Dor lombar em fumicultores do município de São Lourenço do Sul, RS

Abstract

Introduction Brazil is the world’s second largest tobacco producer and foremost tobacco exporter. The country’s southern region accounts for almost all national production and the state of Rio Grande do Sul (RS) alone is responsible for 50% of this production. Tobacco production involves labour intensive based on family farming. The production cycle occurs all year round and during the different production stages involves exposure to a variety of workloads, especially those involving physical exertion. This form of exposure at work frequently results in ergonomic problems such as acute and/or chronic low back pain and limitations/disabilities. Acute low back pain afects the majority of individuals at some time in their lives and is defined as pain ocurring between the twelfth rib and the inferior glutal line. Some 5 to 10% of cases last for more than three months, thus characterizing chronic low back pain, and result in high labour and social security costs because of time off work, in addition to the intense suffering of those affected by it. Although tobacco growing in southern Brazil employs hundreds of thousands of family farmers and the workloads of this activity represent risks of low back pain and limitations at work, studies assessing these outcomes in tobacco growers are rare. Objectives To write three scientific articles: the first evaluating the prevalence and factors associated with work limitations owing to low back pain among tobacco growers; the second evaluating the prevalence and factors associated with chronic low back pain (CLBP) among tobacco growers; and the third undertaking a systematic review to analyze information existing in the literature on CLBP prevalence in population-based studies. Methods The first two articles were based on information obtained from a cross-sectional study with a sample of 2469 tobacco growers aged eighteen or over in the municipality of São Lourenço do Sul, RS. Low back pain was determined by using an adapted version of the Nordic Questionnaire on musculoskeletal disorders. Limitations at work because of low back pain were determined by asking those who reported low back pain the following question: "During the last twelve months have you had to stop doing certain activities at work because of pain in the lower region of your back?" The third article (a systematic review) used rigorous selection criteria to find studies evaluating chronic low back pain prevalence. Results 2469 individuals were interviewed. 8.4% reported CLBP, 36.0% reported having had low back pain in the last month (LBPM) and 30.8% had acute low back pain. 6.2% had had limitations at work because of low back pain. There was 37.6% prevalence of these limitations among respondents with CLBP, whilst the prevalence of these limitations among those with LBPM and Acute LBP was 14.4% and 7.8%, respectively. The tasks that the respondents most stopped doing as a result of all these kinds of pain were: carrying tobacco leaves from one place to another, transplanting tobacco plants, stacking firewood and gathering lower leaves. Age was directly associated with LBPM limitations and risk was higher in older individuals (3.34 PR; 95%CI 1.73-6.44), whilst expenditure with Vehicle Tax (IPVA) was inversely associated. Having difficulty in paying debts (1.55 PR; 95%CI 1.06-2.25) and minor psychiatric orders (1.95 PR; 95%CI 1.40-2.72) were also factors associated with limitations at work because of LBPM. Risk factors associated with CLBP included rearing one or more species of animals (1.65 PR; 95%CI 1.14-2.38) and being older. Heavy physical exertion (2.00 PR; 95%CI1.43-2.79), working in awkward positions (1.36 PR; 95%CI 1.02-1.82), green tobacco sickness (1.63 PR; 95%CI 1.18-2.25), pesticide poisoning (2.37 PR; 95%CI 1.70- 3.32) and minor psychiatric disorders (2.55 PR; 95%CI 1.88-3.47) were also associated with CLBP. With regard to the systematic review of the literature, 28 population-based studies were selected, 13 of which defined chronic pain as being continuous pain lasting for three months or more. In the studies with response rates greater than 75%, age was the characteristic that most influenced CLBP prevalence, varying between 4.2% in studies with individuals aged 24-39 and 19.6% in those with individuals aged 20-59. CLBP prevalence varied between 3.9% and 10.2% in six out of eight studies with people aged ≥18/20/21. Conclusions High chronic low back pain prevalence was found and resulted in people having limitations at work, specifically in relation to tasks placing greater strain on the lumbar spine. Further studies are needed to provide more in-depth knowledge about the effects of acute and chronic low back pain in farm workers. Similarly, studies on CLBP need to be standardized, specifically in relation to its anatomical location and chronicity. Alternatives such as harvest mechanization need to be discussed by farm workers, representative organizations and researchers in order to ensure better protection of tobacco workers’ health. Similarly, health professionals providing care to farm workers need to be familiar with risk factors and limitations resulting from low back pain, in particular CLBP, so as to promote its prevention and avoid it becoming chronic. In addition, discussions about crop diversification and the meaning of grueling farm work aimed at producing a product which is a risk factor for countless diseases should take into account the vulnerability of these workers, as well as providing effective improvement in working conditions on farms.