Timing of dietary change in response to a telephone counseling intervention: evidence from the WHEL study.

OBJECTIVE: Little is known about temporal patterns of diet change within interventions, nor about predictors of early and sustained successful change. Social-cognitive theory asserts that early successes in achieving behavior change increase self-efficacy, leading to longer-term success. DESIGN: The authors conducted exploratory cluster analyses using dietary data from the first month of the telephone counseling intervention of the Women's Healthy Eating and Living (WHEL) Study. MAIN OUTCOME MEASURE: Change in dietary pattern at three early intervention timepoints. RESULTS: Three clusters were identified: Cluster 1 (25%) was close to meeting study goals at baseline, but still made major changes; Cluster 2 (49%) and Cluster 3 (26%) were not achieving study goals at baseline, but Cluster 2 made substantial immediate changes, while Cluster 3 changed their diet more gradually. Baseline demographic and behavioral variables were associated with cluster membership; however, the strongest predictors of cluster were self-efficacy, motivation, and approaches to study goals. Cluster membership predicted dietary pattern at 12 months. CONCLUSION: These data suggest that a one-on-one telephone counseling intervention that is intensive in the early weeks may maximize the level of change achieved in a study.

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.

Influence of a diet very high in vegetables, fruit, and fiber and low in fat on prognosis following treatment for breast cancer: the Women's Healthy Eating and Living (WHEL) randomized trial.

CONTEXT: Evidence is lacking that a dietary pattern high in vegetables, fruit, and fiber and low in total fat can influence breast cancer recurrence or survival. OBJECTIVE: To assess whether a major increase in vegetable, fruit, and fiber intake and a decrease in dietary fat intake reduces the risk of recurrent and new primary breast cancer and all-cause mortality among women with previously treated early stage breast cancer. DESIGN, SETTING, AND PARTICIPANTS: Multi-institutional randomized controlled trial of dietary change in 3088 women previously treated for early stage breast cancer who were 18 to 70 years old at diagnosis. Women were enrolled between 1995 and 2000 and followed up through June 1, 2006. INTERVENTION: The intervention group (n = 1537) was randomly assigned to receive a telephone counseling program supplemented with cooking classes and newsletters that promoted daily targets of 5 vegetable servings plus 16 oz of vegetable juice; 3 fruit servings; 30 g of fiber; and 15% to 20% of energy intake from fat. The comparison group (n = 1551) was provided with print materials describing the "5-A-Day" dietary guidelines. MAIN OUTCOME MEASURES: Invasive breast cancer event (recurrence or new primary) or death from any cause. RESULTS: From comparable dietary patterns at baseline, a conservative imputation analysis showed that the intervention group achieved and maintained the following statistically significant differences vs the comparison group through 4 years: servings of vegetables, +65%; fruit, +25%; fiber, +30%, and energy intake from fat, -13%. Plasma carotenoid concentrations validated changes in fruit and vegetable intake. Throughout the study, women in both groups received similar clinical care. Over the mean 7.3-year follow-up, 256 women in the intervention group (16.7%) vs 262 in the comparison group (16.9%) experienced an invasive breast cancer event (adjusted hazard ratio, 0.96; 95% confidence interval, 0.80-1.14; P = .63), and 155 intervention group women (10.1%) vs 160 comparison group women (10.3%) died (adjusted hazard ratio, 0.91; 95% confidence interval, 0.72-1.15; P = .43). No significant interactions were observed between diet group and baseline demographics, characteristics of the original tumor, baseline dietary pattern, or breast cancer treatment. CONCLUSION: Among survivors of early stage breast cancer, adoption of a diet that was very high in vegetables, fruit, and fiber and low in fat did not reduce additional breast cancer events or mortality during a 7.3-year follow-up period. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00003787.

On the importance of using multiple methods of dietary assessment.

BACKGROUND: Plasma carotenoid concentrations reflect intake of vegetables and fruits, the major food sources of these compounds. This study compared the ability of 2 measures of dietary intake (24-hour diet recalls and food frequency questionnaires [FFQs]) to corroborate plasma carotenoid concentrations in a subset of women participating in a diet intervention trial. METHODS: Plasma carotenoid concentrations and dietary intakes, estimated from 24-hour diet recalls and FFQs, were examined at baseline and 1 year later in a subset of 395 study participants (197 intervention and 198 comparison group). We used longitudinal models to examine associations between estimated intakes and plasma carotenoid concentrations. These analyses were stratified by study group and adjusted for body mass index (BMI), plasma cholesterol concentration, and total energy intake. We conducted simulations to compare mean-squared errors of prediction of each assessment method. RESULTS: In mixed-effects models, the estimated carotenoid intakes from both dietary assessment methods were strongly associated with plasma concentrations of alpha-carotene, beta-carotene, and lutein. Furthermore, modeling the 2 sources of intake information as joint predictors reduced the prediction error. CONCLUSION: These findings underscore the importance of using multiple measures of dietary assessment in studies examining diet-disease associations.

