Physiological assessment of a 16 day, 4385 km ultra-endurance mountain bike race: A case study.

The Tour Divide (TD) is a 4385 km ultra-endurance bicycle race that follows the continental divide from Canada to Mexico. In this case study, we performed a comprehensive molecular and physiological profile before and after the completion of the TD. Assessments were performed 35 days before the start (Pre-TD) and ∼36 h after the finish (Post-TD). Total energy expenditure was assessed during the first 9 days by doubly labelled water (2 H2 18 O), abdominal and leg tissue volumes via MRI, and graded exercise tests to quantify fitness and substrate preference. Vastus lateralis muscle biopsies were taken to measure mitochondrial function via respirometry, and vascular function was assessed using Doppler ultrasound. The 47-year-old male subject took 16 days 7 h 45 min to complete the route. He rode an average of 16.8 h/day. Neither maximal O2 uptake nor maximal power output changed pre- to post-TD. Measurement of total energy expenditure and dietary recall records suggested maintenance of energy balance, which was supported by the lack of change in body weight. The subject lost both appendicular and trunk fat mass and gained leg lean mass pre- to post-TD. Skeletal muscle mitochondrial and vascular endothelial function decreased pre- to post-TD. Overall, exercise performance was maintained despite reductions in muscle mitochondrial and vascular endothelial function post-TD, suggesting a metabolic reserve in our highly trained athlete.

Does Aerobic Exercise Increase Skeletal Muscle Mass in Female and Male Adults?

INTRODUCTION: It is uncertain whether aerobic exercise in the form of walking contributes to the preservation or increase in total or regional skeletal muscle mass (SMM). PURPOSE: This study aimed to determine the effects of aerobic exercise on total and regional (upper body verses leg SMM) in male ( n = 105) and female ( n = 133) adults with overweight and obesity. METHODS: A retrospective analysis of data from four randomized controlled trials. Participants included those who completed the given trial (control, n = 63; intervention, n = 175) and with complete magnetic resonance imaging (MRI) measured adipose tissue and SMM pre- and postintervention. Macronutrient intake was assessed for a subsample of participants. Supervised exercise was performed by walking on a treadmill for durations ranging from 12 to 24 wk at intensities between 50% and 75% of V̇O 2peak . RESULTS: All MRI-measured adipose tissue depots were reduced, and cardiorespiratory fitness was increased by aerobic exercise compared with controls ( P < 0.001). Independent of baseline SMM, aerobic exercise was associated with a small reduction (estimated mean difference ± standard error) in whole-body SMM (-0.310 ± 0.150 kg, P = 0.039) and upper body SMM (-0.273 ± 0.121 kg, P = 0.025) compared with control. No between-group difference was observed for change in leg SMM ( P > 0.10). A negative association was observed between the relative change in body weight and change in total ( R2 = 0.37, P < 0.001), upper body ( R2 = 0.21, P < 0.001), and leg SMM ( R2 = 0.09, P = 0.701). The SMM-to-adipose tissue ratio increased in response to aerobic exercise and was positively associated with weight loss ( P < 0.001). Change in SMM was not associated with dietary protein intake ( P > 0.10). CONCLUSIONS: Aerobic exercise performed while walking preserves, but does not increase, SMM in exercising muscle of adults. SMM not directly targeted by aerobic exercise may not be maintained.

The Effects of a High-Carbohydrate versus a High-Fat Shake on Biomarkers of Metabolism and Glycemic Control When Used to Interrupt a 38-h Fast: A Randomized Crossover Study.

