Plant genome evolution in the genus Eucalyptus driven by structural rearrangements that promote sequence divergence.

Genomes have a highly organized architecture (nonrandom organization of functional and nonfunctional genetic elements within chromosomes) that is essential for many biological functions, particularly, gene expression and reproduction. Despite the need to conserve genome architecture, a high level of structural variation has been observed within species. As species separate and diverge, genome architecture also diverges, becoming increasingly poorly conserved as divergence time increases. However, within plant genomes, the processes of genome architecture divergence are not well described. Here we use long-read sequencing and de novo assembly of 33 phylogenetically diverse, wild and naturally evolving Eucalyptus species, covering 1-50 million years of diverging genome evolution to measure genome architectural conservation and describe architectural divergence. The investigation of these genomes revealed that following lineage divergence genome architecture is highly fragmented by rearrangements. As genomes continue to diverge, the accumulation of mutations and subsequent divergence beyond recognition of rearrangements becomes the primary driver of genome divergence. The loss of syntenic regions also contribute to genome divergence, but at a slower pace than rearrangements. We hypothesise that duplications and translocations are potentially the greatest contributors to Eucalyptus genome divergence.

Current Use and Barriers to Point-of-Care Ultrasound in Rheumatology: A National Survey of VA Medical Centers.

INTRODUCTION: Point-of-care ultrasound (POCUS) can assist rheumatologists in monitoring disease activity, establishing diagnoses, and guiding procedural interventions. POCUS use has been increasing, but little is known about current use and barriers among rheumatologists. The purpose of this study was to characterize current POCUS use, training needs, and barriers to use among rheumatologists in practice. METHODS: A prospective observational study of all Veterans Affairs (VA) medical centers was conducted using a web-based survey sent to all chiefs of staff and rheumatology chiefs about current POCUS use, training needs, barriers, and policies. RESULTS: All chiefs of staff (n = 130) and rheumatology chiefs at VA medical centers (n = 95) were surveyed with 100% and 84% response rates, respectively. The most common diagnostic POCUS applications were evaluation of synovitis, joint effusion, tendinopathies, bursitis, and rotator cuff. The most common procedural applications were arthrocentesis and joint, bursa, and tendon injection. Most rheumatology chiefs (69%) expressed interest in training for their group. The most common barriers to POCUS use were lack of trained providers (68%), funding for training (54%), training opportunities (38%), funding for travel (38%), and ultrasound equipment (31%). Lack of POCUS infrastructure was common, and few facilities had POCUS policies (20%), image archiving (25%), or quality assurance processes (6%). CONCLUSION: Currently, half of rheumatology groups use diagnostic and procedural ultrasound applications. Most rheumatology groups desire training, and lack of training and equipment were the most common barriers to ultrasound use. Deliberate investment is needed in ultrasound training and infrastructure for systematic adoption of POCUS in rheumatology. Graphical Abstract available for this article. TRIAL REGISTRATION: NCT03296280.

Australasian Malignant PLeural Effusion (AMPLE)-4 trial: study protocol for a multi-centre randomised trial of topical antibiotics prophylaxis for infections of indwelling pleural catheters.

BACKGROUND: Malignant pleural effusion (MPE) is a debilitating condition as it commonly causes disabling breathlessness and impairs quality of life (QoL). Indwelling pleural catheter (IPC) offers an effective alternative for the management of MPE. However, IPC-related infections remain a significant concern and there are currently no long-term strategies for their prevention. The Australasian Malignant PLeural Effusion (AMPLE)-4 trial is a multicentre randomised trial that evaluates the use of topical mupirocin prophylaxis (vs no mupirocin) to reduce catheter-related infections in patients with MPE treated with an IPC. METHODS: A pragmatic, multi-centre, open-labelled, randomised trial. Eligible patients with MPE and an IPC will be randomised 1:1 to either regular topical mupirocin prophylaxis or no mupirocin (standard care). For the interventional arm, topical mupirocin will be applied around the IPC exit-site after each drainage, at least twice weekly. Weekly follow-up via phone calls or in person will be conducted for up to 6 months. The primary outcome is the percentage of patients who develop an IPC-related (pleural, skin, or tract) infection between the time of catheter insertion and end of follow-up period. Secondary outcomes include analyses of infection (types and episodes), hospitalisation days, health economics, adverse events, and survival. Subject to interim analyses, the trial will recruit up to 418 participants. DISCUSSION: Results from this trial will determine the efficacy of mupirocin prophylaxis in patients who require IPC for MPE. It will provide data on infection rates, microbiology, and potentially infection pathways associated with IPC-related infections. ETHICS AND DISSEMINATION: Sir Charles Gairdner and Osborne Park Health Care Group Human Research Ethics Committee has approved the study (RGS0000005920). Results will be published in peer-reviewed journals and presented at scientific conferences. TRIAL REGISTRATION: Australia New Zealand Clinical Trial Registry ACTRN12623000253606. Registered on 9 March 2023.

