GSTP1 and asthma: The relationship between dietary antioxidant intake and ETS was more apparent in children with AA at nucleotide 1695 of the GSTP1. Children with the AA genotype who had been exposed to ETS and had low intakes of vitamin A or carotene were more likely to have an asthma diagnosis than children with no ETS exposure and high intakes of vitamin A or carotene (vitamin A: aOR, 4.44, 95 % CI, 1.58–12.52; carotene: aOR, 3.15, 95 % CI, 1.15–8.63; Additional file 2: Table S2, Figs. 1 and 2).