Body weight in adolescence and long-term risk of early heart failure in adulthood among men in Sweden.

AIMS: To study the relation between body mass index (BMI) in young men and risk of early hospitalization with heart failure. METHODS AND RESULTS: In a prospective cohort study, men from the Swedish Conscript Registry investigated 1968-2005 (n = 1 610 437; mean age, 18.6 years were followed 5-42 years (median, 23.0 years; interquartile range, 15.0-32.0), 5492 first hospitalizations for heart failure occurred (mean age at diagnosis, 46.6 (SD 8.0) years). Compared with men with a body mass index (BMI) of 18.5-20.0 kg/m2, men with a BMI 20.0-22.5 kg/m2 had an hazard ratio (HR) of 1.22 (95% CI, 1.10-1.35), after adjustment for age, year of conscription, comorbidities at baseline, parental education, blood pressure, IQ, muscle strength, and fitness. The risk rose incrementally with increasing BMI such that men with a BMI of 30-35 kg/m2 had an adjusted HR of 6.47 (95% CI, 5.39-7.77) and those with a BMI of ≥35 kg/m2 had an HR of 9.21 (95% CI, 6.57-12.92). The multiple-adjusted risk of heart failure per 1 unit increase in BMI ranged from 1.06 (95% CI, 1.02-1.11) in heart failure associated with valvular disease to 1.20 (95% CI, 1.18-1.22) for cases associated with coronary heart disease, diabetes, or hypertension. CONCLUSION: We found a steeply rising risk of early heart failure detectable already at a normal body weight, increasing nearly 10-fold in the highest weight category. Given the current obesity epidemic, heart failure in the young may increase substantially in the future and physicians need to be aware of this.

Body Weight in Adolescent Men in Sweden and Risk of an Early Acute Coronary Event: A Prospective Population-Based Study.

Background Coronary heart disease remains the dominant cause of death worldwide. To improve cardiovascular disease prevention, knowledge of early key risk factors, especially those that are modifiable, is essential. The ongoing global obesity epidemic is of particular concern. We aimed to determine whether body mass index at conscription predicts early acute coronary events among men in Sweden. Methods and Results This was a population-based Swedish cohort study of conscripts (n=1 668 921; mean age, 18.3 years; 1968-2005), with follow-up through linkage to the nationwide Swedish patient and death registries. Risk of a first acute coronary event (hospitalization for acute myocardial infarction or coronary death) during follow-up (1-48 years) was calculated with generalized additive models. Objective baseline measures of fitness and cognition were included in the models in secondary analyses. During follow-up, there were 51 779 acute coronary events, of which 6457 (12.5%) were fatal within 30 days. Compared with men at the lowest end of the normal body mass index spectrum (body mass index, 18.5 kg/m2), an increasing risk for a first acute coronary event was observed, with hazard ratios (HRs) peaking at 40 years of age. After multivariable adjustments, men with a body mass index of 35 kg/m2 had an HR of 4.84 (95% CI, 4.29-5.46) for an event before the age of 40 years. Conclusions An increased risk of an early acute coronary event was detectable within normal levels of body weight at the age of 18 years, increasing to almost 5-fold in the highest weight category at 40 years of age. Given increasing levels of body weight and prevalence of overweight and obesity in young adults, the current decrease in coronary heart disease incidence in Sweden may flatten or even reverse in the near future.

Do P2Y12 receptor inhibitors prescribed poststroke modify the risk of cognitive disorder or dementia? Protocol for a target trial using multiple national Swedish registries.

