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Biomedical subjects

Cheryl L Rock

Publications and source records attributed to Cheryl L Rock.

At least 19 recordsLinked to original sources
PubMed2007

Multivitamin-multimineral supplements: who uses them?

Dietary supplement use is increasingly common in the United States. Multivitamin formulations with or without minerals are typically the most common type of dietary supplement reported in surveys and studies that collect data relating to dietary supplement use. In the National Health and Nutrition Examination Survey (NHANES) 1999-2000, 52% of adults reported taking a dietary supplement in the past month, and 35% reported regular use of a multivitamin-multimineral (MVMM) product. NHANES III data indicate an overall prevalence of dietary supplement usage of 40%, with prevalence rates of 35% in NHANES II and 23% in NHANES I. Women (versus men), older age groups, non-Hispanic whites (versus non-Hispanic blacks or Mexican Americans), and those with a higher education level, lower body mass index, higher physical activity level, and more frequent consumption of wine had a greater likelihood of reporting use of MVMM supplements in NHANES 1999-2000. Data from children suggest a similar prevalence rate, but lower prevalence rates of usage were reported in studies of adolescents. Individuals who use dietary supplements (including MVMM formulations) generally report higher dietary nutrient intakes and healthier diets in studies in which dietary data were also collected. Among adults with a history of breast or prostate cancer, usage rates for dietary supplements in general and MVMMs are considerably higher (eg, 56-57% for MVMMs), and these subgroups are more likely to also report use of single vitamin and mineral supplements. Thus, MVMM use contributes a considerable proportion of nutrient intakes in the United States and may contribute to risk of excessive intakes.

Adult↗
PubMed2006

Weight gain and recovery of pre-cancer weight after breast cancer treatments: evidence from the women's healthy eating and living (WHEL) study.

PURPOSE: To examine predictors of weight gain following breast cancer diagnosis and subsequent return to pre-cancer weight. OBJECTIVES: To determine (1) the associations of anti-neoplastic chemotherapy and/or, Tamoxifen((R)) therapy on weight change following breast cancer diagnosis, (2) whether chemotherapy modified the effect of specific demographic and tumor characteristics on weight gain, (3) the proportion and characteristics of women who gained significant weight on chemotherapy and returned to their pre-cancer weight during follow-up. SUBJECTS AND METHODS: Participants were 3088 breast cancer survivors, aged 27-74 years. Weight was measured at baseline and years 1 through 6; pre-cancer weight was self-reported. Cancer stage and treatment modalities were obtained by medical record review; demographic and physical activity data were obtained from questionnaires. Weight gain of >/=5% body weight following cancer diagnosis was considered significant. RESULTS: Chemotherapy was significantly associated with weight gain (OR = 1.65, 95% CI = 1.12, 2.43) and Tamoxifen((R)) was not (OR = 1.03, 95% CI = 0.71, 1.51). Tamoxifen((R)) did not modify the effect of either chemotherapy or its different regimens on weight gain. Both types (anthracycline: OR = 1.63, p-value = 0.01, non-anthracycline: OR = 1.79, p = 0.003) and all regimens of chemotherapy (AC: OR = 1.55, p-value = 0.01, CAF: OR = 1.83, p = 0.003, CMF: OR = 1.76, p = 0.004) were associated with weight gain but the associations were not different from one another. Only 10% of participants returned to their pre-cancer diagnosis weight at the follow-up visits; the degree of initial gain (p for trend <0.0001) predicted that return. CONCLUSION: Chemotherapy was associated with clinically meaningful weight gain, and a return to initial weight following weight gain was unlikely.

Adult↗
PubMed2006

A cognitive behavioral therapy intervention to promote weight loss improves body composition and blood lipid profiles among overweight breast cancer survivors.

