Habitual tea consumption and risk of osteoporosis: a prospective study in the women's health initiative observational cohort.

The purpose of this study was to prospectively investigate associations of habitual drinking of regular tea with bone mineral density and fracture risk. Study participants were a multiethnic postmenopausal cohort (n = 91,465) from the nationwide Women's Health Initiative Observational Study. These women were recruited in the United States and aged 50-79 years at the time of enrollment (1994-1998). The average follow-up time was 4.1 years. Habitual consumption of regular tea was assessed with a structured questionnaire at baseline. Clinical fractures during the follow-up were reported in questionnaires, and hip fractures were further confirmed by reviewing medical records. Bone mineral density measurements were conducted among a subgroup of women (n = 4,979) at three Women's Health Initiative bone mineral density centers using dual-energy x-ray absorptiometry. Multivariate analyses suggested a positive trend of increased total body bone mineral density with tea drinking (p < 0.05). However, results from the Cox proportional hazard models did not show any significant association between tea drinking and the risk of fractures at the hip and forearm/wrist. In conclusion, the results from this study indicate that the effect of habitual tea drinking on bone density is small and does not significantly alter the risk of fractures among the US postmenopausal population.

Validation of the Arizona Activity Frequency Questionnaire using doubly labeled water.

PURPOSE: Physical activity questionnaires (PAQs) are considered the most cost-efficient method to estimate total energy expenditure (TEE) in epidemiological studies. However, relatively few PAQs have been validated using doubly labeled water (DLW) in women or in samples with diverse ethnic backgrounds. This study was conducted to validate the Arizona Activity Frequency Questionnaire (AAFQ) for estimation of TEE and physical activity energy expenditure (PAEE) over 1 month using DLW as a reference method. METHODS: Thirty-five relatively sedentary women completed the AAFQ before participating in an 8-d DLW protocol to measure TEE. TEE and PAEE were estimated from the AAFQ by calculating resting metabolic rate (RMR) using the equation of Mifflin et al. (AAFQmif), by measuring RMR using indirect calorimetry (AAFQic), and using MET conversion (AAFQmet). A predictive equation for TEE was generated. RESULTS: The mean +/- SD for TEE and PAEE from DLW were 9847 +/- 2555 kJ x d(-1) and 5578 +/- 2084 kJ x d(-1), respectively. Formulas using RMR to calculate the TEE and PAEE from the AAFQ tended to underestimate TEE and PAEE, whereas those that included only weight tended to overestimate TEE and PAEE. On the basis of the Mifflin et al. equation, the AAFQ tends to underestimate PAEE by 13%. This underestimation may be explained by the low lean body mass of the sample population and by effectiveness of the METs/RMR ratio in the obese. The following predictive equation was calculated: TEE (kJ x d(-1)) = (86.0 * average total daily METs) + (2.23 * RMRmif) - 6726. When the predictive equation is used, TEE calculated from the AAFQ is highly correlated with DLW TEE (adjusted r(2) = 0.70, P < 0.001). CONCLUSION: The AAFQ is an effective tool for the prediction of TEE and PAEE in epidemiological studies.

Effect of an integrated nutrition curriculum on medical education, student clinical performance, and student perception of medical-nutrition training.

BACKGROUND: Ninety-eight percent of medical schools report nutrition as a component of medical education. However, most schools do not have an identifiable nutrition curriculum. Medical schools that do include nutrition have not evaluated its effect on clinical skills. OBJECTIVE: The objective was to determine the efficacy of an integrated undergraduate medical curriculum to increase the quantity of nutrition instruction and to advance nutrition clinical skills demonstrated by medical students. DESIGN: A quasiexperimental design was constructed to determine whether an integrated nutrition curriculum increased the performance on nutrition-oriented clinical examinations of medical school classes that received 1, 2, or 3 y of the curriculum. The evaluation of the curriculum focused on 3 areas: 1) hours of nutrition instruction, 2) the application of nutrition within a clinical setting, and 3) perceptions about the nutrition curriculum. The Objective Structured Clinical Examination (OSCE) nutrition score was compared between graduating classes by use of analysis of variance. Data from the American Association of Medical Colleges were analyzed to determine the change in the proportion of students who reported that the amount of time devoted to nutrition was adequate. RESULTS: The implementation of the integrated nutrition curriculum resulted in a doubling of the total hours of required instruction in the medical curriculum (35 compared with 75 h). The mean (+/-1 SEM) OSCE nutrition score significantly improved after the implementation of the curriculum (41.7 +/- 0.9% compared with 50.6 +/- 1.1%) and the percentage of students who reported that the amount of nutrition taught during medical school was inadequate decreased (68.4% compared with 11.5%). CONCLUSION: Medical students improved their clinical nutrition practice skills through participation in an integrated nutrition curriculum.

