Table 3

Association of adult respiratory symptoms and lung function with parental smoking in childhood

Prevalence of symptom*Paternal smokingMaternal smokingMaternal smoking in pregnancyOne parent smokingBoth parents smokingDose-response
OR (95%CI)†p valueOR (95%CI)†p valueOR (95%CI)†p valueOR (95%CI)†OR (95%CI)†p value
Wheeze23% (4308/18688)1.03 (0.94 to 1.13)0.51.12 (1.02 to 1.23)0.0161.24 (1.09 to 1.42)0.0011.02 (0.92 to 1.12)1.15 (1.02 to 1.29)0.022
>3 asthma symptoms16% (2861/18446)1.08 (0.98 to 1.20)0.11.14 (1.02 to 1.26)0.0161.28 (1.11 to 1.48)0.0011.03 (0.92 to 1.15)1.22 (1.07 to 1.39)0.004
Current asthma5% (874/18626)0.90 (0.76 to 1.06)0.21.06 (0.89 to 1.25)0.51.14 (0.89 to 1.44)0.30.86 (0.72 to 1.03)0.96 (0.77 to 1.18)0.6
Chronic bronchitis11% (1970/18638)1.12 (0.99 to 1.27)0.0821.19 (1.05 to 1.35)0.0081.32 (1.11 to 1.57)0.0021.08 (0.94 to 1.25)1.34 (1.14 to 1.57)<0.001
β coeff (95%CI)‡p valueβ coeff (95%CI)‡p valueβ coeff (95%CI)‡p valueβ coeff (95%CI)‡β coeff (95%CI)‡p value
*The number of subjects answering each question varied, thus the denominators are different.
†Odds ratios with 95% confidence intervals as estimated by logistic regression adjusting for sex, age, body mass index, number of siblings, current smoking, current environmental tobacco smoking, current occupation, and study centre.
‡Analysed with adjustment for interaction of sex with height, age, weight and weight squared, number of siblings, current smoking, current environmental tobacco smoking, current occupation, and study centre.
FEV1 (ml)−6 (−23 to 11)0.5−24 (−42 to −5)0.012−24 (−50 to 3)0.082−7 (−26 to 11)−31 (−53 to −8)0.010
FVC (ml)4 (−15 to 24)0.7−1 (−22 to 20)0.919 (−11 to 50)0.23 (−18 to 24)4 (−22 to 30)0.7
FEV1/FVC ratio (%)−0.2 (−0.4 to 0)0.094−0.5 (−0.8 to−0.3)<0.001−0.9 (−1.3 to −0.5)<0.001−0.2 (−0.4 to 0.0)−0.8 (−1.1 to −0.5)<0.001
BHR (ECRHS slope)0.00 (−0.07 to 0.08)0.90.04 (−0.5 to 0.12)0.60.01 (−0.12 to 0.14)0.90.06 (−0.03 to 0.14)0.03 (−0.08 to 0.13)0.5