Gymnastik- och idrottshögskolan, GIH

Background: Adolescence is a crucial phase for the development of cognitive abilities linked to academic performance. Factors such as physical activity (PA) and fitness have been hypothesized to be linked to these outcomes, although the evidence is inconclusive. This study aimed to examine the associations between PA, fitness, academic, and cognitive performance in the same sample of adolescents.

Methods: In this cross-sectional study, 1139 Swedish adolescents (mean age 13.4 years) participated. We assessed PA (accelerometry), cardiovascular fitness (submaximal ergometer test), cognitive performance (computer-based test assessing episodic and working memory with 3 tests per domain), and academic performance (grades in math and language, Swedish). We utilized multilevel mixed models to explore associations and structural equation modeling to perform mediation analyses.

Results: We found a weak positive association between cardiovascular fitness and math grades (b: 0.18, 95% CI: 0.09, 0.26 β: 0.18), language grades (b: 0.16, 95% CI: 0.07, 0.25 β: 0.13), and cognitive performance (b: 0.01, 95% CI: 0.00, 0.02 β: 0.11). Further, cognitive performance scores mediated 40% of the associations between fitness and math, and language grades. Adolescents with parents with short education (≤12 years of education) or foreign-born had lower fitness levels and grades in math and language (all p < 0.05).

Conclusion: Fitness was the only significant factor associated with cognitive and academic performance, although the association was weak. Given our findings of low fitness and academic performance among adolescents with parents with short education or parents born abroad, future studies should tailor their interventions to ensure the inclusion of these groups.

BACKGROUND Childhood maltreatment (CM) may increase cardiovascular disease (CVD) risk through behavioral and health pathways; while maintaining cardiovascular health, Life's Essential 8 (LE8) may modify this association. OBJECTIVES The objective of the study was to examine the link between CM and LE8, and to quantify the potential moderating role of LE8 scores in CM-related CVD risk for men and women. METHODS We included 153,399 participants aged >= 40 years at baseline in the U.K. Biobank. CM was assessed using the online Childhood Trauma Screener. LE8 scores were calculated based on 8 behavioral and health factors. Incident CVDs were identified through linkage to patient and death registers up to 2022. Linear and Cox regressions were used. RESULTS All CM events were significantly associated with lower LE8 scores in both sexes, with stronger associations observed with increasing cumulative CM exposure (beta 1CM =-0.58, 95% CI:-0.72 to-0.44; beta 2CM =-1.17, 95% CI:-1.36 to-0.97; beta >= 3CM =-2.26, 95% CI:-2.47 to-2.05). Compared to individuals with no CM exposure and low LE8 scores, those maintaining moderate-to-high LE8 scores demonstrated a substantial reduction in risk for all CVD events, regardless of the number of CM events experienced. However, among participants with low total LE8 scores, women appeared more vulnerable than men to myocardial infarction when exposed to cumulative CM events. CONCLUSIONS The impact of early-life adversities can be offset by adopting good lifelong lifestyle practices. This study underscores the need to identify individuals, particularly women, with experiences of cumulative CM events and support interventions to improve their opportunity, capability, and motivation to enhance LE8. (JACC Adv. 2026;5:102483) (c) 2026 The Authors. Published by Elsevier on behalf of the American College of Cardiology Foundation. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Physical activity (PA) plays a key role in children's health, yet it remains unclear why girls are often less active and more sedentary than boys. This study examined genetic and environmental (shared and non-shared) influences on device-measured PA and sedentary time (SED) across girls and boys. This cross-sectional study contained data on zygosity, sex, PA, and SED for 2046 9-year-old twins in Sweden. The accelerometer-measured PA was expressed as the proportion of time in SED, light (LPA), moderate (MPA) or vigorous PA (VPA). Structural equation modelling within a twin framework estimated the heritability of PA and SED, decomposing variance into additive genetic (A), shared environment (C), and non-shared environment (E). Quantitative sex differences were examined by allowing the variance components (A, C, E) to differ across sexes. In the total cohort, genetic contribution was highest in VPA (Atotal: 0.64) but lower in SED, LPA and MPA (Atotal: 0.50-0.55). Boys and girls had differing patterns of genetic contributions, with the largest contributions among girls found for LPA (Agirl: 0.44; Aboy: 0.37) while the genetic contribution in VPA was larger in boys (Agirl: 0.15; Aboy: 0.57), and the difference was statistically significant for VPA (p = 0.001). While the non-shared environment was similar in all models, the shared environment showed the opposite pattern to the genetic contributions. This twin study shows that genetic influences on PA and SED differ by sex, highlighting the importance of considering how biological mechanisms that drive activity patterns might differ across sex, especially in vigorous physical activity.

