Daily energy expenditure through the human life course

Translational disease modeling of peripheral blood identifies type 2 diabetes biomarkers predictive of Alzheimer's disease

Type 2 diabetes (T2D) is a significant risk factor for Alzheimer's disease (AD). Despite multiple studies reporting this connection, the mechanism by which T2D exacerbates AD is poorly understood. It is challenging to design studies that address co-occurring and comorbid diseases, limiting the number of existing evidence bases. To address this challenge, we expanded the applications of a computational framework called Translatable Components Regression (TransComp-R), initially designed for cross-species translation modeling, to perform cross-disease modeling to identify biological programs of T2D that may exacerbate AD pathology. Using TransComp-R, we combined peripheral blood-derived T2D and AD human transcriptomic data to identify T2D principal components predictive of AD status. Our model revealed genes enriched for biological pathways associated with inflammation, metabolism, and signaling pathways from T2D principal components predictive of AD. The same T2D PC predictive of AD outcomes unveiled sex-based differences across the AD datasets. We performed a gene expression correlational analysis to identify therapeutic hypotheses tailored to the T2D-AD axis. We identified six T2D and two dementia medications that induced gene expression profiles associated with a non-T2D or non-AD state. We next assessed our blood-based T2DxAD biomarker signature in post-mortem human AD and control brain gene expression data from the hippocampus, entorhinal cortex, superior frontal gyrus, and postcentral gyrus. Using partial least squares discriminant analysis, we identified a subset of genes from our cross-disease blood-based biomarker panel that significantly separated AD and control brain samples. Finally, we validated our findings using single cell RNA-sequencing blood data of AD and healthy individuals and found erythroid cells contained the most gene expression signatures to the T2D PC. Our methodological advance in cross-disease modeling identified biological programs in T2D that may predict the future onset of AD in this population. This, paired with our therapeutic gene expression correlational analysis, also revealed alogliptin, a T2D medication that may help prevent the onset of AD in T2D patients.

One Size Does Not Fit All: The Need for Sex-Specific Precision Medicine in Diabetes Technology

Incorporating sex-specific factors in diabetes research and treatment is essential for advancing precision medicine. There are critical gaps in understanding and applying sex-related differences. Female-specific diabetes pathophysiology manifests in three major areas: life cycle phases (including puberty, pregnancy, and menopause), lifestyle factors (such as responses to nutrition and physical activity), and insulin pharmacology. These elements significantly affect insulin sensitivity and glycemic control in women, yet are frequently underrepresented or ignored in both research and clinical practice. Greater research and clinical focus across these domains is needed to better understand and address sex-based differences in diabetes. Identifying and filling evidence gaps will support more systematic and effective care.

Telomere-mitochondrial dynamics differ depending on childhood maltreatment history, catabolic postpartum state, and developmental period

Telomere attrition, a hallmark of aging, is linked to high-energy demand states like early development and biological or psychological stress. Metabolic regulation of telomere length (TL) may occur in these states as part of an energetic trade-off, prioritizing immediate needs over long-term requirements such as telomere maintenance, though this has not been observed in healthy humans. We examined associations between TL and mitochondrial bioenergetics, density, and DNA markers in immune cells of women at 1-week (n = 175) and 1-year postpartum (n = 106), depending on their history of childhood maltreatment (CM), and in their newborns (n = 132). At 1-week postpartum, a catabolic state of high energy demand, women with lower mitochondrial energy production efficiency exhibited shorter TL. One year later, these dynamics appeared only in women with a history of CM. In newborns, TL was shorter when mitochondrial density-normalized routine and ATP production-related respiration was higher. Mitochondrial DNA copy number was associated with TL in both mothers and newborns, regardless of the energetic state. Our findings suggest that telomere-mitochondrial dynamics can adapt to the body's energetic needs.

"Non-Markovian" and "directional" errors inhibit scientific self-correction and can lead fields of study astray: an illustration using gardening and obesity-related outcomes

Herein we coin the terms non-Markovian error and biased Markovian error to describe categories of scientific errors for which general progress within a field of study may be unlikely to result in scientific self-correction. We provide examples of such errors and show their impact on studies about gardening and obesity.

Metabolic profile of healthy, normal-weight adults with low satiety responsiveness

The aim of this study was to characterize the metabolic profile of healthy, normal-weight adults presenting with low satiety responsiveness. Individuals were categorized with low or high satiety responsiveness (LSR and HSR, respectively) based on the satiety quotient (SQ), a marker of satiety responsiveness, which was calculated following two isocaloric breakfast test meals offered while participants were inside the whole-room indirect calorimeter (WRIC): 1) North American: 55 % carbohydrate, 15 % protein, and 30 % fat; 2) High-protein: 31 % carbohydrate, 43 % protein, and 26 % fat. Following the North American breakfast, participants continued receiving a diet resembling the North American dietary pattern while inside the WRIC for 32 consecutive hours where the following outcome measures were assessed: energy metabolism components, metabolic blood markers, and appetite sensations. Forty-three participants were included; 13 were classified as LSR (n = 3 females; n = 10 males), n = 16 as HSR (n = 10 females; n = 6 males), and n = 14 were uncategorized. Compared with HSR, individuals with LSR had higher body weight (5.4 ± 2.5 kg; P = 0.042) and waist circumference (LSR: 77.5 (7.6) cm; HSR: 70.7 (5.2) cm; P = 0.012). Participants with LSR presented with higher total energy expenditure (184 ± 85 kcal/day; P = 0.040) and carbohydrate oxidation rate (34 ± 13 g/day; P = 0.015). Moreover, individuals in the LSR category presented with weakened satiety response to the meals when compared to those with HSR. Our primary findings were that, compared to individuals with HSR, those in the LSR category exhibited differences in their metabolic profile. The long-term impact on body weight and overall health should be assessed in further studies.

Self-rated health habits, mental health, emotional intelligence, and impulsivity across the Baltic States

Introduction

The study aims to compare physical activity, sleep, body mass index (BMI), subjective health, stress, depression, impulsivity, and emotional intelligence across the Baltic countries while identifying key health determinants.

Methods

We interviewed men and women (18-64 years) in Estonia (n = 1,503) Latvia (n = 1,563) and Lithuania (n = 2,358) via an online survey.

Results

Obesity is most common among individuals in EE, both males and females, while the highest rates of overweight are observed in EE females and LT males. Sleep duration is comparable across the different countries, with women generally sleeping longer than men (p < 0.05). Sedentary behavior is shortest among LT females and LV males, although in all countries, females tend to sit more than males (p < 0.05). Moderate physical activity (MPA) levels are similar among males, but they are highest among EE females. In contrast, vigorous physical activity (VPA) is most prevalent in LV males and females. Emotional intelligence (EI) is lowest among LV females and EE males, while females consistently exhibit higher EI than males across all countries. Lithuanians frequently rate their health as "excellent" and show the lowest levels of impulsivity. Additionally, depression and stress are lowest in EE females and LV males. Estonians are more likely to eat breakfast regularly and tend to overeat less than their counterparts in LV and LT.

Conclusion

Our research clearly shows that perceived health among the Baltic countries is significantly inversely related to age, perceived stress, depression, and Body Mass Index (BMI). In contrast, we found positive associations between vigorous physical activity (VPA) and emotional intelligence (EI).

The causal relationships between body composition and heart failure: A two-sample mendelian randomization study

The objective of this study was to assess the causal relationships between various body composition indicators, including body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), and specific measures of fat mass (right arm, right leg, trunk, and whole-body fat mass) and fat-free mass, and the risk of heart failure (HF) using a two-sample Mendelian randomization (MR) approach. We used genome-wide significant single nucleotide polymorphisms (SNPs) related to body composition from the UK Biobank, GIANT, and FinnGen as instrumental variables. To estimate causal associations, we applied multiple methods, including inverse variance weighted (IVW), IVW with multiplicative random effects (IVW_mre), MR-PRESSO, and maximum likelihood. The results demonstrated that each standard deviation (SD) increase in BMI (OR = 1.48; 95% CI: 1.37-1.60; P = 1.24E-23), WC (OR = 1.60; 95% CI: 1.45-1.77; P = 1.72E-20), and WHR (OR = 1.25; 95% CI: 1.01-1.54; P = 3.70E-02) was significantly associated with increased HF risk. Comparable associations were observed for fat mass in the right arm (OR = 1.42; P = 6.60E-17), right leg (OR = 1.57; P = 5.80E-18), trunk (OR = 1.31; P = 3.02E-11), and the whole body (OR = 1.34; P = 2.24E-12). Fat-free mass-both whole-body (OR = 1.34; P = 4.77E-10) and regional measurements (right arm, right leg, trunk)-also exhibited positive associations with HF risk. Leave-one-out analyses confirmed the stability of these findings and underscored the significance of multiple body composition indicators in HF risk assessment and prevention.

