Influences of breath sample re-use on the accuracy of lung cancer detection dogs.

Evaluations of dogs as lung cancer detectors using breath samples have produced a variety of results, some quite promising. Breath samples are typically collected onto a substrate and stored in a sealed container when not in use, but volatile compounds dissipate when the substrate is exposed during training and evaluation sessions. Collection of appropriate samples for training and testing dogs requires significant resources and strict control of recruitment and sample collection processes. Therefore, some researchers re-use samples while training dogs. No systematic evaluation of the effect of sample re-use on dogs' training performance has been conducted, so the influence of this potentially important training factor is not known. We trained seven dogs to indicate the presence of lung cancer positive breath samples using an automated apparatus. The samples were stored at -60 °C or -80 °C. Samples from 460 individuals who were classified as positive or negative for lung cancer were used for training samples. Individual samples were presented to dogs up to four times over a period of 2 years. As sample re-use increased, sensitivity declined (-6.65,p= < .001, 95% CI [-10.56, -2.76]), specificity increased (2.87,p= .036, 95% CI [.19, 5.55]), and the dogs' bias shifted in the direction of a negative indication bias (-.094,p= < .001, 95% CI [-.149, -.39]). However, there were no significant changes in the measure associated with the detectability of the target (-0.30,p= .285, 95% CI [-.087, .26]). All observed changes in performance across sample re-use were small. Therefore, these findings suggest that sample re-use may be appropriate for training, but additional research is required to determine which factors underly changes in performance as breath samples are re-used.

Associations of abdominal muscle area and density with coronary artery calcium volume and density: The multi-ethnic study of atherosclerosis.

BACKGROUND: Due to the opposing cardiovascular risk profiles of CAC volume and density, we tested the hypothesis that increased abdominal muscle area (AMA) and density (AMD) were significantly associated with lower coronary arterial calcium (CAC) volume and higher CAC density. METHODS: Using data from 787 participants from the Multi-Ethnic Study of Atherosclerosis, Ancillary Body Composition Study, we analyzed abdominal and chest computed tomography (CT) scans. Abdominal scans were scored for muscle area, muscle density (attenuation) and visceral and subcutaneous fat. Chest scans were scored for CAC volume and Agatston values, which were used to derive CAC density scores. RESULTS: The mean (SD) age and BMI of the participants was 67.8 (9.0) years and 27.9 (4.8) kg/m2, respectively. Forty-one percent were female, 46% were Caucasian, 60% had hypertension, 17% had diabetes, and 46% had dyslipidemia. AMA was positively associated with CAC volume (p < .001) and inversely associated with CAC density (p < .001). Conversely, AMD was inversely associated with CAC volume and positively associated with CAC density in minimally adjusted models (p < .001), but not significant in confounder adjusted models. CONCLUSION: AMA and AMD had differing associations with CAC volume and density, with AMA significantly associated with a higher risk CAC profile (high volume, low density) and AMD not significantly associated with CAC volume or density. Future research needs to account for the unique components of both muscle composition and CAC.

Prevention of Type 2 Diabetes in U.S. Hispanic Youth: A Systematic Review of Lifestyle Interventions.

CONTEXT: Prevalence of type 2 diabetes mellitus (T2DM) in youth has increased rapidly in recent decades along with rises in childhood obesity. Disparities in risk and prevalence of T2DM are evident in Hispanic youth when compared with non-Hispanic whites. Targeted diabetes prevention programs have been recommended to reduce risk prior to adulthood in this population. This systematic review explores the effectiveness of lifestyle-based diabetes prevention interventions for Hispanic youth. EVIDENCE ACQUISITION: PubMed, PsycINFO, Web of Science, and CENTRAL were searched from database inception to March 1, 2017, for studies that evaluated lifestyle-focused prevention trials targeting U.S. Hispanic youth under age 18 years. Fifteen publications met criteria for inclusion. EVIDENCE SYNTHESIS: Of the 15 studies, 11 were RCTs; four were uncontrolled. Interventions were heterogeneous in intensity, content, and setting. Duration of most trials was 12-16 weeks. Mean age of participants ranged from 9.8 to 15.8 years, sample sizes were generally small, and the majority of participants were overweight (BMI ≥85th percentile). Three studies reported statistically significant reductions in mean BMI, four in BMI z-score, and six in fasting glucose/insulin. Study quality was moderate to high. Effect sizes were generally small to medium. CONCLUSIONS: Evidence for the impact of lifestyle-based diabetes prevention interventions targeting U.S. Hispanic youth remains limited. Few interventions demonstrated success in reducing BMI and glucose regulation and follow-up times were brief. More studies are needed that recruit larger samples sizes, extend follow-up times, explore innovative delivery modalities, and examine effectiveness across sex and age.

Type II diabetes disparities in diverse women: the potential roles of body composition, diet and physical activity.

The rates of diabetes in the USA are rapidly increasing, and vary widely across different racial/ethnic groups. This paper explores the potential contribution of body composition, diet and physical activity in explaining diabetes disparities across women of different racial and ethnic backgrounds. For body composition, racial/ethnic groups differ widely by BMI, distribution of body mass and quantity and type of adipose tissue. Dietary patterns that vary across race/ethnicity include consumption of meat, added sugars, high-glycemic carbohydrates and fast food. Additionally, physical activity patterns of interest include aerobic versus muscle-strengthening exercises, and the purpose of physical activity (leisure, occupation, or transportation). Overall, these variables provide a partial picture of the source of these widening disparities, and could help guide future research in addressing and reducing diabetes disparities.