Development of a Multivariable Model to Predict the Need for Bone Marrow Sampling in Persons With Monoclonal Gammopathy of Undetermined Significance : A Cohort Study Nested in a Clinical Trial.

BACKGROUND: Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) are asymptomatic precursor conditions to multiple myeloma and related disorders. Smoldering multiple myeloma is distinguished from MGUS by 10% or greater bone marrow plasma cells (BMPC) on sampling, has a higher risk for progression, and requires specialist management. OBJECTIVE: To develop a multivariable prediction model that predicts the probability that a person with presumed MGUS has 10% or greater BMPC (SMM or worse by bone marrow criteria) to inform the decision to obtain a bone marrow sample and compare its performance to the Mayo Clinic risk stratification model. DESIGN: iStopMM (Iceland Screens, Treats or Prevents Multiple Myeloma), a prospective population-based screening study of MGUS. (ClinicalTrials.gov: NCT03327597). SETTING: Icelandic population of adults aged 40 years or older. PATIENTS: 1043 persons with IgG, IgA, light-chain, and biclonal MGUS detected by screening and an interpretable bone marrow sample. MEASUREMENTS: Monoclonal gammopathy of undetermined significance isotype; monoclonal protein concentration; free light-chain ratio; and total IgG, IgM, and IgA concentrations were used as predictors. Bone marrow plasma cells were categorized as 0% to 4%, 5% to 9%, 10% to 14%, or 15% or greater. RESULTS: The c-statistic for SMM or worse was 0.85 (95% CI, 0.82 to 0.88), and calibration was excellent (intercept, -0.07; slope, 0.95). At a threshold of 10% predicted risk for SMM or worse, sensitivity was 86%, specificity was 67%, positive predictive value was 32%, and negative predictive value was 96%. Compared with the Mayo Clinic model, the net benefit for the decision to refer for sampling was between 0.13 and 0.30 higher over a range of plausible low-risk thresholds. LIMITATION: The prediction model will require external validation. CONCLUSION: This accurate prediction model for SMM or worse was developed in a population-based cohort of persons with presumed MGUS and may be used to defer bone marrow sampling and referral to hematology. PRIMARY FUNDING SOURCE: International Myeloma Foundation and the European Research Council.

Association Between Autoimmune Diseases and Monoclonal Gammopathy of Undetermined Significance : An Analysis From a Population-Based Screening Study.

BACKGROUND: Monoclonal gammopathy of undetermined significance (MGUS) is a precursor of multiple myeloma (MM) and related conditions. In previous registry-based, retrospective studies, autoimmune diseases have been associated with MGUS. However, these studies were not based on a screened population and are therefore prone to ascertainment bias. OBJECTIVE: To examine whether MGUS is associated with autoimmune diseases. DESIGN: A cross-sectional study within iStopMM (Iceland Screens, Treats, or Prevents MM), a prospective, population-based screening study of MGUS. SETTING: Icelandic population of adults aged 40 years or older. PATIENTS: 75 422 persons screened for MGUS. MEASUREMENTS: Poisson regression for prevalence ratios (PRs) of MGUS among persons with or without an autoimmune disease, adjusted for age and sex. RESULTS: A total of 10 818 participants had an autoimmune disorder, of whom 599 had MGUS (61 with a prior clinical diagnosis and 538 diagnosed at study screening or evaluation). A diagnosis of an autoimmune disease was not associated with MGUS (PR, 1.05 [95% CI, 0.97 to 1.15]). However, autoimmune disease diagnoses were associated with a prior clinical diagnosis of MGUS (PR, 2.11 [CI, 1.64 to 2.70]). LIMITATION: Registry data were used to gather information on autoimmune diseases, and the homogeneity of the Icelandic population may limit the generalizability of these results. CONCLUSION: The study did not find an association between autoimmune disease and MGUS in a systematically screened population. Previous studies not done in systematically screened populations have likely been subject to ascertainment bias. The findings indicate that recommendations to routinely screen patients with autoimmune disease for MGUS may not be warranted. PRIMARY FUNDING SOURCE: The International Myeloma Foundation and the European Research Council.

Successful treatment of extreme hyponatremia in an anuric patient using continuous venovenous hemodialysis.

