Biomedical subjects

M L Slattery

Publications and source records attributed to M L Slattery.

At least 19 recordsLinked to original sources

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↗

PubMed1997

Dietary fats and colon cancer: assessment of risk associated with specific fatty acids.

There are many biological mechanisms whereby dietary fat and specific dietary fatty acids may alter risk of colon cancer in addition to their contribution to total energy intake. To evaluate these potential associations, we used detailed dietary intake data collected in a population-based study of 1,993 incident colon cancer cases and 2,410 controls conducted in 3 areas of the United States. The most commonly consumed fatty acid in the study population was oleic acid. One-third of dietary fats consumed came from additions to other foods at the table or from the preparation of other foods. After adjusting for total energy intake, physical activity and body size, neither total dietary fat nor specific fatty acids was associated with risk of colon cancer. However, among older women, fats from food preparation were associated with increased risk of colon cancer (OR 1.84, 95% CI 1.20-2.80), while fats from foods themselves or from additions to other foods were not. While dietary fats were not associated with colon cancer risk in the total population, subgroups of the population appeared to be at slightly greater risk if they consumed a high-fat diet. Women who consumed a diet high in mono-unsaturated fatty acids (MFAs) and poly-unsaturated fatty acids (PFAs) and who had a family history of colorectal cancer were at greater risk of colon cancer than those with similar intakes but without a family history of colorectal cancer. Similar associations with family history were noted among men diagnosed at younger ages for MFA, linolenic acid and 20-carbon PFA.

Adult↗

PubMed1997

Comparison of self-reported and database-linked family history of cancer data in a case-control study.

The authors linked interview data drawn from Utah participants in the Diet, Activity, and Reproduction in Colon Cancer (DARCC) Study (1992-1995) to genealogic and cancer information contained in the Utah Population Database (UPDB). They evaluated the sensitivity of subjects' reports of familial cancers and measured the overall agreement between reported and database records with the kappa (kappa) statistic. They calculated odds ratios from logistic regression to compare the relative risk estimates that would result from use of either data set (or both data sets). Overall, 37.6% (331 of 881) of the Utah DARCC subjects were linked to the UPDB genealogy. High sensitivities were observed for subjects' reports of breast (83%), colorectal (73%), and prostate (70%) cancers, while ovarian (60%) and uterine (30%) cancers were not reported as well. Results for kappa were similar, with values of 0.63 for breast cancer and 0.56 for colorectal cancer. Although the observed kappa s of 0.36 and 0.25 for ovarian and uterine cancers, respectively, exceeded chance expectations, the agreement between subjects' reports and database records was unimpressive. No consistent difference was observed between cases and controls in the accuracy of self-reports. In general, higher sensitivities were observed among younger subjects than older subjects; females reported family histories of cancer only slightly better than males. A college education was not consistently associated with more accurate reporting of family history of cancer. These results indicate that subjects in a case-control study are able to report accurately family histories of several common kinds of cancer and that they can do so without observable recall bias. The accuracy of self-reports may not be adequate for reproductive tract cancers and cancers such as rectal cancer that are frequently confused with cancers of similar organs.

Adult↗

PubMed1997

Dietary energy sources and colon cancer risk.

Because energy-contributing nutrients are highly correlated with total energy, the association with colon cancer from energy versus other components of energy-providing nutrients is often not clear. Dietary data from a population-based case-control study of colon cancer were analyzed in subjects from California, Utah, and Minnesota in 1991-1994 to assess the colon cancer risk associated with consumption of energy, fat, protein, and carbohydrate. After adjustment for long-term physical activity, total energy intake increased risk of colon cancer in men (odds ratio = 1.74, 95% confidence interval 1.14-2.67 for highest vs. lowest quartile) and in women (odds ratio = 1.70, 95% confidence interval 1.07-2.70). Various methods of analysis suggested that intakes of individual sources of energy (dietary fat, protein, and carbohydrate) were not associated with colon cancer risk after total energy intake was taken into account. People who consumed a high-calorie diet that was dense in fiber and calcium appeared to be at lower risk than people with the same caloric intake who consumed smaller amounts of dietary fiber and calcium. Individuals with a first-degree relative with colorectal cancer, especially those diagnosed at a younger age, were at a greater risk from a diet high in energy than were individuals without a family history of colorectal cancer.

