Changes in food sources of dietary fat in response to an intensive low-fat dietary intervention: early results from the Women's Health Initiative

OBJECTIVE: To evaluate changes in food sources of dietary fat made by participants in the Women's Health Initiative Low-Fat Dietary Modification Trial. DESIGN: This study compares sources of dietary fat intake, estimated by a food frequency questionnaire, between intervention and control participants at baseline, 1 year (year 1) and 2 years (year 2) after randomization. The outcome measure was intake of fat in grams per day. Results are given on consumption of fat from six food groups and the intervention effect, defined as mean change in the intervention group minus the change in controls, controlling for baseline fat intake. PARTICIPANTS: 5,004 intervention and 7,426 control postmenopausal women in 40 clinical centers across the United States. RESULTS: At baseline, the major sources of fat were added fats, such as butter, oils, and salad dressings (25%); meats (21%); and desserts (13%). From baseline to year 1, the intervention group reduced fat by 24.3 g/day compared with the control group. Reductions came primarily from added fats (9.1 g/day), meats (4.6 g/day), and desserts (3.9 g/day). White people reduced added fats more than other race/ethnicity groups did, white and Hispanic people were more likely to reduce fat intake from milk and cheese compared with other groups, and Hispanics reduced fat from mixed dishes more than did other race/ethnicity groups (P<.05 for all). APPLICATIONS/CONCLUSIONS: These data indicate that women in the Women's Health Initiative dietary change intervention made substantial changes in food choices. These results can facilitate future low-fat interventions, and also offer clinical applications, by identifying foods that may be refractory to change.     

Dietary adherence in the Women's Health Initiative Dietary Modification Trial

This article describes adherence to a low-fat dietary pattern (less than 20% energy from fat, five or more fruit/vegetable and six or more grain servings daily) in Years 1 and 5 of the Women’s Health Initiative Dietary Modification Trial, which was designed to examine the effects of a low-fat dietary pattern on risk of breast and colorectal cancers and other chronic diseases in postmenopausal women. Participants were randomly assigned to a low-fat dietary intervention arm (40%, n=19,542) or a usual diet control arm (60%, n=29,294). Women in the intervention arm completed 18 group sessions during the first year, followed by quarterly annual maintenance sessions. Adherence was assessed as control minus intervention (C−I) group differences in percent total energy from fat as estimated by a food frequency questionnaire. Based on these self-reported dietary data, mean C−I was 10.9 percentage points of energy from fat at Year 1, decreasing to 9.0 at Year 5. Factors associated with poorer adherence were being older, being African American or Hispanic (compared with white), having low income, and being obese. Group session attendance was strongly associated with better dietary adherence. There are many limitations of self-reported dietary data, particularly related to social desirability and intervention-associated bias. Nonetheless, these data indicate that long-term dietary change was achieved in this clinical trial setting and reinforce the potential of the ongoing trial to answer questions of public health importance.     

Additional self-monitoring tools in the dietary modification component of The Women's Health Initiative

Self-monitoring promotes behavior changes by promoting awareness of eating habits and creates self-efficacy. It is an important component of the Women's Health Initiative dietary intervention. During the first year of intervention, 74% of the total sample of 19,542 dietary intervention participants self-monitored. As the study progressed the self-monitoring rate declined to 59% by spring 2000. Participants were challenged by inability to accurately estimate fat content of restaurant foods and the inconvenience of carrying bulky self-monitoring tools. In 1996, a Self-Monitoring Working Group was organized to develop additional self-monitoring options that were responsive to participant needs. This article describes the original and additional self-monitoring tools and trends in tool use over time. Original tools were the Food Diary and Fat Scan. Additional tools include the Keeping Track of Goals, Quick Scan, Picture Tracker, and Eating Pattern Changes instruments. The additional tools were used by the majority of participants (5,353 of 10,260 or 52% of participants who were self-monitoring) by spring 2000. Developing self-monitoring tools that are responsive to participant needs increases the likelihood that self-monitoring can enhance dietary reporting adherence, especially in long-term clinical trials.     

