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Revista de Saúde Pública

On-line version ISSN 1518-8787

Rev. Saúde Pública vol.51  supl.1 São Paulo  2017  Epub June 01, 2017

http://dx.doi.org/10.1590/s1518-8787.2017051000052 

Original Articles

Factors associated with chronic back pain in adults in Brazil

Deborah Carvalho MaltaI 

Max Moura de OliveiraII 

Silvânia Suely Caribé de Araújo AndradeIII 

Waleska Teixeira CaiaffaIV 

Maria de Fatima Marinho de SouzaIII 

Regina Tomie Ivata BernalV 

IDepartamento de Enfermagem Materno Infantil e Saúde Pública. Escola de Enfermagem. Universidade Federal de Minas Gerais. Belo Horizonte, MG, Brasil

II Programa de Pós-Graduação. Faculdade de Saúde Pública. Universidade de São Paulo. São Paulo, SP, Brasil

IIIDiretoria de Vigilância de Doenças e Agravos Não Transmissíveis. Secretaria de Vigilância em Saúde. Ministério da Saúde. Brasília, DF, Brasil

IVObservatório de Saúde Urbana de Belo Horizonte. Departamento de Medicina Preventiva e Social. Faculdade de Medicina. Universidade Federal de Minas Gerais. Belo Horizonte, MG, Brasil

VNúcleo de Pesquisas Epidemiológicas em Nutrição e Saúde. Universidade de São Paulo. São Paulo, SP, Brasil

ABSTRACT

OBJECTIVE

To identify associations of chronic back pain with sociodemographic characteristics, lifestyles, body mass index, self-reported chronic diseases and health assessment, according to sex.

METHODS

We analyzed data from the 2013 National Health Survey, estimated the prevalence and their respective 95% confidence intervals (95%CI) of chronic back pain, according to selected variables and performed adjustment by age and education.

RESULTS

18.5% of the Brazilian population reported chronic back pain, 15.5% (95%CI 14.7–16.4) of them being men and 21.1% (95%CI 20.2–22.0) being women. The characteristics that remained associated and statistically significant (p < 0.05) after adjustment, in men, were: age group, higher in men with 65 years or older (ORa = 6.06); low education level; living in rural area; history of smoking, high salt intake, increase in the time of heavy physical activity at work and at home; being overweight (ORa = 1.18) or obese (ORa = 1.26); diagnostic of hypertension (ORa = 1.42), high cholesterol (ORa = 1.60); and worse health assessment in comparison with very good (good [ORa = 1.48]; regular [ORa = 3.22]; poor [ORa = 5.00], very poor [ORa = 8.60]). Among women, they were: increase with age, higher among women with 55-64 years (ORa = 3.64); low education level; history of smoking, regular candy consumption, high salt intake, heavy physical activity at work and at home and increase in the time of these activities; being overweight (ORa = 1.23) or obese (ORa = 1.32); diagnosis of hypertension (ORa = 1.50), high cholesterol (ORa = 1.84); and worse health assessment than very good (good [ORa = 1.43]; regular [ORa = 3.16]; poor [ORa = 5.44], very poor [ORa = 8.19]).

CONCLUSIONS

Our findings point out differences by sex and contribute to the knowledge of the panorama of chronic back pain, which, besides affecting individuals, generate negative socioeconomic impacts, by causing work-related disabilities and hindering everyday activities.

Key words: Adult; Low Back Pain, epidemiology; Diagnostic Self Evaluation; Risk Factors; Socioeconomic Factors; Health Surveys

INTRODUCTION

Chronic back pain is one of the commonly reported complaints by the adult population, causing disability, reduced functionality, and absence from work1. This condition includes neck pain, chest pain, sciatica, and low back pain, which can be caused by different musculoskeletal diseases, intervertebral disc disorders, spondylosis or radiculopathy, the two latter being the most frequent ones.a

The cost of these diseases is high, both by the demand for health services, tests, medications, physical therapy, hospitalizations, and surgeries and by the expenses resulting from sick leaves and early retirements2. Social Security data show high rates of disability retirement related to back pain in Brazil (about 30/100,000 taxpayers in 2007), the highest among men and in older individuals3.

Analyses of the National Household Sample Survey (PNAD) in 2003 have already indicated back pain as the most reported among the surveyed chronic diseases, affecting 13.2% of the adult population4. In PNAD 2008, it was reported by 13.5% of adults, presenting itself as the second most reported cause, being more prevalent in women and overcoming the prevalence of 30% after 50 years of age and in individuals with low education level5.

