Annealing studies combined with low temperature emission Mössbauer spectroscopy of short-lived parent isotopes: Determination of local Debye-Waller factors.

An extension of the online implantation chamber used for emission Mössbauer Spectroscopy (eMS) at ISOLDE/CERN that allows for quick removal of samples for offline low temperature studies is briefly described. We demonstrate how online eMS data obtained during implantation at temperatures between 300 K and 650 K of short-lived parent isotopes combined with rapid cooling and offline eMS measurements during the decay of the parent isotope can give detailed information on the binding properties of the Mössbauer probe in the lattice. This approach has been applied to study the properties of Sn impurities in ZnO following implantation of 119In (T½ = 2.4 min). Sn in the 4+ and 2+ charge states is observed. Above T > 600 K, Sn2+ is observed and is ascribed to Sn on regular Zn sites, while Sn2+ detected at T < 600 K is due to Sn in local amorphous regions. A new annealing stage is reported at T ≈ 550 K, characterized by changes in the Sn4+ emission profile, and is attributed to the annihilation of close Frenkel pairs.

Topical moistening of mastectomy wounds with diluted tranexamic acid to reduce bleeding: randomized clinical trial.

BACKGROUND: Topical administration of tranexamic acid (TXA) may be an alternative to intravenous administration to reduce bleeding with a lower risk of systemic adverse events. The aim of this study was to investigate whether moistening a surgical wound with TXA before closure, leaving a thin film of drug only, would reduce postoperative bleeding. METHODS: This was a two-centre, stratified, parallel-group, placebo-controlled, double-blind RCT. Patients undergoing mastectomy with or without axillary lymph node clearance were randomized 1 : 1 to moistening of wound surface before closure with either 25 mg/ml TXA or 0·9 per cent sodium chloride (placebo). The primary endpoint was postoperative bleeding as measured by drain production in the first 24 h. Secondary endpoints were early haematoma, total drain production, postoperative complications and late aspirations of seroma within 3 months. RESULTS: Between 1 January 2016 and 31 August 2018, 208 patients were randomized. Two patients were converted to a different surgical procedure at surgery, and four did not receive the intervention owing to technical error. Thus, 202 patients were included in the study (101 in the TXA and 101 in the placebo group). TXA reduced mean drain production at 24 h (110 versus 144 ml; mean difference 34 (95 per cent c.i. 8 to 60) ml, P = 0·011). One patient in the TXA group had early haematoma compared with seven in the placebo group (odds ratio (OR) 0·13 (95 per cent c.i. 0·02 to 1·07); P = 0·057). There was no significant difference in postoperative complications between TXA and placebo (13 versus 10; OR 1·11 (0·45 to 2·73), P = 0·824) or need for late seroma aspirations (79 versus 67 per cent; OR 1·83 (0·91 to 3·68), P = 0·089). CONCLUSION: Moistening the wound with TXA 25 mg/ml before closure reduces postoperative bleeding within the first 24 h in patients undergoing mastectomy. Registration number: NCT02627560 (https://clinicaltrials.gov).

