Residential radon and lung cancer incidence in a Danish cohort

High-level occupational radon exposure is an established risk factor for lung cancer. We assessed the long-term association between residential radon and lung cancer risk using a prospective Danish cohort using 57,053 persons recruited during 1993-1997. We followed each cohort member for cancer occurrence until 27 June 2006, identifying 589 lung cancer cases. We traced residential addresses from 1 January 1971 until 27 June 2006 and calculated radon at each of these addresses using information from central databases regarding geology and house construction. Cox proportional hazards models were used to estimate incidence rate ratios (IRR) and 95% confidence intervals (CI) for lung cancer risk associated with residential radon exposure with and without adjustment for sex, smoking variables, education, socio-economic status, occupation, body mass index, air pollution and consumption of fruit and alcohol. Potential effect modification by sex, traffic-related air pollution and environmental tobacco smoke was assessed. Median estimated radon was 35.8 Bq/m(3). The adjusted IRR for lung cancer was 1.04 (95% CI: 0.69-1.56) in association with a 100 Bq/m(3) higher radon concentration and 1.67 (95% CI: 0.69-4.04) among non-smokers. We found no evidence of effect modification. We find a positive association between radon and lung cancer risk consistent with previous studies but the role of chance cannot be excluded as these associations were not statistically significant. Our results provide valuable information at the low-level radon dose range.

Bacteremia with Streptococcus pneumoniae: sepsis and other risk factors for 30-day mortality--a hospital-based cohort study

We conducted a hospital-based cohort study among adult patients with first-time Streptococcus pneumoniae bacteremia (SPB) from 2000 through 2008. Patients were identified in a population-based bacteremia database and followed up for mortality through the Danish Civil Registration System (CRS). The aim of the study was to determine the focal diagnosis of SPB, the severity of sepsis at presentation, demographics and comorbidity characteristics of the patients, and to determine the 30-day mortality rate and factors related to mortality. We identified 481 patients, of which 238 were males. The mean age of the patients was 65 years. The focal diagnosis of the SPB was pneumonia in 381 (79 %) patients, followed in frequency by meningitis in 33 (7 %) patients. Of the 481 patients, 390 (81 %) had community-acquired SPB. Of these, 23 (6 %) did not have sepsis, 132 (34 %) had sepsis, 224 (57 %) had severe sepsis, and 11 (3 %) were in septic shock. Overall, the 30-day mortality was 16 %. Mortality increased with the severity of sepsis. There was no association between the focal diagnosis of SPB or the number of diagnoses and mortality. Nosocomial infection, male sex, increasing age, and increasing comorbidity were all associated with an increased 30-day mortality rate.

Major but differential decline in the incidence of Staphylococcus aureus bacteraemia in HIV-infected individuals from 1995 to 2007: a nationwide cohort study*

OBJECTIVES

Incidence rates (IRs) of Staphylococcus aureus bacteraemia (SAB) are known to be higher in HIV-infected individuals than in the general population, but have not been assessed in the era of highly active antiretroviral therapy.

METHODS

From 1 January 1995 to 31 December 2007, all Danish HIV-infected individuals (n=4871) and population controls (n=92 116) matched on age and sex were enrolled in a cohort and all cases of SAB were registered. IRs and risk factors were estimated using time-updated Poisson regression analysis.

RESULTS

We identified 329 cases of SAB in 284 individuals, of whom 132 individuals were infected with HIV and 152 were not [crude IR ratio (IRR) 24.2; 95% confidence interval (CI) 19.5-30.0, for HIV-infected vs. non-HIV-infected individuals]. Over time, IR declined for HIV-infected individuals (IRR 0.40). Injecting drug users (IDUs) had the highest incidence and the smallest decline in IR, while men who have sex with men (MSM) had the largest decline over time. Among HIV-infected individuals, a latest CD4 count <100 cells/μL was the strongest independent predictor of SAB (IRR 10.2). Additionally, HIV transmission group was associated with risk of SAB. MSM were more likely to have hospital-acquired SAB, a low CD4 cell count and AIDS at the time of HIV acquisition compared with IDUs.

CONCLUSIONS

We found that the incidence of SAB among HIV-infected individuals declined during the study period, but remained higher than that among HIV-uninfected individuals. There was an unevenly distributed burden of SAB among HIV transmission groups (IDU>MSM). Low CD4 cell count and IDU were strong predictors of SAB among HIV-infected individuals.

