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L Le Marchand

Publications and source records attributed to L Le Marchand.

At least 55 records · Page 3Linked to original sources
PubMed1994

CYP1A1 genetic polymorphisms and in situ colorectal cancer.

Numerous studies have associated colorectal adenoma with smoking and large bowel cancer with consumption of foods potentially containing polycyclic aromatic hydrocarbons. Enhanced metabolic activation of polycyclic aromatic hydrocarbons has recently been observed in homozygotes for a MspI mutation in the 3'-end of CYP1A1. We conducted a population-based case-control study to investigate whether CYP1A1 polymorphisms were related to colorectal cancer risk. Using polymerase chain reaction-based methods, we assessed the frequency of the MspI polymorphism in the 3'-end of CYP1A1 and another mutation in exon 7 of the gene (Ile-Val polymorphism) among 43 patients with in situ adenocarcinoma of the large bowel and 129 population controls. Homozygosity for the MspI mutant genotype was found to be positively associated with in situ colorectal cancer in Japanese (P = 0.008) and Hawaiians/part-Hawaiians (P < 0.001), whereas the study lacked power to detect a similar association in Caucasians. The odds ratio for the homozygous variant genotype compared to the heterozygous and wild-type genotypes was 7.9 (95% confidence interval, 1.4-44.4) in Japanese. A similar association was suggested for the exon 7 mutation homozygosity in Japanese, as the two polymorphisms are in genetic disequilibrium. Thus, this study suggests a potentially important role for CYP1A1 and polycyclic aromatic hydrocarbons in the etiology of colorectal cancer in populations with a high gene frequency.

Adult↗
PubMed1994

Effects of micronutrients and antioxidants on lipid peroxidation in human plasma and in cell culture.

Plasma levels of triglycerides, retinol, cholesterol, lipid-phase antioxidants (alpha-, gamma-tocopherols, beta-carotene, alpha-carotene, lycopene, beta-cryptoxanthin and lutein/zeaxanthin), and thiobarbituric acid-reactive substances (TBA-RS), as an indicator of lipid peroxidation, were repeatedly determined in nine individuals over a 3-month period. Levels of TBA-RS were positively correlated with plasma triglycerides and gamma-tocopherol, and negatively correlated with plasma carotenoids. These results were consistent with in vitro cell culture studies which showed increased TBA-RS for cells supplemented with linolenic acid and decreased levels when treated with beta-carotene. We conclude that TBA-RS measurements in plasma accurately reflect the level of peroxidizable substrate as modified by the presence of a variety of dietary antioxidants, particularly carotenoids. Although the inter- and intra-individual variabilities for TBA-RS are comparable with the micronutrients and antioxidants measured in this study, high interassay variability and the strong association with the more commonly measured plasma triglycerides suggest the TBA-RS assay to be of limited use in epidemiologic studies. However, this assay does appear to be useful in cell culture studies where experimental conditions can be better controlled. Low ratios of inter- to intra-individual variability in some of the plasma micronutrient and lipid-phase antioxidants measured suggest that multiple samples may be required to characterize individuals in studies evaluating the relation between these plasma constituents and disease incidence.

Animals↗
PubMed1994

Animal fat consumption and prostate cancer: a prospective study in Hawaii.

Whereas case-control studies have been very consistent in suggesting a positive association between intake of dietary fat, especially animal fat, and prostate cancer, the results from past cohort studies have been mostly inconclusive. In this study, we evaluated consumption of high-fat animal products, raw vegetables, and fresh fruits, as well as obesity, smoking, and drinking, in relation to subsequent occurrence of prostate cancer. We studied a cohort of 20,316 men of various ethnicities interviewed between 1975 and 1980 in Hawaii. As of December 1989, 198 incident cases with invasive prostate cancer were identified by computer-assisted linkage of this cohort to the statewide Surveillance, Epidemiology, and End Results registry. Relative risks (RRs) for prostate cancer computed by proportional hazards regression were elevated for intake of beef [RR for highest to lowest tertile of intake = 1.6; 95% confidence interval (CI) = 1.1-2.4] and milk (RR = 1.4; 95% CI = 1.0-2.1), and for a summary variable for intake of high-fat animal products (RR = 1.6; 95% CI = 1.0-2.4). Weight was not consistently associated with prostate cancer, but there was an association with height (> 167 cm) (RR = 1.8; 95% CI = 1.0-3.2 for the third and fourth quartiles relative to the lowest quartile in height). These associations were stronger in men diagnosed before age 72.5 years. The risk estimates for raw vegetable and fresh fruit intakes were close to 1.0. Smoking and alcohol drinking appeared to be unrelated to risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Use of breath hydrogen and methane as markers of colonic fermentation in epidemiological studies: variability in excretion.