UNLABELLED: Overweight or obesity is an established negative prognostic factor in breast cancer. Co-morbidities associated with obesity, including cardiovascular disease (CVD), may negatively impact quality of life and survival in this population. Our purpose was to determine the effect of a cognitive behavioral therapy (CBT) intervention for weight loss through exercise and diet modification on risk factors for recurrence of breast cancer, and risks for CVD associated with obesity. Eighty-five overweight or obese breast cancer survivors were randomly assigned to a once weekly, 16-week intervention or wait-list control group. The intervention incorporated elements of CBT for obesity, addressing a reduction in energy intake, as well exercise, with a goal of an average of 1 h a day of moderate to vigorous activity. Body weight, total and regional body fat (by dual energy X-ray absorptiometry), waist and hip circumference, and blood lipids were assessed at baseline and following 16 weeks of intervention. RESULTS: Seventy six women (89.4%) completed the intervention. Independent t-test to evaluate group differences at 16 weeks showed significant differences in weight, body mass index, percent fat, trunk fat, leg fat, as well as waist and hip circumference between intervention and control groups (P <or= 0.05). Furthermore, levels of triglycerides and total cholesterol/high density lipoprotein cholesterol levels were also significantly reduced following the intervention. These results indicate that 16 weeks of a CBT program for weight management may reduce obesity and CVD risk in overweight breast cancer survivors.

Adult↗
PubMed2006

Correlates of physical activity level in breast cancer survivors participating in the Women's Healthy Eating and Living (WHEL) Study.

BACKGROUND: Physical activity levels among breast cancer survivors are typically low, and knowledge of the correlates of increased physical activity among cancer survivors is limited. The purpose of this study was to examine factors that are associated with physical activity or inactivity among breast cancer survivors. METHODS: Data from 3088 women participating in the Women's Healthy Eating and Living (WHEL) Study, collected prior to randomization, were the focus of the current analyses. Self-reports of physical activity levels, quality of life, depression, and dietary intakes were collected. Pearson correlation analyses were employed to examine the associations among these variables, and multiple regression analyses were performed to examine the relationship between selected health behaviors and physical activity levels, after controlling for demographic, breast cancer-related, and psychosocial variables. RESULTS: Demographic and psychosocial variables were related to physical activity levels (P < 0.001 for all). Cancer treatment type and cancer stage were correlated with survivors' physical activity levels (P < 0.01), but the associations were no longer significant after controlling for demographic variables. Physical activity levels were strongly associated with other health behaviors, especially dietary intakes (P < 0.001), even after controlling for demographic, cancer-related, and psychosocial factors. CONCLUSION: Low physical activity levels in breast cancer survivors are associated with specific behavioral and other factors, which can be considered as indicators of women at higher risk. Findings of significant differences in physical activity levels based on demographic characteristics suggest the importance of promoting physical activity particularly among breast cancer survivors of ethnic minority or lower education levels.

Breast Neoplasms↗
PubMed2006

Objective cancer-related variables are not associated with depressive symptoms in women treated for early-stage breast cancer.

PURPOSE: Women with breast cancer are thought to be vulnerable to depression for reasons associated with impact of diagnosis, treatment, and metabolic/endocrine changes. While the literature shows that most of these women do not become clinically depressed, 15% to 30% report elevated depressive symptoms that may be clinically important. The purpose was to identify and determine the relative importance of predictors of depressive symptoms in women treated for early-stage breast cancer. PATIENTS AND METHODS: A total of 2,595 women (< or = 4 years following completion of initial treatment for early-stage breast cancer) provided data on cancer-related variables, personal characteristics, health behaviors, physical functioning/symptoms, and psychosocial variables. Participants were divided into high or low depressive groups using the Center for Epidemiologic Studies Depression Scale screening form. RESULTS: Results of the binary logistic regression analysis were significant (overall R2 = 32.4%). Before entry of psychosocial variables, younger age, being unmarried, poorer physical functioning, and more vasomotor and gastrointestinal symptoms were significant risk factors for elevated depressive symptoms (R2 = 16.1%), but objective cancer-related variables were not. After inclusion of psychosocial variables in the model (DeltaR2 = 16.3%), none of the preceding variables remained significant. Greater risk for depressive symptoms was associated with stressful life events, less optimism, ambivalence over expressing negative emotions, sleep disturbance, and poorer social functioning. CONCLUSION: Depressive symptoms in women treated for early-stage breast cancer are not associated with objective cancer-related factors. Rather, they are most strongly linked with many subjective psychosocial variables.

