Back pain in the midwifery profession in northern Poland

Population

The study group consisted of 208 women who were active midwives and anonymously completed a questionnaire on complaints of back pain and the nature of their work. Data was collected between January 2023 and January 2024.

Selection criteria

Eligible for the study were those over 18 years of age, active and licensed as midwives. The following were used as exclusion criteria: age under 18 years, history of spinal injury and/or surgery, diseases of the nervous system, spinal and/or limb deformities and pregnant women were excluded from the study. The reason for this was the static changes in the musculoskeletal system during pregnancy and the resulting possible occurrence of spinal pain.

Measurement instrument

The research used a questionnaire consisting of three parts. The first part was the author’s “self-administered online questionnaire”. The second part is the Neck Disability Index (NDI) questionnaire Polish language version (Misterska, Jankowski & Glowacki, 2011a). While the third part is the Revised Oswestry Disability Index (ODI) Polish language version (Misterska, Jankowski & Glowacki, 2011b).

The author’s “self-administered online questionnaire” included questions on demographic data such as age, weight and height values. From these data, body mass index (BMI) was calculated. BMI was calculated as weight (kg) divided by height squared (m2) (Bryndal et al., 2023; Bryndal, Glowinski & Grochulska, 2022; Glowinski, Bryndal & Grochulska, 2021). Questions were also asked about the characteristics of the job, where they asked about the type of activities dominating the job, the number of working hours per month and the length of service. They were asked about the prevalence of current and past complaints of back pain, such as the location of the pain, the duration of the pain, the continuity of the symptoms, the presumed cause or causes and the positions that aggravate the pain. Back pain was defined as continuous or intermittent pain lasting 3 or more days, and respondents were asked to mark the appropriate response indicating the location of the pain. The physical activity performed was also asked about physical activity as broadly defined as physical recreation (Bryndal et al., 2023; Bryndal, Glowinski & Grochulska, 2022; Glowinski, Bryndal & Grochulska, 2021).

In those who experienced pain, the intensity of the pain was determined using the Visual Analogue Scale (VAS). The VAS scale took the form of a ten-centimetre ruler on which the respondent marked the severity of pain on a scale from 0, which was defined as no pain at all, to 10, which was defined as the most severe pain imaginable (Bryndal et al., 2023; Bryndal, Glowinski & Grochulska, 2022; Glowinski, Bryndal & Grochulska, 2021).

The Neck Disability Index (NDI) Polish language version questionnaire was used to determine the rate of cervical disability due to NP (Misterska, Jankowski & Glowacki, 2011a). It consists of 10 questions on pain intensity, grooming, lifting objects, reading, headaches, ability to focus, working, driving, sleeping, resting.

The Oswestry Low Back Pain Disability Scale (ODI) Polish language version (Misterska, Jankowski & Glowacki, 2011b) questionnaire was used to determine the disability rate due to LBP. The authors have permission to use this instrument from the copyright holders. It consists of 10 questions on pain intensity, grooming, lifting, walking, sitting, standing, sleeping, sex life, social life, travelling. On the NDI and ODI scales, each question has six possible answers rated on a point scale from 0 to 5. The final score separately for each questionnaire is presented on a point scale from 0 to 50 or a percentage from 0 to 100%. The score is classified into an appropriate point or percentage range that determines the level of disability: 0–4 pts. (0–8%) no disability, 5–14 points. (10–28%) mild disability, 15–24 points (30–48%) moderate disability, 25–34 points (50–64%) severe disability, 35–50 points (70–100%) extreme suffering and disability (Misterska, Jankowski & Glowacki, 2011a; Misterska, Jankowski & Glowacki, 2011b).

Test procedure

The author’s NDI and ODI “self-administered online questionnaire” was distributed electronically to respondents to the email addresses of medical facilities and departments employing midwives (Misterska, Jankowski & Glowacki, 2011a; Misterska, Jankowski & Glowacki, 2011b). The questionnaire was sent electronically to medical facilities located in northern Poland in the Pomeranian Voivodeship that employ midwives, based on the list of the Pomeranian Voivodeship Branch of the National Health Fund. In the Pomeranian Voivodeship in 2023, the occupational activity rate was 63.3% (1,303 midwives) out of the registered 2,058 midwives. Nationwide in Poland, the occupational activity rate was 70% (29,203 midwives) out of the registered 41,719 midwives (MedMedia, 2023). At the beginning of the questionnaire, an information form about the study and informed consent was presented. We informed the respondent of the anonymity of the survey and that the results of the survey would be used in scientific research and suggested that the responses should be honest. 241 people agreed to take part in the study, of whom eight did not meet the inclusion criteria and the remaining 25 did not complete the questionnaire correctly.