This study aimed to determine the impact of various fast-interrupting shakes on markers of glycemic control including glucose, ß-hydroxybutyrate (BHB), insulin, glucagon, GLP-1, and GIP. Twenty-seven sedentary adults (twelve female, fifteen male) with overweight or obesity completed this study. One condition consisted of a 38-h water-only fast, and the other two conditions repeated this, but the fasts were interrupted at 24 h by either a high carbohydrate/low fat (HC/LF) shake or an isovolumetric and isocaloric low carbohydrate/high fat (LC/HF) shake. The water-only fast resulted in 135.3% more BHB compared to the HC/LF condition (p < 0.01) and 69.6% more compared to the LC/HF condition (p < 0.01). The LC/HF condition exhibited a 38.8% higher BHB level than the HC/LF condition (p < 0.01). The area under the curve for glucose was 14.2% higher in the HC/LF condition than in the water condition (p < 0.01) and 6.9% higher compared to the LC/HF condition (p < 0.01), with the LC/HF condition yielding 7.8% more glucose than the water condition (p < 0.01). At the 25-h mark, insulin and glucose-dependent insulinotropic polypeptide (GIP) were significantly elevated in the HC/LF condition compared to the LC/HF condition (p < 0.01 and p = 0.02, respectively) and compared to the water condition (p < 0.01). Furthermore, insulin, GLP-1, and GIP were increased in the LC/HF condition compared to the water condition at 25 h (p < 0.01, p = 0.015, and p < 0.01, respectively). By the 38-h time point, no differences were observed among the conditions for any of the analyzed hormones. While a LC/HF shake does not mimic a fast completely, it does preserve some of the metabolic changes including elevated BHB and glucagon, and decreased glucose and insulin compared to a HC/LF shake, implying a potential for improved metabolic health.

Non-Destructive Monitoring of Foliar Fungicide Efficacy with Hyperspectral Sensing in Grapevine.

Frequent fungicide applications are required to manage grapevine powdery mildew (Erysiphe necator). However, this practice is costly and has led to widespread fungicide resistance. A method of monitoring in-field fungicide efficacy could help growers maximize spray-interval length, thereby reducing costs and the rate of fungicide resistance emergence. The goal of this study was to evaluate if hyperspectral sensing in the visible to shortwave infrared range (400 to 2,400 nm) can quantify foliar fungicide efficacy on grape leaves. Commercial formulations of metrafenone, Bacillus mycoides isolate J (BmJ), and sulfur were applied on Chardonnay grapevines in vineyard or greenhouse settings. Foliar reflectance was measured with handheld hyperspectral spectroradiometers at multiple days post-application. Fungicide efficacy was estimated as a proxy for fungicide residue and disease control measured with the Blackbird microscopy imaging robot. Treatments could be differentiated from the untreated control with an accuracy of 73.06% for metrafenone, 67.76% for BmJ, and 94.10% for sulfur. The change in spectral reflectance was moderately correlated with the cube root of the area under the disease progress curve for metrafenone- and sulfur-treated samples (R2 = 0.38 and 0.36, respectively) and with sulfur residue (R2 = 0.42). BmJ treatment impacted foliar physiology by enhancing the leaf mass/area and reducing the nitrogen and total phenolic content as estimated from spectral reflectance. The results suggest that hyperspectral sensing can be used to monitor in-situ fungicide efficacy, and the prediction accuracy depends on the fungicide and the time point measured. The ability to monitor in-situ fungicide efficacy could facilitate more strategic fungicide applications and promote sustainable grapevine protection. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Time Spent Jogging/Running and Biological Aging in 4458 U.S. Adults: An NHANES Investigation.

Telomere length is a good index of cellular aging. Longer telomeres are predictive of longer life, and healthy lifestyles are associated with longer telomeres. This study explored the relationship between time spent jogging or running each week and leukocyte telomere length (LTL) in 4458 randomly selected U.S. adults. The association was studied using data collected by the National Health and Nutrition Examination Survey (NHANES), and a cross-sectional design. Total weekly jog/run time was calculated from survey responses. From the minute totals, three categories were formed: <10 min/week, 10-74 min/week, and ≥75 min/week. Adults in the third category met the U.S. guidelines. Data were analyzed using one-way ANOVA. Partial correlation was used to adjust for differences in potential mediating factors, including demographic and lifestyle/medical factors. In the total sample, after adjusting for all the potential covariates, mean LTL significantly differed across the three jog/run categories (F = 4.1, p = 0.0272). Specifically, adults who met the guidelines via jogging and/or running had significantly longer telomeres than adults who performed no jogging/running. Adults in the middle category did not differ from the other two categories. A minimum of 75 min of jogging/running weekly is predictive of longer telomeres when compared to adults who do not jog or run regularly.

Long-term cancer outcomes after bariatric surgery.