The plasma metabolome is associated with preservation of physiological function following lifelong aerobic exercise in mice.

Declines in physiological function with aging are strongly linked to age-related diseases. Lifelong voluntary aerobic exercise (LVAE) preserves physiological function with aging, possibly by increasing cellular quality control processes, but the circulating molecular transducers mediating these processes are incompletely understood. The plasma metabolome may predict biological aging and is impacted by a single bout of aerobic exercise. Here, we conducted an ancillary analysis using plasma samples, and physiological function data, from previously reported studies of LVAE in male C57BL/6N mice randomized to LVAE (wheel running) or sedentary (SED) (n = 8-9/group) to determine if LVAE alters the plasma metabolome and whether these changes correlated with preservation of physiological function with LVAE. Physical function (grip strength, coordination, and endurance) was assessed at 3 and 18 months of age; vascular endothelial function and the plasma metabolome were assessed at 19 months. Physical function was preserved (%decline; mean ± SEM) with LVAE vs SED (all p < 0.05)-grip strength, 0.4 ± 1.7% vs 12 ± 4.0%; coordination, 10 ± 4% vs 73 ± 10%; endurance, 1 ± 15% vs 61 ± 5%. Vascular endothelial function with LVAE (88.2 ± 2.0%) was higher than SED (79.1 ± 2.5%; p = 0.03) and similar to the young controls (91.4 ± 2.9%). Fifteen metabolites were different with LVAE compared to SED (FDR < 0.05) and correlated with the preservation of physiological function. Plasma spermidine, a polyamine that increases cellular quality control (e.g., autophagy), correlated with all assessed physiological indices. Autophagy (LC3A/B abundance) was higher in LVAE skeletal muscle compared to SED (p < 0.01) and inversely correlated with plasma spermidine (r = - 0.5297; p = 0.054). These findings provide novel insight into the circulating molecular transducers by which LVAE may preserve physiological function with aging.

Association between preschooler outdoor play and home yard vegetation as measured by high resolution imagery: Findings from the PLAYCE study.

Outdoor play in the home yard is an important source of physical activity for many preschoolers. This study investigated if home yard size and vegetation are related to preschooler outdoor play time. High-resolution remotely sensed data were used to distinguish between types of vegetation coverage in the home yard. Shrub and tree cover, and yard size, were positively associated with outdoor play. Following stratification by socio-economic status (SES - parent education), only tree cover was positively associated with preschooler outdoor play in low SES households. All types of vegetation cover were positively associated with preschooler outdoor play in higher SES households. This study highlights the importance of larger yard sizes and higher levels of vegetation for facilitating outdoor play in preschoolers.

Longitudinal effects of dog ownership, dog acquisition, and dog loss on children's movement behaviours: findings from the PLAYCE cohort study.