Hepatitis C treatment response kinetics and impact of baseline predictors

The optimal duration of treatment for hepatitis C virus (HCV) infections is highly variable but critical for achieving cure (sustained virological response, SVR). We prospectively investigated the impact of age, fibrosis, baseline viraemia and genotype on the early viral kinetics and treatment outcome. Patients treated with peginterferon alfa-2a and ribavirin in standard dosing were included: 49 with genotype 1 treated for 48weeks and 139 with genotype 2 or 3 treated for 24weeks. The reduced SVR rates in patients older than 45years, with severe liver fibrosis or pretreatment viraemia above 400,000IU/mL were strongly associated with slower second phase declines of HCV RNA. Genotype 2/3 infections responded more rapidly than genotype 1, reaching week 4 negativity (RVR) in 59%vs 22%. We conclude that baseline response predictors such as age, fibrosis and viral load were well reflected by the early viral kinetics as assessed by repeated HCV RNA quantifications. The kinetic patterns and the high relapse rate in genotype 2/3 patients without RVR suggest that this group might benefit from treatment durations longer than 24weeks.

Ribavirin plasma concentration is a predictor of sustained virological response in patients treated for chronic hepatitis C virus genotype 2/3 infection

In hepatitis C virus (HCV) genotype 1 infection, the likelihood of obtaining sustained virological response (SVR) is associated with higher ribavirin exposure. Such an association has not been demonstrated for HCV genotype 2/3 infection, where a fixed 800 mg daily dosing of ribavirin is generally recommended. The primary aim of this study was to investigate the correlation between ribavirin concentration at day 29 and therapeutic response in patients with HCV genotype 2/3 infection. A total of 382 patients were randomized to 12 or 24 weeks of treatment with pegylated interferon-alfa 2a 180 μg weekly and 800 mg ribavirin daily. Trough plasma concentration of ribavirin was measured at day 29 and week 12 and the primary outcome was SVR (HCV-RNA undetectable 24 weeks after treatment). Of the 382 patients, 355 had a ribavirin concentration available at day 29. SVR was 84% among patients with a ribavirin concentration ≥2 mg/L at day 29 compared to 66% in those with concentrations <2 mg/L (P = 0.002). The corresponding figures in the 12-week treatment group were 74% and 57% (P = 0.12), and in the 24-week treatment group 91% and 75% (P = 0.02), respectively. In a multivariate analysis, ribavirin concentration at day 29 was an independent predictor of SVR (P = 0.002). In conclusion, a higher plasma ribavirin concentration is associated with an increased likelihood of achieving SVR in HCV genotype 2/3 infection. Individualization of ribavirin dosing may be helpful in improving outcome, especially in the presence of unfavourable baseline characteristics. This, however, requires evaluation in a prospective trial.

Previously unrecognized advanced liver disease unveiled by transient elastography in patients with Haemophilia and chronic hepatitis C

Before the introduction of viral inactivation procedures and viral screening of plasma-products, haemophiliacs were at high risk of infection with HCV. Those who acquired HCV infection in the 1980s, and are still alive today, may have developed significant liver fibrosis or cirrhosis. However, liver biopsy has not routinely been utilized in the evaluation of haemophiliacs with HCV in Denmark. The aim of this study was to investigate the prevalence of significant fibrosis/cirrhosis among haemophiliacs as evaluated by transient elastography (TE). Cross-sectional investigation of adult patients with haemophilia A or B. TE with liver stiffness measurements (LSM) ≥ 8 kPa were repeated after 4-6 weeks. Significant fibrosis and cirrhosis was defined as measurements ≥ 8 kPa or ≥ 12 kPa respectively. Among 307 patients with haemophilia A or B registered at the two Haemophilia centres, 141(46%) participate in this study. Forty (28.4%) had chronic hepatitis C, 33 (23.4%) past hepatitis C and 68 (48.2%) had never been infected, at screening LSM ≥ 8 kPa were found in 45.7%, 24.7% and 4.6% respectively. Among patients with chronic hepatitis C significant fibrosis was confirmed in 17.1% and cirrhosis in 2.9% by repeated LSM ≥ 8 and ≥ 12 kPa respectively. The median TE-value in never HCV-infected haemophiliacs was comparable with what has been found in healthy non-haemophiliacs. In Danish haemophiliacs where liver biopsy has not routinely been used for assessing severity of liver fibrosis, LSM identified advanced liver disease in one-fifth of cases that had not been recognized during clinical follow-up.

