Characteristics of smoking and secondhand smoke exposure in monozygotic and dizygotic twins: Results from an international twin study

Abstract

Introduction: Zygosity differences in smoking exposure are unclear in twins. Aims: To assess smoking and secondhand smoke exposure characteristics in twins. Methods: 151 monozygotic and 62 dizygotic Hungarian and American adult twin pairs (age 43.8±16.5 years, mean±SD) participated in the study. Results: Monozygotic twins started smoking 1.8 years earlier compared to dizygotic twins (p = 0.08). Dizygotic twins smoked longer (p<0.01) and suffered more parental smoke exposure during childhood (p<0.05). Monozygotic twins reported stricter smoking restrictions at home and workplaces (p<0.005) and less smoke exposure in indoor public places (p<0.01). 85.7% of monozygotic twins were ex or active smokers, while only 69.5% of the dizygotics (p<0.01). Lesser difference was observed in the self-reported smoke exposure rate in monozygotic compared to dizygotic pairs concerning restaurants and cafés (p<0.05) which was not present regarding bars, pubs and transportation facilities. Conclusions: Different psychological family orientation may be present across zygosity. Preventive parental care is warranted in twin families exposed to smoking. Orv. Hetil., 2012, 153, 1552–1559.