It is estimated that from 70% to 85% of the population will have some episode of back pain in the course of life, which can be caused by anatomophysiological changes, as the wear on the musculoskeletal components of spinal support, pregnancy2,6,7, inflammatory, degenerative and neoplastic processes, birth defects (lordosis, kyphosis, muscle weakness), in addition to external causes (traffic accidents, falls, among others)b. The literature indicates a set of factors associated with chronic back pain, such as demographics factors (age, sex, income, and education), lifestyles (smoking and low physical activity, or strenuous physical work), and metabolic risk factors (obesity and other chronic diseases)2,c.

In 2013, chronic back problems were investigated on the National Health Survey (PNS), making it possible to analyze these data along with other health conditions and sociodemographic data that represent the Country. This study aimed to identify associations of chronic back pain with sociodemographic characteristics, lifestyles, body mass index, self-reported chronic diseases and health assessment, according to sex.

METHODS

This is a cross-sectional study with data from the National Health Survey (PNS) of 2013, conducted by the Brazilian Institute of Geography and Statistics (IBGE) in partnership with the Brazilian Ministry of Health. PNS represents adults living in private households in urban and rural areas of the Country, in the five geographical macroregions, in the 27 Federative Units (UF), and in the Brazilian capitals8,d.

The sampling was conglomerated in three stages. In the first stage, we selected the census tracts; in the second stage, the households; and in the third stage, a resident with 18 years or older. The final sample was composed by 64,348 households, with 60,202 conducted interviews. We performed a weighting considering weights for each stage of selection of the sample and for non-response, so that the sample could represent the Country and the studied geographic strata8,d.

The data were collected using handheld computers (Personal Digital Assistance). The module on chronic diseases was answered by the adult selected for individual interview8,d.

The outcome examined in this study was the prevalence of chronic back pain, measured by the question: “Do you have a chronic back problem, such as chronic back or neck pain, low back pain, sciatica, vertebrae or disc problems?” The response options were “yes” or “no.”

The explanatory variables were: a) sociodemographic characteristics: sex; age group in years (18–24, 25–34, 35–44, 45–54, 55–64, 65 or older); education level; race or skin color (white, black, brown); area of residence (urban, rural); b) lifestyles as risk and protective factors: smoking; abusive consumption of alcohole; consumption of red meat with fat; regular candy consumption; regular soda consumptionf; high salt intake; recommended consumption of fruits and vegetables – five or more daily servingsg; insufficient physical activity in four areas – recreation, work, displacement, and domestic activities; heavy physical activity at work – time (minutes) of heavy physical activity at work in a normal day (0, 1-149, 150 or more); heavy physical activity at home – time (minutes) of heavy physical activity at home in a normal day (0, 1-149, 150 or more); watching TV for more than three hours; c) metabolic risk factors: body mass index category (eutrophy, overweight, obesity); self-reported chronic disease: hypertension, diabetes, and high cholesterol; d) health assessment (very good, good, regular, poor, and very poor).

We estimated the prevalence of back pain and respective 95% confidence intervals (95%CI) according to the studied explanatory variables. We estimated the odds ratio (OR) and respective 95%CI crude and adjusted for age and education. The adjustment was carried out to control bias in the estimates, since the literature points out significant differences regarding these variables5. The analysis was conducted in the survey module for complex samples of the Stata program, version 12.1 (StataCorp., CollegeStation, EUA).

The PNS project was approved by the Research Ethics Committee of the Conselho Nacional de Saúde (Process 328,159, June 26, 2013). All participants signed the informed consent form.

RESULTS

In Brazil, chronic back pain was reported by 18.5% of adults: 15.5% (95%CI 14.7–16.4) in men and 21.1% (95%CI 20.2–22.0) in women. In analyzing the chronic back pain, we observed that its prevalence differed according to sex. In both sexes, we verified differences in the reported prevalence with increasing age, low education level, smoking history, heavy activity at work and at home (and the increase in time of these activities), overweight and obesity, worsening of back pain when the health assessment gets worse, and history of hypertension, diabetes, or high cholesterol (Table 1).

Table 1 Prevalence (%) and respective confidence interval (95%CI) of people who reported chronic back pain, according to selected variables, by sex. National Health Survey, Brazil, 2013. 

