Quadratic Age Terms Research Articles

The impact of multimorbidity on cardiac remodelling in the UK Biobank

Abstract Background/Introduction Previous work has suggested that multimorbidity is associated with higher all-cause mortality and cardiovascular mortality in the UK Biobank (UKB). The impact of multimorbidity on cardiac remodelling as measured by cardiovascular magnetic resonance (CMR) has not been studied in large cohorts. Purpose To determine if CMR biomarkers act as surrogates for adverse cardiovascular outcomes in multimorbidity. Method We analysed 44957 UKB participants who had CMR. Self-reported cancer (UKB field ID 20001) and non-cancer illnesses (UKB field ID 20002) were used to calculate comorbidity count with multi-morbidity defined as 2 or more illnesses. The predictive value of comorbidity count (exposure counts measured in quintiles) on CMR traits (outcomes) was evaluated using a univariable and multivariable generalised linear model. Covariates included sex, age, BMI, smoking status, regular alcohol intake, and the Townsend deprivation index, a measure of socioeconomic deprivation. The first model utilised univariable regression without covariates with subsequent iterations including age and sex and then all covariates. An interaction term was included for age and sex and a quadratic term for age in the models. CMR outcome measures were indexed left ventricular mass (LVM), indexed left ventricular end diastolic volume (LVEDV), indexed left ventricular end systolic volume (LVESV), indexed left ventricular stroke volume (LVSV), left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), and indexed maximal left atrial volume (LA). The absolute value of GLS was used in the regression models. Variance inflation factor testing was used to check for collinearity. Analyses were completed using R v4.1.1. Results Median comorbidity count was 2. The burden of long-term conditions in this population of European ancestry with largely healthy individuals is lower than in other large population cohorts. Table 1 summarises multivariable analyses for comorbidity count, LVM and GLS. Due to high collinearity relating to age in the model, we centred age around the mean. LVM was higher with multimorbidity (top quintile Beta 0.63 (95% CI 0.23 to 1.04), P = 2.21x10-03). GLS was lower with multimorbidity (top quintile Beta -0.29 (95%CI -0.42 to 0.16), P = 8.10x10-6). LA volume was lower with multimorbidity (top quintile Beta -0.63(95% CI -1.22 to 0.04), P = 3.53 x 10-2). LVEF and other volume measures were not associated with multimorbidity. Conclusion Multimorbidity in this large cohort was associated with adverse cardiac structural and functional remodelling on CMR. These include a lower global longitudinal strain and higher LV mass.

Patterns of ultra-processed foods consumption throughout childhood and trajectories of growth and adiposity

Background & aimsUltra-processed foods (UPF) consumption has been associated with unhealthy outcomes. However, the literature lacks robust longitudinal studies considering its cumulative effect, particularly in young populations. This study aimed to evaluate the relationship between UPF consumption patterns throughout childhood with growth and adiposity trajectories. MethodsGeneration XXI population-based birth cohort (Porto, Portugal) participants were included. Food frequency questionnaire items at 4, 7 and 10 years were classified according to the processing degree using NOVA. UPF consumption patterns based on total quantity were identified using a probabilistic Gaussian mixture model using participants with complete data and predicting for the total sample (n=8647). To assess whether the outcome trajectories from 4 to 13 years [body weight (kg), height (cm), body mass index (BMI) z-score, waist circumference (WC) (cm) and fat mass (FM) (%)] depend on UPF patterns, a mixed-effects model with linear and quadratic terms for age adjusted for confounders was used. Participants with at least 2 measurements at 4, 7, 10 or 13 years were included in this study (n range: 5885-6272). ResultsFour UPF consumption patterns were identified: constantly lower consumption (15.4%), constantly intermediate consumption (56.4%), transition from low to high consumption (11.2%), and constantly higher consumption (17.1%). Compared to the constantly lower UPF consumption, the constantly higher consumption pattern was associated with greater acceleration in body weight (β: 0.119; 95%CI: 0.027;0.212), BMI z-score (β: 0.014; 95%CI: 0.004;0.023), WC (β: 0.232; 95%CI: 0.144;0.319) and FM% (β: 0.200; 95%CI: 0.092;0.308) and with lower acceleration in height (β: -0.063; 95%CI: -0.111;-0.015). The constantly intermediate UPF consumption pattern was associated with greater acceleration in body weight (β: 0.123; 95%CI: 0.043;0.203), WC (β: 0.120; 95%CI: 0.045;0.195) and FM% (β: 0.146; 95%CI: 0.054;0.238). ConclusionConstantly higher and constantly intermediate UPF consumption throughout childhood were associated with worse growth and adiposity trajectories until adolescence.

