Colorectal cancers soon after colonoscopy: a pooled multicohort analysis.

OBJECTIVE: Some individuals are diagnosed with colorectal cancer (CRC) despite recent colonoscopy. We examined individuals under colonoscopic surveillance for colonic adenomas to assess possible reasons for diagnosing cancer after a recent colonoscopy with complete removal of any identified polyps. DESIGN: Primary data were pooled from eight large (>800 patients) North American studies in which participants with adenoma(s) had a baseline colonoscopy (with intent to remove all visualised lesions) and were followed with subsequent colonoscopy. We used an algorithm based on the time from previous colonoscopy and the presence, size and histology of adenomas detected at prior exam to assign interval cancers as likely being new, missed, incompletely resected (while previously an adenoma) or due to failed biopsy detection. RESULTS: 9167 participants (mean age 62) were included in the analyses, with a median follow-up of 47.2 months. Invasive cancer was diagnosed in 58 patients (0.6%) during follow-up (1.71 per 1000 person-years follow-up). Most cancers (78%) were early stage (I or II); however, 9 (16%) resulted in death from CRC. We classified 30 cancers (52%) as probable missed lesions, 11 (19%) as possibly related to incomplete resection of an earlier, non-invasive lesion and 14 (24%) as probable new lesions. The cancer diagnosis may have been delayed in three cases (5%) because of failed biopsy detection. CONCLUSIONS: Despite recent colonoscopy with intent to remove all neoplasia, CRC will occasionally be diagnosed. These cancers primarily seem to represent lesions that were missed or incompletely removed at the prior colonoscopy and might be avoided by increased emphasis on identifying and completely removing all neoplastic lesions at colonoscopy.

Pooled results from 5 validation studies of dietary self-report instruments using recovery biomarkers for energy and protein intake.

We pooled data from 5 large validation studies of dietary self-report instruments that used recovery biomarkers as references to clarify the measurement properties of food frequency questionnaires (FFQs) and 24-hour recalls. The studies were conducted in widely differing US adult populations from 1999 to 2009. We report on total energy, protein, and protein density intakes. Results were similar across sexes, but there was heterogeneity across studies. Using a FFQ, the average correlation coefficients for reported versus true intakes for energy, protein, and protein density were 0.21, 0.29, and 0.41, respectively. Using a single 24-hour recall, the coefficients were 0.26, 0.40, and 0.36, respectively, for the same nutrients and rose to 0.31, 0.49, and 0.46 when three 24-hour recalls were averaged. The average rate of under-reporting of energy intake was 28% with a FFQ and 15% with a single 24-hour recall, but the percentages were lower for protein. Personal characteristics related to under-reporting were body mass index, educational level, and age. Calibration equations for true intake that included personal characteristics provided improved prediction. This project establishes that FFQs have stronger correlations with truth for protein density than for absolute protein intake, that the use of multiple 24-hour recalls substantially increases the correlations when compared with a single 24-hour recall, and that body mass index strongly predicts under-reporting of energy and protein intakes.

Body-mass index and mortality among 1.46 million white adults.

BACKGROUND: A high body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) is associated with increased mortality from cardiovascular disease and certain cancers, but the precise relationship between BMI and all-cause mortality remains uncertain. METHODS: We used Cox regression to estimate hazard ratios and 95% confidence intervals for an association between BMI and all-cause mortality, adjusting for age, study, physical activity, alcohol consumption, education, and marital status in pooled data from 19 prospective studies encompassing 1.46 million white adults, 19 to 84 years of age (median, 58). RESULTS: The median baseline BMI was 26.2. During a median follow-up period of 10 years (range, 5 to 28), 160,087 deaths were identified. Among healthy participants who never smoked, there was a J-shaped relationship between BMI and all-cause mortality. With a BMI of 22.5 to 24.9 as the reference category, hazard ratios among women were 1.47 (95 percent confidence interval [CI], 1.33 to 1.62) for a BMI of 15.0 to 18.4; 1.14 (95% CI, 1.07 to 1.22) for a BMI of 18.5 to 19.9; 1.00 (95% CI, 0.96 to 1.04) for a BMI of 20.0 to 22.4; 1.13 (95% CI, 1.09 to 1.17) for a BMI of 25.0 to 29.9; 1.44 (95% CI, 1.38 to 1.50) for a BMI of 30.0 to 34.9; 1.88 (95% CI, 1.77 to 2.00) for a BMI of 35.0 to 39.9; and 2.51 (95% CI, 2.30 to 2.73) for a BMI of 40.0 to 49.9. In general, the hazard ratios for the men were similar. Hazard ratios for a BMI below 20.0 were attenuated with longer-term follow-up. CONCLUSIONS: In white adults, overweight and obesity (and possibly underweight) are associated with increased all-cause mortality. All-cause mortality is generally lowest with a BMI of 20.0 to 24.9.

