GSTT1 genotype modifies the association between cruciferous vegetable intake and the risk of myocardial infarction.
BACKGROUND
Cruciferous vegetables are a major dietary source of isothiocyanates that may protect against coronary heart disease. Isothiocyanates induce glutathione S-transferases (GSTs), polymorphic genes that code for enzymes that conjugate isothiocyanates, as well as mutagens and reactive oxygen species, to make them more readily excretable.


OBJECTIVE
The objective of the study was to determine whether GST genotypes modify the association between cruciferous vegetable intake and the risk of myocardial infarction (MI).


METHODS
Cases (n = 2042) with a first acute nonfatal MI and population-based controls (n = 2042) living in Costa Rica, who were matched for age, sex, and area of residence, were genotyped for a deletion polymorphism in GSTM1 and GSTT1 and an Ile105Val substitution in GSTP1. Cruciferous vegetable intake and smoking status were determined by questionnaire. Odds ratios (ORs) and 95% CIs for MI were estimated by unconditional logistic regression.


RESULTS
Compared with the lowest tertile of cruciferous vegetable intake, the highest tertile was associated with a lower risk of MI among persons with the functional GSTT1*1 allele (OR: 0.70; 95% CI: 0.58, 0.84) but not among those with the GSTT1*0*0 genotype (OR: 1.23; 95% CI: 0.83, 1.82) (P = 0.006 for interaction). This protective effect among those with the GSTT1*1 allele was greater for current smokers (OR: 0.54; 95% CI: 0.36, 0.79) than for nonsmokers. GSTP1 and GSTM1 did not modify the association between cruciferous vegetable intake and MI.


CONCLUSIONS
Consumption of cruciferous vegetables was associated with a lower risk of MI among those with a functional GSTT1*1 allele, which suggests that compounds that are detoxified by this enzyme contribute to the risk of MI.
Cornelis
Marilyn C
MC
Department of Nutritional Sciences, University of Toronto, Canada.
El-Sohemy
Ahmed
A
Campos
Hannia
H
D001937:Brassica; D016022:Case-Control Studies; D004032:Diet; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D005982:Glutathione Transferase / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D017879:Isothiocyanates / Q000378:metabolism*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000201:enzymology / Q000235:genetics*; D054647:Nutrigenomics; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D012307:Risk Factors; D012907:Smoking; D014675:Vegetables