@misc{10481/74043,
year = {2022},
month = {2},
url = {http://hdl.handle.net/10481/74043},
abstract = {The effect of helmet use on reducing the risk of death in cyclists appears to be distorted by some
variables (potential confounders, effect modifiers, or both). Our aim was to provide evidence for or
against the hypothesis that cycling area may act as a confounder and effect modifier of the association
between helmet use and risk of death of cyclists involved in road crashes. Data were analysed for
24,605 cyclists involved in road crashes in Spain. A multiple imputation procedure was used to
mitigate the effect of missing values. We used multilevel Poisson regression with province as the group
level to estimate the crude association between helmet use and risk of death, and also three adjusted
analyses: (1) for cycling area only, (2) for the remaining variables which may act as confounders, and
(3) for all variables. Incidence–density ratios (IDR) and their 95% confidence intervals were calculated.
Crude IDR was 1.10, but stratifying by cycling area disclosed a protective, differential effect of helmet
use: IDR = 0.67 in urban areas, IDR = 0.34 on open roads. Adjusting for all variables except cycling area
yielded similar results in both strata, albeit with a smaller difference between them. Adjusting for
cycling area only yielded a strong association (IDR = 0.42), which was slightly lower in the adjusted
analysis for all variables (IDR = 0.45). Cycling area can act as a confounder and also appears to act as an
effect modifier (albeit to a lesser extent) of the risk of cyclists’ death after a crash.},
publisher = {Nature},
title = {Cycling area can be a confounder and effect modifier of the association between helmet use and cyclists’ risk of death after a crash},
doi = {10.1038/s41598-022-07135-1},
author = {Molina Soberanes, Daniel and Martínez Ruiz, Virginia Ana and Águila Gordo, Daniel and Martín de los Reyes, Luis Miguel and Rivera Izquierdo, Mario and Lardelli Claret, Pablo},
}