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M L Slattery

Publications and source records attributed to M L Slattery.

At least 55 records · Page 3Linked to original sources
PubMed1999

BAT-26 and BAT-40 instability in colorectal adenomas and carcinomas and germline polymorphisms.

Analysis of the mononucleotide repeats BAT-26 and BAT-40 has reportedly revealed significant microsatellite instability in sporadic colorectal adenomas, whereas studies with dinucleotide and tetranucleotide repeats have not. In addition, BAT-26 has been reported to be "quasimonomorphic" in the germline. We evaluated BAT-26 and BAT-40 in a series of colorectal tumors previously analyzed with a panel of tetranucleotide repeats. Instability in BAT-26 or BAT-40 was significantly associated with tetranucleotide repeat instability in sporadic adenomas and carcinomas (P < 0.0001) and was similarly much less common in adenomas than in carcinomas. Germline polymorphisms in both BAT-40 and BAT-26 were identified, and the frequency of BAT-26 polymorphisms was significantly higher in African Americans than in Caucasians (7.7% versus 0.08%, P < 0.001). BAT-26 and BAT-40 may be very useful in evaluating instability in small tumors, as sufficient DNA to be amplified by large panels of microsatellites is not always available from such lesions. Polymorphisms in these microsatellites, however, limit their utility in determinations of microsatellite instability without corresponding normal DNA.

3-Hydroxysteroid Dehydrogenases↗
PubMed1999

Does nutritionist review of a self-administered food frequency questionnaire improve data quality?

OBJECTIVE: This study sought to evaluate the benefit of utilizing a nutritionist review of a self-administered food frequency questionnaire (FFQ), to determine whether accuracy could be improved beyond that produced by the self-administered questionnaire alone. DESIGN: Participants randomized into a dietary intervention trial completed both a FFQ and a 4-day food record (FR) at baseline before entry into the intervention. The FFQ was self-administered, photocopied and then reviewed by a nutritionist who used additional probes to help complete the questionnaire. Both the versions before nutritionist review and after nutritionist review - were individually compared on specific nutrients to the FR by means, correlations and per cent agreement into quintiles. SETTINGS AND SUBJECTS: Three hundred and twenty-four people, a subset of participants from the Polyp Prevention Trial - a randomized controlled trial examining the effect of a low-fat, high-fibre, high fruit and vegetable dietary pattern on the recurrence of adenomatous polyps - were recruited from clinical centres at the University of Utah, University of Buffalo, Memorial Sloan Kettering Cancer Center in New York and Kaiser Permanente Medical Program in Oakland. RESULTS: Reviewing the FFQ increased correlations with the FR for every nutrient, and per cent agreement into quintiles for all nutrients except calcium. Energy was underestimated in both versions of the FFQ but to a lesser degree in the version with review. CONCLUSIONS: One must further evaluate whether the increases seen with nutritionist review of the FFQ will enhance our ability to predict diet-disease relationships and whether it is cost-effective when participant burden and money spent utilizing trained personnel are considered.

Data Collection↗
PubMed1999

Hormone replacement therapy and improved survival among postmenopausal women diagnosed with colon cancer (USA).

OBJECTIVES: Hormone replacement therapy (HRT) has been inversely associated with colon cancer incidence in several epidemiologic studies. In this study we used data from a population-based incident case-control study of colon cancer to evaluate the role of HRT use in survival after diagnosis with colon cancer. METHODS: Data from 815 postmenopausal women living in Utah, California, and Minnesota diagnosed between 1 September 1991 and 30 September 1994 were used to examine associations between HRT and survival. RESULTS: After adjusting for age at time of diagnosis, stage of disease at time of diagnosis, study center, and body mass index (BMI), we observed that women who had ever used HRT had a 30% lesser probability of dying of any cause and a 40% lower probability of dying from colon cancer specifically during the follow-up period. Further evaluation by years of HRT use showed that those who had used HRT for 4 or more years had the lowest risk of dying of colon cancer (hazard rate ratio 0.5, 95% confidence interval 0.3-0.9). Evaluation of other lifestyle variables with HRT use did not show significant confounding or effect modification. CONCLUSIONS: These findings suggest that HRT use may improve short-term survival after diagnosis with colon cancer; there is no suggestion that HRT use is detrimental to survival.