INTRODUCTION: Regular physical activity is important for children's physical and mental health, yet many children do not achieve recommended amounts of physical activity. Dog ownership has been associated with increased physical activity in children, however, there have been no longitudinal studies examining this relationship. This study used data from the Play Spaces and Environments for Children's Physical Activity (PLAYCE) cohort study to examine the longitudinal effects of dog ownership status on children's movement behaviours. METHODS: Change in dog ownership from preschool (wave 1, age 2-5) to fulltime school (wave 2, age 5-7) was used as a natural experiment with four distinct dog ownership groups: continuing non-dog owners (n = 307), continuing dog owners (n = 204), dog acquired (n = 58), and dog loss (n = 31; total n = 600). Daily movement behaviours, including physical activity, sedentary time, sleep, and screen time, were measured using accelerometry and parent-report surveys. Differences between groups over time and by sex were tested using linear mixed effects regression models. RESULTS: Girls who acquired a dog increased their light intensity activities and games by 52.0 min/day (95%CI 7.9, 96.0) and girls who lost a dog decreased their light intensity activities and games by 62.1 min/day (95%CI -119.3, -4.9) compared to no change among non-dog owners. Girls and boys who acquired a dog increased their unstructured physical activity by 6.8 (95%CI 3.2, 10.3) and 7.1 (95%CI 3.9, 10.3) occasions/week, compared to no changes among non-dog owners. Girls and boys who lost a dog reduced their unstructured physical activity by 10.2 (95%CI -15.0, -5.3) and 7.7 (95%CI -12.0, -3.5) occasions/week. Girls who lost a dog decreased their total physical activity by 46.3 min/day (95%CI -107.5, 14.8) compared to no change among non-dog owners. Continuing dog ownership was typically not associated with movement behaviours. Dog ownership group was not associated with changes in sleep and had mixed associations with screen time. CONCLUSION: The positive influence of dog ownership on children's physical activity begins in early childhood and differs by child sex. Further research should examine the specific contributions dog-facilitated physical activity makes to children's overall physical activity, including the intensity and duration of dog walking and play.

Young children's use of blue spaces and the impact on their health, development and environmental awareness: A qualitative study from parents' perspectives.

ISSUE ADDRESSED: This study examined how families with young children access and use different types of blue spaces and the health and development benefits, and potential negative effects. METHODS: Parents(n = 25) of young children across four coastal communities in Western Australia were recruited via purposive sampling to participate in interviews. A generic qualitative study design grounded in the pragmatism paradigm was utilised. RESULTS: Beaches were the most frequently used blue space for families all year around, however families did not necessarily attend their closest beach. This appears due to certain beach features making them more or less attractive for use regardless of the distance from home. Parents perceived blue spaces as health promoting due to the increased physical activity children did in and around these spaces. They also reported blue spaces could be positive for child development, contributing to the development of identity. Blue spaces were also perceived to promote children's environmental awareness and environmentally friendly behaviours. However, blue spaces could also be potentially risky environments for families with young children. CONCLUSIONS: The findings highlight blue spaces are an important setting for supporting children's health, development and environmental consciousness. SO WHAT?: It is important to protect natural outdoor environments such as blue spaces for future generations. The findings can be used by governments and policy makers to improve the quality (features and amenities) of blue spaces and positively impact how often families (including those with dogs) use blue spaces and the benefits they experience.

Exertional heat stroke causes long-term skeletal muscle epigenetic reprogramming, altered gene expression, and impaired satellite cell function in mice.

The effect of exertional heat stroke (EHS) exposure on skeletal muscles is incompletely understood. Muscle weakness is an early symptom of EHS but is not considered a major target of multiorgan injury. Previously, in a preclinical mouse model of EHS, we observed the vulnerability of limb muscles to a second EHS exposure, suggesting hidden processes contributing to declines in muscle resilience. Here, we evaluated the possible molecular origins of EHS-induced declines in muscle resilience. Female C57BL/6 mice [total n = 56; 28/condition, i.e., EHS and exercise control (EXC)] underwent forced wheel running at 37.5°C/40% relative humidity until symptom limitation (unconsciousness). EXC mice exercised identically at room temperature (22-23°C). After 1 mo of recovery, the following were assessed: 1) specific force and caffeine-induced contracture in soleus (SOL) and extensor digitorum longus (EDL) muscles; 2) transcriptome and DNA methylome responses in gastrocnemius (GAST); and 3) primary satellite cell function (proliferation and differentiation). There were no differences in specific force in either SOL or EDL from EXC. Only EHS solei exhibited lower caffeine sensitivity. EHS GAST exhibited higher RNA expression of genes encoding structural proteins of slow fibers, heat shock proteins, and myogenesis. A total of ∼2,500 differentially methylated regions of DNA that could potentially affect many cell functions were identified. Primary satellite cells exhibited suppressed proliferation rates but normal differentiation responses. Results demonstrate long-term changes in skeletal muscles 1 mo after EHS that could contribute to declines in muscle resilience. Skeletal muscle may join other, more recognized tissues considered vulnerable to long-term effects of EHS.NEW & NOTEWORTHY Exertional heat stroke (EHS) in mice induces long-term molecular and functional changes in limb muscle that could reflect a loss of "resilience" to further stress. The phenotype was characterized by altered caffeine sensitivity and suppressed satellite cell proliferative potential. This was accompanied by changes in gene expression and DNA methylation consistent with ongoing muscle remodeling and stress adaptation. We propose that EHS may induce a prolonged vulnerability of skeletal muscle to further stress or injury.

