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T Byers

Publications and source records attributed to T Byers.

At least 37 records · Page 2Linked to original sources
PubMed1999

A study of the relationship between family history of breast cancer and knowledge of breast cancer genetic testing prerequisites.

Awareness of hereditary breast cancer genetic testing, of breast cancer risk factors, and of increased level of risk based on family history are necessary before women can seek out genetic services. The aim of this paper is to describe the relationships between family history of breast cancer and awareness of genetic testing, knowledge of breast cancer risk factors, and perceived lifetime risk of breast cancer. An anonymous survey was administered by mail to a random sample of 600 women, 200 from each of three breast cancer family history groups (none, intermediate, and strong), drawn from a population-based registry of 240,000 women enrolled in a mammography screening program in the Denver Metropolitan area in Colorado. Awareness of genetic testing for breast cancer risk assessment was found to be significantly associated with family history of breast cancer, increasing from 35% in the lowest family history risk group to 67% in the group with the strongest familial risk (p = 0.002). In all family history groups, nearly 70% of respondents viewed high-fat diet and smoking as being important in relation to breast cancer risk, but alcohol was seen as being only somewhat important or not important by almost half of all respondents. Having a mother or sister with breast cancer was reported as being extremely or very important by nearly all respondents, regardless of family history. As expected, perceived lifetime risk for developing breast cancer was associated with family history (p = 0.001), but the perception of the lifetime risk for breast cancer was much higher among all of the family history groups than their true risk. In conclusion, educational interventions are needed to heighten women's awareness of genetic testing, to clarify women's knowledge of breast cancer risk factors, especially alcohol, and to reassure many women that their actual breast cancer risk is lower than they might perceive.

Breast Neoplasms↗
PubMed1999

The role of epidemiology in developing nutritional recommendations: past, present, and future.

Observations of the relations between food choices and health have been made since ancient times, but epidemiology, which can be regarded as the science of systematically studying these relations, has played a key role in official nutritional guidance only in recent years. In the past 20 y the principal goal of nutritional guidance has changed from the prevention of nutritional deficiencies to the prevention of chronic diseases. This evolving purpose of nutritional guidance has demanded that nutritional epidemiology play an increasingly important role. Although no other type of nutritional science can equal epidemiology in the relevance of either the dietary exposures or the health outcomes, substantial problems limit the ability of nutritional epidemiology to convincingly prove causal associations. The classic criteria for causation are often not met by nutritional epidemiologic studies, in large part because many dietary factors are weak and do not show linear dose-response relations with disease risk within the range of exposures common in the population. The most important problem in nutritional epidemiology in the past has been the inaccuracy of dietary assessment. In the future, an additional problem will be the proliferation of hypotheses that can be tested in multiple ways among the many subgroups of the population that can be defined by factors such as age, sex, and genotype. Future progress in our understanding of the relations between diet and health will necessitate improved methods in nutritional epidemiology and a better integration of epidemiologic methods with those used in the clinical nutritional sciences.

Diet↗
PubMed1999

The role of epidemiology in determining when evidence is sufficient to support nutrition recommendations. Summary statement.

This statement summarizes the key points of discussion among a group of nutritional epidemiologists who met in Washington, DC, for 2 d in October of 1997 to reflect on the role of nutritional epidemiology in the development of dietary recommendations for the public. Although imprecision in the measurement of diet places limits on nutritional epidemiology, no other field of nutritional science can provide direct information on relations between nutrition and health in free-living human populations. Among the nutritional sciences, therefore, epidemiology was regarded as being critically important. Nutritional epidemiology can be improved in the future by the development of more precise measures of long-term dietary exposures, both by improved methods of self-reporting of diet and by the development of more useful biomarkers of long-term nutritional status. There is a need as well to reconsider the applicability of causal criteria as applied to nutritional epidemiology, because many of the important associations between dietary behaviors and chronic diseases cannot necessarily be expected to be either strong or to manifest linear dose-response relations. In the future, scientific evidence from the rapidly growing field of nutritional epidemiology will likely play an increasingly important role in developing nutrition policy and advice for the public.

