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Age, Academic Performance, and Stimulant Prescribing for ADHD: A Nationwide Cohort Study.

Sat, 01 Dec 2012 00:00:00 GMT

Title: Age, Academic Performance, and Stimulant Prescribing for ADHD: A Nationwide Cohort Study. Authors: Zoëga, Helga; Valdimarsdóttir, Unnur A; Hernández-Díaz, Sonia Abstract: BACKGROUND: We evaluated whether younger age in class is associated with poorer academic performance and an increased risk of being prescribed stimulants for attention-deficit/hyperactivity disorder (ADHD). METHODS: This was a nationwide population-based cohort study, linking data from national registries of prescribed drugs and standardized scholastic examinations. The study population comprised all children born in 1994-1996 who took standardized tests in Iceland at ages 9 and 12 (n = 11 785). We estimated risks of receiving low test scores (0-10th percentile) and being prescribed stimulants for ADHD. Comparisons were made according to children's relative age in class. RESULTS: Mean test scores in mathematics and language arts were lowest among the youngest children in the fourth grade, although the gap attenuated in the seventh grade. Compared with the oldest third, those in the youngest third of class had an increased relative risk of receiving a low test score at age 9 for mathematics (1.9; 95% confidence interval [CI] 1.6-2.2) and language arts (1.8; 95% CI 1.6-2.1), whereas at age 12, the relative risk was 1.6 in both subjects. Children in the youngest third of class were 50% more likely (1.5; 95% CI 1.3-1.8) than those in the oldest third to be prescribed stimulants between ages 7 and 14. CONCLUSIONS: Relative age among classmates affects children's academic performance into puberty, as well as their risk of being prescribed stimulants for ADHD. This should be taken into account when evaluating children's performance and behavior in school to prevent unnecessary stimulant treatment. Description: To access full text version of this article. Please click on the hyperlink "View/open" at the bottom of this page

Serúlóplasmín og járn. Tengsl við Alzheimersjúkdóm og Parkinsonsjúkdóm

Mon, 01 Oct 2012 00:00:00 GMT

Title: Serúlóplasmín og járn. Tengsl við Alzheimersjúkdóm og Parkinsonsjúkdóm Authors: Þorkell Jóhannesson; Jakob Kristinsson; Guðlaug Þórsdóttir; Jón Snædal Abstract: Ceruloplasmin, a multi-copper oxidase with four active copper atoms, oxidizes Fe2+ to Fe3+ and concomittantly fully reduces oxygen to water. The oxygenation of iron is a requisite for transferrin transport of iron and keeping noxious Fe2+ low. In the central nervous system (CNS) Cp is mostly localized in end feet of astrocytes surrounding capillaries and attached by a glycosylphosphatidylinositol-anchor. In aceruloplasminaemia, a rare recessive hereditary disease, complete loss of Cp is accompanied by disorders of iron metabolism and lesions in CNS and outside. In PD Cp concentration and oxidative activity in serum are significantly lowered with iron deposits and lesions in substantia nigra and basal ganglia. Changes in Cp-genes might be causative in these disorders. By inducing neuromelanin synthesis Cp may protect neurons in substantia nigra. In AD Cp activity in serum, but not concentration, is significantly lowered. Changes in Cp-genes have not been verified in AD. Total amounts of iron are not increased in AD brains although iron deposits and cortical lesions are numerous. Total copper is significantly lowered in AD brains. This may result in defective synthesis of Cp and other copper enzymes. - In conclusion, the defective Cp activity, associated with iron disorders, is seemingly of importance in PD and also in AD with other copper enzyme defects possibly involved.; Serúlóplasmín (Cp) er svokallaður multi-kopar oxídasi, sem in vivo oxar Fe2+ í Fe3+ og afoxar jafnframt súrefni að fullu í vatn. Cp tryggir að Fe3+ geti bundist transferríni og að magn hvarfgjarns Fe2+ haldist í lágmarki. Í miðtaugakerfinu er það einkum bundið örmum stirnufrumna með glýkósýlfosfatidýlinósítól-tengi í námunda við æðar. Í Cp eru fjögur virk koparatóm og er festing þeirra óskylt ferli myndunar próteinhluta ensímsins. Í Cp-þurrð í blóði (aserúlóplasmínemía) er alger vöntun á Cp og áberandi járnraskanir í miðtaugakerfinu og utan þess. Í Parkinsonsjúkdómi (PD) er bæði Cp-þéttni og oxunarvirkni í sermi minnkuð, samfara áberandi járnsöfnun í svartsviðið í miðheila. Cp gæti hamlað uppkomu PD með því að binda járn í neurómelaníni og varna oxunarskemmdum í orkukornum taugunga í svartsviði. Ríkur erfðaþáttur er í PD og breytingar í Cp-genum gætu tengst erfðamynstrinu. Í Alzheimersjúkdómi (AD) er oxunarvirkni Cp minnkuð í sermi, en ekki þéttni þess. Breytingar í Cp-genum virðast ekki tengjast AD. Við AD eru bæði járnraskanir og vöntun á kopar í heilanum. Koparskortur gæti valdið truflun á myndun virks Cp auk annarra koparensíma í heila. Ætla má að trufluð Cp-virkni, og þar með raskaður járnbúskapur, skipti máli við PD og við AD ásamt hugsanlega truflunum á öðrum koparensímum. Description: Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/Open Allur texti - Full text

