Sally F. Schakel

INTERMAP: the dietary data--process and quality control.

The aim of this report is to describe INTERMAP standardized procedures for assessing dietary intake of 4680 individuals from 17 population samples in China, Japan, UK and USA: Based on a common Protocol and Manuals of Operations, standardized collection by centrally trained certified staff of four 24 h dietary recalls, two timed 24-h urines, two 7-day histories of daily alcohol intake per participant; tape recording of all dietary interviews, and use of multiple methods for ongoing quality control of dietary data collection and processing (local, national, and international); one central laboratory for urine analyses; review, update, expansion of available databases for four countries to produce comparable data on 76 nutrients for all reported foods; use of these databases at international coordinating centres to compute nutrient composition. Chinese participants reported 2257 foods; Japanese, 2931; and UK, 3963. In US, use was made of 17 000 food items in the online automated Nutrition Data System. Average time/recall ranged from 22 min for China to 31 min for UK. Among indicators of dietary data quality, coding error rates (from recoding 10% random samples of recalls) were 2.3% for China, 1.4% for Japan, and UK; an analogous US procedure (re-entry of recalls into computer from tape recordings) also yielded low discrepancy rates. Average scores on assessment of taped dietary interviews were high, 40.4 (Japan) to 45.3 (China) (highest possible score: 48); correlations between urinary and dietary nutrient values—similar for men and women—were, for all 4680 participants, 0.51 for total protein, range across countries 0.40–0.52; 0.55 for potassium, range 0.30–0.58; 0.42 for sodium, range 0.33–0.46. The updated dietary databases are valuable international resources. Dietary quality control procedures yielded data generally indicative of high quality performance in the four countries. These procedures were time consuming. Ongoing recoding of random samples of recalls is deemed essential. Use of tape recorded dietary interviews contributed to quality control, despite feasibility problems, deemed remediable by protocol modification. For quality assessment, use of correlation data on dietary and urinary nutrient values yielded meaningful findings, including evidence of special difficulties in assessing sodium intake by dietary methods.

Enhancing data on nutrient composition of foods eaten by participants in the INTERMAP study in China, Japan, the United Kingdom, and the United States

The International Study of Macronutrients and Blood Pressure (INTERMAP) is a four-country study investigating relationships between individual dietary intakes and blood pressure. Dietary intake patterns of individuals were estimated for macronutrients (proteins, lipids, carbohydrates, alcohol) and their components (amino acids, fatty acids, starch), as well as minerals, vitamins, caffeine, and dietary fiber. The dietary assessment phase of the study involved collection of four 24-h recalls and two 24-h urine specimens from each of 4680 adults, ages 40-59, at 16 centers located in the Peoples Republic of China, Japan, the United Kingdom and the United States. For each country, an available database of nutrient composition of locally consumed foods was updated for use in the analysis of dietary data collected within the country. The four original databases differed in number and types of foods and nutrients included, analytic methods used to derive nutrients, and percentage of missing nutrient values. The Nutrition Coordinating Center at the University of Minnesota updated the original databases in several ways to overcome the foregoing limitations and increase comparability in the analyses of nutrient intake of individuals across the four countries: (1) addition of new foods and preparation methods reported by study participants; (2) addition of missing nutrient fields important to the study objectives; (3) imputation of missing nutrient values to provide complete nutrient data for each food reported by participants; and (4) use of adjustment factors to enhance comparability among estimates of nutrient intake obtained through each countrys nutrient-coding methodology. It was possible to expand, enhance, and adjust the nutrient databases from the four countries to produce comparable (60 nutrients) or nearly comparable (ten nutrients) data on composition of all foods reported by INTERMAP participants.

Trends in the trans-fatty acid composition of the diet in a metropolitan area: The Minnesota Heart Survey

OBJECTIVE In this study, we examine trends in dietary intake of trans-fatty acids from 1980-1982 to 1995-1997 using data collected as part of the Minnesota Heart Survey (MHS). DESIGN The MHS is an ongoing observational epidemiologic study among independent cross-sectional probability samples of adults. Twenty-four-hour dietary recalls were collected on a subset of participants. To obtain trans-fatty acid intake estimates, the dietary recall records were recalculated using the University of Minnesota Nutrition Coordinating Center Food and Nutrient Database. Subjects/setting The survey population included noninstitutionalized adults aged 25 to 74 years residing in the Minneapolis-St. Paul, MN, metropolitan area. Statistical analysis Mean intake estimates were generated for each survey, and a generalized linear mixed model was used to test the null hypothesis of no difference in the age-adjusted sex-specific means between 1980-1982, 1985-1987, 1990-1992, and 1995-1997. RESULTS Downward trends in dietary intake of trans-fatty acids were found between 1980-1982 and 1995-1997. For example, for men mean intake of total trans-fatty acids declined from 8.3 g per day in 1980-1982 to 6.2 g per day in 1995-1997 (P<.001). Represented as a percentage of energy, similar declines were seen with mean intake of total trans-fatty acids decreasing from 3.0% of total energy in 1980-1982 to 2.2% of total energy in 1995-1997 (P<.001). APPLICATIONS/CONCLUSIONS It seems that intake of trans-fatty acids is on the decline. Consideration should be given to additional changes in the food supply and consumer food choices that may result in further reduction in consumption of trans-fatty acids.

