Identifying factors associated with effective treatment for childhood obesity is important to imp... more Identifying factors associated with effective treatment for childhood obesity is important to improving weight loss outcomes. The current study investigated whether child or parent motivation throughout the course of treatment predicted reductions in BMI. Fifty 8- to 12-year-old children with overweight and obesity (BMI percentiles 85-98%) and their parents participated in a guided self-help weight loss program, which included 12 brief sessions across 5 months. Parents and interventionists reported on child and parent motivation level at each session. Multilevel slopes-as-outcome models were used to examine growth trajectories for both child and parent BMI across sessions. Greater interventionist-rated child motivation predicted greater reductions in child BMI; parent motivation did not. However, interventionist-rated parent motivation predicted greater reductions in parent BMI, and its impact on BMI became more pronounced over the course of treatment, such that sustained motivation...
Advances in information technology and near ubiquity of the Internet have spawned novel modes of ... more Advances in information technology and near ubiquity of the Internet have spawned novel modes of communication and unprecedented insights into human behavior via the digital footprint. Health behavior randomized controlled trials (RCTs), especially technology-based, can leverage these advances to improve the overall clinical trials management process and benefit from improvements at every stage, from recruitment and enrollment to engagement and retention. In this paper, we report the results for recruitment and retention of participants in the SMART study and introduce a new model for clinical trials management that is a result of interdisciplinary team science. The MARKIT model brings together best practices from information technology, marketing, and clinical research into a single framework to maximize efforts for recruitment, enrollment, engagement, and retention of participants into a RCT. These practices may have contributed to the study's on-time recruitment that was with...
Hispanics are a heterogeneous group of individuals with a variation in dietary habits that is ref... more Hispanics are a heterogeneous group of individuals with a variation in dietary habits that is reflective of their cultural heritage and country of origin. It is important to identify differences in their dietary habits because it has been well established that nutrition contributes substantially to the burden of preventable diseases and early deaths in the United States. We estimated the distribution of usual intakes (of both food groups and nutrients) by Hispanic and Latino backgrounds by using National Cancer Institute methodology. The Hispanic Community Health Study/Study of Latinos is a population-based cohort study that recruited participants who were 18-74 y of age from 4 US cities in 2008-2011 (Miami, Bronx, Chicago, and San Diego). Participants who provided at least one 24-h dietary recall and completed a food propensity questionnaire (n = 13,285) were included in the analyses. Results were adjusted for age, sex, field center, weekend, sequencing, and typical amount of intak...
Understanding the characteristics of young adults who have difficulty achieving a healthy weight ... more Understanding the characteristics of young adults who have difficulty achieving a healthy weight may help develop more effective interventions. Signal detection was conducted to identify subgroups of overweight/obese young adults more or less likely to lose weight (5% weight loss) over 6 months. Data were collected from a diverse sample involved in a randomized controlled behavioral weight loss intervention (N = 404). Overall, 15% (N = 57) of participants achieved <5% weight loss. Change in self-monitoring weight, baseline score of gym attendance/participating in exercise classes, and change in eating less fat were the best predictors of weight loss. These strategies may be particularly helpful to promote short-term weight loss in overweight/obese young adults.
Diet may substantially alter prostate cancer initiation and progression. However, large-scale cli... more Diet may substantially alter prostate cancer initiation and progression. However, large-scale clinical trials of diet modification have yet to be performed for prostate cancer. The Men's Eating and Living (MEAL) Study (CALGB 70807 [Alliance]) is investigating the effect of increased vegetable consumption on clinical progression in men with localized prostate cancer. MEAL is a randomized, phase III clinical trial designed to test whether an intervention that increases vegetable intake will decrease the incidence of clinical progression in men with clinically localized prostate cancer on active surveillance. We are randomizing 464 patients to either a validated telephone-based diet counseling intervention or a control condition in which patients receive a published diet guideline. The intervention will continue for two years. The primary outcome variable is clinical progression defined by serum prostate-specific antigen (PSA) and pathological findings on follow-up prostate biopsy....
Little is known about the feasibility and acceptability of tailored text message based weight los... more Little is known about the feasibility and acceptability of tailored text message based weight loss programs for English and Spanish-language speakers. This pilot study evaluated the feasibility, acceptability, and estimated impact of a tailored text message based weight loss program for English and Spanish-language speakers. The purpose of this pilot study was to inform the development of a full-scale randomized trial. There were 20 overweight or obese participants (mean age 40.10, SD 8.05; 8/20, 40% male; 9/20, 45% Spanish-speakers) that were recruited in San Diego, California, from March to May 2011 and evaluated in a one-group pre/post clinical trial. For 8 weeks, participants received and responded to 3-5 text messages daily sent from a fully automated text messaging system. They also received printed weight loss materials and brief 10-15 minute weekly counseling calls. To estimate the impact of the program, the primary outcome was weight (kg) measured during face-to-face measur...