Psoriatic arthritis and onycholysis -- results from the cross-sectional Reykjavik psoriatic arthritis study.

Sun, 01 Jul 2012 00:00:00 GMT

Title: Psoriatic arthritis and onycholysis -- results from the cross-sectional Reykjavik psoriatic arthritis study. Authors: Love, Thorvardur Jon; Gudjonsson, Johann Eli; Valdimarsson, Helgi; Gudbjornsson, Bjorn Abstract: OBJECTIVE: To measure the associations between subtypes of nail changes and psoriatic arthritis (PsA) among patients with psoriasis. METHODS: Patients age 18 years and older with active psoriasis were examined for skin and nail changes and asked if they had been diagnosed with PsA. Patients with arthritis were invited for a separate study 1-6 years after their initial visit. Univariate and multivariate analyses were used to test the strength of associations between subtypes of nail changes and arthritis. RESULTS: Of 1116 patients with psoriasis, 37% (95% CI 34%-40%) had nail changes. Age, any nail change, onycholysis, and pitting were each associated with PsA on univariate analysis. Multivariate analysis showed that onycholysis was the only type of nail change independently associated with PsA (OR 2.05, p < 0.001). Nail changes persisted and had increased in prevalence at the followup examination at a mean of 3.8 (median 4 yrs, interquartile range 3-4) years later. Previously reported associations between psoriasis location and arthritis were not seen in this dataset. CONCLUSION: PsA is associated with onycholysis. Associations with pitting and subungual hyperkeratosis were not statistically significant. Subtypes of nail changes should be analyzed separately in future studies of PsA. Description: To access publisher full text version of this article. Please click on the hyperlink in Additional Links field.

The interaction of obstructive sleep apnea and obesity on the inflammatory markers C-reactive protein and interleukin-6: the Icelandic Sleep Apnea Cohort.

Sun, 01 Jul 2012 00:00:00 GMT

Title: The interaction of obstructive sleep apnea and obesity on the inflammatory markers C-reactive protein and interleukin-6: the Icelandic Sleep Apnea Cohort. Authors: Arnardottir, Erna S; Maislin, Greg; Schwab, Richard J; Staley, Bethany; Benediktsdottir, Bryndis; Olafsson, Isleifur; Juliusson, Sigurdur; Romer, Micah; Gislason, Thorarinn; Pack, Allan I Abstract: STUDY OBJECTIVES: To assess the relative roles and interaction of obstructive sleep apnea (OSA) severity and obesity on interleukin-6 (IL-6) and C-reactive protein (CRP) levels. DESIGN: Cross-sectional cohort. SETTING: The Icelandic Sleep Apnea Cohort. PARTICIPANTS: 454 untreated OSA patients (380 males and 74 females), mean ± standard deviation age 54.4 ± 10.6 yr. MEASUREMENTS AND RESULTS: Participants underwent a sleep study, abdominal magnetic resonance imaging to measure total abdominal and visceral fat volume, and had fasting morning IL-6 and CRP levels measured in serum. A significantly higher correlation was found for BMI than visceral fat volume with CRP and IL-6 levels. Oxygen desaturation index, hypoxia time, and minimum oxygen saturation (SaO₂) significantly correlated with IL-6 and CRP levels, but apnea-hypopnea index did not. When stratified by body mass index (BMI) category, OSA severity was associated with IL-6 levels in obese participants only (BMI > 30 kg/m²). A multiple linear regression model with interaction terms showed an independent association of OSA severity with IL-6 levels and an interaction between OSA severity and BMI, i.e., degree of obesity altered the relationship between OSA and IL-6 levels. An independent association of OSA severity with CRP levels was found for minimum SaO₂ only. A similar interaction of OSA severity and BMI on CRP levels was found for males and postmenopausal women. CONCLUSIONS: OSA severity is an independent predictor of levels of IL-6 and CRP but interacts with obesity such that this association is found only in obese patients. Description: To access publisher full text version of this article. Please click on the hyperlink in Additional Links field.