The Multiple Risk Factor Intervention Trial was a randomized primary prevention trial to test the effect of a multifactor intervention program on mortality from coronary heart disease (CHD) in 12,866 high-risk men aged 35 to 57 years. Men were randomly assigned either to a special intervention (SI) program consisting of stepped-care treatment for hypertension, counseling for cigarette smoking, and dietary advice for lowering blood cholesterol levels, or to their usual sources of health care in the community (UC). Over an average follow-up period of seven years, risk factor levels declined in both groups but to a greater degree for the SI men. Mortality from CHD was 17.9 deaths per 1,000 in the SI group and 19.3 per 1,000 In the UC group, a statistically nonsignificant difference of 7.1% (90% confidence interval, -15% to 25%). Total mortality rates were 41.2 per 1,000 (SI) and 40.4 per 1,000 (UC). Three possible explanations for these findings are considered: (1) the overall intervention program, under these circumstances, does not affect CHD mortality; (2) the intervention used does affect CHD mortality, but the benefit was not observed in this trial of seven years' average duration, with lower-than-expected mortality and with considerable risk factor change in the UC group; and (3) measures to reduce cigarette smoking and to lower blood cholesterol levels may have reduced CHD mortality within subgroups of the SI cohort, with a possibly unfavorable response to antihypertensive drug therapy in certain but not all hypertensive subjects. This last possibility was considered most likely, needs further investigation, and lends support to some preventive measures while requiring reassessment of others.
OBJECTIVE:The purpose of the study was to evaluate two methods of dietary assessment for monitoring change in fat intake in a low-fat diet intervention study. DESIGN:The two dietary assessment methods were a 4-day food record (4DFR) and an unannounced 24-hour dietary recall conducted by telephone interview (referred to as a telephone recall [TR]). Subjects were assigned randomly to either a low-fat diet intervention group or a control group that received no counseling about fat intake. Dietary data were collected at baseline, 6 months, and 12 months. SUBJECTS:Two hundred ninety postmenopausal women with localized breast cancer were recruited at seven clinical centers in the United States. STATISTICAL ANALYSIS:Analysis of variance was used to test for significant differences in mean fat and energy intakes. RESULTS:Three sources of error were identified: (a) an instrument effect, suggesting underreporting at baseline of approximately 8% in mean energy intake and 11% in mean fat intake in the TR group compared with the 4DFR group (P = .0001); (b) a repeated measures effect observed for the 4DFR, suggesting underreporting of approximately 7% for energy intake and 14% for fat intake in the control group at 6 and 12 months compared with baseline values (P < .001); and (c) an adherence effect (or compliance bias), suggesting greater compliance to the low-fat intervention diet when subjects were keeping food records than when estimates were based on the unannounced TR. Compared with the TR, the 4DFR overestimated the extent of fat reduction in the low-fat diet intervention group by 41% (P = .08) and 25% (P = .62) at 6 and 12 months, respectively. APPLICATION:Multiple days of unannounced 24-hour recalls may be preferable to multiple-day food records for monitoring dietary change in diet intervention studies.
OBJECTIVE:To determine whether a food frequency questionnaire (FFQ) can detect changes in dietary intake before pregnancy to mid-pregnancy relative to a 4-day food record.DESIGN:FFQs and 4-day, weighed food records (4DRs) were completed during similar time intervals before pregnancy and again near mid-pregnancy by women served by a large health maintenance organization in the Minneapolis-St Paul, Minn, area. The outcome of interest was change in the intake of energy and 16 nutrients. Participants were members of the Diana Project, a prospective study of relationships among prepregnancy and pregnancy nutritional and other exposures and reproductive outcomes. Fifty-six (51%) of the eligible women completed the study.SUBJECTS:Well-educated, healthy, white women.STATISTICAL ANALYSES PERFORMED:Spearman rank order correlations.RESULTS:Mean energy and nutrient intake levels estimated using the 4DR were generally higher than those estimated using the FFQ. Correlations between change in energy and nutrient intakes measured by the 4DR and FFQ ranged from .75 for vitamin C to .02 for cholesterol and averaged .48.APPLICATIONS:Comparisons with 4DRs indicate that the FFQ used in this study is appropriate for obtaining reliable estimates of prepregnancy to mid-pregnancy changes in intake of energy and a number of nutrients in similar groups of women.
A list of research priorities related to dietary assessment methodology is presented. The priorities are based on a consensus of opinion by a multidisciplinary international group of experts who participated in the First International Conference on Dietary Assessment Methods. These experts included researchers in dietary assessment methodology, major users of dietary assessment methods, and policymakers involved in setting food and nutrition policies. The list of priorities may be used as a guide for planning future research in dietary assessment methods, for prioritizing the allocation of available research resources, and for planning subsequent conferences. A list of recommendations related to dietary assessment methodology is also presented. Procedures used by the conference planners to select the experts are described, and the need for developing objective criteria for ranking priorities is discussed. An ongoing function of the conference series will be to continue the process of revising the priorities and recommendations to reflect progress made and newly identified needs in dietary assessment methodology.