Adult↗
PubMed2006

Comparative validation of the IPAQ and the 7-Day PAR among women diagnosed with breast cancer.

BACKGROUND: The criterion-related validity and measurement bias of the long form of the International Physical Activity Questionnaire (IPAQ) was compared to the 7-Day Physical Activity Recall (PAR). METHODS: Participants were women who have been diagnosed with breast cancer and enrolled in the ongoing Women's Healthy Eating and Living Study. Women (N = 159, average age 57 years) wore an accelerometer for one week and then completed the IPAQ or the PAR. RESULTS: The validity correlation of the PAR was significantly higher (p < 0.001) than the IPAQ (0.73 vs. 0.33, respectively). The PAR and IPAQ overestimated total physical activity by 13% vs. 247%, respectively. The PAR had better sensitivity (p = 0.14) and specificity (p < .01) than the IPAQ (100% vs. 71% and 84% vs. 59%, respectively) in predicting attainment of the ACSM physical activity guideline. CONCLUSION: The PAR was superior to the IPAQ in terms of validity, measurement bias, and screening statistics.

Journal Article↗
PubMed2006

Dose escalation of a curcuminoid formulation.

BACKGROUND: Curcumin is the major yellow pigment extracted from turmeric, a commonly-used spice in India and Southeast Asia that has broad anticarcinogenic and cancer chemopreventive potential. However, few systematic studies of curcumin's pharmacology and toxicology in humans have been performed. METHODS: A dose escalation study was conducted to determine the maximum tolerated dose and safety of a single dose of standardized powder extract, uniformly milled curcumin (C3 Complextrade mark, Sabinsa Corporation). Healthy volunteers were administered escalating doses from 500 to 12,000 mg. RESULTS: Seven of twenty-four subjects (30%) experienced only minimal toxicity that did not appear to be dose-related. No curcumin was detected in the serum of subjects administered 500, 1,000, 2,000, 4,000, 6,000 or 8,000 mg. Low levels of curcumin were detected in two subjects administered 10,000 or 12,000 mg. CONCLUSION: The tolerance of curcumin in high single oral doses appears to be excellent. Given that achieving systemic bioavailability of curcumin or its metabolites may not be essential for colorectal cancer chemoprevention, these findings warrant further investigation for its utility as a long-term chemopreventive agent.

Administration, Oral↗
PubMed2006

Post-diagnosis weight gain and breast cancer recurrence in women with early stage breast cancer.

PURPOSE: To examine whether weight gain after diagnosis of breast cancer affects the risk of breast cancer recurrence. PATIENT AND METHODS: Patients included 3215 women diagnosed with early stage breast cancer (Stage I >1 cm., II, and IIIA) who were enrolled either in an observational cohort of breast cancer survivors or were part of the comparison group of a dietary intervention trial to prevent breast cancer recurrence. We computed weight change from 1 year prior to diagnosis to study enrollment. Delayed entry Cox proportional hazards models were used to evaluate associations of categories of weight change with time to recurrence, controlling for known prognostic factors. RESULTS: Neither moderate (5-10%) nor large (> 10%) weight gain (HR 0.8, 95% CI, 0.6-1.1; HR 0.9, 95% CI, 0.7-1.2, respectively) after breast cancer diagnosis was associated with an increased risk of breast cancer recurrence in the early years post-diagnosis (median time of 73.7 months from diagnosis). CONCLUSION: Our research provides evidence that weight gain commonly seen in the first several years following a breast cancer diagnosis does not increase a woman's risk for breast cancer recurrence in the first 5-7 years post-diagnosis. However, this research does not address the effects of weight gain on overall survival or on the risk of other new cancers, other prognostic outcomes of concern to the breast cancer survivor.