Excess Deaths Associated with Rheumatic Heart Disease, Australia, 2013-2017.

During 2013-2017, the mortality rate ratio for rheumatic heart disease among Indigenous versus non-Indigenous persons in Australia was 15.9, reflecting health inequity. Using excess mortality methods, we found that deaths associated with rheumatic heart disease among Indigenous Australians were probably substantially undercounted, affecting accuracy of calculations based solely on Australian Bureau of Statistics data.

Dietary Vitamin K1 Intake and Incident Aortic Valve Stenosis.

BACKGROUND: Leaflet calcification contributes to the development and progression of aortic valve stenosis. Vitamin K activates inhibitors of vascular calcification and may modulate inflammation and skeletal bone loss. Therefore, we aimed to determine whether higher dietary intakes of vitamin K1 are associated with a lower incidence of aortic stenosis. METHODS: In the Danish Diet, Cancer and Health study, participants aged 50 to 64 years completed a 192-item food frequency questionnaire at baseline, from which habitual intakes of vitamin K1 were estimated. Participants were prospectively followed using linkage to nationwide registers to determine incident aortic valve stenosis (primary outcome) and aortic stenosis with subsequent complications (aortic valve replacement, heart failure, or cardiovascular disease-related mortality; secondary outcome). RESULTS: In 55 545 participants who were followed for a maximum of 21.5 years, 1085 were diagnosed with aortic stenosis and 615 were identified as having subsequent complications. Participants in the highest quintile of vitamin K1 intake had a 23% lower risk of aortic stenosis (hazard ratio, 0.77 [95% CI, 0.63-0.94]) and a 27% lower risk of aortic stenosis with subsequent complications (hazard ratio, 0.73 [95% CI, 0.56-0.95]), compared with participants in the lowest quintile after adjusting for demographics and cardiovascular risk factors. CONCLUSIONS: In this study, a high intake of vitamin K1-rich foods was associated with a lower incidence of aortic stenosis and a lower risk of aortic stenosis with subsequent complications.

The art of aging well: a study of the relationship between recreational arts engagement, general health and mental wellbeing in cohort of Australian older adults.

Introduction: Evidence of the benefits of arts engagement to community wellbeing has been mounting since the 1990s. However, large scale, quantitative, epidemiological studies of the "arts-healthy aging" relationship, or the types of arts older adults voluntarily choose to engage in as part of their everyday life, for enjoyment, entertainment or as a hobby (vs. therapy or interventions) are limited. The aims of this study were to describe older adult recreational arts engagement via the Busselton Healthy Ageing Study (BHAS) cohort, and to determine if there was an association between arts engagement, general health and mental wellbeing. Methods: Overall, 2,843 older adults (born 1946-1964) from the BHAS cohort (n = 5,107) who had completed a supplementary arts survey (n = 3,055, 60%) and had data on required variables were included in this study (93% of those eligible). The dependent variable was general health (SF12) and subjective mental wellbeing (Warwick-Edinburgh Mental Wellbeing Scale, WEMWBS). The independent variable was hours engaged in recreational arts in the last 12 months. A descriptive analysis followed by a linear regression analysis was conducted. Results: The prevalence of recreational arts engagement in the last 12 months was 85% (mean = 132 h/year). Older adults engaged in the arts in a number of ways including attending events (79%), actively participating/making art (40%), as an arts society/club/organization member (20%), by learning about the arts (13%) or by volunteering/working in the arts (non-professional, 11%). When general health was assessed via the SF12, the average physical component score (PCS) was 50.1 (SD 8.9) and the average mental component score (MCS) was 53.6 (SD 8.3). When mental wellbeing was assessed, the average WEMWBS score was 54.9 (SD = 8.6). After adjustment for 12 demographic and lifestyle covariates, it was found that older adults who engaged in any recreational arts in the last 12 months had significantly higher WEMWBS scores and higher SF12 physical component scores than those who did not engage in the arts (0 h/year). Discussion: Evidence of an arts-health relationship was found in this study. The suitability of the arts as a population based, healthy aging strategy to influence the mental wellbeing and general health of older adults should be investigated further.

