Søren Lundbye-Christensen

Validity of the diagnoses atrial fibrillation and atrial flutter in a Danish patient registry

Objectives. To assess the validity of the diagnoses of atrial fibrillation (AF) and atrial flutter (AFL) for men and women recorded in the Danish National Patient Registry, and to assess the relative distribution of AF and AFL. Design. Review of medical records for incident cases of AF and/or AFL in the Diet, Cancer, and Health cohort study. Participants were enrolled in 1993–97 with 13.6 years of follow-up until 30 December, 2009. Results. The positive predictive value of the combined diagnosis of AF and/or AFL was 92.6% (95% CI 88.8%; 95.2%) with no significant difference between sexes (men 93.7% (133/142), women 90.8% (129/142)). The proportion of AFL either alone or in combination with AF was significantly higher in men than in women (13.5% (18/133) vs. 5.4% (7/129), p =0.03). The positive predictive value of the specified diagnosis of AFL was 57.5% for men (46/80) and 29.6% for women (8/27). Conclusions. This study shows that the validity of the diagnosis of AF and/or AFL is high and may be used for registry-based studies. A specified diagnosis of AFL was rarely used and was not reliable to distinguish between cases of AF and AFL.

Longitudinal MRI study of cortical thickness, perfusion, and metabolite levels in major depressive disorder

Järnum H, Eskildsen SF, Steffensen EG, Lundbye‐Christensen S, Simonsen CW, Thomsen IS, Fründ E‐T, Théberge J, Larsson E‐M. Longitudinal MRI study of cortical thickness, perfusion, and metabolite levels in major depressive disorder.

High prevalence of foot problems in the Danish population: A survey of causes and associations

OBJECTIVE To determine the prevalence and severity of foot pain and deformity and the associated risk of leg and low back pain. METHOD A cross-sectional postal survey was conducted among a randomly selected sample of 2100 adult Danish inhabitants (18-80 years of age). Participants reported 1-month period prevalences of foot, lower leg, knee, hip and back pain. RESULTS Responder rate was 79.6%. Prevalence of foot pain was 30.4% with a total of 55.9% reporting pain in the foot, leg or back lasting more than 1 day within the previous month. Foot pain lasting more than 1 month was experienced by 16.2% and 11.9% had pain lasting more than 1 year. The prevalence of self-reported pes planus or pes cavus was 17.9%. There was a significant association between foot pain and pain elsewhere in the leg and low back. Self-reported foot deformity was significantly associated with foot pain. Women had a significantly higher prevalence of foot pain and Body Mass Index was associated with foot pain in women but not in men. CONCLUSIONS Foot pain is highly prevalent and associated with foot deformity and leg and low back pain. More attention should be focused on foot pain and foot deformity. It is suggested that clinical examination of leg and low back pain should include foot examination.

Preoperative plasma D-dimer is a predictor of postoperative deep venous thrombosis in colorectal cancer patients: a clinical, prospective cohort study with one-year follow-up

PURPOSE: The study examined if preoperative plasma D-dimer level was associated with the postoperative cumulative incidence of deep venous thrombosis in patients with colorectal cancer admitted for intended curative surgery. METHODS: In 176 consecutive patients with newly-diagnosed colorectal cancer and absence of preoperative deep venous thrombosis, we measured the preoperative plasma D-dimer levels and performed compression ultrasonography for deep venous thrombosis prior to surgery, as well as one week, one month, and one year after surgery. RESULTS: The cumulative incidence of deep venous thrombosis up to one year after surgery was 20 percent (95 percent confidence interval, 12 to 31 percent) in the positive D-dimer group compared with 5 percent (95 percent confidence interval, 2 to 12 percent) in the negative D-dimer group. The adjusted hazard ratio of deep venous thrombosis in the positive vs. the negative D-dimer group was 6.53 (95 percent confidence interval, 1.58 to 27.0). CONCLUSIONS: A positive preoperative D-dimer was associated with a higher cumulated incidence of postoperative deep venous thrombosis. D-dimer might be useful in identifying those colorectal cancer patients who fail to respond to standard prophylaxis for deep venous thrombosis.

The North Jutland County Diabetic Retinopathy Study. Population characteristics

Background: Several population-based studies have reported blood glucose levels and blood pressure to be risk factors for the development of diabetic retinopathy. These studies were initiated more than two decades ago and may therefore reflect the treatment and population composition of a previous era, suggesting new studies of the present population with diabetes. Aim and methods: This cross-section study included 656 people with type 1 diabetes and 328 with type 2 diabetes. Crude prevalence rates of proliferative diabetic retinopathy, clinically significant macular oedema and several specific retinal lesions were assessed, together with their association to a simplified and internationally approved retinal grading. Results: The point prevalence of proliferative retinopathy was found to be 0.8% and 0.3% for type 1 and type 2 diabetes. Equivalent prevalence rates of clinically significant macular oedema were 7.9% and 12.8%, respectively. The most frequently occurring retinal manifestations increased in number until retinopathy level 3, and then decreased. Conclusion: The point prevalence of proliferative retinopathy is lower than that found in previous studies, whereas it is increased for clinically significant macular oedema. These data suggest different risk factors for these clinical entities.