Adolescent↗
PubMed2006

Validity and systematic error in measuring carotenoid consumption with dietary self-report instruments.

Vegetables and fruits are rich in carotenoids, a group of compounds thought to protect against cancer. Studies of diet-disease associations need valid and reliable instruments for measuring dietary intake. The authors present a measurement error model to estimate the validity (defined as correlation between self-reported intake and "true" intake), systematic error, and reliability of two self-report dietary assessment methods. Carotenoid exposure is measured by repeated 24-hour recalls, a food frequency questionnaire (FFQ), and a plasma marker. The model is applied to 1,013 participants assigned between 1995 and 2000 to the nonintervention arm of the Women's Healthy Eating and Living Study, a randomized trial assessing the impact of a low-fat, high-vegetable/fruit/fiber diet on preventing new breast cancer events. Diagnostics including graphs are used to assess the goodness of fit. The validity of the instruments was 0.44 for the 24-hour recalls and 0.39 for the FFQ. Systematic error accounted for over 22% and 50% of measurement error variance for the 24-hour recalls and FFQ, respectively. The use of either self-report method alone in diet-disease studies could lead to substantial bias and error. Multiple methods of dietary assessment may provide more accurate estimates of true dietary intake.

Adult↗
PubMed2006

Depressive symptoms, eating psychopathology, and physical activity in obese breast cancer survivors.

Psychosocial problems such as depression are present as long-term sequelae of breast cancer and its treatment in a substantial minority of patients. In general and patient populations, lifestyle factors such as obesity and physical activity have been associated with depression, and these and related characteristics may be associated with depression in breast cancer survivors. The purpose of this cross-sectional study was to examine factors associated with depression in overweight or obese women (n=85) who had been diagnosed and treated for early stage breast cancer. Depressive symptoms were measured with the Beck depression inventory (BDI), eating psychopathology was assessed with the eating disorder examination--questionnaire (EDE-Q), and physical activity was estimated with the seven-day physical activity recall. BDI was directly correlated with global EDE-Q score (r=0.56, P<0.01) and inversely associated with age (r=-0.22, P<0.05) in bivariate analysis. Controlling for body mass index, age, education and other factors, BDI was directly associated with global EDE-Q score (P<0.001) and inversely associated with level of physical activity (P<0.05) in a model that explained 61% of the variance. Eating attitudes and behaviors, and physical activity level, are independently associated with depressive symptoms in overweight or obese breast cancer survivors.

Adult↗
PubMed2006

Recall strategies used by respondents to complete a food frequency questionnaire: an exploratory study.

The purpose of this study was to identify strategies used to recall dietary intake on a food frequency questionnaire by adults in a multiethnic sample. One-on-one interviews were conducted to identify strategies used to recall intake on the Fred Hutchinson Food Frequency Questionnaire. Twenty-eight men and 26 women in San Diego, CA (average age, 41 years), were recruited from the general community with approximately equal numbers of non-Hispanic white, African-American, and English- and Spanish-speaking Hispanic participants. Recall of food intake was most commonly guided by routines. Recall strategies differed primarily by food type and not by ethnic or sex groups. Each of nine food categories on the questionnaire was associated with a distinct pattern of recall strategies. The recall strategies identified in this study may serve as cues to be included on food frequency questionnaires to aid recall and thus improve accuracy of self-reported dietary intake.

Adult↗
PubMed2006

Using recall cues to improve measurement of dietary intakes with a food frequency questionnaire in an ethnically diverse population: an exploratory study.