ANTECEDENTES: La administración tópica de ácido tranexámico (tranexamic acid, TXA) puede ser una alternativa a la administración por vía intravenosa para reducir la hemorragia, con menor riesgo de eventos sistémicos adversos. El objetivo de este estudio fue investigar si humedecer la herida quirúrgica con TXA 25 mg/ml antes del cierre de la incisión dejando solo una fina película de fármaco, reducía la hemorragia postoperatoria. MÉTODOS: Se trata de un ensayo clínico aleatorizado, a doble ciego, controlado con placebo, de grupos paralelos, estratificado por dos centros. Las pacientes sometidas a mastectomía con/sin resección de los ganglios linfáticos axilares se asignaron al azar 1:1 para la humidificación de la superficie de la herida antes del cierre con TXA 25 mg/ml o con NaCl al 0,9% (placebo). El objetivo primario fue la hemorragia postoperatoria medida por el débito del drenaje durante las primeras 24 horas. Los objetivos secundarios fueron el desarrollo de hematoma precoz, el débito total del drenaje, las complicaciones postoperatorias y la necesidad de aspiración de un seroma tardío durante los primeros 3 meses tras la cirugía. RESULTADOS: Entre el 1 de enero de 2016 y el 31 de agosto de 2018, 208 pacientes fueron asignadas al azar. En dos pacientes tuvo que realizarse un procedimiento quirúrgico diferente durante el periodo perioperatorio y cuatro pacientes no recibieron la intervención por errores técnicos. Por lo tanto, se incluyeron 202 pacientes en el estudio (101 fueron tratadas con TXA y 101 con placebo). El TXA redujo el débito medio del drenaje a las 24 horas (110 versus 144 ml, diferencia media 34 ml, i.c. del 95%: 8 a 60 ml, P = 0,010). Se presentó un hematoma precoz en una paciente del grupo del TXA versus siete pacientes tratadas con placebo (razón de oportunidades, odds ratio, OR 0,13, i.c. del 95% 0,02-1,07, P = 0,057). No hubo diferencias significativas en las complicaciones postoperatorias entre TXA y placebo (13 versus 10, OR 1,11, i.c. del 95% 0,45-2,73, P = 0,824) o la necesidad de aspiración tardía de seromas (79,3 versus 66,6%, OR 1,83, i.c. del 95% 0,91-3,68, P = 0,089). CONCLUSIÓN: Humedecer la herida antes del cierre con TXA 25 mg/ml reduce la hemorragia postoperatoria durante las primeras 24 horas en pacientes sometidas a mastectomía.

Local increase of the Curie temperature in Mn/Fe implanted Y3Fe5O12 (YIG).

The change in the Curie temperature of single crystalline garnet Y3Fe5O12 (YIG) sample due to lattice damage induced by ion implantation has been investigated in 57Fe emission Mössbauer Spectroscopy (eMS) following implantation of 57Mn (T½ = 1.5 min). The Mössbauer spectra analysis reveal high spin Fe3+ ions substituted on both the octahedral and the tetrahedral sites. Measurements in the temperature range 298 K-798 K show that average values of the magnetic hyperfine field are decreased by the implantation-induced damage on the local lattice structure of the YIG. The Curie temperature, however, is determined to be 651 ± 5 K, considerably higher than the value of bulk YIG (559 K). This is most likely due to lattice damage-induced changes on the spin configurations of YIG through a FeA-O-FeD distortion scheme.

Treatment as Prevention for Hepatitis C (TraP Hep C) - a nationwide elimination programme in Iceland using direct-acting antiviral agents.

A nationwide programme for the treatment of all patients infected with hepatitis C virus (HCV) was launched in Iceland in January 2016. By providing universal access to direct-acting antiviral agents to the entire patient population, the two key aims of the project were to (i) offer a cure to patients and thus reduce the long-term sequelae of chronic hepatitis C, and (ii) to reduce domestic incidence of HCV in the population by 80% prior to the WHO goal of HCV elimination by the year 2030. An important part of the programme is that vast majority of cases will be treated within 36 months from the launch of the project, during 2016-2018. Emphasis is placed on early case finding and treatment of patients at high risk for transmitting HCV, that is people who inject drugs (PWID), as well as patients with advanced liver disease. In addition to treatment scale-up, the project also entails intensification of harm reduction efforts, improved access to diagnostic tests, as well as educational campaigns to curtail spread, facilitate early detection and improve linkage to care. With these efforts, Iceland is anticipated to achieve the WHO hepatitis C elimination goals well before 2030. This article describes the background and organization of this project. Clinical trial number: NCT02647879.

Rare and Common Variants Conferring Risk of Tooth Agenesis.