INTRODUCTION: Cardiorespiratory fitness (CRF) is linked to dementia risk, but moderating factors remain unclear. This study examined how and when CRF in adulthood is associated with late-onset dementia (> 65 years) and whether sex, civil status, or education moderate this association.

METHODS: In a cohort of 370,980 dementia-free individuals followed for a mean of 11.9 (standard deviation 6.0) years, CRF was estimated via a submaximal cycle test, with dementia incidence obtained from Swedish National Healthcare Registries.

RESULTS: Results showed that high CRF was associated with lower dementia risk in those under age 55 (hazard ratio [HR]: 0.58, 95% confidence interval [CI] 0.36-0.92) and those > 55 (HR: 0.75, 95% CI 0.63-0.89) at CRF assessment. Medium education levels moderate the association in individuals < 55 years.

DISCUSSION: These findings underscore the role of maintaining a high CRF in dementia prevention, emphasizing education level as a critical moderating factor.

HIGHLIGHTS: High cardiorespiratory fitness (CRF) is longitudinally associated with a lower risk of late-onset dementia.The association was evident in those both under and over age 55 at CRF assessment.Higher education levels moderated the relationship in those < 55 years.Sex and civil status did not moderate the association.

INTRODUCTION: The relationship between sleep, other dementia risk factors, and dementia remains unclear. We aim to explore these associations using a two-sample Mendelian randomization (MR) approach.

METHODS: We identified genetic instrumental variables for sleep characteristics from the UK Biobank and obtained summary-level genetic association data for dementia outcomes, including Alzheimer's disease (AD), from the FinnGen consortium. We applied inverse-variance weighted (IVW) MR to examine the associations between sleep characteristics and dementia outcomes. Multivariable MR was subsequently employed to assess the influence of additional dementia-relevant factors on these relationships.

RESULTS: = 3.02, 95% confidence interval [CI]: 1.28-7.10, p = 0.01). Yet this association was largely attenuated after adjusting for education and low-density lipoprotein (LDL).

DISCUSSION: These findings indicate that the association between insomnia and AD is complex and indirect, potentially operating through social-behavioral factors (education) and biological pathways such as LDL cholesterol.

PURPOSE: The transition phase between childhood and adolescence is critical, given the observation of increased mental health issues during this period, coupled with the absence of efficient intervention tools. This study aims to examine a possible effect of physical activity on mental health symptoms in adolescents during this transitional age.

METHODS: We used data from a large-scale population-based Swedish twin sample of 14,083 individuals to investigate cross-sectional and longitudinal associations between physical activity and mental health problems during childhood and adolescence. We examine different aspects of mental health symptoms, including internalizing and externalizing symptoms. We applied generalized estimating equations to investigate the associations and explored potential familial confounding using within-twin pair analysis.

RESULTS: We found high physical activity intensity and frequency to be associated with better mental health throughout childhood and adolescence, cross-sectionally and longitudinally. Compared to those who reported low, those reporting high physical activity intensity and frequency in both childhood and/or adolescence had significantly lower symptoms of mental health at age 15. This association was statistically significant for both internalizing and externalizing symptoms. The within-twin pair analysis showed that familial confounding factors can largely explain the association with the externalizing scale, but not the internalizing scale.

