Biomedical subjects

R W Haile

Publications and source records attributed to R W Haile.

At least 55 records · Page 3Linked to original sources

PubMed1996

Relation of vegetable, fruit, and grain consumption to colorectal adenomatous polyps.

Previous studies suggest that colorectal cancer risk decreases with higher intake of vegetables, fruits, and grains. Few studies, however, have examined these factors in relation to occurrence of colorectal polyps. The authors used case-control data from 488 matched pairs to evaluate associations of vegetables, fruits, and grains with polyps. Subjects were southern Californians aged 50-74 years who had a sigmoidoscopy in 1991-1993. Diet in the year before sigmoidoscopy was measured with a food frequency questionnaire. Frequent consumption of vegetables, fruits, and grains was associated with decreased polyp prevalence. Specifically, the adjusted odds ratio comparing the highest with the lowest quintile of intake for vegetables was 0.47 (95% confidence interval (CI) 0.29-0.76), for fruits was 0.65 (95% CI 0.40-1.05), and for grains was 0.55 (95% CI 0.33-0.91). The authors also found inverse associations for high carotenoid vegetables, cruciferae, high vitamin C fruits, garlic, and tofu (or soybeans). After further adjusting for potentially anticarcinogenic constituents of these foods, high carotenoid vegetables, cruciferous vegetables, garlic, and tofu (or soybeans) remained inversely associated with polyps. These findings support the hypothesis that high intake of vegetables, fruits, or grains decreases the risk of polyps and suggest that any protective effects might reflect unmeasured constituents in these foods.

Adenomatous Polyposis Coli↗

PubMed1996

Plasma ferritin, iron intake, and the risk of colorectal polyps.

High iron exposure has been associated with colorectal neoplasia in several studies. The authors investigated plasma ferritin, an indicator of iron stores, and iron intake as risk factors for adenomatous polyps, intermediate markers for colorectal cancer. During 1991-1993, they collected fasting blood samples from and administered questionnaires to men and women 50-75 years old who visited free sigmoidoscopy clinics at a health maintenance organization. Data from 965 subjects (467 cases, 498 controls) were analyzed. Compared with those who had low-normal plasma ferritin concentrations (73-141 micrograms/liter), those with elevated concentrations ( > 289 micrograms/liter) had a multivariate-adjusted odds ratio of 1.5 (95% confidence interval (CI) 1.0-2.3) after excluding subjects with possible non-iron-related elevations in ferritin. Compared with subjects consuming an adequate amount of iron (11.6-13.6 mg/day), multivariate-adjusted odds ratios were 1.6 (95% CI 1.1-2.4) for < 11.6 mg/day and 1.4 (95% CI 0.9-2.0) for > 27.3 mg/day. These results provide further support for a weak positive association between iron exposure and colorectal polyps.

Aged↗

PubMed1996

Mortality associated with low plasma concentration of beta carotene and the effect of oral supplementation.

OBJECTIVE: To examine the relationship between beta carotene plasma concentration and beta carotene supplementation and risk of death from major disease causes. DESIGN: Cohort study of plasma concentrations; randomized, controlled clinical trial of supplementation. SETTING: Medical school-affiliated dermatology practices. PATIENTS: A total of 1188 men and 532 women with mean age of 63.2 years, who had enrolled in a randomized clinical trial of beta carotene supplementation to prevent nonmelanoma skin cancer. INTERVENTION: Oral beta carotene, 50 mg per day for a median of 4.3 years. MAIN OUTCOME MEASURES: All-cause mortality and mortality from cardiovascular disease and cancer. RESULTS: During a median follow-up period of 8.2 years, there were 285 deaths. Persons whose initial plasma beta carotene concentrations were in the highest quartile (>0.52 micromol/L [27.7 microg/dL]) had a lower risk of death from all causes (adjusted relative rate [RR], 0.52; 95% confidence interval [CI] 0.44 to 0.87) and from cardiovascular diseases (adjusted RR, 0.57; 95% CI, 0.34 to 0.95) compared with persons with initial concentrations in the lowest quartile (<0.21 micromol/L [11.2 microg/dL]). Patients randomly assigned to beta carotene supplementation showed no reduction in relative mortality rates from all causes (adjusted RR, 1.03; 95% CI, 0.82 to 1.30) or from cardiovascular disease (adjusted RR, 1.16; 95% CI, 0.82 to 1.64). There was no evidence of lower mortality following supplementation among patients with initial beta carotene concentrations below the median for the study group. CONCLUSIONS: These analyses provide no support for a strong effect of supplemental beta carotene in reducing mortality from cardiovascular disease or other causes. Although the possibility exists that beta carotene supplementation produces benefits that are too small or too delayed to have been detected in this study, noncausal explanations should be sought for the association between plasma concentrations of beta carotene and diminished risk of death.

