Reproductive history and osteoarthritis in the Women's Health Initiative

Objective: To investigate the relationship between self-reported osteoarthritis (OA) and reproductive factors in the Women's Health Initiative (WHI). Method: We used multivariable logistic regression to study the association of self-reported OA and reproductive factors in the WHI Observational Study and Clinical Trial cohorts of 145 965 postmenopausal women, in a retrospective cross-sectional format. Results: In our cohort, we observed no clinically significant associations between reproductive factors and OA given small effect sizes. The following factors were associated with statistically significant increased likelihood of developing OA: younger age at menarche (p < 0.001), history of hysterectomy [adjusted odds ratio (aOR) 1.013, 95% confidence interval (CI) 1.004-1.022, p = 0.04 vs no hysterectomy], history of unilateral oophorectomy (aOR 1.015, 95% CI 1.004-1.026, p < 0.01 vs no oophorectomy), parity (aOR 1.017, 95% CI 1.009-1.026, p < 0.001), ever use of oral contraceptives (aOR 1.008, 95% CI 1.001-1.016, p < 0.01 vs never use), and current use of hormonal therapy (reference current users, aOR 0.951, 95% CI 0.943-0.959 for never users; aOR 0.981, 95% CI 0.972-0.989 for past users; global p < 0.001). Age at menopause, first birth, and pregnancy were not associated with OA. Among parous women, no clear pattern was observed with number of pregnancies, births, or duration of breastfeeding in relation to OA. Conclusion: Our study showed that reproductive factors did not have significant clinical associations with OA after controlling for confounders. This may be due to complex hormonal effects. Additional investigation is warranted in prospective cohort studies. The Women's Health Initiative is registered under ClinicalTrials.gov. Trial registration ID: NCT00000611.

Long chain fatty acids and related pro-inflammatory, specialized pro-resolving lipid mediators and their intermediates in preterm human milk during the first month of lactation

This study aimed to measure longitudinal quantities of the long chain fatty acids, their biologically active terminal metabolites and related intermediates (also called oxylipins) in preterm human milk expressed during the first month of lactation. In a prospective cohort, breast milk was collected throughout the first month of lactation in 30 women who delivered preterm infants. Eighteen bioactive lipids and their intermediates were quantified via solid phase extraction and LC-MS/MS. Analysis by GC-FID quantified the fatty acid precursors. Arachidonic acid (ARA) and docosahexaenoic acid (DHA) milk concentrations significantly declined throughout the first month. Oxylipin concentrations did not change during lactation. Positive associations existed between ARA and thromboxane B2, eicosapentaenoic acid and 18-hydroxyeicosapentaenoic acid, and between DHA and PDX and 14- and 17-hydroxydocosahexaenoic acids. DHA concentrations were 1.5 times higher and 14-HDHA was 1.7 times higher in milk from women taking DHA supplements. This investigation showed conditionally essential fatty acids, ARA and DHA, decreased in preterm milk, suggesting a need to supplement their intake for the breast milk-fed preterm infant. Positive associations between parent fatty acids, bioactive lipids and intermediates, as well as sensitivity of milk to maternal fatty acid intake, support consideration of a comprehensive approach to providing fatty acids for preterm infants through both maternal and infant supplementation.

Circadian timing and alignment in healthy adults: associations with BMI, body fat, caloric intake and physical activity

Introduction

Disruption of circadian rhythms is one of the proposed mechanisms linking late sleep timing to obesity risk but few studies have evaluated biological markers outside of the laboratory. The goal of this study was to determine the relationship between the timing and alignment of melatonin and sleep onset (phase angle) with BMI, body fat and obesity related behaviors. We hypothesized that circadian alignment (relationship of melatonin to sleep timing) rather than circadian (melatonin) timing would be associated with higher BMI, body fat, dietary intake and lower physical activity.

Subjects/Methods

Adults with sleep duration ≥6.5 hours completed 7 days of wrist actigraphy, food diaries and SenseWear arm band monitoring. Circadian timing, measured by dim light melatonin onset (DLMO) was measured in the clinical research unit. Circadian alignment was calculated as the duration between dim light melatonin onset and average sleep onset time in the prior week (phase angle). Body fat was evaluated using dual-energy absorptiometry (DXA). Data were analyzed using bivariate correlations and multivariable regression analyses controlling for age, sex, sleep duration and evening light exposure.

Results

Participants included 97 adults (61 F, age 26.8 ± 7.3 years) with average sleep duration 443.7 (SD= 50.4) minutes. Average phase angle was 2.2 hours (SD= 1.5). Circadian alignment was associated with circadian timing (p<0.001) and sleep duration (p=.005). In multivariable analyses, later circadian timing was associated with lower BMI (p=.04). Among males only, circadian alignment was associated with percent body fat (p=.02) and higher android/gynoid fat ratio (p=0.04). Circadian alignment was associated with caloric intake (p=0.049) carbohydrate intake (p=0.04) and meal frequency (p=0.03) among both males and females.

Conclusion

Circadian timing and alignment were not associated with increased BMI or body fat, among healthy adults with ≥6.5 hours of sleep, but circadian alignment was associated with dietary intake. There may be sex differences in the relationship between circadian alignment and body fat.