Results of an adjunct dietary intervention program in the Women's Health Initiative

OBJECTIVE: The purpose of this study was to develop, implement, and evaluate the efficacy of an intensive intervention program (IIP) based on motivational interviewing to motivate participants within the dietary study of the Women's Health Initiative (WHI) to meet the study's nutritional goals. SUBJECTS/DESIGN: WHI dietary intervention participants (n=175) from 3 clinical centers were randomly assigned to either intervention or control status. Participants assigned to IIP intervention received 3 individual motivational interviewing contacts from a dietitian, plus the usual WHI Dietary Intervention. Participants randomly assigned to IIP control received the usual WHI dietary modification (DM) Intervention. Percent of energy from fat was estimated at study baseline and at follow-up (1 year later) using the WHI Food Frequency Questionnaire. RESULTS: The change in percent energy from fat between IIP baseline and IIP 1-year follow-up was -1.2% for IIP intervention participants and +1.4% for IIP control participants, giving an overall difference of 2.6% (P<.001). Participants having the highest IIP baseline fat intake (>30% energy) showed the largest overall change in percent energy from fat between IIP baseline and IIP follow-up. CONCLUSIONS: The results of this study indicate that a protocol based on motivational interviewing and delivered through contacts with trained dietitians is an efficacious way to further lower dietary fat intake among participants exposed to ongoing intervention. These data will be useful in future intervention situations when there is a need to increase motivation to change.     

Predictors of dietary change and maintenance in the Women's Health Initiative Dietary Modification Trial

OBJECTIVE: To identify predictors of dietary change to and maintenance of a low-fat eating pattern (<20% energy from fat, > or = 5 servings fruits/vegetables daily, and > or = 6 servings grains daily) among a cohort of postmenopausal women. Candidate predictors included intrapersonal, interpersonal, intervention program characteristics, and clinical center. DESIGN: Longitudinal study within the Women's Health Initiative Dietary Modification Trial. Dietary change was evaluated after 1 year of participation in the Women's Health Initiative Dietary Modification Trial, and dietary maintenance after 3 years. SUBJECTS: Postmenopausal women aged 50 to 79 years at baseline who were randomized to the intervention arm of the Women's Health Initiative Dietary Modification Trial (n=19,541). STATISTICAL ANALYSIS: Univariate and multivariate linear regression analysis was performed and associations evaluated between candidate predictors and each of the three dietary goals: percent energy from fat, fruit/vegetable servings, and grain servings. RESULTS: Year 1 (change) predictors of percent energy from fat (P<0.005) included being younger (beta=2.12; 70 to 79 years vs 50 to 59 years), more educated (beta=-.69; college vs high school), more optimistic (beta=-.07), attending more sessions (beta=-.69), and submitting more self-monitoring records (beta=-.74). At year 3 (maintenance), the predictors of percent energy from fat (P<0.005) included attending more sessions (beta=-.65) and submitting more self-monitoring scores (beta=-.71). The analytic model predicted 22% of the variance in fat intake at year 1 and 27% at year 3 (P<0.01). CONCLUSIONS: The strongest predictors of dietary change and maintenance were attending intervention sessions and self-monitoring dietary intake. Novel was the finding that optimism predicted dietary change.     

Long-term maintenance of a low-fat diet: durability of fat-related dietary habits in the Women's Health Trial.

The Women's Health Trial (WHT) was a feasibility study for a randomized trial of a low-fat diet for the prevention of breast cancer. One year after the WHT was terminated, a random sample of 894 participants who had been active in the WHT for an average of 16 months (range = 5 to 37) completed questionnaires about their dietary habits (a 21-item instrument that measures five dimensions of low-fat dietary habits) and food intake (a food frequency questionnaire). Women who participated in the intervention program maintained most of the low-fat dietary habits adopted during the study: mean total fat intake increased from 37.8 g to 41.0 g and scales describing substitution of specially manufactured low-fat foods and modification of meats to be lower in fat increased only slightly (by 0.11 and 0.14, respectively, on a scale of 1 = always to 4 = never). Scales describing avoiding meat and avoiding fats as a flavoring increased by 0.23 and 0.22, respectively, which suggests some recidivism. Women in the control group lowered their dietary fat intake from 65.0 to 57.5 g, but all differences in fat intake and fat-related dietary habits scales between women in the control and intervention groups remained highly statistically significant. In multiple regression models, all five low-fat dietary habits scales were independently associated with percentage of energy from fat, but the strongest association was for avoiding fats as flavorings. These results suggest that substitutions of specially manufactured low-fat foods are easily adopted and maintained dietary changes, but that maintenance of new habits related to avoiding fats as flavorings and avoiding meat will require long-term reinforcement strategies.(ABSTRACT TRUNCATED AT 250 WORDS)     

Calcium, vitamin D supplementation, and physical function in the Women's Health Initiative

