Obesity as a Risk Factor for Sciatica: A Meta-analysis

Rahman Shiri; Tea Lallukka; Jaro Karppinen; Eira Viikari-Juntura

Disclosures

Am J Epidemiol. 2014;179(8):929-937. 

In This Article

Abstract and Introduction

Abstract

The aim of this study was to assess the associations of overweight and obesity with lumbar radicular pain and sciatica using a meta-analysis. We searched the PubMed, Embase, Scopus, and Web of Science databases from 1966 to July 2013. We performed a random-effects meta-analysis and assessed publication bias. We included 26 (8 cross-sectional, 7 case-control, and 11 cohort) studies. Both overweight (pooled odds ratio (OR) = 1.23, 95% confidence interval (CI): 1.14, 1.33; n = 19,165) and obesity (OR = 1.40, 95% CI: 1.27, 1.55; n = 19,165) were associated with lumbar radicular pain. The pooled odds ratio for physician-diagnosed sciatica was 1.12 (95% CI: 1.04, 1.20; n = 109,724) for overweight and 1.31 (95% CI: 1.07, 1.62; n = 115,661) for obesity. Overweight (OR = 1.16, 95% CI: 1.09, 1.24; n = 358,328) and obesity (OR = 1.38, 95% CI: 1.23, 1.54; n = 358,328) were associated with increased risk of hospitalization for sciatica, and overweight/obesity was associated with increased risk of surgery for lumbar disc herniation (OR = 1.89, 95% CI: 1.25, 2.86; n = 73,982). Associations were similar for men and women and were independent of the design and quality of included studies. There was no evidence of publication bias. Our findings consistently showed that both overweight and obesity are risk factors for lumbar radicular pain and sciatica in men and women, with a dose-response relationship.

Introduction

Low back pain is the number 1 debilitating condition globally, and in 2010 it contributed 10.7% to the total number of years lived with disability.[1] Among low back disorders, sciatica and lumbar disc herniation are the most persistent and disabling conditions.[2] Lumbar radicular pain is defined as low back pain radiating to the leg below the knee level, while sciatica is defined as lumbar radicular pain along with clinical findings suggestive of nerve root compression.[2,3] Sciatica is usually caused by compression or irritation of one of the lumbosacral nerve roots, often due to derangement of a lumbar intervertebral disc such as lumbar disc herniation,[4] although other causes for sciatica have also been reported.[5]

The prevalence of lumbar radicular pain during the preceding 12 months ranges between 13% and 36%[6–8] and that of clinically defined sciatica between 2% and 5%.[9–11] The incidence of lumbar radicular pain increases with age, whereas that of nonspecific low back pain tends to decrease with age.[12] Lumbar radicular pain and sciatica have poorer prognoses than nonspecific low-back-pain syndromes, and they can cause prolonged work disability.[2,13]

The etiologies of lumbar radicular pain and sciatica are not well known, but they seem to be multifactorial. Known risk factors for lumbar radicular pain and sciatica include occupational workload, such as carrying heavy items, bending, or kneeling,[14,15] and body height.[16,17] Lifestyle risk factors have also been suggested as possible risk factors for lumbar radicular pain and sciatica.[18]

Obesity is a prevalent public health problem and is associated with various outcomes—in addition to cardiovascular diseases, obesity has recently been associated with musculoskeletal disorders.[18,19] Previously we conducted a systematic review on the associations of weight-related factors with lumbar radicular pain and sciatica.[18] Based on a qualitative assessment of 13 studies, we found associations of weight-related factors with lumbar radicular pain or sciatica in 1 out of 4 cross-sectional studies, 3 out of 4 case-control studies, and 3 out of 5 cohort studies. Thus, so far it is unknown whether only obesity is associated with lumbar radicular pain and sciatica or both overweight and obesity are associated. We also performed a meta-analysis on the relationships of overweight and obesity with nonspecific low back pain.[19] Both overweight and obesity were associated with an increased risk of nonspecific low back pain.

So far, the roles of overweight and obesity in lumbar radicular pain or sciatica, as more specific or objectively assessed outcomes, have not been addressed with a meta-analysis. Our aim was to carry out a meta-analysis to estimate the magnitude of the associations of overweight and obesity with lumbar radicular pain and/or sciatica. To include studies published after our qualitative review, a period comprising the past 8 years, we updated our search and reassessed the previous studies regarding their eligibility for the meta-analysis.

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