Administration, Oral↗

PubMed1996

A case-control study of reproductive variables, alcohol, and smoking in premenopausal bilateral breast cancer.

Premenopausal bilateral breast cancer is characterized by a strong family risk, and, consequently, a high probability that inherited susceptibility genes may be segregating in these families. Determining whether risk factors that affect other breast cancer cases have a similar effect in the etiology of bilateral breast cancer is of interest. Therefore, as part of an ongoing genetic-epidemiologic study of premenopausal bilateral breast cancer, we conducted a case-control analysis of reproductive variables, benign breast disease, alcohol, and smoking. Cases had premenopausal bilateral breast cancer, and their unaffected sisters served as controls. A set of reproductive variables--including earlier age at menarche, nulliparity, and late age at first full term pregnancy--appeared to increase the risk of breast cancer; the corresponding confidence limits, however, were wide and straddled the null. In addition, other variables associated with increased premenopausal bilateral breast cancer risk were: use of oral contraceptives, history of benign breast disease, and high alcohol consumption. We found no positive association for smoking. Nulliparity and late age at first full-term pregnancy appeared to have different effects in women with family histories of breast cancer than in women without such a history. We detected no substantial effect modification for the other risk factors. In general, risk factors previously identified for breast cancer (usually postmenopausal, unilateral cases) appear also to increase the risk for premenopausal, bilateral breast cancer.

Age Factors↗

PubMed1996

A seroprevalence and descriptive epidemiological study of malaria among Indian tribes of the Amazon basin of Brazil.

Data on the seroprevalences of Plasmodium falciparum, P. vivax, and P. malariae in four isolated Indian tribes of the Amazon basin in Brazil, as determined by IFAT, were re-analysed. Age-, sex- and tribe-specific geometric mean antibody titres and externally standardized prevalence ratios were calculated for each parasite species. Correlation coefficients and prevalence odds ratios were also calculated for multiple infections with different combinations of the three Plasmodium species. Titres of all but one of the antibodies studied were similar in males and females; titres of antibodies to the blood stages of P. malariae were slightly higher in females than in males. Titres of antibodies to all three Plasmodium species increased with subject age, and this age effect was not confounded by sex or tribal differences. There were striking differences between tribes, with the Parakana tribe having relatively low titres of antibodies against P. falciparum and P. malariae; these tribal effects were not confounded by sex or age differences between tribes. The results indicate that conditions conductive to the transmission of P. malariae exist in this region of the Amazon. The potential for zoonotic transmission of P. brasilianum, a parasite of monkeys which is morphologically similar to P. malarie, and the generally high rates of seropositivity to all three species of Plasmodium indicate that control measures which are adequate and applicable to the region studied need to be developed.

Adolescent↗

PubMed1996

Lack of association between the polyadenylation polymorphism in the NAT1 (acetyltransferase 1) gene and colorectal adenomas.

