Background Colonoscopy may be less efficacious in reducing colorectal cancer mortality in the proximal compared with the distal colon. A greater likelihood for missed and recurrent adenomas in the ...proximal colon may contribute to this phenomenon. Objective To examine whether a proximal adenoma is associated with the risk and location of missed and recurrent adenomas. Design Prospective. Setting Polyp Prevention Trial. Participants A total of 1864 patients with an adenoma at baseline underwent a follow-up colonoscopy 4 years later (adenoma recurrence). Of these, 1731 underwent a clearing colonoscopy 1 year after the baseline examination (missed adenoma). Main Outcome Measurements Association of baseline adenoma location with the risk and location of adenomas found at colonoscopy performed 1 year and 4 years later. Results At the year 1 colonoscopy, 598 patients (34.6%) had an adenoma (missed adenoma). Compared with those with a distal-only adenoma at baseline, patients with a proximal-only adenoma at baseline were more likely to have any missed adenomas (relative risk RR 1.28; 95% CI, 1.09-1.49) and a proximal-only missed adenoma (RR 2.05; 95% CI, 1.49-2.80). At the year 4 colonoscopy, 733 patients (39.3%) had adenoma recurrence. Patients with a baseline proximal-only adenoma were more likely to have any adenoma recurrence (RR 1.14; 95% CI, 1.00-1.31) and a proximal-only adenoma recurrence (RR 1.52; 95% CI, 1.15-2.02). Sensitivity analyses involving missed adenomas did not materially affect the risk or location of recurrent adenomas at year 4 colonoscopy. Limitation Lesions may still be missed on repeated colonoscopies. Conclusions Missed and recurrent adenomas are more likely to be in the proximal colon.
Background & Aims: Although a number of epidemiologic studies have found dietary fiber and whole grains to be inversely associated with colorectal cancer incidence, studies of dietary and other risk ...factors for small intestinal cancer have been sparse and all of a case-control design. We conducted a prospective cohort study to determine the relationship between intake of dietary fiber/whole grains and the incidence of small intestinal cancer. Methods: We analyzed dietary data collected in 1995 and 1996 from 293,703 men and 198,618 women in the National Institutes of Health–AARP Diet and Health Study. We used multivariate Cox proportional hazards models to estimate relative risk (RR) and 2-sided 95% confidence intervals (CIs) for quintiles of dietary fiber and whole grain intake. Results: Through 2003, 165 individuals developed small intestinal cancers. Dietary fiber/whole grain intake was generally associated with a lower risk of small intestinal cancer. The multivariate RRs (95% CIs; 5th vs 1st intake quintile) were 0.79 (0.43–1.44; P trend, .41) for total dietary fiber, 0.51 (0.29–0.89; P trend, .01) for fiber from grains, and 0.59 (0.33–1.05; P trend, .06) for whole grain foods. Conclusions: Intake of fiber from grains and whole-grain foods was inversely associated with small intestinal cancer incidence; the RR values were consistent with those from the same dietary factors for large bowel cancer in this cohort. In conjunction with the anatomic and physiologic commonalities of the large and small bowel, as well as the mutually increased risks for second cancer for both organs, grain fiber and whole grain foods seem to protect against lower gastrointestinal cancers.
Smoking is an important risk factor for many cancers, yet the relationship between smoking and prostate cancer remains uncertain.
We investigated whether smoking affected the risk of prostate cancers ...within a large prospective cohort study of dietary and
environmental cancer risk factors among men ages 50 to 71 upon enrollment in 1995-1996 ( n = 283,312). Cox proportional hazards regression models with hazard ratios (HR) and 95% confidence intervals (95% CI) were
adjusted for age, race, education, height, body mass index, physical activity, family history of prostate cancer, diabetes,
self-reported health status, prostate-specific antigen testing, digital rectal exam, total energy, α-tocopherol, calcium,
α-linolenic acid, selenium, red meat, fish, and tomato intake. There were 14,810 nonadvanced and 1,830 advanced incident prostate
cancers identified through 2003, and 394 men died of their disease through 2005. Current smokers had a decreased risk of nonadvanced
prostate cancer (HR, 0.82; 95% CI, 0.77-0.88), but an increased risk of fatal prostate cancer (HR, 1.69; 95% CI, 1.25-2.27).
Former smoking was also associated with decreased risk of nonadvanced prostate cancers (HR, 0.89; 95% CI, 0.86-0.92), but
not fatal prostate cancers (HR, 1.03; 95% CI, 0.83-1.27). There was no apparent association between smoking and advanced prostate
cancer. A number of biologically plausible mechanisms could explain these results, including the direct effects of carcinogens
in tobacco smoke and the resulting changes in sex hormone or growth factor profiles. These findings suggest that current and
former smokers may be at decreased risk of being diagnosed with prostate cancer and current smokers are at an increased risk
of dying from prostate cancer. (Cancer Epidemiol Biomarkers Prev 2009;18(9):2427–35)
BACKGROUND: Although diet has long been suspected as an etiological factor for colorectal cancer, studies of single foods and nutrients have provided inconsistent results. OBJECTIVE: We used factor ...analysis methods to study associations between dietary patterns and colorectal cancer in middle-aged Americans. DESIGN: Diet was assessed among 293 615 men and 198 767 women in the National Institutes of Health-AARP Diet and Health Study. Principal components factor analysis identified 3 primary dietary patterns: a fruit and vegetables, a diet foods, and a red meat and potatoes pattern. State cancer registries identified 2151 incident cases of colorectal cancer in men and 959 in women between 1995 and 2000. RESULTS: Men with high scores on the fruit and vegetable pattern were at decreased risk relative risk (RR) for quintile (Q) 5 versus Q1: 0.81; 95% CI: 0.70, 0.93; P for trend = 0.004. Both men and women had a similar risk reduction with high scores on the diet food factor: men (RR: 0.82; 95% CI: 0.72, 0.94; P for trend = 0.001) and women (RR: 0.87; 95% CI: 0.71, 1.07; P for trend = 0.06). High scores on the red meat factor were associated with increased risk: men (RR: 1.17; 95% CI: 1.02, 1.35; P for trend = 0.14) and women (RR: 1.48; 95% CI: 1.20, 1.83; P for trend = 0.0002). CONCLUSIONS: These results suggest that dietary patterns characterized by a low frequency of meat and potato consumption and frequent consumption of fruit and vegetables and fat-reduced foods are consistent with a decreased risk of colorectal cancer.
