Association between short-term pollen exposure and blood pressure in adults: A repeated-measures study.

BACKGROUND: Recent studies have related high pollen concentrations to increased cardiovascular morbidity and mortality, yet very little research concerns pre-clinical cardiovascular health, including effects on blood pressure (BP). The EPOCHAL panel study investigated the exposure-response relationship between ambient pollen exposure and systolic and diastolic BP in adults. METHODS: BP was measured in 302 adults with and in 94 without pollen allergy during the pollen season, on approximately 16 days per person (6253 observations). Average individually-relevant pollen exposure in the 96 h prior to each BP measurement was calculated by summing up the averages of all ambient pollen concentrations to which the individual was found to be sensitized in a skin prick test, and which originated from seven highly allergenic pollen types (hazel, alder, birch, ash, grasses, mugwort and ragweed). Generalized additive mixed models were used to study the association between mean individually-relevant pollen exposure in the last 96 h and BP, adjusting for individual and environmental time-varying covariates. Effect modification by pollen allergy status, sex and BMI was evaluated. RESULTS: Positive non-linear associations between individually-relevant pollen exposure and both systolic and diastolic BP were found in the allergic but not in the non-allergic group. BP increased sharply for exposures from zero to 60/80 pollen/m3 (diastolic/systolic BP), followed by a tempered further increase at higher concentrations. Increases of 2.00 mmHg [95% confidence interval (CI): 0.80-3.19] in systolic and 1.51 mmHg [95% CI: 0.58-2.45] in diastolic BP were associated with 96-h average pollen exposure of 400 pollen/m3, compared to no exposure. Obesity and female sex were associated with larger BP increases. CONCLUSIONS: The finding that short-term pollen concentration is associated with increased systolic and diastolic BP in persons with pollen allergy strengthens the evidence that pollen may cause systemic health effects and trigger cardiovascular events.

Ambient pollen exposure and pollen allergy symptom severity in the EPOCHAL study.

BACKGROUND: Ambient pollen exposure causes nasal, ocular, and pulmonary symptoms in allergic individuals, but the shape of the exposure-response association is not well characterized. We evaluated this association and determined (1) whether symptom severity differs between subpopulations; (2) how the association changes over the course of the pollen season; and (3) which pollen exposure time lags affect symptoms. METHODS: Adult study participants (n = 396) repeatedly scored severity of nasal, ocular, and pulmonary allergic symptoms, resulting in three composite symptom scores. We calculated hourly individually relevant pollen exposure to seven allergenic plants (alder, ash, birch, hazel, grasses, mugwort, and ragweed) considering personal sensitization and exposure time lags of up to 96 h. We fitted generalized additive mixed models, with a random personal intercept, adjusting for weather and air pollution as potential time-varying confounders. RESULTS: We identified a clear nonlinear positive association between pollen exposure and ocular and nasal symptom severity in the pollen allergy group: Symptom severity increased steeply with increasing exposure initially, but attenuated beyond approximately 80 pollen/m3. We found no evidence of an exposure threshold, below which no symptoms occur. While recent pollen exposure in the last approximately 5 h affected symptoms most, associations lingered for up to 60 h. Grass pollen exposure (compared to tree pollen) and younger age (18-30 years, as opposed to 30-65 years) were both associated with higher nasal and ocular symptom severity. CONCLUSIONS: The lack of a threshold and attenuated dose-response curve may have implications for pollen warning systems, which may be revised to include multiday pollen concentrations in the future.

Personal radiofrequency electromagnetic field exposure of adolescents in the Greater London area in the SCAMP cohort and the association with restrictions on permitted use of mobile communication technologies at school and at home.

Personal measurements of radiofrequency electromagnetic fields (RF-EMF) have been used in several studies to characterise personal exposure in daily life, but such data are limitedly available for adolescents, and not yet for the United Kingdom (UK). In this study, we aimed to characterise personal exposure to RF-EMF in adolescents and to study the association between exposure and rules applied at school and at home to restrict wireless communication use, likely implemented to reduce other effects of mobile technology (e.g. distraction). We measured exposure to RF-EMF for 16 common frequency bands (87.5 MHz-3.5 GHz), using portable measurement devices (ExpoM-RF), in a subsample of adolescents participating in the cohort Study of Cognition, Adolescents and Mobile Phones (SCAMP) from Greater London (UK) (n = 188). School and home rules were assessed by questionnaire and concerned the school's availability of WiFi and mobile phone policy, and parental restrictions on permitted mobile phone use. Adolescents recorded their activities in real time using a diary app on a study smartphone, while characterizing their personal RF-EMF exposure in daily life, during different activities and times of the day. Data analysis was done for 148 adolescents from 29 schools who recorded RF-EMF data for a median duration of 47 h. The majority (74%) of adolescents spent part of their time at school during the measurement period. Median total RF-EMF exposure was 40 µW/m2 at home, 94 µW/m2 at school, and 100 µW/m2 overall. In general, restrictions at school or at home made little difference for adolescents' measured exposure to RF-EMF, except for uplink exposure from mobile phones while at school, which was found to be significantly lower for adolescents attending schools not permitting phone use at all, compared to adolescents attending schools allowing mobile phone use during breaks. This difference was not statistically significant for total personal exposure. Total exposure to RF-EMF in adolescents living in Greater London tended to be higher compared to exposure levels reported in other European countries. This study suggests that school policies and parental restrictions are not associated with a lower RF-EMF exposure in adolescents.

