Study design

A cross-sectional study was conducted among medical students at the Faculty of Medicine, at the author’s institution. Since the study involved an anonymous questionnaire and all invited students could decline participation, separate approval from the institutional bioethics committee was not required according to institutional regulations.

Data were collected via an anonymous online survey sent to the university mailboxes of 2614 medical students in early March 2024, with responses gathered throughout March and April 2024. The survey included questions on demographics, chronic diseases (e.g., depression, thyroid disease, migraine, atopic dermatitis, hypertension, asthma), spinal posture defects (e.g., scoliosis, pathological curvatures), spinal conditions (e.g., discopathy, intervertebral disc herniation, spinal overload pain syndrome), smoking history, physical exercise frequency and duration, maintenance of proper spine posture while sitting, approximate daily sitting duration, past and present LBP occurrence, duration, intensity (measured using a Numeric Rating Scale, NRS), and analgesic use.

The Oswestry Low Back Pain Disability Index (ODI) was used to assess the disability resulting from LBP. The Polish version of this questionnaire validated on the Polish population was used [17]. The Polish version of Patient Health Questionnaire (PHQ-9) validated for the Polish adult population, which includes DSM-4 and DSM-5 criteria for diagnosing depression, was used to evaluate the prevalence of depression in the study group [18]. Point prevalence of LBP was defined as the presence of LBP during the data collection period. The duration of LBP was classified as acute, subacute, or chronic based on cut-off values of 4 and 12 weeks, respectively [3].

The study adhered to the STROBE Statement guidelines.

Participants

The inclusion criteria for participants were as follows: active participation in university activities, good understanding of the Polish language, and consent to participate in the study. The exclusion criteria included a history of spinal surgery. Participants with spinal conditions and posture defects were not excluded from the study.

As the curriculum of medicine in Poland includes 6 years, with the first 3 years focusing on pre-clinical courses and the latter three including mainly classes in hospitals, participants were divided into subgroups based on their sex and participation in pre-clinical or clinical activities.

Data analysis

The data were statistically analyzed using PQStat Software (2023), PQStat v.1.8.6, Poznan, Poland. The Shapiro-Wilk test indicated that all continuous variables did not follow a normal distribution. Differences between sexes and between pre-clinical and clinical years of study were assessed using Mann-Whitney and χ² tests. All nominal variables met Cochran’s condition after the χ² tests and were presented as counts and percentages. Univariate logistic regression identified potential LBP risk factors, which were then included in multivariate logistic regression to determine independent risk factors. The fit of the multivariate model was assessed using the Hosmer-Lemeshow goodness-of-fit test (χ² = 6.5, p = 0.59), as well as Cox and Snell (R² = 0.1488) and Nagelkerke (R² = 0.21) pseudo R² measures. Statistical significance was set at p < 0.05.

Prevalence

LBP is one of most common medical problems; a systematic review by Hoy et al. estimated that point prevalence in the global population was 18.3 ±11.7% [1]. In this study, 70.95% of participants experienced pain at the time of survey completion (point prevalence), which is higher than in other studies on medical students, where point prevalence was lower – for example, 25.4% in a study from Austria [19], 25.6% from Bangladesh [7], 40.5% from Saudi Arabia [20], 25.4% from Malaysia [21], 17.2% from Serbia [8], and 32.5% from India [11]. There are studies from Sudan [22] and Saudi Arabia [9, 23], where prevalence of LBP was respectively 69.3%, 66.4% and 94%; however, those studies did not specify the time frame of LBP occurrence in the question.

In our research, about 53.5% of respondents had chronic LBP (pain lasting longer than 12 weeks). Again, this is considerably higher than in other studies which measured prevalence of chronic LBP in medical student populations – 19.5% in Malaysia [21], 12.4% in Serbia [8], and 15.5% in Austria [19]. The discrepancies between our findings and others may be attributed to the fact that our surveys were collected between March and April, during the exam period, when students tend to sit and study extensively. Differences in educational demands, cultural attitudes toward physical discomfort, and health behavior norms in Poland versus other regions could also influence LBP prevalence. Additionally, the other studies were conducted in the pre-COVID period, while ours was in the post-COVID era, which may also be an influencing factor, as it could be hypothesized that the pandemic period adversely affected the frequency of back pain occurrence, especially considering that the literature suggests this [24].

Depression and LBP

Evidence predominantly indicates that chronic back pain can trigger or exacerbate symptoms of depression, and vice versa [12, 25–27]. While some studies suggest that depression may not act as a direct risk factor for spinal pain [28], this view is in the minority compared to numerous studies supporting a strong link between the two. Our study demonstrated an association between LBP and depressive symptoms, aligning with other research conducted among medical students [11, 29, 30]. It can be assumed that that altered pain perception, decreased physical activity, and heightened inflammatory responses can all contribute to the prevalence and severity of LBP in those experiencing depression. Additionally, medical students experiencing mental distress may engage less in physical activity, compounding their risk of developing or worsening LBP.