The promise and peril of surrogate end points in cancer research.

Both experimental and observational studies of cancer need to have an end point. Traditionally, in aetiological and prevention studies, that end point has been the incidence of cancer itself, whereas in therapeutic trials, the end point is usually time to cancer recurrence or death. But cancer takes a long time to develop in an individual and is rare in the population. Therefore, aetiological studies and prevention trials must be large and lengthy to be meaningful. Similarly, many therapeutic trials require a long follow-up of large numbers of patients. Surrogate end points--markers of preclinical cancer or of imminent recurrence--are therefore an attractive alternative. But how can we be sure that a study with a surrogate outcome gives us the right answer about the true end point?

A prospective cohort study of obesity and risk of oesophageal and gastric adenocarcinoma in the NIH-AARP Diet and Health Study.

OBJECTIVE: The incidence of oesophageal adenocarcinoma (EAC) has increased rapidly over the past 40 years and accumulating evidence suggests that obesity, as measured by body mass index (BMI), is a major risk factor. It remains unclear whether abdominal obesity is associated with EAC and gastric adenocarcinoma. DESIGN: Cox proportional hazards regression was used to examine associations between overall and abdominal obesity with EAC and gastric adenocarcinoma among 218 854 participants in the prospective NIH-AARP cohort. RESULTS: 253 incident EAC, 191 gastric cardia adenocarcinomas and 125 gastric non-cardia adenocarcinomas accrued to the cohort. Overall obesity (BMI) was positively associated with EAC and gastric cardia adenocarcinoma risk (highest (≥35 kg/m(2)) vs referent (18.5-<25 kg/m(2)); HR 2.11, 95% CI 1.09 to 4.09 and HR 3.67, 95% CI 2.00 to 6.71, respectively). Waist circumference was also positively associated with EAC and gastric cardia adenocarcinoma risk (highest vs referent; HR 2.01, 95% CI 1.35 to 3.00 and HR 2.22, 95% CI 1.43 to 3.47, respectively), whereas waist-to-hip ratio (WHR) was positively associated with EAC risk only (highest vs referent; HR 1.81, 95% CI 1.24 to 2.64) and persisted in patients with normal BMI (18.5-<25 kg/m(2)). Mutual adjustment of WHR and BMI attenuated both, but did not eliminate the positive associations for either with risk of EAC. In contrast, the majority of the anthropometric variables were not associated with adenocarcinomas of the gastric non-cardia. CONCLUSION: Overall obesity was associated with a higher risk of EAC and gastric cardia adenocarcinoma, whereas abdominal obesity was found to be associated with increased EAC risk; even in people with normal BMI.

Body fat distribution, weight change during adulthood, and thyroid cancer risk in the NIH-AARP Diet and Health Study.

Body mass index (BMI) has been positively associated with thyroid cancer risk in several studies, but the underlying mechanisms remain unclear. We examined the associations for waist and hip circumference and weight change during adulthood with thyroid cancer risk among 125,347 men and 72,363 women in the NIH-AARP Diet and Health Study who completed a second mailed questionnaire in 1996-1997. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated separately by sex and adjusted for race/ethnicity, education and smoking status. During follow-up (median = 10.1 years), 106 men and 105 women were diagnosed with a first primary thyroid cancer, as identified through linkage to state cancer registries. Having a large waist circumference (above the clinical cutpoint for normal: > 102 cm in men and > 88 cm in women) was associated with increased risk in both men (HR = 1.79, 95% CI: 1.21-2.63) and women (HR = 1.54, 95% CI: 1.05-2.26). Having both a large waist and BMI in the obese range (≥ 30 kg/m2) approximately doubled the risk of thyroid cancer (HR in men = 2.13, 95% CI: 1.18-3.85; HR in women = 1.91, 95% CI: 1.31-3.25) compared to having a normal waist circumference/normal BMI (18.5-24.9 kg/m2). We also observed positive association for weight gain between ages 18-35 in men (gained ≥ 10.0 kg vs. lost/gained < 5 kg, HR = 1.49, 95% CI: 0.93-2.39, p-trend = 0.03), but the association was less pronounced in women. No clear association for weight gain in later life was observed. These results support a potential role for hormonal and metabolic parameters common to central adiposity in thyroid carcinogenesis.