We present association results from a large genome-wide association study of tooth agenesis (TA) as well as selective TA, including 1,944 subjects with congenitally missing teeth, excluding third molars, and 338,554 controls, all of European ancestry. We also tested the association of previously identified risk variants, for timing of tooth eruption and orofacial clefts, with TA. We report associations between TA and 9 novel risk variants. Five of these variants associate with selective TA, including a variant conferring risk of orofacial clefts. These results contribute to a deeper understanding of the genetic architecture of tooth development and disease. The few variants previously associated with TA were uncovered through candidate gene studies guided by mouse knockouts. Knowing the etiology and clinical features of TA is important for planning oral rehabilitation that often involves an interdisciplinary approach.

Atomic-scale study of the amorphous-to-crystalline phase transition mechanism in GeTe thin films.

The underlying mechanism driving the structural amorphous-to-crystalline transition in Group VI chalcogenides is still a matter of debate even in the simplest GeTe system. We exploit the extreme sensitivity of 57Fe emission Mössbauer spectroscopy, following dilute implantation of 57Mn (T½ = 1.5 min) at ISOLDE/CERN, to study the electronic charge distribution in the immediate vicinity of the 57Fe probe substituting Ge (FeGe), and to interrogate the local environment of FeGe over the amorphous-crystalline phase transition in GeTe thin films. Our results show that the local structure of as-sputtered amorphous GeTe is a combination of tetrahedral and defect-octahedral sites. The main effect of the crystallization is the conversion from tetrahedral to defect-free octahedral sites. We discover that only the tetrahedral fraction in amorphous GeTe participates to the change of the FeGe-Te chemical bonds, with a net electronic charge density transfer of ~ 1.6 e/a0 between FeGe and neighboring Te atoms. This charge transfer accounts for a lowering of the covalent character during crystallization. The results are corroborated by theoretical calculations within the framework of density functional theory. The observed atomic-scale chemical-structural changes are directly connected to the macroscopic phase transition and resistivity switch of GeTe thin films.

Charge states and lattice sites of dilute implanted Sn in ZnO.

The common charge states of Sn are 2+ and 4+. While charge neutrality considerations favour 2+ to be the natural charge state of Sn in ZnO, there are several reports suggesting the 4+ state instead. In order to investigate the charge states, lattice sites, and the effect of the ion implantation process of dilute Sn atoms in ZnO, we have performed 119Sn emission Mössbauer spectroscopy on ZnO single crystal samples following ion implantation of radioactive 119In (T ½ = 2.4 min) at temperatures between 96 K and 762 K. Complementary perturbed angular correlation measurements on 111mCd implanted ZnO were also conducted. Our results show that the 2+ state is the natural charge state for Sn in defect free ZnO and that the 4+ charge state is stabilized by acceptor defects created in the implantation process.

Historical epidemiology of hepatitis C virus (HCV) in select countries - volume 3.

Detailed, country-specific epidemiological data are needed to characterize the burden of chronic hepatitis C virus (HCV) infection around the world. With new treatment options available, policy makers and public health officials must reconsider national strategies for infection control. In this study of 15 countries, published and unpublished data on HCV prevalence, viraemia, genotype, age and gender distribution, liver transplants and diagnosis and treatment rates were gathered from the literature and validated by expert consensus in each country. Viraemic prevalence in this study ranged from 0.2% in Iran and Lebanon to 4.2% in Pakistan. The largest viraemic populations were in Pakistan (7 001 000 cases) and Indonesia (3 187 000 cases). Injection drug use (IDU) and a historically unsafe blood supply were major risk factors in most countries. Diagnosis, treatment and liver transplant rates varied widely between countries. However, comparison across countries was difficult as the number of cases changes over time. Access to reliable data on measures such as these is critical for the development of future strategies to manage the disease burden.

Magnetic self-organized atomic laminate from first principles and thin film synthesis.

