Dietary calcium intake as a mitigating factor in colon cancer

A population-based case-control study was conducted in Utah to test the hypothesis that calcium decreases the risk of developing colon cancer. A total of 231 cases and 391 controls were identified and interviewed between 1979 and 1982. A quantitative food frequency instrument was used to ascertain individual dietary intake two years prior to diagnosis for the cases and two years prior to interview for the controls. Calcium, calcium per 1,000 calories, and total dairy product consumption were used as indicators of dietary calcium intake. Categories of dietary intake were determined by the distribution of these variables in the control population. A protective effect was observed for males for intake of calcium (odds ratio (OR) = 0.48), calcium per 1,000 calories (OR = 0.35), and total diary products (OR = 0.49). The magnitude of the protective effect from calcium intake increased after adjusting for intake of calories (OR = 0.41), protein (OR = 0.31), and fat (OR = 0.46). Calcium provided less of a protective effect in females, with the odds ratio for calcium being 0.50, 0.55, and 0.56 after adjusting for calories, protein, and fat, respectively. Risk associated with calories, protein, and fat also increased after adjusting for calcium. Of interest is an odds ratio of 5.30 in males for protein after adjusting for calcium. A biologic mechanism is presented to help explain the role of calcium in the development of colon cancer.     

Dietary intake and colon cancer: sex- and anatomic site-specific associations

A case-control study was conducted in Utah between July 1979 and June 1983 in which 231 cases of colon cancer identified through the Utah Cancer Registry and 391 controls identified through random digit dialing were interviewed. Odds ratios (OR) were calculated comparing the highest exposure categories with the lowest exposure categories. The highest quintile of body mass index (weight (kg)/height (m)2 for males; weight (kg)/height (m)1.5 for females) was associated with increased risk in both males (OR = 2.1) and females (OR = 2.3). In females, total dietary fat (OR = 1.9) and energy intake (OR = 1.5) were associated with an increased colon cancer risk after adjusting for age, body mass index, and crude fiber. Fiber was protective in females (OR = 0.5) after adjusting for age, body mass index, and energy intake, as was beta-carotene (OR = 0.5) after also adjusting for crude fiber. Adjusted risk estimates in males were 2.0 for total dietary fat, 3.8 for polyunsaturated fat, 2.1 for monounsaturated fat, 2.1 for energy intake, 2.5 for protein, 0.3 for fiber, 0.4 for beta-carotene, and 0.3 for cruciferous vegetables. Risk estimates differed by site of cancer within the colon. In males, protein (OR = 3.8) was a risk factor for cancer of the descending colon, while fats (OR = 2.7-8.8) increased the risk of cancer of the ascending colon. The hypotheses that dietary fat increases colon cancer risk while dietary fiber decreases colon cancer risk and that fat and protein may be independently associated with colon cancer risk are supported.     

Diet and lung cancer risk: findings from the Western New York Diet Study

This study compares the diets of 450 lung cancer cases (296 males, 154 females) with those of 902 controls (587 males, 315 females). Cases were lung cancer patients diagnosed between August 1980 and July 1984 in three western New York counties, while controls were selected from the general population of these same counties. Usual diet was estimated by detailed interviews using a modified food frequency method. Case-control comparisons were made for dietary fat, protein, fiber, calories, cholesterol, and vitamins A, C, and E according to quartiles of intake, adjusting for age and pack-years of cigarettes by multiple logistic regression. Risk was lower for males in the lowest quartile of total dietary fat intake compared with those in the highest quartile (relative risk = 0.5), although the overall trend in the association with dietary fat was not statistically significant (p = 0.12). Likewise, there was a weak, but not statistically significant, direct association between dietary cholesterol and lung cancer in men (p = 0.17). The intake of vitamin A from fruits and vegetables (carotene) was much more strongly associated with reduced cancer risk. For males, the relative risks by quartiles (lowest intake to highest intake) were 1.8, 1.8, 1.0, 1.0 (p for trend = 0.001). For females, this relation was considerably weaker, and was not statistically significant. These findings are generally in agreement with those of several previous studies. The risk reduction associated with vitamin A from fruits and vegetables (carotene) was most evident for males, for those with squamous cell cancers, for light or ex-smokers, and for those over 60 years of age.     