Body weight reduction in women treated with tirzepatide by reproductive stage: a post hoc analysis from the SURMOUNT program

OBJECTIVE

Increases in adiposity and adverse changes in adipose distribution commonly occur in women during midlife and with the onset of menopause. This post hoc analysis assessed body weight changes with tirzepatide by reproductive stage.

METHODS

Women participants from SURMOUNT-1, -3, and -4 randomized to tirzepatide (15 mg or maximum tolerated dose) or placebo were retrospectively categorized as being in the pre-, peri-, or post-menopause stages. Body weight and waist circumference changes, the proportion of participants achieving body weight-reduction thresholds, and waist to height ratio (WHtR) category shift among those with baseline BMI < 35 kg/m2 were assessed at end of study treatment.

RESULTS

In SURMOUNT-1, significantly greater body weight reductions from baseline were observed with tirzepatide versus placebo in women in the premenopause (26% vs. 2%), perimenopause (23% vs. 3%), and postmenopause stages (23% vs. 3%; p < 0.001). Greater waist circumference reductions were also observed with tirzepatide across the subgroups (22 vs. 4 cm, 20 vs. 5 cm, and 20 vs. 4 cm, respectively; p < 0.001). Across the reproductive stage subgroups, 97% to 98% of participants achieved body weight reductions that were ≥5% with tirzepatide versus 29% to 33% with placebo. Furthermore, 30% to 52% of women among the reproductive stage subgroups who had baseline BMI < 35 kg/m2 reached WHtR ≤ 0.49 (low central adiposity) with tirzepatide. Similar results were observed in SURMOUNT-3 and -4.

CONCLUSIONS

In this post hoc analysis, tirzepatide treatment was associated with significant body weight, waist circumference, and WHtR reductions versus placebo in women living with obesity or overweight and without type 2 diabetes, irrespective of reproductive stage.

Improving HbA1c Levels by Methylcobalamin Vitamin in Diabetic Volunteers, Combined with Dapagliflozin as Type 2 Diabetes Mellitus Routine Treatment: A Controlled Randomized, Double-blind Trial

Background

Diabetes mellitus is predominantly a growing global problem interconnected proportionally with obesity escalation. The current study evaluated the prognostic implications of vitamin B12 administration on Body Mass Index (BMI) and glycosylated hemoglobin (HbA1c) levels in type 2 diabetic patients treated with dapagliflozin.

Methods

In this controlled randomized, double-blind trial, 160 patients for each arm were enrolled from July 2022 to June 2023 in Amman, Jordan.; 76 females and 84 males with inclusion criteria of vitamin B12 less than 233 ng/ml, age between 19-76 years, HbA1c range between 6.8-9.1%, and BMI less than 35. Group I received only dapagliflozin 10 mg/daily for a period of 12 months, whereas, group II received vitamin B12 supplements, methylcobalamin 500 µg, once daily with dapagliflozin 10 mg/day. HbA1c, Vitamin B12, and BMI were measured at time intervals of 0, 6, and 12 months. Using SPSS version 23, P values<0.05 were considered statistically significant. The continuous variables were reported as median and IQR. Mann-Whitney-u test and Correlations Spearman's rho were used for continuous variables.

Results

The co-administration of vitamin B12 significantly decreased the levels of HbA1c in group II (54 participants) to 6.66±0.643 by 0.6 %, F(2,78)=172, P<0.001, compared to the subjects in group I (6.92±0.434). A significant impact of vitamin B12 administration on BMI lowering was observed at different time intervals during the study (P=0.002).

Conclusion

The co-administration of vitamin B12 as a supplement for diabetic patients improved BMI and HbA1c levels.Trial Registration Number: NCT06241638.

Haem biosynthesis regulates BCAA catabolism and thermogenesis in brown adipose tissue

The distinctive colour of brown adipose tissue (BAT) is attributed to its high content of haem-rich mitochondria. However, the mechanisms by which BAT regulates intracellular haem levels remain largely unexplored. Here we demonstrate that haem biosynthesis is the primary source of haem in brown adipocytes. Inhibiting haem biosynthesis results in an accumulation of the branched-chain amino acids (BCAAs) valine and isoleucine, owing to a haem-associated metabolon that channels BCAA-derived carbons into haem biosynthesis. Haem synthesis-deficient brown adipocytes display reduced mitochondrial respiration and lower UCP1 levels than wild-type cells. Although exogenous haem supplementation can restore intracellular haem levels and mitochondrial function, UCP1 downregulation persists. This sustained UCP1 suppression is linked to epigenetic regulation induced by the accumulation of propionyl-CoA, a byproduct of disrupted haem synthesis. Finally, disruption of haem biosynthesis in BAT impairs thermogenic response and, in female but not male mice, hinders the cold-induced clearance of circulating BCAAs in a sex-hormone-dependent manner. These findings establish adipose haem biosynthesis as a key regulator of thermogenesis and sex-dependent BCAA homeostasis.

Sex-specific energy expenditure during the Alaska mountain wilderness ski classic; insights from an Arctic winter expedition

Purpose

The Alaska Mountain Wilderness Ski Classic (AMWSC) is a self-supported and self-oriented winter expedition that occurs in the remote North American Brooks Range, ∼200 km north of the Arctic Circle. Few investigations have evaluated sex-specific physiological responses under extreme cold and isolated circumstances. Our study examined sex-specific differences in total energy expenditure (TEE), water turnover (WT), and changes in body composition during the expedition.

Methods

Twenty adult participants (8 females, age: 41 ± 6 years, body mass index: 22.8 ± 1.9 kg/m2 and 12 males, age: 38 ± 4 years, body mass index: 22.7 ± 1.6 kg/m2) enrolled in and completed the study. TEE and WT were examined during the expedition using the doubly labeled water (DLW) method. Body composition was measured using multi-frequency bioelectrical impedance.

Results

The duration of the expedition was similar in females (8.1 ± 1.6 days) and males (7.5 ± 0.9 days). Absolute rates of TEE were lower in females (20.8 ± 4.7 MJ/day) compared to males (31.1 ± 7.5 MJ/day). However, when expressed relative to fat free mass (FFM), rates of TEE were similar in females (0.42 ± 0.07 MJ/FFM/day) and males (0.45 ± 0.10 MJ/FFM/day). TEE/body mass plus pack weight (i.e., total load carriage) was lower in females compared to males. WT was reduced compared to previous reports of athletes exercising in thermoneutral and hot environments.

Conclusion

Absolute rates of TEE were lower in females compared to males, but there was no difference when TEE was expressed relative to fat free mass. Estimates of TEE/total load carriage were lower in females than males, modestly suggesting greater functional efficiency in females during this expedition. Compared to other ultra-endurance events in warm environments, WT may have been reduced by lack of water availability, self-selected reductions in exercise intensity, and limited sweat loss.

Dietary misreporting: a comparative study of recalls vs energy expenditure and energy intake by doubly-labeled water in older adults with overweight or obesity

BACKGROUND

Self-report methods are widely used to assess energy intake but are prone to measurement errors. We aimed to identify under-reported, over-reported, and plausible self-reported energy intake by dietary recalls (rEI) using a standard method (Method 1) that calculates the rEI ratio against measured energy expenditure (mEE) by doubly-labeled water (DLW), and compare it to a novel method (Method 2), which calculates the rEI ratio against measured energy intake (mEI) by the principle of energy balance (EB = mEE + changes in energy stores).

METHODS

The rEI:mEE and rEI:mEI ratios were assessed for each subject. Group cut-offs were calculated for both methods, using the coefficient of variations of rEI, mEE, and mEI. Entries within ± 1SD of the cutoffs were categorized as plausible, < 1SD as under-reported, and > 1SD as over-reported. Kappa statistics was calculated to assess the agreement between both methods. Percentage bias (bβ) was estimated by linear regression. Remaining bias (dβ) was calculated after applying each method cutoffs.

