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Biomedical subjects

G Block

Publications and source records attributed to G Block.

At least 109 records · Page 6Linked to original sources
PubMed1989

A dietary and risk factor questionnaire and analysis system for personal computers.

The authors report the adaptation of a dietary and risk factor questionnaire and analysis system for use with IBM (or compatible) personal computers. This system includes a flexible computer-assisted interview program which may be modified to suit investigator needs while preserving a standard output format. It also includes a nutrient analysis program for calculation of usual dietary intake. Each of these two major components has its own set of utilities and options, so that investigators may tailor the system to particular research areas. The nature and capabilities of the two main programs are described, as well as the development of the underlying system and the general flow of data in the system.

Data Collection↗
PubMed1989

Validation of a retrospective questionnaire assessing diet 10-15 years ago.

In 1985, 216 men, participants in the Baltimore Longitudinal Study of Aging, were asked to report on their usual diet during the period 1971-1975. The reference data for past diet consisted of multiple seven-day records collected between 1971 and 1975. The group was randomly assigned to complete the diet history either by personal interview or by mailed self-administered questionnaire. The items and response categories were identical in both cases. For both groups, the mean nutrient intake estimated by questionnaire was within +/- 10 per cent of the past diet record values for most nutrients. When the questionnaire was administered by an interviewer, correlations with past diet were approximately as good as those obtainable with present diet in other studies and indicate that useful studies of past diet can be performed with this questionnaire. Correlations for the mail group were considerably lower and suggest that assessment of past diet using this questionnaire format without personal instruction or callbacks may yield poor results. The effect of age was negligible, but response errors and change in diet since the target period had important effects on correlations with past diet in both interview and mail groups.

Aged↗
PubMed1988

Cancer morbidity and mortality in phosphate workers.

Phosphate ore mining and processing operations are associated with dusty conditions and potential exposure to gamma radiation and radon daughter products. Although most current measurements are within Occupational Safety and Health Administration (OSHA) guidelines, no measurements exist for the era preceding modern standards of industrial hygiene and workplace ventilation. All workers employed by the participating phosphate company between 1950 and 1979 were ascertained, and 3451 males employed for approximately 6 months or more comprise the study population. Statistically significant elevations in lung cancer (standardized mortality ratio = 1.62) and emphysema were observed in white but not in black workers, in relation to U.S. rates. Among workers for whom 20 years had elapsed since first employment, there was a dose-response trend of increasing lung cancer risk with increasing duration of employment (standardized mortality ratio = 2.48 with 20 years of employment). There was no evidence of excess lung cancer risk among employees hired after 1960. Multivariate analyses and internal comparisons of risk by job type are consistent with a hypothesis of occupationally related lung cancer, but small numbers prevent firm conclusions.

Chemical Industry↗
PubMed1988

Dietary factors in oral and pharyngeal cancer.

A population-based case-control study of oral and pharyngeal cancer conducted in four areas of the United States provided information on a number of risk factors, including diet. Interviews were obtained from 871 oral cancer patients and 979 controls among whites, frequency matched for age and sex. Consumption frequency of 61 food items was assessed in the questionnaire; attention was given to foods that are sources of vitamins A and C and carotene. The major finding was an inverse relationship between fruit intake and risk of oral and pharyngeal cancer; individuals in the highest quartile of intake had about half the risk of those in the lowest quartile. Vitamin C, carotene, or fiber in fruit did not appear to account completely for this relationship, since these nutrients in vegetables did not provide similar protection. This finding suggests the influence of other constituents in fruits, although it is possible that cooking vegetables may have a nutrient-diminishing effect. Dietary intake of other nutrients, such as the B vitamins, vitamin E, folate, and iron, showed no consistent relationship to risk of oral and pharyngeal cancer. Coffee or other hot beverage consumption did not increase risk; intake of nitrite-containing meats or cooking practices, such as smoking, pickling, or charcoal grilling, also did not increase risk. All analyses were adjusted for the effects of tobacco and alcohol, strong risk factors for oral and pharyngeal cancer. Dietary findings among the few subjects who did not use tobacco or alcohol were similar to those for all subjects.

