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Clinical and Experimental Allergy :... May 2021Experimental challenge studies have shown that pollen can have early and delayed effects on the lungs and airways. Here, we qualitatively and quantitatively synthesize... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Experimental challenge studies have shown that pollen can have early and delayed effects on the lungs and airways. Here, we qualitatively and quantitatively synthesize the evidence of outdoor pollen exposure on various lung function and airway inflammation markers in community-based studies.
METHODS
Four online databases were searched: Medline, Web of Science, CINAHL and Google Scholar. The search strategy included terms relating to both exposure and outcomes. Inclusion criteria were human-based studies published in English that were representative of the community. Additionally, we only considered cross-sectional or short-term longitudinal studies which investigated pollen exposure by levels or season. Study quality assessment was performed using the Newcastle-Ottawa scale. Meta-analysis was conducted using random-effects models.
RESULTS
We included 27 of 6551 studies identified from the search. Qualitative synthesis indicated associations between pollen exposure and predominantly type-2 inflammation in both the upper and lower airways, but little evidence for lung function changes. People with ever asthma and/or seasonal allergic rhinitis (SAR) were at higher risk of such airway inflammation. Meta-analysis confirmed a positive relationship between pollen season, eosinophilia and eosinophil cationic protein (ECP) in people with ever SAR but the results between studies were highly variable. Heterogeneity was reduced after further subgrouping by age, and the forest plots indicated that eosinophilic airway inflammation to outdoor pollen exposure increased with age.
CONCLUSION
Among people with ever asthma and ever SAR, exposure to increased ambient pollen triggers type-2 upper and lower airway inflammation rather than a non-specific or innate inflammation. These findings can lead to the formulation of specific pollen immunotherapy for susceptible individuals. Future research should be directed towards investigating lagged associations and effect modifications using larger and more generalized populations.
SYSTEMATIC REVIEW REGISTRATION
CRD42020146981 (PROSPERO).
Topics: Asthma; Desensitization, Immunologic; Eosinophil Cationic Protein; Eosinophilia; Humans; Inflammation; Lung; Rhinitis, Allergic, Seasonal
PubMed: 33539034
DOI: 10.1111/cea.13842 -
The Science of the Total Environment Feb 2021Studies have demonstrated an adverse role of outdoor allergens on respiratory symptoms. It is unknown whether this effect is independent or synergistic of outdoor air...
BACKGROUND
Studies have demonstrated an adverse role of outdoor allergens on respiratory symptoms. It is unknown whether this effect is independent or synergistic of outdoor air pollutants.
METHODS
We systematically reviewed all epidemiological studies that examined interaction effects between counts of outdoor airborne allergens (pollen, fungal spores) and air pollutants, on any respiratory health outcome in children and adults. We searched the MEDLINE, EMBASE and Scopus databases. Each study was summarized qualitatively and assessed for quality and risk of bias (International Prospective Register for Systematic Reviews, registration number CRD42020162571).
RESULTS
Thirty-five studies were identified (15 timeseries, eight case-crossovers, 11 panels and one cohort study), of which 12 reported a significant statistical interaction between an allergen and air pollutant. Eight interactions were related to asthma outcomes, including one on lung function measures and wheeze, three to medical consultations for pollinosis and one to allergic symptoms (nasal, ocular or bronchial). There was no consensus as to which allergen or air pollutant is more likely to interact. No study investigated whether interactions are stronger in atopic individuals.
CONCLUSION
Despite strong evidence from small experimental studies in humans, only a third of studies identified significant allergen-pollutant interactions using common epidemiological study designs. Exposure misclassification, failure to examine subgroups at risk, inadequate statistical power or absence of population-level effects are possible explanations.
Topics: Adult; Air Pollutants; Air Pollution; Allergens; Child; Cohort Studies; Humans; Pollen
PubMed: 33310575
DOI: 10.1016/j.scitotenv.2020.143924 -
International Journal of Food Sciences... Aug 2021The aim of this systematic review and meta-analysis was to evaluate the effect of probiotics, parabiotics, synbiotics, fermented foods and other microbial forms on... (Meta-Analysis)
Meta-Analysis
The effect of probiotics, parabiotics, synbiotics, fermented foods and other microbial forms on immunoglobulin production: a systematic review and meta-analysis of clinical trials.