RESULTS

The percentage of under-reporting was 50% using both methods. Using Method 1, 40.3% of recalls were categorized as plausible, and 10.2% as over-reported. With Method 2, 26.3% and 23.7% recalls were plausible and over-reported, respectively. There was a significant positive relationship between mEI with weight (ß = 21.7, p < 0.01) and BMI (ß = 48.8, p = 0.04), but not between rEI with weight (ß = 13.1, p = 0.06) and BMI (ß = 41.8, p = 0.11). The rEI relationships were significant when only plausible entries were included using Method 1 (weight: ß = 17.4, p < 0.01, remaining bias = 49.5%; BMI: ß = 44.6, p = 0.01, remaining bias = 60.2%) and Method 2 (weight: ß = 19.5, p < 0.01, remaining bias = 24.9%; BMI: ß = 44.8, p = 0.03, remaining bias = 56.9%).

CONCLUSIONS

The choice of method significantly impacts plausible and over-reported classification, with the novel method identifying more over-reported entries. While rEI showed no relationships with anthropometric measurements, applying both methods reduced bias. The novel method showed greater bias reduction, suggesting that it may have superior performance when identifying plausible rEI.

CLINICAL TRIALS REGISTRATION

NCT04465721.

The cellular basis for middle-age spread

Age-specific adipocyte progenitors drive visceral adipose tissue expansion in middle age.

Distinct adipose progenitor cells emerging with age drive active adipogenesis

Starting at middle age, adults often suffer from visceral adiposity and associated adverse metabolic disorders. Lineage tracing in mice revealed that adipose progenitor cells (APCs) in visceral fat undergo extensive adipogenesis during middle age. Thus, despite the low turnover rate of adipocytes in young adults, adipogenesis is unlocked during middle age. Transplantations quantitatively showed that APCs in middle-aged mice exhibited high adipogenic capacity cell-autonomously. Single-cell RNA sequencing identified a distinct APC population, the committed preadipocyte, age-enriched (CP-A), emerging at this age. CP-As demonstrated elevated proliferation and adipogenesis activity. Pharmacological and genetic manipulations indicated that leukemia inhibitory factor receptor signaling was indispensable for CP-A adipogenesis and visceral fat expansion. These findings uncover a fundamental mechanism of age-dependent adipose remodeling, offering critical insights into age-related metabolic diseases.

Resting metabolic rate and energy efficiency in response to an intensive 84-day combat-swimmer training in the German Armed Forces

PURPOSE

According to the 'constrained model', there are compensations in resting metabolic rate (RMR) at high levels of physical activity (PA). Here, we have used a standardized combat-swimmer training protocol (CST) to investigate whether changes in RMR (i) confirm the 'constraint model', and (ii) differ between successful participants and dropouts.

METHODS

Controlled 84d CST in 44 male soldiers with 13 finally successful. Fat mass (FM) and fat-free mass (FFM) were measured using Quantitative Magnetic Resonance. RMR was assessed by indirect calorimetry, VO2max, and work efficiency by treadmill spiroergometry. Plasma levels of thyroid hormones, testosterone, and cortisol were analysed by standard laboratory methods.

RESULTS

CST increased VO2max (+ 6.9%) and exercise efficiency at low workloads of 10 and 12 km/h (+ 8.7 and + 6.5%; both p < 0.05). As energy balance was moderately negative (-356 ± 383 kcal/d), FFM and FM decreased (-2 and -16%; both p < 0.05). There was a considerable inter-individual variance but no change in in the mean values of RMR and RMRadjFFM. RMRadjFFM before CST had a negative association with its decrease with CST (p < 0.005). Concomitantly, plasma hormone levels were unchanged. When compared with dropouts, successful participants had a higher VO2max at baseline (5.2 ± 0.6 vs. 4.9 ± 04 l/min; p < 0.05) that increased with CST (+ 4.4 vs. -0.4%; p < 0.05) at similar changes in body composition and energy balance.

CONCLUSION

While CST increased VO2max and exercise efficiency as a compensation, there was an inter-individual variance in exercise-related compensation of RMR with no differences between 'completers' and 'non-completers'. Trial registration DRKS00018850, November 27, 2019.

Impact of Individuals' Biological and Meals' Nutritional Characteristics on the Thermic Effect of Food in Humans: Meta-Regression of Clinical Trials

CONTEXT

The thermic effect of food (TEF) may be a therapeutic target for the prevention and treatment of obesity.

OBJECTIVE

The impact of different biological and nutritional characteristics on TEF in humans was analyzed.

DATA SOURCES

The MEDLINE/PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Latin American and Caribbean Health Sciences Literature databases were searched until November 2023 without language restrictions.

DATA EXTRACTION

Clinical trials were included that offered an oral test meal to adult and elderly individuals in a fasting state and measured TEF using calorimetry. The average TEF of each group was the outcome, and the impact of the individuals' and meal characteristics on the TEF was assessed using subgroups, meta-regression, and compositional analysis.

DATA ANALYSIS

The review included 133 studies, with 321 different groups. The mean TEF at 60 minutes after the test meal was 262 (95% CI, 236-288) kcal/d and decreased over time until 240 minutes after the test meal (P < .01). Male participants, individuals with normal body mass index, meals with energy content offered according to individual requirements, and meals with a mixed degree of food processing yielded a higher TEF. The total energy content of meals was the variable most strongly associated with TEF. Compositional analysis showed that the amount of lipids in meals was the only macronutrient consistently and negatively associated with TEF.

CONCLUSIONS

The TEF is influenced by specific individuals' and meal characteristics. Total energy content and the amount of lipids were the characteristics of the meals most consistently associated with TEF. However, due to important methodological differences between studies, it is difficult to determine how to use TEF as a potential therapeutic target against obesity.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023432504.

The neurobiology of overeating

Food intake serves to maintain energy homeostasis; however, overeating can result in obesity, which is associated with serious health complications. In this review, we explore the intricate relationship between overeating, obesity, and the underlying neurobiological mechanisms. We review the homeostatic and hedonic feeding systems, highlighting the role of the hypothalamus and reward systems in controlling food intake and energy balance. Dysregulation in both these systems leads to overeating, as seen in genetic syndromes and environmental models affecting appetite regulation when consuming highly palatable food. The concept of "food addiction" is examined, drawing parallels to drug addiction. We discuss the cellular substrate for addiction-related behavior and current pharmacological obesity treatments-in particular, GLP-1 receptor agonists-showcasing synaptic plasticity in the context of overeating and palatable food exposure. A comprehensive model integrating insights from addiction research is proposed to guide effective interventions for maladaptive feeding behaviors. Ultimately, unraveling the neurobiological basis of overeating holds promise for addressing the pressing public health issue of obesity.

Investigating the impact of body composition on the estimation of resting metabolic rate: new equations for adults aged ≥65 years developed using cross-sectional data

BACKGROUND

Due to changes in body composition during aging, the inclusion of body composition measures as a variable within equations to predict resting metabolic rate (RMR) may improve their predictive accuracy.

OBJECTIVES

This analysis of cross-sectional data aimed to develop and validate new RMR equations for older adults (≥65 y) incorporating variables for body composition, to predict performance and accuracy, and to explore the relative contribution of body composition variables acting directly or potentially via fat-free mass (FFM) to RMR.

METHODS

Analyses were conducted utilizing a unique international dataset of gold standard measures developed for this purpose. RMR was predicted from potential predictive variables using stepwise multiple regression. Predictive performance of the final model was assessed using double cross-validation. The new prediction equation was compared with published prediction equations for similar populations and with previously published RMR prediction equations that did not include FFM. Direct associations between the determined predictor variables and RMR with indirect effects mediated via FFM were examined using mediation final (or pathway) analysis.

RESULTS

The dataset contained 1238 participants. The predictive equations {utilizing either FFM (Equation 1) or lean body weight [LBW](Equation 2)} follow. Equation 1: RMR = 8.645 × height + 23.684 × weight - 29.717 × age + 38.213 × FFM + 209.637 × sex + 2693.223; Equation 2: RMR = -30.570 × age + 80.736 × LBW - 186.825 × sex + 3956.822 where RMR (kJ/d); height (cm); weight (kg); age (y); FFM (kg); LBW (kg); sex (M = 1, F = 0). The equation performed similarly to some anthropometric-based prediction equations. Predictors using FFM performed marginally better than those using LBW. All variables had significant (P < 0.001) direct effects upon RMR and significant (P < 0.001) indirect effects for sex, weight, and height.

CONCLUSIONS

New prediction equations predict RMR at the population level with minimal bias; however, the difference in performance with anthropometry-based equations is minimal. This may be explained by the contribution of FFM to weight, whereby equations that include weight are already accounting for FFM.