Variable Male Female


%a 95%CI pb %a 95%CI pb
Age group (years) < 0.01 < 0.01
18–24 5.6 4.4–6.8 10.1 8.3–12
25–34 9.9 8.6–11.2 12.7 11.4–14
35–44 14.7 13–16.3 20 18.3–21.7
45–54 21.6 19.5–23.8 26.8 24.8–28.9
55–64 22.3 19.8–24.8 30.4 27.8–32.9
65 or older 25.5 22.6–28.4 31.3 28.9–33.7
Education level < 0.01 < 0.01
Illiterate/Some elementary or middle school 21.9 20.4–23.4 27.1 25.6–28.5
Elementary or middle school/Some high school 12.5 10.7–14.3 19.1 17.1–21.1
High school/Some higher education 10.5 9.3–11.8 16.9 15.6–18.1
Higher education degree 12 9.8–14.2 16.7 14.7–18.8
Race/skin colorc 0.6 0.02
White 15.9 14.6–17.1 22.2 20.9–23.5
Black 14.4 11.8–17 20.9 18.3–23.5
Brown 15.5 14.4–16.7 19.8 18.5–21
Area < 0.01 0.43
Urban 14.6 13.7–15.5 20.9 20–21.9
Rural 20.7 18.7–22.8 21.9 19.6–24.3
Smoking < 0.01 < 0.01
Non-smoker 11.8 10.8–12.8 18.5 17.6–19.5
Former smoker 23 21–24.9 30.2 27.8–32.6
Smoker 19 17.1–20.9 26.6 24.1–29.2
Abusive consumption of alcohol 0.47 0.16
No 15.6 14.8–16.5 21.2 20.2–22.1
Yes 14.7 12.5–17 17.8 13.4–22.2
Consumption of red meat with fat 0.05 0.21
Yes 16.4 15.2–17.7 20.3 18.7–21.8
No 14.9 13.9–15.9 21.4 20.3–22.4
Regular candy consumption 0.73 0.18
No 15.5 14.6–16.4 21.4 20.4–22.4
Yes 15.8 14–17.7 20.1 18.4–21.7
Regular soda consumption < 0.01 0.01
No 16.3 15.3–17.3 21.6 20.6–22.6
Yes 13.4 11.8–15 18.9 17.2–20.7
High salt intake 0.36 0.62
No 15.4 14.5–16.3 21.1 20.2–22.1
Yes 16.3 14.4–18.3 20.6 18.5–22.7
Recommended consumption of fruits and vegetables (five or more daily servings) 0.38 < 0.01
Yes 16.5 14.2–18.7 24.1 22–26.1
No 15.4 14.5–16.3 20.4 19.5–21.4
Insufficiently physical active in the four areas < 0.01 0.18
No 15.4 14.4–16.4 21.6 20.4–22.9
Yes 15.8 14.4–17.1 20.6 19.4–21.7
Heavy activity at work < 0.01 < 0.01
No 11.7 10.7–12.7 17.6 16.3–18.8
Yes 18.7 17–20.5 27.7 24.9–30.6
Time (minutes) of heavy physical activity at work in a normal day < 0.01 < 0.01
0 14.9 14–15.7 19.8 18.8–20.7
1–149 17.9 14.1–21.8 23.5 20–27.1
≥ 150 25 20.9–29 25.9 23.9–27.9
Heavy physical activity at home < 0.01 < 0.01
No 14.9 14–15.7 19.8 18.8–20.7
Yes 22 19.2–24.8 25.4 23.5–27.2
Time (minutes) of heavy physical activity at home in a normal day < 0.01 < 0.01
0 14.5 13.5–15.4 20.4 19.5–21.4
1–149 16 11.8–20.2 27.8 21.5–34.1
≥ 150 19.1 17.3–21 27.7 24.5–30.9
Watching TV for more than three hours 0.15 0.76
No 15.9 14.9–16.9 21.2 20.1–22.2
Yes 14.6 13.1–16.1 20.9 19.5–22.3
Classification by BMId 0.09 < 0.01
Normal 15.4 14–16.8 18 16.6–19.3
Overweight 16.3 14.9–17.8 23.5 21.6–25.4
Obesity 18.3 15.9–20.8 25.6 23.3–28
Hypertension < 0.01 < 0.01
No 13.5 12.7–14.4 17.5 16.6–18.4
Yes 24.6 22.3–26.8 32.3 30.4–34.2
Diabetes < 0.01 < 0.01
No 15.2 14.4–16.1 20.3 19.4–21.3
Yes 21.1 17.3–24.9 30.8 27.5–34
Cholesterol < 0.01 < 0.01
No 14.5 13.6–15.3 18.4 17.5–19.3
Yes 25.7 22.7–28.7 36.1 33.7–38.5
Health assessment 0.68 < 0.01
Very good 6.8 5.4–8.3 10.2 8.4–11.9
Good 11.2 10.3–12.2 14.6 13.6–15.6
Regular 25.6 23.7–27.5 30.4 28.7–32.1
Poor 37.5 32.7–42.2 45 41.1–48.9
Very poor 49.6 39.8–59.4 52.5 45.1–59.9
Total 15.5 14.7–16.4 21.1 20.2–22

BMI: body mass index.

a Weighted estimates: selected resident’s weight with correction of non-interview with calibration by population projection for the selected resident.

b Chi-square Test.

c Excluding the categories yellow and indigenous.

d 32% missing data for BMI.

