Andrew Flood

Index-based Dietary Patterns and Risk of Colorectal Cancer The NIH-AARP Diet and Health Study

The authors compared how four indexes-the Healthy Eating Index-2005, Alternate Healthy Eating Index, Mediterranean Diet Score, and Recommended Food Score-are associated with colorectal cancer in the National Institutes of Health-AARP Diet and Health Study (n = 492,382). To calculate each score, they merged data from a 124-item food frequency questionnaire completed at study entry (1995-1996) with the MyPyramid Equivalents Database (version 1.0). Other variables included energy, nutrients, multivitamins, and alcohol. Models were stratified by sex and adjusted for age, ethnicity, education, body mass index, smoking, physical activity, and menopausal hormone therapy (in women). During 5 years of follow-up, 3,110 incident colorectal cancer cases were ascertained. Although the indexes differ in design, a similarly decreased risk of colorectal cancer was observed across all indexes for men when comparing the highest scores with the lowest: Healthy Eating Index-2005 (relative risk (RR) = 0.72, 95% confidence interval (CI): 0.62, 0.83); Alternate Healthy Eating Index (RR = 0.70, 95% CI: 0.61, 0.81); Mediterranean Diet Score (RR = 0.72, 95% CI: 0.63, 0.83); and Recommended Food Score (RR = 0.75, 95% CI: 0.65, 0.87). For women, a significantly decreased risk was found with the Healthy Eating Index-2005, although Alternate Healthy Eating Index results were similar. Index-based dietary patterns that are consistent with given dietary guidelines are associated with reduced risk.

Comparing 3 Dietary Pattern Methods—Cluster Analysis, Factor Analysis, and Index Analysis—With Colorectal Cancer Risk The NIH–AARP Diet and Health Study

The authors compared dietary pattern methods-cluster analysis, factor analysis, and index analysis-with colorectal cancer risk in the National Institutes of Health (NIH)-AARP Diet and Health Study (n = 492,306). Data from a 124-item food frequency questionnaire (1995-1996) were used to identify 4 clusters for men (3 clusters for women), 3 factors, and 4 indexes. Comparisons were made with adjusted relative risks and 95% confidence intervals, distributions of individuals in clusters by quintile of factor and index scores, and health behavior characteristics. During 5 years of follow-up through 2000, 3,110 colorectal cancer cases were ascertained. In men, the vegetables and fruits cluster, the fruits and vegetables factor, the fat-reduced/diet foods factor, and all indexes were associated with reduced risk; the meat and potatoes factor was associated with increased risk. In women, reduced risk was found with the Healthy Eating Index-2005 and increased risk with the meat and potatoes factor. For men, beneficial health characteristics were seen with all fruit/vegetable patterns, diet foods patterns, and indexes, while poorer health characteristics were found with meat patterns. For women, findings were similar except that poorer health characteristics were seen with diet foods patterns. Similarities were found across methods, suggesting basic qualities of healthy diets. Nonetheless, findings vary because each method answers a different question.

Multiple Sociodemographic and Socioenvironmental Characteristics Are Correlated with Major Patterns of Dietary Intake in Adolescents

BACKGROUND Few studies have used dietary pattern analysis, a useful method to summarize dietary intake, in adolescents. OBJECTIVE Examine sociodemographic and socioenvironmental correlates of habitual dietary patterns. DESIGN Data for this cross-sectional/prospective analysis were drawn from Project EAT (Eating Among Teens), a population-based study. SUBJECTS/SETTING Project EAT-I (Time 1), collected data on 4,746 adolescents in 1998-1999. Project EAT-II (Time 2) resurveyed 53% (n=2,516) of the original cohort 5 years later in 2003-2004. Dietary intake was assessed using the Youth/Adolescent Food Frequency Questionnaire. MAIN OUTCOME MEASURES/STATISTICAL ANALYSIS PERFORMED: Factor analysis identified four dietary patterns at Time 1 (vegetable, fruit, starchy food, and snack food) and Time 2 (vegetable and fruit, fast food, starchy food, and snack food). Linear regression was used to examine the relationship of Time 1 socioeconomic status and race (mutually adjusted) on factor scores for each dietary pattern, and then of Time 1 socioenvironmental characteristics (adjusted for socioeconomic status and race) on these factor scores. RESULTS In prospective analyses, socioeconomic status, family meal frequency, and home availability of healthy food were positively associated with the vegetable and fruit and starchy food patterns and inversely associated with the fast food pattern. Home availability of unhealthy food was inversely associated with the vegetable and fruit and starchy food patterns and positively associated with the fast food and snack food patterns. Maternal, paternal, and peer support for healthy eating were positively associated with the vegetable and fruit pattern and inversely associated with the fast food pattern. Similar associations were seen in cross-sectional analyses. CONCLUSIONS Multiple correlates of dietary patterns were identified. Health professionals should target these factors to improve the dietary quality of habitual eating practices in adolescents by encouraging parents to decrease home availability of unhealthy food while increasing availability of healthy food, family meal frequency, and parental support for healthy eating.