Dietary lignan and proanthocyanidin consumption and colorectal adenoma recurrence in the Polyp Prevention Trial.

Lignans and proanthocyanidins are plant polyphenols that have shown protective properties against colorectal neoplasms in some human studies. Using logistic regression, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) to prospectively evaluate the association between lignan and proanthocyanidin intake, estimated from databases linked to a food frequency questionnaire, and adenoma recurrence in 1,859 participants of the Polyp Prevention Trial. Overall, individual or total lignans or proanthocyanidins were not associated with colorectal adenoma recurrence. However, in sex-specific analyses, total lignan intake was positively associated with any adenoma recurrence in women (highest vs. lowest lignan intake quartile OR = 2.07, 95% CI: 1.22-3.52, p trend = 0.004) but not in men (p interaction = 0.04). To conclude, dietary lignan and proanthocyanidin consumption were not generally related to colorectal adenoma recurrence; however, high lignan intake may increase the risk of adenoma recurrence in women.

Association of dietary fat intakes with risk of esophageal and gastric cancer in the NIH-AARP diet and health study.

The aim of our study was to investigate whether intakes of total fat and fat subtypes were associated with esophageal adenocarcinoma (EAC), esophageal squamous cell carcinoma (ESCC), gastric cardia or gastric noncardia adenocarcinoma. From 1995-1996, dietary intake data was reported by 494,978 participants of the NIH-AARP cohort. The 630 EAC, 215 ESCC, 454 gastric cardia and 501 gastric noncardia adenocarcinomas accrued to the cohort. Cox proportional hazards regression was used to examine the association between the dietary fat intakes, whilst adjusting for potential confounders. Although apparent associations were observed in energy-adjusted models, multivariate adjustment attenuated results to null [e.g., EAC energy adjusted hazard ratio (HR) and 95% confidence interval (95% CI) 1.66 (1.27-2.18) p for trend <0.01; EAC multivariate adjusted HR (95% CI) 1.17 (0.84-1.64) p for trend = 0.58]. Similar patterns were also observed for fat subtypes [e.g., EAC saturated fat, energy adjusted HR (95% CI) 1.79 (1.37-2.33) p for trend <0.01; EAC saturated fat, multivariate adjusted HR (95% CI) 1.27 (0.91-1.78) p for trend = 0.28]. However, in multivariate models an inverse association for polyunsaturated fat (continuous) was seen for EAC in subjects with a body mass index (BMI) in the normal range (18.5-<25 kg/m(2)) [HR (95% CI) 0.76 (0.63-0.92)], that was not present in overweight subjects [HR (95% CI) 1.04 (0.96-1.14)], or in unstratified analysis [HR (95% CI) 0.97 (0.90-1.05)]. p for interaction = 0.02. Overall, we found null associations between the dietary fat intakes with esophageal or gastric cancer risk; although a protective effect of polyunsaturated fat intake was seen for EAC in subjects with a normal BMI.

Sugars in diet and risk of cancer in the NIH-AARP Diet and Health Study.

Prospective epidemiologic data on the effects of different types of dietary sugars on cancer incidence have been limited. In this report, we investigated the association of total sugars, sucrose, fructose, added sugars, added sucrose and added fructose in the diet with risk of 24 malignancies. Participants (n = 435,674) aged 50-71 years from the NIH-AARP Diet and Health Study were followed for 7.2 years. The intake of individual sugars was assessed using a 124-item food frequency questionnaire (FFQ). Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) in multivariable models adjusted for confounding factors pertinent to individual cancers. We identified 29,099 cancer cases in men and 13,355 cases in women. In gender-combined analyses, added sugars were positively associated with risk of esophageal adenocarcinoma (HR(Q5 vs. Q1) : 1.62, 95% CI: 1.07-2.45; p(trend) = 0.01), added fructose was associated with risk of small intestine cancer (HR(Q5 vs. Q1) : 2.20, 95% CI: 1.16-4.16; p(trend) = 0.009) and all investigated sugars were associated with increased risk of pleural cancer. In women, all investigated sugars were inversely associated with ovarian cancer. We found no association between dietary sugars and risk of colorectal or any other major cancer. Measurement error in FFQ-reported dietary sugars may have limited our ability to obtain more conclusive findings. Statistically significant associations observed for the rare cancers are of interest and warrant further investigation.