Dietary supplements have been suggested to have a role in cancer prevention and treatment. The pu... more Dietary supplements have been suggested to have a role in cancer prevention and treatment. The purpose of this study was to describe the nutrient intakes from foods and dietary supplements in women at the time of enrollment into a clinical trial to prevent breast cancer recurrence. Subjects were within four years of diagnosis with Stage I, II, or IIIA breast cancer and had completed medical treatment (n = 435). Intakes were assessed with four 24-hour recalls over two weeks. Dietary nutrient intakes in supplement users were compared with intakes in nonusers, and supplement nutrient intakes in participants consuming diets providing < 75% were compared with those in participants consuming > or = 75% of recommended levels. Intakes of participants with diets meeting general guidelines for disease prevention were compared with intakes of those whose diets did not meet these guidelines. Dietary supplement use was reported by 352 (80.9%) of the participants, but frequency of excess intakes did not exceed 5% for all micronutrients examined. Women whose diets provided higher levels of most vitamins and minerals were more likely to obtain additional amounts of these micronutrients from dietary supplements. Participants reporting use of any supplement consumed diets providing more dietary fiber (p < 0.04) and less dietary fat (p < 0.001) than nonusers of any supplement. These results illustrate the importance of monitoring dietary supplement use in clinical trials with a focus on preventing cancer recurrence, because supplements can contribute substantially to nutrient intakes in the population under study.
Among patients with breast cancer, tumors that contain estrogen receptors (ER) are associated wit... more Among patients with breast cancer, tumors that contain estrogen receptors (ER) are associated with improved survival and better response to hormone therapy than those not expressing these receptors. The purpose of these case comparison studies was to examine the relationship between carotenoids, vitamin A, and the tumor ER status in women at diagnosis of primary breast cancer. The focus of the first study was the relationship between dietary intake and ER status, and the focus of the second study was the relationship between ER status and the plasma carotenoid, retinol, and tocopherol concentrations. We evaluated tumor ER status and self-reported dietary intake in 142 women and plasma concentrations of carotenoids, retinol, and tocopherols in 149 women, at diagnosis of breast cancer, before any medical or surgical treatment. In the first study the overall odds of ER-positive status were increased in relation to number of mammograms in the past five years, number of breast-fed babies, dietary carotenoid intake, and more frequent intake of yellow and green vegetables. Overall odds of ER-positive status were decreased in relation to years of oral contraceptive use and preformed vitamin A intake. In the second study older women, women with higher plasma lutein concentration, and women not using beta-carotene supplements were more likely to be ER positive, when data were adjusted for body mass index and factors that may influence breast cancer risk or hormonal status. Significant independent relationships between plasma retinol or tocopherol concentrations and ER status were not observed. The strong and independent relationships between carotenoid intake, plasma lutein concentration, and ER status may relate to observations linking a carotenoid-rich diet with improved prognosis after diagnosis of breast cancer.
Curcumin, derived from the rhizome curcuma longa, is one of the primary ingredients in turmeric a... more 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.
We investigated circulating homocysteine concentrations in relation to smoking, folate intake (fr... more 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.
Unhealthy weight loss practices are common among female college students. It is unknown if these ... more Unhealthy weight loss practices are common among female college students. It is unknown if these practices are also most common among women in the subset of overweight or obese college students or if these practices are related to depression. We examined the relationship between gender, depression, and unhealthy weight loss practices among overweight or obese college students. Students (body mass index between 25.0 and 34.9 kg/m(2)) from three Southern California universities (M(age) = 22 years, SD = 4; 70% women) were recruited from May 2011 to May 2012 for participation in a weight loss clinical trial (N = 404). Logistic regressions were performed with baseline data to assess the cross-sectional relationship between self-reported unhealthy weight loss practices and gender and depression as measured by the Center for Epidemiologic Studies Depression short form. Twenty-nine percent of participants reported engaging in at least one unhealthy weight loss behavior (e.g., fasting, purging) over the last 30 days, with no differences by gender. Self-report of at least one unhealthy weight loss behavior was associated with report of symptoms of depression (e(B) = 1.14 [confidence interval, CI: 1.08-1.20]), adjusting for potential confounders. Interactions between gender and depression were not significant (e(B) = 1.04 [CI: 0.93-1.16]). Among an overweight or obese sample of college students, unhealthy weight loss practices were equally common in both genders, and students with depressive symptomatology were at greatest risk. Obesity interventions targeting overweight or obese college students should educate both men and women about the dangers of unhealthy weight loss practices. In addition, screening for depression can help identify students who would benefit from additional supportive and coping strategies and resources.
