Prevalence and predictors of third hand smoke exposure in Hong Kong: findings from a territory-wide survey in 2014

Abstract

Significance and aim Third hand smoke (THS) exposure was associated with adverse health. Most studies were conducted in Western countries. We studied the pattern and factors associated with THS exposure in Chinese adults in Hong Kong. Methods A subsample of 910 respondents (59.9% female, aged 40.1 ± 15.2 and 62.1% married)were randomly selected from 2419 adults in a telephone survey in 2014. THS exposure anywhere was measured by a question of “In the past 7 days, have you ever smelled the odor of cigarette from the air, any objects, people or self, while you did not witness any burning cigarettes nearby?”. A similar question was used for THS at home. Duration of THS exposure anywhere (hours/day) and at home (days/week)were also reported. Because of oversampling of ex- and current smokers, weighting by sex, age, and smoking prevalence according to Hong Kong Census and Thematic Household Surveywas done. Results For THS exposure anywhere, the prevalence was 37.9% (mean hours per day: 0.84 ± 1.02). Respondents aged 60-65 were less likely to be exposed (vs. aged <30; odds ratio [OR]: 0.60, 95%CI: 0.37 to 0.96). Those with secondary education were more likely (vs. primary education; OR: 1.74, 95%CI: 1.08 to 2.82) to be exposed. Having any and the number of smoking family members were associated with longer hours of exposure per day (β-coefficient [β]: 0.38, 95%CI: 0.14 to 0.63 and β: 0.21, 95%CI: 0.04 to 0.38 respectively). For THS exposure at home, the prevalencewas 16.9% (mean days per week: 4.01 ± 2.36). Currently smoking (OR: 1.89, 95%CI: 1.06 to 3.39) was associated with more THS exposure. Having household income ≥HK$30,000 (OR: 0.57, 95%CI: 0.37 to 0.87), having secondary and tertiary education (OR: 0.57, 95%CI: 0.37 to 0.87 and OR: 0.38, 95%CI: 0.23 to 0.64 respectively) and living in private housing (OR: 0.56, 95%CI: 0.41 to 0.77) were associated with less THS exposure. Having secondary and tertiary education (β: -1.90, 95%CI: -2.82 to -0.97 and β: 0.-2.41, 95%CI: -3.39 to -1.43) and living in private housing (β: -0.78, 95%CI: -1.44 to -0.12) were associated with fewer days of exposure per week. Having a smokefree home was not associatedwith any of the above THS exposure variables. Conclusions This first study on Chinese adult THS exposure showed THS exposure was prevalent. Smokers have to quit smoking completely as they would bring THS into their homes even if they smoke outside. Further studies on health impacts of THS and effective interventions to eliminate THS are warranted.