A pre-longitudinal screen of performance in an integrated assessment of throwing and catching competence

ABSTRACT Background: The ability to adapt motor skill performance to a variety of conditions is vital to success in physical activity settings. Valid and reliable measurements of motor competence (MC) are critical for understanding its impact on physical health. Many widely used MC assessments evaluate the performance of isolated motor skills, place performers in highly standardized environments, and limit opportunities to adapt performance. Consequently, evaluations of motor skill performance using these tools may not adequately differentiate motor skill levels. Assessing MC in more dynamic performance contexts may enhance the utility of MC measures. Purpose: The purpose of this study was to examine the developmental validity of scores on a combined throwing and catching assessment. Data Collection and Analysis: Data were collected on a convenience sample (n = 873, n female = 320, age = 14.7 years ± 4.2). Participants threw a regulation tennis ball against a wall from a distance three times their standing height and caught it as many times as possible in 30 s. Performers were free to use any throwing pattern (e.g. over/underarm) or task strategy (e.g. speed, trajectory of ball, ball bouncing, one- or two-handed catch). The highest number of catches between two 30-second trials was used for analysis. Descriptive statistics were calculated for the total sample and for males and females separately. Pearson correlations were used to evaluate the relationship between throw-catch assessment (TCA) scores and age. We evaluated the relationship between TCA score, sex, and age via hierarchical regression with TCA score as the dependent variable using three models: (1) Participant sex as the sole predictor, (2) sex and age as predictors, and (3) sex, age, and the quadratic term for age (age2). Additionally, we evaluated the reliability of scores on TCA assessment trials via intraclass correlations (ICCs) using a two-way, fixed effects model. Results: The mean TCA score was 11.34 (± 5.44; M females = 9.18 ± 4.80, M males = 12.59 ± 5.40). Strong relationships were observed between TCA score and age (r = .743, r females = .698, r males = .746; all significant at p < .001). Significant increases in model fit were observed at each stage of the hierarchical regression (Model 1: R 2 = .091, p < .01; Model 2: ΔR 2 = .484, p < .01; Model 3: ΔR 2 = .009, p < .01), with the final model indicating significant effects for sex (β male = 1.95, p < .01), age (β = 2.01, p < .01) and age2 (β = –.04, p < .01) on TCA score (R 2 = .584, F 3,869 = 406.7, p < .001). Finally, there was good reliability between scores on the two TCA trials (ICC = .875, F 872,873 = 14.97, p < .001). Discussion: These data provide preliminary evidence for the developmental validity of the TCA across childhood to young adulthood. The ability to differentiate skill levels across a wide age-range can enhance the ability to track MC across the lifespan and better understand the relationship between covariates of MC across the lifespan. These data provide support for a MC assessment that can be used by researchers and practitioners to evaluate throwing and catching skill in a swift and ecologically valid way.

Association of brain tissue cerebrospinal fluid fraction with age in healthy cognitively normal adults.

Our objective was to apply multi-compartment T2 relaxometry in cognitively normal individuals aged 20-80 years to study the effect of aging on the parenchymal CSF fraction (CSFF), a potential measure of the subvoxel CSF space. A total of 60 volunteers (age range, 22-80 years) were enrolled. Voxel-wise maps of short-T2 myelin water fraction (MWF), intermediate-T2 intra/extra-cellular water fraction (IEWF), and long-T2 CSFF were obtained using fast acquisition with spiral trajectory and adiabatic T2prep (FAST-T2) sequence and three-pool non-linear least squares fitting. Multiple linear regression analyses were performed to study the association between age and regional MWF, IEWF, and CSFF measurements, adjusting for sex and region of interest (ROI) volume. ROIs include the cerebral white matter (WM), cerebral cortex, and subcortical deep gray matter (GM). In each model, a quadratic term for age was tested using an ANOVA test. A Spearman's correlation between the normalized lateral ventricle volume, a measure of organ-level CSF space, and the regional CSFF, a measure of tissue-level CSF space, was computed. Regression analyses showed that there was a statistically significant quadratic relationship with age for CSFF in the cortex (p = 0.018), MWF in the cerebral WM (p = 0.033), deep GM (p = 0.017) and cortex (p = 0.029); and IEWF in the deep GM (p = 0.033). There was a statistically highly significant positive linear relationship between age and regional CSFF in the cerebral WM (p < 0.001) and deep GM (p < 0.001). In addition, there was a statistically significant negative linear association between IEWF and age in the cerebral WM (p = 0.017) and cortex (p < 0.001). In the univariate correlation analysis, the normalized lateral ventricle volume correlated with the regional CSFF measurement in the cerebral WM (ρ = 0.64, p < 0.001), cortex (ρ = 0.62, p < 0.001), and deep GM (ρ = 0.66, p < 0.001). Our cross-sectional data demonstrate that brain tissue water in different compartments shows complex age-dependent patterns. Parenchymal CSFF, a measure of subvoxel CSF-like water in the brain tissue, is quadratically associated with age in the cerebral cortex and linearly associated with age in the cerebral deep GM and WM.