Statistical analysis

All statistical analyses were performed using the STATISTICA software, version 13.3 (2020), from StatSoft Inc. (Palo Alto, CA, USA). Descriptive statistics for quantitative variables included the arithmetic mean, standard deviation, median, minimum and maximum values (range), and 95% confidence intervals (CI) (Glowinski, Bryndal & Grochulska, 2021). The Shapiro–Wilk W test, Lilliefors test, Kolmogorov–Smirnov test, and Jarque–Bera test were applied to assess whether a quantitative variable followed a normal distribution. The Levene (Brown-Forsythe) test was employed to examine the homogeneity of variances. For comparing differences between two groups (independent samples), the Student’s t-test was used when variances were equal, and the Mann–Whitney U test was used when the assumptions for the t-test were not met. The Kruskal–Wallis test was applied to evaluate differences within the same variable across different groups when the normality assumption was violated, followed by a post hoc test if a significant result was found. Correlation analysis used Pearson’s correlation coefficients to explore the strength and direction of relationships between variables. Before investigating these relationships, scatter plots were generated to assess the potential presence of outliers visually. A significance level of p = 0.05 was used for all tests, with significant results highlighted in bold in the tables.

Job characteristics of the study group of midwives

Length of service in the study group ranged from 1 to 45 years of service (mean (SD) 24.4 (11.6)). The number of working hours per month ranged from 48 to 280 h (mean (SD) 167.6 (26.6)). The working system as single shift was declared by 34 midwives (16.3%), double shift by 146 midwives (70.2%), 24-hour on-call by 3 midwives (1.4%) and mixed system by 25 midwives (12.0%).

Characteristics of pain in the study group of midwives

Back pain during their working lives was declared by 203 midwives (97.3%). In the back pain group, 116 women (57.1%) declared NP of which 68 (58.6%) had pain centrally, 23 (19.8%) had pain with radiation to one upper limb, while 25 (21.6%) had pain with radiation to both upper limbs. In the group of people with back pain, 41 (19.7%) declared pain centrally in the thoracic part of the spine. In the group of midwives with back pain, as many as 192 (94.6%) declared LBP, of whom 96 (50.0%) had pain centrally, 87 (45.3%) had pain radiating to one lower limb, while nine (4.7%) had pain radiating to both lower limbs. Respondents in the question that dealt with the occurrence of pain at a particular level of the spine were given the opportunity to select several answers, which resulted in the number of respondents in a given group and the percentage distribution may be more than 100%.

The intensity of pain on the VAS scale was rated from 2 to 10 (mean (SD) 4.65 (1.53)). Respondents rated their pain on the VAS scale most frequently as 3 (mild/moderate) 22 people (10.68%), 4 (moderate) 81 people (39.32%), 5 (moderate/strong) 42 people (20.39%) and 6 (strong) 29 people (14.08%).

The time of the first incident of back pain was described by 10 people (4.85%) as one year ago, 44 (21.36%) as 2–3 years ago, 55 (26.70%) as 4–6 years ago, 18 (8.74%) as 7–9 years ago, 79 (38.35%) as more than 10 years ago, while 2 people (0.96%) did not answer this question. The number of spinal pain episodes in the past was defined as zero by seven people (3.37%), between 1–5 was defined by 80 people (38.46%), between 6–10 was defined by 33 people (15.87%) while 11 or more episodes was defined by 88 people (42.31%).

The nature of the pain and its frequency in the study group was rated by respondents as constant pain with 47 people (22.82%). Pain that comes and goes once a day–35 (16.99%) once a week–51 (24.96%), once a month–28 (13.59%), once a year–9 (4.37%). Pain that appeared and subsided several times in their working lives was declared by 33 midwives (16.02%), while one that appeared and subsided only once in their working lives was declared by three midwives (1.46%).

In the group of midwives with back pain, 69 women (34.0%) declared the use of sick leave due to these complaints, while the use of painkillers for the same reason was declared by 144 women (70.9%). In the question on the use of treatment for back pain other than painkillers, 33 people (16.02%) declared no treatment, 23 people (11.17%) used medical advice, 69 people (33.50%) used rehabilitation/physiotherapy treatment privately, while 60 people (29.13%) used insurance, and other treatments were declared by 21 people (10.19%).

