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PURPOSE: To validate bioimpedance spectroscopy (BIS) as a field method for measuring small, acute changes in extracellular water (ECW) during a fluid fast/rehydration manipulation. METHODS: Seventeen young adults (15 female, 2 male) participated in a 4-d fluid fast/rehydration protocol designed to induce acute changes in ECW. ECW change (DeltaECW), measured by bioimpedance spectroscopy (BIS-DeltaECW), was compared with DeltaECW, measured by bromide dilution (Br-DeltaECW), and change in body weight (DeltaBW). RESULTS: Regardless of hydration status, BIS-DeltaECW and Br-DeltaECW were similar; during dehydration, the mean difference between these two methods was 0.16 kg (P=0.61), and during rehydration, the mean difference was 0.58 kg (P=0.06). Assuming that DeltaECW=DeltaBW, DeltaECW as estimated from DeltaBW differed significantly from Br-DeltaECW, but not from BIS-DeltaECW. In addition, BIS-DeltaECW correlated significantly with DeltaBW (r=0.57 and 0.65 during dehydration and rehydration, respectively). However, the magnitude of DeltaECW impacted the accuracy of BIS-DeltaECW because BIS measures tended to overestimate DeltaECW at values between 0.0 and 1.0 kg and to underestimate changes at values above 1.0 kg. CONCLUSION: These findings suggest that BIS provides an accurate estimate of DeltaECW compared with bromide dilution during short-term changes in hydration.
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Deshidratación/diagnóstico , Impedancia Eléctrica , Análisis Espectral , Adolescente , Adulto , Arizona , Agua Corporal , Femenino , Humanos , MasculinoRESUMEN
OBJECTIVE: To develop a validated, focused Cruciferous Vegetable Food Frequency Questionnaire (FFQ) as an assessment tool for specific quantification of dietary cruciferous vegetable exposure. DESIGN/METHODS: Participants (n=107; 18 to 76 years old) completed a standard FFQ and the Cruciferous Vegetable FFQ twice over a 2-week period. Repeat dietary recalls were collected on 3 days over the same 2-week period. Urinary dithiocarbamate was determined as a biomarker of cruciferous vegetable intake. STATISTICAL ANALYSES: Descriptive statistics of intake; paired t tests and sign tests for comparison of intake estimates between instruments; Spearman correlations to assess reliability and associations between diet instruments and urinary dithiocarbamate. RESULTS: Cruciferous vegetable intake was significantly correlated between the two FFQs (r(s)=0.58), although the Cruciferous Vegetable FFQ estimated intake 35 g higher than the standard FFQ. The Cruciferous Vegetable FFQ was reliable, with a repeated measures correlation of 0.69 (P=0.01). Urinary dithiocarbamate excretion correlated with cruciferous vegetable intake from the Cruciferous Vegetable FFQ (r(s)=0.26, P<0.01), and from the standard FFQ (r(s)=0.19, P=0.06). CONCLUSIONS: The Cruciferous Vegetable FFQ provided a reproducible, valid estimate of cruciferous vegetable exposure and improved the relationship between crucifer consumption and urinary dithiocarbamate, a biomarker of cruciferous vegetable exposure. The nearly twofold difference in exposure estimates between the Cruciferous Vegetable FFQ and the standard FFQ could change the statistical significance of risk estimates in the context of epidemiological research. This questionnaire is an appropriate research tool to evaluate cruciferous vegetable intake more accurately than a standard FFQ, particularly in the context of dietary intervention studies that promote increased vegetable intake to reduce the risk for chronic disease.