Only in men, we observed higher prevalence of chronic back pain among those who live in rural areas, who consume red meat, and who are insufficiently active in the four areas. In women, we found higher prevalence among those who self-reported as white and those with recommended consumption of fruits and vegetables (Table 1).

Tables 2 and 3 present the estimates of the crude and adjusted OR by age and education, according to sex. After the adjustment, the characteristics that remained associated and statistically significant (p < 0.05) with back pain in men were: a) sociodemographic characteristics (all age groups over 25 years, being higher at 65 years or older; low education level; living in the rural area); b) lifestyles (being a smoker or a former smoker; high salt intake; recommended consumption of fruits and vegetables; heavy activity at work and at home, and the increase in time of these activities); c) metabolic risk factors (being overweight or obese; diagnosis of hypertension; high cholesterol); d) worse health assessment when compared with very good assessment (good, regular, bad, very bad). Being insufficiently physically active protected men from chronic back pain (Table 2).

Table 2 Associated factorsa (crude and adjusted OR and respective 95%CI) in men who reported chronic back pain, according to selected variables. National Health Survey, Brazil, 2013. 

Variable ORcrude 95%CI ORab 95%CI
Age group (years)
18–24 1 1
25–34 1.84 1.41–2.42 1.87 1.42–2.46
35–44 2.9 2.25–3.73 2.73 2.11–3.53
45–54 4.65 3.59–6.02 4.2 3.22–5.47
55–64 4.83 3.68–6.33 4.16 3.16–5.49
65 or older 5.78 4.39–7.62 4.57 3.45–6.06
Education level
Illiterate/Some elementary or middle school 1 1
Elementary or middle school/Some high school 0.51 0.42–0.61 0.7 0.58–0.85
High school/Some higher education 0.42 0.36–0.49 0.59 0.51–0.7
Higher education degree 0.49 0.39–0.61 0.54 0.43–0.67
Race/skin colorc
White 1 1
Black 0.9 0.71–1.13 0.84 0.67–1.05
Brown 0.98 0.87–1.11 0.98 0.86–1.12
Area
Urban 1 1
Rural 1.53 1.32–1.76 1.26 1.08–1.46
Smoking
Non-smoker 1 1
Former smoker 2.23 1.94–2.56 1.54 1.34–1.78
Smoker 1.75 1.5–2.05 1.41 1.2–1.65
Abusive consumption of alcohol
No 1 1
Yes 0.93 0.77–1.13 1.06 0.87–1.28
Consumption of red meat with fat
Yes 1 1
No 0.89 0.79–1 0.92 0.82–1.03
Regular candy consumption
No 1 1
Yes 1.03 0.88–1.2 1.18 1–1.38
Regular soda consumption
No 1 1
Yes 0.79 0.68–0.93 1.01 0.86–1.18
High salt intake
No 1 1
Yes 1.07 0.92–1.25 1.28 1.09–1.49
Recommended consumption of fruits and vegetables (five or more daily servings)
Yes 1 1
No 0.92 0.78–1.1 0.99 0.83–1.19
Insufficiently physical active in the four areas
No 1 1
Yes 1.03 0.91–1.16 0.83 0.72–0.94
Heavy activity at work
No 1 1
Yes 1.73 1.5–2 1.65 1.41–1.92
Time (minutes) of heavy physical activity at work in a normal day
0 1 1
1–149 1.25 0.96–1.62 1.33 0.96–1.84
≥ 150 1.9 1.52–2.38 1.52 1.31–1.77
Heavy physical activity at home
No
Yes 1.61 1.36–1.92 1.6 1.33–1.92
Time (minutes) of heavy physical activity at home in a normal day
0 1 1
1–149 1.13 0.82–1.55 1.3 0.99–1.72
≥ 150 1.4 1.22–1.61 1.81 1.44–2.29
Watching TV for more than three hours
No 1 1
Yes 0.9 0.79–1.04 0.95 0.82–1.09
BMId
Normal 1 1
Overweight 1.15 1.01–1.31 1.18 1.02–1.36
Obesity 1.32 1.11–1.58 1.26 1.05–1.53
Hypertension
No 1 1
Yes 2.08 1.82–2.39 1.42 1.23–1.65
Diabetes
No 1 1
Yes 1.49 1.18–1.88 0.98 0.77–1.23
Cholesterol
No 1 1
Yes 2.04 1.72–2.42 1.6 1.34–1.92
Health assessment
Very good 1 1
Good 1.73 1.36–2.19 1.48 1.16–1.89
Regular 4.68 3.64–6.02 3.22 2.49–4.16
Poor 8.16 6.04–11.01 5 3.67–6.81
Very poor 13.38 8.52–21.02 8.6 5.51–13.44

BMI: body mass index.

a Weighted estimates: selected resident’s weight with correction of non-interview with calibration by population projection for the selected resident.

b OR adjusted by age and education.

c Excluding the categories yellow and indigenous.

d 32% missing data for BMI.

