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Biomedical subjects

T Byers

Publications and source records attributed to T Byers.

At least 109 records · Page 6Linked to original sources
PubMed1992

Weight loss attempts in adults: goals, duration, and rate of weight loss.

OBJECTIVES: Although attempted weight loss is common, little is known about the goals and durations of weight loss attempts and the rates of achieved weight loss in the general population. METHODS: Data were collected by telephone in 1989 from adults aged 18 years and older in 39 states and the District of Columbia. Analyses were carried out separately for the 6758 men and 14,915 women who reported currently trying to lose weight. RESULTS: Approximately 25% of the men respondents and 40% of the women respondents reported that they were currently trying to lose weight. Among men, a higher percentage of Hispanics (31%) than of Whites (25%) or Blacks (23%) reported trying to lose weight. Among women, however, there were no ethnic differences in prevalence. The average man wanted to lose 30 pounds and to weigh 178 pounds; the average woman wanted to lose 31 pounds and to weigh 133 pounds. Black women wanted to lose an average of 8 pounds more than did White women, but Black women's goal weight was 10 pounds heavier. The average rate of achieved weight loss was 1.4 pounds per week for men and 1.1 pounds per week for women; these averages, however, may reflect only the experience of those most successful at losing weight. CONCLUSIONS: Attempted weight loss is a common behavior, regardless of age, gender, or ethnicity, and weight loss goals are substantial; however, obesity remains a major public health problem in the United States.

Adolescent↗
PubMed1992

Tracking of serum cholesterol levels in a multiracial sample of preschool children.

The relation of an initial measurement of serum total cholesterol to subsequent levels over a (mean) 13-month interval was examined in a multiracial (white, Hispanic, American Indian, and black) sample of 1680 one- to four-year-olds. Although the relation of the initial level to the final measurement (r = .54) did not vary by race, sex, relative weight, or changes in relative weight, the association increased with age at the time of the initial measurement (eg, r = .64 among 4-year-olds). Based on the initial and final total cholesterol determinations, the within-person standard deviation was 21 mg/dL and the coefficient of variation was 13%. Although the final total cholesterol level was within 5 mg/dL of the initial level for 18% of the children, the two determinations differed by greater than or equal to 25 mg/dL for about 35% of the children and by greater than or equal to 50 mg/dL for about 8%. Of the 149 children who had an initial cholesterol level greater than or equal to 200 mg/dL, 34% (about five times the expected number) had a follow-up level that was similarly elevated whereas 25% had a subsequent measurement below 170 mg/dL. The results indicate that although an initial cholesterol level in early life is moderately predictive of subsequent levels, it may be difficult to interpret a single total cholesterol determination because of substantial within-person variability.

Child, Preschool↗
PubMed1991

Smoking cessation and severity of weight gain in a national cohort.

BACKGROUND: Many believe that the prospect of weight gain discourages smokers from quitting. Accurate estimates of the weight gain related to the cessation of smoking in the general population are not available, however. METHODS: We related changes in body weight to changes in smoking status in adults 25 to 74 years of age who were weighed in the First National Health and Nutrition Examination Survey (NHANES I, 1971 to 1975) and then weighed a second time in the NHANES I Epidemiologic Follow-up Study (1982 to 1984). The cohort included continuing smokers (748 men and 1137 women) and those who had quit smoking for a year or more (409 men and 359 women). RESULTS: The mean weight gain attributable to the cessation of smoking, as adjusted for age, race, level of education, alcohol use, illnesses related to change in weight, base-line weight, and physical activity, was 2.8 kg in men and 3.8 kg in women. Major weight gain (greater than 13 kg) occurred in 9.8 percent of the men and 13.4 percent of the women who quit smoking. The relative risk of major weight gain in those who quit smoking (as compared with those who continued to smoke) was 8.1 (95 percent confidence interval, 4.4 to 14.9) in men and 5.8 (95 percent confidence interval, 3.7 to 9.1) in women, and it remained high regardless of the duration of cessation. For both sexes, blacks, people under the age of 55, and people who smoked 15 cigarettes or more per day were at higher risk of major weight gain after quitting smoking. Although at base line the smokers weighed less than those who had never smoked, they weighed nearly the same at follow-up. CONCLUSIONS: Major weight gain is strongly related to smoking cessation, but it occurs in only a minority of those who stop smoking. Weight gain is not likely to negate the health benefits of smoking cessation, but its cosmetic effects may interfere with attempts to quit. Effective methods of weight control are therefore needed for smokers trying to quit.