Decline in hepatitis B infection observed after 11 years of regional vaccination among Danish drug users

The aims of this study were to determine the current prevalence of viral hepatitis and HIV among drug users, and to compare this prevalence with previous findings in the same geographical region. Cross-sectional surveys of drug users attending treatment centers on the island of Funen with approximately 500,000 inhabitants were administered in 1996 and 2007. The 2007 prevalence estimates were: anti-HBc 50.2%, HBsAg 0.9%, anti-HCV 66.8%, HCV-RNA 40%, and anti-HIV 1.1%. The corresponding 1996 prevalence values were: anti-HBc 70% (P < 0.0001), HBsAg 9.8% (P < 0.0001), anti-HCV 82.8% (P < 0.0001), HCV-RNA 56.3% (P = 0.002), and anti-HIV 1% (P = 1). The 2007 prevalence of viral hepatitis decreased due to the increasing proportion of non-injectors. Among injectors, the prevalence remained unchanged except for a significant decrease in HBsAg. The 2007 prevalence of ongoing HBV infection among infected (HBsAg/anti-HBc proportion) was the lowest that to our knowledge has been reported among drug-users. Vaccination coverage among susceptible persons tested in 2007 was 24%, compared to 0.7% in 1996. Therefore, despite an unchanged prevalence of anti-HBc among injecting drug users, a highly significant drop in HBsAg prevalence was seen during the last decade. This observation may be linked causally to an increase in hepatitis B vaccination of the susceptible population. Our findings suggest that even incomplete vaccination, without persistent protective anti-HBs levels, may induce an immune memory sufficient to prevent chronic infection upon transmission.

HIV and risk of venous thromboembolism: a Danish nationwide population-based cohort study

OBJECTIVE

The association between HIV infection and the risk of venous thromboembolism (VTE) is controversial. We examined the risk of VTE in HIV-infected individuals compared with the general population and estimated the impact of low CD4 cell count, highly active antiretroviral therapy (HAART) and injecting drug use (IDU).

METHODS

We identified 4333 Danish HIV-infected patients from the Danish HIV Cohort Study and a population-based age- and gender-matched comparison cohort of 43,330 individuals. VTE diagnoses were extracted from the Danish National Hospital Registry. Cumulative incidence curves were constructed for time to first VTE. Incidence rate ratios (IRRs) and impact of low CD4 cell count and HAART were estimated by Cox regression analyses. Analyses were stratified by IDU, adjusted for comorbidity and disaggregated by overall, provoked and unprovoked VTE.

RESULTS

The 5-year risk of VTE was 8.0% [95% confidence interval (CI) 5.78-10.74%] in IDU HIV-infected patients, 1.5% (95% CI 1.14-1.95%) in non-IDU HIV-infected patients and 0.3% (95% CI 0.29-0.41%) in the population comparison cohort. In non-IDU HIV-infected patients, adjusted IRRs for unprovoked and provoked VTE were 3.42 (95% CI 2.58-4.54) and 5.51 (95% CI 3.29-9.23), respectively, compared with the population comparison cohort. In IDU HIV-infected patients, the adjusted IRRs were 12.66 (95% CI 6.03-26.59) for unprovoked VTE and 9.38 (95% CI 1.61-54.50) for provoked VTE. Low CD4 cell count had a minor impact on these risk estimates, while HAART increased the overall risk (IRR 1.93; 95% CI 1.00-3.72).

CONCLUSION

HIV-infected patients are at increased risk of VTE, especially in the IDU population. HAART and possibly low CD4 cell count further increase the risk.

Bone mineral density changes in protease inhibitor-sparing vs. nucleoside reverse transcriptase inhibitor-sparing highly active antiretroviral therapy: data from a randomized trial

OBJECTIVE

The aim of the study was to compare changes in bone mineral density (BMD) over 144 weeks in HIV-infected patients initiating nucleoside reverse transcriptase inhibitor (NRTI)-sparing or protease inhibitor-sparing highly active antiretroviral therapy (HAART).

METHODS

Sixty-three HAART-naïve patients were randomized to zidovudine/lamivudine+efavirenz or lopinavir/ritonavir+efavirenz. We performed dual energy X-ray absorptiometry (DEXA) at baseline and at weeks 24, 48, 96 and 144 to evaluate lumbar spine and femoral neck (hip) BMD.

