Head Injury and Amyotrophic Lateral Sclerosis: A Meta-Analysis

Guodong Liu; Shan Ou; Huijie Cui; Xuan Li; Zhiyong Yin; Dongqing Gu; Zhengguo Wang

doi:10.1159/000510987

Head Injury and Amyotrophic Lateral Sclerosis: A Meta-Analysis

Neuroepidemiology. 2021 Feb 23:1-9. doi: 10.1159/000510987. Online ahead of print.

Authors

Guodong Liu¹, Shan Ou², Huijie Cui³, Xuan Li¹, Zhiyong Yin⁴, Dongqing Gu³, Zhengguo Wang⁵

Affiliations

¹ The Eighth Department, State Key Laboratory of Trauma, Burn and Combined Injuries, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China.
² Department of Anesthesiology, First People's Hospital of Chengdu, Chengdu, China.
³ Department of Epidemiology and Biostatistics, First Affiliated Hospital, Army Medical University, Chongqing, China.
⁴ The Fourth Department, State Key Laboratory of Trauma, Burn and Combined Injuries, Institute for Traffic Medicine, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China.
⁵ The Fourth Department, State Key Laboratory of Trauma, Burn and Combined Injuries, Institute for Traffic Medicine, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing, China, wangzhg@cae.cn.

PMID: 33621971
DOI: 10.1159/000510987

Abstract

Background: Prior studies have suggested that head injury might be a potential risk factor of amyotrophic lateral sclerosis (ALS). However, the association has not been well established. We aimed to provide a synopsis of the current understanding of head injury's role in ALS.

Methods: We performed a systematic search in PubMed for observational studies that quantitatively investigated the association between head injury and ALS risk published before April 10, 2020. We used a random-effects model to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

Results: Fourteen eligible articles including 10,703 cases and 2,159,324 controls were selected in current meta-analysis. We found that head injury was associated with an increased risk of ALS (OR = 1.38, 95% CI: 1.20-1.60) and the association was slightly stronger concerning severe head injury and ALS risk (OR = 1.69, 95% CI: 1.27-2.23). Considering the number of head injuries (N) and ALS risk, the association was weak (OR = 1.23, 95% CI: 1.10-1.37, N = 1; OR = 1.29, 95% CI: 0.89-1.86, N ≥ 2). In addition, a strong association with ALS risk was found in individuals who suffered head injury <1 year (OR = 4.05, 95% CI: 2.79-5.89), and when the time lag was set at 1-5, 5-10, and >10 years, the pooled OR was 1.13, 1.35, and 1.10, respectively.

Conclusion: This meta-analysis indicates that head injury, especially severe head injury, could increase ALS risk. Although a strong association is found between head injury <1 year and ALS risk in the current study, this result suggests a possibility of reverse causation.

Keywords: Amyotrophic lateral sclerosis; Head injury; Meta-analysis; Risk factor.

Publication types

Systematic Review