1440. Meta-regression Analysis of Worldwide Herpes Zoster Incidence

BackgroundMany studies have been conducted worldwide to estimate Herpes Zoster (HZ) incidence rates and temporal trends. We systematically reviewed and synthesized studies of HZ incidence rates in the general population using meta-analysis models. MethodsA random-effects meta-analysis was conducted to estimate HZ incidence from a published worldwide systematic literature review (SLR) including only individuals aged 50 years and older. Meta-regression was used to explore if variability in incidence rates could be explained by a combination of study-specific characteristics in the base model: age, gender, continent and year of data collection. The impact of adding additional covariates: case detection, case definition, study design, incidence type, patient type and latitude to the base model was also assessed. Results65 out of 69 studies from the SLR, were included in the analysis: 27 from Europe, 20 from North America, 11 from Asia and 7 from Oceania. There was much variability in study methodology and outcomes. Heterogeneity of incidence rates was greatest across studies conducted in Asia. Meta-analysis results showed that: incidence increased with age; was lower in males compared to females; was lower in Europe and North America compared to Asia and Oceania; and increased from the period prior to 2003 to the period after 2003. The final meta-regression model included continent, year of data collection, gender, age, cubic and quadratic terms for age, as well as an age x gender interaction term. The age x gender interaction suggests that the difference in incidence between males and females is greater in younger ages (e.g. 50-59), whereas in older age groups (e.g. 80+) incidence rates are similar between males and females. None of the additional covariates contributed significantly to the model. It was estimated that 15.5 million HZ cases occurred in 2020 worldwide in individuals aged 50 years and older, which in the absence of vaccination, is projected to increase to 19.8 million by 2030. ConclusionThe model allows for trends in incidence data to be explored based on influential covariates. Incidence rates were shown to vary by age, gender, continent, and over time.FundingGlaxoSmithKline Biologicals SA Disclosures Barbara P. Yawn, MD, Msc, ORCID: 0000-0001-7278-5810, The GSK group of companies (Advisor or Review Panel member, Research Grant or Support) Andrea Callegaro, PhD, GSK group of companies (Employee, Shareholder) Kyle Fahrbach, PhD, Evidera (Employee)The GSK group of companies (Other Financial or Material Support, - KF is employed by Evidera that received financial support by the GSK group of companies during the conduct of the study) Binod Neupane, PhD, Evidera (Employee)The GSK group of companies (Other Financial or Material Support, - BN is employed by Evidera that received financial support by the GSK group of companies during the conduct of the study) Hilde Vroling, MSc, The GSK group of companies (Research Grant or Support) Desiree Van Oorschot, Msc, The GSK group of companies (Employee, Shareholder) Desmond Curran, PhD, The GSK group of companies (Employee, Shareholder)

Transmetatarsal Amputation Outcomes When Utilized to Address Foot Gangrene and Infection: A Retrospective Chart Review