Genomic Methylation of Leukocyte DNA in Relation to Colorectal Adenoma Among Asymptomatic Women

BACKGROUND & AIMS Systemic inhibition of DNA methylation causes cancers in animals, in part by inducing genetic instability. Epidemiologic evidence linking low genomic methylation in systemic blood DNA to carcinogenesis is limited, however, specifically to the colorectum, in which genetic instability is a primary etiologic factor. We examined genomic methylation of leukocyte DNA in relation to colorectal adenoma (CRA) among asymptomatic women (40-79 years of age) participating in a multicenter colonoscopy screening study (CONCeRN Study, 2000-2002). METHODS Of all participants who completed self-administered risk factor and food frequency questionnaires, peripheral blood donation, and colonoscopy, 115 pairs of CRA cases and controls with matching age and month of blood draw were studied. Genomic methylation of leukocyte DNA was determined by liquid chromatography mass spectrometry. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI). RESULTS Compared with women in the lowest tertile of genomic methylation, women in the second (OR, 0.72; 95% CI: 0.34-1.52) and third tertiles (OR, 0.17; 95% CI: 0.06-0.49) had lower risk of CRA (P trend = .002). The inverse relationship was stronger for nonadvanced than for advanced adenoma and, less notably, for proximal than for distal adenoma. The association was also moderately more protective with low rather than high total folate intake but did not differ by other nutrients involved in 1-carbon metabolism or colorectal cancer risk factors. CONCLUSIONS Our findings regarding asymptomatic CRA implicate systemic genomic methylation as a potential etiologic factor for an early stage of CRA.

Intakes of Fruit, Vegetables, and Carotenoids and Renal Cell Cancer Risk: A Pooled Analysis of 13 Prospective Studies

Fruit and vegetable consumption has been hypothesized to reduce the risk of renal cell cancer. We conducted a pooled analysis of 13 prospective studies, including 1,478 incident cases of renal cell cancer (709 women and 769 men) among 530,469 women and 244,483 men followed for up to 7 to 20 years. Participants completed a validated food-frequency questionnaire at baseline. Using the primary data from each study, the study-specific relative risks (RR) were calculated using the Cox proportional hazards model and then pooled using a random effects model. We found that fruit and vegetable consumption was associated with a reduced risk of renal cell cancer. Compared with <200 g/d of fruit and vegetable intake, the pooled multivariate RR for ≥600 g/d was 0.68 [95% confidence interval (95% CI) = 0.54-0.87; P for between-studies heterogeneity = 0.86; P for trend = 0.001]. Compared with <100 g/d, the pooled multivariate RRs (95% CI) for ≥400 g/d were 0.79 (0.63-0.99; P for trend = 0.03) for total fruit and 0.72 (0.48-1.08; P for trend = 0.07) for total vegetables. For specific carotenoids, the pooled multivariate RRs (95% CIs) comparing the highest and lowest quintiles were 0.87 (0.73-1.03) for α-carotene, 0.82 (0.69-0.98) for β-carotene, 0.86 (0.73-1.01) for β-cryptoxanthin, 0.82 (0.64-1.06) for lutein/zeaxanthin, and 1.13 (0.95-1.34) for lycopene. In conclusion, increasing fruit and vegetable consumption is associated with decreasing risk of renal cell cancer; carotenoids present in fruit and vegetables may partly contribute to this protection. (Cancer Epidemiol Biomarkers Prev 2009;18(6):1730–9)