Table 3 Associated factorsa (crude and adjusted OR and respective 95%CI) in women who reported chronic back pain, according to selected variables. National Health Survey, Brazil, 2013. 

Variable ORcrude 95%CI ORab 95%CI
Age group (years)
18–24 1 1
25–34 1.29 1.03–1.62 1.31 1.04–1.65
35–44 2.22 1.76–2.79 2.2 1.74–2.78
45–54 3.25 2.61–4.06 3.11 2.48–3.91
55–64 3.86 3.07–4.87 3.64 2.86–4.62
65 or older 4.04 3.23–5.05 3.62 2.86–4.59
Education level
Illiterate/Some elementary or middle school 1 1
Elementary or middle school/Some high school 0.64 0.55–0.74 0.9 0.77–1.04
High school/Some higher education 0.55 0.49–0.61 0.82 0.73–0.93
Higher education degree 0.54 0.46–0.64 0.68 0.58–0.8
Race/skin colorc
White 1 1
Black 0.93 0.78–1.1 0.88 0.74–1.06
Brown 0.86 0.78–0.95 0.88 0.79–0.97
Area
Urban 1 1
Rural 1.06 0.92–1.23 1 0.85–1.17
Smoking
Non-smoker 1 1
Former smoker 1.9 1.68–2.15 1.46 1.28–1.65
Smoker 1.59 1.38–1.84 1.32 1.13–1.53
Abusive consumption of alcohol
No 1 1
Yes 0.81 0.6–1.09 1.04 0.76–1.43
Consumption of red meat with fat
Yes 1 1
No 1.07 0.96–1.19 1.05 0.94–1.17
Regular candy consumption
No 1 1
Yes 0.92 0.82–1.04 1.14 1.01–1.29
Regular soda consumption
No 1 1
Yes 0.84 0.75–0.96 1.05 0.92–1.19
High salt intake
No 1 1
Yes 0.97 0.84–1.11 1.18 1.02–1.36
Recommended consumption of fruits and vegetables (five or more daily servings)
Yes 1 1
No 0.81 0.72–0.91 0.85 0.75–0.96
Insufficiently physical active in the four areas
No 1 1
Yes 0.94 0.86–1.03 0.84 0.76–0.92
Heavy activity at work
No 1 1
Yes 1.8 1.54–2.11 1.69 1.44–2
Time (minutes) of heavy physical activity at work in a normal day
0 1 1
1–149 1.25 1.02–1.53 1.71 1.23–2.37
≥ 150 1.42 1.27–1.59 1.64 1.38–1.94
Heavy physical activity at home
No 1 1
Yes 1.38 1.24–1.54 1.48 1.32–1.66
Time (minutes) of heavy physical activity at home in a normal day
0 1 1
1–149 1.5 1.09–2.06 1.31 1.05–1.63
≥ 150 1.49 1.26–1.76 1.54 1.36–1.73
Watching TV for more than three hours
No 1 1
Yes 0.98 0.89–1.09 0.96 0.87–1.07
BMId
Normal 1 1
Overweight 1.28 1.13–1.44 1.23 1.09–1.39
Obesity 1.43 1.26–1.63 1.32 1.15–1.51
Hypertension
No 1 1
Yes 2.25 2.04–2.49 1.5 1.34–1.68
Diabetes
No 1 1
Yes 1.74 1.49–2.03 1.11 0.94–1.31
Cholesterol
No 1 1
Yes 2.5 2.23–2.81 1.84 1.63–2.06
Health assessment
Very good 1 1
Good 1.51 1.23–1.85 1.43 1.16–1.76
Regular 3.86 3.14–4.74 3.16 2.55–3.91
Poor 7.24 5.65–9.29 5.44 4.21–7.03
Very poor 9.78 6.89–13.87 7.19 4.95–10.44

BMI: body mass index.

a Weighted estimates: selected resident’s weight with correction of non-interview with calibration by population projection for the selected resident.

b OR adjusted by age and education.

c Excluding the categories yellow and indigenous.

d 32% missing data for BMI.

After the adjustment, the variables that remained associated and statistically significant (p < 0.05) with back pain in women were: a) sociodemographic characteristics (all age groups over 25 years, being higher after 55 years old; low education level); b) lifestyles (being smoker or former smoker; high candy consumption; high salt intake; heavy activity at work and at home, and the increase in time of these activities); c) metabolic risk factors (being overweight or obese; diagnosis of hypertension; high cholesterol); d) worse health assessment when compared with very good assessment (good, regular, poor, very poor). Self-declaring as brown, being insufficiently physically active in the four areas, and having the recommended consumption of fruits and vegetables protected women from back pain (Table 3).