A transmetatarsal amputation (TMA) is a widely utilized procedure to address foot gangrene and infection. Although a common procedure, so too are the associated complications. The purpose of this review was to evaluate TMA healing and to explore if there were associated variables correlating with healed vs. failed to heal TMA sites. To do so, the Medical Department Orthopaedics Division Electronic Database, West Virginia University, College of Medicine was retrospectively searched to identify all cases of TMAs (CPT code 28805) during the period of January 2011 through June 2019, and those variables that might impact TMA healing. Then both univariate and multivariable logistic regression analyses were performed to investigate the associations between these variables and TMA healing, and sensitivity analyses were also conducted to determine if the results resisted the influence of one unmeasured confounder. There were 39 patients (41 procedures) who would undergo a TMA. The mean average patient age was 53 (range 29-73) years old. The median postoperative follow-up period was 617 (range 199-3632) days. TMA mortality data revealed 0 deaths at 30 days, 2 (5.1%) at 1 year, 8 (20.5%) at 5 years. In our study, 29 (70.7%) of the TMAs would achieve primary healing at a median of 31 (range 16-253) days. When comparing the TMA healed group to the failed to heal group the following independent variables were considered: diabetes mellitus, HgA1c >8%, neuropathy, peripheral arterial disease, chronic kidney disease, active smoking status, previous surgery, and a clean margin metatarsal bone pathology specimen positive for osteomyelitis. Of the aforementioned, only neuropathy (odds ratio [OR] = 0.056, 95% confidence interval [CI] = 0-0.501, p = .0062) and positive bone margin (OR = 0.144, 95% CI = 0.022-0.835, p = .0385) were found to be significant in univariate logistic regression analysis. In multivariable logistic regression analyses where the potential confounders age, gender, and body mass index were accounted for, of the 8 independent variables of interest, only neuropathy (OR = 0.037, 95% CI = 0-0.497, p = .0036) remained significantly associated with the healing status. Neuropathy was present in 17 (58.6%) of the healed TMAs and in 12 (100%) of the failed to heal TMAs. However, the positive bone margin failed to reach statistical significance (OR = 0.079, 95% CI = 0-1.39, p = .1331). Results from another multivariable logistic regression model where a quadratic term for age was added revealed that positive bone specimen correlated with the TMA healing status with significance (OR = 0.051, 95% CI = 0.001- 0.560, p = .0404). A positive clean margin bone specimen was found in 3 (10.3%) of the healed TMAs and in 4 (44.4%) of the failed to heal TMAs. The sensitivity analysis where current ulceration was used as an unmeasured confounder indicated that the results regarding the association between neuropathy or positive bone margin and TMA healing, though inconclusive, resisted the influence of this unmeasured confounder. Hopefully these findings will be a beneficial addition to the current TMA literature and as such, further assist with informed surgical decision making.

66 A genome-wide association study for gestation length in swine

Abstract The objective of the current study was to conduct a genome-wide association on gestation length (GL) in different parities in swine. Sows (n = 831) belonging to the University of Nebraska – Lincoln resource population (Landrace X Nebraska Index Line) were utilized. GL was defined as the number of days between the final insemination and farrowing. Four traits, GL at parity 1, 2, 3 and 4 (GL1, GL2, GL3 and GL4, respectively) were investigated. Animals which were induced 24h prior to a farrowing event were removed from the analysis. Sows were genotyped with the Illumina SNP60 BeadArray. A Bayes C model with π=0.995 was implemented with fixed effects of contemporary group, development pen, diet, linear and quadratic terms for age at puberty (GL1; P &lt; 0.01), and linear and quadratic terms for farrowing age (GL2; P &lt; 0.01). Results are posterior means of 55,000 samples.Single marker association analysis (SMA) was performed in R utilizing a linear model on SNP from 1-Mb windows (n = 10) which explained the largest proportion of genetic variation in GL1. Top 10 (0.5% of all windows) 1-Mb windows accounted for a limited proportion of genetic variance, 7.75, 4.66, 3.45 and 2.05% in GL1, GL2, GL3 and GL4, respectively. Posterior mean heritability estimates (posterior SD) for GL1, GL2, GL3 and GL4 were 0.33 (0.06), 0.34 (0.07), 0.32 (0.08) and 0.20 (0.08), respectively. The top SNP (ASGA0017859, SSC4, 7.8 Mb) located in one of the two top common genomic regions associated with GL1, GL2 and GL3 displayed a difference of 1.1d in GL1 between alternate homozygotes (P &lt; 0.01). The top SNP from nine of the ten regions were significant (P &lt; 0.05) in the SMA. Two of these regions were in common with GL2 and GL3 where SNP with potential functional effects were found in ZFAT, MAML2 and CCDC82. Results suggest GL is a largely polygenic trait.