Risk of Colon Cancer and Coffee, Tea, and Sugar-Sweetened Soft Drink Intake: Pooled Analysis of Prospective Cohort Studies

BACKGROUND The relationships between coffee, tea, and sugar-sweetened carbonated soft drink consumption and colon cancer risk remain unresolved. METHODS We investigated prospectively the association between coffee, tea, and sugar-sweetened carbonated soft drink consumption and colon cancer risk in a pooled analysis of primary data from 13 cohort studies. Among 731 441 participants followed for up to 6-20 years, 5604 incident colon cancer case patients were identified. Study-specific relative risks (RRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models and then pooled using a random-effects model. All statistical tests were two-sided. RESULTS Compared with nonconsumers, the pooled multivariable relative risks were 1.07 (95% CI = 0.89 to 1.30, P(trend) = .68) for coffee consumption greater than 1400 g/d (about six 8-oz cups) and 1.28 (95% CI = 1.02 to 1.61, P(trend) = .01) for tea consumption greater than 900 g/d (about four 8-oz cups). For sugar-sweetened carbonated soft drink consumption, the pooled multivariable relative risk comparing consumption greater than 550 g/d (about 18 oz) to nonconsumers was 0.94 (95% CI = 0.66 to 1.32, P(trend) = .91). No statistically significant between-studies heterogeneity was observed for the highest category of each beverage consumed (P > .20). The observed associations did not differ by sex, smoking status, alcohol consumption, body mass index, physical activity, or tumor site (P > .05). CONCLUSIONS Drinking coffee or sugar-sweetened carbonated soft drinks was not associated with colon cancer risk. However, a modest positive association with higher tea consumption is possible and requires further study.

Menopausal Hormone Therapy and Risk of Colorectal Cancer

We evaluated colorectal cancer risk associated with the duration and recency of specific menopausal hormone therapy formulations (i.e., unopposed estrogen versus estrogen plus progestin) and regimens (i.e., sequential versus continuous estrogen plus progestin use) among 56,733 postmenopausal women participating in the Breast Cancer Detection Demonstration Project follow-up study. Hormone therapy use and other risk factors were ascertained through telephone interviews and mailed questionnaires from 1979 to 1998. The final cancer group included 960 women who were identified from self-report, medical records, state registry data, and the National Death Index. Poisson regression was used to generate multivariable rate ratios (RR) and 95% confidence intervals (95% CI). We observed a decreased risk of colorectal cancer among ever users of unopposed estrogen therapy (RR, 0.83; 95% CI, 0.70-0.99). Among estrogen users, the largest reduced risk was observed for current users (RR, 0.75; 95% CI, 0.54-1.05) and users of ≥ten years duration (RR, 0.74; 95% CI, 0.56-0.96). We found a reduced risk among users of estrogen plus progestin therapy (RR, 0.78; 95% CI, 0.60-1.02), with sequential regimen users (progestin <15 days per cycle) having the largest risk reduction (RR, 0.64; 95% CI, 0.43-0.95). Past users of ≥5 years ago (RR, 0.55; 95% CI, 0.32-0.98) had the largest risk reduction. In this study, estrogen plus progestin use, especially sequential regimen use, was associated with the largest overall reduction of colorectal cancer risk. (Cancer Epidemiol Biomarkers Prev 2009;18(1):196–203)