Adolescent Endogenous Sex Hormones and Breast Density in Early Adulthood

During adolescence the breasts undergo rapid growth and development under the influence of sex hormones. Although the hormonal etiology of breast cancer is hypothesized, it remains unknown whether adolescent sex hormones are associated with adult breast density, which is a strong risk factor for breast cancer. METHODS: Percentage of dense breast volume (%DBV) was measured in 2006 by magnetic resonance imaging in 177 women aged 25–29 years who participated in the Dietary Intervention Study in Children from 1988–1997 and had sex hormones and sex hormone binding globulin (SHBG) measured in serum collected on 1–4 occasions between 8 and 17 years of age. Multivariable linear mixed-effect regression models were used to evaluate the associations of adolescent sex hormones and SHBG with %DBV. RESULTS: Dehydroepiandrosterone sulfate (DHEAS) and SHBG measured in premenarche serum samples were significantly positively associated with %DBV (all Ptrend ≤ 0.03) but not when measured in postmenarche samples (all Ptrend ≥ 0.42). The multivariable geometric mean of %DBV across quartiles of premenarcheal DHEAS and SHBG increased from 16.7% to 22.1% and from 14.1% to 24.3%, respectively. Estrogens, progesterone, androstenedione, and testosterone were not associated with %DBV pre- or post-menarche (all Ptrend ≥ 0.16). CONCLUSIONS: Our results suggest that higher DHEAS and SHBG levels during adolescence, particularly before the onset of menarche, are associated with higher%DBV in young women. Whether this association translates into an increased risk of breast cancer later in life is currently unknown.

Relation of raw and cooked vegetable consumption to blood pressure: the INTERMAP Study

Inverse associations have been reported of overall vegetable intake to blood pressure (BP); whether such relations prevail for both raw and cooked vegetables has not been examined. Here we report cross-sectional associations of vegetable intakes with BP for 2195 Americans ages 40-59 in the International Study of Macro/Micronutrients and Blood Pressure (INTERMAP) using four standardized multi-pass 24-h dietary recalls and eight BP measurements. Relations to BP of raw and cooked vegetables consumption, and main individual constituents were assessed by multiple linear regression. Intakes of both total raw and total cooked vegetables considered separately were inversely related to BP in multivariate-adjusted models. Estimated average systolic BP differences associated with two s.d. differences in raw vegetable intake (68 g per 1000 kcal) and cooked vegetable intake (92 g per 1000 kcal) were -1.9 mm Hg (95% confidence interval (CI): -3.1, -0.8; P=0.001) and -1.3 mm Hg (95% CI: -2.5, -0.2; P=0.03) without body mass index (BMI) in the full model; -1.3 mm Hg (95% CI: -2.4, -0.2; P=0.02) and -0.9 mm Hg (95% CI: -2.0, 0.2; P=0.1) with additional adjustment for BMI. Among commonly consumed individual raw vegetables, tomatoes, carrots, and scallions related significantly inversely to BP. Among commonly eaten cooked vegetables, tomatoes, peas, celery, and scallions related significantly inversely to BP.

Diet quality and markers of endothelial function: the CARDIA study

BACKGROUND AND AIM

Dietary patterns are associated cross-sectionally with cellular adhesion molecules (CAMs). We studied prospective associations of three dietary patterns with CAMs.

METHODS AND RESULTS

In the Coronary Artery Risk Development in Young Adults (CARDIA) study, diet was assessed at years 0 (1985-86) and 7 (1992-93) examinations. Four circulating CAMs (E-selectin, P-selectin, soluble intercellular adhesion molecule 1 (sICAM-1), and vascular cellular adhesion molecule (VCAM)) were assayed at years 7 and 15 (2000-01). We created one index score "A Priori Diet Quality Score" and derived dietary patterns using principal components analysis (PCA). Multivariable linear regression models predicted year 15 CAMs from averaged (year 0/7) dietary patterns. The A Priori Diet Quality Score rated 46 food groups beneficial, neutral or adverse based on hypothesized health effects. We derived two PCA dietary patterns: "fruit and vegetables (FV)" (high intakes of fruit, vegetables, and whole grains) and "meat" (high intakes of red meat, refined grain, and butter). All dietary patterns were related to E-selectin and sICAM-1. P-selectin was not related to the FV dietary pattern. VCAM was only related to the A Priori Diet Quality Score. Strongest associations were for the meat dietary pattern with E-selectin (effect size 28% of an SD (+3.9/13.7 ng/mL)) and P-selectin (effect size 37% of an SD (+4.1/11.2 ng/mL)) and the A Priori Diet Quality Score with sICAM-1 (effect size 34% of an SD (-15.1/44.7 ng/mL)) and VCAM (effect size of 26% of an SD (-45.1/170.3 ng/mL)).

CONCLUSION

This prospective analysis suggests that dietary patterns are associated with CAMs.

Health risks and benefits from calcium and vitamin D supplementation: Women's Health Initiative clinical trial and cohort study

SUMMARY

The Women's Health Initiative (WHI) double-blind, placebo-controlled clinical trial randomly assigned 36,282 postmenopausal women in the U.S. to 1,000 mg elemental calcium carbonate plus 400 IU of vitamin D(3) daily or placebo, with average intervention period of 7.0 years. The trial was designed to test whether calcium plus vitamin D supplementation in a population in which the use of these supplements was widespread would reduce hip fracture, and secondarily, total fracture and colorectal cancer.

INTRODUCTION

This study further examines the health benefits and risks of calcium and vitamin D supplementation using WHI data, with emphasis on fractures, cardiovascular disease, cancer, and total mortality.

METHODS

WHI calcium and vitamin D randomized clinical trial (CT) data through the end of the intervention period were further analyzed with emphasis on treatment effects in relation to duration of supplementation, and these data were contrasted and combined with corresponding data from the WHI prospective observational study (OS).

RESULTS

Among women not taking personal calcium or vitamin D supplements at baseline, the hazard ratio [HR] for hip fracture occurrence in the CT following 5 or more years of calcium and vitamin D supplementation versus placebo was 0.62 (95 % confidence interval (CI), 0.38-1.00). In combined analyses of CT and OS data, the corresponding HR was 0.65 (95 % CI, 0.44-0.98). Supplementation effects were not apparent on the risks of myocardial infarction, coronary heart disease, total heart disease, stroke, overall cardiovascular disease, colorectal cancer, or total mortality, while evidence for a reduction in breast cancer risk and total invasive cancer risk among calcium plus vitamin D users was only suggestive.