Adult↗
PubMed1999

Cholecystectomy and the risk of colon cancer.

OBJECTIVE: The relationship between cholecystectomy and the occurrence of subsequent colon cancer has been controversial. Using data collected as part of an incident case-control study of colon cancer conducted in northern California, Minnesota, and Utah, we evaluated this association. METHODS: Participants were between 30 and 79 yr of age and had a first primary colon cancer diagnosed between October 1, 1991 and September 30, 1994. Analyses were adjusted for age, gender, family history of colorectal cancer, body mass index, dietary energy and fiber intake, use of aspirin or nonsteroidal antiinflammatory drugs, and long-term leisure-time vigorous physical activity. RESULTS: A weak positive association between cholecystectomy and proximal colon cancer (odds ratio [OR] and 95% confidence interval [CI] 1.3 [1.0-1.6]) was observed. This was counterbalanced by a weak, nonsignificant negative association (OR 0.8, 95% CI 0.6-1.1) with distal colon cancer leading to no overall association (OR 1.0, 95% CI 0.9-1.2). The association between colon cancer and cholecystectomy did not differ by gender or race, but it did differ by study area, with most of the increased association being attributed to the Minnesota population. The elevated risk of proximal colon cancer increased after cholecystectomy but disappeared after 14 years. CONCLUSIONS: Our results suggest that cholecystectomy or the underlying gallstone disease that prompts it may be related weakly to the risk of subsequent proximal colon cancer. However, the association may differ by geographic area of the country, and may be artifactual at least in part.

Adult↗
PubMed1999

Methylenetetrahydrofolate reductase, diet, and risk of colon cancer.

Individuals with different forms of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, carriers of the C677T mutation versus wild type, show differences in enzyme levels; these differences have been hypothesized to be related to DNA methylation and, perhaps, to the nucleotide pool size. Using data from an incident case-control study, we evaluated the combined effect of dietary intake of folate, methionine, vitamin B6, vitamin B12, and alcohol and various forms of the MTHFR gene on risk of colon cancer. Individuals homozygous for the variant form of the MTHFR gene (TT) had a slightly lower risk of colon cancer than did individuals who were wild type [CC, odds ratio (OR) = 0.8, 95% confidence interval (CI) = 0.6-1.1 for men; and OR = 0.9, 95% CI = 0.6-1.2 for women]. High levels of intake of folate, vitamin B6, and vitamin B12 were associated with a 30-40% reduction in risk of colon cancer among those with the TT relative to those with low levels of intake who were CC genotype. Associations were stronger for proximal tumors, in which high levels of intake of these nutrients were associated with a halving of risk among those with the TT genotype. The inverse association with high levels of these nutrients in those with the TT genotype was stronger among those diagnosed at an older age. Although imprecise, the inverse association with the low-risk diet that was high in folate and methionine and without alcohol was observed for both the TT genotype (OR = 0.4 95% CI = 0.1-0.9) and the CC/CT genotype (OR = 0.6, 95% CI = 0.4-1.0), but this association was not seen with the high-risk diet for either the TT or CC/CT genotype. Although associations were generally weak, these findings suggest that those with differing MTHFR genotypes may have different susceptibilities to colon cancer, based on dietary consumption of folate, vitamin B6, and vitamin B12.

Adult↗
PubMed1999

Regional reproducibility of microsatellite instability in sporadic colorectal cancer.