Adult↗
PubMed1991

Trends in alcohol consumption by pregnant women. 1985 through 1988.

To examine trends in alcohol consumption among pregnant women, we examined data collected from 21 states participating in the Behavioral Risk Factor Surveillance System for 4 consecutive years: 1985 through 1988. Overall, 429 (25%) of 1712 pregnant women and 19,903 (55%) of 36,057 nonpregnant women 18 to 45 years of age reported using alcohol in the previous month. Pregnant women who used any alcohol reported consuming a median of four drinks per month, whereas nonpregnant women who used any alcohol reported nine. The prevalence of alcohol consumption among pregnant women declined steadily, from 32% in 1985 to 20% in 1988, but the median number of drinks per month for pregnant women who drank did not change. No decline was observed among the less educated or those under the age of 25 years. In 1988, the prevalence of alcohol use among pregnant women remained highest among smokers (37%) and the unmarried (28%). Although the overall consumption of alcohol by pregnant women in the United States appears to be declining, special efforts are needed to reduce alcohol use among pregnant women who are smokers, unmarried, less educated, or younger, women who may already be at high risk of a poor pregnancy outcome.

Adolescent↗
PubMed1991

Associations between breast cancer, plasma triglycerides, and cholesterol.

A case-control study investigating the association between plasma lipids and breast cancer was conducted among women aged 30-80 in Buffalo, NY. All eligible women from a large breast clinic and two area physicians' offices were requested to participate over a one-year period. Subjects completed a health questionnaire and donated a fasting blood sample prior to diagnostic breast biopsies. The 83 women found to have breast cancer (cases) had significantly higher plasma triglyceride values than did the 113 women found not to have breast cancer (controls). Lower plasma beta-carotene values were associated with breast cancer, but only in those women with elevated triglyceride or cholesterol. Plasma cholesterol values were lower in those breast cancer cases presenting with more advanced stages of cancer, suggesting that metabolic effects of clinical and preclinical breast cancer may lower cholesterol levels. Although the limitations of case-control studies are well-recognized, these data suggest an etiologic role for plasma triglycerides and beta-carotene or for related dietary factors.

Adult↗
PubMed1991

The 10-y incidence of obesity and major weight gain in black and white US women aged 30-55 y.

Although the prevalence of obesity in US women is well-described, data are limited on the incidence of major weight gain and obesity. We used data from the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study to estimate the 10-y incidence of major weight gain (greater than or equal to 10 kg) and obesity [body mass index (BMI, in kg/m2) greater than or equal to 29] in a cohort of US women aged 30-55 y (n = 535 blacks and 2976 whites). In women not obese at baseline, blacks were 60% more likely to become obese than whites [incidence in blacks = 15.5%, 95% confidence interval (CI) = 11.2-19.7; incidence in whites = 9.7%, 95% CI = 8.6-10.8]. This higher incidence of obesity in blacks was largely due to their higher average BMI at baseline. The incidence of major weight gain was 50% higher in blacks than in whites (in blacks, 17.3%; 95% CI = 13.6-21.0; in whites, 11.7%; 95% CI = 10.3-13.1). We estimate that in black and white women, respectively, 16% and 12% of coronary heart disease is attributed to major weight gain whereas 35% and 21% is attributed to being obese.

Adult↗
PubMed1990

Breast cancer and dietary and plasma concentrations of carotenoids and vitamin A.