Rapid correction of severe hyponatremia can result in osmotic demyelination syndrome. Patients with severe hyponatremia and renal failure requiring dialysis pose a therapeutic challenge since the use of conventional intermittent hemodialysis will result in a rapid correction of the serum sodium level. We report the case of a 52-year-old woman with extreme hyponatremia and severe acute kidney injury, who was successfully treated with continuous venovenous hemodialysis using a modified dialysate solution with a low sodium concentration that was adjusted on a daily basis.

Defining new reference intervals for serum free light chains in individuals with chronic kidney disease: Results of the iStopMM study.

Serum free light chain (FLC) concentration is greatly affected by kidney function. Using a large prospective population-based cohort, we aimed to establish a reference interval for FLCs in persons with chronic kidney disease (CKD). A total of 75422 participants of the iStopMM study were screened with serum FLC, serum protein electrophoresis and immunofixation. Estimated glomerular filtration rate (eGFR) was calculated from serum creatinine. Central 99% reference intervals were determined, and 95% confidence intervals calculated. Included were 6461 (12%) participants with measured FLCs, eGFR < 60 mL/min/1.73 m2, not receiving renal replacement therapy, and without evidence of monoclonality. Using current reference intervals, 60% and 21% had kappa and lambda FLC values outside the normal range. The FLC ratio was outside standard reference interval (0.26-1.65) in 9% of participants and outside current kidney reference interval (0.37-3.10) in 0.7%. New reference intervals for FLC and FLC ratio were established. New reference intervals for the FLC ratio were 0.46-2.62, 0.48-3.38, and 0.54-3.30 for eGFR 45-59, 30-44, and < 30 mL/min/1.73 m2 groups, respectively. The crude prevalence of LC-MGUS in CKD patients was 0.5%. We conclude that current reference intervals for FLC and FLC ratio are inaccurate in CKD patients and propose new eGFR based reference intervals to be implemented.

Mild Stage 1 post-operative acute kidney injury: association with chronic kidney disease and long-term survival.

BACKGROUND: Mild cases of acute kidney injury (AKI) are identified by a small rise in serum creatinine (SCr) according to the KDIGO AKI definition. The aim of this study was to examine the long-term outcomes of individuals with mild AKI.Methods. This was a retrospective cohort study of all adult patients who underwent abdominal, cardiothoracic, vascular or orthopaedic surgery at Landspitali-The National University Hospital of Iceland in 1998-2015. Incident chronic kidney disease (CKD), progression of pre-existing CKD and long-term survival were compared between patients with mild Stage 1 AKI (defined as a rise in SCr of ≥26.5 µmol/L within 48 h post-operatively without reaching 1.5× baseline SCr within 7 days), and a propensity score-matched control group without AKI stratified by the presence of CKD. RESULTS: Pre- and post-operative SCr values were available for 47 333 (42%) surgeries. Of those, 1161 (2.4%) had mild Stage 1 AKI and 2355 (5%) more severe forms of AKI. Mild Stage 1 AKI was associated with both incident CKD and progression of pre-existing CKD (P < 0.001). After exclusion of post-operative deaths within 30 days, mild Stage 1 AKI was not associated with worse 1-year survival in patients with preserved kidney function (94% versus 94%, P = 0.660), and same was true for patients with pre-operative CKD (83% versus 82%, P = 0.870) compared with their matched individuals. Conclusions. Mild Stage 1 AKI is associated with development and progression of CKD, but not with inferior 1-year survival. These findings support the inclusion of a small absolute increase in SCr in the definition of AKI.

Iceland screens, treats, or prevents multiple myeloma (iStopMM): a population-based screening study for monoclonal gammopathy of undetermined significance and randomized controlled trial of follow-up strategies.

Monoclonal gammopathy of undetermined significance (MGUS) precedes multiple myeloma (MM). Population-based screening for MGUS could identify candidates for early treatment in MM. Here we describe the Iceland Screens, Treats, or Prevents Multiple Myeloma study (iStopMM), the first population-based screening study for MGUS including a randomized trial of follow-up strategies. Icelandic residents born before 1976 were offered participation. Blood samples are collected alongside blood sampling in the Icelandic healthcare system. Participants with MGUS are randomized to three study arms. Arm 1 is not contacted, arm 2 follows current guidelines, and arm 3 follows a more intensive strategy. Participants who progress are offered early treatment. Samples are collected longitudinally from arms 2 and 3 for the study biobank. All participants repeatedly answer questionnaires on various exposures and outcomes including quality of life and psychiatric health. National registries on health are cross-linked to all participants. Of the 148,704 individuals in the target population, 80 759 (54.3%) provided informed consent for participation. With a very high participation rate, the data from the iStopMM study will answer important questions on MGUS, including potentials harms and benefits of screening. The study can lead to a paradigm shift in MM therapy towards screening and early therapy.