The reproducibility of microsatellite instability from different regions of the same sporadic colon cancer has not been addressed. We therefore microdissected and extracted DNA from three to nine separate regions of 13 highly unstable sporadic colon cancers. Each region was then evaluated by polymerase chain reaction amplification of 17 microsatellites: 10 tetranucleotide repeats, 2 noncoding mononucleotide repeats (BAT-26 and BAT-40), and 5 coding mononucleotide repeats (TGFBRII, BAX, MSH3, MSH6, IGFIIR). Microsatellite instability showed 100% regional reproducibility with respect to either the panel of 10 tetranucleotide repeats or BAT-26, and nearly 100% reproducibility with BAT-40, although regional variation in the percent instability and the size of unstable alleles was present. TGFBRII was more frequently mutated than any other coding mononucleotide repeat; frame shifts in this gene were identified in nearly every region of every tumor. Each of the five coding repeats showed regional variability in at least one tumor, and 10 of the 13 tumors showed variability with at least one coding repeat. This variability took the form of different mutant alleles (TGFBRII, BAX, MSH3) or mutations present in some but not all regions of a tumor (MSH6, IGFIIR, BAX, MSH3). We conclude that the regional reproducibility of generalized microsatellite instability as measured by noncoding repeats indicates that sampling is not a problem in these highly unstable tumors, and that the mismatch repair deficiency phenotype is acquired in the very late adenoma stage or early cancer stage of sporadic colonic tumorigenesis. The high frequency of TGFBRII mutations is consistent with acquisition of these mutations at a similar stage of tumorigenesis. The regional variability with respect to the presence or absence of a mutation in the other four coding mononucleotide repeats could lead to sampling error and is consistent with a somewhat later time of acquisition of these mutations. Genes Chromosomes Cancer 26:106-114, 1999.

Adult↗
PubMed1999

Meat consumption, genetic susceptibility, and colon cancer risk: a United States multicenter case-control study.

Meat consumption may especially increase risk of colon cancer when the meat is prepared at high temperatures and consumed by subjects with an inherited susceptibility to well-done meat. In this United States case-control study, the association between meat consumption, genetic susceptibility, and colon cancer risk was studied. Meat consumption data were available from a detailed diet history questionnaire and from questions about methods of preparation. Molecular variants in the carcinogen-metabolizing genes NAT2 and GSTM1 were determined in DNA extracted from WBCs. A total of 1542 cases and 1860 population-based controls were included in these analyses. The amount of red and white meat consumed was not associated with overall colon cancer risk. Processed meat consumption was weakly positively associated with colon cancer risk in men only (odds ratio for highest versus lowest quintile of intake = 1.4, 95% confidence interval = 1.0-1.9). The frequency of fried, broiled, baked, or barbecued meat, use of drippings, and doneness of meat were not significantly associated with risk. The Mutagen Index, as an estimate for exposure to mutagenic or carcinogenic substances, was slightly positively associated with colon cancer risk in men (odds ratio = 1.3, 95% confidence interval = 1.0-1.7). No significant associations with colon cancer risk were observed for different NAT2 and GSTM1 gene variants. The observed associations with processed meat and the Mutagen Index were strongest for those with the intermediate or rapid NAT2 acetylator phenotype. Associations were not markedly influenced by lack of the GSTM1 gene. This study provides little support for an association between meat consumption and colon cancer risk but does provide some, albeit not strong, evidence for a modifying effect of molecular variants of the NAT2 gene.

Adult↗
PubMed1998

Comparison of the Block and the Willett self-administered semiquantitative food frequency questionnaires with an interviewer-administered dietary history.

The performances of two commonly used diet instruments, the Block and the Willett food frequency questionnaires, were compared with a longer, interviewer-administered diet history. Participants in a case-control study on diet and colon cancer were interviewed between 1990 and 1994 in northern California, Utah, and Minnesota by trained nutritionists using a validated diet history. Two separate subsamples of participants were asked to complete either the Block or the Willett questionnaire exactly 5 days after they completed the original diet history. Data were analyzed separately by subsample comparing either the Block or the Willett questionnaire with the original diet history by using means, correlations, quintile agreement, and odds ratios for the relation between several nutrients and colon cancer. The Block and the Willett questionnaires generally provided lower absolute intake estimates than did the original diet history; however, the Block questionnaire underestimated more than did that by Willett. Both correlations and quintile agreement were slightly better for the Willett questionnaire than for that by Block when compared with the original diet history. In general, point estimates obtained from either the Block or the Willett questionnaire fell within the confidence intervals of the estimates of the odds ratios obtained from the original diet history, and no real difference in significance levels appeared. Although the Block and Willett questionnaires differed slightly from each other and from our original diet history in estimating absolute nutrients and ranking or classifying individuals, they were very similar in their ability to predict disease outcome.