INTRODUCTION: The target of a class of antiplatelet medicines, P2Y12R inhibitors, exists both on platelets and on brain immune cells (microglia). This protocol aims to describe a causal (based on a counterfactual model) approach for analysing whether P2Y12R inhibitors prescribed for secondary prevention poststroke may increase the risk of cognitive disorder or dementia via their actions on microglia, using real-world evidence. METHODS AND ANALYSIS: This will be a cohort study nested within the Swedish National Health and Medical Registers, including all people with incident stroke from 2006 to 2016. We developed directed acyclic graphs to operationalise the causal research question considering potential time-independent and time-dependent confounding, using input from several experts. We developed a study protocol following the components of the target trial approach described by Hernan et al and describe the data structure that would be required in order to make a causal inference. We also describe the statistical approach required to derive the causal estimand associated with this important clinical question; that is, a time-to-event analysis for the development of cognitive disorder or dementia at 1, 2 and 5-year follow-up, based on approaches for competing events to account for the risk of all-cause mortality. Causal effect estimates and the precision in these estimates will be quantified. ETHICS AND DISSEMINATION: This study has been approved by the Ethics Committee of the University of Gothenburg and Confidentiality Clearance at Statistics Sweden with Dnr 937-18, and an approved addendum with Dnr 2019-0157. The analysis and interpretation of the results will be heavily reliant on the structure, quality and potential for bias of the databases used. When we implement the protocol, we will consider and document any biases specific to the dataset and conduct appropriate sensitivity analyses. Findings will be disseminated to local stakeholders via conferences, and published in appropriate scientific journals.

Cardiovascular fitness and risk of migraine: a large, prospective population-based study of Swedish young adult men.

OBJECTIVES: To examine the longitudinal relationship between cardiovascular fitness in young adult men and future risk of migraine and to estimate eventual differential effects among categories of body mass index (BMI) and blood pressure. DESIGN: National, prospective, population-based cohort study. SETTING: Sweden 1968-2014. PARTICIPANTS: 18-year-old Swedish men (n=1 819 828) who underwent mandatory military conscription examinations during the years 1968-2005. PRIMARY AND SECONDARY OUTCOMES: The primary outcome was the first dispensation of prescribed migraine-specific medication, identified using the Swedish Prescribed Drug Register. The secondary outcome was documented migraine diagnosis from the Swedish National Hospital Register. RESULTS: During follow-up, 22 533 men filled a prescription for migraine-specific medication. After confounding adjustment, compared with high cardiovascular fitness, low and medium fitness increased the risk of migraine-specific medication (risk ratio (RR)low: 1.29, 95% CI 1.24 to 1.35; population attributable fraction: 3.6%, 95% CI 1.7% to 5.3% and RRmedium: 1.15, 95% CI 1.12 to 1.19; population attributable fraction: 8.0%, 95% CI 4.0% to 11.7%). To assess potential effect measure modification, stratified analyses of these association by levels of BMI and blood pressure showed that lower fitness levels increased risk of migraine across all groups except among underweight men or men with high diastolic blood pressure. CONCLUSIONS: Young men with a lower cardiovascular fitness had a higher long-term risk of developing pharmacological prescription-requiring migraine. This study contributes with information regarding risk factors for migraine in men, an understudied population in migraine research.

The anti-asthmatic drug, montelukast, modifies the neurogenic potential in the young healthy and irradiated brain.

Brain tumors are the most common form of solid tumors in children. Due to the increasing number of survivors, it is of importance to prevent long-term treatment-induced side effects. Montelukast, a leukotriene receptor antagonist, may have the desired neuroprotective properties. The aim of the study was to determine whether montelukast could reduce adverse effects of cranial irradiation (CIR) to the young brain. Daily injections of montelukast or vehicle was given to young mice for 4 or 14 days in combination with CIR or under normal conditions. Montelukast treatment for 4 days protected against cell death with 90% more cell death in the vehicle group compared to the montelukast group 24 h after CIR. It also resulted in less microglia activation 6 h after CIR, where montelukast lowered the levels of CD68 compared to the vehicle groups. Interestingly, the animals that received montelukast for 14 days had 50% less proliferating cells in the hippocampus irrespective of receiving CIR or not. Further, the total number of neurons in the granule cell layer was altered during the sub-acute phase. The number of neurons was decreased by montelukast treatment in control animals (15%), but the opposite was seen after CIR, where montelukast treatment increased the number of neurons (15%). The results show beneficial effects by montelukast treatment after CIR in some investigated parameters during both the acute phase and with longer drug treatment. However, it also resulted in lower proliferation in the hippocampus under normal conditions, indicating that the effects of montelukast can be either beneficial or unfavorable, depending on the circumstances.

Risk factors in Swedish young men for amyotrophic lateral sclerosis in adulthood.