Low-dose fish oil supplementation increases serum adiponectin without affecting inflammatory markers in overweight subjects

Obesity is associated with an increased risk of cardiovascular disease, whereas long-chain n-3 polyunsaturated fatty acids (PUFAs) from fish may have cardioprotective and anti-inflammatory effects. This study aimed to investigate the hypothesis that acute and short-term supplementation with a low dose of marine n-3 PUFA exerts an anti-inflammatory effect in overweight subjects. In a double-blind, placebo-controlled trial with 2 parallel groups, 50 overweight subjects were randomized to receive daily supplementation with 2 capsules containing either 2 g of fish oil (1.1 g marine n-3 PUFA) or 2 g of olive oil. Blood samples and adipose tissue biopsies were collected at baseline, after 1 day (acute effect), and after 6 weeks (short-term effect) of supplementation. No significant effects were seen after supplementation for 1 day, but after 6 weeks, subjects receiving fish oil had a significant increase in the n-3 PUFA content of granulocytes and adipose tissue (P < .01). Serum adiponectin levels were increased by 0.55 μg/mL (95% confidence interval, 0.02-1.08) in the fish oil group compared with the control group (P = .04) after 6 weeks of supplementation. Levels of interleukin 6 were inversely correlated to the marine n-3 PUFA content of granulocytes and adipose tissue at baseline (excluding α-linolenic acid). In conclusion, daily supplementation with 1.1 g of marine n-3 PUFA significantly increased serum adiponectin, but the effect was small, and no overall anti-inflammatory effect of the supplement could be demonstrated.

A 20-year ecological study of the temporal association between influenza and meningococcal disease

Both influenza and meningococcal disease (MD) show seasonal variation with peak incidence rates during the winter. We examined whether fluctuations in occurrence of influenza were associated with changes in the incidence rate of MD, either simultaneously or with a delay of one or 2 weeks, and whether age had an impact on these associations. This ecological study was based on weekly surveillance data on influenza and a complete registration of MD cases (n = 413) in North Jutland County, Denmark, during 1980–1999. A total of 379 MD cases occurred during weeks with influenza registration. The analysis was done using a Poisson regression model taking into account the seasonal variation and trend over time in incidence rate of MD, and stratified by age: <1 year (n = 38), 1–14 years (n = 189), and ≥ 14 years (n = 152). An increase of 100 registered cases of influenza per 100,000 inhabitants was associated with a 7% (95% CI: −1 to 15%) increase in the number of MD cases during the same week. The association was most marked for <1 year-olds, corresponding to a 29% (95% CI: 6–58%) increase in the number of MD cases per 100 cases of influenza per 100,000 inhabitants. Our findings support the theory that the influenza detection rate is associated with the number of MD cases in the population during the same week.

Promoter polymorphisms in the chitinase 3-like 1 gene influence the serum concentration of YKL-40 in Danish patients with rheumatoid arthritis and in healthy subjects

IntroductionThe present study investigates the association between single nucleotide polymorphisms (SNPs) in the chitinase 3-like 1 (CHI3L1) gene and serum concentrations of YKL-40 in Danish patients with rheumatoid arthritis (RA) and healthy controls as well as the association with RA in the Danish population. The CHI3L1 gene is located on chromosome 1q32.1 and encodes the YKL-40 glycoprotein. YKL-40 concentrations are elevated in the serum of patients with RA compared to healthy subjects, and YKL-40 has been suggested to be an auto-antigen and may play a role in development of RA and in inflammation.MethodsEight SNPs in the CHI3L1 gene and promotor were genotyped in 308 patients with RA and 605 controls (healthy blood donors) using TaqMan allele discrimination assays. Serum concentrations of YKL-40 were determined by an enzyme-linked immunosorbent assay (ELISA).ResultsWe found significant association between the serum concentrations of YKL-40 and polymorphism in the CHI3L1 gene among both patients with RA and controls. The g.-131(C > G) polymorphism (rs4950928) was most strongly associated with age adjusted serum concentrations of YKL-40 in patients with RA (P < 2.4e-8) and controls (P < 2.2e-16). No significant allelic- or genotypic association with RA was found in this Danish cohort.ConclusionsWe suggest that the g.-131(C > G) promoter polymorphism has a substantial impact on serum concentrations of YKL-40 in patients with RA and healthy subjects. However, the polymorphism does not seem to confer risk to RA itself. The effect of CHI3L1 polymorphism on clinical outcome or the response to treatment in patients with RA remains to be investigated.

Parity and risk of diabetes in a Danish nationwide birth cohort

Diabet. Med. 28, 43–47 (2011)

A longitudinal study of emergency room visits and air pollution for Prince George, British Columbia

A new method for regression analysis of longitudinal counts is applied to data from Prince George, British Columbia, previously analysed by Knight et al. The data consist of daily recordings of the number of emergency room visits for each of four categories of respiratory diseases, along with measurements of meteorological variables and air pollution. We use a state-space model assuming conditionally independent Poisson counts for the four categories given a latent morbidity process, the latent process being a gamma Markov process. The main objective of the investigation was to examine the relationship between air pollution and respiratory morbidity, taking into account seasonality and meteorological conditions. We found that total reduced sulphur significantly influences the expected number of emergency room visits for the four disease categories, in agreement with the conclusion by Knight et al. However, our final model is simpler than theirs; in particular we found no evidence of seasonal variation beyond that explained by the meteorological variables.