P5743Overweight and obesity in adolescent men in Sweden and risk of early stroke

Background

Increasing numbers of stroke cases in the young are reported in many countries, potentially at least partly due to rising rates of overweight and obesity. Most data on the effect of obesity on stroke is derived from middle aged populations; there is a comparative lack of information on the effect of excessive body weight in young people.

Purpose

We aimed to determine whether body mass index (BMI) at age 18 predicted early stroke events among men in Sweden.

Methods

Population-based Swedish cohort study of conscripts (n=1,668,921; mean age at baseline, 18.3 years) who enlisted during 1968–2005. Follow-up was done through linkage to the nationwide Swedish patient and death registries. Risk of a first hospitalization for stroke (any type) during follow-up (5–46 years) was calculated with Cox proportional hazards models. Objective baseline measures of fitness and cognition were included in the models in a second set of analyses.

Results

During follow-up there were 12,512 first hospitalizations for stroke (mean age at diagnosis, 48.5 (SD 9.4) years, maximum 64 years). Compared with men with BMI of 18.5 to 20.0 kg/m2, men with BMI 20 to <22.5 and 22.5 to <25.0 kg/m2 had hazard ratios (HR) of 1.06 (1.00–1.12) and 1.23 (1.14–1.31), respectively, for hospitalization for stroke, after adjustment for age, year of conscription, comorbidities at baseline, parental education, blood pressure, IQ, muscle strength, and fitness. Those with a BMI of ≥35 kg/m2 had an HR of 3.33 (2.46–4.51) for an event before the age of 65, compared to slim men. The multiple-adjusted risk per 1-unit increase in BMI was 1.07 (95% CI, 1.06–1.08).

Conclusion

We found a rise in risk of early hospitalisation for stroke detectable already at normal levels of body weight at age 18, and rising to more than 3-fold in the highest weight category. Given increasing levels of body weight, and prevalence of overweight, obesity, and severe obesity in young adults, the increased incidence of stroke in the young may potentially partly be explained by rising body weight, with an obvious potential for prevention.

4949Diverging secular trends in cardiovascular disease 21-year incidence in Swedish men born in 1950–1978

Background

Cardiovascular disease (CVD) mortality is decreasing in Western countries, including Sweden. However, there are reports of increases in incidence in young people with respect to heart failure (HF) and atrial fibrillation (AF). The magnitude and causes of these changes are only partly known.

Aims

We investigated secular trends in incidence in CVD outcomes and their attenuation by changes in body mass index (BMI). The outcomes were risk of acute myocardial infarction (AMI), heart failure (HF) and atrial fibrillation (AF) as well as cardiovascular and all-cause death in a population of Swedish adolescents.

Methods

We followed a cohort of Swedish men enrolled for military service conscription in 1969–1996 (n=1,326,082; mean age=18.3) until December 2016, collected from the national inpatient (IPR) and outpatient registries (OPR). Cox-proportional hazard models were used to analyse the longitudinal change in incidence by with respect to early (0–21 years) of follow-up for subgroups with conscription 1968–1971, 1971–1976, 1976–1981, 1981–1986, 1986–1991, 1991–1996 (with the group born 1971–1976 as reference). Adjustments for potential confounders including BMI were performed.

Results

We found that CVD and all-cause mortality and MI decreased progressively during the follow-up with hazard ratios (HR) of 0.51, 95% confidence interval (CI) 0.43–0.62, HR 0.51 CI 0.57–0.62, and 0.60 CI 0.50–0.72, respectively. In contrast, we found increases in the incidence of HF (HR 1.86, CI 1.48–2.33], and AF (HR 8.26, CI 6.87–9.92). Adjustments for changes in BMI partly attenuated the changes in secular trends. Cubic spline models showed where the changes in secular trends were most prominent.

Conclusion

The incidences of cardiovascular outcomes show diverging secular changes. While MI and cardiovascular mortality are continually decreasing, there is an increase in HF and AF. The associations appear to be partly explained by changes in index BMI over time.