RESULTS

At baseline, 33 patients (55.9%) had low BMD (T-score < -1.0) and of these eight had osteoporosis (T-score < -2.5). Spine BMD declined in both arms until week 24, before stabilizing. In the NRTI-sparing arm, the mean percentage change from baseline was -2.7% [95% confidence interval (CI) -3.9 to -1.4] at week 24 and -2.5% (95% CI -5.4 to 0.3) at week 144, compared with -3.2% (95% CI -4.4 to -2.1) and -1.9% (95% CI -3.5 to -0.3) in the protease inhibitor-sparing arm. Hip BMD declined until week 48 before stabilizing. In the NRTI-sparing arm, BMD had decreased by -5.1% (95% CI -7.1 to -3.1) at week 48 and -4.5% (95% CI -6.9 to -2.1) at week 144, compared with -6.1% (95% CI -8.2 to -4.0) and -5.0% (95% CI -6.8 to -3.1) in the protease inhibitor-sparing arm. There were no significant differences between arms. Low baseline CD4 cell count was independently associated with spine (P=0.007) and hip (P=0.04) BMD loss and low body mass index with hip BMD loss (P=0.03).

CONCLUSION

Spine and hip BMD declined rapidly 24 to 48 weeks after initiating HAART, independent of the assigned drug class, but thereafter BMD values remained stable.

Defining occupational and consumer exposure limits for enzyme protein respiratory allergens under REACH

A wide range of substances have been recognized as sensitizing, either to the skin and/or to the respiratory tract. Many of these are useful materials, so to ensure that they can be used safely it is necessary to characterize the hazards and establish appropriate exposure limits. Under new EU legislation (REACH), there is a requirement to define a derived no effect level (DNEL). Where a DNEL cannot be established, e.g. for sensitizing substances, then a derived minimal effect level (DMEL) is recommended. For the bacterial and fungal enzymes which are well recognized respiratory sensitizers and have widespread use industrially as well as in a range of consumer products, a DMEL can be established by thorough retrospective review of occupational and consumer experience. In particular, setting the validated employee medical surveillance data against exposure records generated over an extended period of time is vital in informing the occupational DMEL. This experience shows that a long established limit of 60 ng/m(3) for pure enzyme protein has been a successful starting point for the definition of occupational health limits for sensitization in the detergent industry. Application to this of adjustment factors has limited sensitization induction, avoided any meaningful risk of the elicitation of symptoms with known enzymes and provided an appropriate level of security for new enzymes whose potency has not been fully characterized. For example, in the detergent industry, this has led to general use of occupational exposure limits 3-10 times lower than the 60 ng/m(3) starting point. In contrast, consumer exposure limits vary because the types of exposure themselves cover a wide range. The highest levels shown to be safe in use, 15 ng/m(3), are associated with laundry trigger sprays, but very much lower levels (e.g. 0.01 ng/m(3)) are commonly associated with other types of safe exposure. Consumer limits typically will lie between these values and depend on the actual exposure associated with product use.

[Personal health contact systems for cancer patients in Danish hospital wards]

INTRODUCTION

We examined personal health contact systems for cancer patients in Danish hospital wards and investigated whether there is a relation between patients' experience of having a personal health contact and the presence of a health contact system.

MATERIAL AND METHODS

The personal health contact systems were examined by means of a questionnaire survey. Data from the questionnaire were combined with data from an earlier questionnaire study on cancer patients' needs to examine the relation between patients' experience of having a personal health contact and the presence of a health contact system.

RESULTS

The majority of hospital wards included in the study had introduced a personal health contact system, but the time of implementation and specific organization of the systems vary. We found a statistically significant relation between the presence of personal health contact systems and patients' experience of having a personal health contact, but it was weak.

CONCLUSION

Although most hospital wards have introduced personal health contact systems, their actual impact has been limited.

Abacavir and risk of myocardial infarction in HIV-infected patients on highly active antiretroviral therapy: a population-based nationwide cohort study

OBJECTIVE

The aim of the study was to examine whether exposure to abacavir increases the risk for myocardial infarction (MI).