A case-control study of breast cancer was conducted in Buffalo. Participants completed a food frequency questionnaire and donated a fasting blood sample before definitive workup for breast masses. Dietary and plasma concentrations of carotenoids and retinol for 83 women found to have breast cancer were compared with those of 113 women found to be free of breast cancer (control subjects). There were no case-control differences in dietary estimates of vitamin A intake or in plasma alpha-carotene and lycopene. However, subjects with breast cancer had lower concentrations of plasma beta-carotene than did control subjects (P = 0.02). There was no overall association between plasma retinol and breast cancer but a positive relationship was observed between retinol and breast cancer in the subgroup with low beta-carotene values. These results suggest that low plasma beta-carotene is associated with increased risk of breast cancer. Other studies will need to determine whether low carotene concentrations are a subtle effect of the disease or might be causally related to breast cancer.

Adult↗
PubMed1989

Ambient 60-Hz magnetic flux density in an urban neighborhood.

A residential neighborhood in Buffalo, NY, was surveyed with a magnetic field meter to evaluate whether or not spot measurements are reliable predictors of the 60-Hz fields at street corners and residences. The results of repeated measurements over 7 days at 33 street corners in this neighborhood indicate that day-to-day variation in power line magnetic fields is negligible (intraclass correlation coefficient = 0.94). Multivariate linear regression analysis of the data indicates that transmission lines and thick, three-phase primary wires near the field measurement site are strong predictors and account for the majority of the ambient magnetic field variance between locations (multiple correlation coefficient squared = 0.60; F ratio = 22.2, P less than .001). Magnetic fields measured at the front sidewalk were highly correlated with fields at the front doorsteps of 45 homes in this neighborhood (gamma = 0.81). These results suggest that ambient power line magnetic field levels at urban residences can be reliably characterized on a one-time site inspection using a hand-held magnetic field meter and a simple wiring classification system.

Electric Power Supplies↗
PubMed1988

Diet and cancer. Any progress in the interim?

It has been 5 years since the National Research Council (NRC) Committee on Diet, Nutrition and Cancer published "Interim Dietary Guidelines" for the nutritional prevention of cancer. The term "interim" implies that these recommendations should be regarded as temporary, pending more definitive findings from additional scientific research. This article reviews findings relevant to the connections between diet and cancer that have emerged from nutritional epidemiology subsequent to the 1982 the NRC report. Some recent research has supported the earlier work which served as a basis for the interim recommendations, some has not, and additional hypotheses have emerged. There continues to be evidence, although it is inconsistent, that dietary fat may be an important factor in colon cancer, and that something related to fruits and vegetables, perhaps carotene, may lower the risk of lung cancer. However, the hypothesized relationships between dietary fat and breast cancer and between dietary fiber and colon cancer have been less consistently supported by new findings. Meanwhile, a new hypothesis has emerged relating alcohol intake to breast cancer risk, although many important questions remain regarding the age at which alcohol use may affect risk, and the dose above which risk is increased. The last 5 years seem to have been characterized by only slow progress in our understanding of the relationship between diet and cancer. It is clear that in 1988 we are still very much in the interim. Critical methodologic assessments of the reasons for the discrepancies in findings among the various studies, and meta analytic approaches may be helpful in increasing our understanding of the set of epidemiologic research conducted to date. More important, however, are the many types of studies now underway, including more rigorously designed observational studies and chemo-preventive and dietary-preventive trials. These studies will likely provide more definitive future answers to the questions we still face in the interim.

Alcohol Drinking↗
PubMed1988

Dietary epidemiology of cancer of the colon in western New York.

The authors interviewed 428 pathologically confirmed cases of colon cancer and controls matched on age, sex, race, and neighborhood in the New York counties containing the cities of Buffalo, Niagara Falls, and Rochester. Risk of colon cancer in both males and females, studied separately, appeared to increase with the amount of total fats and total calories ingested. In addition, we found the risk to increase with increases in the Quetelet index of relative weight (weight (kg)/height (m)2). Dietary fiber was only equivocally associated with risk. Fats and Quetelet index were associated with increased risk in a regression analysis adjusting each factor for the other, as well as for fiber, age, and socioeconomic status. The same was true for calories and Quetelet index. Future efforts to clarify a possible protective role for fiber and to disentangle the effects of fats and calories need to be undertaken. The fact that calories ingested and obesity are each associated with increased risk suggests the importance of studying calorie expenditure.

Body Height↗
PubMed1988

Relationships between laterality of congenital upper limb reduction defects and school performance.