Acknowledgement/Funding

grants from the Swedish Government and the county councils, the ALF–GBG-719761, ALFGBG-751111, Swedish Stroke Association, Göteborg Medical Society

Strong UV absorption and visible luminescence in ytterbium-doped aluminosilicate glass under UV excitation

A broad visible luminescence band and characteristic IR luminescence of Yb(3+) ions are observed under UV excitation in ytterbium-doped aluminosilicate glass. Samples made under both oxidizing and reducing conditions are analyzed. A strong charge-transfer absorption band in the UV range is observed for glass samples containing ytterbium. Additional absorption bands are observed for the sample made under reducing conditions, which are associated with f-d transitions of divalent ytterbium. The visible luminescence band is attributed to 5d-4f emission from Yb(2+) ions, and the IR luminescence is concluded to originate from a relaxed charge-transfer transition. The findings are important to explain induced optical losses (photodarkening) in high-power fiber lasers.

Protective and regenerative effects of the GH/IGF-I axis on the brain

Apart from regulating somatic growth and metabolism, evidence suggest that the GH/ IGF-I axis is involved in the regulation of brain growth, development and myelination. Moreover, growth hormone (GH) and particularly IGF-I have been attributed neuroprotective effects in different in vitro and in vivo experimental models. In addition, both GH and IGF-I affect cognition and biochemistry in the adult brain. Some of the effects of GH are suggested to be mediated by circulating IGF-I, while other effects may be due to locally produced IGF-I within the brain. It is also possible that GH may act directly on the central nervous system (CNS) without involving IGF-I (either circulating or locally). Plasticity in the CNS may be viewed as changes in the functional interplay between the major cell types neurons, astrocytes and oligodendrocytes. GH and IGF-I affect all these cell types in several aspects. Apart from neuroprotective effects of GH and IGF-I in different experimental models of CNS injury, IGF-I has been found to increase progenitor cell proliferation and new neurons, oligodendrocytes, and blood vessels in the dentate gyrus of the hippocampus. In the adult cerebral cortex, it appears that only oligodendrogenesis is affected. The increase of IGF-I on endothelial cell phenotype may explain the increase in cerebral arteriole density observed after GH treatment. In the present review, different aspects of the GH/IGF-I axis effects on the brain will be discussed with particular emphasis on neuroprotection, regeneration and brain plasticity. Moreover, recent findings describing neuroprotective effects and effects on synaptic plasticity by GH secretagogues will be reviewed.

Origin of magnetic anisotropy of Gd metal

Using first-principles theory, we have calculated the energy of Gd as a function of spin direction, theta, between the c and a axes and found good agreement with experiment for both the total magnetic anisotropy energy and its angular dependence. The calculated low temperature direction of the magnetic moment lies at an angle of 20 degrees to the c axis. The calculated magnetic anisotropy energy of Gd metal is due to a unique mechanism involving a contribution of 7.5 microeV from the classical dipole-dipole interaction between spins plus a contribution of 16 microeV due to the spin-orbit interaction of the conduction electrons. The 4f spin polarizes the conduction electrons via exchange interaction, which transfers the magnetic anisotropy of the conduction electrons to the 4f spin.

Leukotriene and prostanoid pathway enzymes in bronchial biopsies of seasonal allergic asthmatics

Cysteinyl-leukotrienes and prostaglandin D2 generated by the 5-lipoxygenase (5-LO) and cyclooxygenase (COX) pathways, respectively, cause bronchoconstriction, leukocyte recruitment, and bronchial hyperresponsiveness in asthma. We characterized the cellular expression of 5-LO and COX enzymes using immunohistochemistry on bronchial biopsies from 12 allergic asthmatic patients before and during seasonal exposure to birch pollen. Bronchial responsiveness (p = 0.004) and symptoms (p < 0.005) increased and peak expiratory flow (PEF; p < or = 0.02) decreased in the pollen season. In-season biopsies had 2-fold more cells immunostaining for 5-LO (p = 0.02), 5-LO-activating protein (FLAP; p = 0.04), and leukotriene (LT)A4 hydrolase (p = 0.05), and 4-fold more for the terminal enzyme for cysteinyl-leukotriene synthesis, LTC4 synthase (p = 0.02). Immunostaining for COX-1, COX-2, and PGD2 synthase was unchanged. Increased staining for LTC4 synthase was due to increased eosinophils (p = 0.035) and an increased proportion of eosinophils expressing the enzyme (p = 0.047). Macrophages also increased (p = 0.019), but mast cells and T-lymphocyte subsets were unchanged. Inverse correlations between PEF and 5-LO(+) cell counts link increased expression of 5-LO pathway enzymes in eosinophils and macrophages within the bronchial mucosa to deterioration of lung function during seasonal allergen exposure.