Breath hydrogen and methane are specific end products of colonic fermentation, a process which may play a protective role against colon cancer. To assess the possibility of using these markers in epidemiological studies, we characterized the intra- and intersubject variability of breath hydrogen and methane excretion over 15 consecutive days among 32 men and women of various ethnic backgrounds (16 Asians, 8 Caucasians, 8 Hawaiians). Participants were asked to collect four end-expiratory samples each day, which we had shown previously would optimally characterize daily hydrogen excretion. There was substantial within-subject variation in breath hydrogen over the study, although breath methane levels were more constant over time. We found that about 4 days of measurement of breath hydrogen and 1 day of measurement for breath methane are required to correctly characterize individuals according to their long-term excretion of these gases. This was true for Asians and non-Asians. Although breath methane appears to be more practical to measure, it is a less sensitive marker of colonic fermentation than breath hydrogen. Whereas all subjects excreted hydrogen, only 28% of the subjects excreted methane, and methane excretor status of a few participants varied during the study. Because the breath test is noninvasive and reliable, we tested the multiple day collection protocol among colon cancer patients and controls and found it to be well accepted. We conclude that it is practical to measure breath hydrogen and methane in large epidemiological studies conducted at the individual level. The potential use for these markers is discussed.

Aged↗
PubMed1993

Assessment of carotenoid intakes in humans.

The availability of new food composition carotenoid values for fruits and vegetables increases our ability to test hypotheses concerning the role of antioxidant nutrients and cancer risk. To estimate the usual carotenoid intakes, a quantitative diet history covering a one-year period is recommended for epidemiologic studies on diet and cancer. The particular food items in the diet history questionnaire should be representative of the eating patterns of the study population, should contribute more than 85% of the individual carotenoid intakes, and should distinguish between the high and low consumers of particular carotenoids.

Carotenoids↗
PubMed1993

Breath hydrogen and methane in populations at different risk for colon cancer.

Results from laboratory and clinical studies have suggested that fermentation in the large bowel may play a protective role against colon cancer. Hydrogen and methane are end-products of colonic fermentation that are absorbed into the bloodstream and excreted via expired air in the breath. Thus, breath levels of hydrogen and methane have been used as markers for this process. Breath levels of these gases were compared among 10 ethnic and sex groups that exhibit marked differences for colon cancer risk in Hawaii. Four end-expiratory breath samples were used to characterize daily excretion of hydrogen and methane in a population-based sample of 244 men and women. There was no significant difference in breath hydrogen or methane by sex or age. Hawaiians produced significantly more hydrogen than Filipinos, and Hawaiians and Caucasians more methane than the 3 Asian groups. These differences did not correlate with risk of colon cancer among these ethnic populations.

Adult↗
PubMed1993

Seroepidemiological survey of HTLV-I infection in French Polynesia, Cook Islands and Fiji.

Different population groups of French Polynesia, Cook Islands and Fiji were screened for Human T-Lymphotropic Virus type I (HTLV-I) antibodies. Among 1487 individuals sampled in French Polynesia, twelve were considered Western Blot (WB) indeterminate and one was considered WB-positive for HTLV-I infection. This positive subject originated from France and was a blood donor. Out of 196 Polynesians of the Cook Islands, one was WB-indeterminate. Among populations sampled in Fiji, one of 222 Melanesians was found WB-indeterminate and one of 211 Indians was WB-indeterminate.

Adolescent↗
PubMed1992

An analytical method for assessing patterns of familial aggregation in case-control studies.

This paper describes an analytical method that is used to assess patterns of disease aggregation within family based on family history information collected in case-control studies. In such a study, cases and controls are thought of as probands whose relatives are identified, and relatives' phenotypes and other covariates such as age, sex, and genealogical relationship with the probands are recorded. By modeling the dependence of relatives' phenotypes on case-control status and other covariates, this method yields adjusted odds ratios that quantify familial aggregation. The estimated standard errors are obtained for statistical inference since the method acknowledges the potential correlations between relatives' phenotypes by using the estimating equations technique. In population-based case-control studies, the estimates and statistical inferences are generalizable to the general population. To illustrate this method, we analyzed a case-control study of colorectal cancer involving 5,190 relatives of 792 cases and 4,478 relatives of 680 population-based controls conducted in Hawaii. Although detailed results will be presented elsewhere, the colorectal cancer was found to aggregate within family with an odds ratio of 2.74 (95% confidence interval (CI): 1.78-4.21). Among parents, the odds ratio for familial aggregation was 2.38 (95% CI: 1.25-4.54). The corresponding value for siblings was 3.09 (95% CI: 1.87-5.11). It was also found that the odds ratio increases from about 2.00 for relatives of the probands who were 50 years or older to 7.66 and 12.84 for relatives of the probands who were between 40 and 50 years and under 40 years, respectively, suggesting that the familial aggregation of colorectal cancer decreases as probands' age increases.

