Standardised distributions* of several known and possible risk factors for driver injury, by indicators of socioeconomic status
| Educational level | Occupational status | Neighbourhood income | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Secondary | International Socioeconomic Index Score† | NZ$000 (in 1991) | ||||||||||
| University/polytechnic | >3 years | 2–3 years | <2 years | 60–85 | 40–59 | 30–39 | 20–29 | 40.0–69.7 | 35.0–39.9 | 27.5–34.9 | 15.0–27.4 | |
| SD, standard deviation. p Values for homogeneity of risk factors across levels of each socioeconomic indicator: all p<0.001, except for driving exposure across categories of neighbourhood income (p=0.02). | ||||||||||||
| *Percentages, means, and p values were standardised for age and sex unless stated otherwise. | ||||||||||||
| †Higher scores indicate higher occupational status. | ||||||||||||
| ‡Data on educational level missing for 340 (educational level), 1217 (occupational status) and 1147 (neighbourhood income) 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 as this variable was estimated from age and sex characteristics. | ||||||||||||
| Number of participants‡ | 3893 | 2340 | 2018 | 1934 | 2240 | 2807 | 2588 | 1673 | 2461 | 2174 | 2570 | 2173 |
| Age, mean (SD), years§ | 42.0 (14.8) | 40.2 (14.4) | 44.1 (14.4) | 55.2 (14.4) | 46.4 (15.4) | 43.3 (14.7) | 44.4 (15.4) | 39.8 (15.9) | 47.5 (15.2) | 45.7 (15.4) | 43.5 (15.6) | 41.9 (15.7) |
| Men, %¶ | 72.8 | 69.7 | 70.7 | 79.4 | 77.7 | 53.7 | 76.1 | 91.5 | 63.8 | 71.1 | 72.9 | 78.6 |
| Maximum alcohol intake, mean (SD), drinks/day | 5.4 (7.4) | 7.0 (7.3) | 7.2 (7.2) | 7.3 (7.7) | 5.6 (7.4) | 6.5 (7.1) | 6.6 (7.4) | 7.9 (7.8) | 5.7 (7.2) | 6.4 (7.3) | 6.3 (7.4) | 7.4 (7.5) |
| Total estimated driving exposure, mean (SD), 000 km** | 93.0 (22.5) | 90.6 (22.1) | 95.3 (21.9) | 90.6 (23.3) | 96.0 (22.7) | 93.2 (21.5) | 91.6 (22.6) | 90.0 (23.4) | 92.5 (21.7) | 92.9 (21.9) | 92.0 (22.1) | 90.9 (22.4) |
| Much work related driving, %¶ | 0.4 | 2.1 | 4.0 | 6.9 | NA | NA | 9.6 | 1.2 | 1.6 | 2.0 | 3.0 | 3.5 |
| Resident in rural area, % | 15.3 | 26.8 | 24.4 | 19.0 | 13.6 | 23.5 | 21.6 | 26.8 | 1.4 | 31.7 | 18.6 | 26.5 |
| Currently married/living with partner, % | 75.3 | 73.8 | 76.1 | 71.9 | 79.3 | 75.4 | 73.8 | 69.5 | 75.3 | 76.8 | 73.4 | 70.1 |
| Body mass index, mean (SD), kg/m2 | 25.3 (4.3) | 26.1 (4.2) | 26.4 (4.1) | 26.7 (4.4) | 25.6 (4.3) | 25.5 (4.1) | 26.4 (4.3) | 26.9 (4.4) | 25.3 (4.2) | 26.4 (4.2) | 26.1 (4.2) | 26.2 (4.3) |
| Workforce cohort, % | 71.4 | 80.0 | 81.0 | 75.6 | 70.4 | 77.6 | 76.4 | 81.5 | 67.0 | 73.1 | 78.7 | 84.7 |