Prevalence of musculoskeletal symptoms, excessive daytime sleepiness, and fatigue in the crew members of a U.S. Navy ship

Abstract

This epidemiological, cross-sectional, questionnaire-based study has two goals. The first goal is to assess the prevalence of musculoskeletal (MSK) symptoms, fatigue levels, and use of caffeinated beverages in a sample of active duty personnel in the U.S. Navy. Second, the study seeks to explore the associations among musculoskeletal symptoms, reported sleep, daytime alertness, and fatigue levels. During the weigh-in portion of their semiannual Physical Readiness Test in Spring 2014, crewmembers of a U.S. Navy aircraft carrier were invited to complete an anonymous survey. The survey contained questions pertaining to demographics, exercise frequency, average sleep duration, caffeine consumption, the Epworth Sleepiness Scale (ESS), the Nordic Musculoskeletal Symptoms Survey, and the Fatigue Severity Scale (FSS). We had 767 respondents; approximately, a 30% response rate. Two-thirds of the sample was male. The average age was 25.4 ± 5.94 years; ranging from 18 to 49. Approximately 43% of the sample was overweight and 7% obese. At least one type of caffeinated beverage was used by 88.3% of the participants. Participants reported receiving approximately six hours of sleep per day while at sea; more than 50% of them rated their sleep as less than needed and 31.8% reported increased daytime sleepiness (ESS scores > 10). Approximately 9% of the participants reported an FSS score greater than or equal to 5, suggesting elevated fatigue levels. Approximately 58% of the respondents reported at least one MSK symptom in the last 12 months, 44% reported at least one symptom in the last seven days, and 20.4% reported that MSK symptoms prevented them from carrying out their normal activities. Regarding the 12-month prevalence, the lower back (39.5%) and knees (33.6%) were the two body parts most frequently reported for MSK symptoms. Symptoms in these two body parts were also the most frequently reported as preventing participants from normal activities. Older crewmembers were more likely to report MSK symptoms, and females reported more MSK symptoms than males. The occurrence of MSK symptoms was associated with elevated fatigue levels and excessive daytime sleepiness. Compared to crewmembers without MSK symptoms, crewmembers with MSK symptoms are more likely to report elevated daytime sleepiness (g=0.26 – 0.39), increased levels of fatigue (g=0.54 – 0.59) and are more likely to use sleep-promoting medications. Crewmembers reporting MSK symptoms were more likely to consume caffeinated beverages.