Monoclonal gammopathy of undetermined significance and COVID-19: a population-based cohort study.

Multiple myeloma (MM) patients have increased risk of severe coronavirus disease 2019 (COVID-19) when infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Monoclonal gammopathy of undetermined significance (MGUS), the precursor of MM has been associated with immune dysfunction which may lead to severe COVID-19. No systematic data have been published on COVID-19 in individuals with MGUS. We conducted a large population-based cohort study evaluating the risk of SARS-CoV-2 infection and severe COVID-19 among individuals with MGUS. We included 75,422 Icelanders born before 1976, who had been screened for MGUS in the Iceland Screens Treats or Prevents Multiple Myeloma study (iStopMM). Data on SARS-CoV-2 testing and COVID-19 severity were acquired from the Icelandic COVID-19 Study Group. Using a test-negative study design, we included 32,047 iStopMM participants who had been tested for SARS-CoV-2, of whom 1754 had MGUS. Among these participants, 1100 participants, tested positive, 65 of whom had MGUS. Severe COVID-19 developed in 230 participants, including 16 with MGUS. MGUS was not associated with SARS-CoV-2 infection (Odds ratio (OR): 1.05; 95% confidence interval (CI): 0.81-1.36; p = 0.72) or severe COVID-19 (OR: 0.99; 95%CI: 0.52-1.91; p = 0.99). These findings indicate that MGUS does not affect the susceptibility to SARS-CoV-2 or the severity of COVID-19.

[Patient satisfaction with care and interaction with staff in the Acute Cardiac Unit at Landspitali - The National University Hospital of Iceland]. / Vidhorf sjúklinga til veittrar þjónustu og vidmóts heilbrigdisstarfsfólks á Hjartgátt Landspítala.

INTRODUCTION: The Icelandic health care system ranks favourably in international comparison but patients' experience of interaction with the health service has not been well studied. The goal of this study was to examine the satisfaction of patients admitted to the Acute Cardiac Unit (ACU) at Landspitali - The National University Hospital of Iceland. METHODS: A questionnaire based on the Patient Satisfaction Questionnaire III was mailed to patients admitted to the ACU between 1 January and 29 February 2012. Questions were presented as statements and participants asked to respond how strongly on a scale from 1 to 5 they agreed or disagreed with each statement. Data analysis was performed using descriptive statistics, Cronbach´s alpha for internal consistency of scales and principal components analysis, Wilcoxon-Mann-Whitney and Kruskal-Wallis tests for comparison of groups and Pearson and Spearman correlation coefficients for correlation between variables. RESULTS: The questionnaire was mailed to 485 individuals of whom 275 (57%) responded. The median age of the participants was 62 (range, 19-95) years and 132 (48%) were women. Internal consistency of the scales was mostly high (Cronbach's alpha 0.62-0.91) and principal components analysis revealed one main factor. The mean score of the questionnaire was 6.8 ±1.0 and 91%, and 86% of the participants were pleased with their interaction with physicians and nurses, respectively. Similarly, 88% were pleased with the care they recieved but 25% felt they received insufficient explanations of their symptoms or that follow-up care was lacking. CONCLUSION: Patients of the ACU generally appear to be satisfied with their care. However, our results suggest that improvement is needed in several areas, including information provided at discharge and follow-up care.

[Epidemiology of acute kidney injury in a tertiary care university hospital according to the RIFLE criteria]. / Bradur nyrnaskadi a Landspitala 2008-2011 og ahaettupaettir og afdrif sjuklinga med alvarlegan skada.