CONCLUSION

Though based primarily on a subset analysis, long-term use of calcium and vitamin D appears to confer a reduction that may be substantial in the risk of hip fracture among postmenopausal women. Other health benefits and risks of supplementation at doses considered, including an elevation in urinary tract stone formation, appear to be modest and approximately balanced.

Effect of long term low-fat dietary intervention on change in hemostatic factors: results from the Women's Health Initiative

Low-fat diet may play a role in prevention of cardiovascular disease (CVD) by altering the levels of hemostatic factors. There are yet limited data on the effects of low-fat diet on the circulating levels of these factors and existing studies are limited by small sample size and short duration of follow-up. We conducted an analysis in a subset of women (active arm = 723; control arm = 1036) within the Women's Health Initiative Dietary Modification Trial to investigate the long term effect of a low-fat diet on circulating levels of fibrinogen, factor VII concentration and factor VII activity among postmenopausal women aged 50-79 years. Using linear mixed effects model with random intercept and data from three follow-up visits (years 1, 3 and 6) we evaluated the change in each factor over time. Overall, the changes in these factors were small (less than 5%) in both the arms of the trials at the end of intervention and there was no significant difference in mean change between the two arms. Our results indicate that the low-fat dietary intervention was not associated with significant changes in hemostatic factors among postmenopausal women.

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.

Oats and soy in lipid-lowering diets for women with hypercholesterolemia: is there synergy?

OBJECTIVES

To study possible synergistic effects of oats and soy on reducing total and low-density lipoprotein cholesterol (LDL-C) concentrations in human beings and the efficacy and feasibility of including these adjustments to a National Cholesterol Education Program Step I diet. SUBJECT/SETTING: One hundred twenty-seven postmenopausal women with moderate hypercholesterolemia were recruited from a large Midwestern workforce and senior centers in the surrounding community. Intervention and clinical visits were conducted in these same facilities.

DESIGN

After a 3-week lead-in period on the Step I diet, participants were randomly assigned to 1 of 4 dietary treatments for an additional 6 weeks: an oats/milk group, a wheat/soy group, an oats/soy group, and a wheat/milk group. Clinical measurements included blood draws, body weight and height, blood pressure, and medical history data. Three-day food records were collected at baseline and Weeks 3 and 9 of the intervention. Randomization was stratified based on the status of hormone replacement therapy and was blocked with sizes 4 or 8 for group assignment.

RESULTS

After 3 weeks on the Step I diet, total cholesterol, LDL-C, and triglyceride levels; total fat and saturated fat intake, dietary cholesterol intake, Keys score, and body mass index were all reduced. Following an additional 6 weeks on the Step I diet plus intervention, total cholesterol and LDL-C were further reduced for both the oats/soy group and oats/milk group. There were no significant further changes in total cholesterol, LDL-C, or high-density lipoprotein cholesterol levels in the wheat/soy and wheat/milk groups. Body mass index remained stable in all groups from Week 3 to Week 9.

APPLICATIONS

Nonpharmacologic dietary interventions like the Step I diet are feasible in a community setting and can produce rapid and significant lipid-lowering benefits. Daily consumption of 2 servings of oats can contribute to further lipid alterations in this population although soy intake at this dose may not. Palatability and convenience are important considerations in achieving dietary adherence.

Translation of nutritional sciences into medical education: the Nutrition Academic Award Program

For the past 40 y the scientific community has decried the inadequacy of the training of physicians and other health professionals in the subject of human nutrition. In 1997 the National Heart, Lung, and Blood Institute developed the Nutrition Academic Award (NAA) Program, an initiative to improve nutrition training across a network of US medical schools. The purpose of this funding, which began in 1998, is to support the development and enhancement of nutrition curricula for medical students, residents, and practicing physicians to learn principles and practice skills in nutrition. The NAA recipients developed the Nutrition Curricular Guide for Training Physicians, a plan to incorporate clinical guidelines into physician practice skills, create educational and assessment practice tools, and evaluate curricula, materials, and teaching tools. Dissemination of NAA activities and materials will be facilitated by a national website, presentations and publications, and consultants and advisors from the NAA nutrition education programs. The NAA Program constitutes a major new effort to enhance nutrition knowledge and skills among health care providers and to effectively apply the science of human nutrition to clinical medicine. This article describes the purpose and aims of the NAA Program, the organizational structure of the network of recipients, a profile of the recipients and individual programs at 21 medical schools, the various strategies to overcome barriers in training physicians in human nutrition, and collaborative and dissemination efforts.

Development of a measure of attitude toward nutrition in patient care

BACKGROUND

Development of reliable measures of medical student and resident attitudes about nutrition in patient care is needed before the effects of educational interventions or clinical experience can be gauged. This report describes the systematic development of a measure of attitude toward nutrition in patient care. It presents evidence about scale reliability and the absence of response bias that endorses the trustworthiness of data from the measure.

METHODS

An eight-step attitude scale development procedure was used to create the Nutrition In Patient care Survey (NIPS). Data from five samples of first- and second-year medical students and first-year medical residents were subjected to factor analysis (PA2, varimax rotation), reliability analyses, and statistical analyses to test for demographic bias in the attitude data.

RESULTS

A 45-item attitude measure was developed that contains five subscales derived from the factor analysis: (1) nutrition in routine care (NRC, 8 items); (2) clinical behavior (CB, 20 items); (3) physician-patient relationship (PPR, 8 items); (4) patient behavior/motivation (PBM, 3 items); and (5) physician efficacy (PE, 6 items). Each subscale yields reliable data in terms of internal consistency (alpha coefficients) and stability (test-retest reliability). Medical student and resident demographic variables have negligible influence on attitude scores.

DISCUSSION

The NIPS subscales yield reliable data that can be used to assess outcomes in evaluation research on educational or clinical interventions or to predict patient care practices. Systematic attitude scale development increases the likelihood that the resulting measures will produce useful, trustworthy data.