Smoking and a high intake of red meat are risk factors for colorectal tumors. These effects could be due to aromatic amine carcinogens. Individual susceptibility to aromatic amines has been related to acetylation phenotype, which plays a role in the bioactivation of arylamines. Polymorphisms in both N-acetyltransferase genes, NAT1 and NAT2, have been associated with an increased risk of colorectal tumors. We studied the NAT1*10 fast acetylator allele (1088 T-->A mutation) and distal adenomas in a sigmoidoscopy-based case-control study (441 cases, 484 controls). We found neither an increased adenoma prevalence in subjects homozygous or heterozygous for the NAT1*10 fast acetylator allele (odds ratio 1.04; 95% confidence interval 0.79-1.36), nor a gene-gene interaction between NA1 and NAT2 (P(interaction) = 0.59). Further NAT1 alleles must be considered for more conclusive results regarding the relevance of NAT1 activity to colorectal tumorigenesis.

Adenoma↗

PubMed1996

Alcohol and smoking in relation to the prevalence of adenomatous colorectal polyps detected at sigmoidoscopy.

Cigarette smoking has been associated with adenomatous polyps of the large bowel but not with increased risk of colorectal cancer. Giovannucci et al recently proposed a hypothesis to explain this inconsistency. A key testable aspect of the hypothesis is that smoking in the distant past increases the risk of large polyps. Questions also remain about the association between colorectal polyps and consumption of alcohol. To address these issues, we examined data from 488 cases with adenomatous polyps and 488 controls. Subjects were members of a prepaid health plan in Los Angeles who had a sigmoidoscopy in 1991-1993. As expected, the adjusted odds of polyps in current smokers compared with never-smokers was increased [odds ratio = 2.43; 95% confidence interval (CI) = 1.56-3.79]. For those who had smoked in the distant past (for example, 30 or more pack-years before 20 years ago), the adjusted odds of an adenoma > or = 1 cm, relative to nonsmokers, was 0.88 (95% CI = 0.23-3.42). The adjusted odds of polyps in those consuming > or = 46 gm per day of alcohol compared with nondrinkers was 1.50 (95% CI = 0.72-3.13). Although imprecise, these data do not support the hypothesis that past smoking increases the risk of large polyps, but our results indicate a weak association between alcohol use and risk of adenomatous polyps.

Adenomatous Polyps↗

PubMed1996

Agreement in alcohol consumption levels as measured by two different questionnaires.

OBJECTIVE: We evaluated the agreement in reported alcohol consumption between a standard food frequency questionnaire (FFQ) and a risk factor questionnaire (RFQ) developed for a genetic epidemiologic study of breast cancer. METHOD: The FFQ measured intake of alcoholic beverages by asking which of nine levels were consumed during a single time period. In contrast, the RFQ used open-ended questions to measure intake of alcoholic beverages during numerous time periods. Subjects (N = 765) completed both questionnaires at home. RESULTS: Mean daily alcohol consumption levels were consistently higher in the FFQ than in the RFQ; for example, the mean alcohol consumption for all subjects was 7.0 g/day in the FFQ versus 5.3 g/day in the RFQ. Moreover, the RFQ overestimated the number of nondrinkers relative to the FFQ. Nonetheless, the Spearman correlation coefficients between daily alcohol consumption levels as measured by the two questionnaires were relatively high: total alcohol, r = 0.72; beer, r = 0.69; wine, r = 0.69; and distilled spirits, r = 0.54. CONCLUSIONS: The reasonable agreement between these questionnaires supports the validity of historical alcohol consumption levels measured by the RFQ.

Adult↗

PubMed1996

Serum lipids and adenomas of the left colon and rectum.

Levels of serum lipids are partially determined by several established risk factors for colorectal cancer and are themselves potential risk factors for the disease. However, evaluating serum lipids as risk factors has proved problematic because metabolic events associated with malignant transformation or progression appear to alter serum lipid concentrations. Serum lipid concentrations are less likely to have altered in individuals with precancerous lesions, such as colorectal adenomas. During 1991-1993, we collected fasting blood samples from and provided questionnaires to men and women 50-75 years old, who visited sigmoidoscopy clinics at a health maintenance organization. Serum lipid concentrations from 486 cases with adenomas and 520 controls were analyzed. Compared to subjects in the lowest quintile of serum triglyceride concentrations, subjects in the highest quintile had an adjusted odds ratio of 1.5 (95% confidence interval, 1.0-2.2). The corresponding odds ratio for total cholesterol was 1.3 (0.9-1.9); for high-density lipoprotein cholesterol, it was 1.1 (0.7-1.6); and for low-density lipoprotein cholesterol, it was 1.1 (0.7-1.6). Further adjustment for potential confounding did not alter these results substantively, although determinants of serum triglycerides and high-density lipoprotein cholesterol (e.g., obesity, physical activity, and refined carbohydrate and alcohol intake) in this and other studies may not be sufficiently well measured to avoid residual confounding. Higher levels of serum triglycerides are associated with an increased risk of adenomatous polyps. Consistent with previous studies, serum cholesterol was not inversely related to the risk of colorectal polyps.