OBJECTIVES: The Women's Health Initiative (WHI) randomized trial of calcium/vitamin D supplementation found reduced bone loss with active treatment compared to placebo. Now we examine whether the treatment affected self-reported physical functioning and objective measures of physical functioning. DESIGN: A randomized, double-blind, placebo-controlled trial of 1,000 mg calcium carbonate plus 400 IU vitamin D(3) per day or matching placebo pills. SUBJECTS/SETTING: The study included 33,067 women (50 to 79 years old) at 40 US study centers. MAIN OUTCOME MEASURES: Physical functioning was assessed by questionnaire at enrollment in WHI, 1 year prior to calcium/vitamin D trial randomization and at study close-out (average follow-up 7.1 years). Objective physical performance and self-reported exercise measures were collected at WHI baseline (1 year prior to calcium/vitamin D enrollment) and 2 years and 4 years after calcium/vitamin D trial enrollment in a subsample (n=3,137). STATISTICAL ANALYSES PERFORMED: Calcium/vitamin D effects were tested in unadjusted and interaction linear models for each of the physical function measures. Covariates were baseline total calcium intake, fracture risk score, treatment arm in the hormone therapy and dietary modification trials (ie, active drug or placebo, low-fat diet intervention or usual diet, respectively) and age. RESULTS: Neither intention to treat nor high adherence analyses produced substantial effects of calcium/vitamin D compared to placebo on physical functioning or performance. The interaction analyses also did not result in differences because of calcium/vitamin D. CONCLUSIONS: As the first long-term randomized trial to examine the effectiveness of calcium and vitamin D in protecting against decline of physical functioning in older women, the results did not support benefit.     

Association between dietary fiber and markers of systemic inflammation in the Women's Health Initiative Observational Study

OBJECTIVE: Systemic inflammation may play an important role in the development of atherosclerosis, type 2 diabetes, and some cancers. Few studies have comprehensively assessed the direct relations between dietary fiber and inflammatory cytokines, especially in minority populations. Using baseline data from 1958 postmenopausal women enrolled in the Women's Health Initiative Observational Study, we examined cross-sectional associations between dietary fiber intake and markers of systemic inflammation (including serum high-sensitivity C-reactive protein [hs-CRP], interleukin-6 [IL-6], and tumor necrosis factor-alpha receptor-2 [TNF-alpha-R2]) in addition to differences in these associations by ethnicity. METHODS: Multiple linear regression models were used to assess the relation between fiber intake and makers of systemic inflammation. RESULTS: After adjustment for covariates, intakes of dietary fiber were inversely associated with IL-6 (P values for trend were 0.01 for total fiber, 0.004 for soluble fiber, and 0.001 for insoluble fiber) and TNF-alpha-R2 (P values for trend were 0.002 for total, 0.02 for soluble, and <0.001 for insoluble fibers). Although the samples were small in minority Americans, results were generally consistent with those found among European Americans. We did not observe any significant association between intake of dietary fiber and hs-CRP. CONCLUSION: These findings lend support to the hypothesis that a high-fiber diet is associated with lower plasma levels of IL-6 and TNF-alpha-R2. Contrary to previous reports, however, there was no association between fiber and hs-CRP among postmenopausal women. Future studies on the influence of diet on inflammation should include IL-6 and TNF-alpha-R2 and enroll participants from ethnic minorities.     

The evolution of a National Public Health Initiative on Diabetes and Women's Health: a model process

Diabetes is a serious chronic disease that affects women in all life stages, from adolescence to the older years. Diabetes also imposes a significant economic burden on individuals, families, and society. The National Public Health Initiative on Diabetes and Women's Health was formed to guide the nation in addressing diabetes and women's health issues. This paper documents the rationale for developing an initiative on diabetes and women's health and the processes used to implement it.     

Optimism and Diet Quality in the Women's Health Initiative

Diet quality has not been well studied in relation to positive psychological traits. Our purpose was to investigate the relationship between optimism and diet quality in postmenopausal women enrolled in the Women's Health Initiative observational study (OS) and clinical trials (CTs), and to determine whether optimism was associated with diet change after a 1-year dietary intervention. Diet quality was scored with the Alternate Healthy Eating Index (AHEI) and optimism assessed with the Life Orientation Test-Revised. Baseline characteristics were compared across AHEI quintiles or optimism tertiles using regression models with each variable of interest as a function of quintiles or tertiles (OS, n=87,630; CT, n=65,360). Association between optimism and baseline AHEI and change in AHEI over 1 year were tested using multivariate linear regression (CT, n=13,645). Potential interaction between optimism and trial arm and demographic/lifestyle factors on AHEI change was tested using likelihood ratio test (CT intervention, n=13,645; CT control, n=20,242). Women reporting high AHEI were non-Hispanic white, educated, physically active, past or never smokers, hormone therapy users, had lower body mass index and waist circumference, and were less likely to have chronic conditions. In the CT intervention, higher optimism was associated with higher AHEI at baseline and with greater change over 1 year (P=0.001). Effect modification by intervention status was observed (P=0.014), whereas control participants with highest optimism achieved threefold greater AHEI increase compared with those with the lowest optimism. These data support a relationship between optimism and dietary quality score in postmenopausal women at baseline and over 1 year.     