The first experimental realization of a magnetic M(n+1)AX(n) (MAX) phase, (Cr(0.75)Mn(0.25))(2)GeC, is presented, synthesized as a heteroepitaxial single crystal thin film, exhibiting excellent structural quality. This self-organized atomic laminate is based on the well-known Cr(2)GeC, with Mn, a new element in MAX phase research, substituting Cr. The compound was predicted using first-principles calculations, from which a variety of magnetic behavior is envisaged, depending on the Mn concentration and Cr/Mn atomic configuration within the sublattice. The analyzed thin films display a magnetic signal at room temperature.

Fe charge state adjustment in ZnO upon ion implantation.

The influence of the ion implantation process on the charge state of dilute (57)Fe impurities implanted as radioactive (57)Mn in ZnO is investigated by (57)Fe emission Mössbauer spectroscopy. One sample is additionally implanted with stable (23)Na impurities. Both Fe(2+) and Fe(3+) charge states are observed, and the Fe(3+)/Fe(2+) ratio is found to increase with the fluence of both (57)Mn/(57)Fe and (23)Na ions, demonstrating that the build-up of Fe(3+) is not related to the chemical nature of the implanted ions. The results are interpreted in terms of radiation damage induced changes of the Fermi level, and illustrate that the Fe(3+)/Fe(2+) ratio can be adjusted by ion implantation. The spin-lattice relaxation time for Fe(3+) in ZnO is found to be independent of the implantation fluence, and is evidently an intrinsic property of the system.

Comparing resonant photon tunneling via cavity modes and Tamm plasmon polariton modes in metal-coated Bragg mirrors.

Resonant photon tunneling was investigated experimentally in multilayer structures containing a high-contrast (TiO(2)/SiO(2)) Bragg mirror capped with a semitransparent gold film. Transmission via a fundamental cavity resonance was compared with transmission via the Tamm plasmon polariton resonance that appears at the interface between a metal film and a one-dimensional photonic bandgap structure. The Tamm-plasmon-mediated transmission exhibits a smaller dependence on the angle and polarization of the incident light for similar values of peak transmission, resonance wavelength, and finesse. Implications for transparent electrical contacts based on resonant tunneling structures are discussed.

A magnetron sputtering system for the preparation of patterned thin films and in situ thin film electrical resistance measurements.

We describe a versatile three gun magnetron sputtering system with a custom made sample holder for in situ electrical resistance measurements, both during film growth and ambient changes on film electrical properties. The sample holder allows for the preparation of patterned thin film structures, using up to five different shadow masks without breaking vacuum. We show how the system is used to monitor the electrical resistance of thin metallic films during growth and to study the thermodynamics of hydrogen uptake in metallic thin films. Furthermore, we demonstrate the growth of thin film capacitors, where patterned films are created using shadow masks.

Ultrasound examination shows disturbed proximal gastric function in symptomatic gallstone patients with dyspepsia and improvement after cholecystectomy--gallstones and gastric emptying.

AIM: The aim of our study was to examine gastric function, gallbladder emptying, and dyspepsia in symptomatic gallbladder stone patients (SGBS) to see if a motility disorder, expressed by gastric function and gallbladder emptying, may cause dyspepsia in SBGS. MATERIALS AND METHODS: Gastric function and gallbladder emptying in 21 SGBS referred for surgical treatment were measured by ultrasound after ingestion of 500 ml of a meat soup (bouillon). Dyspeptic symptoms were simultaneously recorded on a Visual Analog Scale (VAS). The patients were re-examined 10 months after cholecystectomy. Hospital staff (n = 14) served as control subjects (C). RESULTS: In SGBS, the frontal diameter of the proximal stomach was wider than in C at both 10 minutes (55.7 vs. 48.3 mm; p = 0.053) and 20 minutes (49.3 vs. 39.5 mm; p = 0.002), and the sagittal area of the proximal stomach was larger at 10 minutes (25.0 vs. 20.9 cm (2); p = 0.03). The postprandial frontal diameter decreased significantly after cholecystectomy (immediately after the meal: 51.3 mm; p = 0.03, at 10 minutes: 47.6 mm; p = 0.05, and at 20 minutes: 39.1 mm; p = 0.004). Twenty minutes after meal ingestion, gallbladder emptying was significantly less in SGBS than in C with a mean (SD) emptying of 20 % (17) versus 33 % (18); p < 0.04. In the fasting state, SGBS felt more hunger than C (VAS 67 mm vs. 39 mm; p = 0.03). After cholecystectomy, the feeling of hunger decreased (VAS 27 mm; p = 0.01). CONCLUSION: SGBS had a wider proximal stomach and more hunger in the fasting state than C. After cholecystectomy the proximal stomach function and the hunger score improved. Our results suggest a physiological link between symptomatic gallstone disease and dyspepsia expressed by impaired proximal gastric function.

