RESUMO
Alcohol consumption has been associated inversely with renal cell carcinoma (RCC) risk; however, no study has examined effect modification by germline variation in alcohol-metabolizing genes. We investigated whether the association between alcohol intake and RCC risk is modulated by germline variants in alcohol dehydrogenase genes in a large case-control study. Data from 652 RCC cases and 1,366 non-cancer controls were analyzed. Alcohol intake was assessed using a standardized risk factor questionnaire. Three previously genotyped polymorphisms in ADH6 and ADH7 with the TaqMan assay were examined. Odds ratios (ORs) and 95% confidence interval (CI) were calculated using logistic regression, adjusting for covariates. Compared to non-drinkers, ever consumption of alcohol was associated with lower RCC risk (OR = 0.52, 95% CI = 0.42-0.65). Analysis with cubic spline regression curve showed a "J-shaped" relationship between alcohol drinks/day and RCC risk, such that there was no added benefit against RCC for consumption of more than two drinks/day. We observed effect modification by variation in rs1154454 (ADH7) (pinteraction = 0.007); a per unit increase in alcohol drink/day was associated with 35% lower RCC risk among non-minor allele carriers, a 27% lower risk among those who carry one copy of the minor allele, but no association was observed among those with two copies of the minor allele. These findings indicate that alcohol consumption is associated with lower RCC risk. Consuming more than two drinks a day does not confer additional protection against RCC. The association between alcohol intake and RCC risk appears to be modulated by inter-individual germline variation in alcohol-metabolizing genes.
Assuntos
Álcool Desidrogenase/genética , Consumo de Bebidas Alcoólicas/epidemiologia , Consumo de Bebidas Alcoólicas/genética , Carcinoma de Células Renais/epidemiologia , Carcinoma de Células Renais/genética , Neoplasias Renais/epidemiologia , Neoplasias Renais/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Consumo de Bebidas Alcoólicas/metabolismo , Carcinoma de Células Renais/enzimologia , Estudos de Casos e Controles , Feminino , Humanos , Neoplasias Renais/enzimologia , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo ÚnicoRESUMO
BACKGROUND: Studies have suggested an inverse association between coffee consumption and risk of renal cell carcinoma (RCC); however, data regarding decaffeinated coffee are limited. METHODS: We conducted a case-control study of 669 incident RCC cases and 1,001 frequency-matched controls. Participants completed identical risk factor questionnaires that solicited information about usual coffee consumption habits. The study participants were categorized as non-coffee, caffeinated coffee, decaffeinated coffee, or both caffeinated and decaffeinated coffee drinkers. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression, adjusting for multiple risk factors for RCC. RESULTS: Compared with no coffee consumption, we found an inverse association between caffeinated coffee consumption and RCC risk (OR 0.74; 95% CI 0.57-0.99), whereas we observed a trend toward increased risk of RCC for consumption of decaffeinated coffee (OR 1.47; 95% CI 0.98-2.19). Decaffeinated coffee consumption was associated also with increased risk of the clear cell RCC (ccRCC) subtype, particularly the aggressive form of ccRCC (OR 1.80; 95% CI 1.01-3.22). CONCLUSIONS: Consumption of caffeinated coffee is associated with reduced risk of RCC, while decaffeinated coffee consumption is associated with an increase in risk of aggressive ccRCC. Further inquiry is warranted in large prospective studies and should include assessment of dose-response associations.