Association between objective physical activity and frailty transition in community-dwelling prefrail Japanese older adults

BACKGROUND

Frailty transition is common, and increased physical activity can prevent it. An objective assessment of physical activity could eliminate bias and provide more precise information on the association between frailty transitions and physical activity.

OBJECTIVES

This study aimed to examine the association between objective physical activity and frailty transition in community-dwelling prefrail Japanese older adults.

DESIGN

This is a retrospective cohort study based on the National Institute for Longevity Science-Longitudinal Study of Aging data.

PARTICIPANTS

A total of 387 community-dwelling older adults with prefrailty were enrolled (mean age 72.0 years).

MEASUREMENTS

Frailty was assessed using modified components of the Cardiovascular Health Study criteria, and frailty statuses were reassessed two years later. The frailty transitions were categorized into three groups: deterioration, persistence, and reversal. Participants wore a uniaxial accelerometer to assess the physical activities. Differences in baseline characteristics according to frailty transitions were assessed. To compare the baseline objective physical activities based on frailty transition, a general linear model and a logistic regression model were used.

RESULTS

Among the 387 participants, 40 (10.3%) deteriorated to frailty, 97 (25.0%) reversed to robust, and the majority (n = 250, 64.6%) remained prefrail after a 2-year follow-up. Using the general linear model, after adjusting for other factors, total energy expenditure (TEE) in the reversal group was significantly higher than that in the deterioration and persistence groups. No differences in TEE were observed between the persistence and deterioration groups. No significant differences existed in the numbers of daily steps, exercise energy expenditure (EEE) and physical activity with different intensity among these three groups. The logistic model also showed a significant association between TEE and the reversal of frailty.

CONCLUSION

Frailty transitions were common in the Japanese prefrail population. This study showed that a higher TEE was positively associated with frailty reversal in prefrail older adults. Promoting proactive programs for older adults to increase physical activity could help them stay healthy and prevent frailty deterioration.

Heat treatment activates futile calcium cycling in brown adipose tissue to modulate energy metabolism and alters gut microbiota in C57BL/6 mice

AIM

Aging decreases the metabolic rate and increases the risk of metabolic diseases, highlighting the need for alternative strategies to improve metabolic health. Heat treatment (HT) has shown various metabolic benefits, but its ability to counteract aging-associated metabolic slowdown remains unclear. This study aimed to investigate the impact of whole-body HT on energy metabolism, explore the potential mechanism involving the heat sensor TRPV1, and examine the modulation of gut microbiota.

METHODS

Ten-month-old female C57BL/6 mice on a high-fat (HF) diet (45% calories from fat) were exposed to daily HT in a 40-41°C heat chamber for 30 min, 5 days a week for 6 weeks. Metabolic changes, including core body temperature and lipid metabolism transcription in adipose tissue and liver, were assessed. Human brown adipocytes were used to confirm metabolic effects in vitro.

RESULTS

HT significantly reduced serum lactate dehydrogenase levels, indicating mitigation of tissue damage. HT attenuated weight gain, improved insulin sensitivity, and increased beta-oxidation in the liver and brown fat. In thermogenic adipose tissue, HT enhanced TRPV1 and Ca2+/ATPase pump expression, suggesting ATP-dependent calcium cycling, which was confirmed in human brown adipocytes. Interestingly, HT also reduced the firmicutes/bacteroides ratio and altered gut microbiota, suppressing HF diet-enriched microbial genera such as Tuzzerella, Defluviitaleaceae_UCG-011, Alistipes, and Enterorhabdus.

CONCLUSION

HT attenuates aging- and diet-associated metabolic slowdown by increasing futile calcium cycling, enhancing energy expenditure, and altering gut microbiota in middle-aged female C57BL/6 mice. HT may offer a promising strategy to improve metabolic health, especially in aging populations.

Impact of Different Greenspace Metrics on Cardiovascular Disease Incidence in Urban Settings: A Comparative Analysis

Cardiovascular diseases (CVDs) are the leading cause of global mortality, and urban greenspace can reduce CVDs risk. However, the evidence relating various greenspace metrics to CVDs risk is inconclusive. To enhance the understanding of the correlation between greenspace and CVDs, we compared three greenspace indicators-street view-based greenspace (SVG), normalized difference vegetation index (NDVI), and green cover rate (GCR). We used a large sample of 36,504 CVDs hospitalization records with precise residential addresses from 2017 to 2022 in Jingzhou, China. Employing the geographically weighted regression (GWR) model, we investigated the association between greenspace and CVDs incidence at the population level. We found significant negative associations between NDVI/SVG and CVDs incidence (SVG: β = - 1.64; 95% CI, [- 2.12, - 1.15]; NDVI: β = - 8.57; 95% CI, [- 9.81, - 7.33]), with NDVI exhibiting a more substantial protective effect. However, no significant relationship was found in GCR (p = 0.161). The impacts varied by age, but not by gender, with younger individuals benefiting more than the elderly, and SVG showed no significant relationship with CVDs incidence in individuals over 65 years. Our findings suggested the importance of the presence of greenspace in CVDs prevention. Consequently, in urban greenspace planning, priority should be given to the vegetation quantity in residential areas over the size of greenspace facilities located distant from residences.

Testosterone, 8-Oxo-2'-Deoxyguanosine (8-OHdG) and Cu/Zn Superoxide Dismutase (SOD) in Adult Shuar Males of Amazonian Ecuador: A Test for Evidence of Trade-Offs Between Reproductive Effort and Oxidative Stress

OBJECTIVES

Reproductive effort incurs the cost of biological aging and morbidity by compromising somatic maintenance when key resources are limited. Oxidative stress is positively correlated with reproductive effort in adult human females and non-human male animal models, but human males are understudied. We hypothesized that due to its anabolic and metabolic promotion of reproductive effort in human males, testosterone would be positively associated with biomarkers of oxidative stress.

METHODS

Urinary testosterone in adult Shuar males of Amazonia Ecuador, a foraging/horticultural population, was measured with urinary 8-hydroxy-2' -deoxyguanosine (8-OHdG), a biomarker of oxidative stress, and Cu/Zn superoxide dismutase (Cu/Zn SOD), a protective antioxidant against oxidative stress. Age and anthropometric measures were included in multivariate models.

RESULTS

No significant correlation was observed between testosterone and 8-OHdG, r2 = 0.01, p = 0.61, n = 29, or Cu/Zn SOD, r2 = 0.0005, p = 0.93, n = 17. Multiple linear regression models including testosterone, Cu/Zn SOD, anthropometrics, and age, with 8-OHdG as the dependent variable, were modestly supportive of an association. The most parsimonious 8-OHdG model included age, Cu/Zn SOD, and testosterone (R2 adjusted = 0.38, p = 0.04, AICc = 141.95). All multivariate models for Cu/Zn SOD were not significant (p > 0.05).

CONCLUSIONS

Oxidative stress may not be a cost of reproductive effort in this population of adult males; perhaps due to consistently low testosterone levels in non-industrialized populations, differences in the metabolic cost of reproductive effort between males and females (i.e., aerobic metabolism), and/or study limitations based on cross-sectional measures of oxidative stress and testosterone.

Consumption of lettuce with seaweed extract biostimulant application improved iron homeostasis in a randomized interventional trial of healthy individuals

Minerals have key roles in the body's metabolism and homeostasis. Biostimulants application to vegetables, such as seaweed extracts derived from Ecklonia maxima (SwE), is a useful agronomic approach to improve crop yield and quality by a naturally functionalizing process. We hypothesized that SwE biostimulants would impact the minerals profile of the lettuce and the consumption of lettuce with SwE application would affect blood minerals concentration in the health population. This in turn would impact metabolic pathways essential for human homeostasis. A group 48 healthy adults, of both sexes, was allocated in a double-blinded manner into groups that consumed 100 g a day of control lettuce, lettuce with SwE application or an iron tablet (30 mg) for four weeks. Blood samples were collected at baseline (T0) and at the end of the trial (T2) and compared for differences in serum mineral concentrations, iron, lipid and glucose homeostasis. In lettuce, SwE biostimulant enhanced iron concentration by about 63%. The consumption of lettuce with SwE application increased serum iron by about 38%, transferrin saturation by about 47%, and reduced total cholesterol by about 19% and Low-density lipoprotein by about 22%. Supplementation of iron in tablets has similar effects to lettuce with SwE application but with side effects (diarrhea or constipation). The study offers an innovative perspective by assessing lettuce with SwE application as a natural alternative to iron supplements that are commonly associated with gastrointestinal side effects. The results are of interest in the context of dietary iron deficiency especially among populations that avoid meat-based diets. This research could have broad implications for enhancing the nutritional value of plant-based foods to support dietary health by promoting intersection of sustainable agriculture and human nutrition.Clinical trial registration number: NCT06656871.

