Assessing Dietary Outcomes in Intervention Studies: Pitfalls, Strategies, and Research Needs.

To inform strategies to improve the dietary intakes of populations, robust evaluations of interventions are required. This paper is drawn from a workshop held at the International Society of Behavioral Nutrition and Physical Activity 2017 Annual Meeting, and highlights considerations and research priorities relevant to measuring dietary outcomes within intervention studies. Self-reported dietary data are typically relied upon in such studies, and it is recognized that these data are affected by random and systematic error. Additionally, differential error between intervention and comparison groups or pre- and post-intervention can be elicited by the intervention itself, for example, by creating greater awareness of eating or drinking occasions or the desire to appear compliant. Differential reporting can render the results of trials incorrect or inconclusive by leading to biased estimates and reduced statistical power. The development of strategies to address intervention-related biases requires developing a better understanding of the situations and population groups in which interventions are likely to elicit differential reporting and the extent of the bias. Also needed are efforts to expand the feasibility and applications of biomarkers to address intervention-related biases. In the meantime, researchers are encouraged to consider the potential for differential biases in dietary reporting in a given study, to choose tools carefully and take steps to minimize and/or measure factors such as social desirability biases that might contribute to differential reporting, and to consider the implications of differential reporting for study results

Variable selection with FDR control for noisy data -- an application to screening metabolites that are associated with breast and colorectal cancer

The rapidly expanding field of metabolomics presents an invaluable resource for understanding the associations between metabolites and various diseases. However, the high dimensionality, presence of missing values, and measurement errors associated with metabolomics data can present challenges in developing reliable and reproducible methodologies for disease association studies. Therefore, there is a compelling need to develop robust statistical methods that can navigate these complexities to achieve reliable and reproducible disease association studies. In this paper, we focus on developing such a methodology with an emphasis on controlling the False Discovery Rate during the screening of mutual metabolomic signals for multiple disease outcomes. We illustrate the versatility and performance of this procedure in a variety of scenarios, dealing with missing data and measurement errors. As a specific application of this novel methodology, we target two of the most prevalent cancers among US women: breast cancer and colorectal cancer. By applying our method to the Wome's Health Initiative data, we successfully identify metabolites that are associated with either or both of these cancers, demonstrating the practical utility and potential of our method in identifying consistent risk factors and understanding shared mechanisms between diseases

Child height gain is associated with consumption of animal-source foods in livestock-owning households in Western Kenya

OBJECTIVE: To clarify the pathways between household livestock and child growth by assessing the relationships between consumption of animal-source foods (ASF) and child growth and evaluating the household livestock correlates of child consumption of ASF. DESIGN: We conducted a longitudinal cohort study of anthropometry and 3 d feeding recalls among children <5 years old between June 2014 and May 2015. In addition, we collected data on wealth, livestock ownership and livestock diseases in the same households. We used linear and negative binomial mixed models to evaluate the relationships between household livestock characteristics, reported consumption of ASF and child growth. SETTING: An 1800-household surveillance catchment area in Western Kenya within the structure of human and animal health surveillance systems. SUBJECTS: Children (n 874) <5 years old. RESULTS: Among children >6 months old, reported frequency of egg and milk consumption was associated with increased monthly height gain (for each additional report of consumption over 3 d: adjusted β (95% CI) = 0·010 (0·002, 0·019) cm/month and 0·008 (0·004, 0·013) cm/month, respectively). Poultry ownership was associated with higher reported frequency of egg, milk and chicken consumption (adjusted incidence rate ratio (95% CI) = 1·3 (1·2, 1·4), 1·4 (1·1, 1·6) and 1·3 (1·1, 1·4), respectively). Some livestock diseases were associated with lower reported frequency of ASF intake (livestock digestive Child growth diseases-adjusted incidence rate ratio (95% CI) = 0·89 (0·78, 1·00)). CONCLUSIONS: Child height gain was associated with milk and egg consumption in this cohort. ASF consumption was related to both household livestock ownership and animal health

Eating Pattern Response to a Low-Fat Diet Intervention and Cardiovascular Outcomes in Normotensive Women: The Women's Health Initiative.

