Although the relation between red and processed meat intake and colorectal cancer has been reported in several epidemiologic studies, very few investigated the potential mechanisms. This study examined multiple potential mechanisms in a large U.S. prospective cohort with a detailed questionnaire on meat type and meat cooking methods linked to databases for estimating intake of mutagens formed in meats cooked at high temperatures (heterocyclic amines, polycyclic aromatic hydrocarbons), heme iron, nitrate, and nitrite. During 7 years of follow-up, 2,719 colorectal cancer cases were ascertained from a cohort of 300,948 men and women. The hazard ratios (HR) and 95% confidence intervals (95% CI) comparing the fifth to the first quintile for both red (HR, 1.24; 95% CI, 1.09-1.42; P trend < 0.001) and processed meat (HR, 1.16; 95% CI, 1.01-1.32; P trend = 0.017) intakes indicated an elevated risk for colorectal cancer. The potential mechanisms for this relation include heme iron (HR, 1.13; 95% CI, 0.99-1.29; P trend = 0.022), nitrate from processed meats (HR, 1.16; 95% CI, 1.02-1.32; P trend = 0.001), and heterocyclic amine intake [HR, 1.19; 95% CI, 1.05-1.34; P trend < 0.001 for 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and HR, 1.17; 95% CI, 1.05-1.29; P trend <0.001 for 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx)]. In general, the elevated risks were higher for rectal cancer than for colon cancer, with the exception of MeIQx and DiMeIQx, which were only associated with colon cancer. In conclusion, we found a positive association for red and processed meat intake and colorectal cancer; heme iron, nitrate/nitrite, and heterocyclic amines from meat may explain these associations.

In an attempt to understand and cope with their diagnosis, individuals with cancer may develop beliefs about the cause of their illness and these causal attributions may impact psychosocial adjustment. Connecticut participants (n=775) from the American Cancer Society's Study of Cancer Survivors-I completed a self-administered questionnaire assessing beliefs of the cause of their cancer and if they had contemplated the question "why me?" regarding their diagnosis. Written causal belief responses were coded into thematic categories and defined as either in (modifiable) or out (fixed) of an individual's control. Using logistic regression, we examined associations between sociodemographic, clinical, and psychosocial measures and identifying modifiable causal attributions, as well as contemplating "why me." Most cancer survivors (78.2%) identified one or more causes. Lifestyle and biological factors were most common, whereas psychological factors were least common, with some variation by cancer type. After multivariate adjustment, only cancer type was associated with identifying modifiable causes. Participants who contemplated "why me" (47.5%) were more likely to be younger and reported a greater number of cancer-related problems. In conclusion, the majority of cancer survivors reported specific causal attributions and many had contemplated "why me." Understanding and assessing causal attributions and more general existential questions regarding diagnsis could aid in our understanding of survivor's adjustment and psychosocial well-being. Additional research in large populations is also needed to determine if other characteristics are associated with identifying modifiable causal attributions and asking "why me".

BACKGROUND: Meat could be involved in bladder carcinogenesis via multiple potentially carcinogenic meat-related compounds related to cooking and processing, including nitrate, nitrite, heterocyclic amines (HCAs), and polycyclic aromatic hydrocarbons (PAHs). The authors comprehensively investigated the association between meat and meat components and bladder cancer. METHODS: During 7 years of follow-up, 854 transitional cell bladder-cancer cases were identified among 300,933 men and women who had completed a validated food-frequency questionnaire in the large prospective NIH-AARP Diet and Health Study. The authors estimated intake of nitrate and nitrite from processed meat and HCAs and PAHs from cooked meat by using quantitative databases of measured values. Total dietary nitrate and nitrite were calculated based on literature values. RESULTS: The hazard ratios (HR) and 95% confidence intervals (CI) for red meat (HR for fifth quintile compared with first quintile, 1.22; 95% CI, 0.96-1.54; P trend ¼ .07) and the HCA 2-amino-1 methyl-6-phenylimidazo(4,5-b)pyridine (PhIP) (HR, 1.19; 95% CI, 0.95-1.48; P trend ¼ .06) conferred a borderline statistically significant increased risk of bladder cancer. Positive associations were observed in the top quintile for total dietary nitrite (HR, 1.28; 95% CI, 1.02-1.61; P trend ¼ .06) and nitrate plus nitrite intake from processed meat (HR, 1.29; 95% CI, 1.00-1.67; P trend ¼ .11). CONCLUSIONS: These findings provided modest support for an increased risk of bladder cancer with total dietary nitrite and nitrate plus nitrite from processed meat. Results also suggested a positive association between red meat and PhIP and bladder carcinogenesis. Cancer 2010;116:4345-53.