Testing the carbohydrate-insulin model: Short-term metabolic responses to consumption of meals with varying glycemic index in healthy adults

The carbohydrate-insulin model predicts that meals with varying glycemic indices will elicit distinct metabolic and hunger responses, including greater intake at subsequent meals following high-glycemic-index meals. To test this, a randomized trial (NCT05804942) was conducted in healthy adults using intervention meals with low, medium, and high glycemic indices and a constant macronutrient composition. After intake of the intervention meals, glucose and insulin followed the predicted pattern, but subjective hunger did not. At the group level, low glycemic index meals led to lower energy intake changes. At the individual level, energy intake changes were unrelated to body fatness or levels of glucose, β-hydroxybutyrate, free fatty acids, L-lactate, leptin, adrenaline, glucagon-like peptide-1, glucagon, and insulin-glucagon ratio. A weak negative association was observed between energy intake changes and insulin or insulin-glucagon ratio at 300 min, opposite to the model's prediction. These data provide little support for the carbohydrate-insulin model.

The effect of carbohydrates with different levels of digestibility on energy metabolism in vivo under hypobaric hypoxic conditions

Current strategies for improving energy supply in hypobaric hypoxic environments are limited. Therefore, this study investigates the effects of four carbohydrates with different levels of digestibility on energy metabolism in vivo in hypobaric hypoxic environments. First, we characterized the four types of carbohydrates. Subsequently, reverse transcription quantitative polymerase chain reaction (RT-qPCR) was used to characterize the expression of GLUT1, GLUT2, and SGLT1 in the glucose transport pathway in vivo. In addition, the effects of different levels of carbohydrate digestibility on energy expenditure were evaluated in vivo. The results showed that pre-gelatinized corn starch significantly increased GLUT1 gene expression in the hypobaric hypoxic conditions (1.58 times, compared to normobaric normoxic). In addition, pre-gelatinized corn starch increased energy expenditure in the hypobaric hypoxic conditions and performed better in terms of glycogen accumulation and glucose transport. Therefore, pre-gelatinized corn starch administration may be a promising strategy for long-term energy supplementation in hypobaric hypoxic.

Association of dietary water intake with body composition and the potential mechanism based on urinary metabolic signatures in Chinese elderly individuals aged 75 years and above

With the rising global aging rate, elderly nutrition and health issues are major concerns. Current research focuses on nutrients such as protein and vitamins, while there are limited studies on water intake in the elderly. The aim of this study was to assess whether Chinese people aged over 75 years are meeting the recommended adequate intake (AI) for total water intake and its relationship with body composition. This was done by exploring potential mechanisms through the analysis of urinary metabolites. Water intake and dietary status were collected from 456 community seniors aged over 75 years using a 24-hour water intake and dietary record form. Body composition was determined by bioelectrical impedance analysis (BIA). We found that 16.01% of community seniors reached the AI. The protein, fat-free mass (FFM) and skeletal muscle mass (SMM) levels were all increased in the AI group compared to the Collapse

Key Words Collapse

MESH Headings

• Humans
• Aged
• Body Composition
• Male
• Female
• Aged, 80 and over
• China
• Drinking
• Diet
• East Asian People

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Grants Collapse

Affiliation(s)

Sai Yao Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Tianlin Gao Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Yajun Liu Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Ying Zhou Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Zhixuan Zhao Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Yinkun Wang Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Xincen Wang Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Aiguo Ma Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Feng Zhong Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.

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Collaborators Collapse

Isotemporal substitution of sedentary time with different physical activity intensities and sleep in obesity parameters across eight latin American countries

This study aimed to examine the associations between substituting sedentary time (ST) with physical activity and sleep with obesity parameters in adults from eight Latin American countries. The sample consisted of 2173 adults aged 18-65 years. Physical activity, ST and sleep were objectively measured using accelerometers. The parameters of obesity were defined using body mass index (BMI) and waist circumference (WC). Regression analyses were conducted for isotemporal analysis of the association between substituting 30 min/day of ST with light physical activity (LPA), moderate to vigorous physical activity (MVPA) and sleep in relation to BMI and WC. Substituting light physical activity with higher intensity was also analyzed. Substituting 30 min/day of ST with MVPA was significantly associated with lower odds of a higher BMI (OR: 0.993, 95%CI 0.990-0.998) and WC (OR: 0.998, 95%CI 0.998-0.999). Conversely, substituting ST with LPA did not show a significant impact on obesity parameters. However, the substitution of 30 min/day of LPA with MVPA was also associated with lower odds of a higher BMI (OR: 0.993, 95%CI 0.989-0.997). The results highlight the importance of replacing ST and increasing the intensity of physical activity as an effective strategy for preventing and managing obesity in Latin America.

Body composition and aging: cross-sectional results from the INSPIRE study in people 20 to 93 years old

Aging is characterized by several major changes, including altered body composition, which is associated with numerous negative clinical consequences such as sarcopenia, osteoporosis, and frailty. The study is to evaluate body composition parameters depending on age and sex in a population ranging from the young adult to the very old, and to identify break points in the association between body composition and age. In this cross-sectional study, we included the enrolment population of the French INSPIRE-T prospective cohort, accounting for 915 subjects (62% female). Age ranged from 20 to 93 years, median age (years) was 63 (IQR 27). Body composition (lean mass, fat mass, and bone mineral content) was assessed with dual-X-ray absorptiometry (DXA). Different break points in the relationship between age and body composition variables in males and females were identified using a segmented regression analysis adjusted on physical activity, nutritional status, educational level, and comorbidities. Lean mass decreased from the age of 55 years for males (CI 95% 44-66) and 31 years for females (CI 95% 23-39). For fat mass, we observed a trend towards an increase with age for males. For females, we observed an increase with age up to age 75 (CI 95% 62-86), followed by a decreasing trend. In this study, we described the relationship between body composition and age as a function of sex, establishing a foundation for further studies on predictive biomarkers of age-related body composition alteration.

Prediction models of basal energy expenditure in children and adolescents across the BMI spectrum based on room calorimetry: a cross-sectional cohort study

BACKGROUND

Existing equations for prediction of basal energy expenditure (BEE) may not be accurate in children with overweight or obesity (OW/OB).

OBJECTIVES

We aimed to develop BEE prediction equations applicable to children and adolescents across a wide BMI spectrum using gold standard room calorimetry.

METHODS

We measured weight, height, waist and hip circumferences, body composition (DXA), and BEE (whole room calorimetry) in a cross-sectional cohort of 1155 healthy children, 5-19 years of age. 67% of the males and 51% of the females were classified as OW/OB. We applied multiple linear regression analyses to develop BEE prediction models for each sex. Using relevant predictors, we developed models with fat-free mass (FFM); waist and hip circumference; weight and height only; and weight only. A representative sample of participants (83 males, 125 females) served as a validation dataset to test model performance. The models' performance in predicting BEE was compared to existing models in the literature.

RESULTS

Model fits (R2) for the new BEE prediction models were = 0.84 (P < 0.0001). Our BEE prediction models performed equally in children with normal weight and OW/OB, with <1.5% difference between the measured versus predicted BEE in the validation dataset for both sexes. In Bland-Altman analysis, our BEE prediction models were superior to existing prediction models, especially for children with higher BEEs.

CONCLUSIONS

New BEE prediction models developed and tested in cohorts representative of children with normal weight and OW/OB had superior performance compared with existing models. The BEE prediction equations based on simple anthropometrics or body composition provided improved accuracy and precision for children with NW or OW/OB, ages 5 to 19. More accurate estimates of BEE should allow for better estimates of energy requirements of children.

Measured and Predicted Resting Metabolic Rate of Dutch and Norwegian Paralympic Athletes

BACKGROUND

Although resting metabolic rate (RMR) is crucial for understanding athletes' energy requirements, limited information is available on the RMR of Paralympic athletes.

OBJECTIVE

The aim of this study was to determine RMR and its predictors in a diverse cohort of Paralympic athletes and evaluate the agreement between measured and predicted RMR from both newly developed and pre-existing equations.