Age-related deficits in intracortical myelination in young adults with bipolar disorder type I

Previous studies have implicated white-matter-related changes in the pathophysiology of bipolar disorder. However, most of what is known is derived from in vivo subcortical white-matter imaging or postmortem studies. In this study, we investigated whole-brain intracortical myelin (ICM) content in people with bipolar disorder type I and controls. Between Sept. 1, 2014, and Jan. 31, 2017, we used a 3 T General Electric scanner to collect T1-weighted images in 45 people with bipolar disorder type I and 60 controls aged 17 to 45 years using an optimized sequence that was sensitive to ICM content. We analyzed images using a surfacebased approach. We used general linear models with quadratic age terms to examine the signal trajectory of ICM across the age range. In healthy controls, the T1-weighted signal followed an inverted-U trajectory over age; in people with bipolar disorder type I, the association between ICM and age followed a flat trajectory (p < 0.05, Bonferroni corrected). Exploratory analyses showed that ICM signal intensity was associated with duration of illness, age of onset, and anticonvulsant and antipsychotic use in people with bipolar disorder type I (p < 0.05, uncorrected). Because of the cross-sectional nature of the study, we were unable to comment on whether the effects were due to dysmyelination or demyelination in bipolar disorder. This foundational study is, to our knowledge, the first to show global age-related deficits in ICM maturation throughout the cortex in bipolar disorder. Considering the impact of myelination on the maintenance of neural synchrony and the integrity of neural connections, this work may help us better understand the cognitive and behavioural deficits seen in bipolar disorder.

Age at menopause and lifetime cognition: Findings from a British birth cohort study.

ObjectiveWe investigated whether cognitive performance between ages 43 and 69 years was associated with timing of menopause, controlling for hormone replacement therapy, childhood cognitive ability, and sociobehavioral factors.MethodsWe used data from 1,315 women participating in the Medical Research Council National Survey of Health and Development (a British birth cohort study) with known age at period cessation and up to 4 assessments of verbal memory (word-learning task) and processing speed (letter-cancellation task) at ages 43, 53, 60–64, and 69. We fitted multilevel models with linear and quadratic age terms, stratified by natural or surgical menopause, and adjusted for hormone replacement therapy, body mass index, smoking, occupational class, education, and childhood cognitive ability.ResultsVerbal memory increased with later age at natural menopause (0.17 words per year, 95% confidence interval [CI]: 0.07–0.27, p = 0.001); an association remained, albeit attenuated, after full adjustment (0.09, 95% CI: 0.02–0.17, p = 0.013). Verbal memory also increased with later age at surgical menopause (0.16, 95% CI: 0.06–0.27, p = 0.002), but this association was fully attenuated after adjustment. Search speed was not associated with age at menopause.ConclusionOur findings suggest lifelong hormonal processes, not just short-term fluctuations during the menopause transition, may be associated with verbal memory, consistent with evidence from a variety of neurobiological studies; mechanisms are likely to involve estrogen receptor β function. Further follow-up is required to assess fully the clinical significance of these associations.

Depressive Symptoms and Tau Accumulation in the Inferior Temporal Lobe and Entorhinal Cortex in Cognitively Normal Older Adults: A Pilot Study.

Depressive symptoms are common in older adults and associated with increased morbidity and cognitive decline. These symptoms occur during preclinical and prodromal stages of Alzheimer's disease (AD), but their relationship to tau, one of the main AD proteinopathies, is poorly understood. The objective of this study was to investigate the cross-sectional association between depressive symptoms and cerebral tau [18F T807 (also known as 18F-AV-1451) tau positron emission tomography (PET) imaging] in cognitively normal (CN) older adults. We measured depressive symptoms using the Geriatric Depression Scale (GDS), and in vivo cerebral tau using T807 PET in 111 CN older adults. We employed general linear regression models to evaluate the relationship of GDS score regressed on entorhinal cortex (EC) or inferior temporal (IT) tau in separate backward elimination models. Other predictors included age, sex, and in secondary analyses, amyloid (Pittsburgh Compound B PET). Higher GDS was significantly associated with greater IT tau (partial r = 0.188, p = 0.050) and marginally associated with greater EC tau (partial r = 0.183, p = 0.055). In additional analyses including both linear and quadratic age terms, we found a significant U-shaped relation of GDS to age (p = 0.001). Results suggest that IT and EC tau are modestly associated with depressive symptoms in CN older adults. Findings suggest a link between depressive symptoms and tau-mediated neurodegeneration in a region vulnerable in AD. Future longitudinal studies examining the association of more severe depressive symptoms and cerebral tau accumulation are needed to substantiate this finding and to guide prevention and treatment in AD.