Reduction in fat intake is not associated with weight loss in most women after breast cancer diagnosis: evidence from a randomized controlled trial.

BACKGROUND: A reduction in dietary fat intake has been suggested as a method to promote weight loss in women at risk for breast cancer recurrence. METHODS: Weight change in response to diet intervention was examined in 1010 women who had completed treatment for Stage I, Stage II, or Stage IIIA (American Joint Committee on Cancer staging system) primary operable breast cancer during their first year of participation in a randomized, controlled, diet intervention trial to reduce risk of recurrence. Diet intervention was performed by telephone counseling and promoted a low fat diet that also was high in fiber, vegetables, and fruit. The comparison group was provided with general dietary guidelines to reduce disease risk. Multiple linear regression models were used to examine the relations among demographic and personal characteristics, changes in diet composition and exercise level, and change in body weight or body mass index. RESULTS: The average weight change in the 1-year period was 0.04 kg for the intervention group and 0.46 kg for the comparison group. For the total group, body weight was stable (+/- 5% baseline weight) for 743 women (74%), whereas 114 (11%) lost weight, and 153 (15%) gained weight. These distributions were similar in the two study groups inclusive of all study participants and for only those women with a baseline body mass index of > or = 25 kg/m2. Initial body mass index and changes in fiber and vegetable intakes, but not change in percent of energy obtained from fat, were associated independently with change in weight or body mass index. CONCLUSIONS: For most women at risk for breast cancer recurrence, diet intervention to promote a reduction in fat intake was not associated with significant weight loss. Testing the effect of a substantial change in diet composition on risk for breast cancer recurrence is unlikely to be confounded by weight loss in subjects who were the recipients of intensive intervention efforts.

Diet and prevention of colorectal cancer.

There is a 20-fold difference in incidence rates of colorectal cancer between the areas of highest incidence (North America and Australia) and lowest incidence (India). Animal studies, epidemiologic research, and clinical trials continue to focus on diet in the search for responsible environmental factors. Between 1997 and 1999, a number of research areas have had considerable activity, and they provide the focus for this review. Among foods, vegetables, cereals, and soy have been topics of recent research. Nutrients from foods and supplements have also gained attention, including n-3 fatty acids, calcium, and B vitamins. Gene-environment interactions are beginning to be studied in populations. Studies of the interaction between polymorphisms in the gene for methylenetetrahydrofolate reductase (MTHFR) and dietary components for risk of both colorectal cancer and adenomatous polyps provide a glimpse into the future of diet and cancer research.

A qualitative study of participants' experiences with dietary assessment.