Identifying factors associated with effective treatment for childhood obesity is important to imp... more Identifying factors associated with effective treatment for childhood obesity is important to improving weight loss outcomes. The current study investigated whether child or parent motivation throughout the course of treatment predicted reductions in BMI. Fifty 8- to 12-year-old children with overweight and obesity (BMI percentiles 85-98%) and their parents participated in a guided self-help weight loss program, which included 12 brief sessions across 5 months. Parents and interventionists reported on child and parent motivation level at each session. Multilevel slopes-as-outcome models were used to examine growth trajectories for both child and parent BMI across sessions. Greater interventionist-rated child motivation predicted greater reductions in child BMI; parent motivation did not. However, interventionist-rated parent motivation predicted greater reductions in parent BMI, and its impact on BMI became more pronounced over the course of treatment, such that sustained motivation...
Advances in information technology and near ubiquity of the Internet have spawned novel modes of ... more Advances in information technology and near ubiquity of the Internet have spawned novel modes of communication and unprecedented insights into human behavior via the digital footprint. Health behavior randomized controlled trials (RCTs), especially technology-based, can leverage these advances to improve the overall clinical trials management process and benefit from improvements at every stage, from recruitment and enrollment to engagement and retention. In this paper, we report the results for recruitment and retention of participants in the SMART study and introduce a new model for clinical trials management that is a result of interdisciplinary team science. The MARKIT model brings together best practices from information technology, marketing, and clinical research into a single framework to maximize efforts for recruitment, enrollment, engagement, and retention of participants into a RCT. These practices may have contributed to the study's on-time recruitment that was with...
Hispanics are a heterogeneous group of individuals with a variation in dietary habits that is ref... more Hispanics are a heterogeneous group of individuals with a variation in dietary habits that is reflective of their cultural heritage and country of origin. It is important to identify differences in their dietary habits because it has been well established that nutrition contributes substantially to the burden of preventable diseases and early deaths in the United States. We estimated the distribution of usual intakes (of both food groups and nutrients) by Hispanic and Latino backgrounds by using National Cancer Institute methodology. The Hispanic Community Health Study/Study of Latinos is a population-based cohort study that recruited participants who were 18-74 y of age from 4 US cities in 2008-2011 (Miami, Bronx, Chicago, and San Diego). Participants who provided at least one 24-h dietary recall and completed a food propensity questionnaire (n = 13,285) were included in the analyses. Results were adjusted for age, sex, field center, weekend, sequencing, and typical amount of intak...
Understanding the characteristics of young adults who have difficulty achieving a healthy weight ... more Understanding the characteristics of young adults who have difficulty achieving a healthy weight may help develop more effective interventions. Signal detection was conducted to identify subgroups of overweight/obese young adults more or less likely to lose weight (5% weight loss) over 6 months. Data were collected from a diverse sample involved in a randomized controlled behavioral weight loss intervention (N = 404). Overall, 15% (N = 57) of participants achieved <5% weight loss. Change in self-monitoring weight, baseline score of gym attendance/participating in exercise classes, and change in eating less fat were the best predictors of weight loss. These strategies may be particularly helpful to promote short-term weight loss in overweight/obese young adults.
Diet may substantially alter prostate cancer initiation and progression. However, large-scale cli... more Diet may substantially alter prostate cancer initiation and progression. However, large-scale clinical trials of diet modification have yet to be performed for prostate cancer. The Men's Eating and Living (MEAL) Study (CALGB 70807 [Alliance]) is investigating the effect of increased vegetable consumption on clinical progression in men with localized prostate cancer. MEAL is a randomized, phase III clinical trial designed to test whether an intervention that increases vegetable intake will decrease the incidence of clinical progression in men with clinically localized prostate cancer on active surveillance. We are randomizing 464 patients to either a validated telephone-based diet counseling intervention or a control condition in which patients receive a published diet guideline. The intervention will continue for two years. The primary outcome variable is clinical progression defined by serum prostate-specific antigen (PSA) and pathological findings on follow-up prostate biopsy....
Little is known about the feasibility and acceptability of tailored text message based weight los... more Little is known about the feasibility and acceptability of tailored text message based weight loss programs for English and Spanish-language speakers. This pilot study evaluated the feasibility, acceptability, and estimated impact of a tailored text message based weight loss program for English and Spanish-language speakers. The purpose of this pilot study was to inform the development of a full-scale randomized trial. There were 20 overweight or obese participants (mean age 40.10, SD 8.05; 8/20, 40% male; 9/20, 45% Spanish-speakers) that were recruited in San Diego, California, from March to May 2011 and evaluated in a one-group pre/post clinical trial. For 8 weeks, participants received and responded to 3-5 text messages daily sent from a fully automated text messaging system. They also received printed weight loss materials and brief 10-15 minute weekly counseling calls. To estimate the impact of the program, the primary outcome was weight (kg) measured during face-to-face measur...