Adult↗

PubMed1997

Tobacco use and colon cancer.

Smoking cigarettes has been consistently associated with adenomatous polyps. However, only a few studies have reported associations between smoking cigarettes or using other forms of tobacco and colon cancer. A population-based case-control study of colon cancer was conducted in 3 areas in the United States: northern California, Utah and Minnesota. We observed approximately a 50% increase in colon cancer risk from smoking over a pack of cigarettes per day among both men and women. Those who stopped smoking remained at increased risk, even if they stopped over 10 years ago. Our data suggest that the amount smoked may be a more important factor than the total number of years smoked. Smoking neither cigars nor pipes was associated with an increased risk of colon cancer. Among female participants only, those who smoked over 20 cigarettes per day and had a large body mass index were at greater risk of colon cancer than participants who smoked the same amount but were smaller (p for interaction among women = 0.04).

Adolescent↗

PubMed1997

Energy balance and colon cancer--beyond physical activity.

Low levels of physical activity and high levels of energy intake and body mass have all been directly associated with colon cancer. The purpose of this study was to determine how physical inactivity interacts with other components of energy balance (energy intake and body mass) in determining colon cancer risk. Data were obtained from 2073 first primary cases of colon cancer and 2466 age- and sex-matched controls identified from 8 counties in Utah, the Northern California Kaiser Permanente Medical Care Program, and the Twin Cities metropolitan area in Minnesota. Recent and lifetime physical activity was assessed by intensity of activities performed at home, leisure, and at work; energy intake was estimated from an extensive diet history questionnaire; and body mass index (BMI) was calculated from measured height at the time of interview and reported weight for the referent year. For both men and women, lack of lifetime vigorous leisure-time activity was associated with increased risk of colon cancer [odds ratio (OR), 1.63 and 95% confidence interval (CI), 1.26-2.12 for men and OR, 1.59 and 95% CI, 1.21-2.10 for women, comparing the lowest to highest level of activity]. There were no differences in risk associated with physical activity by tumor site within the colon or by age at diagnosis. High levels of energy intake were also associated with increased risk of colon cancer in men and women (OR, 1.74 and 95% CI, 1.14-2.67 for men and OR, 1.70 and 95% CI, 1.07-2.70 for women). A large BMI was more associated with increased risk in men (OR, 1.94 and 95% CI, 1.49-2.54) than in women (OR, 1.45 and 95% CI, 1.08-1.94). Those at greatest risk of colon cancer were those who had the most unfavorable energy balance in that they were physically inactive, had high energy intakes, and had a large BMI (OR, 3.35 and 95% CI, 2.09-5.35). However, when physical activity was high, having a high energy intake and large BMI resulted in a nonsignificant increased colon cancer risk (OR, 1.28 and 95% CI, 0.81-2.03). This pattern was consistent between the sexes, but there was some evidence that men may be at higher risk than women, especially older women, as a result of unfavorable energy balance. These results support previous findings that physical inactivity, high energy intake, and large body mass are associated with increased risk of developing colon cancer. However, energy balance as a whole seems to be associated with risk of colon cancer. These findings suggest systemic metabolic influences on carcinogenesis and have important implications for prevention.

Adult↗

PubMed1997

Microsatellite instability in colorectal adenomas.