Recent research suggests that the incidence of amyotrophic lateral sclerosis (ALS) may be on the rise. Since ALS becomes predominant in later life, most studies on causal factors are conducted in middle-aged or older populations where potentially important influences from early life can usually not be adequately captured. We aimed to investigate predictors in young Swedish men for ALS in adulthood. Therefore, we performed a prospective cohort study of young men (aged 16-25, n = 1,819,817) who enlisted 1968-2005 and took part in comprehensive conscription examinations. Incident cases of ALS (n = 526) during up to 46 years of follow-up were identified in the National Hospital Register and Swedish Cause of Death Register. Those who developed ALS had lower BMI (body mass index) at conscription than their peers (p = 0.03). The risk of ALS during follow-up was calculated with Cox proportional hazards models. No associations were found with physical fitness, erythrocyte sedimentation rate, or non-psychotic mental disorders. Low overall muscle strength compared to high overall muscle strength [hazard ratio (HR) 1.36; 95% confidence interval (CI) 1.01-1.83] and low BMI (a one-unit increase HR 0.96; 95% CI 0.93-0.99) and lower erythrocyte volume fraction (a one-unit increase HR 0.96; 95% CI 0.92-0.998) were the statistically significant predictors for ALS in adjusted models. These findings provide novel epidemiologic evidence of a prospective association between low overall muscle strength and erythrocyte volume fraction in young men and ALS risk.

Cause-specific mortality in Swedish males diagnosed with non-psychotic mental disorders in late adolescence: a prospective population-based study.

BACKGROUND: While risk of premature death is most pronounced among persons with severe mental illness, also milder conditions are associated with increased all-cause mortality. We examined non-psychotic mental (NPM) disorders and specific causes of natural death in a cohort of late adolescent men followed for up to 46 years. METHODS: Prospective cohort study of Swedish males (n=1 784 626) who took part in structured conscription interviews 1968-2005. 74 525 men were diagnosed with NPM disorders at or prior to conscription. Median follow-up time was 26 years. HRs for cause-specific mortality were calculated using Cox proportional hazards models. RESULTS: Risks in fully adjusted models were particularly elevated for death by infectious diseases (depressive and neurotic/adjustment disorders (HR 2.07; 95% CI 1.60 to 2.67), personality disorders (HR 2.90; 95% CI 1.96 to 4.28) and alcohol-related and other substance use disorders (HR 9.02; 95% CI 6.63 to 12.27)) as well as by gastrointestinal causes (depressive and neurotic/adjustment disorders (HR 1.64; 95% CI 1.42 to 1.89), personality disorders (HR 2.77; 95% CI 2.27 to 3.38) and alcohol-related/substance use disorders (HR 4.41; 95% CI 3.59 to 5.42)). CONCLUSION: Young men diagnosed with NPM disorders had a long-term increased mortality risk, in particular due to infectious and gastrointestinal conditions. These findings highlight the importance of early preventive actions for adolescents with mental illness.

Striatal deafferentation increases dopaminergic neurogenesis in the adult olfactory bulb.

Dopaminergic loss is known to be one of the major hallmarks of Parkinson disease (PD). In addition to its function as a neurotransmitter, dopamine plays significant roles in developmental and adult neurogenesis. Both dopaminergic deafferentation and stimulation modulate proliferation in the subventricular zone (SVZ)/olfactory bulb system as well as in the hippocampus. Here, we study the impact of 6-hydroxydopamine (6-OHDA) lesions to the medial forebrain bundle on proliferation and neuronal differentiation of newly generated cells in the SVZ/olfactory bulb axis in adult rats. Proliferation in the SVZ decreased significantly after dopaminergic deafferentation. However, the number of neural progenitor cells expressing the proneuronal cell fate determinant Pax-6 increased in the SVZ. Survival and quantitative cell fate analysis of newly generated cells revealed that 6-OHDA lesions induced opposite effects in the two different regions of neurogenesis in the olfactory bulb: a transient decrease in the granule cell layer contrasts to a sustained increase of newly generated neurons in the glomerular layer. These data point towards a shift in the ratio of newly generated interneurons in the olfactory bulb layers. Dopaminergic neurogenesis in the glomerular layer tripled after lesioning and consistent with this finding, the total number of tyrosine hydroxylase (TH)-positive cells increased. Thus, loss of dopaminergic input to the SVZ led to a distinct cell fate decision towards stimulation of dopaminergic neurogenesis in the olfactory bulb glomerular layer. This study supports the accumulating evidence that neurotransmitters play a crucial role in determining survival and differentiation of newly generated neurons.