Dietary supplements have been suggested to have a role in cancer prevention and treatment. The pu... more Dietary supplements have been suggested to have a role in cancer prevention and treatment. The purpose of this study was to describe the nutrient intakes from foods and dietary supplements in women at the time of enrollment into a clinical trial to prevent breast cancer recurrence. Subjects were within four years of diagnosis with Stage I, II, or IIIA breast cancer and had completed medical treatment (n = 435). Intakes were assessed with four 24-hour recalls over two weeks. Dietary nutrient intakes in supplement users were compared with intakes in nonusers, and supplement nutrient intakes in participants consuming diets providing < 75% were compared with those in participants consuming > or = 75% of recommended levels. Intakes of participants with diets meeting general guidelines for disease prevention were compared with intakes of those whose diets did not meet these guidelines. Dietary supplement use was reported by 352 (80.9%) of the participants, but frequency of excess intakes did not exceed 5% for all micronutrients examined. Women whose diets provided higher levels of most vitamins and minerals were more likely to obtain additional amounts of these micronutrients from dietary supplements. Participants reporting use of any supplement consumed diets providing more dietary fiber (p < 0.04) and less dietary fat (p < 0.001) than nonusers of any supplement. These results illustrate the importance of monitoring dietary supplement use in clinical trials with a focus on preventing cancer recurrence, because supplements can contribute substantially to nutrient intakes in the population under study.
Among patients with breast cancer, tumors that contain estrogen receptors (ER) are associated wit... more Among patients with breast cancer, tumors that contain estrogen receptors (ER) are associated with improved survival and better response to hormone therapy than those not expressing these receptors. The purpose of these case comparison studies was to examine the relationship between carotenoids, vitamin A, and the tumor ER status in women at diagnosis of primary breast cancer. The focus of the first study was the relationship between dietary intake and ER status, and the focus of the second study was the relationship between ER status and the plasma carotenoid, retinol, and tocopherol concentrations. We evaluated tumor ER status and self-reported dietary intake in 142 women and plasma concentrations of carotenoids, retinol, and tocopherols in 149 women, at diagnosis of breast cancer, before any medical or surgical treatment. In the first study the overall odds of ER-positive status were increased in relation to number of mammograms in the past five years, number of breast-fed babies, dietary carotenoid intake, and more frequent intake of yellow and green vegetables. Overall odds of ER-positive status were decreased in relation to years of oral contraceptive use and preformed vitamin A intake. In the second study older women, women with higher plasma lutein concentration, and women not using beta-carotene supplements were more likely to be ER positive, when data were adjusted for body mass index and factors that may influence breast cancer risk or hormonal status. Significant independent relationships between plasma retinol or tocopherol concentrations and ER status were not observed. The strong and independent relationships between carotenoid intake, plasma lutein concentration, and ER status may relate to observations linking a carotenoid-rich diet with improved prognosis after diagnosis of breast cancer.
Curcumin, derived from the rhizome curcuma longa, is one of the primary ingredients in turmeric a... more 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.
We investigated circulating homocysteine concentrations in relation to smoking, folate intake (fr... more 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.
Unhealthy weight loss practices are common among female college students. It is unknown if these ... more Unhealthy weight loss practices are common among female college students. It is unknown if these practices are also most common among women in the subset of overweight or obese college students or if these practices are related to depression. We examined the relationship between gender, depression, and unhealthy weight loss practices among overweight or obese college students. Students (body mass index between 25.0 and 34.9 kg/m(2)) from three Southern California universities (M(age) = 22 years, SD = 4; 70% women) were recruited from May 2011 to May 2012 for participation in a weight loss clinical trial (N = 404). Logistic regressions were performed with baseline data to assess the cross-sectional relationship between self-reported unhealthy weight loss practices and gender and depression as measured by the Center for Epidemiologic Studies Depression short form. Twenty-nine percent of participants reported engaging in at least one unhealthy weight loss behavior (e.g., fasting, purging) over the last 30 days, with no differences by gender. Self-report of at least one unhealthy weight loss behavior was associated with report of symptoms of depression (e(B) = 1.14 [confidence interval, CI: 1.08-1.20]), adjusting for potential confounders. Interactions between gender and depression were not significant (e(B) = 1.04 [CI: 0.93-1.16]). Among an overweight or obese sample of college students, unhealthy weight loss practices were equally common in both genders, and students with depressive symptomatology were at greatest risk. Obesity interventions targeting overweight or obese college students should educate both men and women about the dangers of unhealthy weight loss practices. In addition, screening for depression can help identify students who would benefit from additional supportive and coping strategies and resources.
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Papers by Cheryl Rock