In this study, the overall prevalence of MSP among Chinese medical students during home protection was found to be 40.2% (n = 345; 95% CI 36.9%-43.4%), which is similar to the results of two studies on the prevalence of MSP among Chinese medical students in 2005 and 2022 during their normal school life, with prevalence rates of 46.9% and 41.4%, respectively.[8, 9] The data revealed no increase in the overall prevalence of MSP or in regions of the body (with the highest prevalence still in the neck and shoulders). Rosario Ferlito et al. and Muna A. Salameh et al. used cross-sectional studies to investigate the prevalence of MSP among physiotherapy students in Sicily and medical students at Al-Balqa Applied University who had adopted a home protection policy for 6–12 and 3 months during the COVID-19 epidemic. They found that the prevalence of MSP was 73.1% and 75.9% respectively.[16, 17] In a study of a public medical university in southern Brazil prior to the COVID-19 epidemic, Bruna Xavier Morais et al. found that the prevalence of MSP in normal school life for medical undergraduates was 74.9%; also in normal school life prior to the COVID-19 epidemic, Ilke Coskun Benlidayi et al. found that the prevalence of MSP among medical students was 75.8% in the Department of Physical Medicine and Rehabilitation of Cukurova University (Adana, Turkey).[5, 7] These studies seem to show that there is no significant change in the prevalence of MSP among medical students during home protection. However, the curricula of medical universities in different countries vary considerably, which may lead to differences in the lifestyles of medical students at school, and thus the prevalence of MSP is not comparable. Therefore, continuous monitoring of MSP prevalence and risk factors for the same country and region, or even for the same university, would be helpful in the development of prevention policies for MSP in medical students.
Sex was a risk factor for the occurrence of MSP, (OR = 1.391, 95CI 1.006–1.922, P = 0.046 < 0.05), with women having a 39.1% higher risk of MSP occurrence than men, which is consistent with most studies.[2, 5, 12, 18] Studies have shown that for certain region of the body, men have a higher risk of MSP than women. For example, Fahad AA investigated the occurrence of MSP in the lower back among 1163 medical students from five medical schools in Saudi Arabia and found that the risk was higher in men than in women.[19] Thus, the overall prevalence of MSP and its risk factors are different from the prevalence in a specific region of the body.
This study found that regular physical exercise in normal school life was significantly effective in the prevention of MSP compared to the intensity, frequency, and duration of physical exercise per session. Risk of MSP was 64.8% higher in those with irregular physical exercise in their normal school life than in those with regular physical exercise (OR = 1.648, 95CI 1.157–2.347, P = 0.006 < 0.05). A study conducted by Gidey Gomera Weleslassie et al. at Mekelle University, Ethiopia, which included 422 people, found that physical exercise was effective in preventing neck and shoulder pain;[13] Graciana de Azambuja et al. gave a mouse animal model a certain amount of time of swimming every day for continuous 21 days. The results showed that the prevalence of MSP in the experimental group was significantly lower than that in the control group without any exercise. At the same time, the levels of receptors and inflammatory factors associated with MSP were measured in the serum of the mice, and the results further revealed that daily swimming can effectively reduce the increase of inflammatory factors caused by persistent fatigue in the relevant areas and prevent the activation of pathways that cause MSP, thereby preventing the occurrence of MSP.[20] This study found that changes in the intensity, frequency or duration per session of physical exercise weren’t risk factors of MSP over a certain period of time (25-45days for home protection), which is supported by similar studies.[2, 21] Most previous studies on the correlation between physical exercise and MSP have focused on the intensity and frequency of physical exercise, duration of physical exercise per session, or the variation of the three, and have often reached different conclusions.[2, 21–24] A careful analysis of the methods of these studies shows that researchers tend to focus on the average value of the frequency of physical exercise per week and duration of physical exercise per session neglecting the importance of even distribution in seven days per week. However, many studies on the risk factors for MSP in workers of different occupations have shown that regular and planned physical exercise during off-work hours (leisure time) is effective in preventing the occurrence of MSP.[25, 26] This study confirms for the first time that this assertion also holds true for Chinese medical students and Michael et al.'s study of risk factors for MSP in 145 medical undergraduates at a medical university in South Africa reached conclusions consistent with this study.[27] Therefore, we recommend that medical students engage in regular physical exercise during their leisure time in school life, and medical schools develop policies to support this!
Less than 6 hours of sleep per day during home protection was a risk factor for MSP (OR = 1.474,95CI 1.020–2.131, P = 0.039 < 0.05), with a 47.4% higher risk compared to those who received 6–8 hours of adequate sleep per day. Although the interaction between sleep quality and MSP is now well established, the exact mechanisms involved are unclear.[28] Some studies suggest that sleep deprivation causes the release of inflammatory factors that affect the regulation of the hypothalamic-pituitary-adrenal axis, reducing the secretion of dopamine and thus causing MSP;[29] others assume that sleep deprivation causes increased sensitivity to pain sensation, decreased willingness to physical exercise and a range of psychological problems such as anxiety, depression and fear of pain, which are mutually reinforcing with MSP.[30, 31]
Although this study provides some important findings, there are some limitations that need to be mentioned. First, this is a cross-sectional study and causality is unknown. Therefore, longitudinal studies are a valuable direction for the future. Second, some variables were self-reported and could affect the reliability of the data. Finally, this study was conducted in a city in the northeast of Jiangsu Province, eastern China, which may only represent areas with similar characteristics, limiting the generality of the findings. Despite these limitations, this study contributes to provide new clues for the search of risk factors for MSP and alternative solutions for the prevention.