Rationale and Design of a Panel Study Investigating Six Health Effects of Airborne Pollen: The EPOCHAL Study.

Background: While airborne pollen is widely recognized as a seasonal cause of sneezing and itchy eyes, its effects on pulmonary function, cardiovascular health, sleep quality, and cognitive performance are less well-established. It is likely that the public health impact of pollen may increase in the future due to a higher population prevalence of pollen sensitization as well as earlier, longer, and more intense pollen seasons, trends attributed to climate change. The effects of pollen on health outcomes have previously been studied through cross-sectional design or at two time points, namely preceding and within the period of pollen exposure. We are not aware of any observational study in adults that has analyzed the dose-response relationship between daily ambient pollen concentration and cardiovascular, pulmonary, cognitive, sleep, or quality of life outcomes. Many studies have relied on self-reported pollen allergy status rather than objectively confirming pollen sensitization. In addition, many studies lacked statistical power due to small sample sizes or were highly restrictive with their inclusion criteria, making the findings less transferable to the "real world." Methods: The EPOCHAL study is an observational panel study which aims to relate ambient pollen concentration to six specific health domains: (1) pulmonary function and inflammation; (2) cardiovascular outcomes (blood pressure and heart rate variability); (3) cognitive performance; (4) sleep; (5) health-related quality of life (HRQoL); and (6) allergic rhinitis symptom severity. Our goal is to enroll 400 individuals with diverse allergen sensitization profiles. The six health domains will be assessed while ambient exposure to pollen of different plants naturally varies. Health data will be collected through six home nurse visits (at approximately weekly intervals) as well as 10 days of independent tracking of blood pressure, sleep, cognitive performance, HRQoL, and symptom severity by participants. Through repeated health assessments, we aim to uncover and characterize dose-response relationships between exposure to different species of pollen and numerous acute health effects, considering (non-)linearity, thresholds, plateaus and slopes. Conclusion: A gain of knowledge in pollen-health outcome relationships is critical to inform future public health policies and will ultimately lead toward better symptom forecasts and improved personalized prevention and treatment.

A real-world quality assessment study in six ExpoM-RF measurement devices.

Exposimeters measuring radiofrequency electromagnetic fields (RF-EMF) are commonly used to assess personal exposure to RF-EMF in real-life environments. They are usually calibrated in an anechoic chamber using single, well-defined signals such as the center frequency of each band, and standardized orientations, but it is not clear how different devices compare in the real environment where complex mixtures of signals from all directions are present. We thus tested the comparability of six ExpoM-RF exposimeters before and after calibration in an anechoic chamber by varying their position and orientation while repeatedly measuring 15 microenvironments (9 walking routes, 4 tram routes and 2 bus routes) on 6 different days. We modelled the geometric mean levels of RF-EMF as a function of orientation, position, device ID, whether the device was recently calibrated, correcting for the microenvironment in which each measurement took place. We found that systematic differences introduced by device ID, calibration, day of the week, orientation and position are relatively small compared to exposure differences between microenvironments. Any corrections (if desired) should include both device ID and calibration session, but would have a small impact considering the negligible differences between devices. This supports the validity of previous exposure measurement studies relying on ExpoM-RF devices, which did not correct for device ID. We further found that summarizing the exposure per microenvironment as geometric means results in better models than arithmetic means and medians, and recommend that further exposure assessment studies report observed levels as geometric means.

Food-Predicting Stimuli Differentially Influence Eye Movements and Goal-Directed Behavior in Normal-Weight, Overweight, and Obese Individuals.

Obese individuals have been shown to exhibit abnormal sensitivity to rewards and reward-predicting cues as for example food-associated cues frequently used in advertisements. It has also been shown that food-associated cues can increase goal-directed behavior but it is currently unknown, whether this effect differs between normal-weight, overweight, and obese individuals. Here, we investigate this question by using a Pavlovian-to-instrumental transfer (PIT) task in normal-weight (N = 20), overweight (N = 17), and obese (N = 17) individuals. Furthermore, we applied eye tracking during Pavlovian conditioning to measure the participants' conditioned response as a proxy of the incentive salience of the predicted reward. Our results show that the goal-directed behavior of overweight individuals was more strongly influenced by food-predicting cues (i.e., stronger PIT effect) than that of normal-weight and obese individuals (p < 0.001). The weight groups were matched for age, gender, education, and parental education. Eye movements during Pavlovian conditioning also differed between weight categories (p < 0.05) and were used to categorize individuals based on their fixation style into "high eye index" versus "low eye index" as well. Our main finding was that the fixation style exhibited a complex interaction with the weight category. Furthermore, we found that normal-weight individuals of the group "high eye index" had higher body mass index within the healthy range than individuals of the group "low eye index" (p < 0.001), but this relationship was not found within in the overweight or obese groups (p > 0.646). Our findings are largely consistent with the incentive sensitization theory predicting that overweight individuals are more susceptible to food-related cues than normal-weight controls. However, this hypersensitivity might be reduced in obese individuals, possibly due to habitual/compulsive overeating or differences in reward valuation.