Objective Analysis of changes in leisure noise exposure among adolescents during 2.5 years of follow-up. Methods The analysis is based on the Ohrkan cohort study. A total of 2 149 9th graders in the City of Regensburg (mostly aged 15-16 years) were recruited between 2009-2011. At 2.5-year follow-up, the participants were asked again about leisure noise exposure. Both at baseline (O-I) and in the follow-up (O-II), self-reported frequency of participation in noisy activities was combined with literature-based values of usual sound levels to calculate the total weekly noise exposure. This exposure was compared to the lower exposure action value (lEAV) of 80 dB(A) given by the occupational health and safety regulations. Logistic regression was used to determine the factors associated with leisure noise exposure above the lEAV. Results Exposure data from both time points were available for 1 704 adolescents (54 % female). The percentage of participants who were exposed to leisure noise exceeding the lEAV increased from 75 to 92 % due to more persons visiting discotheques in O-II. In both surveys, the activity reported by the highest percentage of participants and with the longest exposure duration was listening to pop music via portable listening devices (PLD) although the proportion of users decreased slightly. Not being a pupil affected PLD use at volume levels >80 dB (A) whereas older age was associated with noise exposure in discotheques. Conclusions O-II shows that adolescents are engaged in leisure activities under harmful noise levels and that noise exposure sources are changing with age. These issues should be considered in the developing of prevention programs.

Perfluorooctanoic acid (PFOA) has been associated with various health effects, including immunotoxicity. This study aimed to examine associations between PFOA serum levels above the intervention threshold level (HBM-II, 10 µg/L) and diphtheria, tetanus and SARS-CoV-2 antibody concentrations among adult residents with increased internal PFOA. A total of 662 questionnaire data points and vaccination passports were collected and blood samples were used to determine PFOA serum levels and diphtheria, tetanus and SARS-CoV-2 antibody concentrations. Logistic regression modelling was used to examine potential associations. The median PFOA concentration was 9.17 µg/L with 45.2% exceeding the HBM-II. Of participants with at least one vaccination, 48.1% had reliable protection against diphtheria and 91.9% against tetanus. Antibodies against SARS-CoV-2 spike and nucleocapsid protein were detected in 96.4% and 53.8%, respectively. Age was a significant predictor for lack of immunity against diphtheria (OR = 3.6 (95% CI: 2.3; 5.7)) in the age group ≥60. No association was found between PFOA levels and SARS-CoV-2 N antibody concentrations. After adjusting for age group, PFOA serum concentrations above the intervention threshold were not associated with lower diphtheria or SARS-CoV-2 N antibody concentrations in the adult population. Further studies are needed to determine whether PFOA exposure has a long-term effect on the immune system.

Zusammenfassung: Hintergrund und Ziel In Kohortenstudien kann der Verlust von Teilnehmern während der Nachbeobachtungsphasen zu Verzerrungen führen, wenn sich Teilnehmer und Nichtteilnehmer unterscheiden. Viele Studien haben den Einfluss soziodemografischer und gesundheitlicher Faktoren auf die Teilnahmebereitschaft untersucht, es liegen jedoch nur relativ wenige Studien für schulbasierte Kohorten vor. Ziel dieser Arbeit ist die Bestimmung von Prädiktoren der Teilnahmebereitschaft im Rahmen der Ohrkan Kohortenstudie, die die Exposition von Jugendlichen gegenüber Freizeitlärm und mögliche Effekte auf das Hörvermögen im Zeitverlauf untersucht. Methoden Die Daten dieser Studie basieren auf den Angaben der Ohrkankohorte (n=2148), die 2009–2011 (O-I) unter den Neuntklässlern weiterführender Schulen in Regensburg rekrutiert und 2012–14 (O-II) und 2015–16 (O-III) nachbefragt wurde. Ergebnisse Die Teilnahmewahrscheinlichkeit in O-II und O-III war höher für Personen ohne Migrationshintergrund, die zu Studienbeginn das Gymnasium besuchten und deren Eltern ein höheres Bildungsniveau hatten oder zusammenlebten. Auch nahmen Personen, die in den letzten 2,5 Jahren ihren Wohnort nicht gewechselt hatten, 3-mal so häufig teil wie Befragte mit Wohnortwechsel. Schlussfolgerung Die Kenntnis von Merkmalen der Studienteilnehmer, die die Teilnahmebereitschaft vorhersagen, ermöglicht durch gezielte Ansprache den Verlust von Studienteilnehmern zu reduzieren bzw. die statistische Korrektur von fehlenden Daten.

The role of perfluorooctanoic acid (PFOA) on antibody titres following vaccination in adults is not heterogeneous. High levels of anti-spike IgG have been reported following mRNA-based vaccinations. This study aimed to explore the association between PFOA exposure and exposure to SARS-CoV-2 antigen on SARS-CoV-2 anti-spike antibodies, particularly on the IgG subclasses in adult residents with increased internal PFOA exposure due to past PFOA drinking water contamination. A self-administered questionnaire was completed, and vaccination data was checked against the vaccination passport. PFOA concentration and IgG subclass titres were analysed in serum. Most study participants had three vaccinations (518; 78.6%). IgG was dominated by IgG4, a subclass that is largely unable to activate effector responses, for 8.3% of the participants, and only in the group of participants with three vaccinations. A generalised linear model was used to assess the relationship between PFOA serum concentration and IgG subclasses. After adjusting for age, a significant positive association was found between the number of vaccinations, self-reported infections and higher IgG subclasses concentrations. Age and PFOA concentration did not show a significant association with the concentration of any IgG subclass. Thus, the internal PFOA exposure was not associated with impaired immune response with regard to anti-spike SARS-CoV-2 IgG.