Weight management goals and practices among U.S. high school students: associations with physical activity, diet, and smoking.

PURPOSE: To examine associations of physical activity, fruit and vegetable consumption, and cigarette smoking with weight management goals and practices of U.S. high school students.METHODS: Data were from the 1999 national Youth Risk Behavior Survey, a representative sample of U.S. high school students (n = 15,349). Adjusted odds ratios (OR) were calculated to describe associations, controlling for demographic characteristics.RESULTS: Based on self-reported height and weight, 25% of students were either overweight (11%) or at risk for becoming overweight (14%). However, 43% of students were trying to lose weight and 19% of students were trying to maintain their current weight. Female students were less likely than male students to be overweight, but more likely to be trying to lose weight. Trying to lose weight was associated with vigorous physical activity (OR = 1.5), strengthening exercises (OR = 2.2), and cigarette smoking (OR = 1.4) among female students; and vigorous physical activity (OR = 1.6), strengthening exercises (OR = 1.8), and eating > or =5 servings/day of fruits and vegetables (OR = 1.5) among male students. Among students trying to lose weight or stay the same weight, only 62% of females and 41% of males combined exercise with a reduced fat and calorie diet, while 32% of females and 17% of males used unhealthy weight control methods (fasting, diet pills, vomiting, or laxatives).CONCLUSIONS: Efforts to promote healthy weight management among adolescents are needed and should place greater emphasis on combining physical activity with a reduced fat and calorie diet, increasing fruit and vegetable consumption, and discouraging smoking and other unhealthy weight control practices.     

饮食、营养素与结肠癌——基于全人群的病例-对照研究

本文以大样本全人群病例一对照研究数据分析食物摄入频度、摄入量及营养素与结肠癌的关系。结果表明:大多数蔬菜、粗纤维、维生素C、维生素B_2、钙、铁等营养素降低结肠癌的发病危险性;动物性食品、脂肪、能量与结肠癌的发病危险性关系不甚密切;油炸、腌制、咸霉食品增高结肠癌发病的相对危险度;葱蒜类、海带紫菜与结肠癌发病危险呈负相关。还探讨了结肠癌高低发地区病因学的异同以及膳食调查的回忆误差,食物摄入频度与摄入量对反映饮食与肿瘤之间联系的差异。     

Cigarette smoking and risk of bladder, pancreas, kidney, and colorectal cancers in Iowa

PURPOSE: Although there are numerous reports on the effects of cigarette smoking and cancer, they have infrequently compared risks at more than one cancer site after multivariate adjustment. We analyzed data from a population-based case-control study that included five anatomic sites to evaluate the association between cigarette smoking and each cancer site and to rank the associations by site. METHODS: Study respondents included 1452 bladder, 406 kidney, 376 pancreatic, 685 colon, and 655 rectal cancer cases, as well as 2434 population controls. A self-administered questionnaire was used to collect information on cigarette smoking and other potential confounders including occupation, drinking water source, and dietary practices. Logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs), after adjustment for age, total energy intake, and other site- and sex-specific confounders. RESULTS: In both sexes, cigarette smoking (ever vs. never) was associated with risk of bladder cancer (OR = 2.5; 95% CI, 2.0-3.1 for males; OR = 2.7; 2.0-3.6 for females) and pancreatic cancer (OR = 1.8; 1.2-2.8 for males; OR = 2.1; 1.4-3.1 for females). Cigarette smoking also increased the risk of kidney cancer among males (OR = 1.8; 1.3-2.7), and to a lesser degree, among females (OR = 1.2; 0.8-1.8). No association was found for colon or rectal cancer in either sex. CONCLUSIONS: Cigarette smoking increased the risk of bladder, kidney, and pancreatic cancer in men and women. The rankings of multivariate-adjusted ORs from highest to lowest were bladder, pancreas, kidney, and colorectum, with little difference between men and women.     

