Alcohol consumption, variability in alcohol dehydrogenase genes and risk of renal cell carcinoma.

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.

Coffee consumption and risk of renal cell carcinoma.

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.

Evaluation of awareness of risk factors for kidney cancer among patients presenting to a urology clinic.

OBJECTIVE: This study aimed to evaluate awareness of risk factors for kidney cancer among patients presenting to a urology clinic. Smoking, obesity and hypertension are widely accepted as risk factors for kidney cancer; however, there are limited data regarding awareness of these risk factors. MATERIAL AND METHODS: The researchers prospectively identified 172 patients presenting to a urology clinic between 1 May 2009 and 31 August 2009. Each patient completed a questionnaire that requested responses to whether certain lifestyle factors increased the risk of a variety of cancers. Information on demographics and other covariates was collected via questionnaires and medical chart abstraction. To estimate and compare risk factor awareness levels for different cancers, 95% confidence intervals (95% CIs) were constructed and Fisher's exact tests performed. Logistic regression analysis was used to evaluate covariates associated with risk factor awareness. RESULTS: The percentage reporting that smoking increases the risk of kidney cancer (36%, 95% CI 29-44%) was lower than for lung cancer (96%, 95% CI 92-99%). Similarly, the percentage reporting that obesity increases the risk of kidney cancer (32%, 95% CI 25-40%) was lower than for colon cancer (45%, 95% CI 37-53% CI). Only 18% (95% CI 13-25%) identified hypertension as a risk factor for kidney cancer. Female gender and younger age were associated with increased levels of awareness of the association with smoking and obesity, respectively. CONCLUSION: The data support a low level of awareness of kidney cancer risk factors and underscore an opportunity for urologists to engage in education efforts.