Lower back pain and level of disability amongst construction workers

Introduction: Lower back pain is a symptom that significantly affects people’s lives, especially workers whose professional achievements can be limited by this pain. Objective: Estimate prevalence of lower back pain and describe the levels of disability amongst construction workers. Methods: 84 construction workers participated in this study. Each of them was given three questionnaires. The first questionnaire was aimed at identifying sociodemographic variables such as work and lifestyle habits. The second questionnaire was created by Monnerat and Pereira to measure the intensity of lower back pain. The last questionnaire was created by Roland-Morris to measure functional incapacity. The SPSS 18.0 program was used for data analysis. Lower back pain was described with the Mann Whitney U test using the variables of both labor and time. Furthermore, a correlation between lower back pain intensity and functional incapacity was found by Spearman. Results: A higher prevalence of lower back pain was found (71.4%) amongst the construction workers especially during laborious activity. Time worked did not affect the prevalence of lower back pain nor did it lead to functional incapacity in workers. Conclusion: Based on all observed data, it was concluded that strenuous labor activity amongst the populace drove lower back pain prevalence.


Introduction
A vast number of individuals in the world are affected by spinal pain (1).Furthermore, the most prevalent form of spinal pain occurs in the lower back (2).
Lower back pain is a debilitating symptom that can potentially limit a person's quality of life, especially workers whose professional achievements can be limited by this pain (3).
Lower back pain stemming from strenuous activity is usually caused by biomechanical tension due to excessive anterior lexions and worsens with heavier weight.Thus, poor or static posture, vibrations, repetitive movements for long durations all contribute to lower back pain (4).The construction industry is a prime example of a career in which lower back pain induced from labor is common.The labor is intensive and demanding, often requiring the lifting of heavy weight which can cause excessive stress and pressure on the vertebrae and intervertebral discs (5).
Construction workers show higher prevalence of lower back pain due to the exhausting nature of their labor.It is important to emphasize that bad work conditions and low education rates also contribute to this prevalence (6).
People who felt this type of pain presented higher fears of it worsening; therefore they avoided making drastic movements.In addition, their work conditions predispose them to functional incapacity causing a negative impact on their quality of life (7).
Beside the impact on their quality of life, this functional incapacity causes numerous labor disorders, which leads them to withdraw from work more often (8).It is the most common labor injury that INSS deals with and it represents an important health problem in Brazil (9).This functional incapacity affects both the emotional and physiologic tools of the individuals.This can contribute to many things such as loss of con idence, sadness, bad mood and fear of being inutile.Furthermore, these lasting feeling may lead to depression (10).
This study aimed to estimate the prevalence of lower back pain and to describe the level of functional incapacity in construction workers, all while examining the relationships between: pain and time of service; functional incapacity and pain and level of pain with the functional incapacity.

