Omega-3 fatty acids and cancer risk.
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Animals↗
Biomedical subjects
Janet A Tooze
Publications and source records attributed to Janet A Tooze.
Negative energy balance induced by voluntary wheel running inhibits polyp development in APCMin mice.
Treadmill running of approximately 0.9 km/day has had inconsistent effects on spontaneous intestinal polyp development in C57BL/6J-Apc(Min)/J (Min) mice; the amount of energy expenditure and/or a lack of hormonal changes could account for this variability. The purpose of this study was to examine the effects of a negative energy balance induced by voluntary wheel running on polyps, insulin-like growth factor-1 (IGF-1) and corticosterone in Min mice. Seven-week-old male Min mice were randomly assigned to control (CON, n = 23) or wheel running (EX, n = 24) conditions for a 10-week study period. All mice had water and AIN-76A diet ad libitum for the first approximately 3 weeks on study, after which the EX group was pair-fed to the CON group to maintain a negative energy balance due to the exercise. EX mice voluntarily ran 3.8 km/day (2.7-6.0 km/day) (median, interquartile range) and weighed less than CON mice throughout the study. More CON mice died before the end of the study versus EX mice (26 versus 0%, P < 0.01). CON mice had significantly more polyps versus EX mice (21.6 +/- 1.5 versus 16.9 +/- 2.0, P < 0.01; mean +/- SE), and daily running distance in EX was inversely correlated with total polyp number (r = -0.70, P < 0.01). Urinary corticosterone output (P < 0.01) and serum IGF-1 were significantly higher in EX than CON (P < 0.001); however, total polyp number was unrelated to corticosterone (r = 0.05, P = 0.84) and IGF-1 (r = -0.01, P = 0.93). In this study, a negative energy balance produced by wheel running exercise and restricted feeding decreased polyp burden in male Min mice and appeared to have a dose-response effect on polyp number. Although EX affected IGF-1 and corticosterone, neither marker was related to total polyp number.
Animals↗
The food propensity questionnaire: concept, development, and validation for use as a covariate in a model to estimate usual food intake.
OBJECTIVE: Twenty-four-hour recalls capture rich information on food consumption, but suffer from inadequately measuring usual intakes of episodically consumed foods. We explore using food frequency questionnaire (FFQ) data as covariates in a statistical model to estimate individual usual intakes of episodically consumed foods and their distributions and describe the development of the Food Propensity Questionnaire, an FFQ introduced in the 2003-2004 National Health and Nutrition Examination Survey. DESIGN: We analyzed data from 965 adult participants in the Eating at America's Table Study who completed four 24-hour recalls and an FFQ. We assessed whether or not increasing FFQ-reported frequency was associated with both number of 24-hour recall consumption days and amounts reported. RESULTS: For 52 of 56 food groups (93%), and 218 of 230 individual foods (95%), there were significant monotonically increasing relationships between FFQ frequency and 24-hour recall probability of consumption. For 47 of 56 food groups (84%) and 55 of 230 (24%) individual foods, there were significant positive correlations between FFQ frequencies and consumption-day mean intake. CONCLUSIONS: We found strong and consistent relationships between reported FFQ frequency of food and food-group consumption and probability of consumption on 24-hour recalls. This supports the premise that frequency data may offer important covariate information in supplementing multiple recalls for estimating usual intake of food groups.
Adolescent↗
A new statistical method for estimating the usual intake of episodically consumed foods with application to their distribution.
OBJECTIVE: We propose a new statistical method that uses information from two 24-hour recalls to estimate usual intake of episodically consumed foods. STATISTICAL ANALYSES PERFORMED: The method developed at the National Cancer Institute (NCI) accommodates the large number of nonconsumption days that occur with foods by separating the probability of consumption from the consumption-day amount, using a two-part model. Covariates, such as sex, age, race, or information from a food frequency questionnaire, may supplement the information from two or more 24-hour recalls using correlated mixed model regression. The model allows for correlation between the probability of consuming a food on a single day and the consumption-day amount. Percentiles of the distribution of usual intake are computed from the estimated model parameters. RESULTS: The Eating at America's Table Study data are used to illustrate the method to estimate the distribution of usual intake for whole grains and dark-green vegetables for men and women and the distribution of usual intakes of whole grains by educational level among men. A simulation study indicates that the NCI method leads to substantial improvement over existing methods for estimating the distribution of usual intake of foods. CONCLUSIONS: The NCI method provides distinct advantages over previously proposed methods by accounting for the correlation between probability of consumption and amount consumed and by incorporating covariate information. Researchers interested in estimating the distribution of usual intakes of foods for a population or subpopulation are advised to work with a statistician and incorporate the NCI method in analyses.
Analysis of Variance↗
Statistical methods for estimating usual intake of nutrients and foods: a review of the theory.
Although 24-hour recalls are frequently used in dietary assessment, intake on a single day is a poor estimator of long-term usual intake. Statistical modeling mitigates this limitation more effectively than averaging multiple 24-hour recalls per respondent. In this article, we describe the statistical theory that underlies the four major modeling methods developed to date, then review the strengths and limitations of each method. We focus on the problem of estimating the distribution of usual intake for a population from 24-hour recall data, giving special attention to the problems inherent in modeling usual intake for foods or food groups that a proportion of the population does not consume every day (ie, episodically consumed foods). All four statistical methods share a common framework. Differences between the methods arise from different assumptions about the measurement characteristics of 24-hour recalls and from the fact that more recently developed methods build upon their predecessor(s). These differences can result in estimated usual intake distributions that differ from one another. We also demonstrate the need for an improved method for estimating usual intake distributions for episodically consumed foods.