Adult↗
PubMed1992

Obesity in youth and middle age and risk of colorectal cancer in men.

To investigate an association between colon cancer and obesity during early adulthood--a potentially important period in the etiology of this disease--the authors assembled, by computer linkage, a population-based historical cohort of 52,539 men born between 1913 and 1927 residing in Hawaii (USA), for whom weight and height had been recorded in 1942-43 and 1972. Linkage of this cohort to the Hawaii Tumor Registry resulted in the identification of 737 incident cases of colorectal cancer for 1972-86. An average of 3.8 cancer-free controls were matched to each case on month and year of birth and ethnicity of the parents. A case-control analysis in each anatomic subsite of the large bowel revealed that both early and middle-age body mass increased the risk of sigmoid cancer in men in a dose-dependent fashion. The odds ratios (OR) for sigmoid cancer for the highest compared with the lowest tertiles of Quetelet index were: 2.1 (95 percent confidence interval [CI] = 1.4-3.2) and 1.7 (CI = 1.1-2.5), at ages 15-29 and in prediagnostic years, respectively. These associations were additive and independent of socioeconomic status. Men who were above the median Quetelet index in 1942 and 1972 had an OR of 2.7 (CI = 1.8-4.0), compared with those who were below the median in both periods. This study provides further evidence for an association of obesity with colon cancer in men and suggests that this association is limited to the sigmoid colon and may be related to both early and late events of colon carcinogenesis.

Adolescent↗
PubMed1992

Dietary factors in lung cancer prognosis.

A hypothesis-generating analysis of the role of diet on survival was conducted among a sample of 463 men and 212 women with histologically-confirmed lung cancer. Interview information was obtained from two population-based case-control studies of lung cancer conducted on the Island of Oahu, Hawaii, between 1979 and 1985. The interview consisted of a quantitative dietary history to assess the usual intake of foods 1 year prior to diagnosis, a complete tobacco history, and other demographic and lifestyle information. Records from the Hawaii Tumor Registry were reviewed for data on stage, histology, and follow-up status of these patients. A food group analysis showed a significant reduction in the risk of death with increasing consumption of all vegetables combined among women (P for trend = 0.03), but not among men. The covariate-adjusted median survival times for women from the highest to the lowest quartiles of vegetable intake were 33, 21, 15, and 18 months, respectively. The results also suggested an association of fruit intake and survival among women (P for trend = 0.02), although a similar effect was not found among men. Increased consumption of certain foods, such as tomatoes and oranges among men, and broccoli and, perhaps, tomatoes among women, appeared to improve survival. This exploratory analysis provides mixed indications that certain components of vegetables and fruits may prolong survival in lung cancer patients.

Adult↗
PubMed1992

Use of breath hydrogen and methane as markers of colonic fermentation in epidemiologic studies: circadian patterns of excretion.

Fermentation in the large bowel has been postulated to play a protective role against colon cancer. Hydrogen and methane are end products of this fermentation process and are absorbed into the bloodstream and excreted via expired air in the breath. Breath levels of hydrogen and, to a lesser extent, methane correlate strongly with colonic fermentation and may serve as useful biomarkers for this process. In a preliminary study to assess the usefulness of these two markers in epidemiologic studies, we followed the hourly excretion of the two gases in expired alveolar air for 48 hr in 20 healthy subjects, using a Quintron gas chromatograph equipped with a solid-state detector specific for reducing gases. All subjects excreted hydrogen, but 71% did not excrete methane. Possible atmospheric contamination of the samples was corrected for on the basis of breath carbon dioxide levels. A clear circadian pattern of excretion was observed for breath hydrogen, with a decrease during the early morning followed by a progressive increase during the rest of the day. Methane excretion was constant throughout the day. This study shows that four samples collected at convenient times (0600, 1300, 1800, and 2200 hr) are optimal to characterize individuals by their breath excretions of hydrogen and methane during a 24-hr period.

Biomarkers↗
PubMed1992

[Cancer in Japanese migrants to Hawaii: interaction between genes and environment].

This paper describes the progressive changes in cancer incidence that have been observed among Japanese after their migration to Hawaii. It reviews descriptive and analytic epidemiologic data suggesting a role for genetic susceptibilities in explaining the high risk of Japanese for colon cancer and their low risk for lung cancer, when compared to Caucasians. Differences in certain pharmacogenetic polymorphisms may explain these risk patterns. This research may lead to a better characterization of cancer risk at the individual level and, consequently, to improved methods of prevention.

Colonic Neoplasms↗
PubMed1991

Early-age body size, adult weight gain and endometrial cancer risk.