In both sexes, the variables abusive consumption of alcohol, red meat or soda, watching TV for more than three hours and diagnosis of diabetes were not associated with the outcome (Tables 2 and 3).

DISCUSSION

PNS data show that, approximately, one-fifth of the Brazilian population reported chronic back pain. The characteristics associated with higher prevalence of chronic back pain, after the proposed adjustment, in both sexes, were: increasing age; low education level; smoking history; high salt intake; heavy activity at work or at home, and the increase in the time spent on these activities; being overweight or obese; having chronic diseases such as hypertension and high cholesterol; and worse health assessment than very good (good, regular, poor, very poor). In men, living in the rural area remained associated with chronic back pain. In women, the variables brown race/skin color, regular candy consumption, and recommended consumption of fruits and vegetables remained associated as protective factors. In addition, being insufficiently active in the four areas of physical activity protected both sexes from back pain.

The high prevalence of chronic back pain results in limitation of activities, high demand for health services2,9, and, consequently, high social costs, such as reduction of productivity, absenteeism at work and social security expenses7,9,10. PNS showed a higher prevalence of chronic back pain than those estimated by PNAD 2003 and 20084,5.

Women were those who most reported chronic back pain, which has been attributed to the greater awareness of women about the symptoms and signs of diseases2,5. Factors such as performing housework in greater intensity, which remained associated after the adjustment, increased exposure to repetitive work, non-ergonomic position, and work at high speed are also mentioned in the literature2,7. In addition, the differences in the anatomical and functional characteristics of women, such as smaller height, less muscle mass, less bone mass, joints more fragile and less adapted to strenuous physical effort, may result in more overload in the back2,11. Studies also mention pregnancy and postpartum as factors that explain the higher prevalence of back pain among women. In pregnancy, hormones such as relaxin, estrogen, and progesterone, increase the flexibility of the ligaments of the spine and hip, which could lead to lordosis, muscle contractures (because of the weight increase), and posture (because of the fetal growth). In the postpartum, back pain can be related to postural inadequacies while breastfeeding, to the child’s weight and other factors2,12.

Age was an important predictor in crude and adjusted analyses, in both sexes, indicating that the prevalence of chronic pain increases gradually and proportionally with increasing age. This relationship has also been observed in studies with data from PNAD 2003 and 20084,5. The observed dose-response can be explained by changes in the body due to the aging process, such as postural problems, reduced flexibility, greater musculoskeletal degeneration, and, consequently, worsening pain. In addition, the back pain found in middle-aged adults (40 to 49 years), an economically active age group, may be associated with work activities2,13,14,15,a.

Low education level and income have also been considered predictive of the development of chronic pain14,15. PNAD also observed that less educated individuals had more chronic pain5. Studies conducted in the South region of the Country7 and in Bambuí (Minas Gerais)12 found association between back pain and low education level. This can be a result of professions that require strenuous work, more physical activity, and less health-care, which are common in populations with less schooling. In this study, similarly, low education level was associated with back pain in both sexes. Still, men living in rural areas had higher association with back pain, which can be explained by the more strenuous work in rural areas.

This study found that brown women were protected against back pain. Although Webb et al.15 found increased risk in Asians, race and ethnicity have not been reported as factors associated with the presence of chronic pain13. The self-reported race/skin color may have influenced the results found here. Therefore, these data need to be confirmed in further studies.

Evidence show that smokers and former smokers are more prone to develop chronic pain13,15,16, because nicotine could lead to an activation of the immune system, predisposing to rheumatic diseases and back pain, among other conditions. This study found higher prevalence of back pain in smokers and former smokers, in both sexes, both in the crude analysis and after adjustment for age and education.

The outcome remained associated with intense or heavy physical activity at work or at home, in both sexes. Heavy physical activity is not considered beneficial to health, because it is associated with fatigue, muscle and joint overload, leading to musculoskeletal problems2.

The chronic back problem limits usual activities, which is worrisome, since these limitations affect adults in the economically active age group and decrease functional capacity at work and in daily activities, interfering in their quality of life17.

This study also indicated, for both sexes, that overweight and obesity are associated with chronic back pain, confirming other studies13,16-18. Increased weight leads to muscle overload, as well as to inflammatory processes in the bones and spinal disc damage, favoring the onset of low back pain and herniated disc, among other back diseases. Public policies aiming the reduction of obesity should be prioritized13,18, because weight loss can decrease pain and disability.

The presence of chronic diseases, such as hypertension and high cholesterol, was also associated with chronic back pain in this study. This may be related to the aging process, since there is greater risk of comorbidities with increasing age4,5. We also observed that, the worse the health self-assessment, the greater the association with chronic back problem. Studies show that a worse health self-assessment is associated with worse health outcomes (including chronic back pain) and higher morbidity, and these characteristics were present in both sexes2,19.