The aim of this systematic review and meta-analysis was to evaluate the effect of probiotics, parabiotics, synbiotics, fermented foods and other microbial forms on immunoglobulin production. We searched PubMed, Scopus, Web of Science, National Institute of Health Clinical Trials Register, and Cochrane Central Register of Clinical Trials, up to February 2020. All clinical trials that investigated the effects of oral intake of probiotics, parabiotics, synbiotics, fermented foods and other microbial forms on immunoglobulin (Ig)A, IgE, Japanese cedar pollen (JCP)-specific IgE, IgG, and IgM, for a duration of >7 days were included. Fifty-nine studies met the inclusion criteria, of these 54 studies were included in the analysis. The results indicated a significant increase in salivary IgA secretion rate (SMD = 0.21, 95% CI 0.02-0.39), while no significant effect was observed on other Igs. In conclusion, mentioned supplementation induced a small but significant effect on salivary secretion rate of IgA.
Topics: Fermented Foods; Humans; Immunoglobulin A; Immunoglobulins; Prebiotics; Probiotics; Synbiotics
PubMed: 33307904
DOI: 10.1080/09637486.2020.1857710 -
Environmental Health : a Global Access... Dec 2020Exposure to heat, air pollution, and pollen are associated with health outcomes, including cardiovascular and respiratory disease. Studies assessing the health impacts...
BACKGROUND
Exposure to heat, air pollution, and pollen are associated with health outcomes, including cardiovascular and respiratory disease. Studies assessing the health impacts of climate change have considered increased exposure to these risk factors separately, though they may be increasing simultaneously for some populations and may act synergistically on health. Our objective is to systematically review epidemiological evidence for interactive effects of multiple exposures to heat, air pollution, and pollen on human health.
METHODS
We systematically searched electronic literature databases (last search, April 29, 2019) for studies reporting quantitative measurements of associations between at least two of the exposures and mortality from any cause and cardiovascular and respiratory morbidity and mortality specifically. Following the Navigation Guide systematic review methodology, we evaluated the risk of bias of individual studies and the overall quality and strength of evidence.
RESULTS
We found 56 studies that met the inclusion criteria. Of these, six measured air pollution, heat, and pollen; 39 measured air pollution and heat; 10 measured air pollution and pollen; and one measured heat and pollen. Nearly all studies were at risk of bias from exposure assessment error. However, consistent exposure-response across studies led us to conclude that there is overall moderate quality and sufficient evidence for synergistic effects of heat and air pollution. We concluded that there is overall low quality and limited evidence for synergistic effects from simultaneous exposure to (1) air pollution, pollen, and heat; and (2) air pollution and pollen. With only one study, we were unable to assess the evidence for synergistic effects of heat and pollen.
CONCLUSIONS
If synergistic effects between heat and air pollution are confirmed with additional research, the health impacts from climate change-driven increases in air pollution and heat exposure may be larger than previously estimated in studies that consider these risk factors individually.
Topics: Air Pollution; Cardiovascular Diseases; Hot Temperature; Humans; Pollen; Respiratory Tract Diseases
PubMed: 33287833
DOI: 10.1186/s12940-020-00681-z -
Clinical Otolaryngology : Official... Jan 2021Allergic rhinitis (AR) is a common inflammatory condition of the nasal mucosa affecting approximately 20% of the population worldwide. Current therapies include... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Allergic rhinitis (AR) is a common inflammatory condition of the nasal mucosa affecting approximately 20% of the population worldwide. Current therapies include intranasal antihistamines, corticosteroids, subcutaneous and sublingual immunotherapy (SLIT). This review and meta-analysis assess the efficacy of SLIT in the management of grass pollen-induced AR in adults.
METHODS
Ovid EMBASE, Ovid EBM Reviews, Cochrane Central Register of Controlled Trials, Ovid MedLine and PubMed were searched using the following terms: 'sublingual immunotherapy', 'SLIT', 'rhinitis', 'allergic rhinitis', 'rhinosinusitis' and 'rhino-conjunctivitis'. All included studies were double-blind, placebo-controlled and randomised trials. Primary outcome was symptom score and secondary outcome included quality of life and safety profile. Meta-analysis of symptom improvement was carried out.
RESULTS
Six studies were identified with 979 subjects randomly allocated to SLIT and 992 to a placebo control. All studies reported an improvement in symptoms with SLIT, with five reaching statistical significance (P < .05). Four studies reported statistically significant improvement in quality of life (P < .05). Oral pruritus was the most common adverse event reported. The overall risk of bias was high in 50% of the studies.
CONCLUSIONS
Sublingual immunotherapy was a safe and effective treatment for grass pollen-induced AR in adults, and therefore, consideration should be given to its use for moderate-to-severe disease in the UK-wide population.
