Dietary isothiocyanates, glutathione S-transferase M1 (GSTM1), and lung cancer risk in African Americans and Caucasians from Los Angeles County, California

Nutr Cancer. 2009;61(4):492-9. doi: 10.1080/01635580902752270.

Abstract

Isothiocyanates, found in cruciferous vegetables, are anticarcinogenic. Racial differences in smoking do not fully account for the African-American excess lung cancer incidence. African Americans consume more cruciferous vegetables than U.S. Whites. Impact on lung cancer risk is unknown. The glutathione S transferase M1 (GSTM1) gene promotes urinary isothiocyanate excretion. We evaluated dietary isothiocyanates and lung cancer using a population-based case-control study of 933 African Americans and Caucasians (non-Hispanic U.S. White) from Los Angeles County, California (311 cases; 622 controls). Broccoli, cauliflower, greens, and cabbage food-frequency variables represented isothiocyanates. Isothiocyanates were protective for lung cancer risk. Adjusted odds ratio (OR) for the uppermost quartile > 80 micro mol isothiocyanates/wk, compared to lowest, was 0.65 [95% confidence interval (CI) = 0.41-1.00, trend P = 0.02]. Association was stronger among subjects with homozygous deletion of GSTM1 (OR = 0.52, 95% CI = 0.31-0.86) than subjects with at least one GSTM1 copy (OR = 0.77, 95% CI = 0.49-1.21). The difference was not statistically significant (P = 0.16). Despite African Americans consuming more cruciferous vegetables, the isothiocyanate association did not vary by race (P = 0.52). Reduced lung cancer risk with higher isothiocyanate intake may be slightly stronger among subjects with deletion of GSTM1.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • African Americans* / genetics
  • Aged
  • Aged, 80 and over
  • Aging
  • Analysis of Variance
  • Brassicaceae / chemistry
  • Case-Control Studies
  • Confidence Intervals
  • Diet Surveys
  • Diet*
  • European Continental Ancestry Group* / genetics
  • Female
  • Gene Deletion
  • Genetic Predisposition to Disease
  • Glutathione Transferase / deficiency
  • Glutathione Transferase / genetics*
  • Health Status Disparities
  • Humans
  • Isothiocyanates / administration & dosage*
  • Linear Models
  • Los Angeles / epidemiology
  • Lung Neoplasms / ethnology*
  • Lung Neoplasms / genetics
  • Lung Neoplasms / prevention & control
  • Male
  • Middle Aged
  • Polymorphism, Genetic
  • Probability
  • Risk Factors
  • Sex Characteristics
  • Smoking
  • Surveys and Questionnaires

Substances

  • Isothiocyanates
  • Glutathione Transferase
  • glutathione S-transferase M1