Discovery of Modified Metabolites, Secondary Metabolites, and Xenobiotics by Structure-Oriented LC-MS/MS.

Exogenous compounds and metabolites derived from therapeutics, microbiota, or environmental exposures directly interact with endogenous metabolic pathways, influencing disease pathogenesis and modulating outcomes of clinical interventions. With few spectral library references, the identification of covalently modified biomolecules, secondary metabolites, and xenobiotics is a challenging task using global metabolomics profiling approaches. Numerous liquid chromatography-coupled mass spectrometry (LC-MS) small molecule analytical workflows have been developed to curate global profiling experiments for specific compound groups of interest. These workflows exploit shared structural moiety, functional groups, or elemental composition to discover novel and undescribed compounds through nontargeted small molecule discovery pipelines. This Review introduces the concept of structure-oriented LC-MS discovery methodology and aims to highlight common approaches employed for the detection and characterization of covalently modified biomolecules, secondary metabolites, and xenobiotics. These approaches represent a combination of instrument-dependent and computational techniques to rapidly curate global profiling experiments to detect putative ions of interest based on fragmentation patterns, predictable phase I or phase II metabolic transformations, or rare elemental composition. Application of these methods is explored for the detection and identification of novel and undescribed biomolecules relevant to the fields of toxicology, pharmacology, and drug discovery. Continued advances in these methods expand the capacity for selective compound discovery and characterization that promise remarkable insights into the molecular interactions of exogenous chemicals with host biochemical pathways.

Making a SmartStart for peanut introduction to support food allergy prevention guidelines for infants.

Background: Food allergy affects up to 10% of Australian infants. It was hypothesized that if parents follow the Australasian Society of Clinical Immunology and Allergy guidelines, Australian food allergy rates may stabilize or decline. Objective: This project aimed to determine whether SmartStartAllergy influenced parental introduction of peanut by age 12 months, including in high-risk infants. Methods: SmartStartAllergy integrates with general practice management software to send text messages to parents via participating general practices. The intervention group participants were sent text messages when their child was aged 6, 9, and 12 months; the control group participants were parents of 12-month-old infants. When their child was aged 12 months, all participants completed a questionnaire regarding eczema and family history of atopy. Infants with severe eczema and/or a family history of atopy were considered high-risk. Results: Between 21 September 2018 and 26 April 2022, a total of 29,092 parents were enrolled in SmartStartAllergy as intervention (n = 18,090) and control (n = 11,002) group members The intervention group was more likely to introduce peanut by 12 months (crude odds ratio = 5.18; P < .0001; 95% CI = 4.35-6.16). After adjustment for the infants' level of risk and family history of atopy and food allergy, the intervention group was more likely to introduce peanut by 12 months of age (adjusted odds ratio = 5.34; P < .01; 95% CI = 4.48-6.37). Conclusion: SmartStartAllergy appears to be an effective tool for encouraging parental introduction of peanut. The ability to provide parents with credible allergy prevention information, along with the capacity to collect simple responses via text along with additional information via an online questionnaire, make this a useful public health tool.

Structure-based design of nanobodies that inhibit seeding of Alzheimer's patient-extracted tau fibrils.