OBJECTIVE: Obesity is associated with increased cancer risk. Because of the substantial and sustained weight loss following bariatric surgery, postsurgical patients are ideal to study the association of weight loss and cancer. METHODS: Retrospectively (1982-2019), 21,837 bariatric surgery patients (surgery, 1982-2018) were matched 1:1 by age, sex, and BMI with a nonsurgical comparison group. Procedures included gastric bypass, gastric banding, sleeve gastrectomy, and duodenal switch. Primary outcomes included cancer incidence and mortality, stratified by obesity- and non-obesity-related cancers, sex, cancer stage, and procedure. RESULTS: Bariatric surgery patients had a 25% lower risk of developing any cancers compared with a nonsurgical comparison group (hazard ratio [HR] 0.75; 95% CI 0.69-0.81; p < 0.001). Cancer incidence was lower among female (HR 0.67; 95% CI 0.62-0.74; p < 0.001) but not male surgery patients, with the HR lower for females than for males (p < 0.001). Female surgery patients had a 41% lower risk for obesity-related cancers (i.e., breast, ovarian, uterine, and colon) compared with nonsurgical females (HR 0.59; 95% CI 0.52-0.66; p < 0.001). Cancer mortality was significantly lower after surgery in females (HR 0.53; 95% CI 0.44-0.64; p < 0.001). CONCLUSIONS: Bariatric surgery was associated with lower all-cancer and obesity-related cancer incidence among female patients. Cancer mortality was significantly lower among females in the surgical group versus the nonsurgical group.

Relationship between Sitting Time and Insulin Resistance in 6931 U.S. Adults: The Mediating Role of Abdominal Adiposity.

This cross-sectional investigation examined the relationship between sitting time and insulin resistance in 6931 U.S. adults. The mediating effects of several covariates were evaluated. Self-reported sitting time, measured in minutes per day, was the exposure variable. Insulin resistance (IR), indexed using the natural log of the homeostatic model assessment of insulin resistance (L-HOMA-IR), was the outcome variable. This study used data collected from the 2011-2018 National Health and Nutrition Examination Survey (NHANES). Results showed a strong, positive, dose-response association between sitting time and insulin resistance after adjusting for age, sex, race, and year of assessment (F = 12.6, p < 0.0001). Across the sitting time tertiles (low, moderate, and high), the L-HOMA-IR means (±SE) each differed from each other (0.37 ± 0.008, 0.40 ± 0.012, and 0.43 ± 0.012). Further controlling for cigarette smoking and physical activity did not alter the significance of the relationship. Adding body mass index (BMI) to the demographic covariates weakened the relationship, but it remained significant. However, the association was no longer significant after adjusting for the demographic covariates and waist circumference (F = 1.1, p = 0.3349). None of the L-HOMA-IR means (±SE) differed from each other (0.40 ± 0.007, 0.41 ± 0.009, and 0.41 ± 0.008). Overall, waist circumference was a powerful mediating variable between sitting time and insulin resistance. Apparently, time spent sitting is a powerful predictor of IR. However, much of the association between sitting time and IR is a function of differences in waist size. As a strong measure of abdominal adiposity and a significant predictor of multiple metabolic diseases, managing waist size is a health practice to consider when insulin resistance is a concern.

The Effects of Exercise on Appetite-Regulating Hormone Concentrations over a 36-h Fast in Healthy Young Adults: A Randomized Crossover Study.

Hunger and satiety are controlled by several physiological mechanisms, including pancreatic and gastrointestinal hormones. While the influence of exercise and fasting have been described individually, in relation to these hormones, there is a paucity of work showing the effects of the two modalities (fasting and exercise) combined. Twenty healthy adults (11 males, 9 females) completed both conditions of this study, each consisting of a 36-h water-only fast. One of the fasts began with treadmill exercise, and the differences between the conditions on various appetite hormones were measured every 12 h. The difference in the area under the curve between conditions for ghrelin was 211.8 ± 73.1 pg/mL (F = 8.40, p < 0.0105), and, for GLP-1, it was -1867.9 ± 850.4 pg/mL (F = 4.82, p < 0.0422). No significant differences were noted for areas under the curve between conditions for leptin, PP, PYY, insulin, or GIP. Initiating a fast with exercise lowers ghrelin concentrations and elevates GLP-1 concentrations. Given that ghrelin elicits feelings of hunger and GLP-1 signals feelings of satiety, adding exercise to the beginning of a fast may reduce some of the biological drive of hunger, which could make fasting more tolerable, leading to better adherence and more significant health outcomes.

Long-term all-cause and cause-specific mortality for four bariatric surgery procedures.