DESIGN

This cross-sectional study, conducted between September 2020 and September 2022 in the Netherlands and Norway, assessed RMR in Paralympic athletes by means of ventilated hood indirect calorimetry and body composition by means of dual-energy x-ray absorptiometry.

PARTICIPANTS

Sixty-seven Paralympic athletes (male: n = 37; female: n = 30) competing in various sports, with a spinal cord disorder (n = 22), neurologic condition (n = 8), limb deficiency (n = 18), visual or hearing impairment (n = 7), or other disability (n = 12) participated.

MAIN OUTCOME MEASURES

RMR, fat-free mass (FFM), body mass, and triiodothyronine (T3) concentrations were assessed.

STATISTICAL ANALYSES

Multiple regression analyses were conducted with height, FFM, body mass, sex, T3 concentration, and disabilities as potential predictors of RMR. Differences between measured and predicted RMRs were analyzed for individual accuracy, root mean square error, and intraclass correlation.

RESULTS

Mean ± SD RMR was 1386 ± 258 kcal/d for females and 1686 ± 302 kcal/d for males. Regression analysis identified FFM, T3 concentrations, and the presence of a spinal cord disorder, as the main predictors of RMR (adjusted R2 = 0.71; F = 50.3; P < .001). The novel prediction equations based on these data, as well as pre-existing equations of Chun and colleagues and Nightingale and Gorgey performed well on accuracy (>60% of participants within 10% of measured RMR), had good reliability (intraclass correlation >0.78), and low root mean square error (≤141 kcal).

CONCLUSIONS

FFM, total T3 concentrations, and presence of spinal cord disorder are the main predictors of RMR in Paralympic athletes. Both the current study's prediction equations and those from Chun and colleagues and Nightingale and Gorgey align well with measured RMR, offering accurate prediction equations for the RMR of Paralympic athletes.

Psychological well-being factors and the likelihood of transitioning from overweight and obesity to normal weight at population level: Evidence from two cohort studies of UK adults

We examined the prospective associations between psychological well-being related factors (depressive symptoms, life satisfaction, self-efficacy) and transitioning from overweight and obesity to normal body weight (vs persistence of overweight and obesity) and change in body mass index (BMI). We used multiple baselines and follow-ups from the National Child and Development Study (NCDS; 8513 observations) and the British Cohort Study (BCS; 11,113 observations). A proportion (8%-9%) of participants with overweight and obesity (BMI ≥25) at baseline transitioned into normal weight (BMI 18.5-<25) by follow-ups. There was no evidence of better psychological well-being related factors (e.g. lower depressive symptoms) being significantly associated with a transition from overweight and obesity to normal weight or reduced BMI in each cohort and pooled cohort analyses. However, age and gender were associated with transition. At population level, better psychological well-being may not be associated with likelihood of weight loss once obesity is developed in adulthood.

Symmetry as a Fundamental Principle in Defining Gene Expression and Phenotypic Traits

Symmetry refers to properties that remain invariant upon mathematical transformations. The principles of symmetry have guided numerous important discoveries in physics and chemistry but not in biology and medicine. Here, we aim to explore the presence of symmetry relationships at the gene expression level as a mean to distinguish between healthy and disease states. We deployed Learning-Based Invariant Feature Engineering - LIFE, a hybrid machine learning approach implemented with two symmetric invariant feature functions (IFFs) to identify Invariant Feature Genes (IFGs), which are gene pairs whose IFF single-value outputs remain invariant across individual samples in a given biological phenotype. Our multiclass classification results across the transcriptomes of 25 normal organs, 25 cancer types, and blood samples obtained from 4 different types of neurodegenerative diseases revealed the presence of unique phenotype-specific IFGs. We constructed networks using these IFGs (IF-Nets) and intriguingly, we demonstrated that the hubs could serve as information encoders, capable of reconstructing sample-wise expression values in relation to their counterpart genes. More importantly, we found that hubs of cancer IF-Nets were enriched with both approved and clinical trial drugs, highlighting "symmetry breaking" as a novel approach for treating diseases.

Effects of Aerobic Exercise on Blood Lipids in People with Overweight or Obesity: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

This study aimed to investigate the effects of aerobic exercise (AE) on triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) levels in people with overweight or obesity. Searches were performed in PubMed, Scopus, Cochrane, and Web of Science, covering data up to 27 October 2023. A meta-analysis was conducted to determine the standardized mean difference (SMD) and 95% confidence interval. Nineteen studies met the inclusion criteria. AE significantly improved blood lipids in people with overweight or obesity (TG: SMD = -0.54; p < 0.00001; TC: SMD = -0.24; p = 0.003; HDL: SMD = 0.33; p = 0.003; LDL: SMD = -0.42; p = 0.0005). Both moderate-intensity and vigorous-intensity AE demonstrated significant impacts in reducing TC, TG, and LDL, whereas only moderate-intensity exercise significantly elevated HDL. Additionally, AE significantly optimized blood lipids in those with overweight, with TG being the only parameter showing improvement in individuals with obesity. Moreover, continuous AE notably improved HDL and TG, while interval AE significantly reduced TG, TC, and LDL. Lastly, a clear positive correlation emerged between the duration of the intervention and the decrease in LDL, and a distinct negative correlation was observed between session duration and the reduction of LDL.

Energy intake insufficiency due to underestimated energy requirement by common predictive formulas can be identified by urinary amino acid levels in advanced heart failure

Background

Elevated resting energy expenditure (REE) promotes cachexia, worsening prognosis in patients with advanced heart failure (HF). However, adequate assessment of energy balance is challenging because of unvalidated common prediction methods and unestablished determinants of REE, resulting in a lack of biomarkers for predicting insufficient energy intake.

Objective

This cross-sectional study aimed to evaluate REE in patients with advanced HF and explore biomarkers for insufficient energy intake.

Methods

We measured REE by indirect calorimetry and calculated the total energy expenditure (TEE) of 72 hospitalized patients with advanced-stage HF. We compared these values with commonly-used formulas and analyzed the associations between REE per body weight (REEBW) and parameters related to hemodynamics and HF severity. In 17 of 72 patients, plasma amino acid (AA) and 24-h urinary AA concentrations were measured to analyze their correlations with energy balance, the ratio of caloric intake to REE.

Results

Resting energy expenditure and TEE values were significantly higher than the predicted values. The mean REEBW was 25 kcal/kg/day, while that for the underweight (<18.5 kg/m2) was 28 kcal/kg/day. We found a significant negative correlation between REEBW and body mass index (BMI), but no significant correlation between REEBW and HF-related parameters. The difference between TEE and predicted TEE using the European Society for Clinical Nutrition and Metabolism formula was most significant in the underweight patients because of underestimation, whereas TEE and pTEE using our modified formula with coefficients by BMI categories did not differ. There was a significant correlation between energy balance and urinary histidine and its metabolite 3-methylhistidine excretion, but no significant correlation with serum albumin and other AA concentrations.

Conclusion

Underweight patients with advanced HF require more energy per weight than the predicted value. Our proposed formula for pTEE in each BMI category may be useful in clinical practice to avoid underestimation of daily energy requirements. Inadequate energy intake, even with such an approach, may be identified by decreased urinary essential AA levels.

Hypoxia as a medicine

Oxygen is essential for human life, yet a growing body of preclinical research is demonstrating that chronic continuous hypoxia can be beneficial in models of mitochondrial disease, autoimmunity, ischemia, and aging. This research is revealing exciting new and unexpected facets of oxygen biology, but translating these findings to patients poses major challenges, because hypoxia can be dangerous. Overcoming these barriers will require integrating insights from basic science, high-altitude physiology, clinical medicine, and sports technology. Here, we explore the foundations of this nascent field and outline a path to determine how chronic continuous hypoxia can be safely, effectively, and practically delivered to patients.

Statistical inference on change points in generalized semiparametric segmented models

The segmented model has significant applications in scientific research when the change-point effect exists. In this article, we propose a comprehensive semiparametric framework in segmented models to test the existence and estimate the location of change points in the generalized outcome setting. The proposed framework is based on a semismooth estimating equation for the change-point estimation and an average score-type test for hypothesis testing. The root-n consistency, asymptotic normality, and asymptotic efficiency of estimators for all parameters in the segmented model are rigorously studied. The distribution of the average score-type test statistics under the null hypothesis is rigorously derived. Extensive simulation studies are conducted to assess the numerical performance of the proposed change-point estimation method and the average score-type test. We investigate change-point effects of baseline glomerular filtration rate and body mass index on bleeding after intervention using data from Blue Cross Blue Shield. This application study successfully identifies statistically significant change-point effects, with the estimated values providing clinically meaningful insights.

