Differences in outcomes of mandatory motorcycle helmet legislation by country income level: A systematic review and meta-analysis

Authors

Jacob R. Lepard, Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, Alabama, United States of America.
Riccardo Spagiari, Humanitas University, Milano, Italy.
Jacquelyn Corley, Program in Global Surgery and Social Change, Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, United States of America.
Ernest J. Barthélemy, Program in Global Surgery and Social Change, Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, United States of America.
Eliana Kim, Program in Global Surgery and Social Change, Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, United States of America.
Rolvix Patterson, Program in Global Surgery and Social Change, Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, United States of America.
Sara Venturini, Aberdeen Royal Infirmary, Aberdeen, Scotland, United Kingdom.
Megan E. Still, Department of Neurosurgery, University of Florida, Gainesville, Florida, United States of America.
Yu Tung Lo, Department of Neurosurgery, National Neuroscience Institute, Singapore.
Gail Rosseau, Department of Neurosurgery, George Washington University School of Medicine and Health Sciences, Washington, DC, United States of America.
Rania A. Mekary, Computational Neuroscience Outcomes Center, Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America.
Kee B. Park, Program in Global Surgery and Social Change, Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, United States of America.

Document Type

Article

Abstract

BACKGROUND: The recent Lancet Commission on Legal Determinants of Global Health argues that governance can provide the framework for achieving sustainable development goals. Even though over 90% of fatal road traffic injuries occur in low- and middle-income countries (LMICs) primarily affecting motorcyclists, the utility of helmet laws outside of high-income settings has not been well characterized. We sought to evaluate the differences in outcomes of mandatory motorcycle helmet legislation and determine whether these varied across country income levels. METHODS AND FINDINGS: A systematic review and meta-analysis were completed using the PRISMA checklist. A search for relevant articles was conducted using the PubMed, Embase, and Web of Science databases from January 1, 1990 to August 8, 2021. Studies were included if they evaluated helmet usage, mortality from motorcycle crash, or traumatic brain injury (TBI) incidence, with and without enactment of a mandatory helmet law as the intervention. The Newcastle-Ottawa Scale (NOS) was used to rate study quality and funnel plots, and Begg's and Egger's tests were used to assess for small study bias. Pooled odds ratios (ORs) and their 95% confidence intervals (CIs) were stratified by high-income countries (HICs) versus LMICs using the random-effects model. Twenty-five articles were included in the final analysis encompassing a total study population of 31,949,418 people. There were 17 retrospective cohort studies, 2 prospective cohort studies, 1 case-control study, and 5 pre-post design studies. There were 16 studies from HICs and 9 from LMICs. The median NOS score was 6 with a range of 4 to 9. All studies demonstrated higher odds of helmet usage after implementation of helmet law; however, the results were statistically significantly greater in HICs (OR: 53.5; 95% CI: 28.4; 100.7) than in LMICs (OR: 4.82; 95% CI: 3.58; 6.49), p-value comparing both strata < 0.0001. There were significantly lower odds of motorcycle fatalities after enactment of helmet legislation (OR: 0.71; 95% CI: 0.61; 0.83) with no significant difference by income classification, p-value: 0.27. Odds of TBI were statistically significantly lower in HICs (OR: 0.61, 95% CI 0.54 to 0.69) than in LMICs (0.79, 95% CI 0.72 to 0.86) after enactment of law (p-value: 0.0001). Limitations of this study include variability in the methodologies and data sources in the studies included in the meta-analysis as well as the lack of available literature from the lowest income countries or from the African WHO region, in which helmet laws are least commonly present. CONCLUSIONS: In this study, we observed that mandatory helmet laws had substantial public health benefits in all income contexts, but some outcomes were diminished in LMIC settings where additional measures such as public education and law enforcement might play critical roles.

Medical Subject Headings

Accidents, Traffic (legislation & jurisprudence, mortality, prevention & control); Craniocerebral Trauma (etiology, mortality, prevention & control); Developing Countries (economics); Global Health (economics, legislation & jurisprudence); Head Protective Devices; Humans; Income; Law Enforcement; Motorcycles (legislation & jurisprudence); Policy Making; Protective Factors; Risk Assessment; Risk Factors

Publication Date

9-1-2021

Publication Title

PLoS medicine

E-ISSN

1549-1676

Volume

18

Issue

9

First Page

e1003795

PubMed ID

34534215

Digital Object Identifier (DOI)

10.1371/journal.pmed.1003795

Recommended Citation

Lepard, Jacob R.; Spagiari, Riccardo; Corley, Jacquelyn; Barthélemy, Ernest J.; Kim, Eliana; Patterson, Rolvix; Venturini, Sara; Still, Megan E.; Lo, Yu Tung; Rosseau, Gail; Mekary, Rania A.; and Park, Kee B., "Differences in outcomes of mandatory motorcycle helmet legislation by country income level: A systematic review and meta-analysis" (2021). Neurosurgery. 1735.
https://scholar.barrowneuro.org/neurosurgery/1735