Ingrid Heuch

The impact of body mass index on the prevalence of low back pain: the HUNT study.

Study Design. A cross-sectional population-based study. Objective. To examine the association between body mass index and chronic low back pain, with adjustment for potential confounders. Summary of Background Data. Although many studies have investigated this association, it is still unclear whether there is a general relationship between body mass index and low back pain which applies to all populations. Methods. This study is based on data collected in the HUNT 2 study in the county of Nord-Trøndelag in Norway between 1995 and 1997. Among a total of 92,936 persons eligible for participation, 30,102 men and 33,866 women gave information on body mass index and indicated whether they suffered from chronic low back pain (69% participation rate). A total of 6293 men (20.9%) and 8923 women (26.3%) experienced chronic low back pain. Relations were assessed by logistic regression of low back pain with respect to body mass index and other variables. Results. In both sexes, a high body mass index was significantly associated with an increased prevalence of low back pain. In men the estimated OR per 5 kg/m2 increase in body mass index was 1.07 (95% CI: 1.03–1.12) and in women 1.17 (95% CI: 1.14–1.21), after adjustment for age, with a significantly stronger association in women. Additional adjustment for education, smoking status, leisure time physical activity, employment status, and activity at work hardly affected these associations. No interactions were found with most other factors. Conclusion. This large population-based study indicates that obesity is associated with a high prevalence of low back pain. Further studies are needed to determine if the association is causal.

Body mass index as a risk factor for developing chronic low back pain: a follow-up in the Nord-Trøndelag Health Study.

Study Design. A population-based, prospective cohort study. Objective. To determine whether overweight, obesity, or more generally an elevated body mass index (BMI) increase the probability of experiencing chronic low back pain (LBP) after an 11-year period, both among participants with and without LBP at baseline. Summary of Background Data. Chronic LBP is a common disabling disorder in modern society. Cross-sectional studies suggest an association between an elevated BMI and LBP, but it is not clear whether this is a causal relationship. Methods. Data were obtained from the community-based HUNT 2 (1995–1997) and HUNT 3 (2006–2008) studies of an entire Norwegian county. Participants were 8733 men and 10,149 women, aged 30 to 69 years, who did not have chronic LBP at baseline, and 2669 men and 3899 women with LBP at baseline. After 11 years, both groups indicated whether they currently had chronic LBP, defined as pain persisting for at least 3 months continuously during the last year. Results. A significant positive association was found between BMI and risk of LBP among persons without LBP at baseline. The odds ratio for BMI 30 or more versus BMI less than 25 was 1.34 (95% confidence interval [CI], 1.08–1.67) for men and 1.22 (95% CI, 1.03–1.46) for women, in analyses adjusted for age, education, work status, physical activity at work and in leisure time, smoking, blood pressure, and serum lipid levels. A significant positive association was also established between BMI and recurrence of LBP among women. LBP status at baseline had negligible influence on subsequent change in BMI. Conclusion. High values of BMI may predispose to chronic LBP 11 years later, both in individuals with and without LBP. The association between BMI and LBP is not explained by an effect of LBP on later change in BMI.

Associations between serum lipid levels and chronic low back pain.

Background: Low back pain may be related to abnormal lipid levels because of atherosclerosis in arteries supplying the lumbar region. Methods: In the cross-sectional HUNT 2 study in the Norwegian county of Nord-Trøndelag, lipid levels were measured in 33,962 women and 30,031 men. A total of 8954 women (26%) and 6273 men (21%) reported suffering from low back pain continuously for at least 3 months in the past year. Results: In age-adjusted analyses, the prevalence of low back pain was inversely associated with HDL cholesterol and positively associated with triglycerides, with stronger associations in women than in men. Relatively weak associations remained in women after adjustment for smoking, physical activity, education, work status, blood pressure, and body mass, but no associations remained among men. Total cholesterol levels were unrelated to low back pain in either sex after age adjustment. Conclusions: The results are partly consistent with the atherosclerosis hypothesis.

Blood pressure as a risk factor for headache and migraine: a prospective population-based study.

During the past decade, several population‐based studies have found an inverse association between blood pressure (BP) and headache. However, most of them have a cross‐sectional design or lack a validated definition of a headache‐free population at baseline. Therefore, additional population‐based studies using a clearly defined headache‐free population and a prospective design are warranted.