Effect of different forms of high-intensity interval training on V̇O2max, strength, flexibility, and body fat percentage among middle-aged males

BACKGROUND

High-intensity interval training (HIIT) has become a popular exercise approach due to its potential to elicit significant physiological adaptations. However, limited research has compared the effects of different HIIT modalities on fitness parameters in middle-aged males. This study aimed to determine the effect of different HIIT on V̇O2max, strength, flexibility, and body fat percentage among middle-aged males.

METHODS

Thirty sedentary males aged 40-50 years were randomly assigned to HIIT-Weight Training Circuit (WTC), HIIT-Shuttle Run (SR), or HIIT-Bodyweight Exercise (BWE) groups. Training consisted of 20 sessions over 5 weeks of 4×4 minutes at 90-95% HRmax with 3 minutes recovery at 70% HRmax between intervals. Outcome measures including V̇O2max, strength, flexibility, and body fat percentage were assessed pre- and postintervention.

RESULTS

The result for the Two-Way Mixed ANOVA indicated there was no significant interaction effect between the three training groups. There was no significant main effect for the three training groups, whereas there was a significant effect for the repeated measure time existed. A significant improvement in V̇O2max, strength, flexibility has been shown between post-test and pre-test for the HIIT-SR, HIIT-WTC, and HIIT-BWE group. Whereas A significant decrease has been shown between post and pretest for all the groups in body fat percentage.

CONCLUSIONS

This research findings suggested that different forms of HIIT can elicit differential adaptation in middle-aged males. Incorporating different form of HIIT as HITT-SR, HITT-WTC, and HITT-BWE into exercise program may be an effective way to systematically improve V̇O2max, strength, flexibility, and body composition in middle-age male population. These findings provide guidance on HIIT prescription according to fitness goals.

Predictive equation derived from 6,497 doubly labelled water measurements enables the detection of erroneous self-reported energy intake

Nutritional epidemiology aims to link dietary exposures to chronic disease, but the instruments for evaluating dietary intake are inaccurate. One way to identify unreliable data and the sources of errors is to compare estimated intakes with the total energy expenditure (TEE). In this study, we used the International Atomic Energy Agency Doubly Labeled Water Database to derive a predictive equation for TEE using 6,497 measures of TEE in individuals aged 4 to 96 years. The resultant regression equation predicts expected TEE from easily acquired variables, such as body weight, age and sex, with 95% predictive limits that can be used to screen for misreporting by participants in dietary studies. We applied the equation to two large datasets (National Diet and Nutrition Survey and National Health and Nutrition Examination Survey) and found that the level of misreporting was >50%. The macronutrient composition from dietary reports in these studies was systematically biased as the level of misreporting increased, leading to potentially spurious associations between diet components and body mass index.

Oxidative Stress in Children and Adolescents: Insights Into Human Biology

Oxidative stress (OS) is a key biological challenge and selective pressure for organisms with aerobic metabolism. The result of the imbalance between reactive oxygen species production and antioxidant defense, OS can damage proteins, lipids, and nucleic acids and plays an important role in driving variation in biological aging and health. Among humans, OS research has focused overwhelmingly on adults, with demonstrated connections between OS, inflammation, and metabolic and neurodegenerative conditions. Relatively little attention has been given to OS during childhood and adolescence. This lack of early life OS research exists despite clear implications for informing human life history evolution, subadult development, and lifelong health. Here, we review current knowledge on OS during human subadulthood. Our objectives are threefold: (1) To highlight common methods for measuring OS among children and adolescents and to establish typical measurement values; (2) To summarize the evidence linking demographic and ecological factors to variation in subadult OS; (3) To identify avenues for future OS research in human biology. Our review underscores an expanding methodological toolkit for assessing OS among children and adolescents. Subadult OS is considerably elevated compared to OS among adults, a pattern eliciting unknown consequences and likely related to increased early life metabolic demands (e.g., unique human brain development). Factors such as diet, physical activity, infectious disease, and structural neglect also appear to drive subadult OS. Current limitations for research on subadult OS are evident. Future work should emphasize evolutionary, biocultural, and energetic life course perspectives to advance this promising area of human biology.

Comparison of diet and exercise on cardiometabolic factors in young adults with overweight/obesity: multiomics analysis and gut microbiota prediction, a randomized controlled trial

The optimal strategy for improving cardiometabolic factors (CMFs) in young obese individuals through diet and exercise remains unclear, as do the potential mechanisms. We conducted an 8-week randomized controlled trial to compare the effects of different interventions in youth with overweight/obesity. Gut microbes and serum metabolites were examined to identify regulating mechanisms. A total of 129 undergraduates were randomly assigned to fiber-rich (FR) diet, rope-skipping (RS), combined FR-RS and control groups. The results showed that single interventions were as effective as combined interventions in improving weight, waist circumference, body fat, and lipid profile compared with control group. Notably, the FR group further reduced low-density lipoprotein (LDL-C) and uric acid (UA) (all p < 0.05). Mediation analysis revealed four gut microbiota-metabolite-host axes in improving CMFs. Additionally, we used machine learning algorithms to further predict individual responses based on baseline gut microbiota composition, with specific microbial genera guiding targeted intervention selection. In conclusion, FR diet and/or RS were effective in improving CMFs, with the FR diet particular effectiveness in reducing LDL-C and UA levels. These benefits may drive by gut microbiome-metabolite-host interactions. Moreover, the predictability of gut microbiota composition supports making targeted decisions in selecting interventions. Trial Registration: NCT04834687.

Cross-disease modeling of peripheral blood identifies biomarkers of type 2 diabetes predictive of Alzheimer's disease

Type 2 diabetes (T2D) is a significant risk factor for Alzheimer's disease (AD). Despite multiple studies reporting this connection, the mechanism by which T2D exacerbates AD is poorly understood. It is challenging to design studies that address co-occurring and comorbid diseases, limiting the number of existing evidence bases. To address this challenge, we expanded the applications of a computational framework called Translatable Components Regression (TransComp-R), initially designed for cross-species translation modeling, to perform cross-disease modeling to identify biological programs of T2D that may exacerbate AD pathology. Using TransComp-R, we combined peripheral blood-derived T2D and AD human transcriptomic data to identify T2D principal components predictive of AD status. Our model revealed genes enriched for biological pathways associated with inflammation, metabolism, and signaling pathways from T2D principal components predictive of AD. The same T2D PC predictive of AD outcomes unveiled sex-based differences across the AD datasets. We performed a gene expression correlational analysis to identify therapeutic hypotheses tailored to the T2D-AD axis. We identified six T2D and two dementia medications that induced gene expression profiles associated with a non-T2D or non-AD state. Finally, we assessed our blood-based T2DxAD biomarker signature in post-mortem human AD and control brain gene expression data from the hippocampus, entorhinal cortex, superior frontal gyrus, and postcentral gyrus. Using partial least squares discriminant analysis, we identified a subset of genes from our cross-disease blood-based biomarker panel that significantly separated AD and control brain samples. Our methodological advance in cross-disease modeling identified biological programs in T2D that may predict the future onset of AD in this population. This, paired with our therapeutic gene expression correlational analysis, also revealed alogliptin, a T2D medication that may help prevent the onset of AD in T2D patients.

Early Life Energy Balance: The Development of Infant Energy Expenditure and Intake in the Context of Obesity

PURPOSE OF REVIEW

This review aims to provide a summary of the current knowledge on measurement tools and most recent evidence for prenatal and postnatal modulators of energy balance in young infants.

RECENT FINDINGS

The prevention of pediatric obesity depends upon curating the perfect imbalance of energy intake to energy expenditure, taking into consideration the energy needs for healthy growth. We summarize the recent evidence for the programming of fetal and infant metabolism influenced by maternal preconception health, prenatal metabolic milieu, and physical activity behaviors. In the early postnatal environment, caregiver feeding behaviors shape the extent of energy imbalance through dictating quantity and modality of infant energy intake. There are biological and behavioral contributors to improper infant energy imbalance. Furthermore, caregiver and clinician education on overfeeding and clinical tools to prescribe and monitor infant overgrowth are absent. Ultimately, the lack of high-quality and modern research of infant energy expenditure underpins the lack of advancement in clinical guidelines and the needed prevention of pediatric obesity.