Increased Dietary Inflammatory Index (DII) Is Associated With Increased Risk of Prostate Cancer in Jamaican Men

Prostate cancer is the most common nonskin malignancy, and it accounts for the most cancer deaths among Jamaican males. Diet has been implicated in the etiology of prostate cancer, including through its effects on inflammation. We examined the association between a newly developed dietary inflammatory index (DII) and prostate cancer in a case-control study of 40–80 yr old Jamaican males. A total of 229 incident cases and 250 controls attended the same urology out-patient clinics at 2 major hospitals and private practitioners in the Kingston, Jamaica metropolitan area between March 2005 and July 2007. The DII was computed based on dietary intake assessed using a previously validated food frequency questionnaire (FFQ) that was expanded to assess diet and cancer in this Jamaican population. Multivariable logistic regression was used to estimate odds ratios, with DII as continuous and expressed as quartiles. Logistic regression analysis adjusted for age, total energy intake, education, body mass index, smoking status, physical activity, and family history of prostate cancer. Men in the highest quartile of the DII were at higher risk of prostate cancer [odds ratio (OR) = 2.39; 95% confidence interval (CI) = 1.14–5.04; P_trend = 0.08] compared to men in the lowest DII quartile. These data suggest a proinflammatory diet, as indicated by increasing DII score, may be a risk factor for prostate cancer in Jamaican men.     

新发结直肠癌患者膳食模式分析

目的 探讨新发结直肠癌患者的膳食模式与发病的关系,为结直肠癌的发生提供科学的干预方向。方法 以2018—2019年辽宁省某肿瘤医院就诊并经病理学确诊的新发结直肠癌患者和同期在该医院体检中心参加健康体检者为研究对象,新发结直肠癌患者为病例组,按同性别、同年龄1∶1选取健康体检者作为对照组,采用主成分分析法对调查对象的膳食模式进行分析,利用Logistic回归模型分析不同膳食模式对结直肠癌发病风险的影响。结果 本研究共对新发结直肠癌患者232例、健康体检者232人进行调查,2组人群在性别、年龄、文化程度、家庭人均月收入和体力劳动强度分布差异均无统计学意义（均P>0.05）。多因素Logistic回归分析结果显示坚果薯类膳食模式（OR=0.482）、水产奶类膳食模式（OR=0.666）和果蔬素食膳食模式（OR=0.800）是结直肠癌发生的保护性因素,西式膳食模式（OR=1.441）、辛辣熏制膳食模式（OR=1.195）、肉类膳食模式（OR=1.397）和高脂肪膳食模式（OR=1.349）为结直肠癌发病的危险因素。结论 坚果薯类、水产奶类和果蔬素食是结直肠癌发生的保护性因素。西式、辛辣熏制、肉类和高脂肪膳食为结直肠癌发病的危险因素,在结直肠癌的防病宣传健康教育中应该加强饮食健康宣传,提高防病意识,有效降低发病率。     

The effects of varying dietary fat on performance and metabolism in trained male and female runners

OBJECTIVES: Low dietary fat intake has become the diet of choice for many athletes. Recent studies in animals and humans suggest that a high fat diet may increase VO2max and endurance. We studied the effects of a low, medium and high fat diet on performance and metabolism in runners. METHODS: Twelve male and 13 female runners (42 miles/week) ate diets of 16% and 31% fat for four weeks. Six males and six females increased their fat intakes to 44%. All diets were designed to be isocaloric. Endurance and VO2max were tested at the end of each diet. Plasma levels of lactate, pyruvate, glucose, glycerol, and triglycerides were measured before and after the VO2max and endurance runs. Free fatty acids were measured during the VO2max and endurance runs. RESULTS: Runners on the low fat diet ate 19% fewer calories than on the medium or high fat diets. Body weight, percent body fat (males=71 kg and 16%; females=57 kg and 19%), VO2max and anaerobic power were not affected by the level of dietary fat. Endurance time increased from the low fat to medium fat diet by 14%. No differences were seen in plasma lactate, glucose, glycerol, triglycerides and fatty acids when comparing the low versus the medium fat diet. Subjects who increased dietary fat to 44% had higher plasma pyruvate (46%) and lower lactate levels (39%) after the endurance run. CONCLUSION: These results suggest that runners on a low fat diet consume fewer calories and have reduced endurance performance than on a medium or high fat diet. A high fat diet, providing sufficient total calories, does not compromise anaerobic power.     

