Parental smoking and allergic sensitization in offspring defined by skin prick testing

Investigations of parental smoking during childhood and allergic sensitization have produced contradictory results, but this may be because of variations in the definition of allergy and other influences. We investigated associations of parental smoking with an objective measure of allergy, skin prick testing (SPT), and considered associations with maternal and paternal smoking, independently of each other. A stratified random sample, aged 22-74 yr, of 720 Swedish FinEsS-study members were skin prick tested for 15 allergens. Subjects with at least one positive SPT were defined as atopic. Data on childhood exposures, including parental smoking, were collected by structured interview. Logistic regression used atopy as the dependent variable. After adjustment, paternal smoking was statistically significantly associated with an increased risk and maternal smoking a non-statistically significant decreased risk in offspring, with odds ratios (and 95% confidence intervals) of 1.48 (1.04-2.10) and 0.73 (0.48-1.12), respectively. Analysis of families with a non-smoking mother produced an odds ratio for paternal smoking of 1.61 (1.09-2.37). The negative association between maternal smoking and atopy may not operate through passive smoke exposure and could conceal a significant increased risk associated with passive exposure to tobacco smoke in childhood.