OBJECTIVE: This retrospective study incorporated long-term mortality results after different bariatric surgery procedures and for multiple age at surgery groups. METHODS: Participants with bariatric surgery (surgery) and without (non-surgery) were matched (1:1) for age, sex, BMI, and surgery date with a driver license application/renewal date. Mortality rates were compared by Cox regression, stratified by sex, surgery type, and age at surgery. RESULTS: Participants included 21,837 matched surgery and non-surgery pairs. Follow-up was up to 40 years (mean [SD], 13.2 [9.5] years). All-cause mortality was 16% lower in surgery compared with non-surgery groups (hazard ratio, 0.84; 95% CI: 0.79-0.90; p < 0.001). Significantly lower mortality after bariatric surgery was observed for both females and males. Mortality after surgery versus non-surgery decreased significantly by 29%, 43%, and 72% for cardiovascular disease, cancer, and diabetes, respectively. The hazard ratio for suicide was 2.4 times higher in surgery compared with non-surgery participants (95% CI: 1.57-3.68; p < 0.001), primarily in participants with ages at surgery between 18 and 34 years. CONCLUSIONS: Reduced all-cause mortality was durable for multiple decades, for multiple bariatric surgical procedures, for females and males, and for greater than age 34 years at surgery. Rate of death from suicide was significantly higher in surgery versus non-surgery participants only in the youngest age at surgery participants.

Milk-Fat Intake and Differences in Abdominal Adiposity and BMI: Evidence Based on 13,544 Randomly-Selected Adults.

The primary purpose of this investigation was to evaluate the relationship between milk-fat intake and obesity, particularly abdominal obesity, in 13,544 U.S. adults. A lesser objective was to measure the degree to which the association was influenced by multiple potential confounding variables. This cross-sectional study used data from the 2011-2016 National Health and Nutrition Examination Survey (NHANES). Quantity of milk-fat regularly consumed was the exposure variable. Sagittal abdominal diameter (SAD), a measure of abdominal obesity, and body mass index (BMI) were the outcome variables. Sagittal abdominal diameter is a strong predictor of visceral abdominal fat, when measured by computed tomography, and has been shown to predict cardiometabolic disorders better than BMI. After controlling for age, race, gender, physical activity, leisure computer use and gaming, alcohol habits, and cigarette use, significantly lower BMIs were associated with consistent non-fat and full-fat milk consumption (F = 4.1, p = 0.0063). A significantly lower SAD was associated only with regular consumption of non-fat milk (F = 5.0, p = 0.0019). No significant differences were detected between the other milk-fat groups or milk abstainers. In this nationally representative sample, only 19.6% of adults regularly consumed low-fat milk. In conclusion, consistent non-fat milk intake was predictive of lower levels of abdominal adiposity compared to consumption of higher levels of milk-fat.

A Comprehensive Characterization of Ecological and Epidemiological Factors Driving Perennation of Podosphaera macularis Chasmothecia on Hop (Humulus lupulus).

Hop powdery mildew, caused by the ascomycete fungus Podosphaera macularis, is a consistent threat to sustainable hop production. The pathogen utilizes two reproductive strategies for overwintering and perennation: (i) asexual vegetative hyphae on dormant buds that emerge the following season as infected shoots; and (ii) sexual ascocarps (chasmothecia), which are discharged during spring rain events. We demonstrate that P. macularis chasmothecia, in the absence of any asexual P. macularis growth forms, are a viable overwintering source capable of causing early season infection two to three orders of magnitude greater than that reported for perennation via asexual growth. Two epidemiological models were defined that describe (i) temperature-driven maturation of P. macularis chasmothecia; and (ii) ascosporic discharge in response to duration of leaf wetness and prevailing temperatures. P. macularis ascospores were confirmed to be infectious at temperatures ranging from 5 to 20°C. The organism's chasmothecia were also found to adhere tightly to the host tissue on which they formed, suggesting that these structures likely overwinter wherever hop tissue senesces within a hop yard. These observations suggest that existing early season disease management practices are especially crucial to controlling hop powdery mildew in the presence of P. macularis chasmothecia. Furthermore, these insights provide a baseline for the validation of weather-driven models describing maturation and release of P. macularis ascospores, models that can eventually be incorporated into hop disease management programs.