OBJECTIVE: Intakes of foods based on responses to a revised food frequency questionnaire (FFQ) and the original Fred Hutchinson FFQ were compared. Revisions included the addition of foods (eg, corn tortillas), disaggregation of line items (eg, cookies vs cakes), replacing unfamiliar terms in the Spanish-language version, a food glossary, and written cues to help respondents recall their food intake. DESIGN: Adult men (46%) and women (n=105) of non-Hispanic African-American, Hispanic, and non-Hispanic white background (age range 30 to 60 years) completed two FFQs within a 1-month reference period. Participants were randomly assigned to receive the revised FFQ or Fred Hutchinson FFQ first. Primary outcome measures were frequency rates weighted by portion size for 34 foods and beverages. ANALYSES: Frequencies of food intake on the original and revised FFQs were estimated using robust means and compared using the Wilcoxon signed rank test. RESULTS: Significantly greater (P<0.05) dietary recall was obtained on the revised FFQ, on items in which foods were added or disaggregated, on traditionally Hispanic foods among Hispanic participants, and foods listed in the glossary. CONCLUSIONS: Revisions in the Fred Hutchinson FFQ resulted in significantly greater dietary recall. Despite increased length, participants believed that the food glossary and written cues were helpful in completing the revised FFQ.

Acculturation↗
PubMed2006

Responsiveness of homocysteine concentrations to food and supplemental folate intakes in smokers and never-smokers enrolled in a diet intervention trial.

We investigated circulating homocysteine concentrations in relation to smoking, folate intake (from food and supplements), serum folate concentrations, and other dietary variables. The present study is part of a parent trial assessing the effects of increasing vegetable, fruit, and fiber intakes and reducing the percentage of energy obtained from fat on breast cancer recurrence in 3,088 women previously diagnosed with breast cancer. Of the 121 smokers enrolled in the parent trial, 85 were available at baseline for the present study and were randomly matched to 85 never-smokers on baseline folate intake, age, and intervention status. Follow-up data were available on 53 smokers (22 intervention and 31 comparison) and 56 never-smokers (24 intervention and 32 comparison). No significant differences in circulating homocysteine and folate concentrations were observed between smokers and never-smokers at baseline. For smokers, significant decreases in circulating homocysteine and significant increases in folate concentrations (p < .05) from baseline to 12 months were observed in the comparison group. For never-smokers, significant decreases in circulating homocysteine and significant increases in folate concentrations were observed in the intervention and comparison groups (p < .05). In the multivariate analysis, changes in serum folate concentration and supplemental folic acid were significantly associated with change in plasma homocysteine concentrations (p < .05). These findings show that increasing supplemental folic acid can reduce homocysteine concentrations, which may have implications for lowering cardiovascular disease risk for smokers and never-smokers.

Adult↗
PubMed2006

Olestra is associated with slight reductions in serum carotenoids but does not markedly influence serum fat-soluble vitamin concentrations.

BACKGROUND: The 1996 Food and Drug Administration approval of the fat substitute olestra (sucrose polyester) called for active postmarketing surveillance because preapproval studies showed that olestra may lower circulating concentrations of fat-soluble nutrients such as vitamins and carotenoids. OBJECTIVE: The objective of the Olestra Post-Marketing Surveillance Study was to examine whether customary consumption of olestra-containing savory snacks was associated with changes in serum fat-soluble vitamin and carotenoid concentrations among free-living persons in geographically and ethnically distinct US cities. DESIGN: Adults (n = 2535) and their children aged 12-17 y (n = 272) in Baltimore, Minneapolis, and San Diego attended clinic visits during which data were collected on diet, savory snack consumption, lifestyle, and anthropometric indexes. Blood samples were drawn to assay carotenoids and vitamins A, D, E, and K. Data and blood samples were collected both before and after the nationwide introduction of olestra. General estimating equations were used in multivariate-adjusted models that examined olestra's association with the specified serum nutrients. RESULTS: Compared with no intake, the top 2 tertiles of olestra use in adults were associated with circulating carotenoid concentrations that were modestly but significantly lower (4.3% to 22.4%). There were no significant associations of olestra with any serum nutrients among adolescents. CONCLUSIONS: This active postmarketing surveillance study of a food additive suggests that small decreases in serum fat-soluble nutrients are attributable to olestra use. Although health outcomes were not measured here, it is unlikely that these small changes in nutrient measures would adversely affect health.

Adolescent↗
PubMed2006

Increases in plasma carotenoid concentrations in response to a major dietary change in the women's healthy eating and living study.