Adult↗
PubMed1988

Relation of changes in amount and type of dietary fat to fecapentaenes in premenopausal women.

Correlation studies suggest that fecal mutagenicity is increased in groups eating high-fat diets, the same groups who are often found to have high colorectal cancer incidence and mortality. The fecapentaenes are the best characterized class of fecal mutagens, but the relationship of dietary fat intake to the excretion of these potent genotoxins is unknown. We studied the effect of changes in amount and type of dietary fat on fecapentaene levels in 31 premenopausal women 20-40 years of age who participated in a controlled feeding study. After a pre-diet free-living period lasting 1 menstrual cycle, women were placed on a high-fat (40% energy from fat) diet for 4 menstrual cycles and then switched to a low-fat (20% energy from fat) diet for an additional 4 menstrual cycles. One-half the subjects were maintained throughout the study at a ratio of polyunsaturated-to-saturated fatty acids (P/S ratio) of 1.0, the other half at 0.3; body weight was constant. All meals during the controlled diet periods were prepared at the Human Study Facility of the Beltsville Human Nutrition Research Center. Fecapentaene and fecapentaene precursor levels were measured in acetone extracts from 3-day pooled stool samples collected during the study. No differences in fecapentaene or precursor levels were observed between the high- and low-fat diets at either P/S ratio. Fecapentaene and precursor levels were higher while on controlled diets than during the pre-diet free-living period, and levels declined again in the post-diet free-living period. We conclude that dietary fat has no significant effect on fecapentaene or precursor levels in acetone extracts of stool in premenopausal women. The effect of other dietary or non-dietary factors on fecapentaenes remains unknown.

Adult↗
PubMed1988

Vitamin supplement use, by demographic characteristics.

Detailed data on vitamin supplement use are presented for nine specific vitamins and minerals by a wide range of demographic and behavioral characteristics. Previously recorded but uncoded data from the first National Health and Nutrition Examination Survey (1971-1974) have been coded and analyzed, providing the only detailed vitamin use data in a representative sample large enough to examine joint distributions and multivariate analyses of numerous characteristics. Significantly fewer black persons than white persons consume vitamins regularly, and the difference is especially pronounced for specific vitamins: fourfold for vitamin E, sixfold for vitamin A, and 10-fold for vitamin C. Significant differences were also seen for age, sex, geographic region, education, poverty, type of alcoholic beverage consumed, and Quetelet index. Data are presented indicating that supplement use has not increased notably between the time of the survey and 1983, and thus the supplement use data are considered to be reasonably representative of current patterns of supplementation practice in the United States.

Adult↗
PubMed1988

Food choices and the cancer guidelines.

Twenty-four hour dietary recall data from 11,658 adult respondents in the second National Health and Nutrition Examination Survey (NHANES II) (1976-80) were used to examine the American diet in relation to certain of the cancer dietary guidelines from the National Academy of Sciences and the American Cancer Society. The per cent who reported consuming any food in those food groups considered protective was small: cruciferous vegetables (18 per cent); fruits and vegetables high in vitamin A (21 per cent); high fiber breads and cereals (16 per cent). The per cent consuming foods potentially increasing cancer risk was high: red meat (55 per cent); bacon and lunch meats (43 per cent). Proportions of persons eating fruits and vegetables increased with income. Diets were closer to the guidelines for females than males, for Blacks than Whites, and for older than younger Americans.

Adult↗
PubMed1988

Calories, fat and cholesterol: intake patterns in the US population by race, sex and age.

