The longitudinal association between objectively measured physical activity and mental health among Norwegian adolescents

Background: Mental health among young people in many countries, including Norway, seems to be deteriorating. Physical activity (PA) has been positively associated with mental health. However, methodological issues related to study design and measurement of PA and mental health outcomes currently limits our understanding of the relationship. The purpose of the present study is to explore the prospective relationship between objectively measured PA and mental health outcomes. More specifically, volume (total PA), intensity (moderate-to-vigorous PA [MVPA]) and sedentary behaviour (SED) were explored in relation to mental health problems (MHP) and mental wellbeing (MWB). Methods: Data from 599 adolescents (54.4% female, mean age at baseline ±SD 13.3 ± 0.3 years) were collected annually during their 3 years (T1, T2 and T3) at lower secondary school. PA was measured using accelerometry. MWB was measured using the ‘Warwick-Edinburgh Mental Wellbeing Scale’ and MHP by the ‘Strengths and Difficulties Questionnaire’. Multiple linear regression was performed to explore relationships between changes in PA/SED (between T1-T3) and MWB/MHP (at T3). The term ‘movement categories’ was used to refer to components on the movement continuum and includes volume (total PA), intensity (MVPA) and SED. Results: Among boys, any increase in SED was positively associated with MWB (β = 0.05, 95% CI: 0.01 to 0.10), whereas a small positive association between an increase in total PA (volume) and MWB was found among girls (β = 1.13, 95% CI: 0.05 to 2.21). There were no associations between changes in any movement categories [total PA (volume), MVPA, SED] and score on MHP at T3, neither for girls nor boys. Conclusion: This study provided no clear evidence of any association between change in volume or intensity of PA and MHP among an overall healthy adolescent study sample. There was, however, evidence of a relationship between increased SED and MWB among boys and increased volume of PA and MWB among girls. The relationship between movement categories and mental health may depend on the measurement used to assess both PA/SED and variables of mental health. Future research would be strengthened by researchers clarifying what construct of mental health is being used and measured.publishedVersio

Impact of White Matter Lesions on Cognition in Stroke Patients Free from Pre-Stroke Cognitive Impairment: A One-Year Follow-Up Study

Background/Aim: Post-stroke cognitive impairment and dementia may be caused by pure vascular, pure degenerative or mixed disease. The relation between post-stroke cognitive impairment and the combination of vascular pathology and degenerative changes is less evaluated. We aimed to evaluate the associations between white matter lesions (WMLs) and patient performance 1 year after stroke on tests of executive functioning, memory and visuospatial function, adjusted for the effects of lifestyle and disease-related factors, including medial temporal lobe atrophy (MTLA). Methods: Patients with a first-ever stroke or transient ischemic attack were invited to participate in the study. The associations between the cognitive test performances and WMLs were studied using linear regression [Trail Making Test B (TMT B) and 10-word test] and logistic regression (Clock Drawing Test). Results: In total, 199 patients completed the follow-up. The TMT B (p = 0.029) and the 10-word test (p = 0.014) were significantly associated with WMLs; however, the Clock Drawing Test (p = 0.19) was not. The TMT B (p = 0.018) and the 10-word test (p ≤ 0.001) were both significantly associated with MTLA. Conclusion: Impaired executive functioning and memory are significantly associated with WMLs and MTLA. The mechanisms explaining post-stroke cognitive impairment are multifactorial, including different types of vascular pathology and coexisting vascular and degenerative changes

Aerobic fitness mediates the intervention effects of a school-based physical activity intervention on academic performance. The school in Motion study - A cluster randomized controlled trial.

Little information exists on the mechanism of how physical activity interventions effects academic performance. We examined whether the effects of a school-based physical activity intervention on academic performance were mediated by aerobic fitness. The School in Motion study was a nine-month cluster randomized controlled trial between September 2017 and June 2018. Students from 30 Norwegian lower secondary schools (N = 2,084, mean age [SD] = 14 [0.3] years) were randomly assigned into three groups: the Physically Active Learning (PAL) intervention (n = 10), the Don't Worry-Be Happy (DWBH) intervention (n = 10), or control (n = 10). Aerobic fitness was assessed by the Andersen test and academic performance by national tests in reading and numeracy. Mediation was assessed according to the causal steps approach using linear mixed models. In the PAL intervention, aerobic fitness partially mediated the intervention effect on numeracy by 28% from a total effect of 1.73 points (95% CI: 1.13 to 2.33) to a natural direct effect of 1.24 points (95% CI: 0.58 to 1.91), and fully mediated the intervention effect on reading, with the total effect of 0.89 points (95% CI: 0.15 to 1.62) reduced to the natural direct effect of 0.40 points (95% CI: -0.48 to 1.28). Aerobic fitness did not mediate the effects on academic performance in the DWBH intervention. As aerobic fitness mediated the intervention effect on academic performance in one intervention, physical activity of an intensity that increases aerobic fitness is one strategy to improve academic performance among adolescents.Medical Research Council (grant number MC_UU_00006/5)

Device-measured physical activity, adiposity and mortality: a harmonised meta-analysis of eight prospective cohort studies