Desire to eat high- and low-fat foods following a low-fat dietary intervention

OBJECTIVE: This study examined changes in desires to eat high-fat and low-fat foods across an obesity treatment program. The hypotheses under examination were (1) preferences for low-fat foods would increase across time and (2) preferences for high-fat foods would decrease across time. DESIGN: Single-group, prospective examination of desires to eat 48 foods, categorized according to fat content, before and after the 16-week treatment program. SETTING: University clinic, Memphis, Tennessee. PARTICIPANTS: 118 obese (mean weight = 194.4 lbs) women (mean age = 45.24 years) participating in an obesity treatment program. INTERVENTION: A 16-week cognitive-behavioral program for obesity. VARIABLES MEASURED: Desires to eat 48 foods varying in fat content and whether or not participants actually ate these foods. ANALYSIS: Analysis of variance, multiple regression, and paired t tests. RESULTS: The results indicate that during the program, preferences for low-fat foods increased, whereas preferences for high-fat foods decreased. These changes mirrored the changes in consumption of both low-fat and high-fat foods. CONCLUSIONS AND IMPLICATIONS: Within a behavioral economic perspective, the reinforcement value of low-fat foods may increase following a low-fat dietary intervention, whereas the reinforcing properties of high-fat foods may decline. This is desirable as low-fat foods hold many advantages over high-fat foods in terms of weight maintenance.     

Telephone counseling helps maintain long-term adherence to a high-vegetable dietary pattern

Achieving long-term adherence to a dietary pattern is a challenge in many studies investigating the relationship between diet and disease. The Women's Healthy Eating and Living Study was a multi-institutional randomized trial in 3088 women at risk for breast cancer recurrence. At baseline, the average participant followed a healthy dietary pattern of 7 vegetable and fruit servings, 21 g/d of fiber, and 28.7% energy from fat, although fat intake increased over the enrollment period. Using primarily telephone counseling, the intervention group was encouraged to substantially increase intakes of vegetables, fruits, and fiber while decreasing fat intake. Sets of 24-h dietary recalls were completed on 90% of eligible participants at 1 y and 86% at 4 y. Using a conservative imputation analysis, at 1 y, the intervention group consumed 38% more vegetable servings (100% when including juice) than the comparison group, 20% more fruit, 38% more fiber, 50% more legumes, and 30% more whole grain foods, with a 20% lower intake of energy from fat. At 4 y, the between-group differences were 65% for vegetables (including juice), 25% fruit, 30% fiber, 40% legumes, 30% whole grain foods, and 13% lower intake of energy from fat. The intervention effect on fat intake was similar for early vs. late enrollees. Plasma carotenoid concentrations on a random 28% sample validated self-reported vegetable and fruit intake, with a between-group difference of 66% at 1 y and over 40% at 4 y. This large change will allow testing of hypotheses on the role of dietary change in preventing additional breast cancer events.     

The DHHS Office on Women's Health Initiative to Improve Women's Heart Health: focus on knowledge and awareness among women with cardiometabolic risk factors

Abstract Background: The diversity of the U.S. population and disparities in the burden of cardiovascular disease (CVD) require that public health education strategies must target women and racial/ethnic minority groups to reduce their CVD risk factors, particularly in high-risk communities, such as women with the metabolic syndrome (MS). Methods: The data reported here were based on a cross-sectional face-to-face survey of women recruited from four participating sites as part of the national intervention program, Improving, Enhancing and Evaluating Outcomes of Comprehensive Heart Care in High-Risk Women. Measures included baseline characteristics, sociodemographics, CVD related-knowledge and awareness, and Framingham risk score (FRS). Results: There were 443 of 698 women (63.5%) with one or more risk factors for the MS: non-Hispanic white (NHW), 51.5%; non-Hispanic black (NHB), 21.0%; Hispanic, 22.6%. Greater frequencies of MS occurred among Hispanic women (p<0.0001), those with less than a high school education (70.0%) (p<0.0001), Medicaid recipients (57.8%) (p<0.0001), and urbanites (43.3%) (p<0.001). Fewer participants with MS (62.6%) knew the leading cause of death compared to those without MS (72.1%) (p<0.0001). MS was associated with a lack of knowledge of the composite of knowing the symptoms of a heart attack plus the need to call 911 (odds ratio [OR] 0.41, 95% confidence interval [CI] 0.17-0.97, p=0.04). Conclusions: Current strategies to decrease CVD risk are built on educating the public about traditional factors, including hypertension, smoking, and elevated low-density lipoprotein cholesterol (LDL-C). An opportunity to broaden the scope for risk reduction among women with cardiometabolic risk derives from the observation that women with the MS have lower knowledge about CVD as the leading cause of death, the symptoms of a heart attack, and the ideal option for managing a CVD emergency.     