Reproductive endocrinology and aging in human males: An evolutionary perspective

Due to its important role in fertility, reproductive endocrine function has been subject to natural selection in all organisms including human males. Moreover, reproductive endocrine function is subject to change as males age. Indeed, the biology of aging is also subject to natural selection. As males age, hormone function such as variation in testosterone can change as the result of general somatic degradation. However these changes are not universal and can differ between human male populations depending on lifestyle and ecological context. The degree to which this variation is adaptive remains an open question but recent evolutionary anthropology research has provided some clarity. While knowledge of evolutionary approaches has limitations, the benefits of understanding the origins and comparative context of reproductive endocrine function in older human males are significant. This paper discusses our present comprehension of reproductive endocrinology and aging in human males, with a focus on human diversity across varied lifestyles, ecologies, and environments. In addition, comparative great ape research is examined. Current research challenges and future directions related to the importance of evolutionary biology and human diversity for understanding human male aging are discussed.

The vices and virtues of medical models of obesity

Despite numerous public health organizations supporting the pathologization of obesity and considering recent obesity rates a health crisis, many researchers in the humanities, social sciences, and even in the health sciences remain unconvinced. In this paper, we address a set of arguments coming from these academic fields that criticize medical models of obesity for their supposedly flawed diagnostic categories that shift focus onto individuals and support moralizing judgements. Clarifying some key claims in these models and explicating the view of obesity in terms of energy dysregulation, we aim to tease apart misunderstandings and argue that not only do these models not say what they are often accused of saying, but their apparent vices may actually be virtues in helping to combat stigma. Building on the social psychology of stigma and disease labeling, we then suggest that current medical models are largely supportive of many moral and political aims promoted by critics of these models.

The Effects of Bitter Melon ( Mormordica charantia ) on Lipid Profile: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Research indicates that bitter melon could be useful in the management of dyslipidemia. Still, there is disagreement concerning the findings. This systematic study was undertaken to clarify the impact of consuming bitter melon on lipid profile. The databases Web of Science, Cochrane Library, PubMed, and Scopus were queried from inception until February 9, 2023. The study assessed triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) levels. The effect sizes were calculated using weighted mean differences (WMDs) and 95% confidence intervals (CIs). Eight randomized controlled trials (RCTs) with a total of 423 participants were included. Bitter melon consumption resulted in a significant decrease in plasma concentrations of TC (WMD; -9.71 mg/dL; CI: -17.69 to -1.74, p = 0.01) and TG (WMD; -10.24 mg/dL; CI: -19.92 to -0.56, p = 0.03), while bitter melon did not significantly lower blood LDL-C (WMD; -8.66 mg/dL; CI: -19.83 to 2.50, p = 0.12) and HDL-C concentrations (WMD; 0.54 mg/dL; CI: -2.38 to 3.45, p = 0.71). Subgroup analysis showed a significant decrease in TC and LDL-C and an increase in HDL-C at a dose of ≤ 2000 mg/day and an intervention period of ≤ 8 weeks. Also, the greatest impact of LDL-C and HDL-C was seen in diabetic and prediabetic people. Bitter melon supplementation positively impacts TC and TG levels. The limitations of this study were short-term trials (less than 3 months).

Decline in Isotope Dilution Space Ratio Above Age 60 Could Affect Energy Estimates Using the Doubly Labeled Water Method

BACKGROUND

Doubly labeled water is gold standard for measuring total energy expenditure (TEE). Measurements using the method are sensitive to the isotope dilution space ratio (DSR). Accuracy and precision of the method might be improved if we could identify factors influencing DSR.

OBJECTIVES

We evaluated the potential associations of age, sex, ethnicity, anthropometry, body composition, turnover rates of the isotopes, and geographical elevation with DSR.

METHODS

We used univariate regression analysis to explore the relationships between the continuous variables and analysis of variance to test the relationships between the categorical variables with DSR. Subsequently, we used general linear model (GLM) and 1-way analysis of variance to evaluate the simultaneous associations of age, sex, ethnicity, fat-free mass (FFM) and fat mass (FM) on DSR.

RESULTS

From 5678 measurements complied from studies around the world with diverse ethnicity and living at various elevations, the mean DSR was 1.0364 ± 0.0141. No meaningful physiologic effect of any of the continuous and categorical variable on DSR was detected. General linear model analysis revealed no effect of FFM and FM (P > 0.33) on DSR, but DSR decreased with age (P < 0.001) among those aged 60 y and older regardless of sex. Among the Whites who were younger than 60 y, DSR was not related to FFM and FM (P = 0.73) but was affected by both age and sex (P < 0.001).

CONCLUSIONS

Previous estimates of age-related decline in TEE may have overestimated TEE at age 90 y. Validation studies on older participants are required to confirm this finding.

Water intake in athletes: Agreement between food records and isotope-dilution methods

BACKGROUND

Although water intake (WI) is commonly estimated through self-reporting, its inaccuracy is reported. Water turnover (rH2O)-derived WI is the reference method; however, it is costly. The study aimed to validate alternative methods for determining WI in a group of athletes.

METHODS

Eighty-two athletes (20.4 ± 5.1 years; 28 females) were included in this cross-sectional validation study. Doubly labelled water (DLW) determined rH2O and rH2O-derived WI by subtracting metabolic, transcutaneous, and inspired water from rH2O (reference). The rH2O components were determined by alternative approaches: i) average values of macronutrients instead of individual food records (DLW-derived WI); ii) estimating total energy expenditure (TEE) and rCO2 through a predictive equation instead of DLW (2H-derived WI); iii) estimating rH2O by prediction equation (equation-derived WI). Food records were employed to determine WI (food record-derived WI).

RESULTS

Only DLW-derived WI showed no significant differences compared to reference in both sexes (females: 2 mL/day, p = 0.183; males: -4 mL/day, p = 0.118). 2H-derived WI showed significant but small differences (females: 23 mL/day, p = 0.001; males: 32 mL/day, p < 0.001) while food record-derived WI showed the largest differences (females: -924 mL/day, p < 0.001; males: -1504 mL/day, p < 0.001). DLW-derived and 2H-derived WI showed good performance [r2 > 0.987 and concordance correlation coefficient (CCC) > 0.993], while food record-derived WI showed poor performance [r2 < 0.031 and CCC < 0.133)].

CONCLUSION

Although some alternative approaches provide adequate estimates, DLW- and 2H-derived WI are the only valid methods to determine WI in our sample of competitive athletes. These approaches are less costly and could contribute to the development of WI guidelines for athletes. Food records underestimate WI, but evidence-based recommendations could reduce misrecordings.

Identification of sensitive periods of weight status transition over the lifespan in Chinese population

BACKGROUND

The prevalence of high body mass index (BMI) is increasing in both children and adults worldwide. However, it is unclear whether vulnerabilities to maintenance and transition of weight status vary throughout the lifespan.

OBJECTIVE

We aimed to characterize dynamic transitions of weight statuses across different life stages and to identify the sensitive periods for maintenance, onset, and resolution of obesity.

METHODS

This longitudinal study included a total of 23,179 participants aged 6-80 years with 95,994 BMI measurements from the China Health and Nutrition Survey 1989-2015. To examine the heterogeneity in transitions of weight statuses across different life stages, we divided participants into 8 sub-cohorts based on baseline ages by 10-year intervals, i.e., 6-10 years, 11-20 years, 21-30 years, 31-40 years, 41-50 years, 51-60 years, 61-70 years, and 71-80 years. We estimated the probabilities of transitioning between weight statuses at a given follow-up year by baseline age using generalized linear mixed-effects models.

RESULTS

The predicted prevalence of obesity decreased from 6 years, bottomed at around 20 years, increased thereafter, peaked at around 55 years, and then decreased gradually. In general, participants with underweight had lower probabilities of maintaining the same status compared to those with normal weight, overweight, or obesity for all age groups. For 10-year follow-up, individuals aged 21-30 years had the highest probabilities of transitioning from normal weight to obesity and transitioning from overweight to obesity compared to those in other age groups. Individuals aged 6-20 years had the highest probabilities of transitioning from obesity to normal weight and transitioning from overweight to normal weight. Individuals in all adult age groups had higher probabilities of maintaining obesity status than children and adolescents.

CONCLUSIONS

Young adulthood is the most sensitive period for obesity onset, whereas childhood and adolescence are the most sensitive periods for obesity resolution. The findings suggest the heterogeneity of susceptibilities to weight status transitions across different life stages and highlight the importance of the development of age-appropriate approaches for the prevention and intervention of obesity.