The findings of our study suggest that the mean prevalence of low back pain, thoracic spine pain and neck pain in our study population from Russia was 54.0, 23.6 and 29.1%, respectively. A higher prevalence of lower back/neck/thoracic spine pain was associated with female gender, younger age and a variety of parameters including higher body mass index, lower frequency of vigorous activities during leisure time, more time spent sitting and reclining, higher prevalence of a history of cardiovascular disease, falls, bone fractures, unconsciousness, osteoarthritis, iron-deficiency anemia and thyroid disorder, lower vegetable intake, and a higher anxiety score.
The findings obtained in our study agree with observations made in previous investigations on other ethnic groups. The lifetime prevalence of low back pain was 54% in our study population of individuals aged 40+ years, which was higher than the prevalence reported in previous investigations of other study populations in other countries [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16]. Urwin and colleagues estimated the frequency of musculoskeletal pain in different anatomical sites in an adult population in general medical practices in the Greater Manchester region in the UK [6]. After an adjustment was made for social deprivation, the most common site of pain was the back (prevalence: 23% (95% CI: 21, 25)) followed by the knee (19% (95% CI: 18, 21)) and shoulder (16% (95% CI: 14, 17)). Johansson and colleagues performed a systematic literature review to assess the frequency of mid-back pain (or thoracic spine pain) [3]. Summarizing seven studies, they reported that the 3-month and 2-year incidence rates of mid-back pain in children and adolescents was 4 and 50%, respectively. In adults, the 1-month incidence rate was less than 1%. After performing a literature review, Meucci and coworkers estimated the global prevalence of chronic low back pain [14]. The prevalence of chronic low back pain was 4.2% in individuals aged between 24 and 39 and 19.6% in those aged between 20 years and 59 years. The authors also reported that chronic low back pain prevalence increased linearly from the third decade of life until the age of 60 years and that it was more prevalent in women. Jackson and colleagues performed a meta-analysis of 119 studies in 28 low-to-medium income countries and reported an average prevalence of low back pain of 28% (95% CI: 16, 42) [15]. Garcia performed a systematic review of chronic nonspecific low back pain in Latin America and found a mean prevalence of chronic low back pain of 31.3% [13]. Some of the reasons for the discrepancies in the prevalence of low back pain between the various studies may be the differences between the study populations in terms of age, the time of the study, the inclusion of low-income countries versus high-income countries, the type of work, the differences in the definition of low back pain, and others. All studies reported a relatively high prevalence of low back pain in the general adult and elderly population and underscore the importance of low back pain as one of the leading level 3 causes of total DALYs in the Global Burden of Disease Study [1].
Additionally, the prevalence of neck pain was 29% in our study population, which was higher than the prevalence reported in other studies. Noormohammadpour and colleagues carried out a cross-sectional, population-based survey of 7889 Iranians aged 30 to 70 and found a prevalence of chronic neck pain and chronic low back pain of 15.3 and 27.2%, respectively [28]. In Noormohammadpour’s study, a higher prevalence of neck pain was associated with females, an older age, a body mass index ≥25 kg/m2, a lower level of education, passive smoking, a history of osteoporosis, and low or high physical activity levels. In a population-based study of 34,902 Danish twins with an age of 20–71 years by Leboeuf-Yde and associates, 12, 10, and 4% of the study participants reported having back pain, neck pain and thoracic pain, respectively, for at least 30 days in the previous year [29]. In the framework of the MONICA health survey, Guez and associates selected 4415 individuals with an age of 25–64 years and found a prevalence of chronic low back pain and chronic neck pain of 16 and 17%, respectively, with 51% of subjects having both back pain and neck pain [ 30]. Genebra and colleagues reported a prevalence of neck pain of 20.3% in 600 Brazilian individuals [31]. A higher prevalence of neck pain was correlated with the family status of being a widow and being separated, a low educational level or low income, and mostly sitting during work. All studies reproted that low back pain occurred more commonly than neck pain and that thoracic spine pain was the least common.
The prevalence of thoracic spine pain in our study population was 29.1% (95% CI: 27.9, 30.3). In a study by Fouquet N and coworkers on a group of 3710 workers (58% men) aged 20–59 years, the prevalence of thoracic spine pain in a week was 17% in females and 9% in males [32]. The prevalence was higher in lower-class, male, white-collar workers than in male workers in other occupational categories, and it was higher in upper-class, female, white-collar workers than in professional workers. After performing a cross-sectional study on 34,902 twin individuals with an age of 20 to 71 years, Leboeuf-Yde and colleagues found that pain with a duration of ≥30 days within the last year was reported by 4% of the study participants [29]. Females, compared to males, had a higher prevalence of thoracic spine pain. As in our study, the prevalence of thoracic spine pain increased with age up to an age of approximately 55 to 60 years and then decreased.
