The Prevalence of low back pain in Africa: a systematic review

The health of Africans is of global concern, as improvement in health outcomes observed in most Western countries over the past few decades has not been achieved in Africa [1]. This has been attributed more recently to the negative impact of the HIV and AIDS epidemic, reflecting both the focus shift of health interventions, and funding directions in health research [1]. Africa accounts for about 14% of the world's population, and it is also the poorest continent, bearing about 40% of the global burden of disease [1, 2]. A positive causal relationship between income and health is well recognized internationally, in which a higher income promotes good health by the economical ability to access clean water and sanitation, good nutrition and good quality health services [2]. Lack of access to these resources consequently predisposes communities to a greater prevalence of disease and disability [3]. Socioeconomic constraints in Africa therefore underpin the higher prevalence of many diseases and disabilities [1, 2].

The global prevalence of general disability is highest in sub-Saharan Africa [4]. The etiology of disability is multi-factorial and varies between different parts of the world [4]. The most apparent difference in disability prevalence is between the developed and developing worlds [5], with the most frequent cause of disability being musculoskeletal disorders [6]. The difference in disability prevalence between the developed and developing worlds is one example of global differences in health. Musculoskeletal disorders accounts for about 4.3% of disability life adjusted years (years living with disability) in the developed world, whilst it is reported as accounting for approximately 1% in the developing world [1]. Pain and loss of function associated with musculoskeletal conditions primarily leads to disability [7]. The four major musculoskeletal conditions leading to disability include osteoarthritis, rheumatoid arthritis, osteoporosis and low back pain (LBP) [7].

LBP is the most prevalent musculoskeletal condition and the most common cause of disability in developed nations [7]. The lifetime prevalence of LBP (at least one episode of LBP in a lifetime) in developed countries is reported to be up to 85% [8]. LBP results in significant levels of disability, producing significant restrictions on usual activity and participation, such as an inability to work [9]. Furthermore, the economic, societal and public health effects of LBP appear to be increasing. LBP incurs billions of dollars in medical expenditures each year [10] and this economic burden is of particular concern in poorer nations such as Africa, where the already restricted health care funds are directed toward epidemics such as HIV and AIDS [8].

A review of research publications on LBP suggests that most research has been conducted in the developed world, where little racial heterogeneity exists [11]. Racial, economic and social homogeneity is not a feature of Africa, a developing country. It is logical, therefore, to argue that genetic diversity, and differences in social structure and economics between the developed and developing nations, may underlie reported differences in the prevalence of LBP [6]. Other African-specific factors such as the HIV and AIDS epidemic, types of work tasks and poor nutrition may also influence LBP prevalence among Africans [1].

The literature on the epidemiology of LBP is accumulating, but for the most part, studies are restricted to high-income countries, therefore little is known about the epidemiology of LBP in the rest of the world [12]. In developed countries such as the United States of America (USA) and Australia, LBP prevalence ranges from 26.4% to 79.2% [13, 14]. There appears to be a general (albeit anecdotal) assumption that LBP prevalence in Africa is lower than that reported in the developed nations [15‐17]. A systematic review into the global prevalence of LBP by Walker in 2000, identified that of the 56 included studies, only 8% were conducted in developing countries, with only one study conducted in Africa [8]. The lack of information on the prevalence of LBP in developing countries is therefore a significant shortcoming [8, 17], particularly as it is predicted that the greatest increases in LBP prevalence in the next decade will be in developing nations [6]. Understanding prevalence and causality of LBP in developing nations such as Africa may assist understanding of global LBP causes and management [8, 17], and will determine whether the factors differ in socio-cultural characteristics [17].

To our knowledge, no systematic review reporting on the prevalence of LBP on the African continent exists. The aim of this review was therefore to systematically appraise peer-reviewed published disease prevalence studies conducted on the African continent, in order to ascertain whether LBP is of concern among Africans, as it is globally. This review considered the methodological quality of the relevant literature in order to identify opportunities for improvement in research practices, as well as to establish a way forward for high quality research in this area in Africa.

This review was part of a larger, more comprehensive study which investigated the prevalence of cervical, thoracic and lumbar spine pain (or LBP) in Africa. The LBP epidemiological findings are reported in this paper.

The specific objectives of this element of the review were:

1. To determine the prevalence of LBP on the African continent.

2. To describe the primary risk factors of LBP among Africans living on the African continent.

3. To critically appraise the methodological quality of the prevalence studies with a view to identifying opportunities to improve future research quality.

The following terms and definitions were applied to this review:

The comprehensive search for published epidemiological research into cervical, thoracic and lumbar spine pain (or LBP) conducted on the African continent yielded 3627 hits, of which 3143 articles were excluded as the title and/or the country of publication did not conform to this review's objectives. As the current review focused solely on the prevalence of LBP in Africa, studies which reported on cervical and thoracic spine pain were not included. Two additional relevant studies were included via the PEARLing method. Consequently, 27 eligible studies were included in this review [11, 15, 16, 19‐42]. The database search method and results are depicted in figure 1.

This is the first known systematic review to report on the findings of LBP prevalence and LBP risk factors among African populations. A global review published in 2000 suggested that only one African study was available for inclusion [8]. This current review reports a much larger group of relevant African studies (most published since 2000), of which 67% were methodologically sound. This review indicates that there is little difference in the prevalence of LBP among Africans compared with the prevalence of LBP in developed countries. The earliest publication in this review was written in 1990, which may indicate that LBP prevalence may be a relatively recent and emerging problem in Africa [19]. However this may also be an indication that publishable LBP research has only received resource support since the early 1990s, reflecting constraints on health research resources available on the African continent for orthopaedic research, as a result of urgent research into other health threats such as HIV/AIDS.