Adult↗
PubMed1998

Risk of colon cancer associated with a family history of cancer or colorectal polyps: the diet, activity, and reproduction in colon cancer study.

The Diet, Activity, and Reproduction in Colon Cancer (DARCC) study is a large, multi-center case-control study of colon cancer. We examined family histories of cancer among first-degree relatives obtained by computer-assisted in-person interviews from the DARCC to study the impact of family histories of several cancers and colorectal polyps on colon cancer risk. We examined familial cancer risks both by treating a family history of polyps or cancer as a covariate in a logistic regression model, and by comparing cancer or polyp incidence among relatives of cases to incidence among relatives of controls in a proportional hazards model. There were few differences between the odds ratios (OR) or confidence intervals (CI) generated from logistic regression models and the hazard rate ratios (HRR) generated from the proportional hazards models. Overall, the OR of colon cancer among subjects with a family history of colorectal cancer was 1.77. There were only minor differences in risk by sex, age and subsite. A family history of colorectal polyps also increased risk by about the same amount as a family history of colorectal cancer. The increased risk associated with a family history of polyps did not appear to decrease with age.

Adult↗
PubMed1998

Physical activity and breast cancer: evaluation of physical activity assessment methods.

Studies of the association between physical activity and breast cancer have yielded inconsistent findings. These findings may be related to a true null association or an inability to measure physical activity with enough precision to measure a protective relation. The authors reviewed and critiqued physical activity measurement methods used in published studies of the association between physical activity and breast cancer. The authors examined the quality of physical activity measures in 20 published studies. A summary score was created to rank the quality of the activity score. Studies with higher scores had a more precise measure of physical activity. Physical activity measurement methods were different in each study. Activity was measured by job classification, occupational tasks, participation in competitive athletics, and recreational and leisure-time pursuits. The recall period for physical activity ranged from a lifetime to the past year. Comparison of quality scores showed no associations between the precision of activity measures and the study results. Future studies of physical activity and breast cancer should utilize standardized methods to measure physical activity. Researchers should be encouraged to choose a measure based on hypotheses regarding physical activity and breast cancer mechanisms. Studies also should extend to subgroups of women with differences in other breast cancer risk factors, such as body mass, menopausal status, and hormone replacement status.

Breast Neoplasms↗
PubMed1998

Eating patterns and risk of colon cancer.

Colon cancer has been associated with several nutrients and foods. The authors used data from a population-based study conducted in Northern California, Utah, and Minnesota to examine associations between dietary eating patterns and risk of developing colon cancer. Through factor analysis, detailed dietary intake data obtained from 1,993 cases (diagnosed in 1991-1994) and 2,410 controls were grouped into factors that were evaluated for relations with lifestyle characteristics and colon cancer risk. Several dietary patterns emerged. The dietary patterns with the most variation were labeled "Western," "prudent," "high fat/sugar dairy," "substituters," and "drinkers." The "Western" dietary pattern was associated with a higher body mass index and a greater intake of total energy and dietary cholesterol. The "prudent" pattern was associated with higher levels of vigorous leisure time physical activity, smaller body size, and higher intakes of dietary fiber and folate. Persons who had high scores on the "drinker" pattern were also more likely to smoke cigarettes. The "Western" dietary pattern was associated with an increased risk of colon cancer in both men and women. The association was strongest among people diagnosed prior to age 67 years (for men, odds ratio (OR)=1.96, 95% confidence interval (CI) 1.22-3.15; for women, OR=2.02, 95% CI 1.21-3.36) and among men with distal tumors (OR=2.25, 95% CI 1.47-3.46). The "prudent" diet was protective, with the strongest associations being observed among people diagnosed prior to age 67 years (men: OR=0.63, 95% CI 0.43-0.92; women: OR=0.58, 95% CI 0.38-0.87); associations with this dietary pattern were also strong among persons with proximal tumors (men: OR=0.55, 95% CI 0.38-0.80; women: OR=0.64, 95% CI 0.45-0.92). Although "substituters" (people who substituted low fat dairy products for high fat dairy products, margarine for butter, poultry for red meat, and whole grains for refined grains) were at reduced risk of colon cancer, the reduction in risk was not statistically significant. These data support the hypothesis that overall dietary intake pattern is associated with colon cancer, and that the dietary pattern associated with the greatest increase in risk is the one which typifies a Western-style diet.