To further characterize the association of obesity and endometrial cancer, in particular with regard to the role of early-age obesity and adult weight gain, the authors assembled by computer linkage a population-based historical cohort of 30,266 women born between 1913 and 1932, for whom weight and height had been recorded in 1942-43 and 1972. Linkage of this cohort to the Hawaii Tumor Registry resulted in the identification of 214 (mainly post-menopausal) incident cases of endometrial cancer for 1972-1986. An average of 37 cancer-free controls were matched to each case on month and year of birth and ethnicity. A case-control analysis, conducted in each 5-year birth cohort, revealed no clear association of endometrial cancer with weight, height or body mass at ages 10 to 29 years. However, positive associations with adult body weight and gain in body mass since 1942 were observed for women diagnosed at age 60 or older. This association with obesity was strongest in women whose body mass was below the median in 1942 and equal to or above the median in 1972. No association with body size was detected in women diagnosed before age 60. Parity, age at first birth and socioeconomic indicators for 1942 and 1972 did not confound the analysis. These findings suggest that obesity affects the late stages of endometrial carcinogenesis, and the possibility that one or more determinants of weight gain may be independently associated with endometrial cancer risk.

Aged↗
PubMed1991

Vegetable and fruit consumption in relation to prostate cancer risk in Hawaii: a reevaluation of the effect of dietary beta-carotene.

This is a further analysis of a case-control study of 452 prostate cancer cases and 899 population controls that was conducted in 1970-1983 among the multiethnic population of Hawaii. Because a previous analysis had shown a positive association with intake of beta-carotene, a nutrient presently being tested for chemoprevention, the authors reexamined the data for consistency among the main food sources of beta-carotene. Vegetables and fruits containing other phytochemicals suspected to be cancer inhibitors were also examined. With the exception of papaya, which was positively associated with risk among men aged 70 years and older, consumption of other yellow-orange fruits and vegetables, tomatoes, dark green vegetables, and cruciferous vegetables was not associated with prostate cancer risk. These results suggest that: 1) the positive association with beta-carotene intake among older men that the authors previously reported was essentially due to the greater papaya consumption of cases compared with controls; and 2) intake of beta-carotene, lycopene, lutein, indoles, phenols, or other phytochemicals is not associated with prostate cancer risk.

Aged↗
PubMed1991

Lifetime occupational physical activity and prostate cancer risk.

The authors compared the lifetime occupational physical activity of 452 prostate cancer cases identified through the population-based Hawaii Tumor Registry and 899 population controls interviewed from 1981 to 1983. Each job reported was classified into one of five levels of physical activity using published sources. Among men aged 70 years or older, a negative association was found between prostate cancer risk and proportion of life spent in jobs involving only sedentary or light work. Compared with men never employed in such jobs, men who spent more than 54% of their life in these jobs had an odds ratio of 0.5 (95% confidence interval 0.3-0.9). This negative association was dose-dependent, consistent across ethnic groups, and unrelated to socioeconomic status, dietary risk factors, or job-related chemical exposures. The findings for younger men were less clear, but not inconsistent with those for older men. Surprisingly, no association was found with years spent in moderately active or very active jobs in either age group. Although inconclusive, these results suggest that physical activity may be positively associated with the risk of prostate cancer, but this association is likely to be weak and indirect.

Age Factors↗
PubMed1991

Dietary patterns of female nonsmokers with and without exposure to environmental tobacco smoke.

The relationship of passive smoking to diet was examined in 82 female nonsmokers who provided a quantitative diet history in 1986. Exposure to environmental tobacco smoke (ETS) was assessed by urinary cotinine measurement. Mean values for each dietary variable, adjusted for age, ethnicity, education, and last week's ethanol intake, were compared among unexposed women and women with low or high ETS exposure. Linear relationships with amount of ETS exposure were also sought. Intakes of beta-carotene and cholesterol were found to be inversely related to ETS exposure. Since these nutrients have been associated with lung cancer risk, they are potential confounders of the passive-smoking/lung-cancer relationship. Although we estimate the confounding effect of these dietary factors to be modest, they should be measured carefully in future studies of this relationship.

Age Factors↗
PubMed1991

Ethnic variation in breast cancer survival: a review.

Intercountry, as well as intracountry, survival comparisons have revealed some differences in breast cancer survival among various ethnic populations. Most of these differences are probably explained by factors related to socioeconomic status. However, the well documented survival advantage of Japanese patients compared to Caucasian patients remains unexplained. Some recent studies suggest an adverse prognostic effect for obesity. Although still inconclusive, these findings raise the possibility that the better survival of Japanese patients may be in part related to their lower mean body weight. An effect of the lower fat intake of the Japanese in explaining their breast cancer survival advantage has little support at present, but, like the obesity hypothesis, deserves further study.

Adult↗