Background: The joint associations of total and intensity-specific physical activity with obesity in relation to all-cause mortality risk are unclear. Methods: We included 34 492 adults (72% women, median age 62.1 years, 2034 deaths during follow-up) in a harmonised meta-analysis of eight population-based prospective cohort studies with mean follow-up ranging from 6.0 to 14.5 years. Standard body mass index categories were cross-classified with sample tertiles of device-measured total, light-to-vigorous and moderate-to-vigorous physical activity and sedentary time. In five cohorts with waist circumference available, high and low waist circumference was combined with tertiles of moderate-to-vigorous physical activity. Results: There was an inverse dose–response relationship between higher levels of total and intensity-specific physical activity and mortality risk in those who were normal weight and overweight. In individuals with obesity, the inverse dose–response relationship was only observed for total physical activity. Similarly, lower levels of sedentary time were associated with lower mortality risk in normal weight and overweight individuals but there was no association between sedentary time and risk of mortality in those who were obese. Compared with the obese-low total physical activity reference, the HRs were 0.59 (95% CI 0.44 to 0.79) for normal weight-high total activity and 0.67 (95% CI 0.48 to 0.94) for obese-high total activity. In contrast, normal weight-low total physical activity was associated with a higher risk of mortality compared with the obese-low total physical activity reference (1.28; 95% CI 0.99 to 1.67). Conclusions: Higher levels of physical activity were associated with lower risk of mortality irrespective of weight status. Compared with obesity-low physical activity, there was no survival benefit of being normal weight if physical activity levels were low.publishedVersio

Outcome based subgroup analysis: a neglected concern

A subgroup of clinical trial subjects identified by baseline characteristics is a proper subgroup while a subgroup determined by post randomization events or measures is an improper subgroup. Both types of subgroups are often analyzed in clinical trial papers. Yet, the extensive scrutiny of subgroup analyses has almost exclusively attended to the former. The analysis of improper subgroups thereby not only flourishes in numerous disguised ways but also does so without a corresponding awareness of its pitfalls. Comparisons of the grade of angina in a heart disease trial, for example, usually include only the survivors. This paper highlights some of the distinct ways in which outcome based subgroup analysis occurs, describes the hazards associated with it, and proposes a simple alternative approach to counter its analytic bias. Data from six published trials show that outcome based subgroup analysis, like proper subgroup analysis, may be performed in a post-hoc fashion, overdone, selectively reported, and over interpreted. Six hypothetical trial scenarios illustrate the forms of hidden bias related to it. That bias can, however, be addressed by assigning clinically appropriate scores to the usually excluded subjects and performing an analysis that includes all the randomized subjects. A greater level of awareness about the practice and pitfalls of outcome based subgroup analysis is needed. When required, such an analysis should maintain the integrity of randomization. This issue needs greater practical and methodologic attention than has been accorded to it thus far

contingencytables: Statistical Analysis of Contingency Tables

<p>First stable release on CRAN. The assets below correspond to a snapshot of this GitHub repository at the time of release. It should contain the same files present on the <a href="https://cran.r-project.org/package=contingencytables">CRAN repo</a> plus some development files that do not interfere with how the package functions.</p> <p>The functions on this version of the package should work exactly like the ones shared on <a href="https://contingencytables.com/software-resources">https://contingencytables.com/software-resources</a>, except for eventual minor, backwards-compatible changes that were introduced to make the package publication-ready.</p> <p>Users should prefer to use the CRAN version of this package. The main purpose of this GitHub release is record-keeping.</p&gt

Gender differences in all-cause, cardiovascular and cancer mortality during long-term follow-up after acute myocardial infarction; a prospective cohort study

Background Gender differences in short-term mortality in acute myocardial infarction (AMI) have been studied extensively, whereas gender differences in long-term mortality and cause of death largely remain unknown. The aim of this study was to assess the long-term risk of all-cause, cardiovascular and cancer death after AMI in women compared to men. Methods Consecutive AMI patients were enrolled in a prospective registry between 2005 and 2011. Date and cause of death were obtained by linkage with the Norwegian Cause of Death Registry, with censoring date 31 December 2012. AMI patients with ST-segment elevation (STEMI, n = 5159) and without (NSTEMI, n = 4899) were analysed separately. Results The 5-years all-cause mortality rates in STEMI were 29% in women vs. 17% in men, and 42% vs. 29% in NSTEMI, respectively. After adjustment for age and other confounders, women with STEMI had similar (HR 1.13 [95% CI: 0.98–1.32]) and women with NSTEMI lower (HR 0.82 [95% CI: 0.73–0.92]) risk of long-term all-cause mortality compared to men. Competing-risks analysis showed no significant gender differences in age-adjusted risk of cardiovascular death nor of cancer death. In both genders, the annual risk of cardiovascular death was low after 1 year, but exceeded annual risk of cancer death throughout follow-up. Conclusion During long-term follow-up, women with STEMI had similar and women with NSTEMI lower adjusted risk of all-cause mortality compared to men. Age-adjusted risk of death due to cardiovascular disease was similar in both genders and higher than risk of death due to cancer throughout the follow-up period