Respondents were also asked whether they had any mobility limitations due to back pain 206 of the total sample answered. In response to this question, 47 people (22.82%) said they had no limitations, 133 (64.56%) had partial limitations, 22 (10.68%) had limitations that made it difficult to work and three people (1.46%) said limitations prevented them from functioning independently.

With regard to the maintenance of ergonomics at work, midwives were asked whether they use aids when performing physically demanding tasks, with 205 of the entire study group responding. One hundred women (48.54%) are assisted by a second person, zero (0.00%) are assisted by a hoist, 100 (48.54%) perform these activities alone, while five people (2.43%) use another method.

Of the 208 midwives participating in the survey, 206 responded to the question on identifying the activities that generate the occurrence of pain, 108 (52.43%) identified that after lifting a load, 128 (62.14%) that during bending, 78 (37.86%) during standing, 65 (31.55%) during sitting, 68 (33.01%) during trunk twisting, 21 (10.19%) during trunk hyperextension. Respondents could have given several answers to this question, which is why the total % is more than 100%.

Physical activity in the study group of midwives

The nature of the physical activity undertaken was determined in the study group, with 205 midwives responding to these questions. In defining the type of physical activity undertaken, 18 (8.74%) declared that they did not undertake physical activity, 83 (40.29%) described it as mild physical activity, 101 (49.03%) described it as moderate, medium physical activity, while three (1.46%) described it as intense physical activity. The duration of a single physical activity was described by 19 people (9.22%) as none, 87 people (42.23%) declared 10–30 min, 64 people (31.07%) declared 30–50 min, while 35 people (16.99%) declared 50 min or more. The frequency of physical activity per week was described by 40 people (19.42%) as one time or zero, 102 people (49.51%) described it as 2–3 times, 40 people (19.42%) described it as 4–5 times, while 17 (8.25%) described it as 6–7 times.

ODI and NDI results among midwives

In the entire study group, 116 women declared NP, while 206 midwives completed the NDI questionnaire. Among those surveyed, 192 women declared LBP, but 206 midwives completed the ODI questionnaire. Table 1 presents the characteristics of participants with LBP who completed the ODI and NDI questionnaires (n = 206 for both scales). The mean ODI score was 7.62 (SD = 4.99, 95% CI [6.94–8.31], median = 7, range 0–25), while the mean NDI score was 7.74 (SD = 6.11, 95% CI [6.90–8.58], median = 7, range 0–23). Most participants reported minimal disability, with 60 (61.65%) in the “no disability” category (0–4 points) on the ODI and 66 (32.04%) on the NDI. Light disability (5–14 points) was the most prevalent category for both scales, accounting for 127 (61.65%) and 109 (52.91%) participants, respectively. Mild disability (15–24 points) affected 17 (8.25%) on the ODI and 31 (15.05%) on the NDI, while severe disability (25–34 points) was rare (ODI: 2 participants, 0.97%; NDI: 0 participants). No participants reported extreme suffering or disability (35–50 points) on either scale. This data highlights the generally low disability levels in this cohort, with light and mild disability being the most common.

Level of significance for selected relationships

In a study group of midwives reporting back pain during their professional careers, the intensity of pain, as measured by the VAS scale, showed a statistically significant correlation with both age (R = 0.2476) and work experience (R = 0.2758). The results indicated that higher age and longer work experience were associated with higher pain scores. Each data point represents an individual, and the trend line illustrates a slight increase in VAS scores with age. Figure 1B similarly shows a weak positive correlation (R = 0.2758) between years of service and VAS scores, suggesting a slightly stronger association compared to age. Both figures underscore the limited strength of these relationships. Additionally, no statistically significant association was found between BMI and VAS scores (R = 0.0011).

Scatter plot Fig. 2A shows the relationship between age and NDI scores, with a weak positive correlation (R = 0.1731). Scatter plot Fig. 2B illustrates the relationship between years of service and NDI scores, showing a weak positive correlation (R = 0.1987). Scatter plot Fig. 2C presents the relationship between body mass index (BMI) and NDI scores, with a weak positive correlation (R = 0.1685). The higher the age, BMI, and work experience, the higher the NDI score.

Figures 3A–3C presents a correlation for lumbar back pain (ODI). For example, Fig. 3A shows a moderate positive correlation (R = 0.3338) between age and ODI scores. Figure 3B illustrates a stronger positive correlation (R = 0.4074) between years of service and ODI scores. Figure 3C presents a scatter plot showing a weak positive correlation (R = 0.2718) between BMI and ODI scores. Together, the plots highlight different strengths of positive associations between ODI scores and the analyzed variables.