INTRODUCTION: Acute kidney injury (AKI) is a common problem in hospitalized patients, requiring extensive treatment and carries a high mortality rate. This study was designed to assess the epidemiology of AKI, and risk factors and outcome of patients with severe AKI in a tertiary care university hospital in Iceland. MATERIAL AND METHODS: All adult patients with measured serum creatinine (SCr) in Landspitali University Hospital from January 2008 to December 2011, who had a measured baseline SCr in the preceeding six months, were included. Patients were categorized according to the RIFLE-criteria into risk (stage 1), injury (stage 2) and failure (stage 3) groups based on their highest SCr, using the lowest SCr in the previous six months as baseline. RESULTS: A total of 17,693 individuals (out of 74,960) had a baseline SCr and their data were used for analysis. AKI occurred in 3,686 (21%) with 12%, 5% and 4% of stage 1, 2 and 3, respectively. There were more females in stage 1 and stage 2 and more males in stage 3 (p< 0.001). Contributing causes for AKI in patients with stage 3 AKI were surgery (22%), circulatory shock (23%), sepsis (14%), cardiovascular insult (32%), respiratory failure (27%), bleeding (10%), trauma (7%) and AKI associated drugs (61%). Dialysis was required in 11% and in 0.7% for longer than 30 days but none > 90 days. One year survival was 52%. CONCLUSIONS: Acute kidney injury is common in Iceland and the prognosis of those with severe AKI is dismal. Majority of those patients were taking drugs that increase risk of AKI, providing a target for preventive measures.

[Bone mineral density of young women with history of anorexia nervosa]. / Beinthéttni ungra kvenna med sögu um lystarstol.

OBJECTIVE: A decrease in bone mineral density (BMD) is frequently seen in patients with anorexia nervosa (AN). This study was designed to assess BMD of young Icelandic women with current or previous history of AN and identify predictors which might be targets for preventive measures. MATERIAL AND METHODS: The study was retrospective. Participants were women aged 18-40 years, with diagnosis of AN (F50.0, F50.1) attending the anorexia unit at Landspítali - The National University Hospital of Iceland - in 2001-2009, who had undergone measurement of BMD by dual-energy X-ray absorptiometry. A control group consisted of 58 healthy 30 years old women participating in a study of bone health in 2001-2003. RESULTS: At time of BMD measurement the median body mass index (BMI: kg/m2) in the AN group (n=40) was 17.4 (12.3-25.2) compared to 23.6 (18.1-43.7) in the control group (p<0,001). Lumbar spine and hip BMD were 15.3-17.5% lower in AN patients than in control subjects (p<0.001). In both groups there was a strong correlation between BMD and body weight (r=0.354-0.604, p<0.05) and lean mass (r=0.425-0.588, p<0.05). Among patients with AN a correlation was also seen between BMD and lowest weight during the illness (r=0.482-0.499, p<0.01). Among the 26 AN patients who had repeated BMD measurement, a significant decrease in BMD at femoral neck (-6.6%, p=0.030) was observed in those who lost weight between the measurements (n=9). Those who had BMI ≤17.5 between BMD measurements lost 5.5-7.1% of the BMD at the hip (p<0.05). CONCLUSION: Young women with AN have 15% lower bone mass than healthy young women. The relationship between BMD and body weight seems to be a continuum across disease states. Increased body weight may be the most important factor for recovery of bone mass in AN patients.

Encapsulating peritoneal sclerosis following a peritoneal foreign body reaction to Dacron fibres-a case report.

The aetiological factors and the pathophysiological mechanisms of encapsulating peritoneal sclerosis (EPS) have not been fully elucidated. We present a patient on continuous ambulatory peritoneal dialysis whose peritoneal catheter was exchanged due to repeated episodes of bacterial peritonitis. Immediately afterwards, he experienced severe abdominal pain, nausea and fever. Peritoneal biopsy, taken 12 days after the operation, revealed fibrotic thickening of the peritoneum and a foreign body inflammatory reaction to particles manifesting striking similarity to the Dacron fibres of the catheter cuff. Shedding of Dacron fibres into the peritoneum may have elicited the acute fulminant phase of the EPS diagnosed in this case.

[In-hospital cardiopulmonary resuscitation at Landspitali University Hospital in Reykjavik]. / Imflang og árangur endurlífgunarstarfsemi á Landspítala.

