Nutrient intakes of middle-aged men and women in China, Japan, United Kingdom, and United States in the late 1990s: the INTERMAP study.

The purpose of the study was to compare nutrient intakes among Chinese, Japanese, UK, and US INTERMAP samples, and assess possible relationships of dietary patterns to differential patterns of cardiovascular diseases between East Asian and Western countries. Based on a common Protocol and Manuals of Operations, high-quality dietary data were collected by four standardized 24-h dietary recalls and two 24-h urine collections from 17 population samples in China (three samples), Japan (four samples), UK (two samples), and USA (eight samples). There were about 260 men and women aged 40-59 years per sample--total N=4680. Quality of dietary interview and data entry were monitored and enhanced by extensive systematic ongoing quality control procedures at local, country, and international level. Four databases on nutrient composition of foods from the four countries were updated and enhanced (76 nutrients for all four countries) by the Nutrition Coordinating Center, University of Minnesota, in cooperation with Country Nutritionists. The mean body mass index was much higher for Western than East Asian samples. Macronutrient intakes differed markedly across these samples, with Western diet higher in total fat, saturated and trans fatty acids, and Keys dietary lipid score, lower in total carbohydrate and starch, higher in sugars. Based on extensive published data, it is a reasonable inference that this pattern relates to higher average levels of serum total cholesterol and higher mortality from coronary heart disease in Western than East Asian populations. The rural Chinese diet was lower in protein, especially animal protein, in calcium, phosphorus, selenium, and vitamin A. Dietary sodium was higher, potassium lower, hence Na/K ratio was higher in the Asian diet, especially for Chinese samples. This pattern is known to relate to risks of adverse blood pressure level and stroke. At the end of the 20th century, East Asian and Western diets remain significantly different in macro- and micronutrient composition. Both dietary patterns have aspects that can be regarded, respectively, as adverse and protective in relation to the major adult cardiovascular diseases. In both Asian and Western countries, public efforts should be targeted at overcoming adverse aspects and maintaining protective patterns for prevention and control of cardiovascular diseases.

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.

Higher blood pressure in middle-aged American adults with less education-role of multiple dietary factors: the INTERMAP study.

Extensive evidence exists that an inverse relation between education and blood pressure prevails in many adult populations, but little research has been carried out on reasons for this finding. A prior goal of the INTERMAP Study was to investigate this phenomenon further, and to assess the role of dietary factors in accounting for it. Of the 4680 men and women aged 40-59 years, from 17 diverse population samples in Japan, People's Republic of China, UK, and USA, a strong significant inverse education-BP relation was manifest particularly for the 2195 USA participants, independent of ethnicity. With participants stratified by years of education, and assessment of 100+ dietary variables from four 24-h dietary recalls and two 24-h urine collections/person, graded relationships were found between education and intake of many macro- and micronutrients, electrolytes, fibre, and body mass index (BMI). In multiple linear regression analyses with systolic BP (SBP) and diastolic BP (DBP) of individuals the dependent variables (controlled for ethnicity, other possible nondietary confounders), BMI markedly reduced size of education-BP relations, more so for women than for men. Several nutrients considered singly further decreased size of this association by > or =10%: urinary 24-h Na and K excretion, Keys dietary lipid score, vegetable protein, fibre, vitamins C and B6, thiamin, riboflavin, folate, calcium, magnesium, and iron. Combinations of these dietary variables and BMI attenuated the education-SBP inverse coefficient by 54-58%, and the education-DBP inverse coefficient by 59-67%, with over half these effects attributable to specific nutrients (independent of BMI). As a result, the inverse education-BP coefficients ceased to be statistically significant. Multiple specific dietary factors together with body mass largely account for the more adverse BP levels of less educated than more educated Americans. Special efforts to improve eating patterns of less educated strata can contribute importantly to overcoming this and related health disparities in the population.

The Dietary Intervention Study in Children (DISC): dietary assessment methods for 8- to 10-year-olds.