Sedentary lifestyle

Sedentary behaviors during work and leisure are linked to a moderately increased risk of LBP in all age groups [10]. Unsurprisingly, in this study nearly two thirds of students were sitting for 8 h or more, and there was a strong association between prolonged sitting and LBP disability. Our data further suggest that addressing sedentary behavior in medical curricula could help mitigate LBP risks. In contrast, a Saudi Arabian study reported only 16.1% sitting over 8 h and about 30% sitting between 4 to 8 h, also linking over 8 h of sitting to increased LBP risk [9]. In Bangladesh, 31% sat for more than 6 h daily, showing a significant correlation with increased LBP [7]. A Brazilian study found a median sitting time of 8 h but no significant correlation with back pain [30]. Similarly, an Austrian study with a median sitting time of 12 h found no correlation with LBP [19]. These differences may stem from varying lifestyles, posture habits, and approaches to physical activity among medical students in different countries.

Posture

In our study, only 2.2% maintained the correct posture, and about half of the respondents said that they tried to maintain it most of the time. Many studies focusing on medical students have found a significant correlation between maintaining good posture and reducing back pain [8, 11, 30]. In a study from Saudi Arabia [9], 44.3% of respondents indicated that one of their methods for reducing back pain is maintaining correct posture and in a study from Belgrade it was around 54% [8]. In our study we identified that not maintaining proper spine posture during sitting may potentially contribute to the development of LBP; however, it is not an independent risk factor.

Sex

In nearly every study conducted on medical students, females were more predisposed to experience spinal pain [7, 8, 11, 30, 31]. An exception was noted in a study from Saudi Arabia, where no correlation between sex and spinal pain was demonstrated [9]. In this series, females had a higher risk of LBP and higher degrees of disability. This could be related to the fact that women in our survey were less likely to engage in physical exercise and maintain proper spine position during sitting; however, there is not sufficient evidence to support this hypothesis, and logistic regression models were unable to demonstrate female sex as a risk factor contributing to the development of LBP.

BMI and exercise

In the general population, body mass index (BMI) appears to play an important role, as overweight and obesity are strongly associated with seeking medical care for low back pain and chronic low back pain according to literature [32]. However, in our study, BMI was not associated with LBP, although it is worth mentioning that the majority of respondents had BMI within the normal range. Most authors demonstrated increased risk of LBP in students with higher BMI [7, 9, 20]; however, this was not confirmed in all studies [11].

A meta-analysis of 61 randomized controlled trials on LBP and exercising found that exercise therapy seems to be slightly effective at decreasing pain and improving function in adults with chronic LBP, however, it does not have a significant effect on acute LBP [33]. Most of the studies on medical students support the thesis that the prevalence of LBP is lower in those who exercise more frequently [7–9, 19, 21, 23]. Studies from Brazil [30] and India [11] did not find a correlation between exercising and LBP; similarly, this study did not identify lack of physical exercises as a risk factor contributing to the development of LBP. The inconsistency in findings may be due to differences in exercise types, intensity, and frequency, as well as individual variability in physical fitness levels and lifestyle habits among study populations.

Pain intensity and painkillers

In our study, the median pain intensity was rated as 3 on the Numeric Rating Scale, which aligns with findings from other studies. Specifically, the median NRS score was 3 in a study from China [31], 4 in a study from Brazil [30], and 3.91 in a study from Saudi Arabia [9].

Regarding the use of painkillers for managing LBP, 7.5% of respondents in our study reported taking painkillers due to the occurrence of LBP. This rate is identical to that found in a study from Saudi Arabia [9]. In contrast, a study from Brazil reported that 56.1% of those with LBP would take painkillers occasionally, and 43.9% would take them from once a week to daily [30]. Meanwhile, a study from Bangladesh found that 22.1% of respondents admitted to taking opioid medications for LBP [7]. Differences in the frequency of taking painkillers might stem from cultural differences or awareness and education about potential harms of using those medications.

Clinical years and pain

Our research indicates that students in the pre-clinical stages of their education suffer from more intense back pain and spend more time sitting compared to students in clinical stages. This increased severity of LBP in pre-clinical students could be attributed to extended periods of sitting during study sessions and lectures, which are less frequent in the more physically active clinical years. Furthermore, multiple studies have shown a notable correlation between the year of study and the occurrence of musculoskeletal pain in medical students [20, 21, 34, 35]. This was however challenged by other authors [7, 30, 36].