Causality↗
PubMed1999

Assessing alcohol consumption: beverage-specific versus grouped-beverage questions.

OBJECTIVE: The quantity-frequency method is commonly used to measure alcohol intake in large surveys. Because of time and space constraints, questionnaires are often shortened by combining questions on all types of alcohol into a single question. We investigated the effect of this practice using data from the Behavioral Risk Factor Surveillance System. METHOD: We examined data collected from 213,842 respondents to surveys conducted by 32 states and the District of Columbia participating in the years 1987, 1988, 1989 and 1990. The 1987 and 1988 surveys asked questions about respondents' frequency and level of intake of specific alcohol-containing beverages. The 1989 and 1990 surveys asked about the frequency and quantity of intake of alcohol-containing beverages by combining all beverages into a single group. RESULTS: Among drinkers, the mean number of drinks per month was higher for those who were asked beverage-specific questions than for those who were asked grouped-beverage questions (men: 37.0 vs 29.6; women: 17.0 vs 13.9). CONCLUSION: Caution must be used in comparing level of alcohol intake from surveys in which beverages are not grouped identically.

Adult↗
PubMed1999

Beta-carotene intake and risk of postmenopausal breast cancer.

We assessed the relation between beta-carotene consumption at various times in life and breast cancer risk by conducting a case-control study nested within a population-based cohort of women screened for breast cancer in Sweden. We conducted a telephone interview with 273 incident breast cancer cases and 371 controls about their diet at various ages throughout their lifetime. Controls were frequency matched to cases on age, month and year of mammography, and county of residence. We used unconditional logistic regression to measure the association between beta-carotene intake and breast cancer risk while adjusting for total energy intake, recency of intake, and the matching variables. Women were at lower risk with increasing levels of reported intake of beta-carotene. This pattern of association between breast cancer and beta-carotene intake was similar at various times before screening. These findings indicate that although diets high in beta-carotene may be associated with lower breast cancer risk, there does not seem to be evidence of a critical time period during which such diets are more relevant.

Breast Neoplasms↗
PubMed1998

Validity of self-reported diagnoses leading to hospitalization: a comparison of self-reports with hospital records in a prospective study of American adults.

The authors compared interview reports with hospitalization records of participants in a nationally representative survey to determine the accuracy of self-reports of ischemic heart disease, stroke, gallbladder disease, ulcers, cataract, hip fracture, colon polyps, and cancers of the colon, breast, prostate, and lung. The study cohort consisted of 10,523 participants from the First National Health and Nutrition Examination Survey in 1971-1975 who were aged 25-74 years at the baseline examination and who completed a follow-up interview in 1982-1984. Self-reports of hospitalization for breast cancer were confirmed as accurate for 100% of cases where a hospital record was available. Self-report accuracy was also high for ischemic heart disease (84%), cataract (83%), and hip fracture (81%); it was moderate for lung cancer (78%), prostate cancer (75%), gallbladder disease (74%), colon cancer (71%), and stroke (67%); but it was low for ulcers (54%) and colon polyps (32%). Some of the self-reports of ulcers (20%), hip fracture (9%), ischemic heart disease (7%), and stroke (7%) were found to reflect diagnoses of other conditions of anatomic proximity. Accuracy of self-reports improved with higher levels of education, but was not generally related to age, gender, race, alcohol use, or smoking. The results suggest that self-reports of some diseases can be taken as accurate, but self-reports of other conditions might require medical record verification in epidemiologic follow-up studies.

Adult↗
PubMed1998

Comparison of 4 questionnaires for assessment of fruit and vegetable intake.

OBJECTIVE: This study compared fruit and vegetable assessments derived from 4 self-administered questionnaires. METHODS: Among 102 adolescents, servings of fruits and vegetables assessed by 4 questionnaires were compared with estimates from 24-hour recalls. RESULTS: The prevalence of consuming 5 or more servings of fruits and vegetables a day was underestimated by the questionnaires. Questionnaires asking subjects to recall their diet over the previous year were more effective in ranking subjects (r's > or = .42) than those assessing previous-day diet (r's > or = .30). CONCLUSIONS: Brief assessments of fruit and vegetable intake are more useful for ranking subjects than for estimating prevalence of consumption of 5 or more servings per day.