Eighty children (34 males, 46 females) with congenital upper limb reduction defects who attended a regional amputee clinic between 1956 and 1986 were classified as to whether they exhibited learning difficulties in school, as indicated by grade failure or by placement in learning disability classrooms. Children with right-sided defects were more likely to encounter learning difficulties than were children with left-sided defects (Chi-square = 6.8; df = 1; p less than 0.01). Children with right-limb defects also were more likely than children with left-limb defects to experience reading problems (Chi-square = 5.9; df = 1; p less than 0.05). These results suggest the need for neuropsychological and neurophysiological study of children with limb reduction defects.

Arm↗
PubMed1987

The reliability of dietary history from the distant past.

A major barrier to the conduct and interpretation of retrospective studies of diet and cancer has been uncertainty about the reliability of retrospective measures of diet from the distant past. The authors therefore conducted a study to assess the reliability of retrospective dietary reports and to determine whether the retrospective report or the report of current diet is the better indicator of past diet. Persons (n = 323) originally interviewed regarding their diets in 1975-1979 were retrospectively reinterviewed in 1984-1985. There was little difference between the retrospective reports and the reports of current diet when group means were examined as indicators of past diet. The retrospective reports tended to overestimate the past frequency of consumption for most foods, whereas the reports of current diet tended to yield underestimates. Because food frequency-based dietary history data are more useful for ranking study subjects than for generating estimates of group means, correlation analysis was used as the principal assessment of the reliability of the two indicators of past diet. The retrospective reports more closely correlated with the diet reported at the original interview than did the report of current diet (for 37 of 47 foods). Nutrient indices based on the retrospective history were also more highly correlated with those of the original diet than were indices based on the current diet. No differences were noted in the reliability of retrospective reports according to age or sex. Subjects accurately reported perceptions of changes in their consumption of most foods, yet an estimate of past diet created by adjusting current diet for perceived change did not correlate more highly with the original diet than did the retrospective report. The authors conclude that assessing current diet to make inference about diet from the distant past does not yield more reliable estimates of past diet than does the retrospective dietary history. The best estimate of diet from several years in the past may be derived directly from a retrospective dietary history which focuses on that past period of time.

Aged↗
PubMed1986

Dietary vitamin A and cancer--a multisite case-control study.

The relationship between an index of dietary vitamin A and cancer risk at 25 sites was assessed in retrospective case-control studies. Common control groups for males and females were used in all analyses. Relative risk estimates were derived from multiple logistic regression analyses that controlled for age, alcohol consumption, and smoking exposure. We found that among males, dietary vitamin A is associated with lower risk for cancers of the tongue, floor and other mouth, pharynx, larynx, esophagus, and lung but higher risk for Hodgkin's disease and leukemia. Among females, we found that dietary vitamin A had less effect on risk generally but was associated with lower risk for bladder cancer. These findings are consistent with previous research that showed dietary vitamin A to be associated with decreased risk of squamous epithelial cancers. The association of dietary vitamin A and increased risk of Hodgkin's disease and leukemia among males in addition to the disparity in effect of dietary vitamin A on risk between males and females are areas worthy of further research.

Adult↗
PubMed1986

Cigarette smoking in women with cancers of the breast and reproductive organs.

This case-control study addressed the relationship between cigarette smoking and cancers of the breast (1,741 cases), endometrium (476 cases), uterine cervix (1,174 cases), and ovary (296 cases). The lifetime smoking history of cases was compared with that of 2,128 controls, and relative risks (odds ratios) for smoking were estimated using multiple logistic regression to adjust for potential confounding by age, marital status, number of pregnancies, and Quetelet's index. With increasing amount smoked there was a statistically significant decrease in endometrial cancer risk and a statistically significant increase in cervical cancer risk. In the highest smoking category (greater than or equal to 15 pack-yr), the endometrial cancer relative risk was 0.57 [95% confidence interval (CI) of 0.37, 0.86] and the cervical cancer relative risk was 1.81 (95% CI of 1.47, 2.22). There was no apparent relationship between smoking and cancers of the breast or ovary.

Adult↗