The Effects of Exercise on ß-Hydroxybutyrate Concentrations over a 36-h Fast: A Randomized Crossover Study.

PURPOSE: This study assessed ß-hydroxybutyrate (BHB) concentration during a short-term fast and the degree to which an initial bout of exercise influences the rate of ketogenesis. METHODS: Twenty subjects (11 male, 9 female) completed two 36-h fasts, with one protocol requiring the subject to complete a treadmill exercise session at the beginning of the fast. BHB levels were assessed via portable meter every 2 h, along with mood and hunger ratings. Venipuncture was performed every 12 h. RESULTS: The mean (SD) areas under the curve for BHB concentration were 19.19 (2.59) mmol·L-1 (nonexercised) and 27.49 (2.59) mmol·L-1 (exercised), yielding a difference of 8.30 mmol·L-1 between conditions (95% posterior probability interval (PPI), 1.94 to 14.82 mmol·L-1; posterior probability (PP) = 0.99). The mean (SD) times to BHB concentration of 0.5 mmol·L-1 were 21.07 (2.95) h (nonexercised) and 17.5 (1.69) h (exercised), a 3.57-h difference (95% PPI, -2.11 to 10.87 h; PP = 0.89). The differences in area under the curve between conditions were 5.07 µU·mL-1 (95% PPI, -21.64 to 36.18 µU·mL-1; PP = 0.67) for insulin, 97.13 pg·mL-1 (95% PPI, 34.08 to 354.21 pg·mL-1; PP = 0.98) for glucagon, and 20.83 (95% PPI, 4.70 to 24.22; PP = 0.99) for the insulin/glucagon ratio. CONCLUSIONS: Completing aerobic exercise at the beginning of a fast accelerates the production of BHB throughout the fast without altering subjective feelings of hunger, thirst, stomach discomfort, or mood. Insulin and the insulin/glucagon ratio experience a marked reduction within the first 12 h of fasting and was not altered with exercise. Thus, exercising at the beginning of a fast may improve the metabolic outcomes of fasting.

Mediators of suicidality 12 years after bariatric surgery relative to a nonsurgery comparison group.

BACKGROUND: Individuals undergoing bariatric surgery report higher levels of suicidality than the general population, but it is unknown what mediates this phenomenon or how this compares with individuals with severe obesity not receiving surgery. OBJECTIVES: We evaluated suicidality in 131 individuals 12 years post surgery compared with 205 individuals with severe obesity who did not undergo surgery. Changes in health-related quality of life (HRQOL) and metabolic health were assessed as mediators of suicidality. SETTING: University. METHODS: Suicidality was assessed with the Suicide Behaviors Questionnaire-Revised at 12 years. Metabolic health and HRQOL (Short Form-36 [SF-36] Mental Component Summary score, Physical Component Summary score, and Impact of Weight on Quality of Life-Lite) were assessed at baseline and 2 and 6 years. The effects of bariatric surgery on suicidality at 12 years were assessed through univariate and multivariate sequential moderated mediation models, with changes in metabolic health and HRQOL from 0-2 years and 2-6 years as mediators. RESULTS: Suicidality was higher in the surgery group versus the nonsurgery group (estimate [est.] = .708, SE = .292, P < .05). Only the indirect pathways at 2 years after surgery for SF-36 Mental Component Summary in the univariate models (est. = -.172, SE = .080, P < .05) and for SF-36 Physical Component Summary in the multivariate model (est. = .593, SE = .281, P < .05) were significant. CONCLUSION: Individuals undergoing bariatric surgery reported higher levels of suicidality at 12 years, which was mediated by less improvement in the mental and physical components of HRQOL in the first 2 years after surgery, suggesting the need for additional clinical monitoring.

Transcriptome-Derived Amplicon Sequencing Markers Elucidate the U.S. Podosphaera macularis Population Structure Across Feral and Commercial Plantings of Humulus lupulus.