Saliva as a medium for investigating intra- and interindividual differences in sex hormone levels in premenopausal women

Repeated measurement of ovarian steroids in saliva could provide an advantage in studies estimating long-term sex steroid exposure in premenopausal women, by reducing the measurement error associated with collection of serum or urine samples. We previously reported on characteristics of ultrasensitive RIAs adapted for extraction-free measurement of estradiol (E2) and progesterone (PG) in saliva. The purpose of the present study was to evaluate the consistency of E2 and PG levels in saliva in the same women across menstrual cycles, and to compare this with the variation observed between women. We also evaluated the effect of altering the number of consecutive daily samples considered and the method for locating a particular cycle day in relation to ovulation (day 0). Study participants included 12 healthy women who provided daily saliva samples for two consecutive, ovulatory menstrual cycles. A single midluteal serum sample was collected 7-8 days after detection of a luteinizing hormone (LH) peak in urine. We plotted individual cycle profiles and computed intraclass correlation coefficients (ICC) for various definitions of peak and cumulative daily hormone level. For peak PG, determined as the maximal running 3-day mean, ICC was 0.68. For cumulative PG, based on 8 consecutive cycle days (+2 to +9), ICCs were 0.72-0.76 when reverse dating LH peak or rise in salivary PG determined day 0. For E2, ICCs ranged from 0.74 to 0.79 by various dating methods for the 5 preovulatory days (-4-0), and from 0.85 to 0.92 for the 15 days about the center of the cycle (-6 to +8). With exclusion of just the first 5 days of the cycle, the ICC for E2 was 0.91. For both E2 and PG, selection of 5 or 7 days for the estimation of the midluteal mean level provided separation of within and between subject variance that was comparable with a LH-timed serum sample. These results indicate that daily saliva samples can be combined to clarify the interindividual differences in E2 and PG levels in premenopausal women, and that these interindividual differences may be greater than previously imagined.

Efficacy and safety of lowering dietary intake of total fat, saturated fat, and cholesterol in children with elevated LDL cholesterol: the Dietary Intervention Study in Children

BACKGROUND

Few studies have shown the efficacy and safety of lower-fat diets in children.

OBJECTIVE

Our objective was to assess the efficacy and safety of lowering dietary intake of total fat, saturated fat, and cholesterol to decrease LDL-cholesterol concentrations in children.

DESIGN

A 6-center, randomized controlled clinical trial was carried out in 663 children aged 8-10 y with LDL-cholesterol concentrations greater than the 80th and less than the 98th percentiles for age and sex. The children were randomly assigned to either an intervention group or a usual care group. Behavioral intervention promoted adherence to a diet providing 28% of energy from total fat, <8% from saturated fat, </=9% from polyunsaturated fat, and <0.018 mg cholesterol*kJ(-)(1)*d(-)(1) (not to exceed 150 mg/d). The primary efficacy measure was mean LDL cholesterol and the safety measures were mean height and serum ferritin concentration at 3 y.

RESULTS

At 3 y, dietary total fat, saturated fat, and cholesterol were lower in the intervention group than in the usual care group (all P: < 0. 001). LDL cholesterol decreased in the intervention and usual care groups by 0.40 mmol/L (15.4 mg/dL) and 0.31 mmol/L (11.9 mg/dL), respectively. With adjustment for baseline concentration, sex, and missing data, the mean difference between groups was -0.08 mmol/L (95% CI: -0.15, -0.01), or -3.23 mg/dL (95% CI: -5.6, -0.5) (P: = 0. 016). There were no significant differences between groups in adjusted mean height or serum ferritin.

CONCLUSION

Dietary changes are effective in achieving modest lowering of LDL cholesterol over 3 y while maintaining adequate growth, iron stores, nutritional adequacy, and psychological well-being during the critical growth period of adolescence.

Maintenance of dietary behavior change

Reducing dietary fat, saturated fat, and sodium and increasing intakes of dietary fiber and fruits and vegetables are important for cardiopulmonary risk reduction. Behaviorally, these dietary changes are very challenging, and in different ways. Fewer than half of U.S. adults have diets meeting recommended intakes of these constituents, and many do not see a need to align their diets with recommendations. Various nutrition education and behavioral counseling approaches have been shown to facilitate changes in fat, fiber, sodium, and fruits and vegetables, but primarily in research settings and among the highly motivated. Practice-based and interdisciplinary studies are needed to refine strategies to effect long-term dietary changes, to differentiate behavioral issues for changes involving additions versus deletions from the diet, and to elucidate the roles of sensory, psychosocial, and contextual factors in adoption and maintenance.

Dietary fiber, weight gain, and cardiovascular disease risk factors in young adults

CONTEXT

Dietary composition may affect insulin secretion, and high insulin levels, in turn, may increase the risk for cardiovascular disease (CVD).

OBJECTIVE

To examine the role of fiber consumption and its association with insulin levels, weight gain, and other CVD risk factors compared with other major dietary components.

DESIGN AND SETTING

The Coronary Artery Risk Development in Young Adults (CARDIA) Study, a multicenter population-based cohort study of the change in CVD risk factors over 10 years (1985-1986 to 1995-1996) in Birmingham, Ala; Chicago, III; Minneapolis, Minn; and Oakland, Calif.

PARTICIPANTS

A total of 2909 healthy black and white adults, 18 to 30 years of age at enrollment.

MAIN OUTCOME MEASURES

Body weight, insulin levels, and other CVD risk factors at year 10, adjusted for baseline values.