Adult↗
PubMed1998

Drugs and colon cancer.

In a case-control study of colon cancer conducted in three geographic regions of the United States, 1993 case subjects and 2410 control subjects were interviewed. In addition to queries regarding other known or suspected risk factors, subjects were asked about their use of eight drugs or drug groups. Two of these, aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), have been inversely associated with risk in other studies. Three others--asthma medications, digitalis preparations, and phenmetrazine--were positively associated and the last three--diazepam, penicillin, and phenformin--were negatively associated with risk of colon cancer in an earlier study that screened pharmaceuticals for possible carcinogenic effects. Reported use of aspirin and NSAIDs were both inversely related to risk with essentially the same odds ratios (0.7, 95% confidence interval 0.6-0.8) for both drugs in both univariate and multivariate analyses controlling for use of each other and for other colon cancer risk factors. Subdivision by age at starting the drug, duration of use, latency interval, sex, race, family history of colon cancer, or proximal versus distal cancer revealed no substantial differences among subgroups for either aspirin or NSAIDs, but reduced risk was associated primarily with recent aspirin use. Phenformin showed a strong positive association but the data concerning this drug appeared to be inaccurate. The other drugs and drug groups showed essentially no association with colon cancer risk.

Journal Article↗
PubMed1998

Statistical methods in epidemiology: a comparison of statistical methods to analyze dose-response and trend analysis in epidemiologic studies.

Evaluation of various statistical methods to describe accurately associations between exposures and disease are constantly being explored. Spline regression has been suggested as an alternative to using categorized variables in studies of disease etiology, as it uses all data points to estimate the shape of the association between a given exposure and disease outcome. It has been proposed that this method is especially beneficial when associations are concentrated in a small range of the overall distribution of the exposure. In this study, we use data from a large case-control study of colon cancer to evaluate associations obtained from logistic regression models that use spline regression for main exposure and confounder effects with those that use categorized variables for main exposure. Our results show that for variables for which the association appears to be linear, such as body size and dietary intake of calcium, fiber, and cholesterol, associations are similar when estimates are generated from spline or categorized variable models. For other variables, such as total energy intake, for which associations appear to be strongest in the upper end of the distribution, estimates of association appear to be conservative when using categorized variables. The data also suggest that selection of cut points for the categorized variables may have an impact on the associations observed. Spline regression appears to be useful to estimate the shape of the association between a given exposure and disease and may provide guidance as to the appropriateness of using categorized variables. The risk estimates from spline regression appear to be similar to those from traditional categorical methods. When effects are large or rapidly changing, spline models may more appropriately describe the association.

Adult↗
PubMed1998

Measurement errors stemming from nonrespondents present at in-person interviews.

PURPOSE: Data are frequently collected from in-person interviews in epidemiologic studies. Despite the advantages of this mode of data collection, the presence of a third party during the interview can contribute to measurement error, especially if third-party presence is related to case status. METHODS: Using data obtained from a case-control study of colon cancer, we evaluated the frequency of third-party presence during in-person interviews, and how having someone else present during the interview influences reporting of exposure data. RESULTS: Interviews were conducted in the presence of a third party for 28% of cases and 22% of controls who lived in a household of two or more individuals. Men with a third party present reported significantly lower age-adjusted mean levels of alcohol consumption (P < 0.01). Associations, as indicated by odds ratios, between colon cancer and alcohol intake were not statistically different among those with a third party present and those without a third party present. Although not statistically significant, energy intake was more strongly associated with colon cancer among those without a third party present during the interview. CONCLUSIONS: These results emphasize the need to review questions to be asked and decide whether privacy should be emphasized before data collection begins. If privacy is required, interviewers need to be given better skills to ensure privacy during interview.

Adult↗
PubMed1998

Body size and the risk of colon cancer in a large case-control study.