Changes in food tolerance and lifestyle after eradication of Helicobacter pylori.

BACKGROUND: It is known that patients with peptic ulcer disease (PUD) often have an unhealthy lifestyle that results in increased mortality because of smoking-related diseases. No thorough study has been done to see what changes, if any, the patient makes to lifestyle after eradication of Helicobacter pylori. METHODS: One-hundred-and-eighty-three patients were enrolled in an open-endoscopy setting; 58% had PUD and 42% gastritis and/or duodenitis (G/D). They filled out a lifestyle questionnaire before the start of anti-Helicobacter therapy and again 1 year later. RESULTS: The prevalence of food intolerance decreased from 71% to 44% among patients with PUD (P < 0.0001) and from 76% to 63% among patients with G/D (P = 0.09). Tolerance improved for coffee, orange juice, fried foods, spicy foods and fruits. There was no significant change in smoking or alcohol consumption after eradication. Coffee and tea consumption was unchanged. Milk consumption decreased from 4.2 dL/day to 3.3 (P = 0.01). The number of meals decreased from 3.5/day to 3.4 (P = 0.005) and snacking from 1.3 snacks/day to 1.1 (P = 0.02). Consumption of fruit increased from 4.0 to 4.3 times/week (P = 0.04), but the frequency of meat, fish, vegetables, spicy foods, salty foods, sweets and cakes did not change. The time spent on each meal was unchanged. There was no change in the time spent exercising. There were few significant differences between PUD and G/D patients. CONCLUSIONS: Food was better tolerated, but there were no major changes in lifestyle after eradication of H. pylori. Patients therefore do not abuse the privilege of a more tolerant digestion by indulging in a more unhealthy lifestyle.

Vagal tone and meal-induced abdominal symptoms in healthy subjects.

BACKGROUND/AIMS: Patients with functional dyspepsia often have meal-induced dyspeptic symptoms and low vagal tone. We examined whether these variables are related in healthy subjects. METHODOLOGY: In 40 healthy subjects vagal tone and abdominal symptoms were recorded before and after a 500-ml soup meal ingested in 1 and 4 min on separate visits. Vagal tone was indexed by respiratory sinus arrhythmia (RSA). RESULTS: Scores for nausea and discomfort were higher when the soup was ingested in 1 min as compared with 4 min (nausea: p = 0.02; discomfort: p = 0.04). There was no difference in fullness or abdominal pain. RSA was unrelated to meal-induced symptom scores. RSA varied with respiration and body position: It was highest while breathing deeply in the sitting position (24.0 beats/min). With normal breathing RSA was highest in the supine position (9.0 beats/min), lower while sitting (7.0 beats/min) and lowest while standing (6.2 beats/min). CONCLUSIONS: Epigastric discomfort in response to rapid ingestion of a test meal in healthy subjects was not related to vagal tone as indexed by RSA. Vagal tone varied with breathing pattern and body position. It is possible that increasing vagal tone by such measures can be beneficial in the treatment of patients with functional dyspepsia.

Chemical control of Penthaleus major (Acari: Prostigmata) in hayfields in Iceland.