RESULTS

After adjustment for potential confounding factors, dietary fiber showed linear associations from lowest to highest quintiles of intake with the following: body weight (whites: 174.8-166.7 lb [78.3-75.0 kg], P<.001; blacks: 185.6-177.6 lb [83.5-79.9 kg], P = .001), waist-to-hip ratio (whites: 0.813-0.801, P = .004; blacks: 0.809-0.799, P = .05), fasting insulin adjusted for body mass index (whites: 77.8-72.2 pmol/L [11.2-10.4 microU/mL], P = .007; blacks: 92.4-82.6 pmol/L [13.3-11.9 microU/mL], P = .01) and 2-hour postglucose insulin adjusted for body mass index (whites: 261.1-234.7 pmol/L [37.6-33.8 microU/mL], P = .03; blacks: 370.2-259.7 pmol/L [53.3-37.4 microU/mL], P<.001). Fiber was also associated with blood pressure and levels of triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and fibrinogen; these associations were substantially attenuated by adjustment for fasting insulin level. In comparison with fiber, intake of fat, carbohydrate, and protein had inconsistent or weak associations with all CVD risk factors.

CONCLUSIONS

Fiber consumption predicted insulin levels, weight gain, and other CVD risk factors more strongly than did total or saturated fat consumption. High-fiber diets may protect against obesity and CVD by lowering insulin levels.

A brief motivational intervention to improve dietary adherence in adolescents. The Dietary Intervention Study in Children (DISC) Research Group

Motivational interviewing offers health care professionals a potentially effective strategy for increasing a patient's readiness to change health behaviors. Recently, elements of motivational interviewing and the stages of change model have been simplified and adapted for use with patients in brief clinical encounters. This paper describes in detail a brief motivational intervention model to improve and renew dietary adherence with adolescents in the Dietary Intervention Study in Children (DISC). DISC is a randomized, multi-center clinical trial assessing the efficacy and safety of lowering dietary fat to decrease low-density lipoprotein cholesterol in high-risk children. In the first 3 years of follow-up covering ages 8-13, intervention participants (n = 334) were exposed to a family-based group intervention approach to change dietary choices. To address adherence and retention obstacles as participants moved into adolescence (age 13-17), an individual-level motivational intervention was implemented. The DISC motivational intervention integrates several intervention models: stages of change, motivational interviewing, brief negotiation and behavioral self-management. A preliminary test of the intervention model suggests that it was acceptable to the participants, popular with interventionists and appeared to be an age-appropriate shift from a family-based intervention model.

Relationship between changes in dietary sucrose and high density lipoprotein cholesterol: the CARDIA study. Coronary Artery Risk Development in Young Adults

PURPOSE

Cross-sectional data from several observational studies have suggested that dietary sucrose may be inversely associated with high density lipoprotein cholesterol (HDL-C). This study examined associations between energy from dietary sucrose and HDL-C at baseline, year 7 and longitudinally (year 7 minus baseline) in a cohort of young black and white men and women from the Coronary Artery Risk Development in Young Adults (CARDIA) study.

METHODS

The sample included 4734 black men, black women, white men and white women, ages 18-30 years, in 1985-86 (baseline); 3513 at year 7; and 3335 for longitudinal analyses. Multivariate analyses was used with adjustment for age, BMI, cigarettes smoked per day, physical activity score, and alcohol intake.

RESULTS

Multivariate analyses indicated that energy intake from sucrose was inversely associated with HDL-C for each race-gender group at baseline, year 7, and longitudinally from baseline to year 7. This association was significant at baseline for black men, and white men and women (p < 0.01); at year 7 for white men and black women (p < 0.01), and longitudinally for white men, white women, and black women (p < 0.05).

CONCLUSIONS

The consistent inverse associations between energy from dietary sucrose and HDL-C observed in both cross-sectional and longitudinal analyses, and in different race and gender groups in CARDIA suggest that lowering dietary sucrose intake may be beneficial for those who may have low HDL-C.

Diet and cardiovascular disease prevention: what works?

Diet is routinely recommended as the primary strategy for the prevention and treatment of high blood cholesterol. The National Cholesterol Education Program (NCEP), the American Heart Association (AHA), and a host of other health and medical organizations have advocated a diet low in total and saturated fat and cholesterol for reducing risk of cardiovascular disease. What is the evidence supporting these guidelines and the expected efficacy of dietary treatment? There is growing awareness that despite well-documented rationale for the dietary approach, many eligible patients are not routinely prescribed dietary treatment, and among those who are, there is limited response. What are the obstacles in implementing effective dietary intervention for prevention of cardiovascular disease? What are both the theoretical and practical limitations to achieving long-term adherence to diet and what strategies have been shown to be most effective? A review of the data surrounding these diet-lipid relationships is presented along with recently tested and promising behavioral approaches to facilitating patient adherence.