Data Interpretation, Statistical↗
Demographic, HIV risk behavior, and health status characteristics of "crack" cocaine injectors compared to other injection drug users in three New England cities.
OBJECTIVES: To compare demographic, HIV risk behaviors, and health status characteristics of injection drug users (IDUs) who have injected "crack" cocaine with IDUs who have not. METHODS: Nine hundred and eighty-nine IDUs were recruited in New Haven, CT, Hartford, CT and Springfield, MA from January 2000 to May 2002. Participants were administered a modified version of the National Institute on Drug Abuse Risk Behavior Assessment Questionnaire. RESULTS: Nine percent (n = 89) of participants reported "ever" injecting crack cocaine and 4.2% (n = 42) reported injecting crack in the past 30 days. Lifetime and current crack injectors did not differ significantly on any demographic characteristics. Lifetime and current crack injectors did not differ on gender, age or marital status from IDUs who have never injected crack. Significant differences were found on race, education, employment and residence, with crack injectors more likely to be white, employed, better educated and living in New Haven than IDUs who have never injected crack. After adjusting for current (past 30 day) speedball and powder cocaine injection, crack injectors reported higher rates of risky drug use behaviors and female crack injectors reported higher rates of risky sexual behaviors. Crack injectors reported higher rates of abscesses, mental illness and Hepatitis C infection, but not Hepatitis B or HIV infection. CONCLUSIONS: The emergence of crack cocaine injection requires urgent attention, as this new drug use behavior is associated with elevated rates of high risk behaviors.
Adult↗
Psychosocial predictors of energy underreporting in a large doubly labeled water study.
BACKGROUND: Underreporting of energy intake is associated with self-reported diet measures and appears to be selective according to personal characteristics. Doubly labeled water is an unbiased reference biomarker for energy intake that may be used to assess underreporting. OBJECTIVE: Our objective was to determine which factors are associated with underreporting of energy intake on food-frequency questionnaires (FFQs) and 24-h dietary recalls (24HRs). DESIGN: The study participants were 484 men and women aged 40-69 y who resided in Montgomery County, MD. Using the doubly labeled water method to measure total energy expenditure, we considered numerous psychosocial, lifestyle, and sociodemographic factors in multiple logistic regression models for prediction of the probability of underreporting on the FFQ and 24HR. RESULTS: In the FFQ models, fear of negative evaluation, weight-loss history, and percentage of energy from fat were the best predictors of underreporting in women (R(2) = 0.09); body mass index, comparison of activity level with that of others of the same sex and age, and eating frequency were the best predictors in men (R(2) = 0.10). In the 24HR models, social desirability, fear of negative evaluation, body mass index, percentage of energy from fat, usual activity, and variability in number of meals per day were the best predictors of underreporting in women (R(2) = 0.22); social desirability, dietary restraint, body mass index, eating frequency, dieting history, and education were the best predictors in men (R(2) = 0.25). CONCLUSION: Although the final models were significantly related to underreporting on both the FFQ and the 24HR, the amount of variation explained by these models was relatively low, especially for the FFQ.
Adult↗
Smoking status identification: two managed care organizations' experiences with a pilot project to implement identification systems in independent practice associations.
OBJECTIVE: To determine whether managed care organizations (MCOs) can effectively promote the sustained use of smoking status identification systems among independent practice associations. STUDY DESIGN: Quasi-experimental design measuring smoking status documentation before and after an intervention. METHODS: A chart review of the MCOs' patients at 4 participating primary care clinics determined the baseline for smoking status documentation before intervention. Baseline data were unavailable from a fifth participating clinic. Two quality improvement personnel were sent by the MCOs to help the clinics chose and implement a system for identifying smoking status. All of the clinics chose a sticker system. The change in smoking status documentation was assessed by chart reviews of patients enrolled in the MCOs who were seen during the period between 3 and 16 months after implementation of the system. RESULTS: Following the intervention, a significant increase in smoking status documentation was noted among participating clinics. The proportion of patients whose smoking status was identified and documented by any method increased from 50% to 87% (P < .01) at the 4 clinics with baseline data. By clinic, the increase varied from 6% to 60%. The sticker system was the method by which most patients' smoking status was documented (77%). There were no controls, so the influence of outside factors, including a regional smoking cessation campaign that coincided with this study, cannot be quantified. CONCLUSIONS: Managed care organizations may be an effective change agent for implementing the guidelines for tobacco use and dependence treatment.
Blue Cross Blue Shield Insurance Plans↗
Analysis of repeated measures data with clumping at zero.
Longitudinal or repeated measures data with clumping at zero occur in many applications in biometrics, including health policy research, epidemiology, nutrition, and meteorology. These data exhibit correlation because they are measured on the same subject over time or because subjects may be considered repeated measures within a larger unit such as a family. They present special challenges because of the extreme non-normality of the distributions involved. A model for repeated measures data with clumping at zero, using a mixed-effects mixed-distribution model with correlated random effects, is presented. The model contains components to model the probability of a nonzero value and the mean of nonzero values, allowing for repeated measurements using random effects and allowing for correlation between the two components. Methods for describing the effect of predictor variables on the probability of nonzero values, on the mean of nonzero values, and on the overall mean amount are given. This interpretation also applies to the mixed-distribution model for cross-sectional data. The proposed methods are illustrated with analyses of effects of several covariates on medical expenditures in 1996 for subjects clustered within households using data from the Medical Expenditure Panel Survey.
Biometry↗