BACKGROUND & AIMS: Microsatellite instability in apparently sporadic, predominantly right-sided colon cancers seems to be the result of an acquired, rather than germline, genetic change that impairs mismatch repair. The timing of this change with respect to the adenomacarcinoma sequence has not been determined. The aim of this study was to evaluate colonic adenomatous polyps for microsatellite instability to determine whether instability reflects an early genetic change in colonic neoplasia. METHODS: Ninety-three sporadic colonic adenomas (44 right-sided and 49 left-sided) from 48 individuals were evaluated for microsatellite instability with a set of 10 polymerase chain reaction primer sets. RESULTS: Eighty percent of adenomatous polyps showed no instability. Ninety-eight percent showed instability with <30% of primer sets. Aside from one right-sided adenoma with 78% instability, there was no level of instability with a higher proportion of right-sided than left-sided adenomas. CONCLUSIONS: Colonic adenomas show far less microsatellite instability than carcinomas, and the marked right-sided predominance of instability observed in colon cancers was not observed. Instability is usually not an early event in the development of colonic neoplasia. A distinct pathway to sporadic colorectal cancer initiated by mismatch repair deficiency, although not excluded, is not suggested by these data.

Adenoma↗

PubMed1997

Physical activity and colon cancer: a public health perspective.

PURPOSE: It has been suggested that performing physical activity for at least 30 min on most days of the week will improve health. The purpose of this study was to assess the association between physical activity and colon cancer as it relates to this public health recommendation. METHODS: A large population-based case-control study of colon cancer was conducted. Study participants came from three areas of the United States: Northern California, Utah, and the Twin Cities Metropolitan Area in Minnesota. RESULTS: Long-term involvement in high levels of activity, equivalent to > or = 60 min of vigorous activity per session, was associated with decreased risk (odds ration [OR], 0.68; 95% confidence interval [CI] 0.52-0.87). The amount of time involved in the activity appeared to have a greater impact than the number of days per week that activities were performed. Those reporting the highest level of activity, as defined by both duration and vigorous intensity, were at the lowest risk (OR, 0.62; 95% CI, 0.52-0.75) relative to those who were sedentary; associations did not differ by age at diagnosis, site of the tumor within the colon, or sex. The inverse association between colon cancer and long-term vigorous leisure-time activity was slightly stronger among those without a family history of colorectal cancer than among those with a family history of colorectal cancer. From these data we estimate that 13% of colon cancer could be attributed to lack of vigorous leisure-time activity in the population; we estimate that 4.3 cases of colon cancer/100,000 population are prevented each year because people are involved in vigorous leisure-time physical activity. CONCLUSIONS: Data from this study suggest that a high level of vigorous leisure-time activity performed over the past 20 years was important in reducing colon cancer risk; the greatest inverse association was observed when activities were performed for longer periods of time per session for the past 20 years. These and other data indicate that it is important to identify ways to facilitate an increase in leisure-time physical activity within the population.

Adult↗

PubMed1997

Performance of a shortened telephone-administered version of a quantitative food frequency questionnaire.

PURPOSE: We evaluated the performance of a telephone-administered food frequency questionnaire in a study of 190 men and women, 30-79 years of age, who participated as controls in a study of colon cancer. METHODS: The telephone version of the questionnaire was modified from a longer food frequency questionnaire originally administered in person to each of the participants. One month later, the telephone questionnaire was administered to a subgroup of 190 participants and readministered to 169 members of the subgroup two weeks later to assess the reproducibility and comparative validity of the instrument. RESULTS: The unadjusted correlation for energy between the original in-person full food frequency questionnaire and the abbreviated telephone version was 0.69. The median energy intake from the telephone version was 17% lower in men and 23% lower in women. The energy and sex-adjusted correlation coefficients for other nutrients ranged from 0.45 for vitamin E to 0.78 for fiber. The intraclass correlation coefficients to measure reproducibility ranged from 0.62 for animal protein to 0.83 for folate. CONCLUSIONS: These data indicate that this brief, telephone-administered questionnaire is reproducible and provides a ranking of nutrient intake comparable to that provided by a full in-person interview.

Adult↗

PubMed1997

Diet diversity, diet composition, and risk of colon cancer (United States).

