PHE 505 Module 4 Milestone Two Example

What We Know and What We Do Not: A Literature Review on Helmets and Head Injuries Among Shared Scooter Riders

[Student Name]

Southern New Hampshire University

PHE 505: Research Methods in Public Health

Final Project Milestone Two

[Instructor Name]

[Date]

The organization, setting and figures below are a composite written as a model document. No real employer, client, colleague or patient is described.

What We Know and What We Do Not: A Literature Review on Helmets and Head Injuries Among Shared Scooter Riders

Shared electric scooters have been studied for only a few years, and most of what is known comes from hospital records in large cities. This review brings that evidence together around the proposed question, which asks if riding bareheaded raises the chance that an injured adult rider's harm includes the head. It groups the findings into four themes, evaluates the strength of the methods and ends with the gap the proposed study would fill.

Theme 1: Injuries Are Common and Often Involve the Head

Every hospital study reviewed found head injuries among the most frequent harms. In the first systematic description, about four in ten of the 249 patients seen at two Los Angeles emergency departments had a head injury, and nearly a third had a fracture (Trivedi et al., 2019). A review across a larger hospital network found similar patterns and highlighted falls from loss of balance as the leading cause (Bloom et al., 2021). Nationally, surveillance data showed scooter injuries and admissions climbing year after year as shared fleets spread (Namiri et al., 2020). Together, these studies establish that the problem is real and growing, though the share of head injuries varies with how each study defined them.

Theme 2: Riders Seldom Wear Helmets

Helmet use is strikingly low wherever it has been measured. Among injured riders, documented use was about 4% in Los Angeles (Trivedi et al., 2019) and 3% in the hospital network studied by Bloom et al. (2021). Observing riders on the street, Trivedi and colleagues found more than nine in ten bareheaded. The contrast with cyclists is sharp: in a single Washington, DC, emergency department, 2% of injured scooter riders wore helmets against two thirds of injured cyclists (Cicchino et al., 2021). Low use probably reflects the nature of shared scooters, which are rented on impulse for short trips, rarely come with a helmet and attract casual riders.

Theme 3: What Helmets Are Known to Prevent

Direct evidence on helmets for scooter riders is thin. Bloom et al. (2021) reported that no rider with a brain injury had worn a helmet, but with only eight helmeted riders in the study, that finding cannot estimate an effect. The best available estimate comes from cyclists. Pooling 40 studies, Olivier and Creighton (2017) showed injured cyclists in helmets faring much better, with markedly lower odds of any head injury and lower still for serious ones. Whether that protection carries over is uncertain. Cicchino et al. (2021) found that scooter crashes less often involve vehicles and produce different injury patterns from bicycle crashes, including more concussions with loss of consciousness, so the size of a helmet effect could differ.

Theme 4: Other Factors That Raise Risk

Several factors appear repeatedly alongside injury. Alcohol and other substances were present in a share of injured riders in both Los Angeles and the hospital network, and Bloom and colleagues found higher costs of care when riders were impaired. Riders under 18, who are not permitted to rent scooters, made up about one in ten patients in two studies. Cicchino and colleagues found that injured scooter riders were older and more often women than injured cyclists. Time of day, experience and street conditions are mentioned but rarely measured. These factors matter for the proposed study because they may also be linked to helmet use, which would bias a simple comparison.

Weather and lighting deserve study too.

How Helmet Use Is Measured

A recurring problem across the studies is the exposure itself. Helmet use is usually taken from what a triage nurse or physician wrote, so it is recorded only when someone asks and documents the answer. If clinicians are more likely to note a helmet when a rider has a head injury, or to ask only seriously injured patients, the records could exaggerate or hide an association. No study reviewed tested how complete or accurate this documentation was. The proposed study will need to check this directly, for example by measuring how often helmet status is missing and whether missingness differs by injury type.

Strength of the Evidence

The scooter literature consists mainly of case series and record reviews. The STROBE statement sets out what observational studies should report, including how participants were selected, how exposures and outcomes were measured and how confounding was handled (von Elm et al., 2007). Measured against it, the scooter studies describe selection and outcomes clearly but rarely define how helmet use was determined, and none adjusts helmet comparisons for other factors. Their samples come from emergency departments, so riders with minor injuries who never sought care are missing. The bicycle meta-analysis is far stronger, with many studies and consistent results, but its relevance to scooters is indirect.

Summary Table

Table 1 summarizes how each source contributes to the themes.

Table 1. Sources by theme

Note. Suggestive means a pattern too small to estimate.

The Gap and the Proposed Study

The literature agrees that scooter head injuries are common and helmets rare, but no study has estimated how much helmets reduce head injury among scooter riders after accounting for alcohol, age, time of day and collision with a vehicle. Nearly all of it also comes from big cities on the coasts. The planned study would review three years of emergency records in a Midwestern university city, compare head injuries between helmeted and unhelmeted riders and adjust for the factors identified in Theme 4, reporting its methods according to STROBE. Because helmet use is rare, the review will need enough records to include a meaningful number of helmeted riders, which the methods milestone will address.

It would also report how often helmet status was missing, so readers can judge the measure for themselves.

References

Bloom, M. B., Noorzad, A., Lin, C., Little, M., Lee, E. Y., Margulies, D. R., & Torbati, S. S. (2021). Standing electric scooter injuries: Impact on a community. American Journal of Surgery, 221(1), 227-232. https://doi.org/10.1016/j.amjsurg.2020.07.020

Cicchino, J. B., Kulie, P. E., & McCarthy, M. L. (2021). Injuries related to electric scooter and bicycle use in a Washington, DC, emergency department. Traffic Injury Prevention, 22(5), 401-406. https://doi.org/10.1080/15389588.2021.1913280

Namiri, N. K., Lui, H., Tangney, T., Allen, I. E., Cohen, A. J., & Breyer, B. N. (2020). Electric scooter injuries and hospital admissions in the United States, 2014-2018. JAMA Surgery, 155(4), 357-359. https://doi.org/10.1001/jamasurg.2019.5423

Olivier, J., & Creighton, P. (2017). Bicycle injuries and helmet use: A systematic review and meta-analysis. International Journal of Epidemiology, 46(1), 278-292. https://doi.org/10.1093/ije/dyw153

Trivedi, T. K., Liu, C., Antonio, A. L. M., Wheaton, N., Kreger, V., Yap, A., Schriger, D., & Elmore, J. G. (2019). Injuries associated with standing electric scooter use. JAMA Network Open, 2(1), Article e187381. https://doi.org/10.1001/jamanetworkopen.2018.7381

von Elm, E., Altman, D. G., Egger, M., Pocock, S. J., Gøtzsche, P. C., & Vandenbroucke, J. P. (2007). The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: Guidelines for reporting observational studies. The Lancet, 370(9596), 1453-1457. https://doi.org/10.1016/S0140-6736(07)61602-X