Table 3

ORs for timing and duration of passive smoking amongst nonactive smokers according to NAT2 genotype in a population-based case-control study of breast cancer in Germany, 1992–1995

Rapid acetylatorsSlow acetylators
Cases n = 82Controls n = 137OR (95% CI)aCases n = 92Controls n = 231OR (95% CI)a
Never passive (reference)14381.025751.0
Ever passive68961.98 (0.96–4.09)671561.16 (0.66–2.04)
Timing
 Only as child9151.41 (0.48–4.11)4220.49 (0.14–1.67)
 Only as adult27352.07 (0.89–4.81)28571.21 (0.62–2.38)
 As child and adult32462.18 (0.96–4.96)35771.30 (0.69–2.45)
 Missing3
Duration in childhoodb
 Passive only as adult27352.07 (0.89–4.80)28571.22 (0.62–2.39)
 1–10 years11161.78 (0.63–5.01)9181.80 (0.68–4.79)
 11+ years30451.98 (0.88–4.46)30811.00 (0.52–1.91)
 Missing3
Duration in adulthoodc
 Passive only as child9151.39 (0.48–4.07)4220.47 (0.14–1.64)
 1–10 years24342.08 (0.88–4.91)27531.59 (0.81–3.11)
 11–20 years17271.68 (0.67–4.24)15321.17 (0.52–2.63)
 21+ years18202.91 (1.12–7.59)21490.95 (0.45–2.02)
 Missing3
Passive exposure in lifetimed
 1–50 h/day yrs31441.81 (0.80–4.05)24750.92 (0.47–1.80)
 51+ h/day yrs36492.24 (1.01–4.95)43771.48 (0.79–2.79)
  • a OR (95% CI): stratified for age by five year intervals, additionally adjusted for number of full-term pregnancies as a categorical variable (0, 1–2, 3 or more full-term pregnancies), total number of months of breastfeeding and body mass index as continuous variables, average daily alcohol intake (categorized as 0, 1–18, 19+ grams per day), first degree family history, education (classified into low, intermediate, and high, according to type of schooling attained and the subsequently obtained professional degree), and for menopausal status (postmenopausal, premenopausal, and unknown).

  • b Additionally adjusting for number of years of adulthood exposure did not appreciably alter the estimates (data not shown).

  • c Additionally adjusting for number of years of childhood exposure did not appreciably alter the estimates (data not shown).

  • d Sum of hours per day-years for the sources partner, work, and childhood, whereby childhood hours per day-years were divided by number of smokers to avoid overlapping of exposures; the dichotomization is attributable to the median of nonsmoking controls.