the surface fleet than that in the submarine force, and other common diseases exhibited similar trend without significance.
The self-reported rate of each disease was obviously increased with the age (Figure 1). The frequencies of digestive, respiratory and skin diseases were rising steadily. Muscle and skeletal system disease kept about the frequency of 60% under age 30, while over age 30, the frequency approximately increased up to 80%. Two peaks of the frequency of oral disease occurred in the age group of 26-30 and 36-40, respectively. The self-reported rate of ophthalmic and ear-nose-throat diseases increased a lot over age 40.
We further investigated the self-reported rates of infectious diseases that the corps had in the past six months. Generally, the most common infectious diseases were influenza and diarrhea with the frequencies of 65.1% and 48.6%, respectively. Moreover, the corps with age of 21-25 was high risk group predisposed to these two common diseases, in which the frequencies of influenza and diarrhea were 42.4% and 46.2%, respectively. Other infectious diseases according to the frequency in descending order were malaria, hepatitis, and pulmonary tuberculosis. The self-reported rates of infectious disease in the submarine force of Fleet A and Fleet B were similar (P>0.05,Figure 2). In Fleet A, the frequencies of influenza and diarrhea in the submarine force were much higher compared to that of surface fleet (P<0.001). This indicated that airtight cabin of submarine force can effectively increase the possibilities of pathogen transmission. Specially, Fleet B, contributing 70% to the total malaria patients, reported more patients than the submarine force of Fleet A (2.7% (7/264) vs 1.3% (1/76), P=0.690).
Self-assessment of psychological health
The psychological problems were reported in 47.3% of the corps, and the frequency was definitely increased with the age. In the age group of 21-25, the reported frequency reached to 47.1%. The age group of 31-35 took much higher reported rate of 62.5%. All the personnel with the age of 41-45 reported psychological problems, though it was partially because of small sample size. The total of 10% of the soldiers reported to be ever got psychological problems. Although the rate of ever being sick with psychological problems in the submarine force of Fleet A was higher than that of Fleet B (16.7% vs 8.1%, P=0.028), the self-reported rate of the existing psychological problem of the former was much lower than that of the latter (29.5% vs 52.6%, P<0.001). This indicated some intervention in Fleet A may be responsible for this change. Furthermore, in Fleet A, the frequency of the existing psychological problem of the submarine force was significantly lower than that of the surface fleet (29.5% vs 46.8%, P=0.019).
The events reflecting current psychological state were also exhibited in Table 1. Over half of the personnel suffered from trouble sleeping. Of those with the existing psychological problem, 70.15% was reported to have trouble in sleeping. More “trouble sleeping” (56.3% vs 38.5%, P=0.007) and “being awakened by horrible dream” (48.7% vs 33.3%, P=0.02) existed in Fleet B than that of the submarine force of Fleet A. In Fleet A, more “trouble sleeping” (56.4% vs 38.5%, P=0.037) while less “being worried about training injury” (48.1% vs 53.9%, P=0.004) were significantly reported in the surface fleet compared to the submarine force.
Table 1
Self-reported rates of physical or psychological problems in the Navy corps during March to September, 2014
Problems
|
Frequency of Fleet A (%)
|
Frequency of Fleet B (%)
|
Total (%)
|
surface
|
submarine
|
submarine
|
Physical
|
|
|
|
|
Muscle and skeletal system
|
53.3
|
49.4
|
63.6**
|
59.0
|
Respiratory system
|
45.3*
|
35.0
|
50.0**
|
46.3
|
Skin disease
|
41.3*
|
22.1
|
45.3**
|
40.2
|
Oral cavity
|
25.3
|
18.2
|
38.8**
|
32.4
|
Digestive system
|
17.3
|
16.9
|
34.1**
|
27.8
|
Ophthalmic and Ear-nose-throat diseases
|
13.3
|
7.8
|
18.2**
|
15.4
|
Psychological
|
|
|
|
|
Trouble sleeping
|
56.4*
|
38.5
|
56.3**
|
53.1
|
Being awakened by horrible dream
|
44.9
|
33.3
|
48.7**
|
45.2
|
Special scene flashed in the mind
|
48.7
|
43.6
|
50.5
|
51.0
|
Being worried about training injury
|
48.1*
|
53.9
|
66.4
|
61.1
|
Being affected by sailing over 7 days
|
58.4
|
49.4
|
42.6
|
47.0
|
Being confident with the mission assigned by the supervisor
|
90.8
|
92.3
|
87.8
|
89.2
|
Being friendly with others
|
96.2
|
98.7
|
97.8
|
97.7
|
* P<0.05, When compared the surface fleet to the submarine force of Fleet A
* * P<0.05, When compared the submarine force of Fleet A to that of Fleet B
|
Although 89.2% of those surveyed were confident with the mission assigned and 97.7% of people reported to be friendly with others, the average score of self-evaluation on psychological health was relative lower (77.83±13.61). The self-evaluated score of Fleet A was higher than that of Fleet B (81.70±12.08 vs 75.75±13.96, P<0.001).The surface fleet reported significantly higher score than all the submarine force (80.48±12.11 vs 77.34±13.86, P<0.001). For submarine force, the score of Fleet A was much higher than that of Fleet B (82.17±11.49 vs 78.30±11.45, P<0.001). To further clarify the relationship between the evaluation score and related risk factors, we defined the personnel scored under 60 as the unsatisfied group and that over 95 as the satisfied group. The unsatisfied group enrolled 25 personnel, including 1 in the surface of Fleet A, 2 in the submarine force of Fleet A, and 22 in Fleet B. The satisfied group enrolled 22 personnel, including 14 of Fleet A (6 in the surface; 8 in the submarine force) and 8 in Fleet B. Particularly, the average types of disease each person reported in the unsatisfied group were almost double than those in the satisfied group (2.8 vs 1.4, P=0.04), which indicated physical health was closely correlated to psychological health.