A unified approach for assessing heterogeneity in age–period–cohort model parameters using random effects

Age-period-cohort models are a popular tool for studying population-level rates; for example, trends in cancer incidence and mortality. Age-period-cohort models decompose observed trends into age effects that correlate with natural history, period effects that reveal factors impacting all ages simultaneously (e.g. innovations in screening), and birth cohort effects that reflect differential risk exposures that vary across birth years. Methodology for the analysis of multiple population strata (e.g. ethnicity, cancer registry) within the age-period-cohort framework has not been thoroughly investigated. Here, we outline a general model for characterizing differences in age-period-cohort model parameters for a potentially large number of strata. Our model incorporates stratum-specific random effects for the intercept, the longitudinal age trend, and the model-based estimate of annual percent change (net drift), thereby enabling a comprehensive analysis of heterogeneity. We also extend the standard model to include quadratic terms for age, period, and cohort, along with the corresponding random effects, which quantify possible stratum-specific departures from global curvature. We illustrate the utility of our model with an application to metastatic prostate cancer incidence (2004-2013) in non-Hispanic white and black men, using 17 population-based cancer registries in the Surveillance, Epidemiology, and End Results Program.

Longitudinal Study of the Emerging Functional Connectivity Asymmetry of Primary Language Regions during Infancy.

Cross-sectional studies of the language system in early infancy suggest that the basic neural mechanisms are in place even before birth. This study represents the first of its kind, using a large longitudinal sample of infants, to delineate the early language-related transition toward interhemispheric functional asymmetry in the brain using resting-state functional MRI. More generally, our findings suggest that increasing interhemispheric functional symmetry in the first year might be a general principle of the developing brain governing multiple functional systems, including those that will eventually become lateralized in adulthood. Although resting-state functional MRI cannot provide direct insights into the developmental mechanisms of language lateralization, this study reveals language-related functional connectivity changes during infancy, marking critical points in the development of the brain's functional architecture.

Reference Values For Standing Broad Jump In Colombian Schoolchildren

PURPOSE: Muscular power refers to the ability to perform high-intensity exercise for a fraction of a second to several minutes. Therefore, the purpose of this study was to develop age-and sex-specific normative reference values for lower-body muscular power assessed by the standing broad jump (SBJ) in Colombian schoolchildren. METHODS: A total of 7244 children and adolescents (55.7% girls, with a sample age range of 9-17.9 years) completed the SBJ test (median age, in years = 12.8 (SD 2.3); 25th-75th percentile: 11.0-15.0. The distance between takeoff and the heel of the closest foot at landing was recorded in centimeters, and participants were allowed one more try if they landed with their hands behind their feet. Smoothed percentile curves and tables for the 3rd, 10th, 25th, 50th, 75th, 90th and 97th percentiles were calculated using Cole’s LMS method. RESULTS: The one-way ANOVA tests showed that maximum SBJ (cm) was higher in boys than in girls (p<0.01). Post hoc analyses within sexes showed yearly increases in SBJ scores in all ages. In boys, the maximum SBJ scores 50th percentile ranged from 110 to 165 cm. In girls, the 50th percentile ranged from SBJ scores was 96 to 120. Both linear and quadratic age terms were statistically significant predictors of SBJ trends across age. CONCLUSIONS: Our results provide reference standards for sex- and age-specific SBJ scores in Colombian schoolchildren aged 9-17.9 years for the first time. The proposed reference values can be used to interpret SBJ scores in Colombian schoolchildren. Funding COLCIENCIAS (Contract N° 671-2014 Code 122265743978).

Longitudinal development of match-running performance in elite male youth soccer players.

This study longitudinally examined age-related changes in the match-running performance of retained and released elite youth soccer players aged 8-18 years. The effect of playing position on age-related changes was also considered. Across three seasons, 263 elite youth soccer players were assessed in 1-29 competitive matches (988 player-matches). For each player-match, total distance and distances covered at age group-specific speed zones (low-speed, high-speed, sprinting) were calculated using 1 Hz or 5 Hz GPS. Mixed modeling predicted that match-running performance developed nonlinearly, with age-related changes best described with quadratic age terms. Modeling predicted that playing position significantly modified age-related changes (P < 0.05) and retained players covered significantly more low-speed distance compared with released players (P < 0.05), by 75 ± 71 m/h (mean ± 95% CI; effect size ± 95% CI: 0.35 ± 0.34). Model intercepts randomly varied, indicating differences between players in match-running performance unexplained by age, playing position or status. These findings may assist experts in developing training programs specific to the match play demands of players of different ages and playing positions. Although retained players covered more low-speed distance than released players, further study of the actions comprising low-speed distance during match play is warranted to better understand factors differentiating retained and released players.

