Guodong Liu1, Shan Ou2, Huijie Cui3, Xuan Li1, Zhiyong Yin4, Dongqing Gu3, Zhengguo Wang5. 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.
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.
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.
Authors: Grace Xia Chen; Jeroen Douwes; Leonard H van den Berg; Bill Glass; David McLean; Andrea Martine 't Mannetje Journal: Acta Neurol Scand Date: 2022-03-31 Impact factor: 3.915