Obligately biotrophic plant pathogens pose challenges in population genetic studies due to their genomic complexities and elaborate culturing requirements with limited biomass. Hop powdery mildew (Podosphaera macularis) is an obligately biotrophic ascomycete that threatens sustainable hop production. P. macularis populations of the Pacific Northwest (PNW) United States differ from those of the Midwest and Northeastern United States, lacking one of two mating types needed for sexual recombination and harboring two strains that are differentially aggressive on the cultivar Cascade and able to overcome the Humulus lupulus R-gene R6 (V6), respectively. To develop a high-throughput marker platform for tracking the flow of genotypes across the United States and internationally, we used an existing transcriptome of diverse P. macularis isolates to design a multiplex of 54 amplicon sequencing markers, validated across a panel of 391 U.S. samples and 123 international samples. The results suggest that P. macularis from U.S. commercial hop yards form one population closely related to P. macularis of the United Kingdom, while P. macularis from U.S. feral hop locations grouped with P. macularis of Eastern Europe. Included in this multiplex was a marker that successfully tracked V6-virulence in 65 of 66 samples with a confirmed V6-phenotype. A new qPCR assay for high-throughput genotyping of P. macularis mating type generated the highest resolution distribution map of P. macularis mating type to date. Together, these genotyping strategies enable the high-throughput and inexpensive tracking of pathogen spread among geographical regions from single-colony samples and provide a roadmap to develop markers for other obligate biotrophs.

Associations of Visceral, Subcutaneous, Epicardial, and Liver Fat with Metabolic Disorders up to 14 Years After Weight Loss Surgery.

Background: Bariatric surgery leads to long-term remission and reduced incidence of diabetes, hypertension, and dyslipidemia. Short-term studies suggest reduction in specific fat depots may be more predictive of health improvement than reduced body mass index (BMI). Visceral, subcutaneous, epicardial, and liver fat, measured 11 years after bariatric surgery, were associated with long-term remission and incidence of diabetes, dyslipidemia, and hypertension. Methods: Fat depots an average of 11 (maximum 14) years after surgery were quantified by noncontrast computed tomography in subjects who did (N = 261; 86% gastric bypass) or did not (N = 243) have bariatric surgery. Multiple regression related fat depots to disease endpoints with and without adjustment for change in BMI and surgical status. Results: Visceral fat was 42% lower, subcutaneous fat 20% lower, epicardial fat 30% lower, and liver-to-spleen density ratio 9% higher at follow-up in the bariatric surgery group compared with the nonsurgery group (all P < 0.01). Higher visceral fat at follow-up exam was significantly associated with reduced remission and increased incidence of diabetes, hypertension, and dyslipidemia. Subcutaneous fat was not associated with disease. The liver-to-spleen ratio was associated with the remission and incidence of hypertriglyceridemia and not with other fat depots. Epicardial fat was related to incidence of elevated low-density lipoprotein cholesterol and low high-density lipoprotein cholesterol. Conclusions: Whether or not a patient shows greater long-term diabetes, dyslipidemia, or hypertension remission or incidence after bariatric surgery appears dependent on the amount of fat within specific fat depots measured at follow-up. Furthermore, associations of the three disease endpoints with different fat depots suggest varied fat depot pathology.

Ketones Elicit Distinct Alterations in Adipose Mitochondrial Bioenergetics.

OBJECTIVE: The rampant growth of obesity worldwide has stimulated explosive research into human metabolism. Energy expenditure has been shown to be altered by diets differing in macronutrient composition, with low-carbohydrate, ketogenic diets eliciting a significant increase over other interventions. The central aim of this study was to explore the effects of the ketone ß-hydroxybutyrate (ßHB) on mitochondrial bioenergetics in adipose tissue. METHODS: We employed three distinct systems-namely, cell, rodent, and human models. Following exposure to elevated ßHB, we obtained adipose tissue to quantify mitochondrial function. RESULTS: In every model, ßHB robustly increased mitochondrial respiration, including an increase of roughly 91% in cultured adipocytes, 113% in rodent subcutaneous adipose tissue (SAT), and 128% in human SAT. However, this occurred without a commensurate increase in adipose ATP production. Furthermore, in cultured adipocytes and rodent adipose, we quantified and observed an increase in the gene expression involved in mitochondrial biogenesis and uncoupling status following ßHB exposure. CONCLUSIONS: In conclusion, ßHB increases mitochondrial respiration, but not ATP production, in mammalian adipocytes, indicating altered mitochondrial coupling. These findings may partly explain the increased metabolic rate evident in states of elevated ketones, and may facilitate the development of novel anti-obesity interventions.

A case study exploring associations between popular media attention of scientific research and scientific citations.