Establishing Normative Reference Values for Handgrip Among Hungarian Youth

Purpose: The purpose of this study was to examine age- and sex-related variation in handgrip strength and to determine reference values for the Hungarian population. Method: A sample of 1,086 Hungary youth (aged 11–18 years old; 654 boys and 432 girls) completed a handgrip strength assessment using a handheld dynamometer. Quantile regression was used to compute separate models for boys and girls and included a linear, cubic, and quadratic term for age to account for nonlinear patterns. These terms were tested for statistical significance using the Wald statistical test with p < .05. Age- and sex-specific centiles were generated and the 50th percentile was used to describe the overall patterns in handgrip strength. Results: The linear, cubic, and quadratic terms for age fitted the data well for boys (p < .05), while both linear and quadratic terms for age were statistically significant for girls (p < .05). The 50th percentile values resulted in 21.4 kg, 21.7 kg, 25.0 kg, 30.0 kg, 35.4 kg, 40.0 kg, 42.6 kg, and 42.0 kg for boys aged 11 to 18 years old, respectively. The same percentile resulted in 20.0 kg, 19.5 kg, 19.6 kg, 20.3 kg, 21.6 kg, 23.5 kg, 26.1 kg, and 29.2 kg for girls aged 11 to 18 years old, respectively. Conclusions: Muscle strength as determined by handgrip has distinct age-related patterns in boys and girls. We have accounted for biological age differences and developed norm-referenced values that can be used to interpret handgrip assessment scores obtained from school-aged children in Hungary.

Establishing Normative Reference Values for Standing Broad Jump Among Hungarian Youth

Purpose: The purpose of this study was to examine age and sex trends in anaerobic power assessed by a standing broad jump and to determine norm-referenced values for youth in Hungary. Method: A sample of 2,427 Hungarian youth (1,360 boys and 1,067 girls) completed the standing broad jump twice, and the highest distance score was recorded. Quantile regression was used to fit standing broad jump trends across linear and quadratic functions of age. Statistical significance was determined with bootstrap confidence intervals and the Wald test with p < .05. Age-by-sex specific centiles were generated and the 50th percentile was used to describe the overall patterns. Results: Standing broad jump scores increased steadily in boys from age 11 through 18 years with a discrete plateau at the end of adolescence. Girls' standing broad jump scores of those who performed above the median increased with age and plateaued later in the adolescence. Both linear and quadratic age terms were statistically significant predictors of standing broad jump trends across age (p < .05), but the relations varied depending on the percentile. The 50th percentile values resulted in 147.0 cm, 162.0 cm, 175.0 cm, 186.0 cm, 195.0 cm, 202.0 cm, 207.0 cm, and 210.0 cm for boys aged 11 to 18 years old, respectively, and 140.0 cm, 143.9 cm, 147.3 cm, 150.0 cm, 152.1 cm, 153.7 cm, 154.6 cm, and 155.0 cm for girls aged 11 to 18 years old, respectively. Conclusions: This study provides normative reference charts that take into account age and sex differences in standing broad jump performance. The proposed reference values can be used to interpret standing broad jump scores in Hungarian youth.

The effect of age, diagnosis, and their interaction on vertex-based measures of cortical thickness and surface area in autism spectrum disorder.

Autism spectrum disorder (ASD) is a lifelong neurodevelopmental condition that is accompanied by an atypical development of brain maturation. So far, brain development has mainly been studied during early childhood in ASD, and using measures of total or lobular brain volume. However, cortical volumetric measures are a product of two distinct biological neuroanatomical features, cortical thickness, and surface area, which most likely also have different neurodevelopmental trajectories in ASD. Here, we therefore examined age-related differences in cortical thickness and surface area in a cross-sectional sample of 77 male individuals with ASD ranging from 7 to 25 years of age, and 77 male neurotypical controls matched for age and FSIQ. Surface-based measures were analyzed using a general linear model (GLM) including linear, quadratic, and cubic age terms, as well as their interactions with the main effect of group. When controlling for the effects of age, individuals with ASD had spatially distributed reductions in cortical thickness relative to controls, particularly in fronto-temporal regions, and also showed significantly reduced surface area in the prefrontal cortex and the anterior temporal lobe. We also observed significant group × age interactions for both measures. However, while cortical thickness was best predicted by a quadratic age term, the neurodevelopmental trajectory for measures of surface area was mostly linear. Our findings suggest that ASD is accompanied by age-related and region-specific reductions in cortical thickness and surface area during childhood and early adulthood. Thus, differences in the neurodevelopmental trajectory of maturation for both measures need to be taken into account when interpreting between-group differences overall.