Maintenance of a nutrient database for clinical trials

Maintenance of a nutrient database for use in dietary analysis for clinical trials and other medical research studies is described. The database, maintained at the University of Minnesotas Nutrition Coordinating Center (NCC), has been used to calculate dietary intake data for a wide range of diet-disease related investigations including studies on cardiovascular disease, hypertension, cancer, gastroenterology, and osteoporosis. Potential sources of error associated with nutrient databases are identified. Criteria are provided for the selection of a nutrient database to meet study objectives and to minimize the potential for errors and inconsistencies. NCC database maintenance procedures, designed to provide updated and verified nutrient calculations for clinical research, involve adherence to standardized procedures for all aspects of database maintenance including data selection, imputations, quality control, recipe calculations, and documentation. By maintaining multiple versions of the database, the NCC is able to update and expand a working version of the database while providing database stability for individual research studies.

A validation study on food composition tables for the international cooperative INTERMAP study in Japan.

ObjectiveThe INTERMAP Study is an international cooperative study on the relationship between macro- and micro-nutrient intakes and blood pressure. The present study—ancillary to INTERMAP—is to evaluate validity of the INTERMAP Tables of Food Composition in Japan (ITJ) formulated by modifying the Standard Tables of Food Composition in Japan (STJ), including factoring in changes in weight and nutrient composition of individual foods due to cooking.MethodsWith chemical analytical values of 96 meals prepared in two university hospitals in Japan as the “gold standard”, validity of calculated values based on the ITJ was examined for six major components (energy, protein, lipid, carbohydrate, sodium, potassium) by comparison of mean values, correlation, and linear regression analysis.ResultsAlthough both the ITJ-based and STJ-based calculated values for all six components were significantly higher than the analytical values, differences from the analytical values were generally less marked for the ITJ-based values than for the STJ-based values. The STJ-based values were significantly higher than the ITJ-based values for protein and potassium. Analytical values showed slightly stronger correlations with the ITJ-based calculated values (r=0.876 for total energy, r=0.789 for lipid, r=0.832 for potassium) than with the STJ-based calculated values, except for carbohydrates.ConclusionsThe ITJ was considered to have greater validity than the STJ. To obtain more accaurate data in nutritional surveys, food composition tables in which changes in nutrient compositions due to cooking methods are taken into consideration should be used.

Appendix 1. Nutrient-Composition Tables for Grains and for Grain-Based Products

The composition of grains and grain-based foods is provided with respect to protein; carbohydrate; fat; fiber; the minerals potassium, sodium, calcium, iron, phosphorus, zinc, copper, magnesium, vitamin A, thiamin, riboflavin, niacin, folate, pantothenic acid, and vitamin B 6 , based on the specified serving portions. Data are provided for grains, flours, meals, and foods including breads, cookies, cakes, pasta, pies, and beverages.

Nutrient-Composition Tables for Grains and for Grain-Based Products

The composition of grains and grain-based foods is provided with respect to protein; carbohydrate; fat; fiber; the minerals potassium, sodium, calcium, iron, phosphorus, zinc, copper, magnesium, vitamin A, thiamin, riboflavin, niacin, folate, pantothenic acid, and vitamin B 6 , based on the specified serving portions. Data are provided for grains, flours, meals, and foods including breads, cookies, cakes, pasta, pies, and beverages.

Food composition database harmonization for between-country comparisons of dietary data in the TEDDY Study

Prevalence of lipid abnormalities before and after the introduction of lipid modifying therapy among Swedish patients with type 2 diabetes and/or coronary heart disease (PRIMULA Sweden)In the ACTION (A Coronary disease Trial Investigating Outcome with Nifedipine GITS) trial, the benefits of adding nifedipine GITS to the treatment of patients with stable symptomatic coronary artery disease were particularly apparent in those with concomitant hypertension. This further analysis has assessed whether or not the addition of nifedipine GITS is particularly beneficial in the treatment of patients with the combination of diabetes mellitus and chronic stable angina.Different sets of risk factors for the development of albuminuria and renal impairment in type 2 diabetes : the Swedish National Diabetes register (NDR)