The impact of birth weight on cardiovascular disease risk in the Women's Health Initiative.

BACKGROUND AND AIMS: Cardiovascular disease (CVD) is among the leading causes of morbidity and mortality worldwide. Traditional risk factors predict 75-80% of an individual's risk of incident CVD. However, the role of early life experiences in future disease risk is gaining attention. The Barker hypothesis proposes fetal origins of adult disease, with consistent evidence demonstrating the deleterious consequences of birth weight outside the normal range. In this study, we investigate the role of birth weight in CVD risk prediction. METHODS AND RESULTS: The Women's Health Initiative (WHI) represents a large national cohort of post-menopausal women with 63,815 participants included in this analysis. Univariable proportional hazards regression analyses evaluated the association of 4 self-reported birth weight categories against 3 CVD outcome definitions, which included indicators of coronary heart disease, ischemic stroke, coronary revascularization, carotid artery disease and peripheral arterial disease. The role of birth weight was also evaluated for prediction of CVD events in the presence of traditional risk factors using 3 existing CVD risk prediction equations: one body mass index (BMI)-based and two laboratory-based models. Low birth weight (LBW) (<6 lbs.) was significantly associated with all CVD outcome definitions in univariable analyses (HR = 1.086, p = 0.009). LBW was a significant covariate in the BMI-based model (HR = 1.128, p < 0.0001) but not in the lipid-based models. CONCLUSION: LBW (<6 lbs.) is independently associated with CVD outcomes in the WHI cohort. This finding supports the role of the prenatal and postnatal environment in contributing to the development of adult chronic disease.

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.

Hormone levels in vegetarian and nonvegetarian teenage girls: potential implications for breast cancer risk.

Between September 1984 and June 1985, a total of 75 adolescent girls, 35 vegetarians residing in a Seventh-Day Adventist school and 40 nonvegetarians residing in a private non-Adventist boarding school, underwent measurement of their plasma hormone levels in the follicular and luteal phase of their menstrual cycles as well as dietary intake measured by 3-day food records, medical history, height, and weight. There were no significant differences between vegetarians and nonvegetarians in average age of the girls, weight, body mass index, age at menarche, years since the onset of menstruation, or percentage of girls with ovulatory cycles. Vegetarian girls had significantly higher levels of log follicular estradiol [2.00 +/- 0.27 (SD) versus 1.85 +/- 0.27 pg/ml, P less than or equal to 0.05] and luteal dehydroepiandrosterone sulfate (DHS) (1.88 +/- 0.71 versus 1.45 +/- 0.80 microgram/ml, P less than or equal to 0.05) than nonvegetarian girls. Follicular DHS was higher in vegetarians than in nonvegetarians (1.72 +/- 0.79 versus 1.45 +/- 0.95 microgram/ml), but the difference was not significant. The differences in follicular and luteal DHS, but not the difference in log estradiol, were significant (P less than or equal to 0.05) after controlling for ovulation, smoking, and alcohol intake with multivariable regression analysis. There were no significant differences in testosterone or in percentage free estradiol levels between vegetarians and nonvegetarians. Smoking was significantly associated with follicular and luteal DHS and with percentage free follicular estradiol, while alcohol use was significantly and inversely associated with percentage free follicular estradiol after controlling for other variables. The implications for breast cancer risk are discussed.

Diet, body size, and plasma lipids-lipoproteins in young adults: differences by race and sex. The Coronary Artery Risk Development in Young Adults (CARDIA) study.

The Coronary Artery Risk Development in Young Adults (CARDIA) study completed baseline dietary assessment, measurement of body mass index, and lipid and lipoprotein analyses on 5,111 participants. CARDIA includes black and white men and women between 18 and 30 years of age at baseline (1985-1986), recruited in Birmingham, Alabama, Chicago, Illinois, Minneapolis, Minnesota, and Oakland, California. Diet was assessed by a detailed interviewer-administered diet history that measured the usual eating pattern over the past month. Possible sex, race, age, and educational differences in diet, body size, and lipids-lipoproteins were explored. Nutrient analyses indicate that the Keys score, a measure of dietary fat composition, is significantly correlated with plasma cholesterol in older (aged 25-30 years) white men (r = 0.12, p less than 0.01) and older white women (r = 0.12, p less than 0.001). In multiple linear regression analyses, body mass index was positively and significantly associated with total cholesterol and low density lipoprotein cholesterol and inversely associated with high density lipoprotein cholesterol across all race-sex groups. The Keys score was significantly associated with total cholesterol and low density lipoprotein cholesterol in white men and women. Education was associated with high density lipoprotein cholesterol in black and white women and white men. In these young adults, dietary fat intake and body mass index were related to blood lipids in certain subgroups. In black and white men and black women, blood cholesterol increased with age across race-sex groups independently of these covariates. In view of the many factors affecting plasma cholesterol and the limitations of the dietary history method, these cross-sectional data are useful in characterizing diet and lipid differences. There appears to be general disparity between recommended dietary intake of total fat, saturated fat, and other nutrients and actual dietary intake in young adults, regardless of age and educational level.

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.

Controlling cholesterol levels through diet.