The adequate consumption of fruits and vegetables helps in maintaining appropriate concentration levels of micronutrients, such as vitamin K. Low consumption increases the risk of fractures and less bone mass20; however, in this study, we found an inverse association in women. A possible explanation is that the increased consumption of fruits and vegetables has occurred after the back pain, as orientation to healthy nutrition and weight control, resulting in reverse causality.

Cross-sectional studies as this are advantageous regarding quickness and low cost. However, there are inherent limitations to this design, such as the possibility of reverse causality. In this study, this characteristic may have affected the associations found between the studied outcome and the variables related to lifestyle and medical diagnoses; however, we believe not in the case of associations related to socioeconomic variables.

In addition, there is the possibility of overestimation of prevalence, since the chronic pain was self-reported. The recognition of the disease by the individual depends on the degree of perception, frequency of signs and symptoms, and access to medical services, health professionals, and diagnostic tests.

Associations tended to be similar between sexes, indicating that back problems are related to the studied factors, with great magnitude and regardless of sex for some, except for the variables race/skin color and area of residence. Thus, our findings contribute to the knowledge of the panorama of these diseases that, besides affecting the individual, generate negative socioeconomic impacts, especially by causing work-related disabilities and hindering everyday activities. Specific health interventions are needed for the population groups that have higher prevalence of back problem.

REFERENCES

1. Reis RJ, Pinheiro TMM, Navarro A, Martin MM. Perfil da demanda atendida em ambulatório de doenças profissionais e a presença de lesões por esforços repetitivos. Rev Saude Publica. 2000;34(3):292-8. https://doi.org/10.1590/S0034-89102000000300013. [ Links ]

2. Ferreira GD, Silva MC, Rombaldi AJ, Wrege ED, Siqueira FV, Hallal PC. Prevalência de dor nas costas e fatores associados em adultos do Sul do Brasil: estudo de base populacional. Rev Bras Fisioter. 2011;15(1):31-6. https://doi.org/10.1590/S1413-35552011005000001. [ Links ]

3. Meziat Filho N, Silva GA. Invalidez por dor nas costas entre segurados da Previdência Social do Brasil. Rev Saude Publica. 2011;45(3):494-502. https://doi.org/10.1590/S0034-89102011000300007. [ Links ]

4. Barros MBA, César CLG, Carandina L, Torre GD. Desigualdades sociais na prevalência de doenças crônicas no Brasil, PNAD-2003. Cienc Saude Coletiva. 2006;11(4):911-26. https://doi.org/10.1590/S1413-81232006000400014. [ Links ]

5. Barros MBA, Francisco PMSB, Zanchetta LM, Cesar CLG. Tendências das desigualdades sociais e demográficas na prevalência de doenças crônicas no Brasil, PNAD: 2003-2008. Cienc Saude Coletiva. 2011;16(9):3755-68. https://doi.org/10.1590/S1413-81232011001000012. [ Links ]

6. Gomes MRA, Araújo RC, Lima AS, Pitangui ACR. Lombalgia gestacional: prevalência e características clínicas em um grupo de gestantes. Rev Dor. 2013;14(2):114-7. https://doi.org/10.1590/S1806-00132013000200008. [ Links ]

7. Silva MC, Fassa AG, Valle NCJ. Dor lombar crônica em uma população adulta no Sul do Brasil: prevalência de fatores associados. Cad Saude Publica. 2004;20(2):377-85. https://doi.org/10.1590/S0102-311X2004000200005. [ Links ]

8. Szwarcwald CL, Malta DC, Pereira CA, Vieira MLFP, Conde WL, Souza Júnior PRB, et al. Pesquisa Nacional de Saúde no Brasil: concepção e metodologia da aplicação. Cienc Saude Coletiva. 2014;19(2):333-42. https://doi.org/10.1590/1413-81232014192.14072012. [ Links ]

9. Bento AAC, Paiva ACS, Siqueira FB. Correlação entre incapacidade, dor – Roland Morris, e capacidade funcional – SF-36 em indivíduos com dor lombar crônica não específica. e-Scientia. 2009 [cited 2017 Jan 17];2(1):1-18. Available from: http://revistas.unibh.br/index.php/dcbas/article/view/142Links ]

10. Moraes MAA. Avaliação da eficácia de um programa de reabilitação como modificador nos indicadores de dor e qualidade de vida em pacientes com lombalgia crônica inespecífica [tese de doutorado]. Campinas: Faculdade de Educação Física da UNICAMP; 2003. [ Links ]

11. Capaldo G. Lombalgia come problema sociale. Scien Riabil. 2005;7(2):5-20. [ Links ]

12. Machado GPM, Barreto SM, Passos VMA, Lima-Costa MFF. Projeto Bambuí: prevalência de sintomas articulares crônicos em idosos. Rev Assoc Med Bras. 2004;50(4):367-72. https://doi.org/10.1590/S0104-42302004000400024. [ Links ]