DISCUSSION: Physical activity in childhood and adolescence may play an essential role in reducing the risk of developing mental health problems, especially internalizing symptoms. Implementing acceptable, low-risk, and cost-effective interventions to promote physical activity could effectively safeguard young individuals from these symptoms.

BACKGROUND AND OBJECTIVES: Individuals aged 70 and older frequently experience an increased risk of deficits in both physical and cognitive functions. However, the natural progression and interrelationship of these deficits, as well as their neurologic correlates, remain unclear. We aimed to classify the data-driven physical-cognitive phenotypes and then investigate their associations with neuroimaging markers.

METHODS: This cross-sectional study included 70-year-old participants from the Gothenburg H70 Birth Cohort (2014-2016). Based on physical performance (grip strength, balance, walking speed, and chair stand) and cognitive measures (episodic memory, perceptual speed, executive function, verbal fluency, and visuospatial abilities), we applied latent class analysis to identify physical-cognitive phenotypes. Based on the brain MRI measurements, 3 groups of neuroimaging markers were involved-neurodegeneration, cerebral small vessel disease (cSVD), and microstructural white matter (WM) integrity. We performed multinomial logistic regressions to examine the differences between the physical-cognitive phenotypes.

RESULTS: In total, 1,140 participants (female: 53.3%) without dementia and disability were included in the study, with 721 (female: 52.2%) undergoing MRI scans. Three physical-cognitive phenotypes were identified: an "optimal" group characterized by high performance in both physical and cognitive functions, an "intermediate" group showing a slight reduction in both domains, and a "physical deficit" group marked by a significant reduction in physical performance. Compared with the optimal group, the other 2 groups were more likely to present with vascular risk factors. The physical deficit group had higher odds of experiencing depression compared with the intermediate group (adjusted odds ratio [aOR] 2.9, 95% CI 1.4-5.9). Compared with the optimal group, the odds of presenting all 3 severe neuroimaging markers were higher in both the intermediate (aOR 3.4, 95% CI 1.5-7.9) and physical deficit (aOR 10.3, 95% CI 2.4-45.0) groups.

DISCUSSION: This study highlights the variability in physical and cognitive performance among older adults and suggests that neuroimaging markers of neurodegeneration, cSVD, and microstructural WM integrity may account for these variations. Our findings indicate the potential for developing group-based strategies to prevent and manage age-related functional decline. Further research with larger sample sizes is needed to deepen our understanding of physical-cognitive decline patterns.

Background

How the environment in which physical activity takes place influences brain health remains insufficiently studied. We aimed to investigate the association between outdoor physical activity and dementia in older adults, and to examine whether residential green space (GS) modifies this association.

Methods

This prospective longitudinal study used UK Biobank data from 187,724 adults aged 60-73 years at baseline (2006-2010) and 36,854 with brain Magnetic Resonance Imaging (2014-2021). Outdoor activity (via Metabolic Equivalent of Task) and GS (within 300 m of homes) were assessed, with dementia incidence tracked through electronic records until December 2022. Neuroimaging markers included hippocampal and total gray-matter volumes, and white-matter hyperintensity volume. Cox proportional hazards and linear regression models were applied.

Results

During a mean follow-up of 13.01 years, 7218 participants (47.1% female) developed dementia. After adjusting for covariates, higher outdoor activity is associated with a lower risk of all-cause dementia (HRtop vs bottom quartile = 0.84, 95% Confidence Interval [CI] 0.78-0.90). This association is most pronounced for vascular dementia (HR:0.72, 95%CI 0.63-0.83) and is stronger among those living in areas with high, compared to low, residential GS (0.73, 95%CI 0.63-0.85 vs 0.86, 95%CI 0.79-0.93, pinteraction = 0.04). Higher outdoor activity is also associated with higher hippocampal and total gray-matter volumes and fewer white-matter hyperintensities. A combined effect of outdoor activity and GS on hippocampal volume is observed.

