Joint effects of household ventilation and indoor air pollutants on lung cancer risk.

aHigh-temperature cooking oil and coal used for cooking were included in kitchen ventilation, solid fuels used for heating was included in bedroom ventilation while ever smoking and secondhand smoke at home were included in both kitchen and bedroom ventilation.bAdjusted for age (continuous), gender, education level (illiterate/primary school/middle school/high school/college), income 10 years ago (Yuan/year, continuous), body mass index (kg/m2, continuous), family history of lung cancer (yes/no), pack-years of smoking (continuous), ethanol consumption (ml/week, continuous), and study area (Dafeng/Ganyu).cThe joint effects category for further estimation of additive interaction.dThe reference category for measures of interaction on additive scale.