DESIGN, SETTING AND SUBJECTS

This was a prospective nationwide cohort study which included all Danish HIV-infected patients on highly active antiretroviral therapy (HAART) from 1995 to 2005 (N = 2952). Data on hospitalization for MI and comorbidity were obtained from Danish medical databases. Hospitalization rates for MI after HAART initiation were calculated for patients who used abacavir and those who did not. We used Cox's regression to compute incidence rate ratios (IRR) as a measure of relative risk for MI, while controlling for potential confounders (as separate variables and via propensity score) including comorbidity.

MAIN OUTCOME

Relative risk of hospitalization with MI in abacavir users compared with abacavir nonusers.

RESULTS

Hospitalization rates for MI were 2.4/1000 person-years (PYR) [95% confidence interval (CI) 1.7-3.4] for abacavir nonusers and 5.7/1000 PYR (95% CI 4.1-7.9) for abacavir users. The risk of MI increased after initiation of abacavir [unadjusted IRR = 2.22 (95% CI 1.31-3.76); IRR adjusted for confounders = 2.00 (95% CI 1.10-3.64); IRR adjusted for propensity score = 2.00 (95% CI 1.07-3.76)]. This effect was also observed among patients initiating abacavir within 2 years after the start of HAART and among patients who started abacavir as part of a triple nucleoside reverse transcriptase inhibitor (NRTI) regimen.

CONCLUSIONS

We confirmed the association between abacavir use and increased risk of MI. Further studies are needed to control for potential confounding not measured in research to date.

Evaluation of the furosine and homoarginine methods for determining reactive lysine in rumen-undegraded protein

Three samples of soybean meal (SBM), 3 samples of expeller SBM (SoyPlus, West Central Cooperative, Ralston, IA), 5 samples of distillers dried grains with solubles (DDGS), and 5 samples of fish meal were used to evaluate the furosine and homoarginine procedures to estimate reactive Lys in the rumen-undegraded protein fraction (RUP-Lys). One sample each of SBM, expeller SBM, and DDGS were subjected to additional heat treatment in the lab to ensure there was a wide range in reactive RUP-Lys content among the samples. Furosine is a secondary product of the initial stages of the Maillard reaction and can be used to calculate blocked Lys. Homoarginine is formed via the reaction of reactive Lys with O-methylisourea and can be used to calculate the concentration of reactive Lys. In previous experiments, each sample was ruminally incubated in situ for 16 h, and standardized RUP-Lys digestibility of the samples was determined in cecectomized roosters. All rumen-undegraded residue (RUR) samples were analyzed for furosine and Lys; however, only 9 of the 16 samples contained furosine, and only the 4 unheated DDGS samples contained appreciable amounts of furosine. Blocked RUP-Lys was calculated from the furosine and Lys concentrations of the RUR. Both the intact feed and RUR samples were evaluated using the homoarginine method. All samples were incubated with an O-methylisourea/BaOH solution for 72 h and analyzed for Lys and homoarginine concentrations. Reactive Lys concentrations of the intact feeds and RUR were calculated. Results of the experiment indicate that blocked RUP-Lys determined via the furosine method was negatively correlated with standardized RUP-Lys digestibility, and reactive RUP-Lys determined via the guanidination method was positively correlated with standardized RUP-Lys digestibility. Reactive Lys concentrations of the intact samples were also highly correlated with RUP-Lys digestibility. In conclusion, the furosine assay is useful in predicting RUP-Lys digestibility of DDGS samples, and the guanidination procedure can be used to predict RUP-Lys digestibility of SBM, expeller SBM, DDGS, and fish meal samples.

Neonatal stimulation of beta-cells reduces the incidence and delays the onset of diabetes in a barrier-protected breeding colony of BB rats

The off-spring in a barrier maintained colony of spontaneously type 1 diabetic BB/Wor/Mol-BB rats was treated with a daily injection of either saline, forskolin, arginine, glucose or both glucose and arginine for the first six days after birth. The incidence was reduced from 88% to 72% by the neonatal stimulation with arginine and glucose in combination, which also delayed the onset time from 76.0 +/- 2.2 days to 88.1 +/- 2.3 days. No such effect was observed after stimulation with either one of the compounds. Neonatal stimulation with forskolin also delayed the onset to 87.9 +/- 3.8 days, however without reducing the incidence. A higher incidence of diabetes was observed in the barrier-protected rats taking part in this study than in an earlier study using BB rats of the same origin, but kept under conventional conditions.