Major Patterns of Dietary Intake in Adolescents and Their Stability over Time

A diet-patterns approach has often been used to describe eating patterns in adults but has rarely been used in adolescents. We used principal components factor analysis to: 1) describe the dietary patterns of a cohort of ethnically diverse youth during early and middle adolescence; 2) examine if the patterns persisted 5 y later; and 3) study secular trends. Project EAT-I (Time 1) collected data on 4746 middle school (younger cohort) and high school (older cohort) students in 31 Minnesota schools in 1998-1999. Project EAT-II (Time 2) resurveyed 53% (n = 2516) of the original cohort in 2003-2004. Dietary intake was assessed at Time 1 and 2 using the Youth/Adolescent FFQ. We identified dietary patterns separately by cohort (older/younger) and gender (boys/girls). At Time 1, we identified 4 patterns in early and middle adolescents that were relatively consistent between boys and girls that we labeled vegetable, fruit, sweet/salty snack food, and starchy food. Longitudinal analyses indicated that patterns were relatively stable over 5 y, with the exception of a new fast food pattern. Examination of age-matched secular trends in middle adolescents (older cohort at Time 1, younger cohort at Time 2) showed similar patterns, with the exception of the fast food pattern that emerged at Time 2 among middle adolescent boys. We identified dietary patterns in this adolescent population that differed from those usually found in adults. Patterns were similar across gender and age cohorts and were relatively similar over time, with the exception a new fast food pattern.

Dietary Glycemic Index, Glycemic Load, and Risk of Cancer: A Prospective Cohort Study

Previous studies have provided limited evidence for a harmful effect of high glycemic index and dietary glycemic load on cancer. The authors analyzed associations among glycemic index, glycemic load, and risk of cancer in women and men in the National Institutes of Health-AARP Diet and Health Study. Published glycemic index values were assigned to 225 foods/food groups. Glycemic load was calculated by multiplying the glycemic index, carbohydrate content, and intake frequency of individual foods reported on a food frequency questionnaire. From 1995 through 2003, the authors identified 15,215 and 33,203 cancer cases in women and men, respectively. Cox proportional hazards models were used to estimate multivariate relative risks and 95% confidence intervals. For women and men, respectively, the relative risks for total cancer for high versus low glycemic index were 1.03 (P(trend)=0.217) and 1.04 (P(trend)=0.012) and, for glycemic load, were 0.90 (P(trend)=0.024) and 0.93 (P(trend)=0.01). Associations with total cancer held only among the overweight for glycemic index and among those of healthy weight for glycemic load. These findings suggest that glycemic index and glycemic load are not strong predictors of cancer incidence. The direction and small magnitude of associations might be explained by the manner in which high glycemic index and glycemic load track with overall diet and lifestyle patterns.

Survival of Women with Colon Cancer in Relation to Precancer Anthropometric Characteristics: the Iowa Women's Health Study

Background: We hypothesized that precancer anthropometric variables are associated with mortality among women who developed colon cancer in a prospective cohort, the Iowa Womens Health Study (IWHS). Methods: From 1986 to 2005, 1,096 incident cases of colon cancer were identified (mean age at diagnosis, 73 years). Anthropometric characteristics were self-measured before colon cancer diagnosis (in 1986). Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI) for all-cause and colon-cancer mortality, adjusted for age at cancer diagnosis, stage, education, smoking status, and pack-years of smoking. Results: During the follow-up of up to 20 years, 493 women died; 289 had colon cancer as the underlying cause. The HRs of all-cause death were increased for the highest versus lowest tertile for weight (HR, 1.39; 95% CI, 1.10-1.76; P trend = 0.005); waist to hip ratio (WHR; HR, 1.36; 95% CI, 1.08-1.72; P trend = 0.008), and waist (HR, 1.45; 95% CI, 1.15-1.82; P trend = 0.001). Compared with that for body mass index (BMI) of 18.5 to 24.9 kg/m2, HRs were increased for BMI ≥30 kg/m2 (HR, 1.45; 95% CI, 1.14-1.85) and for the few women with BMI <18.5 kg/m2 (HR, 1.89; 95% CI, 1.01-3.53). Colon cancer mortality was positively associated with WHR and waist: HR, 1.37 (95% CI, 1.02;1.85; P trend = 0.04) and 1.34 (95% CI, 1.01-1.80; P trend = 0.05), respectively, for the highest versus lowest tertile. Conclusion: Greater precancer anthropometric measures and BMI <18.5 kg/m2 predicted poorer survival among colon cancer patients. Higher abdominal adiposity measured by WHR and waist was associated with increased risk of colon cancer death. Impact: Prediagnostic obesity may be a modifiable risk factor for death in colon cancer patients. Cancer Epidemiol Biomarkers Prev; 19(9); 2229–37. ©2010 AACR.