A case-control study of diet and testicular carcinoma.

No risk factor other than cryptorchidism has been consistently associated with testicular cancer, and the influence of diet on testicular cancer risk has not been extensively explored. A few studies have found increased testicular cancer risk in men whose diets are high in fat, red meats, and milk or low in fruits and vegetables. We evaluated the relationship of dietary factors and risk of testicular cancer and also examined whether this risk varied by type of testicular cancer. We conducted a hospital-based case-control study at The University of Texas M. D. Anderson Cancer Center (Houston, TX) of 160 testicular cancer cases diagnosed between 1990 and 1996 and 136 friend-matched controls. The results of multivariable logistic regression analysis showed that after adjustment for age, education, income, ethnicity, cryptorchidism, and total daily calories, increasing total fat, saturated fat, and cholesterol consumption were associated with increasing risk of nonseminoma testicular cancer, with odds ratios (ORs) for the highest vs. the lowest quartiles of 6.3, 5.3, and 4.6, respectively. The risk for seminoma testicular cancer marginally increased with increasing intake of total fat and saturated fat, with ORs for the highest vs. lowest quartiles of 1.9 and 2.1, respectively. Higher total fat consumption was nearly significantly related to increased mixed germ cell tumor risk, with an OR for highest vs. lowest quartile of 4.2. This study supports the hypothesis that diet (particularly high fat consumption) increases testicular cancer risk in young men. However, the small sample size and the possibility that these observations may be due to bias indicate that the relationship of diet and testicular cancer risk needs to be further examined within a prospective or incident case-control study.     

Physical activity, hormone replacement therapy, and the presence of coronary calcium in midlife women

Background: Atherosclerotic calcification is a risk factor for cardiovascular events, independent of other traditional risk factors. Studies of the relation of menopausal hormone therapy to cardiovascular events have had inconsistent results, and often have been confounded by lifestyle behaviors and the "healthy user" effect. The authors evaluated the cross-sectional association of hormone therapy use with the presence and severity of atherosclerosis in postmenopausal women, independent of lifestyle factors, including diet and physical activity levels. Methods: The authors consecutively enrolled postmenopausal asymptomatic women who were referred for coronary artery calcium scanning to measure cardiovascular risk. After consent was obtained, women were interviewed prior to their cardiac scan about cardiac risk factors, hormone therapy use, menopausal status, diet, and physical activity. Coronary artery calcium prevalence was defined as any calcification present (score >0). Results: Of the 544 enrolled women aged 50-80 years, 252 (46.3%) were hormone therapy users. Hormone therapy users had a significantly lower prevalence of any coronary artery calcium (defined as coronary artery calcium score >0; 37%), than non-users (50%, p = 0.04), as well as significantly lower mean calcium scores (p = 0.02). Multiple logistic regression models demonstrated a significantly reduced odds of coronary artery calcium in hormone therapy users compared to non-users with an adjusted odds ratio of 0.58 (p = 0.04), adjusting for traditional cardiac risk factors and body mass index. Women who reported consuming a vegetarian or a high-protein diet had almost two-fold odds of coronary artery calcium compared with women who reported regular, mixed, or low-fat, low-salt diets (OR = 1.78, p = 0.02). Severity of coronary artery calcium was less with increasing levels of physical activity, and a significant association was observed between physical activity and hormone therapy use (adjusted OR = 4.05, p = 0.03), independent of coronary artery calcium severity. Conclusion: This cross-sectional study demonstrated a protective association of hormone therapy with the presence and severity of coronary artery calcium. Although a strong relationship was observed between hormone therapy and physical activity, their complex interplay may affect mechanistic biochemical and physiological processes that have yet to be clearly delineated. Thus, physical activity and diet should be taken into account in prospective studies of the relation of hormone therapy use to coronary artery calcium.     