OBJECTIVE: This article reports on the use of focus groups and an experimental participatory activity to investigate factors influencing participants' decisions about what to eat and what to report on food records and food frequency questionnaires. DESIGN: Four focus groups examined participants' experience with diet records and 3 focus groups explored the topic of food portions using a group consensus activity. Twenty-two women participated in the diet record focus groups, and 15 participated in portion estimation groups. SUBJECTS: Focus group participants were equally distributed by age and body mass index values. Each woman completed a 10-day doubly labeled water protocol to measure total energy expenditure, 7 days of diet records (before and during total energy expenditure), and a food frequency questionnaire after the total energy expenditure. ANALYSIS: Transcripts of the focus groups were coded to index categories of responses and to identify themes within and across those responses. Themes discussed in this article are those that were discussed most often and at greatest length by all groups. RESULTS: The diet record focus groups revealed that 2 major factors influenced reporting on diet records: honesty vs social acceptability, and simplifying food intake. The portion estimation focus groups revealed 5 factors that influenced perceptions of portion size: the role of food in the meal, the type of food, personal preferences, product serving sizes, and comparison of personal servings with those of others. APPLICATIONS: The validity and reliability of self-reported food consumption is greatly influenced by the ways people interpret and respond to dietary assessment instruments. These findings indicate that dietetics professionals need to take extra steps to address issues of accurately recording "bad" foods when training patients to complete diet records. Extra probing is needed when dietary records do not include snacks and include simple meals and a large amount of prepared and packaged food because this may indicate that changes in normal dietary patterns were made in order to more easily complete a dietary record.

An integrated nutrition curriculum in medical education.

R25 grant support from the NIH/NCI enabled the University of Arizona to assess nutrition education, develop and evaluate specific course content, and move toward comprehensive prevention-based nutrition education in 1991-1997. Hours of nutrition education increased to 115% over baseline, and students indicated greater satisfaction with the amount of nutrition instruction they received. Especially valuable was a course in prenatal and infant nutrition that paired each student with a pregnant patient. After the grant support ended, nutrition began to be crowded out of the curriculum by other, more traditional, topics, but a 57% gain over baseline was sustained. External support for nutrition education is urgently needed.

Low-energy reporting in women at risk for breast cancer recurrence. Women's Healthy Eating and Living Group.

This study examined the extent of low-energy reporting and its relationship with demographic and lifestyle factors in women previously treated for breast cancer. This study used data from a large multisite clinical trial testing the efficacy of a dietary intervention to reduce risk for breast cancer recurrence (Women's Healthy Eating and Living Study). Using the Schofield equation to estimate energy needs and four 24-h dietary recalls to estimate energy intakes, we identified women who reported lower than expected energy intakes using criteria developed by G. R. Goldberg et al. (Eur. J. Clin. Nutr., 45: 569-581, 1991). We examined data from 1137 women diagnosed with stage I, stage II, or stage IIIA primary, operable breast cancer. Women were 18-70 years of age at diagnosis and were enrolled in the Women's Healthy Eating and Living Study between August 19, 1995, and April 1, 1998, within 4 years after diagnosis. The Goldberg criteria classified about one-quarter (25.6%) as low-energy reporters (LERs) and 10.8% as very LERs. Women who had a body mass index >30 were almost twice (odds ratio, 1.95) as likely to be LERs. Women with a history of weight gain or weight fluctuations were one and a half times as likely (odds ratio, 1.55) to be LERs as those who were weight stable or weight losers. Age, ethnicity, alcohol intake, supplement use, and exercise level were also related to LER. Characteristics (such as body mass index, age, ethnicity, and weight history) that are associated with low-energy reporting in this group of cancer survivors are similar to those observed in other populations and might affect observed diet and breast cancer associations in epidemiological studies.

Fat intake and risk of squamous cell carcinoma of the skin.

The varied effects of different classes of dietary fatty acids on carcinogenesis suggest that fatty acid composition is an important determining factor in tumor development. In the present study, we investigated the association between dietary n-3 and n-6 fatty acid intake and risk of squamous cell carcinoma of the skin (SCC). Data were taken from a population-based case-control study of skin SCC in Southeastern Arizona. Our data show a consistent tendency for a lower risk of SCC with higher intakes of n-3 fatty acids [p (for trend) = 0.055]. The adjusted odds ratios for increasing levels of n-3 fatty acids were 0.85 [95% confidence interval (CI) = 0.56-1.27] and 0.71 (95% CI = 0.49-1.00) compared with the lower level as the referent. For the ratio of n-3 to n-6 fatty acids, the odds ratios in successively higher levels were 0.88 (95% CI = 0.59-1.32) and 0.74 (95% CI = 0.51-1.05), suggesting a tendency toward decreased risk of SCC with increased intake of diets with high ratio of n-3 to n-6 fatty acid. More studies are clearly needed to elucidate the function of dietary fatty acids so that recommendations can be made to alter the human diet for cancer prevention, particularly in light of the increasing incidence of SCC of the skin.