Coffee intake and breast cancer risk in the NIH-AARP diet and health study cohort.

There are several biologic mechanisms whereby coffee might reduce breast cancer risk. Caffeine and caffeic acid, major coffee constituents, have been shown to suppress mammary tumor formation in animal models and to inhibit DNA methylation in human breast cancer cells, respectively. Coffee may also reduce risk through decreasing inflammation and influencing estrogen metabolism. However, epidemiologic studies have been inconsistent and few studies have examined the association by estrogen and progesterone receptor (ER/PR) status. We evaluated coffee intake for its effect on incident breast cancer in the National Institutes of Health-AARP Diet and Health Study cohort, which included 198,404 women aged 50-71 with no history of cancer, who in 1995-1996 completed a questionnaire capturing usual coffee intake over the past year. State cancer registry and mortality index linkage identified 9,915 primary incident breast carcinomas through December 2006; available information on hormone receptor (HR) status identified 2,051 ER+/PR+ and 453 ER-/PR- cancers. In multivariable proportional hazards models, coffee intake was not associated with breast cancer risk (p-value for trend = 0.38; relative risk = 0.98, 95% confidence interval: 0.91-1.07, for four or more cups per day as compared to women who never drank coffee), and results did not vary by body mass index or history of benign breast biopsy (p-value for interaction > 0.10). We found no evidence of a relationship with either caffeinated or decaffeinated coffee. Null findings persisted for risk of both HR-positive and -negative breast cancers. These findings from a large prospective cohort do not support a role of coffee intake in breast carcinogenesis.

Intake of fruits and vegetables and risk of pancreatic cancer in a pooled analysis of 14 cohort studies.

Fruit and vegetable intake may protect against pancreatic cancer, since fruits and vegetables are rich in potentially cancer-preventive nutrients. Most case-control studies have found inverse associations between fruit and vegetable intake and pancreatic cancer risk, although bias due to reporting error cannot be ruled out. In most prospective studies, inverse associations have been weaker and imprecise because of small numbers of cases. The authors examined fruit and vegetable intake in relation to pancreatic cancer risk in a pooled analysis of 14 prospective studies from North America, Europe, and Australia (study periods between 1980 and 2005). Relative risks and 2-sided 95% confidence intervals were estimated separately for the 14 studies using the Cox proportional hazards model and were then pooled using a random-effects model. Of 862,584 men and women followed for 7-20 years, 2,212 developed pancreatic cancer. The pooled multivariate relative risks of pancreatic cancer per 100-g/day increase in intake were 1.01 (95% confidence interval (CI): 0.99, 1.03) for total fruits and vegetables, 1.01 (95% CI: 0.99, 1.03) for total fruits, and 1.02 (95% CI: 0.99, 1.06) for total vegetables. Associations were similar for men and women separately and across studies. These results suggest that fruit and vegetable intake during adulthood is not associated with a reduced pancreatic cancer risk.

Health status, neighborhood socioeconomic context, and premature mortality in the United States: The National Institutes of Health-AARP Diet and Health Study.

OBJECTIVES: We examined whether the risk of premature mortality associated with living in socioeconomically deprived neighborhoods varies according to the health status of individuals. METHODS: Community-dwelling adults (n = 566,402; age = 50-71 years) in 6 US states and 2 metropolitan areas participated in the ongoing prospective National Institutes of Health-AARP Diet and Health Study, which began in 1995. We used baseline data for 565,679 participants on health behaviors, self-rated health status, and medical history, collected by mailed questionnaires. Participants were linked to 2000 census data for an index of census tract socioeconomic deprivation. The main outcome was all-cause mortality ascertained through 2006. RESULTS: In adjusted survival analyses of persons in good-to-excellent health at baseline, risk of mortality increased with increasing levels of census tract socioeconomic deprivation. Neighborhood socioeconomic mortality disparities among persons in fair-to-poor health were not statistically significant after adjustment for demographic characteristics, educational achievement, lifestyle, and medical conditions. CONCLUSIONS: Neighborhood socioeconomic inequalities lead to large disparities in risk of premature mortality among healthy US adults but not among those in poor health.