Asbestos and colon cancer: lack of association in a large case-control study.

Previous studies linking exposure to asbestos with human colon cancer have used mortality rather than incidence as their endpoint and have neither assessed nor controlled for confounding by diet, genetic factors, or other risk factors for colon cancer. A case-control study of 746 histologically confirmed cases of colon cancer and 746 matched neighborhood controls was conducted in Los Angeles County, California. In univariate analyses of the 419 male pairs, a weak association was found between asbestos exposure and colon cancer (odds ratio (OR) = 1.16, 95% confidence interval (CI) 0.80-1.69). When confounding by family history of large bowel cancer, diet, body weight, and physical activity was controlled, there was no association between colon cancer and exposure to asbestos among males (OR = 0.99, 95% CI 0.66-1.50). When asbestos exposure was restricted to occurrences preceding diagnosis by more than 15 years, there was no clear association between such exposure and colon cancer, either before (OR = 1.14, 95% CI 0.76-1.70) or after confounding was controlled (OR = 0.93, 95% CI 0.60-1.44). Further analyses by frequency and duration of exposure failed to show any association between asbestos and risk of colon cancer, but did show a consistent pattern of confounding by nonoccupational factors that, when controlled, invariably produced a weak protective effect of asbestos exposure. Among the 327 female pairs, only 6 cases and 11 controls reported asbestos exposure (OR = 0.55, 95% CI 0.20-1.48), and there was no evidence of risk increasing as the frequency or duration of exposure increased. This study suggests not only that occupational exposure to asbestos is not a risk factor for colon cancer in the general population of Los Angeles, but also that observed associations between asbestos and colon cancer should not be interpreted as causal unless confounding by nonoccupational factors has been evaluated and controlled.     

Diet diversity and colorectal cancer

BACKGROUND: Food diversity has been recommended to achieve a healthy diet and prevent cancer. The relation between diet diversity and the risk of colorectal cancer was investigated using data from a multicenter case-control study carried out between 1992 and 1996 in Italy. METHODS: The study included 1225 subjects with cancer of the colon (688 men and 537 women), 728 with cancer of the rectum (437 men and 291 women), and 4154 controls (2073 men and 2081 women) residing in the same geographical areas. Odds ratios (ORs) of colon and rectal cancer and the corresponding 95% confidence intervals (CI) according to food diversity were derived from unconditional multiple logistic regression equations. RESULTS: For colon cancer, an inverse association for total diversity was found in males (adjusted OR of 0.65 for the highest vs the lowest quintile of total diversity; 95% CI: 0.46-0.93) and in females (OR = 0.85; 95% CI: 0.57-1.26). With respect to specific food groups, there was an inverse association only with diversity within vegetables (OR = 0.66; 95% CI: 0.54-0.81 in colon cancer and OR = 0.71; 95% CI: 0.55-0.91 in rectal cancer). CONCLUSIONS: This study suggests that total diversity is moderately related to a decreased risk of colorectal cancer risk. A better understanding of the potential influence of dietary patterns on colorectal cancer is needed.     

Dietary lipids and the low blood cholesterol-cancer association.