Dietary fat consumption and health

Dietary Guidelines have emerged over the past 30 years recommending that Americans limit their consumption of total fat and saturated fat as one way to reduce the risk of a range of chronic diseases. However, a low-fat diet is not a no-fat diet. Dietary fat clearly serves a number of essential functions. For example, maternal energy deficiency, possible exacerbated by very low-fat intakes (< 15% of energy), is one key determinant in the etiology of low birth weight. The debate continues over recommendations for limiting total fat and saturated fatty acid intake in children. Recent evidence indicates that diets with adequate energy providing less than 30% of energy from fat are sufficient to promote normal growth and normal sexual maturation. More attention needs to be devoted to the effect of dietary fat reduction on the nutrient density of children's diets. The association between dietary fat and CHD has been extensively studied. Diets high in saturated fatty acids and trans fatty acids increase LDL cholesterol levels, and in turn, the risk of heart disease. The relationship between high-carbohydrate/low-fat diets and CHD is more ambiguous because high-carbohydrate diets induce dyslipidemia in certain individuals. Obesity among adults and children is now of epidemic proportions in the United States. High-fat diets leading to excessive energy intakes are strongly linked to the increasing obesity in the United States. However, the prevalence of obesity has increased during the same time period that dietary fat intake (both in absolute terms and as a percentage of total dietary energy) has decreased. These trends suggest that a concomitant decrease in total dietary energy and modifications of other lifestyle factors, such as physical activity, also need to be emphasized. Obesity is also an independent risk factor for the development of diabetes. The current availability of fat-modified foods offers the potential for dietary fat reduction and treatment of the comorbidities associated with diabetes. However, to date, few studies have documented the effectiveness of fat-modified foods as part of a weight loss regimen or in reduction in CHD risks among individuals with diabetes mellitus. The association between total dietary fat and cancer is still under debate. While there is some evidence demonstrating associations between dietary fat intake and cancers of the breast, prostate, and colon, there are serious methodologic issues, including the difficulty in differentiating the effects of dietary fat independent of total energy intake. Reported total fat and saturated fatty acid intakes as a percentage of total energy have been declining over the past 30 years in the United States. Despite this encouraging trend, the majority of individuals--regardless of age--do not report consuming a diet that meets the levels of fat and saturated fatty acids recommended by the Dietary Guidelines for Americans. On a relative basis, saturated fat intake has gone down less than has total fat intake. Individuals of all ages who report consuming a diet with < or = 30% of energy from fat consistently have lower energy intakes. Given the increasing rates of obesity in the United States at an earlier and earlier age, dietary fat reduction may be an effective part of an overall strategy to balance energy consumption with energy needs. In each of the age/gender groups reporting consumption of < or = 30% of energy from fat and less than 10% of energy from saturated fatty acids, fat-modified foods play a more important role in their diets than for people who are consuming higher levels of fat and saturated fat. The data are clear than fat-modified foods make a more significant contribution to diets of consumers with low-fat intakes. While one cannot argue cause and effect from the results presented, the patterns of fat-modified foods/low-fat intakes are consistent. The focus on overall diet quality is often lost in the national obsession with lowering fat inta

Maternal acceptability of a dietary intervention designed to lower children's intake of saturated fat and cholesterol: the Dietary Intervention Study in Children (DISC)

OBJECTIVE

This report examined the acceptability to mothers of a dietary educational and behavioral intervention for preadolescent children with elevated levels of serum low-density lipoprotein cholesterol (LDL-C) who were enrolled in the Dietary Intervention Study in Children (DISC).

DESIGN

DISC is a randomized, controlled clinical trial. Subjects were randomly assigned to either an intervention or usual-care (control) group.

SUBJECTS/SETTING

To be eligible for the study, participants were required to have the average of 2 fasting LDL-C values fall between the 80th and 98th sex-specific percentiles. Three hundred thirty-four 8-to 10-year-old children and their families were randomly assigned to an intervention group, and 329 were assigned to a usual-care (control) group. This study examined data from 232 subjects in the intervention group. Data were collected at 6 intervention sites around the United States.

INTERVENTION

Those assigned to the intervention group participated in a multidisciplinary dietary intervention that included a series of group and individual sessions over a 3-year period. Children and their caretakers were taught to follow a nutritionally adequate diet that was low in total fat, saturated fat, and cholesterol and high in polyunsaturated fat.

MAIN OUTCOME MEASURES

Three nonconsecutive 24-hour diet recalls were collected at baseline and at 1 year by trained and certified dietitians. A questionnaire designed to assess diet acceptability was administered at months 4, 8, 11, and 15. Demographic measures were collected at the onset of the study.

STATISTICAL ANALYSIS PERFORMED

Statistical procedures included factor analysis and regression analysis.

RESULTS

Regression analysis suggested that perceived effectiveness of the dietary intervention and mothers' having few concerns about disadvantages of the diet were significantly related to higher overall fat intake in children in one-parent families. Maternal willingness to implement the diet was significantly related to lower saturated fat intake.

APPLICATIONS/CONCLUSIONS

In attempts to change eating behavior of children, interest and cooperation of the parents are essential to achieving successful results. These analyses further suggest that maternal acceptability translates into willingness to implement the diet and may facilitate changes that are associated with reduced saturated fat intake in children.

Effects of diet and sexual maturation on low-density lipoprotein cholesterol during puberty: the Dietary Intervention Study in Children (DISC)

BACKGROUND

The Dietary Intervention Study in Children (DISC) is a multicenter, randomized, controlled clinical trial designed to examine the efficacy and safety of a dietary intervention to reduce serum LDL cholesterol (LDL-C) in children with elevated LDL-C.

METHODS AND RESULTS

The effects of dietary intake of fat and cholesterol and of sexual maturation and body mass index (BMI) on LDL-C were examined in a 3-year longitudinal study of 663 boys and girls (age 8 to 10 years at baseline) with elevated LDL-C levels. Multiple linear regression was used to predict LDL-C at 3 years. For boys, LDL-C decreased by 0.018 mmol/L for each 10 mg/4.2 MJ decrease in dietary cholesterol (P<.05). For girls, no single nutrient was significant in the model, but a treatment group effect was evident (P<.05). In both sexes, BMI at 3 years and LDL-C at baseline were significant and positive predictors of LDL-C levels. In boys, the average LDL-C level was 0.603 mmol/L lower at Tanner stage 4+ than at Tanner stage 1 (P<.01). In girls, the average LDL-C level was 0.274 mmol/L lower at Tanner stage 4+ than at Tanner stage 1 (P<.05).

CONCLUSIONS

In pubertal children, sexual maturation, BMI, dietary intervention (in girls), and dietary cholesterol (in boys) were significant in determining LDL-C. Sexual maturation was the factor associated with the greatest difference in LDL-C. Clinicians screening for dyslipidemia or following dyslipidemic children should be aware of the powerful effects of pubertal change on measurements of lipoproteins.

Safety of a fat-reduced diet: the Dietary Intervention Study in Children (DISC)

OBJECTIVE

To assess the relationship between energy intake from fat and anthropometric, biochemical, and dietary measures of nutritional adequacy and safety.

DESIGN

Three-year longitudinal study of children participating in a randomized controlled trial; intervention and usual care group data pooled to assess effects of self-reported fat intake; longitudinal regression analyses of measurements at baseline, year 1, and year 3.