The reasons for discrepancies in the prevalences of low back pain, thoracic spine pain and neck pain between our studies and preceding investigations may include the differences in the study population, differences in the definition of the disorders, differences in the prevalences of risk factors for back pain, thoracic spine pain and neck pain, and others. All studies reported that the prevalence of low back pain was higher than the prevalence of the other two pain-associated disorders. In our study, the prevalence of thoracic spine pain was higher than the prevalence of neck pain, while in other studies, neck pain was more common. In many studies, as in our investigation, the prevalence of the pain disorders increased with age up to an age of approximately 60 years and then decreased (Figs. 1, 2, and 3). This nonlinear, inverted U-like shape of the association between pain prevalence and age may have been the reason for the discrepancy between some studies in which the prevalence of pain disorders increased or decreased with age.
A higher prevalence of low back pain, thoracic spine pain and neck pain were correlated with various factors, including females, a higher body mass index, a higher prevalence of a history of osteoarthritis, a higher anxiety score, a lower frequency of vigorous activities during leisure time and more time spent sitting or reclining during the last 7 days (Tables 2-5). Similar associations were reported in previous studies [33,34,35,36,37,38]. The associations between the prevalence of low back pain, thoracic spine pain and neck pain with age differed between the studies, probably due to the nonlinear relationship with an inverted U-shape curve (Figs. 1, 2, and 3) [34]. In contrast to our study, Shiri and colleagues found, a modest association (OR 1.33; 95% CI: 1.26–1.41) between both current and former frequencies of smoking and a higher prevalence of low back pain [39]. The association between a higher prevalence of the pain disorders and a higher body mass index might be caused by a larger load on the vertebral column due to a larger body weight [40]. The higher prevalence of pain disorders in females compared to males might have been associated with osteoporosis, which is generally more common in females than in males. Additionally, differences in the lifestyle between males and females might have played a role. The association with a higher anxiety score may have been a result of increases in insecurity and fear due to the pain. The correlation between a lower prevalence of back pain and a higher frequency of vigorous activities during leisure may be due to a more active lifestyle strengthening the muscles and reducing the risk for back pain. As a corollary, more time spent sitting or reclining was associated with a higher prevalence of pain-associated disorders. In a parallel manner, the correlation between a higher prevalence of back/neck/thoracic spine pain and a history of cardiovascular diseases may be explained by the association between a more sedentary lifestyle, back pain and cardiovascular problems. Also, the relationship between a higher prevalence of back/neck/thoracic spine pain and lower intake of vegetables may belong to the same circle of parameters on unhealthy lifestyle and back/neck/thoracic spine pain. The association between a higher prevalence of back/neck/thoracic spine pain and a higher prevalence of previous falls and bone fractures might have been bi-directional, with previous bone fractures potentially leading to back/neck/thoracic spine pain.
When the findings of our study are discussed, its limitations should be mentioned. First, although not a specific limitation of the present study, the definition of low back pain, thoracic spine pain and neck pain varied between previous investigations, so the results of the various studies cannot easily be compared. To cite an example, some of the previous studies used a definition of spinal pain with a duration of 30 days within the last year, while for our study, the intensity of pain had to be at least so strong that it was perceived as “uncomfortable or worse than uncomfortable”, that it reduced the quality of life, and that its duration had to be at least 1 hour per day. These variations in the definition of pain will have caused differences in the results when different studies are compared. Second, we attempted to grade the severity of pain by the information whether or not analgesic tablets were taken (Table 4). One may have to take into account that the use of analgesics depends on a variety of factors independently of the pain itself and which include the individual tolerability of pain and the access to the analgesic medication, to mention only a few. Third, one has to take into account in the discussion about the relationships between the prevalence of back/neck/thoracic spine pain and other parameters, that the study design did not allow any assessment about the causes of these relationships. In particular, one has to consider that these relationship could be going in either direction and many of the associations could be a result of the back/neck/thoracic spine pain rather than the preceding cause of the pain. The strengths of the study are that it is its first of its size and design for Russia and Eastern Europe, that it addressed not only back pain but a multitude of other parameters and diseases, which allowed the exploration of potentially hidden associations between back pain and these diseases, and that it recruited study participants from a rural region and an urban region.