Strength of the relationships between three self-reported dietary intake instruments and serum carotenoids: the Observing Energy and Protein Nutrition (OPEN) Study.

OBJECTIVE: To assess the strength of the relationships between serum carotenoids and three self-reported dietary intake instruments often used to characterize carotenoid intake in studies of diet and disease. DESIGN: Participants completed a Diet History Questionnaire (DHQ), two 24 h dietary recalls (24HR), a fruit and vegetable screener and a fasting blood draw. We derived dietary intake estimates of α-carotene, ß-carotene, cryptoxanthin, lutein, zeaxanthin and lycopene from each diet instrument and calculated sex-specific multivariate correlations between dietary intake estimates and their corresponding serum values. SETTING: Montgomery County, Maryland, USA. SUBJECTS: Four hundred and seventy women and men aged 40-69 years in the National Cancer Institute's Observing Protein and Energy Nutrition (OPEN) Study. RESULTS: Serum carotenoids correlated more strongly with the DHQ (r = 0·34-0·54 for women; r = 0·38-0·56 for men) than with the average of two recalls (r = 0·26-0·47 for women; r = 0·26-0·40 for men) with the exception of zeaxanthin, for which the correlations using recalls were higher. With adjustment for within-person variation, correlations between serum carotenoids and recalls were greatly improved (r = 0·38-0·83 for women; r = 0·42-0·74 for men). In most cases, correlations between serum carotenoids and the fruit and vegetable screener resembled serum-DHQ correlations. CONCLUSIONS: Evidence from the study provides support for the use of the DHQ, a fruit and vegetable screener and deattenuated recalls for estimating carotenoid status in studies without serum measures, and draws attention to the importance of adjusting for intra-individual variability when using recalls to estimate carotenoid values.

Lifestyle factors and risk for new-onset diabetes: a population-based cohort study.

BACKGROUND: Epidemiologic data on the combined influence of several lifestyle factors on diabetes risk are rare, particularly among older adults. OBJECTIVE: To examine how combinations of lifestyle risk factors relate to the 11-year risk for incident diabetes. DESIGN: Population-based prospective cohort study. SETTING: National Institutes of Health (NIH)-AARP Diet and Health Study. PARTICIPANTS: 114,996 men and 92,483 women, aged 50 to 71 years in 1995 to 1996, without evidence of heart disease, cancer, or diabetes. MEASUREMENTS: A comprehensive survey of demographic characteristics and lifestyle factors, including dietary intake, body weight and height, physical activity, smoking, and alcohol consumption at baseline (1995 to 1996). Low-risk groups were formed by dichotomizing each lifestyle factor. Incident self-reported, physician-diagnosed diabetes was identified with a follow-up survey in 2004 to 2006. RESULTS: 11,031 men (9.6%) and 6969 women (7.5%) developed new-onset diabetes. For each additional lifestyle factor in the low-risk group, the odds for diabetes were 31% lower (odds ratio [OR], 0.69 [95% CI, 0.68 to 0.71]) among men and 39% lower (OR, 0.61 [CI, 0.60 to 0.63]) among women. Men and women whose diet score, physical activity level, smoking status, and alcohol use were all in the low-risk group had ORs for diabetes of 0.61 (CI, 0.56 to 0.66) and 0.43 (CI, 0.34 to 0.55), respectively. When absence of overweight or obesity was added, the respective ORs were 0.28 (CI, 0.23 to 0.34) and 0.16 (CI, 0.10 to 0.24) for men and women. Results did not differ by family history of diabetes or level of adiposity. LIMITATION: The study was observational, with potential for residual confounding. CONCLUSION: Lifestyle factors, when considered in combination, are associated with a substantial reduction in risk for diabetes. PRIMARY FUNDING SOURCE: The NIH-AARP Diet and Health Study was supported by the Intramural Research Program of the NIH.

Concentration of folate in colorectal tissue biopsies predicts prevalence of adenomatous polyps.