The most common population group studied was "workers". This finding is plausible given that there is a lack of legislation to support workers suffering from LBP to ensure that they receive optimal rehabilitation and support. In contrast, in western societies, legislation to promote spinal health protects workers from lumbar spine injury or pain is in place and is monitored by government bodies [43]. The lack of best practice rehabilitation methods for LBP which could prevent chronic pain and disability is evident in the reports of the most common treatment methods reported in the African research to treat LBP. Despite the increasing scientific evidence from meta-analyses that active rehabilitation involving exercise is most effective in reducing disability and LBP recurrence [44, 45], the most common forms of management identified in this review were rest and analgesics. Well designed prevalence studies into African LBP, coupled with intervention studies to test the effectiveness of high quality interventions should be undertaken to inform and transform labor legislation policies to ensure better support for workers suffering from LBP.

'School scholars' were the second most common group studied by African researchers. This is viewed as a positive step, particularly with respect to setting the scene for primary prevention of LBP. The results of this review indicate that there is reason for concern regarding LBP prevalence in adolescents. Of further concern is that a "history of LBP" as reported in many western societies as a causal agent of LBP, may also be an important predictor of LBP among Africans. This implies that much LBP experienced by young people may manifest into chronic LBP in adulthood. Chronic LBP is costly to manage due to recurrent and debilitating nature of the condition. The findings of this review indicate that primary prevention should be considered an African priority due to the already constrained economic resources for overall health care [3, 5, 8]. Another factor that may be increasing the prevalence of LBP among young African people is the widespread introduction of information technology systems in African schools. For instance, in the Western Cape of South Africa, all or most schools will probably be equipped with computer laboratories by the year 2012 for curriculum delivery in an attempt to compensate for the increasing shortage of school educators. While the use of technology may be best practice for educating young people, it also introduces the likelihood of young people developing poor postural habits unless they are specifically instructed otherwise. The school setting may therefore be appropriate to teach young people good spinal health habits, and future research should incorporate spinal health promotion strategies for schools in Africa.

The mean LBP point prevalence among the African adolescents was 12% and among the African adults 32% (range 10% to 59%). This finding negates any assumptions that LBP point prevalence is lower in the developing world than developed societies, as the range of LBP point prevalence among western societies is also reported to range between 12% and 33% [8, 37]. This revelation supports the findings of the global burden of disease studies which predict that the greatest increases in LBP prevalence will be in developing nations [6]. Unfortunately, the data obtained from the studies included in this review is insufficient to ascertain the trend of LBP over more than 2 decades, as the earliest methodologically acceptable study reporting point prevalence was published in 1993 [29]. However, with over 80% of the included studies published after the year 2000, there will be the capacity in a few years time to predict African LBP prevalence trends with some certainty.

The one-year LBP prevalence among Africans ranged from 14% to 72%. The one-year prevalence among Western societies is reported to be between 20% and 62% [8]. Therefore it appears that the one-year prevalence estimated among Africans correlates with the one-year LBP prevalence in Western societies. Similarly, comparable findings were observed for lifetime prevalence estimates as African lifetime prevalence ranged from 28% to 74%, whilst lifetime prevalence in Western societies ranged from 30% to 80% [37]. Advances in technology and the mechanization of industries in African countries may therefore be reflected in the high one-year and lifetime prevalence of LBP among Africans, reported in the past decade of research. However, there is insufficient data on rural populations as only three [25, 26, 41] of the 18 methodological acceptable studies provided data exclusively on rural populations. The prevalence reported in these studies is comparable to reported urban population prevalence, and may reflect that the considerable physical activities required for rural (farming) activities may be a risk factor for LBP [25, 26, 41]. The study by Omokhodion (2004) illustrates that farming activities increase the odds of suffering LBP by four, compared with individuals not exposed to farming activities [16]. These findings related to one-year and lifetime prevalence, and further illustrates that LBP among all Africans is of concern. Further research into the most effective strategies to manage and prevent LBP is warranted.

Nine of the studies were excluded from data analysis due to the fact that they did not score above 70% methodologically. The most common shortcomings were a clear definition of LBP, lack of adequate representation of the population, lack of detail on the instrument used, and lack of using a reliable and valid questionnaire to collect data (Tables 1 and 6). These methodological shortcomings have ramifications into the validity of the study findings. For instance if a questionnaire is not culturally appropriate for a specific African population, it could mean that inappropriate or incomplete questions were asked pertaining to potential risk factors, or that respondents did not answer some questions as they were considered culturally insensitive or inappropriate. The mean response rate to the African studies included in this review was 88%, which correlates with the mean response rate of 81% reported in the systematic review by Walker [8]. The reason for poor response rates in six [15, 30‐33, 42] of the African studies was often cited as incomplete questionnaires, and this may be because the questionnaire content and language was not culturally acceptable. One critical area to be addressed by African researchers is to ensure that data collection tools are valid for specific target populations, and are reliably answered.

The findings of this review indicate that the prevalence of LBP among Africans may be comparable to that reported in research undertaken in developed nations. Therefore further research into the identification, prevention and best practice management of LBP is also necessary in African countries. Furthermore, there is a clear mandate for African researchers to improve the methodological quality of their LBP epidemiological studies, considering the reliability and validity of measurement instruments, and agreeing on a standard definition of the condition. Possible limitations to this study could be that certain African journals were inaccessible on electronic databases, as they were published locally, were only available in the specific African country and not obtainable in South Africa. There was difficulty contacting the researchers and libraries in these countries.

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