Risk factors related to health problems
To further explore the risk factors related to the health of the corps, the potential items related to living condition, working environment, living habits and health education were listed (Table 2). Closed working condition of long term, humid climate of costal location, heavy maintenance of vessels were considered by the submarine force as the top reasons to cause disease. Whereas in the surface force, closed working condition of long term, humid climate of costal location, poor dietetic hygiene and shortage of fresh water supply were the top reasons. Except for the items in the questionnaire, the surface fleet made supplementary items affecting health: 1) no time to be hospitalized due to busy work; 2) too short time of exercise; 3) only physical examination without further therapy;4) unqualified fresh water and tableware.
Table 2
The cognition of the corps about potential causes of disease.
Problems
|
Frequency of Fleet A (%)
|
Frequency of Fleet B (%)
|
Total (%)
|
surface
|
submarine
|
submarine
|
Long-term closed working condition
|
53.2
|
35.4
|
65.9
|
57.9
|
Humid climate of costal location
|
44.3
|
38.0
|
63.0
|
54.9
|
Heavy maintenance of vessels
|
30.4
|
48.1
|
59.6
|
52.1
|
Over-training
|
13.9
|
13.9
|
37.8
|
29.0
|
Lack of health knowledge and consciousness of health care
|
21.5
|
24.1
|
30.7
|
27.8
|
No regular physical examination
|
19.0
|
20.3
|
34.2
|
27.6
|
Poor dietetic hygiene, shortage of fresh water supply
|
34.2
|
13.9
|
26.3
|
25.5
|
Shortage of specialist, such as otolaryngologist, dermatologist
|
15.2
|
13.9
|
31.5
|
25.2
|
Complicated referral systems
|
13.9
|
10.1
|
32.6
|
25.0
|
Unhealthy living and dietary habits
|
16.5
|
15.2
|
19.3
|
18.0
|
Simple living facilities
|
10.1
|
11.4
|
4.4
|
13.6
|
Others
|
32.9
|
8.9
|
15.9
|
11.0
|
The corps of different age group complained different top risk factor. Heavy maintenance of vessels was taken as the top factor to affect health by age group of 16-20 and 31-40, while closed working condition of long term was the top factor by age group of 21-30 and overloaded training was the top factor by age group of 41-45. About 77% of the corps considered both the working and living conditions should be improved.
The unhealthy living habits reported was ranked by smoking, alcohol intake, drinking strong tea, chewing arecas, biting nails, which were all traditional unhealthy habits in modern China11 (Figure 3A). Such a trend was similar either for the surface fleet or the submarine force. Fleet B reported significant higher frequency of drinking alcohol than the submarine force of Fleet A (58.0% vs 34.8%, P=0.01). We also investigated the approaches the corps acquired the knowledge of health care. The most popular way was medical doctors and nurses either for different fleets or branches, followed by network, families and friends, professional books, and popular magazines (Figure 3B). In addition, about 76.1% of the corps considered it necessary to set up the specialists including otolaryngologist and dermatologist when executing a mission on the sea. Above indicate that health workers including the specialist played an important and irreplaceable role to perform health care and health promotion for the Navy.
To investigate the unexpected factors which may affect performing medical service, the total of 20 Navy medics in Fleet A was personally interviewed, including 10 had bachelor degree and 10 had senior college degree. The most serious problem reported is the members can’t be quickly adaptable to their job and working environment after graduation, which was mainly because their major was clinic medicine other than family medicine. Some of the medics just graduated even could not succeed in performing intravenous injection although they might join the complex surgery in the hospital during their intern. So the corps preferred nurses to young medical doctors for medical need, which made the medics frustrated for a long time even suffered from mental disease at the end. Thus family doctor was the first urgent medical need for Chinese Navy. The second problem is the air pollution caused by disinfection of ultraviolet radiation, especially in the confined space without good ventilation like the submarine. Most of the vessels made by iron and steel also limited the extensive application of the effective disinfector acetic acid peroxide.