OBJECTIVE:To evaluate the reproducibility of a modified Burke-type diet history within the context of a long-term, randomized, 29-center clinical diabetes study.DESIGN:Diet histories were collected by trained interviewers at the end of years 1 and 2 after subjects were randomly assigned to the intensive treatment group or the conventional treatment group. Mean daily intakes of energy, protein, carbohydrate, total fat, saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, cholesterol, and dietary fiber were calculated for each treatment group at each time period.SUBJECTS:The study population consisted of 139 subjects in the intensive treatment group and 128 subjects in the conventional treatment group. Ages ranged from 13 to 39 years; groups included men and women. Distribution by age, sex, race, proportion of smokers, weight reported as percent ideal body weight, and duration of IDDM were similar in both groups.STATISTICAL METHODS:Differences in nutrient intake between the conventional and intensive treatment groups at each time period were tested for significance using the Wilcoxon rank-sum test. The Wilcoxon paired differences test was used to assess changes between time periods within treatment groups. Linear agreement between repeated administrations of the diet history was evaluated using Pearson's correlation coefficient, and the extent of within-subject reproducibility was assessed by intraclass correlation.RESULTS:No statistically significant differences in energy and nutrient intakes were observed between the two groups at either year 1 or year 2. Within each treatment group, energy and nutrient intake differences between times were not statistically significant. Correlation coefficients between years 1 and 2 ranged from .51 for dietary fiber to .72 for dietary cholesterol; within-subject reproducibility was slightly higher.APPLICATIONS:These results demonstrate long-term reproducibility for the meal-based diet history in the DCCT population.
The rationale for establishing an international conference series on dietary assessment methods is based on the needs expressed by numerous national and international organizations for better methods of collecting and analyzing dietary data. Dietary assessment is essential for investigating diet-health relationships, formulating policies to reduce health risks, predicting the adequacy of the food supply, and monitoring trends in food use, exposure to contaminants, and compliance with dietary guidelines. The conference rationale is discussed with respect to 1) the need for improved methods to enhance our understanding of diet-health relationships, 2) the need for better methods to facilitate development and monitoring of nutrition-related health objectives, and 3) the importance of international participation. Improved methods for assessing food intakes will enhance our understanding of the role of diet in the etiology and prevention of disease and will facilitate the development of nutrition policy and programs leading to improved health worldwide.
PURPOSE:To evaluate the feasibility of integrating a program based on dietary fat intake reduction into adjuvant treatment strategies for postmenopausal women receiving therapy for early breast cancer.PATIENTS AND METHODS:Two hundred ninety postmenopausal women with localized (stage I to IIIa) breast cancer receiving conventional systemic therapy provided informed consent and were randomized in a multicenter trial to either a dietary intervention group receiving a program of individualized instruction for reducing total fat intake or a dietary control group with minimal dietary counseling.RESULTS:Significantly reduced (P < .001) fat intake (in terms of percent calories derived from fat) was observed in the intervention group versus the control group at 3 months (20.3% +/- 2.4% v 31.5% +/- 2.6%, mean +/- SD, respectively) and maintained throughout 24 months of observation. The 50% reduction in daily fat-gram intake (from 66 +/- 23 to 33 +/- 14 g, P < .001) seen at 6 months was associated with reduced saturated fat, monounsaturated fat, polyunsaturated fat, and linoleic acid (P < .001). Significantly lower body weight was also seen in intervention compared with control patients at all observation periods, resulting in a 3.3-kg weight difference 18 months after randomization (P < .001).CONCLUSION:Substantial and sustained dietary fat reduction with associated weight change can be achieved at relatively low cost within the context of conventional multimodality clinical management of postmenopausal women with localized breast cancer. This result supports the feasibility of conducting a full-scale evaluation of the influence of dietary fat intake reduction on the clinical outcome of breast cancer patients.
Management of localized breast cancer now commonly involves a breast-sparing approach combined with systemic adjuvant therapy resulting in improved cosmetic results and patient survival. Reducing dietary fat intake represents a conceptually new approach to further improve outcome of patients with resected breast cancer. The rationale supporting evaluation of dietary fat reduction in the management of patients with localized breast cancer is based on: (1) epidemiologic observations (along with biochemical and hormonal correlates) of major differences in stage-by-stage survival of patients with localized breast cancer comparing outcome in countries with low fat (Japan) versus high fat (U.S.A.) dietary intakes; (2) relationships between dietary fat intake and factors prognostic of clinical outcome in patients with established breast cancer; (3) effects of weight gain (especially that associated with adjuvant chemotherapy) on breast cancer clinical outcome; (4) in vivo animal studies demonstrating adverse influence of increased dietary fat intake (especially linoleic acid) on growth and metastatic spread of mammary cancer; (5) direct adverse effects of increased linoleic acid on human breast cancer growth in vitro; (6) plausible mechanisms which could mediate the effects of dietary fat intake reduction on breast cancer growth and metastatic spread; (7) demonstration of adherence to dietary fat reduction regimens in ongoing clinical feasibility studies including those involving postmenopausal patients with resected breast cancer; and (8) favorable sample size requirements for definitive assessment of dietary fat intake reduction influence on breast cancer growth and metastases (using as endpoints relapse-free survival and overall survival) in postmenopausal breast cancer patients with localized disease.
With the growing number of nutrient-calculation software packages on the market, potential users are faced with the increasingly difficult task of determining which system best meets their needs. Most published reviews of nutrient-calculation software focus on program features rather than on the quality of the nutrient database on which all calculations are based. This is unfortunate because program features are of little consequence if the nutrients calculated are not of acceptable quality. The purpose of this paper is to focus on the evaluation of the nutrient database as the foremost consideration in selecting nutrient-calculation software. Six questions that may be used as a guide for evaluating a nutrient database are presented and discussed.