BackgroundWomen without cardiovascular disease (CVD) or hypertension at baseline assigned to intervention in the Women's Health Initiative Dietary Modification (DM) trial experienced 30% lower risk of coronary heart disease (CHD), whereas results in women with hypertension or prior CVD could have been confounded by postrandomization use of statins.ObjectivesIntervention participants reported various self-selected changes to achieve the 20% total fat goals. Reviewed are intervention compared with comparison group HRs for CHD, stroke, and total CVD in relation to specific dietary changes in normotensive participants.MethodsDietary change was assessed by comparing baseline with year 1 FFQ data in women (n&nbsp;=&nbsp;10,371) without hypertension or CVD at baseline with intake of total fat above the median to minimize biases due to use of the FFQ in trial eligibility screening.ResultsIntervention participants self-reported compensating reduced energy intake from total fat by increasing carbohydrate and protein. Specifically they increased plant protein, with those in the upper quartile (increased total protein by ≥3.3% of energy) having a CHD HR of 0.39 (95% CI: 0.22, 0.71), compared with 0.92 (95% CI: 0.57, 1.48) for those in the lower quartile of change (decreased total protein ≥0.6% of energy), with P-trend of 0.04. CHD HR did not vary significantly with change in percentage energy from carbohydrate, and stroke HR did not vary significantly with any macronutrient changes. Scores reflecting adherence to recommended dietary patterns including the Dietary Approaches to Stop Hypertension Trial and the Healthy Eating Index showed favorable changes in the intervention group.ConclusionsIntervention group total fat reduction replaced with increased carbohydrate and some protein, especially plant-based protein, was related to lower CHD risk in normotensive women without CVD who reported high baseline total fat intake. This trial was registered at clinicaltrials.gov as NCT00000611. Link to the WHI trial protocol: https://www.whi.org/about/SitePages/Dietary%20Trial.aspx

Use of complementary and alternative medicine and breast cancer survival in the Health, Eating, Activity, and Lifestyle Study

PURPOSE: Use of complementary and alternative medicine (CAM) is common among breast cancer patients, but less is known about whether CAM influences breast cancer survival. METHODS: Health Eating, Activity, and Lifestyle (HEAL) Study participants (n = 707) were diagnosed with stage I-IIIA breast cancer. Participants completed a 30-month post-diagnosis interview including questions on CAM use (natural products such as dietary and botanical supplements, alternative health practices, and alternative medical systems), weight, physical activity, and comorbidities. Outcomes were breast cancer-specific and total mortality, which were ascertained from the Surveillance Epidemiology and End Results registries in Western Washington, Los Angeles County, and New Mexico. Cox proportional hazards regression models were fit to data to estimate hazard ratios (HR) and 95 % confidence intervals (CI) for mortality. Models were adjusted for potential confounding by sociodemographic, health, and cancer-related factors. RESULTS: Among 707 participants, 70 breast cancer-specific deaths and 149 total deaths were reported. 60.2 % of participants reported CAM use post-diagnosis. The most common CAM were natural products (51 %) including plant-based estrogenic supplements (42 %). Manipulative and body-based practices and alternative medical systems were used by 27 and 13 % of participants, respectively. No associations were observed between CAM use and breast cancer-specific (HR 1.04, 95 % CI 0.61-1.76) or total mortality (HR 0.91, 95 % CI 0.63-1.29). CONCLUSION: Complementary and alternative medicine use was not associated with breast cancer-specific mortality or total mortality. Randomized controlled trials may be needed to definitively test whether there is harm or benefit from the types of CAM assessed in HEAL in relation to mortality outcomes in breast cancer survivors

Reliability Estimates For assessing Meal Timing Derived From Longitudinal Repeated 24-Hour Dietary Recalls