The association between mention of scientific research in popular media (e.g., the mainstream media or social media platforms) and scientific impact (e.g., citations) has yet to be fully explored. The purpose of this study was to clarify this relationship, while accounting for some other factors that likely influence scientific impact (e.g., the reputations of the scientists conducting the research and academic journal in which the research was published). To accomplish this purpose, approximately 800 peer-reviewed articles describing original research were evaluated for scientific impact, popular media attention, and reputations of the scientists/authors and publication venue. A structural equation model was produced describing the relationship between non-scientific impact (popular media) and scientific impact (citations), while accounting for author/scientist and journal reputation. The resulting model revealed a strong association between the amount of popular media attention given to a scientific research project and corresponding publication and the number of times that publication is cited in peer-reviewed scientific literature. These results indicate that (1) peer-reviewed scientific publications receiving more attention in non-scientific media are more likely to be cited than scientific publications receiving less popular media attention, and (2) the non-scientific media is associated with the scientific agenda. These results may inform scientists who increasingly use popular media to inform the general public and scientists concerning their scientific work. These results might also inform administrators of higher education and research funding mechanisms, who base decisions partly on scientific impact.

Longitudinal Changes in Cardiac Structure and Function in Severe Obesity: 11-Year Follow-Up in the Utah Obesity Study.

Background Progressive cardiac remodeling and worsening myocardial function over time have been proposed as potential mediators of heart failure in obesity. Methods and Results We serially assessed cardiac structure and function in 254 subjects participating in a longitudinal study of obesity. Demographic, clinical, laboratory, and echocardiographic features were determined at baseline and 2-, 6-, and 11-year follow-up. We measured body mass index (BMI) exposure as the area under the curve of the BMI at each of the 4 visits. At enrollment, mean age of the subjects was 47 years, 79% were women, mean BMI was 44 kg/m2, 26% had diabetes mellitus, 48% had hypertension, and 53% had hyperlipidemia. Between baseline and 11 years, BMI increased by 1.1 and 0.3 kg/m2 in men and women, respectively. There were modest increases in left ventricular (LV) end-diastolic volume, LV mass, and left atrial volume, and significant decreases in early/late mitral diastolic flow velocity ratio and E wave deceleration time. However, there were no significant changes in LV ejection fraction or ratio of early mitral diastolic flow velocity/early mitral annular velocity, whereas right ventricular fractional area change increased. Significant predictors of the change in LV mass were male sex, baseline BMI, BMI area under the curve, and change in LV stroke volume, but not smoking, hypertension, or diabetes mellitus. Conclusions In long-standing, persistent severe obesity, there was evidence of cardiac remodeling over a period of 11 years, but no clear worsening of systolic or diastolic function. Measures of remodeling were most strongly related to BMI. The observed changes might predispose to heart failure with preserved ejection fraction, but are not classic for an evolving dilated cardiomyopathy.

Strength Training and Insulin Resistance: The Mediating Role of Body Composition.

The main objective of the present study was to assess the association between participation in strength training and insulin resistance. Another goal was to assess the influence of several potential confounding variables on the strength training and insulin resistance relationship. Lastly, the influence of waist circumference, fat-free mass (kg), body fat percentage, and the fat-free mass index on the association between strength training and insulin resistance was assessed. This cross-sectional study included 6,561 randomly selected men and women in the U.S. Data were collected using the precise protocol established by NHANES. HOMA-IR was used as the outcome variable to index insulin resistance. Both time spent strength training and frequency of strength training bouts were used as exposure variables. There was not a statistically significant relationship between strength training and insulin resistance in women. However, before and after controlling for 11 potential confounding variables, men who reported no strength training had significantly higher levels of HOMA-IR compared to men who reported moderate or high levels of strength training (F = 9.87, P < 0.0001). Odds ratios were also assessed. Men reporting no strength training had 2.42 times the odds of having insulin resistance compared to men reporting moderate levels of strength training (95% CI: 1.19-4.93). Similarly, men reporting no strength training had 2.50 times the odds of having insulin resistance compared to men reporting high levels of strength training (95% CI: 1.25-5.00). In conclusion, there was a strong relationship between strength training and insulin resistance in U.S. men, but not in U.S. women. Differences in waist circumference, fat-free mass (kg), body fat percentage, and the fat-free mass index, as well as demographic and lifestyle measures, do not appear to mediate the relationship. The present study was not a clinical trial.