Telephone counseling intervention increases intakes of micronutrient- and phytochemical-rich vegetables, fruit and fiber in breast cancer survivors.

Although a large body of evidence suggests that diet may play an important role in cancer prevention, randomized controlled trials reported to date have not achieved sufficient increases in protective micronutrients and phytochemicals to adequately test the hypothesis that diet can reduce cancer risk. The Women's Healthy Eating and Living (WHEL) Study, a randomized controlled trial of the role diet modification may play in future breast cancer events, introduced an innovative theory-based telephone counseling intervention to teach participants to consume a high fiber, low fat diet emphasizing vegetables and fruits rich in carotenoids and other potentially protective phytochemicals. This report examines the baseline to 12-mo changes in dietary intakes of 2970 participants, assessed through 24-h recalls and validated with plasma carotenoid concentrations. At 12 mo, the intervention group reported a significantly increased daily vegetable intake (+vegetable juice) of 7.1 servings (+82%) and fruit intake of 3.9 servings (+18%). Fiber intake increased from 3.04 to 4.16 g/(MJ. d), whereas energy from fat decreased significantly from 28.6 to 23.7%. Plasma carotenoid concentrations increased significantly, i.e., alpha-carotene (+223%); beta-carotene (+87%); lutein (+29%); and lycopene (+17%). In the comparison group, dietary intake and plasma carotenoid concentrations were essentially identical to those of the intervention group at baseline and were unchanged at 12 mo. The WHEL Study showed that a telephone counseling intervention can achieve major increases in micronutrient- and phytochemical-rich vegetables, fruit and fiber intakes, enabling an investigation of the potential cancer preventive effects of these food components.

Measuring dietary change in a diet intervention trial: comparing food frequency questionnaire and dietary recalls.

Measurement of dietary change was assessed in a systematic quota subsample (n = 397) of women recruited into the Women's Healthy Eating and Living Study between 1996 and 1998, a multicenter, randomized dietary intervention trial among breast cancer survivors. Women from the intervention and comparison arms completed the Arizona Food Frequency Questionnaire (AFFQ) and 24-hour dietary recalls at baseline (prerandomization) and at year 1 (postrandomization). Both dietary measurement methods demonstrated significant changes in intake of key intervention-associated nutrients at year 1 in the intervention group subjects compared with minimal or no change in the comparison group subjects. The reliability of the AFFQ and recalls was measured in the comparison group and showed correlations of 0.63 and 0.43, respectively. Both instruments captured differences in dietary intake associated with the diet intervention. These results demonstrate the utility of using a multimode, multimethod approach (AFFQ and 24-hour dietary recalls) to measure differences in self-reported dietary intake over time as shown in this dietary intervention trial being conducted among breast cancer survivors.

A randomized trial of the effect of a plant-based dietary pattern on additional breast cancer events and survival: the Women's Healthy Eating and Living (WHEL) Study.

The Women's Healthy Eating and Living (WHEL) Study is a multisite randomized controlled trial of the effectiveness of a high-vegetable, low-fat diet, aimed at markedly raising circulating carotenoid concentrations from food sources, in reducing additional breast cancer events and early death in women with early-stage invasive breast cancer (within 4 years of diagnosis). The study randomly assigned 3088 such women to an intensive diet intervention or to a comparison group between 1995 and 2000 and is expected to follow them through 2006. Two thirds of these women were under 55 years of age at randomization. This research study has a coordinating center and seven clinical sites. Randomization was stratified by age, stage of tumor and clinical site. A comprehensive intervention program that includes intensive telephone counseling, cooking classes and print materials helps shift the dietary pattern of women in the intervention. Through an innovative telephone counseling program, dietary counselors encourage women in the intervention group to meet the following daily behavioral targets: five vegetable servings, 16 ounces of vegetable juice, three fruit servings, 30 g of fiber and 15-20% energy from fat. Adherence assessments occur at baseline, 6, 12, 24 or 36, 48 and 72 months. These assessments can include dietary intake (repeated 24-hour dietary recalls and food frequency questionnaire), circulating carotenoid concentrations, physical measures and questionnaires about health symptoms, quality of life, personal habits and lifestyle patterns. Outcome assessments are completed by telephone interview every 6 months with medical record verification. We will assess evidence of effectiveness by the length of the breast cancer event-free interval, as well as by overall survival separately in all the women in the study as well as specifically in women under and over the age of 55 years.