Effective factors of improved helmet use in motorcyclists: a systematic review.

BACKGROUND: Road traffic injuries (RTI) are one of the most prominent causes of morbidity and mortality, especially among children and young adults. Motorcycle crashes constitute a significant part of RTIs. Policymakers believe that safety helmets are the single most important protection against motorcycle-related injuries. However, motorcyclists are not wearing helmets at desirable rates. This study systematically investigated factors that are positively associated with helmet usage among two-wheeled motorcycle riders. METHODS: We performed a systematic search on PubMed, Scopus, Web of Science, Embase, and Cochrane library with relevant keywords. No language, date of publication, or methodological restrictions were applied. All the articles that had evaluated the factors associated with helmet-wearing behavior and were published before December 31, 2021, were included in our study and underwent data extraction. We assessed the quality of the included articles using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist for observational studies. RESULTS: A total of 50 articles were included. Most evidence suggests that helmet usage is more common among drivers (compared to passengers), women, middle-aged adults, those with higher educations, married individuals, license holders, and helmet owners. Moreover, the helmet usage rate is higher on highways and central city roads and during mornings and weekdays. Travelers of longer distances, more frequent users, and riders of motorcycles with larger engines use safety helmets more commonly. Non-helmet-using drivers seem to have acceptable awareness of mandatory helmet laws and knowledge about their protective role against head injuries. Importantly, complaint about helmet discomfort is somehow common among helmet-using drivers. CONCLUSIONS: To enhance helmet usage, policymakers should emphasize the vulnerability of passengers and children to RTIs, and that fatal crashes occur on low-capacity roads and during cruising at low speeds. Monitoring by police should expand to late hours of the day, weekends, and lower capacity and less-trafficked roads. Aiming to enhance the acceptance of other law-abiding behaviors (e.g., wearing seat belts, riding within the speed limits, etc.), especially among youth and young adults, will enhance the prevalence of helmet-wearing behavior among motorcycle riders. Interventions should put their focus on improving the attitudes of riders regarding safety helmets, as there is acceptable knowledge of their benefits.

Granzyme B contributes to extracellular matrix remodeling and skin aging in apolipoprotein E knockout mice.

Apolipoprotein E knockout (apoE-KO) mice have been utilized for decades as a model of atherosclerosis. However, in addition to atherosclerosis, apoE-KO mice develop extensive cutaneous xanthomatosis, accelerated skin aging and frailty when fed a high fat diet. Granzyme B (GrB) is a pro-apoptotic serine protease that has recently been shown to exhibit extracellular proteolytic activity in certain pathologies. In the present study, the role of GrB in skin aging and pathology was assessed using the apoE-KO model of skin aging. Male C57BL/6 wild type and apoE-KO mice were grown for 0, 5, 15 or 30 weeks on either a high fat (21.2% fat, 0.2% cholesterol) or regular chow diet (7% fat). ApoE/GrB double knockout (DKO) mice were also generated and assessed after being fed either diet for 30 weeks. Skin was removed from the mid to lower back and examined for age-related changes such as hair loss, skin thinning and collagen remodeling and disorganization. ApoE-KO mice exhibited signs of frailty, hair graying, hair loss, skin thinning, loss of collagen density and increased skin pathologies featuring collagen remodeling and reduced decorin compared to wild type controls. These phenotypes occurred earlier and were more severe when fed a high fat diet. In addition, we also observed increased GrB expression in proximity to areas of decorin degradation and reduced collagen density in the skin of apoE-KO mice. DKO mice exhibited protection against skin thinning, ECM degradation and loss of dermal collagen density. In summary, our results provide novel insights into the effects of a high fat diet and apoE deficiency on skin aging and pathology and suggest a role for GrB in age-related skin thinning and frailty.