Table 2

Crude and adjusted rate ratios of invasive meningococcal disease for parental smoking and socioeconomic circumstances

Crude RRAdjusted RR2-150
RR95% CIRR95% CI
Parental smoking
 Mother (Yes vNo)4.892.29–10.53.521.42–8.68
 Father (YesvNo)3.731.95––6.94
 Mother only2.010.54–7.431.000.21–4.79
 Father only1.570.70–3.531.470.55–3.95
 Both parents8.793.42––29.3
Smoking at home
 Per 20 cigarettes a day3.481.89–6.422.651.31–5.35
Mother's education
p trend <0.001p trend 0.287
Father's education
p trend 0.099p trend 0.987
Car ownership
Weekend house
 >1 person per room2.181.12––2.88
No. of siblings
p trend 0.087p trend 0.968
Spending weekends out of town
 <1 day a month1.01.0
 1–5 days a month0.430.15–1.210.940.20–4.32
 >5 days a month0.180.05–0.570.410.10–1.74
p trend 0.004p trend 0.166
  • 2-150 Each variable was adjusted for smoking, mother's and father's education, ownership of car and cottage, and crowding. Only one indicator of smoking was included in each model. Non-smoking variables were adjusted for categorical measure of parental smoking (none, mother only, father only, both).