BACKGROUND: Cohort studies suggest that higher circulating carotenoid concentrations through food sources may reduce breast cancer events. Other intervention studies have not achieved the level of change in circulating carotenoids required to properly test this hypothesis. METHODS: In a randomized trial of 2,922 breast cancer survivors, we examined blood and self-reported diet at baseline and 1 year. Intensive telephone counseling encouraged a plant-based diet in the intervention group. Diet was measured via 24-hour recalls, and a panel of plasma carotenoid concentrations was assessed at both time points. RESULTS: The study intervention was associated with a 51% increase in total carotenoid concentration, from 2.272 +/- 1.294 to 3.440 +/- 2.320 micromol/L, achieved mainly by marked increases in targeted carotenoids: alpha-carotene, beta-carotene, and lutein. For each of these targeted carotenoids, the proportion of the intervention sample remaining below the cutpoint for the lowest baseline quartile decreased by one third to one half. After 1 year of study, half of the intervention group was in the highest baseline quartile. No change in distribution was observed in comparison group. Intervention participants achieved this change by both dietary pattern and vegetable juice consumption. Participants who chose to change dietary pattern without consuming significant quantities of vegetable juice achieved 75% of the level of change observed in other intervention participants. CONCLUSIONS: Innovative telephone counseling intervention and dietary targets in the Women's Healthy Eating and Living study were associated with the level of change in circulating carotenoid concentration necessary to test the diet and breast cancer hypothesis suggested by cohort studies.

Adolescent↗
PubMed2006

Curcumin content of turmeric and curry powders.

Curcumin, derived from the rhizome curcuma longa, is one of the primary ingredients in turmeric and curry powders that are used as spices in Middle Eastern and Asian countries, especially on the Indian subcontinent. More recently, laboratory studies have demonstrated that dietary curcumin exhibits various biological activities and significantly inhibits colon tumorigenesis and tumor size in animals. Curcumin displays both anti-inflammatory and antioxidant properties, giving it the potential to be considered in the development of cancer preventive strategies and applications in clinical research. Experimental studies have shown the biological activities of the compound, but much more information on pharmacokinetics, bioavailability, and food content are needed. Whether the amount of curcumin in turmeric and curry powders is sufficient to suggest effects on biological activities and cancer risk is unknown. To determine and compare the quantitative amounts of curcumin that are present in several brands of turmeric and curry powders, a high performance liquid chromatography technique was used to analyze 28 spice products described as turmeric or curry powders and two negative controls. Pure turmeric powder had the highest curcumin concentration, averaging 3.14% by weight. The curry powder samples, with one exception, had relatively small amounts of curcumin present, and the variability in content was great. The curcumin content of these seasoning products that are consumed as a component of the diet should be considered in evaluating baseline tissue concentration and response to curcumin supplementation, which is under study in chemoprevention trials.

Animals↗
PubMed2005

Tetrahydrocurcumin in plasma and urine: quantitation by high performance liquid chromatography.

Tetrahydrocurcumin (THC), one of the major metabolites of curcumin, exhibits many of the same physiologic and pharmacological activities as curcumin and in some systems may exert greater antioxidant activity than curcumin. However, evaluation of clinical efficacy is limited by lack of sensitive methods for quantifying intake/absorption in blood or urine. We have developed a sensitive high performance liquid chromatography (HPLC) analytical method for detection of THC in plasma and urine. The method involves extracting the THC from 0.2 mL samples with 95% ethyl acetate/5% methanol, and beta-17-estradiol acetate as an internal standard. Analysis with a reversed-phase C18 column and UV detection at 280 nm demonstrates linear performance from 0.050 to 6.0 microg/mL in plasma, and 0.060 to 6.0 microg/mL in urine. The coefficients of variation for intra- and inter-assays were each<8.6%. The average recovery of THC from plasma and urine was greater than 98.5%. These data demonstrate a rapid, sensitive and accurate method for HPLC quantification of THC in plasma and urine.

Administration, Oral↗