Lung diffusing capacity for nitric oxide measured by two commercial devices: a randomised crossover comparison in healthy adults.

In Europe, two commercial devices are available to measure combined single-breath diffusing capacity of the lung for nitric oxide (D LNO) and carbon monoxide (D LCO) in one manoeuvre. Reference values were derived by pooling datasets from both devices, but agreement between devices has not been established. We conducted a randomised crossover trial in 35 healthy adults (age 40.0±15.5 years, 51% female) to compare D LNO (primary end-point) between MasterScreen™ (Vyaire Medical, Mettawa, IL, USA) and HypAir (Medisoft, Dinant, Belgium) devices during a single visit under controlled conditions. Linear mixed models were used adjusting for device and period as fixed effects and random intercept for each participant. Difference in D LNO between HypAir and MasterScreen was 24.0 mL·min-1·mmHg-1 (95% CI 21.7-26.3). There was no difference in D LCO (-0.03 mL·min-1·mmHg-1, 95% CI -0.57-0.12) between devices while alveolar volume (V A) was higher on HypAir compared to MasterScreen™ (0.48 L, 95% CI 0.45-0.52). Disparity in the estimation of V A and the rate of NO uptake (KNO=D LNO/V A) could explain the discrepancy in D LNO between devices. Disparity in the estimation of V A and the rate of CO uptake (KCO=D LCO/V A) per unit of V A offset each other resulting in negligible discrepancy in D LCO between devices. Differences in methods of expiratory gas sampling and sensor specifications between devices likely explain these observations. These findings have important implications for derivation of D LNO reference values and comparison of results across studies. Until this issue is resolved, reference values, established on the respective devices, should be used for test interpretation.

Human-biomonitoring and individual soil measurements for children and mothers in an area with recently detected mercury-contaminations and public health concerns: a cross-sectional study.

In this study, we assessed intracorporal mercury concentrations in subjects living on partially mercury-contaminated soils in a defined area in Switzerland. We assessed 64 mothers and 107 children who resided in a defined area for at least 3 months. Mercury in biological samples (urine and hair) was measured, a detailed questionnaire was administered for each individual, and individual mercury soil values were obtained. Human biomonitoring results were compared with health-related and reference values. Mothers and children in our study had geometric means (GMs) of 0.22 µg Hg/g creatinine in urine (95th percentile (P95) = 0.85 µg Hg/g) and 0.16 µg Hg/g (P95 = 0.56 µg Hg/g), respectively. In hair, mothers and children had GMs of 0.21 µg Hg/g (P95 = 0.94 µg/g) and 0.18 µg/g (P95 = 0.60 µg/g), respectively. We found no evidence for an association between mercury values in soil and those in human specimens nor for a health threat in residential mothers and children.

Predicted Mercury Soil Concentrations from a Kriging Approach for Improved Human Health Risk Assessment.

Health-risks from contaminated soils are assessed all over the world. An aspect that many risk assessments share is the heterogeneity in the distribution of contaminants. In a preceding study, we assessed potential health-risks for mothers and children living on mercury-contaminated soils in Switzerland using human biomonitoring-values (HBM) and soil samples. We assessed 64 mothers and 107 children who had resided in a defined area for at least 3 months. HBM-concentrations for mercury in urine and hair were measured, a detailed questionnaire was administered for each individual, and more than 4000 individual mercury soil values were obtained in 2015. In this study, we aimed at investigating possible associations of mercury soil- and HBM-values by re-analyzing our data, using predictions of the mercury concentrations at the exact location of the participant’s homes with a kriging approach. Although kriging proved to be a useful method to predict mercury soil concentrations, we did not detect an association between mercury soil- and HBM-values, in agreement with earlier findings. Benefits of geostatistical methods seem to be limited in the context of our study. Conclusions made in our preceding study about potential health risks for the residential population are robust and not altered by the current study.

Association of Endotoxin and Allergens with Respiratory and Skin Symptoms: A Descriptive Study in Laboratory Animal Workers.

BACKGROUND: In laboratory animal work, allergens are classically considered to play a prominent role in generation of respiratory and skin symptoms. However, recent development may have changed working conditions and require an updating of preventive measures. OBJECTIVE: In workers exposed to a range of animals besides laboratory mice and rats the relative role of endotoxin, irritants, and allergens in symptom generation was assessed for updating preventative measures and health surveillance. METHODS: Eligible workers were recruited from university units in which exposure to rats and/or mice, occurrence of respiratory and/or skin symptoms, and/or a history of animal bites had been reported. Exposure to endotoxin and rat and mouse allergen was assessed (71 half-day personal samples). 'Symptomatic' was defined by work-related ocular, nasal, respiratory, or skin symptoms. A concentration of specific IgE against rat or mouse (e87 and e88) ≥0.35 kU/l defined sensitization. Sensitivity analyses examined the effect of alternative exposure indicators and definitions of 'sensitized' and 'symptomatic'. RESULTS: From 302 eligible workers, 177 participated. There were 121 and 41 workers in the asymptomatic and non-sensitized and symptomatic but non-sensitized group, respectively. Eight subjects were symptomatic and sensitized. Six sensitized subjects were asymptomatic. One participant could not be assigned to a subgroup. Airborne endotoxin and allergen concentrations were mostly below 20 EU m-3 or the detection limit, respectively. Clinical history showed that irritants and sensitizers other than mouse/rat allergen or endotoxin were a major cause of symptoms. Results were sensitive to the selected exposure indicator and the definition of 'symptomatic'. CONCLUSIONS: Health surveillance programs need to be adapted to include a larger range of allergens and pay more attention to irritants.

Can serum cytokine profile discriminate irritant-induced and allergen-induced symptoms? A cross-sectional study in workers mostly exposed to laboratory animals.

BACKGROUND: In workers exposed mostly to laboratory animals (LA), symptoms may be due to irritants or allergens. Correct aetiological diagnosis is important for health surveillance. OBJECTIVES: This study aims to test whether work-related (WR) allergen-induced symptoms are associated with a cytokine profile distinct from that due to irritants. METHODS: In a cross-sectional study (n=114), WR respiratory and/or skin symptoms were assessed through a standardised clinical examination and sensitisation to rat and/or mouse allergen determined by serum immunoglobulin E. Serum cytokine concentrations were measured by multiplex assays. The predefined cytokine profiles 'sensitiser' (interleukin (IL)-4, IL-5, IL-13, eotaxin-1) and 'irritation' (IL-8, IL-17A, IL-17F, IL-22) were considered positive, when ≥3 concentrations exceeded the 95th percentile of the asymptomatic non-sensitised group. Results were examined by hierarchical clustering analyses (HCA) and multiple linear regression. Explorative analyses were carried out for nine additional cytokines. Exposure to allergens and endotoxin was assessed in a subpopulation. RESULTS: The prevalence of the profile 'irritation' was comparable in 28 symptomatic non-sensitised workers and 71 asymptomatic non-sensitised workers. HCA showed that nearly all symptomatic non-sensitised workers were gathered in two subclusters, characterised by high IL-17A levels, but different IL-8 levels. Multiple linear regression identified drug consumption and current complaints as confounders. Sensitised subjects were too few (n=14) for testing the profile 'sensitiser'. CONCLUSIONS: In this unselected population of LA workers, the profile 'irritation' did not prove to be a valuable health surveillance tool. Low power precluded assessment of the profile 'sensitiser'. The increased IL-17A concentration may originate from irritative constituents of organic dust.