Correlates of maintenance of a low-fat diet among women in the Women's Health Trial.

BACKGROUND. The Women's Health Trial (WHT) was a feasibility study for a randomized controlled trial designed to test the hypothesis that a reduction in dietary fat reduces breast cancer incidence among women age 45 to 69. Between 1984 and 1988, 2,064 women participated in its two phases. METHODS. A follow-up study of 525 women who were randomized to receive the WHT dietary intervention program was conducted to assess maintenance of the diet 1 year on average after the trial ended. Among 448 participants, the mean percentage of energy from fat as measured by a food frequency questionnaire was 40.0% at baseline, 26.3% at the end of the trial, and 27.7% at follow-up. Based on 408 women with complete data, a recursive model was estimated, describing the influence of baseline characteristics of the women on attendance at intervention program sessions, adherence to the diet during the trial, and long-term maintenance of the diet after the trial ended. The effects of women's experiences during the trial on adherence and long-term maintenance were investigated as well. RESULTS. Attendance at the educational sessions was strongly related to adherence to the diet during the trial (P less than 0.001), and adherence was the most important predictor of long-term maintenance (P less than 0.001). The percentage of energy from dietary fat at baseline was an important correlate of both adherence (P less than 0.001) and long-term maintenance (P less than 0.001). College-educated women were more likely to adhere to the diet during the trial (P less than 0.001). Feelings of deprivation adversely affected long-term maintenance (P less than 0.01), primarily through their effect on adherence during the trial (P = 0.01). Costliness of the diet in time and money negatively influenced long-term maintenance (P less than 0.05). Development of a distaste for fat encouraged adherence (P = 0.06). CONCLUSIONS. The low-fat dietary pattern established during the WHT was maintained for as long as 20 months after the trial ended. A recursive model was useful in analyzing the process and correlates of long-term maintenance of dietary behavior change. Both predisposing variables and women's experiences while on a low-fat diet were associated with long-term maintenance. The results suggest that feelings of deprivation should be avoided, perhaps by use of low-fat substitutes, by those attempting to lower their dietary fat and that more research is needed on the development of a distaste for fat among individuals who adopt low-fat diets.     

Feasibility of a randomized trial of a low-fat diet for the prevention of breast cancer: dietary compliance in the Women's Health Trial Vanguard Study

The Women's Health Trial Vanguard Study was conducted to examine the feasibility of a nationwide, randomized multicenter intervention trial to test the hypothesis that a low-fat diet followed for a period of 10 years will reduce breast cancer risk. Women ages 45-69 years at increased risk of breast cancer were randomized into intervention (low-fat diet, n = 184) and control (usual diet, n = 119) groups. On the basis of 4-day food records, baseline fat intakes were comparable in the two groups, averaging 1,718 kcal with 39% of energy as fat. Intervention women reported substantially lower fat intake at 6 (20.9% kcal), 12 (21.6%), and 24 months (22.6% kcal). In contrast, control women reported only slight reductions in fat intake (37.3% kcal at 12 months and 36.8% kcal at 24 months). Evidence that these women were indeed complying with the low-fat dietary intervention comes from (a) the reasonable nature of reported nutrient changes within food groups in the intervention women and (b) agreement between observed and expected differences in plasma total cholesterol between the control and the intervention groups. At 12 months, the observed control - intervention plasma cholesterol difference was 13.1 +/- 4.6 mg/dl while the expected difference based on the Keys equation was 15.1 +/- 1.1 mg/dl; at 24 months, the observed difference was 15.5 +/- 4.3 mg/dl and the expected difference was 12.0 +/- 1.2 mg/dl. These analyses indicate that the intervention women made substantial dietary changes and have successfully maintained these changes over a 2-year period. This study thus demonstrates the feasibility of a randomized trial with an intensive low-fat dietary intervention.