INTRODUCTION: Survival after in-hospital cardiac arrest has not been previously reported in Iceland and the purpose of this study was to examine the outcomes of in-hospital resuscitation over a two year period. MATERIAL AND METHODS: There are resuscitation teams on each of the two campuses of the University Hospital in Reykjavik. Since the beginning of 2006, the resuscitation teams have compiled their reports in a structured form, Utstein style. RESULTS: During 2006 and 2007 resuscitation teams were activated on a total of 311 occasions. Of those, there was need for a full cardiopulmonary resuscitation because of cardiac arrest of in patients in 80 cases (26%). Return of spontaneous circulation was achieved or the patient survived to be transferred to the intensive care unit in 55 (69%) of the 80 cases. Survival to discharge was 33%. Survival to discharge was better if the arrest occurred between 8 AM and 4 PM during daytime (50%), than outside of regular working hours (23%, p=0.02). The survival was better if ventricular tachycardia or fibrillation was the first rhythm encountered (50%) than if the initial rhythm turned out to be asystole or pulseless electrical activity (12%, p=0.002). Those who survived resuscitation were generally younger than those who did not (p=0.002). CONCLUSION: The outcomes were similar to those reported at institutions in our neighboring countries. The survival rate was lower if the cardiac arrest occurred outside of regular working hours and if ventricular tachycardia or fibrillation was the first encountered rhythm.

[Encapsulating peritoneal sclerosis]. / Umlykjandi lífhimnuhersli--tvö tilfelli og yfirlit yfir sjúkdóminn.

The incidence of encapsulating peritoneal sclerosis in patients on peritoneal dialysis seems to be increasing worldwide. In Iceland, two cases of encapsulating peritoneal sclerosis have recently been diagnosed (cumulative incidence 1.6%). The patients followed a similar course; the disease was diagnosed in the wake of a bacterial peritonitis, steroid treatment was effective during the acute phase but eventually surgical treatment was needed and a successful enterolysis performed.

[Advances in detection, evaluation and management of chronic kidney disease]. / Langvinnur nýrnasjúkdómur--nýjar áherslur í greiningu og medferd.

The incidence of end-stage kidney failure has increased dramatically world-wide in recent decades. It is a disorder that carries high mortality and morbidity and its treatment is expensive. Increased emphasis has been placed on early detection in recent years in the hope that it may lead to preventive strategies. However, these efforts have been hampered by ambiguous disease definitions. Recent guidelines have defined chronic kidney disease (CKD) as glomerular filtration rate (GFR) less than 60 ml/min/1.73 m(2) and/or evidence of kidney damage by laboratory or imaging studies, of more than 3 months duration. Chronic kidney disease is divided into 5 stages based on renal function, where stage 1 is defined as normal GFR or above 90 ml/min/1.73 m(2), and stage 5 as GFR below 15 ml/min/1.73 m(2) which is consistent with end-stage kidney failure. The GFR can be measured directly but more conveniently it is calculated based on serum creatinine using formulas that have been shown to be fairly accurate. Epidemiological studies employing the new definition have shown that the prevalence of CKD is 5-10% in Western countries, leading to its recognition as a major public health problem. It has also been demonstrated that CKD is associated with increased cardiovascular risk. This year the Clinical Biochemistry Laboratory at Landspitali University Hospital will begin reporting the estimated GFR along with the serum creatinine values. It is important that Icelandic physicians learn to use the estimated GFR in their daily practice to make the diagnosis and staging of CKD more effective. Hopefully this will lead to earlier detection and institution of therapy that may retard the development of end-stage kidney failure and decrease the associated cardiovascular risk.

[Prevalence of secondary hyperparathyroidism (SHPT) and causal factors in adult population in Reykjavík area]. / Algengi og orsakir afleidds kalkvakaóhófs medal fullordinna á höfudborgarsvaedinu.