Conclusions

Outdoor activity is linked to lower dementia risk, particularly in those living in more accessible GS. These findings underscore the importance of urban planning that prioritizes accessible GS to promote brain health in the aging population.

Background

Observational studies have provided inconsistent association between sleep characteristics and dementia, and the causal nature of this relationship remains unclear. This study aimed to investigate the comprehensive relationship between sleep characteristics and dementia using a bidirectional and multivariate Mendelian randomization (MR).

Method

Summarized single nucleotide polymorphism (SNP) data involved in this study was from genome‐wide association studies, including risk genes of multiple sleep characteristics (i.e., daytime napping, daytime sleepiness, sleep duration, insomnia, and being a morning person) and all‐cause and cause‐specific dementia (e.g., Alzheimer's disease [AD], Lewy body dementia, and vascular dementia [VaD]). Independent genetic variants associated with sleep characteristics and dementia were used as instrumental variables. Inverse‐variance weighted (IVW) test, supplemented by MR‐Egger and weighted median estimators, was used as the main analyses. Multivariate MR employed the multivariate IVW test to adjust for potential confounders, including education, body mass index, smoking, alcohol consumption, hypertension, low‐density lipoprotein (LDL) cholesterol, hearing loss, physical activity, depression, traumatic brain injury, and diabetes.

Result

When genetic variates of sleep characteristics were introduced as instrumental variables, a significant causal relationship between insomnia and AD (ORIVW = 3.02, 95% CI: 1.28—7.10, p = 0.01) was observed in the univariate MR. But this relationship was largely diluted after adjusting for education or LDL cholesterol in the Multivariate MR. When genetic variants of dementia were treated as instrumental variables in IVW analyses, all cause dementia was associated with the characteristic of being a morning person, with significant ORs ranging from 1.003 to 1.005 (p < 0.05). Instrumental variables of VaD and Lewy body dementia were associated with shorter sleep durations (p < 0.05).

Conclusion

The effect of insomnia on AD may largely modulated by education level and mediated by LDL cholesterol level. Future investigations are required to further verify the reversed relationship from dementia to other sleep characteristics, e.g., a shorter duration.

Introduction. Executive functions (EF) is essential for cognitive aging and vascular cognitive impairment. Habitual physical activity (PA) has been shown to yield positive effects on EF in aging. In this study, we aim (1) to investigate the relationship between EF and time spent in sedentary behaviour (SED), light-PA (LIPA), moderate-PA (MPA), and vigorous-PA (VPA), respectively; and (2) to examine the potential beneficial effect of combined movement behaviours.

Methods. The study consisted of 4592 participants (women: 52.6%), aged 50 to 65 years, from the Swedish CArdioPulmonary bioImage Study(SCAPIS) in Gothenburg region (data collection: 2013-2017). The Trail Making Tests (A and B) were applied to evaluate the EF. ActiGraph accelerometer was employed to evaluate the daily movement patterns objectively. After adjusting for covariates in demographic factors, cardiorespiratory fitness, and vascular risk factors, piecewise linear and linear regression models were used to examine the relationship between movement patterns and EF.

Results. In the fully adjusted model, when daily sedentary time was less than 10 hours, an increased SED time was positively associated with EF score. However, a negative association was observed between SED time and EF score when daily sedentary time exceeded 10 hours. When daily LIPA time exceeded 4 hours, LIPA time was found to have a negative association with EF score. An increase in MPA time was positively associated with EF score when daily MPA was less than 45 minutes. A significant positive association was observed between conducting daily VPA within 20 minutes and EF score. The majority of participants in our study demonstrated a movement pattern characterized by high levels of cardiorespiratory fitness, sedentary time within 10 hours, LPA more than 4 hours, MPA more than 45 minutes, and VPA more than 20 minutes. This particular movement pattern was significantly and positively associated with EF scores compared to other groups.

Discussion. The association between EF and specific movement behaviours varied depending on their daily duration. In this study, the majority of middle-aged and older adults demonstrated an active movement pattern, which was positively associated with EF. Further research is needed to investigate the underlying pathways that explain this