Adenoma↗

PubMed1996

Dietary intake of specific carotenoids and vitamins A, C, and E, and prevalence of colorectal adenomas.

We determined whether intakes of the main dietary carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein plus zeaxanthin, and lycopene) and of vitamins A, C, and E were associated with the prevalence of colorectal adenomas among male and female members of a prepaid health plan in Los Angeles who underwent sigmoidoscopy (n = 488 matched pairs). Participants, ages 50-74 years, completed a 126-item semiquantitative food-frequency questionnaire and a non-dietary questionnaire from 1991 to 1993. In the univariate-matched analysis, alpha-carotene, beta-carotene (with and without supplements), beta-cryptoxanthin, lutein plus zeaxanthin, vitamin A (with and without supplements), and vitamin C (with and without supplements) were associated with a decreased prevalence of colorectal adenomas. After adjustment for intake of calories, saturated fat, folate, fiber, and alcohol, and for current smoking status, body mass index, race, physical activity, and use of nonsteroidal anti-inflammatory drugs, only beta-carotene including supplements was inversely associated with adenomas (odds ratio (OR), 0.6; 95% confidence interval (CI), 0.41.1; trend, P= 0.04; ORs compare highest to lowest quartiles0; vitamin C showed a weaker inverse association (OR, 0.8; 95% CI, 0.5-1.5; trend, P = 0.08); and the remaining compounds were no longer clearly associated with risk. After including beta-carotene with supplements and vitamin C simultaneously in the mutivariate model, the association of beta-carotene with supplements with adenomas was weakened (OR, 0.8; 95% CI, 0.5-1.3; trend P = 0.15), and vitamin C was no longer associated with risk. These data provide only modest support for a protective association of beta-carotene with colorectal adenomatous polyps.

Adenoma↗

PubMed1995

Acetylation polymorphism and prevalence of colorectal adenomas.

Polymorphic N-acetyltransferase (NAT2), an enzyme present in the colon, may effect incidence of colon cancer. Individuals with NAT2 fast acetylator genotypes may have higher colon cancer risks due to faster conversion of certain carcinogens to mutagens. We determined NAT2 genotypes in 447 subjects with distal colon adenomas and in 487 controls. No significant increase in adenoma prevalence among fast acetylators was observed. However, there was a suggestion of ethnic differences in NAT2 effects. For example, white fast acetylators potentially had slightly increased risks for adenomas (odds ratio, 1.29; 95% confidence interval, 0.90-1.84), whereas fast acetylation was potentially protective among blacks (odds ratio, 0.64; 95% confidence interval, 0.32-1.28). The apparent difference between blacks and whites may simply reflect random variation around an overall null effect, or it could represent a real difference. There was preliminary evidence for a possible interaction between NAT2 and the glutathione transferase M1 null genotype. Smokers' adenoma prevalence was 10-fold higher for fast acetylators with the null genotype compared to slow acetylators without the null genotype. Large, multiethnic populations and analysis of combinations of genes for carcinogen metabolism may be needed to further assess the role of NAT2 in colorectal tumorigenesis.

Acetylation↗

PubMed1995

Glutathione transferase (GSTM1) null genotype, smoking, and prevalence of colorectal adenomas.