PARTICIPANTS

Six hundred sixty-three children (362 boys and 301 girls), 8 to 10 years of age at baseline, with elevated low-density lipoprotein cholesterol, who are participants of the Dietary Intervention Study in Children.

MEASURES

Energy intake from fat assessed from three 24-hour recalls at each time point was the independent variable. Outcomes were anthropometric measures (height, weight, body mass index, and sum of skinfolds), nutritional biochemical determinations (serum ferritin, zinc, retinol, albumin, beta-carotene, and vitamin E, red blood cell folate, and hemoglobin), and dietary micronutrients (vitamins A, C, E, thiamin, riboflavin, niacin, vitamins B-6, B-12, folate, calcium, iron, zinc, magnesium, and phosphorus).

RESULTS

Lower fat intake was not related to anthropometric measures or serum zinc, retinol, albumin, beta-carotene, or vitamin E. Lower fat intake was related to: 1) higher levels of red blood cell folate and hemoglobin, with a trend toward higher serum ferritin; 2) higher intakes of folate, vitamin C, and vitamin A, with a trend toward higher iron intake; 3) lower intakes of calcium, zinc, magnesium, phosphorus, vitamin B-12, thiamin, niacin, and riboflavin; 4) increased risk of consuming less than two-thirds of the Recommended Dietary Allowances for calcium in girls at baseline, and zinc and vitamin E in boys and girls at all visits.

CONCLUSIONS

Lower fat intakes during puberty are nutritionally adequate for growth and for maintenance of normal levels of nutritional biochemical measures, and are associated with beneficial effects on blood folate and hemoglobin. Although lower fat diets were related to lower self-reported intakes of several nutrients, no adverse effects were observed on blood biochemical measures of nutritional status. Current public health recommendations for moderately lower fat intakes in children during puberty may be followed safely.

Nutrient intake and blood pressure in the Dietary Intervention Study in Children

Delineating the role that diet plays in blood pressure levels in children is important for guiding dietary recommendations for the prevention of hypertension. The purpose of this study was to investigate relationships between dietary nutrients and blood pressure in children. Data were analyzed from 662 participants in the Dietary Intervention Study in Children who had elevated low-density lipoprotein cholesterol and were aged 8 to 11 years at baseline. Three 24-hour dietary recalls, systolic pressure, diastolic pressure, height, and weight were obtained at baseline, 1 year, and 3 years. Nutrients analyzed were the micronutrients calcium, magnesium, and potassium; the macronutrients protein, carbohydrates, total fat, saturated fat, polyunsaturated fat, and monounsaturated fat; dietary cholesterol; and total dietary fiber. Baseline and 3-year longitudinal relationships were examined through multivariate models on diastolic and systolic pressures separately, controlling for height, weight, sex, and total caloric intake. The following associations were found in longitudinal analyses: analyzing each nutrient separately, for systolic pressure, inverse associations with calcium (P < .05); magnesium, potassium, and protein (all P < .01); and fiber (P < .05), and direct associations with total fat and monounsaturated fat (both P < .05); for diastolic pressure, inverse associations with calcium (P < .01); magnesium and potassium (both P < .05), protein (P < .01); and carbohydrates and fiber (both P < .05), and direct associations with polyunsaturated fat (P < .01) and monounsaturated fat (P < .05). Analyzing all nutrients simultaneously, for systolic pressure, direct association with total fat (P < .01); for diastolic pressure, inverse associations with calcium (P < .01) and fiber (P < .05), and direct association with total and monounsaturated fats (both P < .05). Results from this sample of children with elevated low-density lipoprotein cholesterol indicate that dietary calcium, fiber, and fat may be important determinants of blood pressure level in children.

Adherence to dietary recommendations in the special intervention group in the Multiple Risk Factor Intervention Trial

This chapter presents findings on adherence to the Multiple Risk Factor Intervention Trial eating pattern by special intervention participants, on the basis of measures other than the 24-h dietary recall and blood cholesterol concentrations. These additional assessments included subjective ratings by a nutritionist, used during follow-up years 1 and 2, and a food record rating that was calculated from a 3-d food record, used during years 3-6. An additional tool used during the latter part of the trial was a checklist for evaluating degree of shortfall of the participant's diet from recommendations, level of motivation toward adherence, and factors in the social environment potentially influencing dietary behavior. Subjective ratings and food record ratings indicated that approximately 40-65% of participants were good or excellent adherers, with declines in these percentages over time. There were consistent strong relations between these ratings and change in serum cholesterol. Checklist evaluations gave similar overall findings, with about one-half to three-quarters of participants rated positively on infrequency of deviation from the eating pattern, motivation, and conducive environment. Several baseline traits predicted adherence. Adherence was better in older participants, in white than in black men, in nondrinkers, in those with fewer stressful life events, in those eating away from home less often, in less overweight men (although heavier participants exhibited greater changes in serum cholesterol, perhaps reflecting their poorer baseline diets), in those with higher serum cholesterol and diastolic blood pressure, and in nonsmokers.

Low-fat diet practices of older women: prevalence and implications for dietary assessment

OBJECTIVE

To evaluate the importance of information on low-fat diet practices and consumption of reduced-fat foods for accurate assessment of energy and fat intakes using a semiquantitative food frequency questionnaire (FFQ).

SUBJECTS

Subjects were 7,419 women, aged 50 to 79 years, who filled out an FFQ as part of eligibility screening for a diet modification component and/or a hormone replacement trial in a multicenter study of chronic disease prevention in postmenopausal women (Women's Health Initiative).

STATISTICAL ANALYSIS

For 26 FFQ questions, we recoded the low-fat diet choices of participants to a high-fat counterpart and recalculated energy and fat intakes. We then determined the decrease in energy and nutrient estimates attributable to adding low-fat options to the FFQ.