BACKGROUND: Regulating meal timing may have efficacy for improving metabolic health for preventing or managing chronic disease. However, the reliability of measuring meal timing with commonly used dietary assessment tools needs characterization prior to investigating meal timing and health outcomes in epidemiologic studies. OBJECTIVES: to evaluate the reliability of estimating meal timing parameters, including overnight fasting duration, the midpoint of overnight fasting time, the number of daily eating episodes, the period with the largest percentage of daily caloric intake, and late last eating episode (\u3e 09:00 pm) from repeated 24-h dietary recalls (24HRs). METHODS: Intraclass correlation coefficients (ICC), Light\u27s Kappa estimates, and 95% CIs were calculated from repeated 24HR administered in 3 epidemiologic studies: The United States-based Interactive Diet and Activity Tracking in AARP (IDATA) study (n = 996, 6 24HR collected over 12-mo), German EPIC-Potsdam Validation Study (European Prospective Investigation into Cancer and Nutrition Potsdam Germany cohort) (n = 134, 12 24HR collected over 12-mo) and EPIC-Potsdam BMBF-II Study (Federal Ministry of Education and Research, Bundesministerium für Bildung und Forschung ) (n = 725, 4 24HR collected over 36 mo). RESULTS: Measurement reliability of overnight fasting duration based on a single 24HR was poor in all studies [ICC range: 0.27; 95% CI: 0.23, 0.32 - 0.46; 95% CI: 0.43, 0.50]. Reliability was moderate with 3 24HR (ICC range: 0.53; 95% CI: 0.47, 0.58 in IDATA, 0.62; 95% CI: 0.52, 0.69 in the EPIC-Potsdam Validation Study, and 0.72; 95% CI: 0.70-0.75 in the EPIC-Potsdam BMBF-II Study). Results were similar for the midpoint of overnight fasting time and the number of eating episodes. Reliability of measuring late eating was fair in IDATA (Light\u27s Kappa: 0.30; 95% CI: 0.21, 0.39) and slight in the EPIC-Potsdam Validation study and the EPIC-Potsdam BMBF-II study (Light\u27s Kappa: 0.19; 95% CI: 0.15, 0.25 and 0.09; 95% CI: 0.06, 0.12, respectively). Reliability estimates differed by sex, BMI, weekday, and season of 24HR administration in some studies. CONCLUSIONS: Our results show that ≥ 3 24HR over a 1-3-y period are required for reliable estimates of meal timing variables

Gene-environment interactions and obesity traits among postmenopausal African-American and Hispanic women in the Women’s Health Initiative SHARe Study

Genome-wide association studies of obesity measures have identified associations with single nucleotide polymorphisms (SNPs). However, no large-scale evaluation of gene-environment interactions has been performed. We conducted a search of gene-environment (G×E) interactions in post-menopausal African-American and Hispanic women from the Women’s Health Initiative SNP Health Association Resource GWAS study. Single SNP linear regression on body mass index (BMI) and waist-to-hip circumference ratio (WHR) adjusted for multidimensional-scaling-derived axes of ancestry and age was run in race-stratified data with 871,512 SNPs available from African-Americans (N=8,203) and 786,776 SNPs from Hispanics (N=3,484). Tests of G×E interaction at all SNPs for recreational physical activity (met-hrs/wk), dietary energy intake (kcal/day), alcohol intake (categorical), cigarette smoking years, and cigarette smoking (ever vs. never) were run in African-Americans and Hispanics adjusted for ancestry and age at interview, followed by meta-analysis of G×E interaction terms. The strongest evidence for concordant G×E interactions in African-Americans and Hispanics was for smoking and marker rs10133840 (Q statistic P=0.70, beta=−0.01, P=3.81×10−7) with BMI as the outcome. The strongest evidence for G×E interaction within a cohort was in African-Americans with WHR as outcome for dietary energy intake and rs9557704 (SNP×kcal =−0.04, P=2.17×10−7). No results exceeded the Bonferroni–corrected statistical significance threshold