Methods
This study was quantitative, transversal and crosssectional in nature (3).It was conducted from May to August 2013 on various construction professionals such as bricklayers, shipowners, carpenters, foreman, mini crane operators and general laborers from a construction company located in Sao Luis.The workers were informed of the study and those who wished to participate signed a TCLE agreement.
This study was carried out in accords with resolution 196/96 from the National Health Council (11) and the Helsinki Convection (12).The trial was approved by UNICEUMA committee of Ethics and Research number 285.014.
In total, 84 workers participated in this study who had been working for at least 6 months with the company.The study excluded workers who admitted to using pain relievers often.
The data was obtained through three questionnaires that were completed during individual's work time.The irst questionnaire was designed to answer demographic variables such as age, profession, civil state, education and ethnicity.Furthermore, other variables were taken into consideration such as smoking, drinking, time at company, hours worked, break time at work, physical exertion, frequency of lower back pain.
The second questionnaire was created by Monnerat and Pereira (13) to measure the intensity of the lower back pain in the individuals.The questionnaire contained 27 questions that assessed the pain intensity through a scale ranging 0 to 4, along with descriptions of the individual's daily activities.The third questionnaire conducted by Roland-Morris is called functional incapacity.It was translated to Portuguese by Nusbaum et al. (14) and consists of 24 alternatives to daily labor activities that may help ease lower back pain.
The study utilized the program SSPSS 18.0 to analyze the data recorded.For the descriptive analysis, the quantitative asymmetric variables were described in median values, with minimum and maximum values described as frequencies and percentages.This was done in order to measure the relationship between lower back pain and functional incapacity.The Mann Whitney U Test was performed in order to measure the relationship between lower back pain and time of service.Furthermore, the Mann Whitney U was used again to analyze functional incapacity and pain as asymmetric data with the help of Spearman's lower back pain intensity correlation, with a signi icancy of 5 % (P ≤ 0, 05).
The prevalence of lower back pain among the workers was 60 (71.4%).This pain was more frequent during the course of labor (Figure 1).The mean pain intensity was 4.5 (0 -32) and the functional incapacity was 3 (0 -19).The scale of functional incapacity by Roland -Morris showed 42 (50%) of the participants responded the second question and 40 (47.6%) the sixth question.
Source: Research data.All participants performed 8 hours of labor and had a one hour break.Most (91.7%) reported signi icant physical exertion.Overall, the workers' time of service was 60 (1 -480) months.
The average, workers' time of service that experienced pain was 60 months (4 -480) and those who did not, 72 months (1 -360).The Mann -Whitney U test was used to analyze the relationship between time of service and pain with a factor of 705 and probability of 0.88.
The descriptive statistics showed that participants who felt lower back had a lower level of disability (average = 2) compared with participants who did not joints, causing fatigue and pain by the end of the day ( 22).This study corroborates with the reports given by workers who felt pain at home after a day's work.
The workers interviewed did not show signi icant levels of functional incapacity at the time of this research, displayed by a median of 3. Arantes, Nunes and Pernambuco (23) showed similar results, by ranking functional incapacity from 1 -3.This score was insigni icant at determining some types of functional incapacity in workers assessed.Sardá Júnior, Nicholas, Pimenta, Asghari and Thieme (24) observed that people who felt pain and did not stop working because of it, leading to lower mean scores of functional incapacity.
The questionnaire of functional incapacity by Roland -Morris showed that those interviewed responded to the second and sixth questions that referred to the cause of lower back pain as changing positions in order to be comfortable, which in turn cause them to rest more often (14).
An important fact found from this study is that the majority of workers (91.7%) reported performing signi icant physical exertion during labor.Batiz, Nunes and Licea (25) found in their study that physical exertion is one of the signi icant causes of lower back pain in workers.This situation is compounded by the association of physical overload and inadequate postures during laborious activity (26).
Studies have shown (21, 27) that weekly work with poor posture adopted in the labor are the most signi icant factors that cause pain.These factors may explain the reason why present research has showed longer work time does not in luence lower back pain in workers.
Moreover in a study performed by Gloria and Gonzalez (28), it was found that all workers who were exposed to lower back pain showed some signs of functional incapacity.Torres, Silva and Xavier (29) reported that workers who had experienced musculoskeletal symptoms in their lower back region had a lower level of functional incapacity in relation to the level of pain in that region.
This study showed that lower back pain did not cause functional incapacity; a fact that may be explained by a slightly lower back pain intensity observed in these workers.
Other studies have shown that lower back pain intensity was correlated to level of incapacity (7,30,31).This leads us to conclude that lower back pain is a musculoskeletal symptom that negatively affects a person's ability to perform laborious activity.fell pain (average = 6); although, the Mann Whitney U test was 257 with an associated probability of 0.14.

Discussion
The present study displayed a higher prevalence of lower back pain in construction worker, 71.4%.Our data was similar to Saad's study (15) accomplished in Ponta Grossa -PR, where 68.13% of the masons reported pain in some part of the body and 59.67% being lower back pain.
An international study was similarly conducted in Holland with masons showed 42% prevalence of individuals with lower back pain which increased to 53% after 1 year (16).Compared to other similar labor activities (17,18,19) lower back pain presented higher prevalence.
In this present study, lower back pain was more common during laborious activity.Xavier, Michaloski and Saad (20) reported that pain occurred more often due to the rapidly changing positions including twisting, inclining, repetition and lifting.
In contrast with the study by Tsuchiya, Mendonça and Cesar (21) the workers that were interviewed reported pain at the end of their work day because of their work day posture.The extensive laborious activity experienced by the workers puts a heavy strain on the muscles and

Conclusion
The data obtained this research showed an explicitly high prevalence of lower back pain in construction workers, while pain intensity remained mild in scale.Furthermore, a close relationship between pain and physical exertion was observed during laborious activity.
In addition, this study did not ind a signi icant level of functional incapacity in workers.Also, time worked did not in luence lower back pain, which may just be due to everyday activities.
All research objectives within this study were met and succeeded previous knowledge on this particular topic.This study highlights the need for further research upon musculoskeletal symptoms experienced by construction workers for a better understanding of the problems associated and future mitigation.

Figure 1 -
Figure 1 -The time of day when the construction workers feel back pain.São Luis -MA, 2013.
Source: Research data.