Acute low back usually resolves quickly but persistent low back pain often persists

OBJECTIVE To review the evidence of clinical course of pain and disability in patients with acute and persistent low-back pain, and to investigate whether pain and disability had similar courses. DATA SOURCES MEDLINE, CINAHL and Embase databases were searched from 1950 to November, 2011. This search was supplemented by searching of reference lists from eligible studies. STUDY SELECTION Inception cohort studies involving patients with acute (< 6 weeks) and persistent (≥ 6 weeks) low-back pain in which pain or disability outcomes were reported. DATA EXTRACTION Two reviewers extracted data and discrepancies were resolved by consulting a third reviewer. Methodological quality was assessed using 5 criteria suggested by Altman (2001). A meta-analysis of pain and disability outcome data was conducted, in which pain and disability were modelled as a function of time. DATA SYNTHESIS Of 28 613 studies initially identified by the search, 43 studies (33 cohorts) with a total of 11 166 patients met the selection criteria. Data quality was insufficient in many of the studies; only 52% of the studies explicitly reported methods for assembling a representative sample, 73% had a follow-up of at least 80%, and 88% had a follow-up for at least one prognosis outcome at three months or longer. Based on the quantitative pooling of 24 cohorts and 4994 patients the variance-weighted mean pain score (0-100) was 52 (95% CI 48 to 57) at baseline, 23 (95% CI 21 to 25) at 6 weeks, 12 (95% CI 9 to 15) at 26 weeks, and 6 (95% CI 3 to 10) at 52 weeks after the onset of pain for cohorts with acute pain. Among cohorts with persistent pain, the variance-weighted mean pain score (out of 100) was 51 (95% CI 44 to 59) at baseline, 33 (95% CI 29 to 38) at 6 weeks, 26 (95% CI 20 to 33) at 26 weeks, and 23 (95% CI 16 to 30) at 52 weeks after the onset of pain. The course of disability outcomes was similar to the time course of pain outcomes in the acute pain cohorts, but for persistent pain cohorts disability only improved slowly, despite substantial initial improvement in pain. There were large within-study and between-study variation in outcomes. CONCLUSION Most people who seek care for acute or persistent low-back pain improved markedly within the first six weeks, but afterwards improvement slowed. Low to moderate levels of pain and disability were still present at one year, especially in people with persistent pain.

Association between body height and chronic low back pain: a follow-up in the Nord-Trøndelag Health Study

Objective To study potential associations between body height and subsequent occurrence of chronic low back pain (LBP). Design Prospective cohort study. Setting The North-Trøndelag Health Study (HUNT). Data were obtained from a whole Norwegian county in the HUNT2 (1995–1997) and HUNT3 (2006–2008) surveys. Participants Altogether, 3883 women and 2662 men with LBP, and 10 059 women and 8725 men without LBP, aged 30–69 years, were included at baseline and reported after 11 years whether they suffered from LBP. Main outcome measure Chronic LBP, defined as pain persisting for 3 months during the previous year. Results Associations between body height and risk and recurrence of LBP were evaluated by generalised linear modelling. Potential confounders, such as BMI, age, education, employment, physical activity, smoking, blood pressure and lipid levels were adjusted for. In women with no LBP at baseline and body height ≥170 cm, a higher risk of LBP was demonstrated after adjustment for other risk factors (relative risk 1.19, 95% CI 1.03 to 1.37; compared with height <160 cm). No relationship was established among men or among women with LBP at baseline. Conclusions In women without LBP, a body height ≥170 cm may predispose to chronic LBP 11 years later. This may reflect mechanical issues or indicate a hormonal influence.

A Comparison of Anthropometric Measures for Assessing the Association between Body Size and Risk of Chronic Low Back Pain: The HUNT Study

Background Previous work indicates that overweight and obese individuals carry an increased risk of experiencing chronic low back pain (LBP). It is not known, however, how the association with body size depends on the choice of anthropometric measure used. Objective This work compares relationships with LBP for several measures of body size. Different results may indicate underlying mechanisms for the association between body size and risk of LBP. Methods In a cohort study, baseline information was collected in the community-based HUNT2 (1995–1997) and HUNT3 (2006–2008) surveys in Norway. Participants were 10,059 women and 8725 men aged 30–69 years without LBP, and 3883 women and 2662 men with LBP at baseline. Associations with LBP at end of follow-up were assessed by generalized linear modeling, with adjustment for potential confounders. Results Relationships between waist-hip-ratio and occurrence of LBP at end of follow-up were weak and non-significant after adjustment for age, education, work status, physical activity, smoking, lipid levels and blood pressure. Positive associations with LBP at end of follow-up were all significant for body weight, BMI, waist circumference and hip circumference after similar adjustment, both in women without and with LBP at baseline, and in men without LBP at baseline. After additional mutual adjustment for anthropometric measures, the magnitude of the association with body weight increased in women without LBP at baseline (RR: 1.130 per standard deviation, 95% CI: 0.995–1.284) and in men (RR: 1.124, 95% CI 0.976–1.294), with other measures showing weak associations only. Conclusion Central adiposity is unlikely to play a major role in the etiology of LBP. Total fat mass may be one common factor underlying the associations observed. The association with body weight remaining after mutual adjustment may reflect mechanical or structural components behind the relationship between overweight or obesity and LBP.

