Motorcycle-Related Mortality in Brazil, 2000-2023: National Trends by Region, Sex, and Age.

Background Motorcyclist mortality has increased substantially in Brazil, but its long-term trajectory and variation across population groups remain incompletely characterized. We examined national trends from 2000 through 2023 by geographic region, sex, and age group. Methods We conducted a nationwide ecological time-series study of deaths among Brazilian residents assigned to International Classification of Diseases, 10th Revision (ICD-10) codes V20-V29 in the Mortality Information System. Population denominators were obtained from the Brazilian Institute of Geography and Statistics. Crude and directly age-standardized rates were calculated using the 2022 census population as the standard. Weighted segmented log-linear regression estimated annual percentage changes (APCs) and average annual percentage changes with 95% CIs. Joinpoints were selected using a BIC-type criterion; 2020 was not prespecified. Differences in average slopes were assessed using negative binomial models with population offsets and year-by-group interactions. Results Between 2000 and 2023, 225,530 motorcyclist deaths were recorded. The age-standardized mortality rate increased from 1.40 to 6.25 per 100,000 population. Mortality increased during 2000-2006 (APC, 16.7%; 95% CI, 16.0%-17.3%), 2006-2010 (9.7%; 9.1%-10.2%), and 2010-2014 (2.9%; 2.5%-3.4%), declined during 2014-2020 (-2.3%; -2.6% to -2.0%), and increased during the 2020-2023 segment (4.9%; 4.2%-5.6%). In 2023, rates were highest in the Northeast (9.47), Central-West (8.80), and North (8.45). Men accounted for 89.2% of deaths. Adults aged 20-24 years had the highest 2023 rate and the largest absolute increase, whereas adults aged 50 years or older experienced the largest relative increases from lower baseline rates. Average log-linear slopes differed by region (Holm-adjusted p=0.0016) and age group (Holm-adjusted p<0.001). The year-by-sex interaction did not provide evidence of a difference in the average slope (Holm-adjusted p=0.30), although the segmented trajectories differed in timing. Conclusions Motorcyclist mortality increased more than fourfold, with nonlinear temporal changes and marked regional and age-related heterogeneity. Young adults bore the greatest absolute burden, whereas relative increases were largest at older ages from lower baseline rates. Population-based rates cannot distinguish changes in motorcycle exposure from changes in exposure-adjusted risk.