The plant parasitic mite Penthaleus major (Dugès) occurs as a pest on perennial grasses in hayfields in Iceland, northern Norway, and southern Greenland. In these areas it appears as a summer phenomenon, contrary to more southern locations, where it appears as a pest on winter crops. Up to 500 individuals of P. major were collected per day in pitfall traps. Spring application of 44 ml/ha of permethrin and 5 ml of deltamethrin significantly reduced but did not eliminate the populations of P. major the following weeks. In addition to this immediate effect, spring application also decreased the mite populations in the fall and even the following spring. Additional effects might be obtained by earlier spring application. Despite a significant reduction in mite populations and reduction in visible plant damage, significant differences on dry matter yield were rarely registered. A side effect of application was a small but significant reduction in potassium-content of the yield, and the reduction in mite population was accompanied by a corresponding reduction in the number of spiders.

Patients with endoscopic gastritis and/or duodenitis improve markedly following eradication of Helicobacter pylori, although less so than patients with ulcers.

BACKGROUND: It is well documented that dyspepsia in patients with peptic ulcer disease (PUD) improves markedly after eradication of Helicobacter pylori, while rarely does it improve in patients with functional dyspepsia. There is a large group of H. pylori-infected patients who do not qualify for either diagnosis, but in whom eradication may be considered. The aim of this study was to compare symptom severity, change in gastrointestinal symptoms 1 year after eradication and satisfaction with therapy between PUD patients and patients with endoscopic diagnoses of gastritis and/or duodenitis (G/D patients). METHODS: The patients were randomized to one of four triple regimens containing ranitidine bismuth and metronidazole, and either oxytetracycline or spiramycine. Eradication was assessed with the 14C-urea breath test. GI symptoms were evaluated using the Gastrointestinal Symptom Rating Scale (GSRS) and the Ulcer Esophagitis Subjective Symptoms Scale (UESS) questionnaires. RESULTS: One-hundred-and-eighty-three patients were recruited from GI outpatient clinics. Patients with PUD and G/D had similar severity of symptoms before eradication therapy. One year after H. pylori eradication, 99% of the PUD patients and 75% of the G/D patients felt better regarding their main upper GI complaint. Abdominal pain score decreased by 48% as measured by GSRS and by 78% as measured by UESS in the PUD group and by 25% and 47%, respectively, in the G/D group. Reflux symptoms decreased by 41% and 63% in PUD patients and by 28% and 45% in G/D patients; indigestion by 30% and 47% in PUD and by 20% and 34% in G/D; eating discomfort by 60% in PUD and by 35% in G/D. Sleep quality score improved by 68% in PUD and by 41% in NU patients. Constipation decreased by 22% in the PUD group. All these differences in symptoms were highly significant compared to baseline. Diarrhoea was unchanged. CONCLUSIONS: Abdominal pain, reflux symptoms, indigestion and the ability to eat and sleep improved in both PUD and G/D patients 1 year after H. pylori eradication. Chronic diarrhoea was not induced. Abdominal pain improved significantly more in PUD than in G/D patients. Further study of the effect of H.pylori eradication in G/D patients is warranted.

Controversies in dyspepsia.

Even in the absence of visible lesions like an ulcer, cancer or oesophagitis, patients with functional dyspepsia may complain of severe dyspeptic symptoms and have a poor quality of life. Characteristically, these patients also often have a low estimate of their own health and have complaints from several organ systems. The cause of the disease is not known. Both central nervous system and gastric disturbances appear to be involved, and their relative importance is controversial. There is no clear beneficial effect of acid suppression or H. pylori eradication although effects of such therapy may be seen in minor subgroups. New findings emphasise the importance of distinguishing between functional dyspepsia and gastro-oesophageal reflux disease, which exhibit completely different gastric accommodation patterns to a meal and have very different therapeutic potential. The effect of drugs like glyceryl trinitrate, glucagon, sumatriptan and buspirone which all concomitantly improve symptoms and gastric accommodation support the important role of abnormal gastric accommodation to meals in patients with functional dyspepsia. A hypothetical model for the pathogenesis of functional dyspepsia is presented. It incorporates four established abnormalities: various psychological abnormalities, low vagal tone, impaired gastric relaxation, and visceral hypersensitivity, in a logical interplay along the brain-gut axis.