Despite much effort, antibody therapies for Alzheimer's disease (AD) have shown limited efficacy. Challenges to the rational design of effective antibodies include the difficulty of achieving specific affinity to critical targets, poor expression, and antibody aggregation caused by buried charges and unstructured loops. To overcome these challenges, we grafted previously determined sequences of fibril-capping amyloid inhibitors onto a camel heavy chain antibody scaffold. These sequences were designed to cap fibrils of tau, known to form the neurofibrillary tangles of AD, thereby preventing fibril elongation. The nanobodies grafted with capping inhibitors blocked tau aggregation in biosensor cells seeded with postmortem brain extracts from AD and progressive supranuclear palsy (PSP) patients. The tau capping nanobody inhibitors also blocked seeding by recombinant tau oligomers. Another challenge to the design of effective antibodies is their poor blood-brain barrier (BBB) penetration. In this study, we also designed a bispecific nanobody composed of a nanobody that targets a receptor on the BBB and a tau capping nanobody inhibitor, conjoined by a flexible linker. We provide evidence that the bispecific nanobody improved BBB penetration over the tau capping inhibitor alone after intravenous administration in mice. Our results suggest that the design of synthetic antibodies that target sequences that drive protein aggregation may be a promising approach to inhibit the prion-like seeding of tau and other proteins involved in AD and related proteinopathies.

Higher Habitual Dietary Intakes of Flavanols and Anthocyanins Differentially Associate with Lower Incidence of Ischemic Stroke Subtypes-A Follow-Up Analysis.

BACKGROUND: We previously reported that habitual consumption of dietary flavanol oligomers + polymers and anthocyanins is associated with a lower risk of ischemic stroke. However, no studies have investigated their relationship with ischemic stroke subtypes. OBJECTIVES: In this follow-up analysis, we aimed to examine the association of flavanol oligomers + polymers and anthocyanin intake with ischemic stroke subtypes, including the following: 1) large-artery atherosclerosis, 2) cardioembolism, 3) small-vessel occlusion, 4) other determined etiology, and 5) undetermined etiology. METHODS: Participants (n = 55,094) from the Danish Diet, Cancer, and Health Study were followed up for <16 y for first-time ischemic stroke events, which were classified according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria. Intakes of flavanol oligomers + polymers and anthocyanins were calculated from food frequency questionnaires using the Phenol-Explorer database, and their relationships with ischemic stroke subtypes were investigated using restricted cubic splines within Cox proportional hazards models. After multivariable adjustment, higher habitual intakes (quintile 5 compared with quintile 1) of flavanol oligomers + polymers and anthocyanins were associated with a lower risk of specific ischemic stroke subtypes, including large-artery atherosclerosis [flavanol oligomers + polymers, hazard ratio {HR} (95% confidence interval {CI}): 0.64 (0.47, 0.87)], cardioembolism [anthocyanins, HR (95% CI): 0.45 (0.25, 0.82)], and small-vessel occlusion [flavanol oligomers + polymers, HR (95% CI): 0.65 (0.54, 0.80); anthocyanins, HR (95% CI): 0.79 (0.64, 0.97)], but not stroke of other determined or undetermined etiology. CONCLUSIONS: Higher habitual intakes of flavanols and anthocyanins are differentially associated with a lower risk of ischemic stroke from atherosclerosis and/or cardioembolism but not with other subtypes.

Point-of-care ultrasound in geriatrics: a national survey of VA medical centers.

BACKGROUND: Point-of-care ultrasound (POCUS) can aid geriatricians in caring for complex, older patients. Currently, there is limited literature on POCUS use by geriatricians. We conducted a national survey to assess current POCUS use, training desired, and barriers among Geriatrics and Extended Care ("geriatric") clinics at Veterans Affairs Medical Centers (VAMCs). METHODS: We conducted a prospective observational study of all VAMCs between August 2019 and March 2020 using a web-based survey sent to all VAMC Chiefs of Staff and Chiefs of geriatric clinics. RESULTS: All Chiefs of Staff (n=130) completed the survey (100% response rate). Chiefs of geriatric clinics ("chiefs") at 76 VAMCs were surveyed and 52 completed the survey (68% response rate). Geriatric clinics were located throughout the United States, mostly at high-complexity, urban VAMCs. Only 15% of chiefs responded that there was some POCUS usage in their geriatric clinic, but more than 60% of chiefs would support the implementation of POCUS use. The most common POCUS applications used in geriatric clinics were the evaluation of the bladder and urinary obstruction. Barriers to POCUS use included a lack of trained providers (56%), ultrasound equipment (50%), and funding for training (35%). Additionally, chiefs reported time utilization, clinical indications, and low patient census as barriers. CONCLUSIONS: POCUS has several potential applications for clinicians caring for geriatric patients. Though only 15% of geriatric clinics at VAMCs currently use POCUS, most geriatric chiefs would support implementing POCUS use as a diagnostic tool. The greatest barriers to POCUS implementation in geriatric clinics were a lack of training and ultrasound equipment. Addressing these barriers systematically can facilitate implementation of POCUS use into practice and permit assessment of the impact of POCUS on geriatric care in the future.