Lack of effect of a high-fiber cereal supplement on the recurrence of colorectal adenomas. Phoenix Colon Cancer Prevention Physicians' Network.

BACKGROUND: The risks of colorectal cancer and adenoma, the precursor lesion, are believed to be influenced by dietary factors. Epidemiologic evidence that cereal fiber protects against colorectal cancer is equivocal. We conducted a randomized trial to determine whether dietary supplementation with wheat-bran fiber reduces the rate of recurrence of colorectal adenomas. METHODS: We randomly assigned 1429 men and women who were 40 to 80 years of age and who had had one or more histologically confirmed colorectal adenomas removed within three months before recruitment began to a supervised program of dietary supplementation with either high amounts (13.5 g per day) or low amounts (2 g per day) of wheat-bran fiber. The primary end point was the presence or absence of new adenomas at the time of follow-up colonoscopy. Subjects and physicians, including colonoscopists, were unaware of the group assignments. RESULTS: Of the 1303 subjects who completed the study, 719 had been randomly assigned to the high-fiber group and 584 to the low-fiber group. The median times from randomization to the last follow-up colonoscopy were 34 months in the high-fiber group and 36 months in the low-fiber group. By the time of the last follow-up colonoscopy, at least one adenoma had been identified in 338 subjects in the high-fiber group (47.0 percent) and in 299 subjects in the low-fiber group (51.2 percent). The multivariate adjusted odds ratio for recurrent adenoma in tile high-fiber group, as compared with the low-fiber group, was 0.88 (95 percent confidence interval, 0.70 to 1.11; P=0.28), and the relative risk of recurrence according to the number of adenomas, in the high-fiber group as compared with the low-fiber group, was 0.99 (95 percent confidence interval, 0.71 to 1.36; P=0.93). CONCLUSIONS: As used in this study, a dietary supplement of wheat-bran fiber does not protect against recurrent colorectal adenomas.

Citrus peel use is associated with reduced risk of squamous cell carcinoma of the skin.

Limonene has demonstrated efficacy in preclinical models of breast and colon cancers. The principal sources of d-limonene are the oils of orange, grapefruit, and lemon. The present case-control study was designed to determine the usual citrus consumption patterns of an older Southwestern population and to then evaluate how this citrus consumption varied with history of squamous cell carcinoma (SCC) of the skin. In this Arizona population, 64.3% and 74.5% of the respondents reported weekly consumption of citrus fruits and citrus juices, respectively. Orange juice (78.5%), orange (74.3%), and grapefruit (65.3%) were the predominant varieties of citrus consumed. Peel consumption was not uncommon, with 34.7% of all subjects reporting citrus peel use. We found no association between the overall consumption of citrus fruits [odds ratio (OR) = 0.99, 95% confidence interval (CI) = 0.73-1.32] or citrus juices (OR = 0.97, 95% CI = 0.71-1.31) and skin SCC. However, the most striking feature was the protection purported by citrus peel consumption (OR = 0.66, 95% CI = 0.45-0.95). Moreover, there was a dose-response relationship between higher citrus peel in the diet and degree of risk lowering. This is the first study to explore the relationship between citrus peel consumption and human cancers. Our results show that peel consumption, the major source of dietary d-limonene, is not uncommon and may have a potential protective effect in relation to skin SCC. Further studies with large sample sizes are needed to more completely evaluate the interrelationships between peel intake, bioavailability of d-limonene, and other lifestyle factors.

Reliability and validity of a self-administered food frequency questionnaire in a chemoprevention trial of adenoma recurrence.