Nutrient intakes were investigated for Blacks and Whites using data from the NHANES II survey (1976-80). Intake of energy, total fat, saturated fat, dietary cholesterol, P/S ratio, and per cent of calories derived from total and saturated fat are examined by sex and age, both in absolute terms and per unit of body weight. For most age and sex categories, Blacks are found to have a lower intake of energy and fats than Whites; however, Blacks have a consistently higher intake of dietary cholesterol. The ratio of polyunsaturated fats to saturated fats is higher in females than in males, but all age-sex groups are substantially below recommended levels. Per cent of calories from total and saturated fat are similar in most age-sex groups. Possible explanations of the observed patterns include activity level and metabolic differences.

Adult↗
PubMed1987

Vitamin C intake and dietary sources by demographic characteristics.

Evidence from several lines of research indicates a role for vitamin C in the prevention of some types of cancer in addition to a possible role in hypercholesterolemia and other conditions. It is not yet clear, however, whether observed relationships are due to ascorbic acid alone or in conjunction with other constituents present in the foods containing ascorbic acid. A knowledge of the particular food sources of vitamin C in different demographic groups thus becomes important to fully understand the etiology. This information will also aid in planning effective education or intervention programs. This paper identifies the dietary sources of vitamin C by age, sex, race, and poverty status, using data from the second National Health and Nutrition Examination Survey (NHANES II). Orange juice is the leading dietary source in all subgroups, but the importance of other sources varies markedly by subgroup. Fortified foods are major contributors among the young but not the old, and southern greens are very important sources among blacks but not among whites. The intake of vitamin C is substantially lower among the poor. Potential relationships with disease are also discussed.

Age Factors↗
PubMed1987

Dietary fiber intake in the US population.

Twenty-four hour recall data from adults interviewed in the Second National Health and Nutrition Examination Survey, NHANES II, were used as the basis to estimate total dietary fiber intake in the United States. Food fiber values were calculated for the 2500 foods in NHANES II in two ways: 1) using fiber values compiled from the literature by NCI and 2) values based on the Southgate methodology. Mean dietary fiber intake in the US adult population (greater than 19 y of age) is 11.1 g/d using the first set of values and 13.3 g/d according to Southgate values. On a per 1000 kcal basis, women consume more dietary fiber (6.5 g/1000 kcal) than men (5.5 g/1000 kcal) at every age. Fiber intake by geographic region, age, race, and sex is discussed. Our study indicates that dietary fiber intake in the United States is considerably lower than that previously reported.

Adult↗
PubMed1987

Evaluation of two food frequency methods of measuring dietary calcium intake.

To assess the ability of food frequency methods to measure current dietary calcium intake in elderly women, the authors administered two types of food frequency instruments to 37 randomly selected women who attended two senior citizens centers in San Francisco, and they compared those responses to seven-day food records. A 34-item food frequency instrument (with portion sizes rated as small, medium, or large) correlated well (r = 0.76) with the estimated calcium intake from seven-day records. Limiting the instrument to the top 15, 10, or five foods that contribute to dietary calcium intake had little effect on this correlation (r = 076, 0.75, and 0.67, respectively). Rating all portions as "medium" reduced these correlations somewhat. An 18-item instrument, which asks respondents to rate portion sizes in ounces or cups, did not correlate as well with the seven-day records (r = 0.49). The authors conclude that brief food frequency instruments which rate portion sizes on a simple qualitative scale may be suitable for many clinical uses and adequate for some types of epidemiologic studies of calcium intake in elderly women.

Aged↗
PubMed1987

Dietary fiber sources in the United States by demographic group.

Major food sources of total dietary fiber are presented for the whole U.S. population and by age, sex, and race. Revised data on fiber content were applied to dietary intake data from the Second National Health and Nutrition Examination Survey, a representative sample of the U.S. population examined in 1976-80. Vegetables are the principal sources of dietary fiber, followed by bread and fruit. Legumes are important population sources and rank first for several age-sex-race categories when food groups are broken down into more detailed food items. Breakfast cereals make considerably lesser contributions. Data on fiber intake in several age, sex, and race groups are also presented.

