Chlamydia pneumoniae, heat shock proteins 60 and risk of secondary cardiovascular events in patients with coronary heart disease under special consideration of diabetes: a prospective study

BACKGROUND: There have been suggestions of an association between Chlamydia pneumoniae, chlamydial heat shock protein (Ch-hsp) 60 and human heat shock protein (h-hsp) 60 infection sero-status and development of secondary cardiovascular events. Patients with diabetes might be at higher risk since they are prone to infections. The objective of this study was to investigate prospectively the role of Chlamydia pneumoniae (CP), chlamydial heat shock protein (Ch-hsp) 60 and a possible intermediate role of human heat shock protein (h-hsp) 60 sero-status in the development of secondary cardiovascular disease (CVD) events in patients with coronary heart disease (CHD) under special consideration of diabetes mellitus. METHODS: Patients aged 30–70 undergoing an in-patient rehabilitation program after acute manifestation of coronary heart disease (International Classification of Disease, 9(th )Rev. pos. 410–414) between January 1999 and May 2000 in one of two participating rehabilitation clinics in Germany were included in this analysis. Chlamydia pneumoniae (CP), chlamydial heat shock protein (Ch-hsp) 60 and human heat shock protein (h-hsp) 60 status at baseline were measured by serum immunoglobulin G and A antibodies. Secondary CVD events (myocardial infarction, stroke, and cardiovascular death) were recorded during a mean follow-up period of 33.5 months (response = 87%). RESULTS: Among the 1052 subjects 37.4% and 39.3% were sero-positive to CP IgA and IgG respectively, 22.2% were sero-positive to Ch-hsp 60 IgG and 8.4% were positive to h-hsp 60 IgG at baseline. During follow-up, secondary CVD events occurred among 71 (6.8%) participants. Occurrence of a secondary CVD event was more common among CP (IgA) and CP (IgG) sero-positive than among sero-negative patients (p-values 0.04 and 0.1, respectively). The risk of secondary CVD events was increased among patients with both a positive CP sero-status and diabetes compared to infection negative, non-diabetic patients and in general, sero-positivity added a hazard to diabetes. The interaction term between infection sero-status and diabetes was not statistically significant. We were not able to show an intermediate role of human heat shock protein (h-hsp) 60 sero-status in the development of secondary CVD events in patients with CHD. CONCLUSION: Results from this cohort of 1052 patients with pre-existing CHD cannot exclude a possible moderate increase in risk of secondary CVD events among patients with a positive infection sero-status. However, our study showed no intermediate role of human heat shock protein (h-hsp) 60 sero-status in the development of secondary CVD events in patients with CHD. Larger studies or meta-analysis of multiple studies are needed to address the interaction between infection sero-status and diabetes with adequate power

Meta-analytische Verfahren zur Auswertung gemeindebezogener Interventionsstudien am Beispiel der deutschen Herz-Kreislauf-Präventionsstudie

Twardella D. Meta-analytische Verfahren zur Auswertung gemeindebezogener Interventionsstudien am Beispiel der deutschen Herz-Kreislauf-Präventionsstudie. Bielefeld (Germany): Bielefeld University; 2002.Bei der statistischen Analyse gemeindebezogener Interventionsstudien muss bedacht werden, dass Korrelationen zwischen Beobachtungen aus einer Gemeinde bestehen. In der vorliegenden Arbeit wird untersucht, inwieweit sich die statistischen Methoden der Meta-Analyse auf solche Studien übertragen lassen, Methoden, in denen Heterogenität, die Kehrseite der Korrelation, berücksichtigt werden. Am Beispiel der Deutschen Herz-Kreislauf-Präventionsstudie wird gezeigt, dass die Berücksichtigung der Heterogenität in der random effects Meta-Analyse zu vergleichbarer Varianzschätzung führt wie die Berücksichtigung der Korrelation im gemischten Modell, ein für solche Studien anerkanntes statistisches Verfahren. Die Vergrößerung der Varianz durch Berücksichtigung der Korrelation bzw. Heterogenität ist so stark, dass der in der fixed effects Analyse fälschlicherweise als statistisch signifikant erscheinende Effekt auf systolischen Blutdruck in der random effects Analyse nicht signifikant ist