OBJECTIVES: The dietary assessment methods used in the Dietary Intervention Study in Children (DISC) are described and the rationale, validity, and/or general usefulness of each are discussed. DESIGN: DISC is the first multicenter, randomized, clinical trial to study the feasibility and long-term efficacy, safety, and acceptability of a fat-moderately diet in 8- to 10-year-old prepubescent children with moderately elevated plasma low-density lipoprotein cholesterol (LDL-C) levels. Final data collection for the original study (DISC I) occurred December 1, 1993; continued intervention and follow-up (DISC II) will extend beyond 1997. SETTING: Six clinical centers across the country participate in DISC. SUBJECTS: Preadolescent boys and girls with fasting LDL-C levels between the 80th and 98th age-specific and sex-specific percentiles established by the Lipid Research Clinics were eligible for the study. The feasibility phase included 140 children who were then enveloped into the full-scale trial. Baseline dietary data for 652 randomized children in the full-scale trial and 6-month results for the feasibility cohort are reported. INTERVENTIONS: Dietary assessment involved several elements: (a) determining eligibility based on consumption of more than 30% of energy from total fat, (b) monitoring adherence to and adequacy of the intervention diet, (c) evaluating acceptability of the diet in the intervention group, and (d) determining appropriate foods for the intervention diet. Methods are described for each purpose. MAIN OUTCOME MEASURES: LDL-C differences between the two groups and differences in total and saturated fat intakes as calculated from three 24-hour recalls were the primary outcome measures. Six-month dietary differences in the feasibility group are reported. STATISTICAL METHODS: Baseline group means and 6-month differences in dietary intake are reported for the full-scale trial and feasibility study, respectively. RESULTS: Baseline mean intake from three dietary recalls for the intervention (n = 328) and control (n = 324) groups, respectively, were as follows: energy = 1,759 kcal and 1,728 kcal; total energy from fat = 33.3% and 34.0%; total energy from saturated fat = 12.5% and 12.7%; and total dietary cholesterol = 209 mg and 195 mg. After 6 months of intervention, percentage of energy from total fat and saturated fat was reduced by 5.1% (P = .004) and 2.9% (P < .001), respectively, in this feasibility subset (n = 73) of the intervention group. Essentially no change in these parameters occurred in the control group (n = 67), which demonstrates a measurable difference in reporting between groups. APPLICATIONS/CONCLUSIONS: Results illustrate the feasibility of implementing a variety of dietary assessment methods among preadolescent children without relying primarily on parental reports.

Effects on serum lipids of adding instant oats to usual American diets.

This study was designed as a test of the serum lipid response and dietary adaptation to recommended daily inclusion of instant oats in an otherwise regular diet. Hypercholesterolemic adults were randomly assigned to a control or intervention group. Participants in the intervention group were given packages of instant oats and requested to eat two servings per day (approximately two ounces dry weight), substituting the oats for other carbohydrate foods in order to maintain baseline calorie intake and keep weight stable. Serum lipids were measured in blood collected by venipuncture at baseline, four weeks, and eight weeks. Baseline mean total cholesterol (TC) levels were 6.56 mmol/L and 6.39 mmol/L for intervention and control groups, respectively. After eight weeks, mean serum total cholesterol of the intervention group was lower by -0.40 mmol/L, and mean net difference in TC between the two groups was 0.32 mmol/L (95% CI: 0.09, 0.54). Low-density lipoprotein-cholesterol was similarly reduced with mean net difference of 0.25 mmol/L (95% CI: 0.02, 0.48) between the two groups. Mean soluble fiber intake increased along with slight self-imposed reductions in mean total fat, saturated fat, and dietary cholesterol intake in the intervention group. Neither group changed mean body weight. Daily inclusion of two ounces of oats appeared to facilitate reduction of serum total cholesterol and LDL-C in these hyperlipidemic individuals.

Dietary assessment in children using electronic methods: telephones and tape recorders.

Selection of dietary assessment methodology is important in dietary intervention studies. Few studies have reported the relative merits of various assessment methods or the feasibility of electronic methods in pediatric populations. Parent-child dyads performed telephone recalls (no. = 32) and tape recorded dietary records (no. = 33). Traditional recalls were first conducted to familiarize parents and children with the telephone recall procedure, to introduce two-dimensional food models, and to instruct on the use of the tape recorder. Parents monitored and documented as unobtrusively as possible the child's intake on the day before the telephone recall and also on the day of the taped record. Children were called at random to reduce bias. Simple correlation coefficients (r) were calculated for nine nutrients and calories for both methods. For telephone recalls, values ranged from a low of r = .64 for saturated and polyunsaturated fat to r = .85 for cholesterol and r = .93 for iron. Tape-recorded data yielded r = .80 or above, except calories with r = .68 (p less than .001 for all values, 1-tail tests). Mean nutrient values were within expected ranges, e.g., 1,800 kcal +/- 500, with saturated fat about 14% of calories per day. Comparisons between parents and childrens reports of food frequencies and portion sizes revealed the best correlations for beverages, bread-cereals-crackers, meat-fish-poultry, and mixed dishes. We conclude that preadolescent children are able to provide dietary intake data using electronic methods in a manner that compares favorably with their parents' written records.