Adult↗
PubMed1987

Dietary fat and breast cancer in the National Health and Nutrition Examination Survey I Epidemiologic Follow-up Study.

The relationship between dietary fat intake and breast cancer incidence was examined in the National Health and Nutrition Examination Survey I (NHANES I) Epidemiologic Follow-up Study cohort. This cohort is derived from adults (greater than or equal to 25 yr) examined in the NHANES I (1970-75) cross-sectional survey of the U.S. population and provides a mean follow-up time of 10 years. An analytic sample of 5,485 women, including 99 breast cancer cases (34 premenopausal and 65 postmenopausal at NHANES I baseline), was examined for associations with dietary intake of fat, percent energy from fat, total energy, saturated fat, polyunsaturated fat, monounsaturated fat, and cholesterol on the basis of a 24-hour recall administered at the baseline NHANES I examination. No significant differences in dietary fat intake between cases and noncases were evident when mean intakes for each group were compared. For total fat (g) and saturated fat (g), a significant inverse association was indicated in proportional hazards analyses. Adjustment of fat for total energy intake resulted in a smaller effect that was no longer statistically significant. Adjustment for accepted breast cancer risk factors did not change these findings. This prospective study of a sample from the U.S. population does not support the hypothesis that high dietary fat intake increases breast cancer risk. Indeed, some lower risk associated with high fat intake may be indicated, although this result may be influenced by methodologic problems with the dietary assessment.

Adult↗
PubMed1986

A data-based approach to diet questionnaire design and testing.

A self-administered diet history questionnaire has been developed for epidemiologic and clinical use. Both the food list and the nutrient values to be associated with it were developed using dietary data from 11,658 adult respondents to the Second National Health and Nutrition Examination Survey (NHANES II). Food items were selected on the basis of their contribution to total population intake of energy and each of 17 nutrients in the NHANES II data, and represent over 90% of each of those nutrients. Associated nutrient composition values were determined from the NHANES II database using frequency of consumption data in that survey. Portion sizes to be associated with each food item were derived from observed portion size distributions in NHANES II, based on three-dimensional models. The resulting food list and its corresponding brief data base, when used to calculate nutrients from a diet record, yielded correlations of r greater than 0.70 with the more detailed method. Field administration produced mean values comparable to national data.

Adult↗
PubMed1986

Locus of control and smokeless tobacco use among adolescents.

Seventh-grade students from two school districts in rural North Carolina were surveyed to determine the prevalence and correlates of smokeless tobacco use. The survey was carried out as part of a larger project intended to study prevalence of "risky" behaviors, specifically alcohol and tobacco use. Data were collected from 322 students: 49% male, 36.6% nonwhite. Of those reporting use of smokeless tobacco (11.4%), virtually all were male; most reported weekly use, with a small proportion (1.3%) reporting daily use. Locus of control of "occasional" users was significantly more internal than those reporting "regular" use (p less than .05).

Adolescent↗
PubMed1985

Nutrient sources in the American diet: quantitative data from the NHANES II survey. I. Vitamins and minerals.

Dietary data from 11,658 adult respondents in the second National Health and Nutrition Examination Survey were used to provide quantitative information regarding the contribution of specific foods to the total population intake of the following 10 nutrients: vitamin A, thiamine, riboflavin, niacin, vitamin C, iron, phosphorus, calcium, sodium, and potassium. Data are reported in the companion paper regarding the number of adults in the US population consuming each of 147 food items, representing all foods reported by these respondents. The percentage of total nutrient intake which each food provides is presented for the top 50 contributors of each of the nutrients listed above. Foods sometimes overlooked as important sources are found in some instances to be quantitatively important to population intake, such as spaghetti dishes as an independent source of carotenoids. These data should be useful to epidemiologists with a substantive interest in dietary etiologies or a methodological interest in the development of dietary assessment instruments. In addition, they may be useful to health care planners or nutrition educators.

Adult↗