Kathryn Hughes Barry

Association of alcohol intake over the lifetime with colorectal adenoma and colorectal cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

Abstract Background Alcohol drinking is associated with higher colorectal cancer (CRC) risk, but research on lifetime alcohol drinking is limited. The objective of the current study was to estimate the association of lifetime alcohol drinking with incident colorectal adenoma and cancer. Methods US adults enrolled in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial reported alcohol intake during four age periods. Average lifetime alcohol intake was calculated as average drinks per week from age 18 years until study baseline. Alcohol intake patterns were defined by past and current drinking frequency. Among 12,327 participants with a negative baseline screen, 812 had an adenoma on the second screen. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for incident adenoma. During 20 years of follow‐up, 1679 incident CRC cases occurred among 88,092 participants. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% CIs for CRC. Results Current drinkers with an average lifetime alcohol intake of 14 or more drinks per week, compared with one drink or less per week, had a higher risk of CRC (HR, 1.25; 95% CI, 1.01–1.53), especially rectal cancer (HR, 1.95; 95% CI, 1.17–3.28). Consistent heavy drinking versus light drinking was positively associated with CRC risk (HR, 1.91; 95% CI, 1.17–3.12). Compared with current drinkers averaging less than one drink per week, former drinkers had lower odds of nonadvanced adenoma (OR, 0.58; 95% CI, 0.39–0.84). Current drinkers averaging from seven to less than 14 drinks compared with less than one drink per week had a lower risk of CRC (HR, 0.79; 95% CI, 0.64–0.97), especially distal colon cancer (HR, 0.64; 95% CI, 0.42–1.00). Conclusions Consistent heavy alcohol intake and higher average lifetime alcohol drinking may increase CRC risk, whereas cessation may lower adenoma risk. Associations may differ by tumor site.

Weight Change and Incident Distal Colorectal Adenoma Risk in the PLCO Cancer Screening Trial

Abstract Background Although obesity is a known risk factor, the impact of weight change on colorectal adenoma risk is less clear and could have important implications in disease prevention. We prospectively evaluated weight change in adulthood and incident colorectal adenoma. Methods We assessed weight change during early-late (age 20 years to baseline, ie, ages 55-74 years), early-middle (20-50 years), and middle-late (50 years-baseline) adulthood using self-reported weight data in relation to incident distal adenoma in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (cases = 1053; controls = 16 576). For each period, we defined stable weight as greater than −0.5 kg to less than or equal to 1 kg/5 years, weight loss as less than or equal to −0.5 kg/5 years, and weight gain as greater than 1-2, greater than 2-3, or greater than 3 kg/5 years. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) using logistic regression; all tests were 2-sided. Results Compared with stable weight, weight loss during early-late adulthood was associated with reduced adenoma risk (OR = 0.54, 95% CI = 0.34 to 0.86), particularly among those who were overweight or obese at age 20 years (OR = 0.39, 95% CI = 0.18 to 0.84). Results were similar for early-middle adulthood but less pronounced for middle-late adulthood. Weight gain greater than 3 kg/5 years during early-late adulthood was associated with increased risk (OR = 1.30, 95% CI = 1.07 to 1.58, Ptrend < .001). Findings appeared stronger among men (OR for >3 kg/5 years = 1.41, 95% CI = 1.11 to 1.80) than women (OR = 1.09, 95% CI = 0.79 to 1.50, Pinteraction = .21). Conclusions Weight loss in adulthood was associated with reduced adenoma risk, particularly for those who were overweight or obese, whereas weight gain greater than 3 kg/5 years increased risk. Findings underscore the importance of healthy weight maintenance throughout adulthood in preventing colorectal adenoma.