Colorectal cancer is caused by environmental exposures and genetic predisposition. However, little is known of hereditary factors that influence development of common, non-Mendelian forms of this cancer. Interactions among carcinogen exposure, hereditary variants of enzymes involved in carcinogen metabolism, and other host factors may play a role. Genetic polymorphisms of carcinogen metabolism, such as the glutathione transferase M1 (GSTM1) null genotype, are thus possibly related to cancer risk. The GSTM1 enzyme detoxifies mutagens formed from polycyclic aromatic hydrocarbons which are found in tobacco smoke. We analyzed GSTM1 genotypes and smoking among 488 controls and 446 individuals with a first time diagnosis of colorectal adenomas which are precursors to cancer. Subjects were from two Kaiser Permanente sigmoidoscopy clinics in southern California. We observed no overall effect of the GSTM1 null genotype on the risk for colorectal adenomas (odds ratio, 0.85; 95% confidence interval = 0.65-1.10). The odds ratio for smokers with the null genotype was 2.07 (95% confidence interval = 1.14-3.77) when compared to "never smokers" without the null genotype. Using this same reference group, the odds ratio for smokers without the null genotype was 1.73 (95% confidence interval = 1.03-2.90). These two odds ratios were not significantly different (P = 0.30).

Adenoma↗

PubMed1995

Early adult body weight, body mass index, and premenopausal bilateral breast cancer: data from a case-control study.

Previous studies using current or recent adult body weight and body mass index are inconclusive as to a possible effect of increased body mass on premenopausal breast cancer incidence. Only five studies have presented data on early adult body mass, and no study has reported these data for premenopausal bilateral breast cancer. Because premenopausal bilateral breast cancer is assumed to be partly genetic and partly environmental in origin, it is crucial to identify possible modifiable risk factors for this cancer. We present data on early adult body weight and body mass (Quetelet Index, QI) from a case-control study of 142 premenopausal bilateral breast cancer cases from Los Angeles County, California, Connecticut, and Quebec, Canada, and 229 sister controls. The odds ratio (and 95% confidence interval) of premenopausal breast cancer adjusted for age, education, alcohol consumption, and oral contraceptive use was 0.7 (0.3-1.4) for women in the highest tertile of QI at age 18. The results do not suggest that elevated body mass index at a young age increases the risk of premenopausal bilateral breast cancer, but lend only weak support to the hypothesis of an inverse association between body mass index and premenopausal breast cancer.

Adolescent↗

PubMed1995

A meta-analysis of body mass index and risk of premenopausal breast cancer.

Increased body mass index (BMI) has been found to be associated with elevated risk of postmenopausal breast cancer. Whether BMI is related to premenopausal breast cancer has not yet been established. We performed a meta-analyses of data from 23 studies that provided information on BMI and incidence of premenopausal breast cancer. Overall, the data support a modest inverse association. For a BMI difference of 8 kg per m2, that is, the difference between a thin person and someone who is morbidly obese, the random effects estimate of the rate ratio from the four cohort studies was 0.70 [95% confidence interval (CI) = 0.54-0.91], and the random effects estimate of the odds ratio from the 19 case-control studies was 0.88 (95% CI = 0.76-1.02). Because of substantial heterogeneity among the study-specific estimates, however, we also examined the influence of certain aspects of study design. Case-control studies with community controls had a more inverse association, whereas case-control studies that interviewed cases shortly after diagnosis applied the same exclusion criteria to cases and controls, or with confounder adjustment beyond age had a more positive association between BMI and breast cancer. Possible reasons for the discrepancies among the case-control studies are discussed.

Adult↗

PubMed1994

A clinical trial of antioxidant vitamins to prevent colorectal adenoma. Polyp Prevention Study Group.