Various chemoprevention trials have assessed dietary intake by means of food frequency questionnaires. However, it is important to assess the degree to which such questionnaires can measure diet. We conducted reproducibility and validity analyses of our Arizona Food Frequency Questionnaire (AFFQ) in our recently completed, randomized, Phase III chemoprevention trial testing the effects of a wheat bran fiber supplement on colorectal adenoma recurrence. A total of 139 individuals provided a baseline and year 1 AFFQ and a set of 4-day dietary records collected over a period of 1 month. The reproducibility analyses of the AFFQ administered 1 year apart showed a mean intraclass correlation of 0.54 for unadjusted nutrients and 0.48 for energy-adjusted nutrients. The relative validity of the AFFQ, as compared with the average of the 4-day diet records, showed a mean deattenuated correlation of 0.49 (range, 0.22-0.65) for the baseline AFFQ and 0.49 (range, 0.25-0.67) for the year 1 AFFQ. When data from both AFFQs were combined and compared with the diet records, there was a slight improvement in the overall deattenuated correlations (mean, 0.56; range, 0.33-0.71). The correlations we observed for macro- and micronutrient intake were within the overall range of those reported in the literature. Reliability and validity studies of dietary instruments are feasible in the setting of a chemoprevention trial and should be conducted when the instrument's performance has not been previously assessed in the target population.

Confidence of health professionals in public health approaches to obesity prevention.

OBJECTIVE: To assess the views of professionals working in the obesity field on the potential usefulness and feasibility of implementing different types of public health prevention strategies. METHOD: A questionnaire listing 20 public health strategies was mailed to pre-registrants of an international obesity prevention symposium. Respondents were asked to rate how useful and how feasible they felt each of the listed actions would be for the prevention of obesity in their home countries. The list included education-based strategies aimed at changing individual behaviour as well as more radical measures aimed at reducing population exposure to obesity-promoting factors in the environment. RESULTS: A 32% response was obtained. Education-based strategies were seen to be both useful and feasible. Less confidence was expressed in strategies aimed at changing the environment. CONCLUSION: People working in the obesity field tend to feel most comfortable with education-based prevention strategies. Implementation of environment-based strategies needed to encourage and support behaviour change may require the involvement of people from relevant sectors outside the obesity field.

The association of energy intake bias with psychological scores of women.

OBJECTIVE: Assess the association between reporting bias of dietary energy intake and the behavioral and psychological profiles in women. DESIGN: At baseline a series of questionnaires were administered to 37 women, (the Marlowe-Crowne Social Desirability Scale, Weinberger Adjustment Inventory (WAI), the Eating Disorder Inventory (EDI), the Restraint Scale and Sorensen-Stunkard's silhouettes). Subjects received training on how to record dietary records. Subjects recorded three days of dietary records to measure energy intake (EI) during a study to determine total energy expenditure (TEE) using doubly labeled water. Reporting accuracy (RA = EI/TEE x 100) was determined for each subject. Statistical analysis of the data used a mixed effects model accounting for within subject variability to determine if the psychological scores were associated with reporting accuracy. SETTING AND SUBJECT: Women were recruited with local advertisements in Tucson, Arizona. The women had a mean ( +/- 1 s.d.) age of 43.6 +/- 9.3 yrs, body mass index (BMI) of 28.7 +/- 8.5 kg/m2 and total body fat (%TBF) of 31.9 +/- 7.3%. RESULTS: Age and %TBF were significantly and inversely associated with RA. Furthermore, Social Desirability was negatively associated with RA. Body dissatisfaction and associating a smaller body size than one's own as being more healthy were also associated with a lower RA. CONCLUSIONS: These results suggest that Social Desirability and self image of body shape are associated with RA. Modifications in subject training may reduce the effect of these factors on RA.

Estrogen profiles in postmenopausal African-American women in a wheat bran fiber intervention study.