The role of dietary fat and cholesterol in the low blood cholesterol-cancer association was examined in the National Health and Nutrition Survey Epidemiologic Follow-up Study (NHEFS) conducted during 1971-1984. Of the 9,593 male and female participants, aged 25-74 years, 638 developed cancer during the median of 10.2 years of follow-up. Diet was assessed using a 24-hour dietary recall. Despite an inverse association between serum cholesterol and cancer, male cases consumed, on average, more dietary cholesterol, a larger proportion of calories as saturated fat, but a similar proportion of calories as linoleic acid. Among females, cases consumed less fat and cholesterol than noncases. Among males with central adiposity (subscapular-to-triceps skinfold ratio greater than or equal to 1), cases ate more dietary cholesterol both absolutely and as a proportion of calories. Among males with peripheral adiposity, cases tended to eat less dietary cholesterol than noncases. Among females, serum cholesterol was inversely associated with cancer risk among those with central adiposity but directly associated among those with peripheral adiposity. Dietary comparisons were adjusted for age, race, body mass index, smoking status, alcohol consumption, education, and economic status. The results indicate that diet cannot explain the low blood cholesterol-cancer association in men. Furthermore, inconsistencies in the literature in this area may be due, in part, to differing proportions of central adiposity in study populations.     

Weight management and fruit and vegetable intake among US high school students

Background: Consumption of fruits and vegetables is often recommended to promote healthy weight. The purpose of this study was to examine associations between fruit and vegetable intake and common weight management behaviors among US high school students who were trying to lose or stay the same weight. Methods: Data from the 1999, 2001, and 2003 national high school Youth Risk Behavior Surveys were combined and the analyses stratified by gender (females, N = 16,709; males, N = 10,521). We considered 3 common weight management strategies—being physically active (ie, moderate activity for 30 minutes on 5 or more days per week or vigorous activity for 20 minutes on 3 or more days per week), eating a reduced calorie or fat diet, and limiting TV viewing. Sufficient fruit and vegetable intake was defined as eating 5 or more servings per day. Odds ratios (ORs) were calculated using logistic regression. Results: Only 21.3% of females and 24.7% of males ate sufficient fruits and vegetables. Being physically active was associated with sufficient fruit and vegetable intake. Eating a reduced calorie or fat diet and limiting TV viewing (among males) were associated with sufficient fruit and vegetable intake only among physically active students. The odds of sufficient fruit and vegetable intake were greatest among female (OR = 3.01) and male (OR = 2.91) students who combined all 3 strategies (31.5% of females, 21.6% of males). Conclusions: Interventions that promote fruit and vegetable intake within the context of healthy weight management may be more effective if they combine nutrition and physical activity strategies. Further research is needed to test this approach.     

Dietary risk factors for colon and rectal cancers: a comparative case-control study

BACKGROUND: In Japan, the incidence rate of colon cancer has more rapidly increased than that of rectal cancer. The differential secular trends may be due to different dietary factors in the development of colon and rectal cancers. METHODS: To compare dietary risk factors between colon and rectal cancers, we undertook a case-control study at Aichi Cancer Center Hospital, Japan. Subjects were 507 patients with newly diagnosed colon (n = 265) and rectal (n = 242) cancers, and 2,535 cancer-free outpatients (controls). Intakes of nutrients and food groups were assessed with a food frequency questionnaire, and multivariate-adjusted odds ratios (ORs) were estimated using unconditional logistic models. RESULTS: We found a decreasing risk of colon cancer with increasing intakes of calcium and insoluble dietary fiber; the multivariate ORs across quartiles of intake were 1.00, 0.90, 0.80, and 0.67 (trend p = 0.040), and 1.00, 0.69, 0.64, and 0.65 (trend p = 0.027), respectively. For rectal cancer, a higher consumption of carotene and meat was associated with a reduced risk; the corresponding ORs were 1.00, 1.10, 0.71, and 0.70 for carotene (trend p = 0.028), and 1.00, 0.99, 0.68, and 0.72 for meat (trend p = 0.036). Carbohydrate intake was positively correlated with the risk of rectal cancer (ORs over quartiles: 1.00, 1.14, 1.42, and 1.54; trend p = 0.048). This association was stronger in women, while fat consumption was inversely correlated with the risk of female colon and rectal cancers. CONCLUSIONS: Dietary risk factors appear to considerably differ between colon and rectal cancers.     