BACKGROUND: People who consume a diet high in vegetables and fruits have a lower risk of cancer of the large bowel. Antioxidant vitamins, which are present in vegetables and fruits, have been associated with a diminished risk of cancers at various anatomical sites. We conducted a randomized, controlled clinical trial to test the efficacy of beta carotene and vitamins C and E in preventing colorectal adenoma, a precursor of invasive cancer. METHODS: We randomly assigned 864 patients, using a two-by-two factorial design, to four treatment groups, which received placebo; beta carotene (25 mg daily); vitamin C (1 g daily) and vitamin E (400 mg daily); or the beta carotene plus vitamins C and E. In order to identify new adenomas, we performed complete colonoscopic examinations in the patients one year and four years after they entered the study. The primary end points for analyses were new adenomas identified after the first of these two follow-up examinations. RESULTS: Patients adhered well to the prescribed regimen, and 751 completed the four-year clinical trial. There was no evidence that either beta carotene or vitamins C and E reduced the incidence of adenomas; the relative risk for beta carotene was 1.01 (95 percent confidence interval, 0.85 to 1.20); for vitamins C and E, it was 1.08 (95 percent confidence interval, 0.91 to 1.29). Neither treatment appeared to be effective in any subgroup of patients or in the prevention of any subtype of polyp defined by size or location. CONCLUSIONS: The lack of efficacy of these vitamins argues against the use of supplemental beta carotene and vitamins C and E to prevent colorectal cancer. Although our data do not prove definitively that these antioxidants have no anticancer effect, other dietary factors may make more important contributions to the reduction in the risk of cancer associated with a diet high in vegetables and fruits.

Adenomatous Polyps↗

PubMed1994

Hierarchical regression analysis applied to a study of multiple dietary exposures and breast cancer.

Hierarchical regression attempts to improve standard regression estimates by adding a second-stage "prior" regression to an ordinary model. Here, we use hierarchical regression to analyze case-control data on diet and breast cancer. This regression yields semi-Bayes relative risk estimates for dietary items by using a second-stage model to pull estimates toward each other when the corresponding variables have similar levels of nutrients. Unlike classical Bayesian analysis, however, no use is made of previous studies on nutrient effects. Compared with results obtained with one-stage conditional maximum-likelihood logistic regression, our hierarchical regression model gives more stable and plausible estimates. In particular, certain effects with implausible maximum-likelihood estimates have more reasonable semi-Bayes estimates.

Bayes Theorem↗

PubMed1993

Linkage analysis of DRD2, a marker linked to the ataxia-telangiectasia gene, in 64 families with premenopausal bilateral breast cancer.

Recent reports suggest that subjects who are heterozygous for the ataxia-telangiectasia gene are at increased risk of breast cancer. We conducted linkage analyses of 64 families with premenopausal bilateral breast cancer using DRD2, a marker linked to the ataxia-telangiectasia locus at 11q22-23. We assumed a model with dominant transmission of breast cancer. Lod scores summed over all families provided strong evidence against tight linkage (e.g., a lod score of -6.08 at theta = 0.00001), although a single family provides suggestive evidence of tight linkage to DRD2. Evidence against linkage to 11q was strongest among families that may involve the BRCA1 breast cancer susceptibility gene on 17q21. However, we did not observe evidence of linkage to 11q among the remaining subgroup with neither a family history of ovarian cancer nor the appearance of linkage to 17q21.

Adult↗

PubMed1993

Dietary patterns associated with a low-fat diet in the national health examination follow-up study: identification of potential confounders for epidemiologic analyses.

To identify systematically the nutrient and food group intakes associated with a low-fat diet, the authors used the detailed dietary information collected from 10,306 individuals aged 32-86 years in the 1982-1984 National Health Epidemiologic Follow-up Study. Intakes of vitamin C and percentages of calories from carbohydrates, dietary fiber, poultry, low-fat dairy products, fruits, vegetables, cereals, and whole grains were markedly higher, while intakes of protein, total fat, saturated fat, oleic and linoleic acids, cholesterol, sodium, all red meats, high-fat dairy products, eggs, nuts, white bread, fried potatoes, desserts, fats, and oils were much lower in the quartile with the lowest percentage of calories from fat. These dietary patterns associated with a low-fat diet were essentially constant across strata of age, sex, race, and socioeconomic status. This study suggests that individuals on a low-fat diet substitute certain carbohydrate-rich foods such as fruits and vegetables for fat. Given these associations between low-fat diets and other dietary factors independently associated with certain cancers, these dietary factors should be considered potential confounders in studies of dietary fat and these cancers.

Adult↗