Passive smoking and influenza-like illness in housewives: A perspective of gene susceptibility.

Relation between influenza-like illness (ILI) and passive smoking remains a debate of subject. We aimed to determine an association of passive smoking with ILI risk of housewives in North China, and the modification effects of gene polymorphisms related to the metabolisms of smoking pollutants. We included 379 housewives for a cross-sectional study in Shanxi Province, China, including 118 with ILI frequency of "≥1 times per year" as the case group and 261 with ILI frequency of "<1 time per year" in the past 10 years as the control group. We collected their information on frequencies of passive smoking and ILI by questionnaires, as well as their single nucleotide polymorphisms (SNPs) of genes related to Phase I and Phase II metabolisms of smoking pollutants. Our results revealed a significant Spearman correlation between frequencies of ILI and passive smoking (r = 0.406, p < 0.001). Frequency of passive smoking was associated with an increased risk of ILI with adjusted OR [6.75 (95% confidence interval: 3.98-11.4)]. Dose-response association between the passive smoking and ILI risk was observed with or without adjusting for confounders. Mutant types of rs1041983 (N-acetyltransferase 2 gene, NAT2) had a synergetic effect with passive smoking on ILI frequency, while mutant types of rs1695 (glutathione S-transferase P1 gene, GSTP1) had an antagonistic effect. Overall, our study results supported the hypothesis that passive smoking was positively associated with ILI frequency in housewives and this effect was modified by gene polymorphisms of Phase II metabolism genes (NAT2 and GSTP1).