High blood cholesterol levels are a major risk factor for coronary artery disease. Recent studies have shown that a cholesterol-lowering diet has a principal role in reducing coronary events in humans. A diet low in saturated fat and cholesterol is recommended for patients with a cholesterol level of more than 240 mg/dl or a level of between 200 and 239 mg/dl plus other risk factors. Measurement of low-density lipoprotein and high-density lipoprotein cholesterol levels provides a baseline value by which to gauge progress. Periodic assessment by the physician will give an indication of patient compliance. For patients who do not achieve desired goals within six months, drug therapy may be necessary.

A long-term nutrition intervention experience: lipid responses and dietary adherence patterns in the Multiple Risk Factor Intervention Trial.

Nutrition counselors in the Multiple Risk Factor Intervention Trial (MRFIT) were able to help middle-aged men who were at high risk for coronary heart disease change their dietary habits, maintain those changes over time, and decrease their serum cholesterol levels. Most of a 7.5% mean serum cholesterol reduction achieved after 6 years of nutrition intervention occurred during the first year of the trial and was thereafter sustained. Total cholesterol and low-density lipoprotein cholesterol fraction decreases indicated improvement in terms of coronary heart disease risk. The food record rating, a numerical, semi-objective adherence technique that assesses a 3-day food record with respect to lipid-lowering potential, was used throughout the trial to measure adherence to recommended food patterns. Participants with lower food record rating scores, which indicate better adherence, demonstrated greater reductions in serum total cholesterol, plasma total cholesterol, and low-density lipoprotein fraction cholesterol determinations on a group basis. Subjective evaluations of the suitability of home and working environments, evidence of deviation from the MRFIT food patterns, and overall nutrition program motivation also showed that as ratings in each category became more favorable, lower food record rating scores and greater blood lipid reductions were consistently observed. The subgroup of participants who were non-smokers and not hypertensive demonstrated greater lipid responses and better dietary adherence. Continued smoking and antihypertensive medications appeared to adversely influence dietary adherence and/or lipid reductions. The MRFIT experience, however, demonstrated for the first time that dietary changes and blood lipid reductions can be achieved after the initial intervention effect, despite a continued emphasis on high blood pressure management and smoking cessation.

Increasing the use of meatless meals: a nutrition intervention substudy in the Multiple Risk Factor Intervention Trial (MRFIT).

Forty-seven participants from six MRFIT clinical centers were involved in a 3-month intensive dietary intervention program to determine the feasibility of increasing the use of meatless meals. The substudy was conducted late in the trial, and many dietary changes had already been made. The purpose, therefore, was to initiate ways to continue the maintenance of achieved serum cholesterol reductions and possibly effect additional decreases. The program consisted of an introductory session and three follow-up visits. Preplanning, contracting, self-monitoring, regular follow-up, and homemaker involvement were among techniques used to help participants incorporate meatless meals into routine dietary practices. Data collection included scores from a knowledge test administered at the introductory and final visits, number of meatless meals consumed per week as contracted at the first three visits and as reported at the last three visits, and serum cholesterol and weight determinations made at each visit. Knowledge related to meatless meal concepts, such as complementary proteins, appeared to improve as the majority of substudy participants scored higher on the post-test than on the pretest. Over the substudy duration, the mean number of contracted and reported weekly meatless meals in addition to breakfast was approximately four and five, respectively. Mean serum cholesterol drop was 2.6%, and mean weight loss was about 3 lb over the 3-month period. The approach was one of the intervention techniques used to maintain serum cholesterol reductions on a long-term basis, which has not been achieved in any other clinical trial with similar objectives. The described meatless meals program may prove useful to dietetic practitioners who counsel individuals in fat-modified food patterns.

Serum lipid response to oat product intake with a fat-modified diet.

Healthy adult volunteers (no. = 208), men and women aged 30 to 65 years, participated in a 12-week study on dietary fat modification plus oat product ingestion (60 gm/day) to test whether moderate daily intake of oat bran and oatmeal enhanced serum lipid response. During weeks 0 to 6, all participants followed the American Heart Association fat-modified eating style. At 6 weeks, participants were randomly assigned to one of three groups. All participants continued to follow the fat-modified eating pattern; groups 1 and 2 were asked during weeks 7 to 12 to consume two servings of either oat bran or oatmeal per day, for a total of 60 gm/day isocalorically substituted for other carbohydrates. Group 3 ingested no oat products. At baseline, the group mean cholesterol level was 208.4 mg/dl. After 6 weeks of dietary fat intervention, the level was 197.6--a fall of 10.8 mg/dl (5.2%). At 12 weeks, the mean serum cholesterol level fell further, by 5.6, 6.5, and 1.2 mg/dl for groups 1, 2, and 3, respectively. Group mean weight loss was small--1.9 lb during the first 6 weeks and 0.6 to 0.8 for the three groups during weeks 7 to 12. Reported oat product ingestion was 39 and 35 gm per person per day, respectively, for groups 1 and 2 (2.2 and 1.4 servings per person per day, respectively). Dietary fat composition remained similar among the three groups during weeks 7 to 12. Pooled results indicated that the addition of oat products at a moderate and practical level enhanced serum lipid response (p less than .05) to a fat-modified eating pattern among free-living adults.