In this study, we evaluate diet diversity, diet composition, and risk of colon cancer in an incident population-based study of 1,993 cases and 2,410 controls in the Kaiser Permanente Medical Care Program of Northern California, eight counties in Utah, and the Twin Cities area of Minnesota (United States). Ninety-one and one-half percent of the population were non-Hispanic White. Dietary intake was obtained using an adaptation of the CARDIA diet-history questionnaire. Diet diversity was defined as the number of unique food items reported; diversity also was explored within six major food groups. Composition of the diet was described by estimating the proportion of total number of food items contributed by major food groups. Younger individuals, higher educated individuals, and those who lived in larger households reported eating the most diverse diet. Total diet diversity was not associated with colon cancer. However, eating a diet with greater diversity of meats, poultry, fish, and eggs, was associated with a 50 percent increase in risk among all men (95 percent confidence interval [CI] = 1.1-2.0; P trend = 0.01), with slightly stronger associations for younger men and men with distal tumors. A diet with a greater number of refined grain products also was associated with increased risk among men (odds ratio [OR] = 1.7, CI = 1.3-2.3). Women who ate a diet with a more diverse pattern of vegetables were at approximately a 20 percent lower risk than women who had the least diverse diet in vegetables. Assessment of diet composition showed that men who consumed a large proportion of their food items from meat, fish, poultry, and eggs were at an increased risk, with the most marked association being for distal tumors (OR = 1.7, CI = 1.2-2.5). Women who consumed the largest percentage of their food items in the form of plant foods (fruits, vegetables, or whole grains) were at a reduced risk of developing colon cancer (OR = 0.7, CI = 0.5-1.0).

Adult↗

PubMed1997

Hormone replacement therapy, reproductive history, and colon cancer: a multicenter, case-control study in the United States.

Hormonal factors have been inconsistently associated with colon cancer risk in women. The associations between reproductive events, menstrual factors, exogenous hormones, and colon cancer were evaluated in a large case-control study (894 female cases and 1,120 female age-matched population-based controls) in the United States, stratifying by age at diagnosis, tumor site, family history and other potential risk factors. Overall, higher parity was associated with a marginally decreased risk of colon cancer (five or more births compared with nulliparous: odds ratio [OR] = 0.75, 95 percent confidence interval [CI] = 0.53-1.06) after adjusting for age at diagnosis, family history of colorectal cancer, vigorous lifetime physical activity, body mass index (BMI) (wt/ht1.5), total energy intake, and aspirin use. No important associations were observed for other reproductive or menstrual events. An inverse association between recent use of hormone replacement therapy (HRT) and colon cancer was observed (OR = 0.71, CI = 0.56-0.89). Although interaction terms were not significant, this inverse association appeared to be more pronounced for those with an older age at diagnosis; for those without a first-degree relative with colorectal cancer; and for those with a relatively low BMI. The reduced risk associated with HRT use did not appear to be explained by other behaviors related to HRT use.

Adult↗

PubMed1997

The relationship between dietary fat intake and risk of colorectal cancer: evidence from the combined analysis of 13 case-control studies.

The objective of this study was to examine the effects of the intake of dietary fat upon colorectal cancer risk in a combined analysis of data from 13 case-control studies previously conducted in populations with differing colorectal cancer rates and dietary practices. Original data records for 5,287 cases of colorectal cancer and 10,470 controls were combined. Logistic regression analysis was used to estimate odds ratios (OR) for intakes of total energy, total fat and its components, and cholesterol. Positive associations with energy intake were observed for 11 of the 13 studies. However, there was little, if any, evidence of any energy-independent effect of either total fat with ORs of 1.00, 0.95, 1.01, 1.02, and 0.92 for quintiles of residuals of total fat intake (P trend = 0.67) or for saturated fat with ORs of 1.00, 1.08, 1.06, 1.21, and 1.06 (P trend = 0.39). The analysis suggests that, among these case-control studies, there is no energy-independent association between dietary fat intake and risk of colorectal cancer. It also suggests that simple substitution of fat by other sources of calories is unlikely to reduce meaningfully the risk of colorectal cancer.

Adult↗

PubMed1997

Plant foods and colon cancer: an assessment of specific foods and their related nutrients (United States).