Age-related Changes in Mammographic Density and Breast Cancer Risk

High mammographic density is a strong breast cancer risk factor. Density normally declines with aging. We investigated whether the level of decline in mammographic density is related to breast cancer risk using a nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Prospect cohort. This cohort was recruited among participants of a population-based breast cancer screening program in the Netherlands between 1993 and 1997. We examined whether age-related changes in mammographic density were different for 533 cases and 1,367 controls who were 49-69 years of age at the time of recruitment into the cohort. We used mixed models with linear and quadratic terms for age and interaction terms between age terms and case status. The percent mammographic density at the first available mammogram was higher for cases than for controls (25.2% vs. 22.5%) (P = 0.003). The average decline in density over 10 years was 11% in both cases and controls (P = 0.56). When studying changes among 4 categories of density, we saw some indication that large changes may influence breast cancer risk. Although no difference was seen in the average decline, we cannot exclude that large changes may influence breast cancer risk.

Gender and socioeconomic disparities in BMI trajectories in the Seychelles: a cohort analysis based on serial population-based surveys

BackgroundThe relationship between body mass index (BMI) and socioeconomic status (SES) tends to change over time and across populations. In this study, we examined, separately in men and women, whether the association between BMI and SES changed over successive birth cohorts in the Seychelles (Indian Ocean, African region).MethodsWe used data from all participants in three surveys conducted in 1989, 1994 and 2004 in independent random samples of the population aged 25-64 years in the Seychelles (N = 3'403). We used linear regression to model mean BMI according to age, cohort, SES and smoking status, allowing for a quadratic term for age to account for a curvilinear relation between BMI and age and interactions between SES and age and between SES and cohorts to test whether the relation between SES and BMI changed across subsequent cohorts. All analyses were performed separately in men and women.ResultsBMI increased with age in all birth cohorts. BMI was lower in men of low SES than high SES but was higher in women of low SES than high SES. In all SES categories, BMI increased over successive cohorts (1.24 kg/m2 in men and 1.51 kg/m2 for a 10-year increase in birth cohorts, p < 0.001). The difference in BMI between men or women of high vs. low SES did not change significantly across successive cohorts (the interaction between SES and year of birth of cohort was statistically not significant). Smoking was associated with lower BMI in men and women (respectively -1.55 kg/m2 and 2.46 kg/m2, p < 0.001).ConclusionsAlthough large differences exist between men and women, social patterning of BMI did not change significantly over successive cohorts in this population of a middle-income country in the African region.

Short communication: Interaction of energy balance, feed efficiency, early lactation health events, and fertility in first-lactation Holstein, Jersey, and reciprocal F1 crossbred cows

First-lactation Holstein (HH), Jersey (JJ), and crossbred cows (HJ and JH, with sire breed listed first, followed by dam breed) were observed for cumulative energy intake (CEI15) and energy used for milk production (CEL15) at wk 15 of lactation in addition to recordings of health problems and pregnancy. Cumulative energy balance (CEB15) was calculated from CEI15 and estimates of expenditures at wk 15 of lactation. Feed efficiency (FE15) was calculated by dividing CEL15 by CEI15. Data included 140 cows with 43, 34, 41, and 22 in the HH, HJ, JH, and JJ groups, respectively. The first incidence of displaced abomasum (DA), ketosis (KET), mastitis (MAST), and metritis (MET) was recorded in the first 100 d of lactation with an incidence of the disease coded as 1 and no incidence coded as 0. Pregnancy (PREG) at d 150 was recorded as 1 if a cow had conceived by d 150 and 0 if she had not. Logistic regression was used to analyze health and fertility with fixed effects in the model including genetic group, linear and quadratic effects for age at calving, and year-season of freshening group. Pregnancy was analyzed with the same variables and the addition of CEB15. In other analyses, CEB15, CEI15, CEL15, and FE15 were response variables with the same explanatory variables plus health events (MAST, DA, MET, and KET), where each health event was a separate analysis. Genetic group effects were significant in the occurrence of MAST and a trend for MET, but were not significant for PREG, DA, and KET. Significant odds ratio for MAST was 19.6 for HJ cows when compared with that for HH cows. Thus, HJ cows were 19.6 times more likely than HH cows to have an incidence of MAST. The trend was for HJ and JH to have a lower odds ratio of MET than that of HH. No other genetic group effects were significant in any of the disease and PREG models. The linear and quadratic terms for age at calving were not significant. An occurrence of MAST decreased FE15 by 5.2±2.2%. Mastitis also decreased CEI15 and CEL15, but the compensatory reductions left the CEB15 unaffected. An occurrence of a DA decreased CEI15 and an incidence of KET decreased CEB15.