High dietary fiber intake has been hypothesized to lower blood estrogen concentrations, an effect thought to be beneficial for decreasing breast cancer risk. This study investigated the association between dietary supplementation of wheat bran and circulating estrogen levels in postmenopausal African-American women participating in a community intervention trial. Seventeen postmenopausal women (aged 63 +/- 1.6 yr) participated in the study. Nutritional status was assessed and blood and 24-hour urine samples were collected before and after five to six weeks of daily supplementation of the diet with 35 g of wheat bran cereal (11.6 g insoluble dietary fiber) marked with 28 mg of riboflavin. Riboflavin confirmed that all postmenopausal participants adhered to the intervention protocol. Nine of the 17 postmenopausal women were taking some form of estrogen replacement therapy (PM-ERT). Baseline hormone levels in the PM-ERT group did not significantly change after the dietary intervention. Estradiol (96.8 +/- 20.3 vs. 113.8 +/- 23.3 pg/ml), androstenedione (0.47 +/- 0.06 vs. 0.45 +/- 0.06 ng/ml), and sex hormone-binding globulin (SHBG, 107 +/- 13.5 vs. 106.6 +/- 13.3 nmol/l) levels remained constant. In the eight postmenopausal women who were not receiving exogenous hormones (PM), wheat bran consumption was not associated with predicted decreased levels of estradiol (25.7 +/- 2.7 vs. 31.0 +/- 1.9 pg/ml), estrone (38.3 +/- 10.1 vs. 39.3 +/- 10.6 pg/ml), and androstenedione (0.78 +/- 0.08 vs. 0.68 +/- 0.11 ng/ml) or with increased concentrations of SHBG (35.2 +/- 6.4 vs. 34.8 +/- 6.5 nmol/l). Participants receiving ERT had baseline and postintervention levels of estradiol and SHBG significantly higher and androstenedione significantly lower than those not receiving ERT. No association between wheat bran supplementation and hormone levels was found in PM or PM-ERT African-American participants. These results in postmenopausal women are in contrast to findings of earlier studies in premenopausal women indicating that wheat bran fiber decreases serum sex hormones. Estrogen levels in postmenopausal women are only 5-10% of those in premenopausal women; therefore, a high wheat bran fiber diet alone may not be sufficient to depress these low levels even further.

Design and baseline characteristics of study participants in the Wheat Bran Fiber trial.

The Wheat Bran Fiber (WBF) trial is a Phase III clinical trial designed to assess the effect of a WBF intervention for 3 years on the recurrence of adenomatous polyps. Men and women, 40-80 years of age, who had removal of one or more colorectal adenoma(s) 3 mm or larger within 3 months prior to study entry were recruited from three sites in the Phoenix metropolitan area. After meeting eligibility criteria, 1509 individuals entered a 6-week run-in period, consisting of a low WBF (2 g/day) intervention. Participants (n = 1429) successfully completed this phase and were randomized to a high (13.5 g/day) or low (2 g/day) WBF intervention. Various data and specimens were collected at baseline and throughout the intervention phase, which included dietary intake, physical activity, other risk factor information, blood specimens, rectal biopsies, and polyp tissues. The study design called for a colonoscopy at approximately 1 year after the qualifying colonoscopy; thus, the period between the first year and the final colonoscopy will be used to assess the effect of the intervention, which is expected to be completed in the latter part of 1998.

Development of a primary prevention program: insight gained in the Zuni Diabetes Prevention Program.

Diabetes prevention programs are essential in Native American communities that are experiencing high rates of non-insulin dependent diabetes mellitus (NIDDM). These programs must be community based and supported in order to succeed. The Zuni Diabetes Prevention Program (Program) is a community-based primary prevention project designed to reduce the prevalence of diabetes risk factors among high-school-age youths. The Program strives to enhance knowledge of diabetes and to support increased physical activity, increased fruit and vegetable intake, and reduced soft drink consumption. The primary mechanisms of intervention are diabetes education, a school-based wellness center, supportive social networks, and modification of the food supply available to teens. Program evaluation uses a multiple cross-sectional model; assessment occurs at three points within the 4-year project. Midproject results indicate a significant reduction in soft drink consumption and an increase in glucose/insulin ratios, suggesting a decline in the incidence of hyperinsulinemia.