Relationship between noise annoyance from road traffic noise and cardiovascular diseases: A meta-analysis

Road traffic noise is an important source of noise annoyance in the community. We performed a meta-analysis to assess whether there is an association between noise annoyance from road traffic noise and cardiovascular diseases (arterial hypertension and ischemic heart disease) in adult population. The meta-analysis included studies that: a. had noise annoyance as exposure, quantified either as "annoyed versus non-annoyed" or with various scales collected by standardized questionnaires; b. arterial hypertension or ischemic heart disease as outcome; c. had included only adult population (age >18 years); d. the studies had to have as effect size odds ratios or relative risk. From the individual studies those odds ratios were selected for meta-analysis which compared most distant categories. Eight studies that fulfilled criteria published between 1992 and 2006 were included in the meta-analysis: 6 studies had a cross-sectional design, 1 study had a case-control-design and 1 study had a cohort design. Increased annoyance was significantly associated with arterial hypertension (pooled risk estimate = 1.16, 95% confidence interval 1.02-1.29) while the association with ischemic heart disease did not reach statistical significance (pooled risk estimate = 1.07, 95% confidence interval 0.99-1.14). No publication bias was evidenced. The results of this meta-analysis demonstrated the existence of a positive and significant association between noise annoyance from road traffic and the risk of arterial hypertension and a positive yet insignificant association between noise annoyance and the risk of ischemic heart disease

Usage of personal music players in adolescents and its association with noise-induced hearing loss: A cross-sectional analysis of Ohrkan cohort study data

Objective: To describe personal music player (PMP) usage among adolescents, sociodemographic determinants and association with audiometric notches. Design: Audiometric evaluation to assess hearing status, and standardized questionnaires to evaluate PMP listening behaviors, leisure noise exposures and self-reported hearing loss symptoms. Sociodemographic information was collected using a parent questionnaire. Noise exposure by PMP usage equivalent for a 40h week was estimated based on self-reported volume and duration of use. Study sample: A total of 2143 students (54% females) attending 9th grade in Regensburg, Germany, during 2009 to 2011. Results: Overall, 85% of the students reported using PMPs. Exposure level exceeded 80dB(A) in approximately one third, and 85dB(A) in one quarter, of those who used PMP. An audiometric notch was found in 2.3% of participants, but was not significantly associated with higher PMP exposure. Conclusions: PMP exposure above the occupational limits of 80 and 85dB(A) set by the Directive 2003/10/EC may be a risk factor for developing noise-induced hearing loss. Educational measures to ameliorate high risk behaviors in PMP usage are needed, particularly for socially disadvantaged groups

The prevalence of audiometric notches in adolescents in Germany: The Ohrkan-study

Although there is concern about increasing hearing loss in adolescents caused by leisure noise exposure, prevalence data are scarce. In an US study, about 16-17% of adolescents were affected by audiometric notches. To estimate the prevalence of audiometric notches in adolescents in Germany, baseline data of the cohort study Ohrkan, recruitment during the school years 2009/2010 and 2010/2011 were analyzed. All students in grade 9 visiting any school in the city of Regensburg were eligible for participation. Data was collected via standardized questionnaires from students and their parents. In addition, students were asked to visit the University Clinics of Regensburg for ear examination including a tympanogram and the determination of hearing thresholds in air conduction audiometry. The prevalence of audiometric notches was determined in students with normal tympanogram in both ears and complete audiometry data. Audiometric notches were defined according to criteria used to analyse US data. Overall, 2149 students (1158 girls, 991 boys mainly aged 15-16 years) of the 3846 eligible adolescents (56%) participated. Among the 1843 adolescents with complete audiometry and tympanometry data, the prevalence of audiometric notches was 2.4% (95% confidence interval 1.7-3.1%). We could not confirm the high prevalence of audiometric notches as reported in National Health and Nutrition Examination Surveys for adolescents in the US. Differences in prevalence might be at least partly due to methodical differences in audiometry. Even if empirical evidence is presently ambiguous, it is reasonable to educate young people about the potential risks of high leisure noise exposure