INTRODUCTION: SHPT is a consequence of decreased concentration of ionized calcium in blood, which may have many causes. The purpose of this study was to assess the prevalence and contributing factors of SHPT in an adult Icelandic population and explore the relationship between PTH and other variables which might explain age related increase in PTH. Such knowledge might be helpful in evaluating the results of PTH measurements. METHODS AND STUDY GROUP: The study group was a random sample of men and women in the Reykjavik area, 30-85 years of age. Serum PTH was measured by ECLIA (Roche Diagnostics), serum 25(OH)D by RIA (DiaSorin), and body composition by DXA. SHPT was defined as PTH >65 ng/l and ionized calcium <1.25 mmol/l. Inadequate vitamin D was defined as serum 25(OH)D 25-45 nmol/l and vitamin D deficiency <25 nmol/l, inadequate calcium intake <800 mg/day (from questionnaire) and reduced kidney function as serum cystatin-C >1.55 ng/l. The relationship between PTH and other variables was assessed by Spearman?s correlation coefficient and linear regression. RESULTS: Of 2,310 individuals invited 1,630 attended (70%), 586 men and 1,023 women. Further 21 were excluded because of primary hyperparathyroidism. Of the total group 6.6% did have SHPT, 7.7% of the women and 4.6% of men (p<0.01 by gender). Underlying causes were identified in 90% of cases, most commonly inadequate vitamin D (73%). Other important causes were obesity, inadequate calcium intake, reduced kidney function and furosemide intake. Many individuals did have more than one possible underlying cause. The concentration of PTH was found in a multivariate linear regression to be associated with age, ionized calcium, 25(OH)D, cystatin-C, smoking, and BMI, especially fat mass. Testosterone did have a weak negative relationship with PTH in men. CONCLUSIONS: Most cases of SHPT could be explained by known causes and far the commonest was inadequate vitamin D. The prevalence of SHPT in Iceland is probably higher than described elsewhere, possibly due to less sunlight exposure. These results would suggest that a greater intake of vitamin D is needed in Iceland. The relationship of PTH with body composition, especially fat mass, sex hormones and smoking, needs further evaluation.

[The role of omega-3 polyunsaturated fatty acids in clinical medicine.].

In recent years there has been a growing interest in the use of omega-3 polyunsaturated fatty acids as medical therapeutic agents, and a multitude of epidemiological and clinical studies have evaluated their role in health and disease. A drug containing high concentration of omega-3 polyunsaturated fatty acids has been approved for the treatment of hypertriglyceridemia and following myocardial infarction in some European countries. Furthermore, there is a growing body of evidence suggesting that these fatty acids may be of benefit in several other diseases. To date, the majority of research has focused on cardiovascular diseases including hypertension, atherosclerosis and the prevention of sudden cardiac death, where these fatty acids may be useful. In addition, several studies have suggested a beneficial effect in severe acute and chronic inflammatory diseases, particularly rheumatoid arthritis and immunoglobulin A nephropathy, although the results have not been consistent. Finally, the role of omega-3 polyunsaturated fatty acids in the structure and function of nervous tissue has prompted investigations on their effect on neurological development of premature and young infants and their use as therapeutic agents in psychiatric disorders. In this article we review the scientific evidence for the role of omega-3 polyunsaturated fatty acids in clinical medicine.

[Assessment of age-related changes in parathyroid hormone levels by different methods.].

BACKGROUND: Current assays measuring intact PTH may not only measure the active form, PTH(1-84), but also some large breakdown products, including PTH(7-84). A new method is believed to measure only PTH(1-84). The purpose of this study was to examine whether increases in intact PTH that accompany age, weight and worsening renal function could be related to breakdown products interfering with traditional assays. METHODS: We used data from an ongoing cross-sectional study on bone health in 40-85 years old Icelanders. Over a 12 month period, 1096 subjects were invited for a DEXA scan, blood test, height and weight measurements and each subject answered a questionnaire on health and medication. For the current analysis we excluded those who were taking medications affecting bone and mineral metabolism. PTH was measured using PTH elecsys (Roche) and the new PTH cap (Scantibodies). We used kappa statistic to assess agreement with regard to levels above upper reference values for each assay and ANOVA, Pearson's and Spearman's correlation coefficients for other analysis. Women and men were analyzed separately. RESULTS: Of 746 individuals who came for the study, after exclusion, 247 women and 209 men remained for this analysis. PTH was on the average roughly 40% lower with the new PTH cap assay. The correlation between the assays was 0.787 (P<0.001) for women and 0.69 (P<0.001) for men. Kappa statistic was 0.486 (P<0.001) for women and 0.283 (P<0.001) for men, indicating fair to good agreement. PTH elecsys increased with age (P=0.03 and P=0.01 for women and men, respectively) but not PTH cap (P=0.7 and P=0.09 for women and men, respectively). PTH elecsys was positively associated with cystatin C (P<0.05 for both genders), but the correlation between PTH cap and Cystatin C was not statistically significant. The association with body mass index was similar for the two assays (r=0.16 to 0.24, P<0.05) for both genders. CONCLUSIONS: There is a significant difference between these two PTH assays. It is likely that increases in intact PTH observed with age and worsening renal function are related to large breakdown products of PTH whereas the PTH increase seen with higher weight seems to be related to PTH(1-84) itself.