BACKGROUND AND AIMS: Folate has been implicated as a potential aetiological factor for colorectal cancer. Previous research has not adequately exploited concentrations of folate in normal colonic mucosal biopsies to examine the issue. METHODS: Logistic regression models were used to estimate ORs and 95% CIs of adenoma according to the tissue concentration of folate using asymptomatic average-risk women (40-70 years) in a colorectal cancer screening study. Of the 1593 eligible women who were offered enrolment, 1483 (93%) participated. Colonoscopy was complete to the caecum in 98.7% (1463/1483) of the subjects, and normal colonic tissue biopsies were obtained from 813 (56%) of these, of whom 170 had at least one adenoma. RESULTS: A marginal reduction in risk for proximal adenomas (OR 0.56, 95% CI 0.29 to 1.09) but not distal adenomas (OR 1.01, 95% CI 0.43 to 2.37) was observed among women in the highest quintile of tissue folate concentration. A significant reduction in risk for advanced adenoma was observed for women in the highest quintile of tissue folate concentration (OR 0.24, 95% CI 0.06 to 0.93). Defining the outcome as proximal adenomatous and/or hyperplastic polyps, statistically significant inverse associations with tissue concentrations of folate were also observed (OR 0.54, 95% CI 0.31 to 0.95 for quintile 5 vs quintile 1). CONCLUSIONS: These findings are consistent with the hypothesis that folate status of colonic mucosa is an exposure that is aetiologically important in determining the risk of particular molecular subtypes of colorectal cancer.

Reproductive factors and exogenous hormone use and risk of adult glioma in women in the NIH-AARP Diet and Health Study.

Experimental evidence suggests that estrogen and other steroid hormones may protect against glioma. Although epidemiologic studies provide only weak support for a role of exogenous or endogenous hormones in gliogenesis, few cohort studies have addressed this question. The authors, therefore, examined the association between menstrual and reproductive factors, exogenous hormone use, and glioma risk among 225,355 women aged 50-71 years who completed the baseline questionnaire in the NIH-AARP Diet and Health Study. During 7.5 years of follow-up, 174 cases of incident, primary glioma were ascertained. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI) for exposures, taking potential confounders into account. Older age at menarche was positively associated with risk: HR 1.67 (95% CI: 1.03, 2.69). Other reproductive factors, including age at first live birth, parity, age at menopause, type of menopause (natural vs. medical) and exogenous hormone use showed no association with glioma risk. The results were similar when the analysis was restricted to cases with glioblastoma (N = 130). The present study provides only limited support for the hypothesis that menstrual/reproductive factors or exogenous hormone use play a role in gliogenesis.

Dietary nitrate and nitrite and the risk of thyroid cancer in the NIH-AARP Diet and Health Study.

During the past several decades, an increasing incidence of thyroid cancer has been observed worldwide. Nitrate inhibits iodide uptake by the thyroid, potentially disrupting thyroid function. An increased risk of thyroid cancer associated with nitrate intake was recently reported in a cohort study of older women in Iowa. We evaluated dietary nitrate and nitrite intake and thyroid cancer risk overall and for subtypes in the National Institutes of Health-American Association of Retired Persons (NIH-AARP) Diet and Health Study, a large prospective cohort of 490,194 men and women, ages 50-71 years in 1995-1996. Dietary intakes were assessed using a 124-item food frequency questionnaire. During an average of 7 years of follow-up we identified 370 incident thyroid cancer cases (170 men, 200 women) with complete dietary information. Among men, increasing nitrate intake was positively associated with thyroid cancer risk (relative risk [RR] for the highest quintile versus lowest quintile RR = 2.28, 95% confidence interval [CI]: 1.29-4.041; p-trend <0.001); however, we observed no trend with intake among women (p-trend = 0.61). Nitrite intake was not associated with risk of thyroid cancer for either men or women. We evaluated risk for the two main types of thyroid cancer. We found positive associations for nitrate intake and both papillary (RR = 2.10; 95% CI: 1.09-4.05; p-trend = 0.05) and follicular thyroid cancer (RR = 3.42; 95% CI: 1.03-11.4; p-trend = 0.01) among men. Nitrite intake was associated with increased risk of follicular thyroid cancer (RR = 2.74; 95%CI: 0.86-8.77; p-trend = 0.04) among men. Our results support a role of nitrate in thyroid cancer risk and suggest that further studies to investigate these exposures are warranted.