Table 2 presents the correlation analysis between various variables and three health-related indices: VAS, NDI and ODI. Statistically significant correlations (p < 0.05) are highlighted in red. There is a significant moderate positive correlation between age and both VAS (0.2476) and ODI (0.3338), as well as a weak positive correlation between age and NDI (0.1731). For BMI, there is a minimal and non-significant correlation with VAS (0.0011), but a weak positive correlation with NDI (0.1685) and a moderate positive correlation with ODI (0.2718), both of which are significant. This suggests that age, BMI, and length of service are significantly positively correlated with VAS, NDI, and ODI. On the other hand, no significant correlations are observed between the average number of working hours per month and any of the indices. The strongest correlation in the table is between the length of service and ODI (0.4074), indicating a notable association.

Table 3 presents the significance levels for selected relationships between work-related factors, physical activity, and three health-related indices: VAS, NDI, and ODI. The variables analyzed include the system of work, sick leave, use of painkillers, type and duration of physical activity, and frequency of physical activity. Statistically significant results (p < 0.05) are highlighted, with specific statistical tests indicated (Kruskal-Wallis or UMW). Key findings include significant differences for sick leave and painkiller use across all indices (VAS, NDI, and ODI), with higher scores observed among those who used painkillers or had taken sick leave. The type of physical activity performed also showed a significant relationship with VAS (p = 0.0054), while physical activity frequency correlated significantly with NDI (p = 0.0132). Additionally, physical activity time exhibited significant differences for NDI and ODI, particularly for longer durations of activity. These results emphasize the impact of work patterns, pain management strategies, and physical activity on the indices of pain and disability.

Figure 4 illustrates the relationship between VAS scores and three variables: use of sick leave, use of painkillers, and type of physical activity. Panel A shows that individuals who took sick leave reported significantly higher VAS scores compared to those who did not (p < 0.0001). Similarly, Panel B reveals that those who used painkillers had higher VAS scores than those who did not (p < 0.0001). In Panel C, the type of physical activity significantly influenced VAS scores (p = 0.0054), with mild activity associated with lower scores compared to moderate, intense, or no physical activity. These results, visualized through box plots, highlight significant differences across groups, suggesting that VAS scores, likely reflecting pain or discomfort, are affected by these factors.

Figures 5A–5D underscore significant associations between NDI scores and factors such as sick leave, painkiller usage, activity time, and activity frequency. Figure 5A presents a box plot comparing NDI scores between individuals who took sick leave and those who did not. The group utilizing sick leave demonstrated significantly higher median NDI scores (p < 0.0001), highlighting a strong association between elevated NDI scores and the likelihood of taking sick leave. Figure 5B illustrates the distribution of NDI scores among individuals who use painkillers versus those who do not. Participants using painkillers exhibited significantly higher NDI scores (p = 0.0009), suggesting a clear link between painkiller usage and increased disability. Figure 5C examines the relationship between activity time and NDI scores, revealing significant variation across different activity time categories (p = 0.0323). Generally, longer activity durations were associated with higher NDI scores. Figure 5D explores the relationship between activity frequency and NDI scores, showing significant differences across frequency categories (p = 0.0132). Notably, individuals engaging in 30 to 50 min of weekly activity had the lowest NDI scores, while those exercising only 10 to 30 min per week reported the highest scores. Frequency also played a crucial role: participants exercising 4–5 times per week recorded lower NDI scores than those exercising just once weekly. However, individuals who reported exercising 6–7 times weekly displayed NDI scores similar to those exercising only once a week. This suggests that excessive exercise intensity may also contribute to heightened cervical spine pain.

Figure 6A presents a box plot comparing ODI scores between midwives who used sick leave and those who did not. Higher median ODI scores were observed in the group that used sick leave (p < 0.0001), indicating that individuals with higher ODI scores are more likely to take sick leave. Figure 6B illustrates ODI scores for individuals who use painkillers compared to those who do not. Similar to the sick leave group, individuals using painkillers had significantly higher ODI scores (p < 0.0001). Figure 6C shows a box plot depicting the relationship between activity time and ODI scores. ODI scores varied significantly across the activity time categories, with longer activity times generally associated with higher ODI scores (p < 0.0001). These plots highlight significant differences in ODI scores based on the examined factors. Type of physical activity did not affect ODI (p = 0.0865). In summary, midwives who claimed to be physically active for more than 30 min obtained higher ODI values that were statistically significant than those who exercised between 10 and 30 min per week.