RESULTS

Low-fat diet practices were widespread in this population. For example, 69% of respondents rarely or never ate skin on chicken, 76% rarely or never ate fat on meat, 36% usually drank nonfat milk, 52% usually ate low-fat or fat-free mayonnaise, 59% ate low-fat chips/snacks, and 42% ate nonfat cheese. These low-fat choices had substantial effects on energy and nutrient estimates. Absolute decreases (and mean percentage decreases) for energy and nutrient measures attributable to adding low-fat diet options to the FFQ were 196 kcal (11.4%) energy, 9 percentage points in percentage energy from fat (22.3%), 23.2 g fat (29.0%), and 9.6 g saturated fat (32.5%). Black and Hispanic women and women of lower socioeconomic status reported significantly fewer low-fat diet practices than white women and women of higher socioeconomic status.

CONCLUSION

Failure to collect information on low-fat diet practices with an FFQ will result in an upward bias in estimates of energy and fat intake, and the amount of error will vary by the personal characteristics of respondents.

Dietitians' contributions to cholesterol education: a decade of progress

ADA congratulates NCEP on 10 years of important contributions to reducing cardiovascular disease. Dietitians have played a major role in implementing dietary recommendations of the cholesterol education campaign through its members, programs, research projects, and publications. The partnership is strong and dynamic. Together, there is much to accomplish in the years ahead to further reduce the risk of cardiovascular disease and improve the nutritional status of all Americans.

Epidemiology of soy and cancer: perspectives and directions

Previous epidemiologic studies of the effects of soy protein on cancer risk have been limited by small variations in soy intake, inability to separate soy from other dietary variables and difficulties inherent in relating dietary intake to the development of cancer several decades later. As a result, although existing data suggest that soy protein may be protective for cancer risk, results are overall inconclusive. There is also evidence that soy products may affect risk factors for cancer, such as endogenous hormone levels. Preliminary data from our group indicate that young Adventist women who are vegetarians with high soy intake and a lower risk of breast cancer may have higher levels of an adrenal androgen, dehydroepiandrosterone sulfate. Other groups have noted that soy protein may be associated with alterations in the regulation and binding of ovarian hormones. Additional studies examining effects of soy protein on risk factors for cancer would help, not only in delineating mechanisms of cancer development, but also in designing dietary programs aimed at cancer prevention.

A comparison of two methods to ascertain dietary intake: the CARDIA Study

Data on dietary intake were collected in the Coronary Artery Risk Development in Young Adults (CARDIA) Study at the baseline examination in 1985-86 and again at the second examination 2 years later. At baseline, a diet history questionnaire developed for the CARDIA study was used; at the second exam the NCI (Block) food frequency questionnaire was used. The purpose of the present report is to compare the estimated nutrient intakes obtained with the two instruments; to compare correlations of nutrient intakes obtained at the two exams with those observed for other lifestyle and physiological variables also measured 2 years apart; and to assess ability to test hypotheses relating 2-year changes in risk factors to between-exam differences in reported nutrient intakes. Mean levels of reported intake were generally greater for both blacks and whites on the CARDIA diet history than on the Block food frequency. Rank order correlations of reported nutrient intakes between the two questionnaires indicated greater consistency between instruments for whites (r's ranging between 0.35 and 0.52) than for blacks (r's ranging between 0.29 and 0.45). Correlations over time for nutrients were smaller than those observed for body size measures and lipid levels but were similar in magnitude to those for blood pressure, physical activity, and life events. At both exams, total caloric intake was positively associated with physical activity (range of r's for CARDIA were 0.07 for white women to 0.23 for black men, the range of r's for Block were 0.06 for women to 0.11 for white men). Using data from the two examinations, 2-year changes in total plasma cholesterol were significantly related to 2 year changes in Keys scores. The results of this comparison are useful in that they show similarities and differences between two instruments developed to gather dietary intake data. The study also illustrates the need to monitor young adults during a time when rapid changes occur in many lifestyle and physiologic factors.

Quality control of dietary data collection in the CARDIA study

The Coronary Artery Risk Development in (Young) Adults (CARDIA) Study developed and implemented quality control (QC) measures to minimize misclassification associated with dietary data. Manual and automated data inspection were used to monitor quality. Of the 5111 participants who completed a dietary history, 717 (14%) had dietary forms reviewed and 153 (3%) had the interview audiotaped. Results show that for the 717 forms reviewed, the overall form completion error rate was 0.22% and the "critical" error rate (i.e., those errors impacting on nutrient computations) was 0.12%. The proportion of forms free of any type of error increased over time (p less than 0.0001). The discrepancy rate in recording and interviewing methods as estimated from the 153 audiotaped interviews was 0.7%. Inter-interviewer differences were small as indicated by the audiotaped interviews and the proportion of error-free forms completed by interviewers. The results indicate that the dietary data collected in CARDIA were completely and accurately recorded for use in analysis.

Symptom-limited graded treadmill exercise testing in young adults in the CARDIA study

Symptom-limited, graded exercise treadmill testing was performed by 4,968 white and black adults, ages 18-30 yr, during the baseline examination for the CARDIA study. The mean estimated maximal exercise capacity by race/gender, expressed as metabolic units (METS), was: white men 13.8, black men 13.0, white women 11.1, and black women 9.4. Exercise test duration was higher in nonsmokers, positively related to physical activity score and pulmonary function (FEV1.ht-2), and inversely related to body mass index. Men had higher mean values than women for both test duration and a measure of submaximal performance, the workload 130 (WL130, the exercise test duration to a heart rate of 130 beats.min-1). Adjusted for age and education, white men had a longer mean test duration than black men (53 s longer, P less than 0.001), but nearly equal mean WL130. White women had higher mean values than black women for both test duration (114 s longer, P less than 0.001) and WL130 (36 s longer, P less than 0.001). Men had higher mean values than women for both outcome measures (P less than 0.001). Thus, in young adults significant gender and ethnic differences exist for exercise test performance, part of which can be explained by personal habits or traits.