Plant foods have been associated inversely with colon cancer. Since a major focus of this study was to identify components of plant foods which may account for their association with colon cancer, nutrients which are commonly found in plant foods also were evaluated. A population-based case-control study was conducted in Northern California, Utah, and the 'Twin Cities' area of Minnesota (United States). Complete data were available from interviewer-administered questionnaires on 1,993 cases and 2,410 controls. Higher intakes of vegetables (for highest relative to lowest quintile of intake) were associated inversely with colon cancer risk: the odds ratio (OR) was 0.7 for both men (95 percent [CI] confidence interval = 0.5-0.9) and women (CI = 0.5-1.0). Associations were stronger among those with proximal tumors. Total fruit intake was not associated with colon cancer risk although, among men, higher levels of whole grain intake were associated with a decreased risk (OR = 0.6, CI = 0.4-0.9 for older men); high intakes of refined grains were associated with an increased risk (OR = 1.5, CI = 1.1-2.1). Dietary fiber intake was associated with a decreased risk of colon cancer: OR = 0.5 (CI = 0.3-0.9) for older men; OR = 0.7 (CI = 0.4-1.2) for older women; OR = 0.6 (CI = 0.4-1.0) for men with proximal tumors; OR = 0.5 (CI = 0.3-0.9) for women with proximal tumors. Other nutrients, for which plant foods were the major contributor--such as vitamin B6, thiamin, and niacin (women only)--also were associated inversely with colon cancer. Neither beta-carotene nor vitamin C was protective for colon cancer. Adjustment of plant foods for nutrients found in plant foods or for supplement use did not appreciably alter the observed associations between plant foods and colon cancer.

Adult↗

PubMed1997

Are dietary factors involved in DNA methylation associated with colon cancer?

Disturbances in DNA methylation have been hypothesized as being involved in carcinogenesis. It has been proposed that dietary factors such as folate, alcohol, and methionine may be associated with colon cancer because of their involvement in DNA methylation processes. Data from a large retrospective population-based case-control study of incident colon cancer were used to evaluate whether intake of alcohol and other dietary factors involved in DNA methylation are associated with colon cancer. Dietary data were obtained using a detailed diet history questionnaire. We did not observe strong independent associations between folate, vitamin B6, vitamin B12, methionine, or alcohol and risk of colon cancer after adjusting for body size, physical activity, cigarette smoking patterns, energy intake, and dietary intake of fiber and calcium. However, when assessing the associations between colon cancer and a composite dietary profile based on alcohol intake, methionine, folate, vitamin B12, and vitamin B6, we observed a trend of increasing risk as one moved from a low- to a high-risk group. This trend was modest and most marked in those diagnosed at a younger age [odds ratio (OR) for men = 1.3, 95% confidence interval (CI) = 0.9-1.9; OR for women = 1.6, 95% CI = 1.0-2.6]. We observed that associations with this high-risk dietary profile were greater among those who took aspirin or nonsteroidal anti-inflammatory drugs on a regular basis and were younger at the time of diagnosis (men OR = 1.7, 95% CI = 1.0-3.2; women OR = 2.2, 95% CI = 1.0-4.8) and for distal tumors (men OR = 1.4, 95% CI = 0.9-2.3; women OR = 2.0, 95% CI = 1.0-3.8). Findings from this study provide only limited support for previously reported associations between dietary factors involved in DNA methylation and risk of colon cancer.

Aged↗

PubMed1997

Transforming growth factor-beta receptor type 2 mutations and microsatellite instability in sporadic colorectal adenomas and carcinomas.