[Vitamin-D homeostasis amongst adult Icelandic population.].

BACKGROUND: The purpose of this study was to examine the effect of vitamin D intake and production in skin on vitamin D homeostasis in adult Icelanders. METHODS: Participants were 30-85 years old, randomly selected from the registry of the Reykjavik area (64 degrees N) and answered a thorough questionnaire on diet and vitamin supplements. Concentrations of 25(OH)-vitamin D [25(OH)D] in peripheral blood were examined based on season during the study period February 2001-January 2003, vitamin D intake and age (age groups 30-45, 50-65, and 70-85 years old). We defined vitamin D deficiency as either [25(OH)D] <25 nmol/l or as [25(OH)D] where the inverse relationship between serum iPTH and [25(OH)D] became statistically significant. RESULTS: Of 2310 invited, 1630 subjects participated (70,6% participation) but 21 individuals were excluded due to primary hyperparathyroidism. Mean [25(OH)D] was 46.5-/+20 nmol/l but varied by season, age and vitamin D intake, highest in June-July, 52.1-/+19.8 and lowest in February-March, 42.0-/+20.5 (p<0.001). [25(OH)D] was highest in the oldest age group, 50.8-/+19.7, but lowest in the youngest, 42.5-/+20 as was the intake 16.6-/+10 microg/day compared to 9.9-/+9 microg/day in the youngest. The correlation between vitamin D intake and [25(OH)D] was highest for the oldest group, r=0.41, p<0.001 but lowest in the youngest, r=0.24, p<0.001. [25(OH)D] was significantly higher among users of vitamin supplements (45.4-/+19.7) or fish oil (53.0-/+18.4) than among non-users (38.0-/+18.9). Vitamin D insufficiency was seen among 14.5% of those participating according to traditional definition, but 50% were below [25(OH)D] of 45 nmol/l where negative correlation between [25(OH)D] and PTH became statistically significant. CONCLUSIONS: The serum concentration of 25(OH)D at which vitamin D deficiency becomes biochemically significant is higher than traditionally thought. A daily intake of 15-20 microg/day during wintertime would be required to maintain normal homeostasis in Icelandic adults, which is considerably higher than present recommendations of 7-10 microg/day for adults. Further research is needed to define the limit for vitamin-D sufficiency.

[The relationship between physical activity, body mass index, body composition and grip strength in an Icelandic population.].

OBJECTIVE: To study physical activity among Icelandic adults and the relationship with anthropometric factors and grip strength. MATERIAL AND METHODS: Randomly selected participants, 30-85 years of age, answered questions regarding exercise and diet. Body composition was measured with DXA, which detects the proportions of different body tissues. Height, weight and grip strength were measured and the body mass index (kg/m(2)) was calculated. The prevalence of regular physical activity was studied for men and women in the age groups of 30-45 years, 50-65 years and 70-85 years and the relationship to body mass index, body composition and grip strength examined. The possible preventive effect of exercise on overweight and obesity was also studied. RESULTS: Of 2310 invited, 1630 subjects (70.6%) participated. Mean participation in regular physical activity was 3-4 times a week but 19% of the women and 24% of the men did no exercise at all. In general, swimming, walking and calisthenics of various types and intensities were the most common forms of exercise and in the age group 30-45 year old 16% of the women and 8% of the men did strength training. 50.4% of women 30-45 years of age and 68.2% of 50-65 year old men were overweight or obese. Mean fat mass was highest in 70-85 year old women (38%) and men (27%). Occupational activity was not related to body mass index, body composition or grip strength. Significant negative relationship was found between frequency of exercise and fat mass. The relationship between grip strength and lean mass or exercise was non-significant. The odds ratio of being overweight or obesity was 0.5 (CI was 0.37-0.77 for women and 0.37-0.94 for men) for those who exercised five or more days per week compared to those who exercised less frequently. CONCLUSION: One of four Icelandic men and one of five women do not participate in regular physical activity despite of strong scientific indications of various positive health effects of exercise. More than half of adult Icelanders are overweight or obese but the risk is halved among those who exercise at least five days per week, compared to those who exercise less frequently. Sedentary lifestyle is more common amongst Icelanders than in the neighboring countries and realistic goals need to be set to increase the participation in regular physical activity.