OBJECTIVE: To investigate the risks of height, weight and body fat distribution associated with colon cancer in subcategories of gender, age and site in the colon. Interaction with family history of colorectal cancer is also examined. DESIGN: Case-control study of diet, anthropometry and colon cancer risk. SUBJECTS: Nineteen hundred and eighty-three colon cancer cases (age 30-79 y) and 2400 age and gender matched population controls. MEASUREMENTS: Height, weight and waist and hip circumferences were obtained by trained interviewers. Body Mass Index (BMI) and Waist-Hip Ratio (WHR) were calculated. RESULTS: Of all anthropometric measurements examined, only BMI was consistently associated with an increased risk of colon cancer. The test for trend for BMI was significant for men and women overall and for the majority of subgroups examined. In younger persons those with a family history of colorectal cancer had a greater risk of colon cancer associated with BMI (Men odds ratio (OR) = 7.76, 95% confidence interval (CI) 2.60, 23.1; Women OR = 4.85, 95% CI 2.33, 10.12) comparing the third tertile to the first, than those with no family history (Men OR = 1.70, 95% CI 1.25, 2.32; Women OR = 1.53, 95% CI 1.22, 1.92). WHR, after controlling for BMI was not associated with colon cancer in men, and was associated with a slight increase in women (primarily in those with distal tumors). CONCLUSION: This study contributes to mounting evidence that excess weight is associated with an increased risk of colon cancer.

Adult↗
PubMed1998

Vitamin E and colon cancer: is there an association?

The role of vitamin E in the etiology and prevention of colon cancer is not clear. It is possible that various forms of vitamin E may act differently in colon tissue and may be effective chemopreventive agents. Previous reports of vitamin E and colon cancer have focused on alpha-tocopherol and have not considered other dietary forms of vitamin E. Data from a study of 1,993 cases and 2,410 controls were used to evaluate the associations between the four most common forms of dietary vitamin E and supplemental vitamin E and colon cancer. After adjusting for other health and life-style factors, we did not observe a statistically significant association between dietary tocopherols and colon cancer. There were, however, suggestions of an inverse association between total alpha-tocopherol equivalents and colon cancer among women diagnosed with colon cancer before the median age of the control population, 67 years [odds ratio (OR) = 0.66, 95% confidence interval (CI) = 0.36-1.22] and a direct association between gamma-tocopherol and colon cancer among these women (OR = 1.44, 95% CI = 0.92-1.93). Women diagnosed with colon cancer when > or = 67 years of age appeared to have some protection from use of vitamin E supplements (OR = 0.80, 95% CI = 0.56-1.15). These data offer only limited support for a protective effect of vitamin E and colon cancer after adjustment for other health and life-style factors.

Adult↗
PubMed1998

Stage of colon cancer at diagnosis: implications for risk factor associations?

BACKGROUND: A potential source of bias in epidemiological studies comes from studying people at different stages of disease progression. This can result in biased selection of cases or in errors of measurement of exposures. METHODS: We use stage of disease at the time of diagnosis to evaluate how inclusion of people at different stages in the disease process can influence associations between environmental exposures and colon cancer. Data used were generated from a large case-control study of colon cancer. RESULTS: For most environmental exposures evaluated, including physical activity, body size, use of aspirin and of non-steroidal anti-inflammatory drugs, and dietary intake of folate and fibre, we did not observe differences in patterns of association by stage of disease at diagnosis. However, for total energy and red meat intake (men only), alcohol consumption, cigarette smoking, and family history of colorectal cancer among first degree relatives, patterns of associations were stronger when colon cancer was detected at an earlier stage of disease progression than when it was detected at a more advanced stage. CONCLUSIONS: Most exposures did not differ by stage of disease, thus selectively excluding cases at different disease stages should not influence associations between these exposures and colon cancer. Associations for other factors, such as alcohol consumption and cigarette smoking, may be biased from asking cases with advanced disease to recall a non-disease-free time period. Associations with family history may also be biased if those with a family history of colorectal cancer are detected at an earlier stage and therefore more likely to participate in epidemiological studies.

Adult↗