Adolescent↗
PubMed1997

Breast cancer mortality in relation to self-reported use of breast self-examination. A cohort study of 450,000 women.

The benefits of breast self-examination (BSE) for reducing mortality from breast cancer are uncertain. We conducted an analysis of the relationship between self-reported practicing of BSE and mortality from breast cancer over 13 years in a cohort of over 548,000 women. The report of practicing BSE was unrelated to breast cancer mortality. There was a small beneficial effect in those women who were the thinnest, but this effect was small and not statistically significant. BSE was otherwise equally ineffective in subgroups defined by obesity level and family history of breast cancer. We conclude that BSE, as practiced by American women in 1959, did not reduce the risk of mortality from breast cancer.

Adult↗
PubMed1997

Dietary surveillance for states and communities.

Information about dietary behaviors, attitudes, and knowledge is important for state and local health agencies because national monitoring lacks the local representativeness and timeliness necessary to catalyze community interest and to design, target, and evaluate dietary intervention programs. Currently, however, both methods and resources are limited for surveying diet in the population of a state or community. Brief assessments are included in the Youth Risk Behavior Surveillance System for adolescents, which is conducted by state departments of education, and in the Behavioral Risk Factor Surveillance System for adults, which is operated by state departments of health. More quantitatively precise measurements are being made by a few states and communities but personnel and financial resources for such surveys are limited. Nutritionists in state and local health agencies should explore the possibility of developing public-private partnerships with food producers, retailers, and marketers to collect information about dietary determinants and behaviors in states and communities. Better standardization of dietary assessment methods is needed, as is development of better methods to identify attitudes about diet and barriers to dietary improvement. Most important, though, dietary surveillance in states and communities must be more strongly tied to intervention programs intended to improve nutrition in those populations.

Adolescent↗
PubMed1997

Issues in the design and interpretation of studies of fatty acids and cancer in humans.

The methods used in nutritional epidemiology to study the relations between fatty acids and cancer risk include ecologic studies, case-control studies, cohort studies, and intervention trials examining either intermediate markers of cancer risk or cancer incidence. Each type of study design has its particular strengths and weaknesses. The inaccuracy of estimates of fatty acid intake from the use of dietary questionnaires linked to nutrient databases is a major limitation in nutritional epidemiology. Information on the concentrations of fatty acids in the circulation or in adipose tissue can complement estimations of dietary intake. Cancer prevention studies now underway are designed to test whole-diet effects on neoplasia and will not be able to separate the effects of specific fatty acids from those of other nutrients in the diet. The development of better intermediate markers of cancer risk could enable the use of experimental methods to assess the relation between specific fatty acids and cancer. Research findings as described in the literature are complicated both by the multiple hypotheses that can be tested when assessing fatty acid effects and by the uncertainties of multivariate adjustment. Although there are substantial obstacles to understanding the relations between fatty acid intakes and cancer risk, there is no better species than humans for inference about diet and cancer risk in people.

Dietary Fats↗
PubMed1997

Black/white differences in leukocyte subpopulations in men.

BACKGROUND: Although counts of leukocytes differ substantially between blacks and whites, and are predictive of ischaemic heart disease (IHD), racial differences in counts of leukocyte subpopulations have received less attention. METHODS: We examined black/white differences in leukocyte subpopulations among 3467 white and 493 black 31-45 year-old-men who had previously served in the US Army. Laboratory determinations were performed at a central location during 1985-1986. RESULTS: Black men had an 840 cell/microliter (or 15%) lower mean total leukocyte count than did white men, largely due to a 960 cell/microliter (or 25%) lower mean neutrophil count. Although black men also had a 20% lower mean monocyte count (= 70 cells/microliter) than did white men, their mean lymphocyte count was 10% higher (approximately = 200 cells/microliter). Counts of various leukocyte subpopulations were associated with cigarette smoking, haemoglobin levels, platelet counts, and several other characteristics, but black/white differences in counts of neutrophils, lymphocytes, monocytes and other subpopulations could not be attributed to any of the examined covariates. CONCLUSIONS: Despite the relatively low counts of leukocytes and neutrophils among black men, their lymphocyte counts are generally higher than those among white men. It is possible that black/white differences in counts of various cell types may influence race-specific rates of IHD, and future studies should attempt to assess the importance of leukocyte subpopulations in the development of clinical disease.

