Low back pain is one of the most common health problems and creates a substantial personal, community, and financial burden globally (1–4). As part of estimating the global burden of low back pain, with low back pain defined as “activity-limiting low back pain (+/− pain referred into 1 or both lower limbs) that lasts for at least 1 day” (5), country-specific prevalence data were required.
The most recent global review of the prevalence of low back pain in the adult general population was published in 2000 and showed point prevalence of 12–33% and 1-year prevalence of 22–65% (6). Since then, 2 additional global reviews have been conducted, one of which focused on the elderly (2) and the other on adolescents (7). A key finding from these reviews was the extent of methodologic variation between studies, especially regarding the case definition and prevalence period used, and the nature and extent of measures taken to minimize bias (2, 6–10).
Although these previous reviews made a major contribution to our understanding of low back pain, a large number of prevalence studies have been published subsequently. The specific aim of the current study was to perform an up-to-date systematic review of the global prevalence of low back pain for informing the Global Burden of Disease (GBD) study, and in doing so, to examine the influence that case definition, prevalence period, and other variables have on prevalence.
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- AUTHOR CONTRIBUTIONS
- Supporting Information
Our updated systematic review of the global prevalence of low back pain showed that low back pain is a major problem throughout the world and is most prevalent among females and persons ages 40–80 years. After adjusting for methodologic variation, the mean ± SD point prevalence of activity-limiting low back pain lasting more than 1 day was estimated to be 11.9 ± 2.0%, and the 1-month prevalence was estimated to be 23.2 ± 2.9%. Due to significant methodologic heterogeneity between the included studies, single summary measures, such as mean prevalence, should be interpreted with caution.
This systematic review of the global prevalence of low back pain is the first to assess the risk of bias in the included studies and is the first study in which a sensitivity analysis was performed to assess the impact of including estimates with a high risk of bias (11, 12, 28). The sensitivity analysis showed that the overall mean prevalence would have been significantly higher if estimates with a high risk of bias had been excluded. In addition, 5 of the 10 individual items on the risk of bias tool had a significant influence on prevalence. These findings provide empirical data about the direction of the bias and its potential effect.
We observed a substantial increase in the number of studies of low back pain prevalence since the last comparable review (6). Similar to other reviews, we observed considerable methodologic variation between studies, which particularly related to the prevalence period and case definition (2, 6, 9, 29). A standardized definition of low back pain will assist future reviews, enable greater comparisons between countries, and ultimately lead to a far-improved understanding of low back pain.
Dionne et al (30) recommended using the following questions in prevalence studies of low back pain: 1) In the past 4 weeks, have you had pain in your low back? and 2) If yes, was this pain bad enough to limit your usual activities or change your daily routine for more than one day? Those investigators emphasized the importance of describing the specific anatomic area and, when possible, using a diagram of the body with the low back area shaded. The area they recommend for the low back is “the posterior aspect of the body from the lower margin of the twelfth ribs to the lower gluteal folds” (30). Given that low back pain is quite common, point prevalence estimates are also useful to capture and are easily interpreted by policy-makers.
In addition, a detailed description of the study population aids the validity of comparisons between populations. Factors of interest include age, sex, history of low back pain, occupation, job satisfaction, educational status, stress, anxiety, depression, social support in the workplace, body mass index, and family history of low back pain (31).
Consistent with other research, we observed a higher mean and median prevalence of low back pain among females compared with males (9, 32). Possible explanations for this difference include 1) pain related to osteoporosis (33), menstruation (34–36), or pregnancy (37–39), 2) individual or societal influences resulting in sex differences in the likelihood of reporting somatic symptoms (32, 40, 41), and 3) the divergent growth patterns between the sexes during adolescence, which may influence pain in this period (7).
We observed that the prevalence of low back pain was high during adolescence, which concurs with a previous review showing that the prevalence of low back pain increases throughout adolescence, and this peak often appears earlier in girls than in boys, possibly as a result of an earlier onset of puberty (7). In our review, the prevalence of low back pain was highest during middle age, which represents some of the most productive years of a person's working life. This results in a major economic impact for many individuals, families, businesses, and governments (42–44).