Fat from different foods show diverging relations with breast cancer risk in postmenopausal women

The aim was to explore previous findings within the Malm? Diet and Cancer cohort (Sweden) that omega6-fatty acid intakes are positively associated with breast cancer risk among women 50 yr of age and older and specifically examine relations between breast cancer risk and fat from different food groups. Incident breast cancer cases (n = 237) were matched to controls (n = 673) on age and screening date. A modified diet history method, a structured questionnaire, and anthropometric measurements provided data. Fat-food variables from 24 food groups were computed. Conditional logistic regression examined breast cancer risk associated with energy-adjusted exposure categories of fat-food variables. Fat from fermented milk products was negatively associated with breast cancer risk (trend, P = 0.003). The highest quartiles of vegetable oil-based dietary fats (odds ratio, OR = 1.74; confidence interval, CI = 1.12-2.72) and dried soup powders (OR = 1.59; CI = 1.04-2.43) showed positive associations. Dietary fiber did not influence associations.     

Association of dietary quercetin with reduced risk of proximal colon cancer

Quercetin is a flavonol that appears to be protective against several cancers, but its possible role in prevention of colorectal cancer is not yet well studied. We evaluated dietary intakes of quercetin and risk of colorectal cancer in a large case-control study conducted in metropolitan Detroit, Michigan (N = 2664). The protective effects of quercetin intake, as assessed by a food frequency questionnaire, were confined to risk of proximal colon cancer. Stratified analyses showed that the protective effects of quercetin on risk of proximal colon cancer were significant only when fruit intake or the Healthy Eating Index score was high, or when tea intake was low, with odds ratios (OR) for the highest vs. the lowest quartile of 0.49, 0.44, and 0.51, respectively. Increased quercetin intake had no protective effects when tea intake was high. Interestingly, increased intake of quercetin was associated with increased risk of distal colon cancer when total fruit intake was low (OR for the highest vs. the lowest quartile = 1.99). These results suggest that quercetin can have disparate effects on colon cancer risk depending on whether dietary intakes of fruit or tea are high, and that quercetin had protective effects only on proximal, not distal, colon cancer.     

Dietary sodium and potassium intake and colorectal cancer risk

In a large, comprehensive, population-based case-control study of colorectal cancer (The Melbourne Colorectal Cancer Study), a high intake of sodium was shown to be a statistically significant risk factor for rectal cancer in males (RR = 1.72, p = 0.01) and was close to statistical significance in females (RR = 1.58, p = 0.06). This was independent of previously described dietary risk factors and also independent of the previously described beer risk. A high intake of potassium was protective for both males and females, but this effect disappeared after adjustment was made for the previously described dietary risk factors. A high ratio of dietary potassium to sodium was a statistically significant protective factor in females for both colon and rectal cancer, and the significance of this effect was reduced after adjustment was made for the previously described dietary risk factor (RR for colon cancer = 0.70, p = 0.08; RR for rectal cancer = 0.67, p = 0.08). So far, no biological explanations are available for these associations, and while they are of obvious etiologic interest, they should be interpreted with caution.     

Diet, smoking, and alcohol in cancer of the larynx: a case-control study.

A case-control study among white men in western New York was conducted from 1975 through 1985 to examine diet and other risk factors for laryngeal cancer. Incident pathologically confirmed cases (250) and age- and neighborhood-matched controls (250) were interviewed to determine usual diet and lifetime use of tobacco and alcohol. Cigarettes were strongly associated with risk; pipes and cigars were not. Beer and hard liquor but not wine were associated with increased risk. Dietary fat and carotenoids were related to risk in opposite ways. The upper quartile odds ratio for dietary fat was 2.40 [95% confidence interval 1.26, 4.55], and the upper quartile odds ratio for carotenoids was 0.51 (0.26, 1.01). There was effect modification by smoking. Carotenoids were most negatively associated with risk among the lightest smokers, whereas dietary fat was most positively associated with risk among the heaviest smokers. Total calories, protein, and retinol were associated with increased risk; there was no relationship between laryngeal cancer and vitamin C, vitamin E, carbohydrate, or dietary fiber. This study again demonstrates the strong association between tobacco and alcohol and laryngeal cancer and also suggests that diets low in carotenoids and high in fat may increase risk.