Frame-shift mutations in a run of 10 adenines (A10) of the transforming growth factor-beta receptor type 2 gene (TGF-beta RII) are commonly seen in inherited and sporadic colonic cancers that exhibit microsatellite instability. A10 mutations and instability also are commonly seen in hereditary nonpolyposis colon cancer-associated adenomas. However, instability is quite rare in sporadic adenomas, and the timing of acquisition of A10 mutations with respect to the sporadic adenoma-carcinoma sequence has not been reported. We evaluated 100 sporadic colorectal cancers and 164 sporadic adenomas for microsatellite instability with a set of 10 tetranucleotide polymerase chain reaction primer sets and for A10 frame-shift mutations. A10 mutations were significantly associated with microsatellite instability in colorectal cancers, being seen in 9 of 11 cancers with 50% or greater instability and in 0 of 89 tumors with less than 50% instability (P < 0.0001). A10 mutations were not detected in any adenomas, only three of which (1.8%) exhibited significant (30% or greater) instability. We conclude that both TGF-beta RII frame-shift mutations and microsatellite instability occur at a relatively late stage of sporadic colorectal tumorigenesis. A10 frame-shift mutations appear to be restricted to sporadic colorectal cancers with extensive microsatellite instability.

Adenoma↗

PubMed1997

Dietary sugar and colon cancer.

It has been hypothesized that levels of triglycerides, glucose, and insulin are associated with risk of colon cancer and that diets high in simple sugars increase risk of colon cancer because of their impact on these factors. Limited epidemiological evidence supports the association between simple carbohydrates and risk of colon cancer. Using data from a population-based case-control study (n = 1993 cases and 2410 controls), we examined the associations between dietary sugars, foods containing high level of sugars, and dietary glycemic index (GI) and colon cancer. A dietary GI was developed to estimate metabolic response to a diet that may increase plasma glucose levels. Dietary data were obtained using a validated diet history questionnaire. High levels of sucrose intake were associated with increased risk of colon cancer among younger men [odds ratio (OR) for highest quintile relative to lowest, 1.59; 95% confidence interval (CI), 1.07-2.37]. There was also a trend of increasing colon cancer risk associated with a higher sucrose:dietary ratio for proximal tumors in both men and women. Individuals with proximal tumors who consumed a diet ranked as having a high GI were at increased risk (for men, comparing highest quintile to lowest quintile: OR, 1.58; 95% CI, 1.06-2.36; P trend 0.04; for women: OR, 1.72; 95% CI, 1.11-2.67; P trend 0.04). Those at greatest risk from a high dietary GI were those who were sedentary (for men, relative to those who were most active and had a low-GI diet: OR, 3.46; 95% CI, 1.78-6.70; for women: OR, 2.00; 95% CI, 0.98-4.07). We also observed that people who had a high sucrose: dietary fiber ration and who also were sedentary and had a large body mass index were at increased risk (OR, 4.58; 95% CI, 2.33-8.98) relative to those who had a low sucrose:dietary fiber ratio, were active, and had low body mass indices. These findings support previous reports that dietary sugars, especially diet high in simple carbohydrates relative to complex carbohydrates, increase risk of colon cancer, possibly through their impact on plasma glucose levels.

Adult↗

PubMed1996

A description of age, sex, and site distributions of colon carcinoma in three geographic areas.

BACKGROUND: Site of the carcinoma within the colon in relation to age and sex may provide clues into the etiology of the disease. Incidence of colon carcinoma by age, sex, and tumor site at a population-based level are reported infrequently. The goal of this study was to describe the distribution of colon carcinoma (excluding cancers of the rectosigmoid junction and rectum) by age at diagnosis, sex, and site of the tumor within the colon. These factors were also evaluated in conjunction with disease stage at the time of diagnosis. METHODS: Data from three geographically distinct populations were used to describe rates of colon carcinoma and the distribution of tumors by age, tumor site, and stage at diagnosis. All colon carcinoma cases diagnosed within a 3-year period within the areas are included. RESULTS: Approximately 50% of all cancers in men and greater than 50% of cancers in women were in the proximal segment of the colon. Men who were diagnosed prior to age 50 and both men and women diagnosed at age 70 or older had predominantly proximal cancers. People with proximal cancers and people diagnosed prior to age 50 were more likely to have more advanced disease. CONCLUSIONS: Both men and women have more proximal cancers with advancing age, which are associated with more advanced disease. Observed trends in cancer site distributions could reflect screening practices, environmental and genetic factors, or a combination of these variables.

Adult↗