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Brassicaceae , Encuestas y Cuestionarios/normas , Tiocarbamatos/orina , Adolescente , Adulto , Anciano , Biomarcadores/orina , Brassicaceae/metabolismo , Encuestas sobre Dietas , Ingestión de Alimentos , Femenino , Humanos , Masculino , Recuerdo Mental , Persona de Mediana Edad , Reproducibilidad de los Resultados , Autorrevelación , Sensibilidad y Especificidad , Estadísticas no Paramétricas , Estados UnidosRESUMEN
BACKGROUND: Excess adiposity has been shown to be associated with increased risk for breast cancer recurrence, and a plant-based eating pattern has been hypothesized to be protective. Whether a plant-based diet without specific energy goals will result in weight loss or changes in body composition in women who have been diagnosed with breast cancer has not been fully explored. AIM OF THE STUDY: This study was conducted to identify changes in body weight, anthropometric measures, and body composition over a four year period in a sub-sample of breast cancer survivors participating in a dietary intervention targeting increased intake of vegetables, fruit and fiber and decreased dietary fat intake. METHODS: This randomized, controlled dietary intervention study compared longitudinal changes in intakes, body weight, waist:hip ratio (WHR), body mass index (BMI) and body composition by treatment group among fifty-two women previously treated for Stage I, II, or IIIA breast cancer from the Arizona site of the Women's Healthy Eating and Living Study. The dietary intervention aimed for eight servings of fruit and vegetables, 30 g fiber, < or = 20% total energy from fat per day, as well as daily intake of vegetable juice. The comparison group was advised to follow general dietary guidelines for cancer prevention. RESULTS: The dietary intervention resulted in a significant and sustained increase in fiber, fruit, vegetable, and vegetable juice consumption (p < 0.05) among intervention group subjects as compared to comparison group subjects. The first 6 months resulted in a reduction in body weight and body fat among the intervention group subjects while the comparison group subjects remained stable. Subsequent measurements, at 12, 24 or 36, and 48 months, showed no significant differences in mean body weight, BMI, WHR, or body composition by study group. Also, no significant changes in these measures were demonstrated for either study group between baseline and 48 months. CONCLUSIONS: The dietary intervention efforts resulted in significant changes in diet toward an increase in plant foods and a decrease in dietary fat. Changes in weight, WHR, BMI, and body composition were not different over time or by study group assignment. Interventions that promote a plant-based diet without specific energy restriction do not appear to promote changes in body weight or body composition in women who have been diagnosed with breast cancer. To adequately examine the role of energy restriction in reducing obesity-associated breast cancer recurrence, future interventions should include prescribed energy imbalance either through reduced intake and/or increased expenditure.
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Composición Corporal , Peso Corporal , Neoplasias de la Mama/terapia , Carcinoma Ductal de Mama/terapia , Dieta con Restricción de Grasas , Fibras de la Dieta/administración & dosificación , Frutas , Verduras , Adolescente , Adulto , Anciano , Arizona/epidemiología , Índice de Masa Corporal , Femenino , Humanos , Persona de Mediana Edad , Relación Cintura-CaderaRESUMEN
BACKGROUND: The aim of this study was to measure changes in body cell mass (BCM) and quality of life in HIV-infected individuals undergoing oxandrolone therapy. Previous studies on oxandrolone have neither quantified changes in BCM using criterion methods nor quality of life using an HIV-specific instrument. METHODS: Twenty-five HIV-infected patients (15 with an AIDS diagnosis) on standard antiretroviral and nutrition management were studied before and an average of 18.6 weeks after the initiation of oxandrolone therapy, as prescribed by their primary care physician for the treatment of weight loss. BCM was estimated from intracellular water measured by multiple dilution. Lean soft tissue mass (LTM) was measured by dual-energy X-ray absorptiometry. Quality of life was evaluated by the Functional Assessment of HIV Infection (FAHI) questionnaire. RESULTS: Significant gains in body weight (2.6 +/- 3.0 kg; p < .0001), BCM (3.6 +/- 3.0 kg; p < .0001), and LTM (3.0 +/- 2.9 kg; p < .0001) occurred over an average course of 18.6 weeks of treatment. Overall quality of life improved (p = .056) and appetite improved (p = .032), both of which were positively associated with weight gain (p = .040 and p = .022, respectively). CONCLUSIONS: This is the first study involving oxandrolone therapy in HIV infection to document changes in quality of life and BCM, the metabolically active component of lean body mass that reflects nutritional status better than other more global body composition parameters. Nutritional status and quality of life can improve in HIV-infected individuals receiving a combined therapeutic approach that includes oxandrolone.