Factors Associated With Circulating Sex Hormones in Men : Individual Participant Data Meta-analyses.

BACKGROUND: Various factors modulate circulating testosterone in men, affecting interpretation of testosterone measurements. PURPOSE: To clarify factors associated with variations in sex hormone concentrations. DATA SOURCES: Systematic literature searches (to July 2019). STUDY SELECTION: Prospective cohort studies of community-dwelling men with total testosterone measured using mass spectrometry. DATA EXTRACTION: Individual participant data (IPD) (9 studies; n = 21 074) and aggregate data (2 studies; n = 4075). Sociodemographic, lifestyle, and health factors and concentrations of total testosterone, sex hormone-binding globulin (SHBG), luteinizing hormone (LH), dihydrotestosterone, and estradiol were extracted. DATA SYNTHESIS: Two-stage random-effects IPD meta-analyses found a nonlinear association of testosterone with age, with negligible change among men aged 17 to 70 years (change per SD increase about the midpoint, -0.27 nmol/L [-7.8 ng/dL] [CI, -0.71 to 0.18 nmol/L {-20.5 to 5.2 ng/dL}]) and decreasing testosterone levels with age for men older than 70 years (-1.55 nmol/L [-44.7 ng/dL] [CI, -2.05 to -1.06 nmol/L {-59.1 to -30.6 ng/dL}]). Testosterone was inversely associated with body mass index (BMI) (change per SD increase, -2.42 nmol/L [-69.7 ng/dL] [CI, -2.70 to -2.13 nmol/L {-77.8 to -61.4 ng/dL}]). Testosterone concentrations were lower for men who were married (mean difference, -0.57 nmol/L [-16.4 ng/dL] [CI, -0.89 to -0.26 nmol/L {-25.6 to -7.5 ng/dL}]); undertook at most 75 minutes of vigorous physical activity per week (-0.51 nmol/L [-14.7 ng/dL] [CI, -0.90 to -0.13 nmol/L {-25.9 to -3.7 ng/dL}]); were former smokers (-0.34 nmol/L [-9.8 ng/dL] [CI, -0.55 to -0.12 nmol/L {-15.9 to -3.5 ng/dL}]); or had hypertension (-0.53 nmol/L [-15.3 ng/dL] [CI, -0.82 to -0.24 nmol/L {-23.6 to -6.9 ng/dL}]), cardiovascular disease (-0.35 nmol/L [-10.1 ng/dL] [CI, -0.55 to -0.15 nmol/L {-15.9 to -4.3 ng/dL}]), cancer (-1.39 nmol/L [-40.1 ng/dL] [CI, -1.79 to -0.99 nmol/L {-51.6 to -28.5 ng/dL}]), or diabetes (-1.43 nmol/L [-41.2 ng/dL] [CI, -1.65 to -1.22 nmol/L {-47.6 to -35.2 ng/dL}]). Sex hormone-binding globulin was directly associated with age and inversely associated with BMI. Luteinizing hormone was directly associated with age in men older than 70 years. LIMITATION: Cross-sectional analysis, heterogeneity between studies and in timing of blood sampling, and imputation for missing data. CONCLUSION: Multiple factors are associated with variation in male testosterone, SHBG, and LH concentrations. Reduced testosterone and increased LH concentrations may indicate impaired testicular function after age 70 years. Interpretation of individual testosterone measurements should account particularly for age older than 70 years, obesity, diabetes, and cancer. PRIMARY FUNDING SOURCE: Medical Research Future Fund, Government of Western Australia, and Lawley Pharmaceuticals. (PROSPERO: CRD42019139668).