Adult↗
PubMed1997

Comparing two strategies to modify dietary behavior and serum cholesterol.

AIM: To test the hypothesis that a strategy including cholesterol screening and dietary education is more effective than dietary education alone in changing dietary behavior and serum cholesterol levels. METHODS: Individuals at four worksites were enrolled in a randomized trial with a 'full intervention' condition in which subjects were told their serum cholesterol value and also received a dietary change kit (n = 236), and a 'partial intervention' condition in which subjects received the same dietary change kit, but were not told their serum cholesterol value (n = 284). Individuals (n = 115) in two worksites served as a nonrandomized 'untreated control group'. Subjects were tested for serum cholesterol and completed a questionnaire at baseline, and 3 and 6 months later. RESULTS: Dietary changes occurred in seven of nine categories in individuals subjects to the full and partial interventions but in only one of nine categories in those studied in the control condition. Mean dietary intake differed between the full and partial intervention conditions for only three of nine dietary categories. Cholesterol level dropped in the full, partial and control conditions by 4.9, 3.9 and 9.6%, respectively. CONCLUSIONS: Dietary education has favorable effects on the dietary behaviors of individuals. Being told one's cholesterol level at the outset of this educational intervention has little effect on dietary change.

Adult↗
PubMed1996

Nutrition and cancer among American Indians and Alaska Natives.

BACKGROUND: More than a third of all cancers in the United States are thought to be attributable to various nutritional factors, and major changes in nutrition have been experienced by American Indians and Alaska Natives in the past century. METHODS: The published literature was reviewed to summarize the relationship between diet and cancer, to summarize what is known about the past and current diet of American Indians and Alaska Natives, and to consider whether nutrition might play a role in their current or future risk of cancer. RESULTS: Epidemiologic studies show a consistent pattern of lower risk for cancers of the colon and lung among those who eat larger amounts of fruits and vegetables and higher risk for cancers of the colon and prostate for those who eat larger amounts of fat. Limited data indicate that the diets of American Indians and Alaska natives are similar to the current average American diet, that is, high in fat and low in fruits and vegetables. CONCLUSIONS: Diet is an important factor for several major cancers. Although the cancer rates among many Native American groups are currently lower than among non-native Americans, they seem to be increasing. Cancer rates among Native Alaskans are already much higher than for non-native Americans. Nutrition-related cancers are likely to increase in the future among Native Americans as a result of past changes in diet. However, Native Americans may have a stronger cultural basis than do non-native Americans to adopt traditional principles of the value of good foods and physical activity to achieve future nutritional improvements to reduce cancer risk.

Alaska↗
PubMed1996

Baldness and ischemic heart disease in a national sample of men.

A weak positive association between male pattern baldness and ischemic heart disease has been suggested previously. The authors examined this issue by using data from the Epidemiologic Follow-up Study of the First National Health and Nutrition Examination Survey. As part of the baseline medical examination between 1971 and 1975, the presence and degree of male alopecia (none, minimal, moderate, and severe) were recorded for a subset of participants. Among 3,932 men aged 25-76 years who had complete data, 378 deaths and 939 incident events from ischemic heart disease occurred during an average follow-up period of 14 years. Among 2,019 men who were younger than age 55 years at baseline (61 deaths and 239 incident events of ischemic heart disease), severe baldness was positively associated with ischemic heart disease mortality (rate ratio = 2.51, 95 percent confidence interval 1.01-6.24) and somewhat less associated with ischemic heart disease incidence (rate ratio = 1.72, 95 percent confidence interval 0.96-3.08). No dose-response relation with degree of baldness was seen. Although these findings are tempered by the absence of information concerning the type of baldness (frontal or vertex), they provide support for earlier studies that indicate male pattern baldness that occurs before age 55 years may be by some mechanism related to ischemic heart disease.

Adult↗