13. Sá K, Baptista AF, Matos MA, Lessa I. Prevalência de dor crônica e fatores associados na população de Salvador, Bahia. Rev Saude Publica. 2009;43(4):622-30. https://doi.org/10.1590/S0034-89102009005000032. [ Links ]

14. Smith BH, Elliott AM, Chambers WA, Smith WC, Hannaford PC, Penny K. The impact of chronic pain in the community. Fam Pract. 2001;18(3):292-9. https://doi.org/10.1093/fampra/18.3.292. [ Links ]

15. Webb R, Brammah T, Lunt M, Urwin M, Allison T, Symmons D. Prevalence and predictors of intense, chronic, and disabling neck and back pain in the UK general population. Spine. 2003;28(11):1195-202. https://doi.org/10.1097/01.BRS.0000067430.49169.01. [ Links ]

16. Wijhoven HA, Vet HC, Picavet HS. Explaining sex differences in chronic musculoskeletal pain in general population. Pain. 2006;124(1-2):158-66. https://doi.org/10.1016/j.pain.2006.04.012. [ Links ]

17. Oliveira MM, Andrade SSCA, Souza CAV, Ponte JN, Szwarcwald CL, Malta DC. Problema crônico de coluna e diagnóstico de distúrbios osteomusculares relacionados ao trabalho (DORT) autorreferidos no Brasil: Pesquisa Nacional de Saúde, 2013. Epidemiol Serv Saude. 2015;24(2):287-96. https://doi.org/10.5123/S1679-49742015000200011. [ Links ]

18. Picavet HS, Schouten JS. Musculoskeletal pain in the Netherlands: prevalences, consequences and risk groups, the DMC3-study. Pain. 2003;102(1-2):167-78. https://doi.org/10.1016/s0304-3959(02)00372-x. [ Links ]

19. Barreto SM, Figueiredo RC. Doença crônica, autoavaliação de saúde e comportamento de risco: diferença de gênero. Rev Saude Publica. 2009;43 Supl 2:38-47. https://doi.org/10.1590/S0034-89102009000900006. [ Links ]

20. Cockayne S, Adamson J, Lanham-New S, Shearer MJ, Gilbody S, Torgerson DJ. Vitamin K and the prevention of fractures: systematic review and meta-analysis of randomized controlled trials. Arch Intern Med. 2006;166(12):1256-61. https://doi.org/10.1001/archinte.166.12.1256 . [ Links ]

aMinistério da Previdência Social (BR). Relação das 10 maiores frequências de auxílios-doença concedidos segundo os códigos da CID-10 – Acumulado Ano 2007.

bWorld Health Organization. Identification and control of work-related diseases: report of a WHO expert committee meeting, 1983, Geneva. Geneva; 1985. (WHO Technical Report Series, 714).

cNational Institute for Occupational Safety and Health. Musculoskeletal disorders and workplace factors. Cincinnati: NIOSH; 1997. Available from: https://www.cdc.gov/niosh/docs/97-141/pdfs/97-141.pdf

dInstituto Brasileiro de Geografia e Estatística. Pesquisa Nacional de Saúde 2013: percepção do estado de saúde, estilos de vida e doenças crônicas – Brasil, Grandes Regiões e Unidades da Federação. Rio de Janeiro: IBGE; 2014 [cited 2015 Oct 8]. Available from: http://ftp.ibge.gov.br/PNS/2013/pns2013.pdf

eIntake of four or more portions, by women, or five or more portions, by men, on the same occasion, within the last 30 days.

fConsumption of soft drinks or artificial juices five or more days per week.

gDaily intake of at least 400 grams of fruits and vegetables, recommended by the World Health Organization, which amounts to about five daily portions of these foods.

Funding: Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq – Process 307.865/2014-2 - productivity scholarship granted to DCM and 307,731/2013-8 granted to WTC).

Received: May 30, 2016; Accepted: October 17, 2016

Correspondence: Deborah Carvalho Malta. Departamento de Enfermagem Materno Infantil e Saúde Pública, Escola de Enfermagem – UFMG. Av. Alfredo Balena, 190. 30130-100 Belo Horizonte, MG, Brasil E-mail: dcmalta@uol.com.br

Authors’ Contribution: Conception of the study, literature review, data analysis and interpretation, critical review of the text: DCM. Literature review, data analysis, critical review of the text: MMO. Statistical analysis, data analysis and interpretation, critical review of the text: RTIB. Critical review of the manuscript: WTC, SCAA, MFMS. All authors approved the final version and take public responsibility for the article’s content.

Conflict of Interests: The authors declare no conflict of interest.

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