A curvilinear distribution of the prevalence of low back pain over age was also reported in a review by Dionne et al (2). Those investigators demonstrated that this was apparent for all low back pain; however, when they restricted their analysis to more severe forms of low back pain, they observed that the prevalence kept increasing in the older age groups. Consistent with these findings, there is some evidence that older individuals have a greater threshold for lower levels of pain but a reduced tolerance to more severe pain (45).
Dionne et al (2) suggested that many factors could explain the decrease in the prevalence of less severe low back pain that occurs with aging, including cognitive impairment, depression, decreased pain perception, and increased tolerance to pain. In addition, surveys often exclude persons living in institutions such as nursing homes (9), and these individuals may have a higher prevalence of low back pain compared with older persons living in the community.
Despite an increase in the amount of data since earlier reviews (6, 10), there continues to be a paucity of information on low back pain in countries with low-income and middle-income economies. Our data are consistent with a previous review showing that low back pain was less prevalent in countries with low-income and middle-income economies compared with countries with high-income economies (10). The lower prevalence of low back pain in developing countries has been speculated to be attributable to higher levels of exercise, shorter height, higher pain thresholds, and less access to industrial insurance compared with countries with high-income economies (10).
Methodologic issues are also likely to explain some of this difference, including survey planning methods and differing case definitions and sample population age and sex structures. Related to this, researchers from countries with low-income and middle-income economies may, in some cases, experience greater barriers in trying to publish studies. For example, the majority of peer-reviewed journals accept submissions only in English. Moreover, difficulties in constructing accurate sampling frames and accessing remote regions and villages can greatly add to the challenge of publishing academically rigorous studies.
The mean lifetime prevalence of low back pain (38.9%) was much lower than expected and was particularly influenced by low rates from studies conducted in China (46–48), Nepal (49), Cuba (50), and Pakistan (51). The low prevalence of low back pain observed in these countries with low-income and middle-income economies may have several influences, some of which were discussed earlier. In addition, chronic low back pain may make up a larger proportion of all low back pain in these countries, making the ratio of lifetime prevalence to other prevalence periods lower in these countries compared with countries with high-income economies. Although no data support this, a study in Tibet showed a relatively low ratio of 1-year–to–point prevalence (42%:34%), suggesting that a high proportion cases of low back pain are chronic in nature (52). The relatively low lifetime prevalence observed in these studies may also be attributable to selection, measurement, and recall bias.
Similar to most systematic reviews, our study is likely to be subject to publication bias that may have inflated the prevalence estimates of low back pain (53). We attempted to limit the potential for publication bias by conducting an extensive search for potentially relevant studies and placing a specific focus on capturing information from countries with low-income or middle-income economies. In addition, we carefully examined the risk of bias for each included estimate.
Based on the results of this systematic review, low back pain continues to be a very common problem globally. With aging populations, the absolute number of people with low back pain is likely to increase substantially over the coming decades. Further research is needed to identify risk factors and culturally appropriate interventions to prevent and treat low back pain. Researchers are encouraged to adopt recent recommendations on defining low back pain in epidemiologic studies to assist future reviews, enable comparisons between countries, and improve our understanding of low back pain. Furthermore, the tool for assessing the potential risk of bias of included estimates could be used to improve the design of future epidemiologic studies.
- Top of page
- AUTHOR CONTRIBUTIONS
- Supporting Information
All authors were involved in drafting the article or revising it critically for important intellectual content, and all authors approved the final version to be published. Dr. Hoy had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study conception and design. Hoy, Bain, Williams, March, Brooks, Blyth, Woolf, Vos, Buchbinder.
Acquisition of data. Hoy, March, Blyth.
Analysis and interpretation of data. Hoy, Bain, Williams, March, Brooks, Blyth, Woolf, Vos, Buchbinder.