Alcohol and endometrial cancer risk in the NIH-AARP diet and health study.

Previous investigations have provided conflicting results regarding whether alcohol consumption affects endometrial cancer risk, although in many of these studies the highest category of alcohol intake examined was limited. Further, most were unable to resolve how alcohol associations are affected by beverage type, the presence of other endometrial cancer risk factors, or tumor characteristics. To address these issues, we prospectively evaluated the association between alcohol intake and incident endometrial cancer (n = 1,491) in a cohort of 114,414 US women enrolled in the NIH-AARP Diet and Health Study. We calculated relative risks (RR) and 95% confidence intervals (CI) using Cox proportional hazards regression. After adjustment for age, body mass index (BMI), smoking and other potential confounders, the multivariable RRs (and 95% CIs) compared with nondrinkers were 0.97 (0.87-1.09) for >0-<12 g of alcohol/day, 1.06 (0.87-1.31) for 12-<24 g/day and 0.93 (0.71-1.20) for ≥ 24 g/day (p trend = 0.90). There was, however, some suggestion of higher risks associated with alcohol consumption among lean women (BMI, <25) and users of menopausal hormone therapy, with significant interactions with both parameters (respective interaction p-values of 0.002 and 0.005). The relationship was also enhanced, albeit nonsignificantly so, for low grade cancers. Our results do not support that alcohol is a strong contributor to endometrial cancer risk, but slight risk increases may prevail among some users or for selected tumor characteristics.

Daytime napping, nighttime sleeping, and Parkinson disease.

Preliminary evidence suggests that daytime sleepiness may predate clinical diagnosis of Parkinson disease. The authors examined daytime napping and nighttime sleeping durations, reported in 1996-1997 by 220,934 US NIH-AARP Diet and Health Study participants, in relation to Parkinson disease diagnoses at 3 clinical stages: established (cases diagnosed before 1995, n = 267), recent (1995-1999, n = 396), and prediagnostic (2000 and after, n = 770). Odds ratios and 95% confidence intervals were derived from multivariate logistic regression models. Longer daytime napping was associated with higher odds of Parkinson disease at all 3 clinical stages: the odds ratios comparing long nappers (>1 hour/day) with nonnappers were 3.9 (95% confidence interval: 2.8, 5.6) for established cases, 2.2 (95% confidence interval: 1.7, 3.0) for recent cases, and 1.5 (95% confidence interval: 1.2, 1.9) for prediagnostic cases. Further control for health status or nighttime sleeping duration attenuated the association for established cases but made little difference for recent or prediagnostic cases. In the nighttime sleeping analysis, a clear U-shaped association with Parkinson disease was observed for established cases; however, this association was attenuated markedly for recent cases and disappeared for prediagnostic cases. This study supports the notion that daytime sleepiness, but not nighttime sleeping duration, is one of the early nonmotor symptoms of Parkinson disease.

Pancreatic cancer and exposure to dietary nitrate and nitrite in the NIH-AARP Diet and Health Study.

Nitrate and nitrite are precursors of N-nitroso compounds, which induce tumors of the pancreas in animals. The authors evaluated the relation of dietary nitrate and nitrite to pancreatic cancer risk in the NIH-AARP Diet and Health Study. Nitrate and nitrite intakes were assessed at baseline using a 124-item food frequency questionnaire. During approximately 10 years of follow-up between 1995 and 2006, 1,728 incident pancreatic cancer cases were identified. There was no association between total nitrate or nitrite intake and pancreatic cancer in men or women. However, men in the highest quintile of summed nitrate/nitrite intake from processed meat had a nonsignificantly elevated risk of pancreatic cancer (hazard ratio = 1.18, 95% confidence interval: 0.95, 1.47; P-trend = 0.11). The authors observed a stronger increase in risk among men for nitrate/nitrite intake from processed meat at ages 12-13 years (highest quintile vs. lowest: hazard ratio = 1.32, 95% confidence interval: 0.99, 1.76; P-trend = 0.11), though the relation did not achieve statistical significance. The authors found no associations between adult or adolescent nitrate or nitrite intake from processed meats and pancreatic cancer among women. These results provide modest evidence that processed meat sources of dietary nitrate and nitrite may be associated with pancreatic cancer among men and provide no support for the hypothesis in women.