Background Following adoption of a Western lifestyle, China is experiencing a decline in physical activity levels, which is projected to contribute to future increases in the burden of chronic ...diseases. Purpose This study aims to target public health interventions and identify personal characteristics associated with physical activity and sedentary behavior in urban Chinese adults. Methods In a sample of 576 men and women aged 40–74 years from Shanghai, multiple logistic regression was used to examine demographic, anthropometric, and lifestyle factors in relation to levels of physical activity and sedentary behavior assessed by Actigraph accelerometers. Results Participants spent 317 minutes/day in physical activity and 509 minutes/day sedentary. In multivariate models, people aged ≥60 years were significantly less likely than those aged <50 years to engage in physical activity (OR=0.29, 95% CI=0.17, 0.49) and more likely to spend time sedentary (OR=2.77, 95% CI=1.53, 5.05). Similarly, obese individuals were less likely to be physically active (OR=0.34, 95% CI=0.17, 0.66) and they were suggestively more likely to be sedentary (OR=1.87, 95% CI=0.94, 3.71) than normal-weight individuals. Furthermore, current cigarette smokers were less physically active than those who formerly or never smoked (OR=0.47, 95% CI=0.28, 0.78). Conclusions Physical activity promotion programs in urban China should target older people, obese individuals, and cigarette smokers, as these population subgroups exhibited low levels of physical activity.
It would be of enormous public health importance if diet and physical activity, both modifiable behavioral factors, were causally
related to cancer. Nevertheless, the nutritional epidemiology of ...cancer remains problematic, in part because of persistent
concerns that standard questionnaires measure diet and physical activity with too much error. We present a new strategy for
addressing this measurement error problem. First, as background, we note that food frequency and physical activity questionnaires
require respondents to report “typical” diet or activity over the previous year or longer. Multiple 24-hour recalls (24HR),
based on reporting only the previous day's behavior, offer potential cognitive advantages over the questionnaires, and biomarker
evidence suggests the 24-hour dietary recall is more accurate than the food frequency questionnaire. The expense involved
in administering multiple 24HRs in large epidemiologic studies, however, has up to now been prohibitive. In that context,
we suggest that Internet-based 24HRs, for both diet and physical activity, represent a practical and cost-effective approach
for incorporating multiple recalls in large epidemiologic studies. We discuss (1) recent efforts to develop such Internet-based
instruments and their accompanying software support systems; (2) ongoing studies to evaluate the feasibility of using these
new instruments in cohort studies; (3) additional investigations to gauge the accuracy of the Internet-based recalls vis-à-vis
standard instruments and biomarkers; and (4) new statistical approaches for combining the new instruments with standard assessment
tools and biomarkers The incorporation of Internet-based 24HRs into large epidemiologic studies may help advance our understanding
of the nutritional determinants of cancer. (Cancer Epidemiol Biomarkers Prev 2009;18(4):1026–32)
Understanding the relationship between multivitamin use and diabetes risk is important given the wide use of multivitamin supplements among U.S. adults.
We prospectively examined supplemental use of ...multivitamins and individual vitamins and minerals assessed in 1995-1996 in relation to self-reported diabetes diagnosed after 2000 among 232,007 participants in the National Institutes of Health-American Association of Retired Persons Diet and Health Study. Multivitamin use was assessed by a food-frequency questionnaire at baseline. Odds ratios (ORs) and 95% CIs were calculated by logistic regression models, adjusted for potential confounders. In total, 14,130 cases of diabetes diagnosed after 2000 were included in the analysis.
Frequent use of any multivitamins was not associated with risk of diabetes after adjustment for potential confounders and uses of individual supplements. Compared with nonusers of any multivitamins, the multivariate ORs among users were 1.07 (95% CI 0.94-1.21) for taking vitamins less than once per week, 0.97 (0.88-1.06) for one to three times per week, 0.92 (0.84-1.00) for four to six times per week, and 1.02 (0.98-1.06) for seven or more times per week (P for trend = 0.64). Significantly lower risk of diabetes was associated with the use of vitamin C or calcium supplements. The multivariate ORs comparing daily users with nonusers were 0.91 (0.86-0.97) for vitamin C supplements and 0.85 (0.80-0.90) for calcium supplements. Use of vitamin E or other individual vitamin and mineral supplements were not associated with diabetes risk.
In this large cohort of U.S. older adults, multivitamin use was not associated with diabetes risk. The findings of lower diabetes risk among frequent users of vitamin C or calcium supplements warrant further evaluations.
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