Genotype-phenotype interactions in Wilson's disease: insight from an Icelandic mutation.

Wilson's disease, an autosomal recessive disorder of copper transport, usually presents with symptoms from the liver or central nervous system. Rarely, the initial manifestation is fulminant hepatic failure. The abnormal gene (ATP7B) is located on chromosome 13q and encodes a copper-transporting ATPase. A large number of mutations have been reported. We describe a previously healthy 16-year-old girl who presented with fulminant hepatic failure. The girl died within 24 h of admission to a hospital from refractory shock. Autopsy revealed cirrhosis and widespread necrosis of the liver. The copper content of the liver was markedly increased (975 micrograms/g dry weight), strongly suggesting a diagnosis of Wilson's disease. Genetic studies revealed that the girl was homozygous for the mutation 2007 del7, which is the mutation found in all Wilson's disease patients previously identified in Iceland. This is the first known case of fulminant hepatic failure due to Wilson's disease in Iceland. Despite the same mutation, the clinical picture is vastly different from other Icelandic patients with Wilson's disease, who all presented with relatively late-onset neurological disease. This suggests that factors other than the specific mutation have significant impact on the phenotype of the disease.

[Changes in the prevalence of disability pension in Iceland 1976-1996.].

OBJECTIVE: To determine changes in the prevalence of disability pension in Iceland and to describe the distribution of those receiving disability pension according to gender, age and main diagnoses between the years 1976 and 1996. MATERIAL AND METHODS: The study includes all those receiving disability pension on the 1st of December in the years 1976 and 1996 as ascertained by the disability register at the State Social Security Institute of Iceland. There are two levels of disability pension, full disability pension (disability assessed as being more than 75%) and reduced disability pension (disability assessed as being 50% or 65%). Information on age and gender distribution of the Icelandic population was obtained. Age-standardized risk ratio between the years 1976 and 1996 was calculated for both pension levels combined and for full disability pension alone. RESULTS: There was no significant change in crude prevalence rate for both pension levels combined between the years 1976 and 1996, when the increase in the population was accounted for but without paying attention to changes in gender or age distribution. However, the standardized risk ratio showed a significantly decreased risk for both pension levels combined both for men and women in the year 1996 as compared with the year 1976, the age-standardized risk ratio being 0.95 and 0.93 respectively. It also showed a significant change between pension levels with an increased risk of full disability pension and a decreased risk of reduced disability pension. The increase in full disability pension was noted for both males and females and was largely independent of age. There was a significant increase in full disability pension in most disease categories. Disability due to diseases of the nervous system and sense organs and injury and poisoning increased amongst women only. A significant decrease in full disability pension due to infections and diseases of the digestive system occurred in both men and women. CONCLUSION: The prevalence of a disability pension amongst men and women in the year 1996 as compared to the year 1976 was significantly decreased when changes in population size and age distribution had been accounted for. This is particularly interesting because unemployment was increasing just prior to the year 1996. The prevalence of full disability pension had however significantly increased in 1996 compared with 1976. A plausible explanation for the observed change in disability pension levels is a pressure from the labour market, with increasing unemployment and competition. Also, the introduction of a disability card for those with full disability pension in 1980, which granted lower price for medication and the services of physicians, is likely to have increased the pressure for the higher level of disability pension (full disability pension). It seems unlikely that the increase in full disability pension and the decrease in reduced disability pension is due to a deterioration of health of the Icelandic population. Increased disability due to injury and poisoning amongst women is probably a result of their increased participation in the labour market. The decrease in disability due to infections is a result of a reduction in the number of cases of tuberculosis and poliomyelitis. The decrease in disability due to diseases of the digestive system is probably a result of improvement in the treatment of oesophageal reflux and peptic ulcer.