The role of exposure on differences in driver death rates by gender and age: Results of a quasi-induced method on crash data in Spain.
OBJECTIVE
Part of the differences by age and gender in driver death rates from traffic injuries depends on the amount of exposure (km/year travelled). Unfortunately, direct indicators of exposure are not available in many countries. Our aim was to compare the age and gender differences in death rates with and without adjustment by exposure using a quasi-induced exposure approach in Spain, during 2004-2012.


METHODS
Crude and adjusted death rate ratios (CDRR and ADRR, respectively) were calculated for each age and gender group. To obtain the latter estimates, in accordance with quasi-exposure reasoning, the number of registered drivers was replaced by the number of non-infractor drivers, passively involved in collisions with another vehicle whose driver committed an infraction. 18-29 years and female drivers were chosen as the reference categories for age and gender.


RESULTS
Striking differences were found between CDRR and ADRR estimates. When CDRR were estimated, we found the highest traffic mortality among the youngest drivers, except for females in non-urban roads. ADRR however showed the highest mortality among the oldest groups, especially in females, peaking among drivers >74 years in all types of roads. Regarding differences by gender, both estimates revealed higher traffic mortality in males, although the differences were much smaller when using ADRR. CDRR and ADRR for males tended to converge as age increased.


CONCLUSIONS
Death risk from traffic injuries among drivers is clearly influenced by the amount of exposure. These findings further emphasize the need to obtain direct traffic exposure estimates by subgroups of drivers.
Escuela Nacional de Sanidad, Instituto de Salud Carlos III, c/Monforte de Lemos, 3-5, Pabellón 7, 28029 Madrid, Spain; CIBER Epidemiología y Salud Pública (CIBERESP), Avenida Monforte de Lemos, 3-5, Pabellón 11, 28029 Madrid, Spain.
José
J
Pulido
Escuela Nacional de Sanidad, Instituto de Salud Carlos III, c/Monforte de Lemos, 3-5, Pabellón 7, 28029 Madrid, Spain. Electronic address: gbarrio@isciii.es.
Gregorio
G
Barrio
CIBER Epidemiología y Salud Pública (CIBERESP), Avenida Monforte de Lemos, 3-5, Pabellón 11, 28029 Madrid, Spain.
Juan
J
Hoyos
CIBER Epidemiología y Salud Pública (CIBERESP), Avenida Monforte de Lemos, 3-5, Pabellón 11, 28029 Madrid, Spain; Departamento de Medicina Preventiva y Salud Pública, Facultad de Medicina, Universidad de Granada, Avenida de Madrid, 11, 18012, Granada, Spain; Instituto de Investigación Biosanitaria de Granada, C/Doctor Azpitarte 4 4a Planta, Edificio Licinio de la Fuente, 18012 Granada, Spain.
Eladio
E
Jiménez-Mejías
Servicio de Medicina Preventiva, Complejo Hospitalario Universitario Insular-Materno Infantil, Avenida Marítima, s/n, 35016 Las Palmas, Spain.
María Del Mar
Mdel M
Martín-Rodríguez
SWOV, Institute for Road Safety Research, Bezuidenhoutseweg 62, The Hague 2594 AW, The Netherlands.
Sjoerd
S
Houwing
CIBER Epidemiología y Salud Pública (CIBERESP), Avenida Monforte de Lemos, 3-5, Pabellón 11, 28029 Madrid, Spain; Departamento de Medicina Preventiva y Salud Pública, Facultad de Medicina, Universidad de Granada, Avenida de Madrid, 11, 18012, Granada, Spain; Instituto de Investigación Biosanitaria de Granada, C/Doctor Azpitarte 4 4a Planta, Edificio Licinio de la Fuente, 18012 Granada, Spain.
Pablo
P
Lardelli-Claret
D000063:Accidents, Traffic / Q000401:mortality* / Q000706:statistics & numerical data; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001334:Automobile Driving / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012737:Sex Factors; D013030:Spain / Q000453:epidemiology; D014195:Travel / Q000706:statistics & numerical data*; D055815:Young Adult
Age factors; Mortality; Quasi-induced exposure; Sex factors; Spain; Traffic accidents