Table 1

Standardised distributions* of several known or possible risk factors for driver injury, by marital status

Never marriedMarriedDivorced, separated, widowedp Value for homogeneity
*Percentages, means, and p values adjusted (unless stated otherwise) for age and sex by direct standardisation to the study population (categorical variables), or by analysis of covariance (continuous variables). p Values calculated by the Mantel-Haenszel χ2 test for association (categorical variables) or analysis of covariance (continuous variables).
†Data on marital status missing for 38 participants.
‡Standardised for sex only.
§Standardised for age only (in the case of work related driving, additional standardisation for sex was not possible because of sparse data).
∥Total estimated driving exposure between 1988 and 1998; not standardised for either age or sex since this variable was estimated from age and sex.
Number of participants†148177661240
Age, mean (SD), years‡30.7 (13.9)44.9 (15.3)55.4 (13.6)<0.0001
Men, %§67.275.753.0<0.0001
Maximum alcohol intake, mean (SD), drinks/day8.4 (7.6)5.8 (7.9)7.5 (7.3)<0.0001
Total estimated driving exposure, mean (SD), 000 km∥103 (44)115 (44)76.2 (44)<0.0001
Much work related driving, %§2.92.53.00.45
Resident in rural area, %15.421.417.2<0.0001
Occupational status score, mean (SD)†43.1 (17.5)46.9 (18.3)43.7 (17.3)<0.0001
Body mass index, mean (SD), kg/m225.3 (4.5)26.2 (4.6)25.8 (4.3)<0.0001
Workforce cohort, %75.076.972.1<0.0001