Do abnormal serum lipid levels increase the risk of chronic low back pain? The Nord-Trøndelag Health Study

Background Cross-sectional studies suggest associations between abnormal lipid levels and prevalence of low back pain (LBP), but it is not known if there is any causal relationship. Objective The objective was to determine, in a population-based prospective cohort study, whether there is any relation between levels of total cholesterol, high density lipoprotein (HDL) cholesterol and triglycerides and the probability of experiencing subsequent chronic (LBP), both among individuals with and without LBP at baseline. Methods Information was collected in the community-based HUNT 2 (1995–1997) and HUNT 3 (2006–2008) surveys of an entire Norwegian county. Participants were 10,151 women and 8731 men aged 30–69 years, not affected by chronic LBP at baseline, and 3902 women and 2666 men with LBP at baseline. Eleven years later the participants indicated whether they currently suffered from chronic LBP. Results Among women without LBP at baseline, HDL cholesterol levels were inversely associated and triglyceride levels positively associated with the risk of chronic LBP at end of follow-up in analyses adjusted for age only. Adjustment for the baseline factors education, work status, physical activity, smoking, blood pressure and in particular BMI largely removed these associations (RR: 0.96, 95% CI: 0.85–1.07 per mmol/l of HDL cholesterol; RR: 1.16, 95% CI: 0.94–1.42 per unit of lg(triglycerides)). Total cholesterol levels showed no associations. In women with LBP at baseline and men without LBP at baseline weaker relationships were observed. In men with LBP at baseline, an inverse association with HDL cholesterol remained after complete adjustment (RR: 0.83, 95% CI: 0.72–0.95 per mmol/l). Conclusion Crude associations between lipid levels and risk of subsequent LBP in individuals without current LBP are mainly caused by confounding with body mass. However, an association with low HDL levels may still remain in men who are already affected and possibly experience a higher pain intensity.

Chronic musculoskeletal complaints as a predictor of mortality-The HUNT study.

Abstract The impact of chronic musculoskeletal complaints (CMSC) and chronic widespread chronic musculoskeletal complaints (CWMSC) on mortality is controversial. The aim of this study was to investigate the relationship between these conditions and mortality. In this prospective population-based cohort study from Norway, baseline data from the second Nord-Trøndelag Health Survey (HUNT2, performed 1995-1997) were linked to the comprehensive National Cause of Death Registry in Norway with follow-up through the year 2011. A total of 65,026 individuals (70%) participated and were categorized based on their response to CMSC questions in HUNT2 (no CMSC, CMSC, or CWMSC). Hazard ratios (HRs) of mortality during a mean of 14.1 years of follow-up were estimated using Cox regression. During the follow-up period, 12,521 subjects died, 5162 from cardiovascular diseases, 3478 from cancer, and 3881 from all other causes. In the multivariate-adjusted analyses, there was no difference in all-cause mortality between individuals with or without CMSC (HR 1.01, confidence interval, 0.97-1.05) and CWMSC (HR 1.01, confidence interval, 0.96-1.05). Similarly, there was no association between CMSC or CWMSC and cardiovascular mortality, mortality from cancer, or mortality from all other causes. Therefore, from this study, we conclude that there is no evidence for a higher mortality rate among individuals with CMSC or CWMSC.

Physical activity level at work and risk of chronic low back pain: A follow-up in the Nord-Trøndelag Health Study

Background Physical activity in leisure time seems to reduce the risk of low back pain, but it is not known whether occupational activity, as recorded in a representative working population, produces a higher or lower risk. Objective To study associations between physical activity level at work and risk of chronic low back pain. Methods Associations were examined in a Norwegian prospective study using data from the HUNT2 and HUNT3 surveys carried out in the whole county of Nord-Trøndelag. Participants were 7580 women and 7335 men who supplied information about physical activity level at work. Levels considered were sedentary work, work involving walking but no heavy lifting, work involving walking and heavy lifting, and particularly strenuous physical work. Nobody in the cohort was affected by chronic low back pain at baseline. After 11 years, participants reported whether they suffered from chronic low back pain. Generalized linear modelling with adjustment for potential confounders was applied to assess associations with risk factors. Results In age-adjusted analyses both women and men showed statistically significant associations between physical activity at work and risk of chronic low back pain, suggesting positive relationships. For particularly strenuous physical work the relative risk of chronic low back pain was 1.30 (95% CI: 1.00–1.71) in women and 1.36 (95% CI 1.17–1.59) in men, compared to sedentary work. Women still showed a general association with activity level after adjustment for education, leisure time physical activity, BMI, smoking and occupational category. In men, the higher risk was only maintained for particularly strenuous work. Conclusion In this cohort, women had a higher risk of chronic low back pain with work involving walking and heavy lifting or particularly strenuous work, compared to sedentary work. Men participating in particularly strenuous work also experienced a higher risk of chronic low back pain.