Topics: Adolescent; Adult; Aged; Allergens; Humans; Middle Aged; Pollen; Rhinitis, Allergic; Sublingual Immunotherapy; Young Adult
PubMed: 32979035
DOI: 10.1111/coa.13651 -
The Cochrane Database of Systematic... Sep 2020Asthma is a common long-term respiratory disease affecting approximately 300 million people worldwide. Approximately half of people with asthma have an important... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Asthma is a common long-term respiratory disease affecting approximately 300 million people worldwide. Approximately half of people with asthma have an important allergic component to their disease, which may provide an opportunity for targeted treatment. Sublingual immunotherapy (SLIT) aims to reduce asthma symptoms by delivering increasing doses of an allergen (e.g. house dust mite, pollen extract) under the tongue to induce immune tolerance. Fifty-two studies were identified and synthesised in the original Cochrane Review in 2015, but questions remained about the safety and efficacy of sublingual immunotherapy for people with asthma.
OBJECTIVES
To assess the efficacy and safety of sublingual immunotherapy compared with placebo or standard care for adults and children with asthma.
SEARCH METHODS
The original searches for trials from the Cochrane Airways Group Specialised Register (CAGR), ClinicalTrials.gov, WHO ICTRP, and reference lists of all primary studies and review articles found trials up to 25 March 2015. The most recent search for trials for the current update was conducted on 29 October 2019.
SELECTION CRITERIA
We included parallel randomised controlled trials, irrespective of blinding or duration, that evaluated sublingual immunotherapy versus placebo or as an add-on to standard asthma management. We included both adults and children with asthma of any severity and with any allergen-sensitisation pattern. We included studies that recruited participants with asthma, rhinitis, or both, providing at least 80% of trial participants had a diagnosis of asthma. We selected outcomes to reflect recommended outcomes for asthma clinical trials and those most important to people with asthma. Primary outcomes were asthma exacerbations requiring a visit to the emergency department (ED) or admission to hospital, validated measures of quality of life, and all-cause serious adverse events (SAEs). Secondary outcomes were asthma symptom scores, exacerbations requiring systemic corticosteroids, response to provocation tests, and dose of inhaled corticosteroids (ICS).
DATA COLLECTION AND ANALYSIS
Two review authors independently screened the search results for included trials, extracted numerical data, and assessed risk of bias, all of which were cross-checked for accuracy. Any disagreements were resolved by discussion. We analysed dichotomous data as odds ratios (ORs) or risk differences (RDs) using study participants as the unit of analysis; we analysed continuous data as mean differences (MDs) or standardised mean differences (SMDs) using random-effects models. We considered the strength of evidence for all primary and secondary outcomes using the GRADE approach.
MAIN RESULTS
Sixty-six studies met the inclusion criteria for this update, including 52 studies from the original review. Most studies were double-blind and placebo-controlled, varied in duration from one day to three years, and recruited participants with mild or intermittent asthma, often with comorbid allergic rhinitis. Twenty-three studies recruited adults and teenagers; 31 recruited only children; three recruited both; and nine did not specify. The pattern of reporting and results remained largely unchanged from the original review despite 14 further studies and a 50% increase in participants studied (5077 to 7944). Reporting of primary efficacy outcomes to measure the impact of SLIT on asthma exacerbations and quality of life was infrequent, and selective reporting may have had a serious effect on the completeness of the evidence; 16 studies did not contribute any data, and a further six studies could only be included in a post hoc analysis of all adverse events. Allocation procedures were generally not well described; about a quarter of the studies were at high risk of performance or detection bias (or both); and participant attrition was high or unknown in around half of the studies. The primary outcome in most studies did not align with those of interest to the review (mostly asthma or rhinitis symptoms), and only two small studies reported our primary outcome of exacerbations requiring an ED or hospital visit; the pooled estimate from these studies suggests SLIT may reduce exacerbations compared with placebo or usual care, but the evidence is very uncertain (OR 0.35, 95% confidence interval (CI) 0.10 to 1.20; n = 108; very low-certainty evidence). Nine studies reporting quality of life could not be combined in a meta-analysis and, whilst the direction of effect mostly favoured SLIT, the effects were often uncertain and small. SLIT likely does not increase SAEs compared with placebo or usual care, and analysis by risk difference suggests no more than 1 in 100 people taking SLIT will have a serious adverse event (RD -0.0004, 95% CI -0.0072 to 0.0064; participants = 4810; studies = 29; moderate-certainty evidence). Regarding secondary outcomes, asthma symptom and medication scores were mostly measured with non-validated scales, which precluded meaningful meta-analysis or interpretation, but there was a general trend of SLIT benefit over placebo. Changes in ICS use (MD -17.13 µg/d, 95% CI -61.19 to 26.93; low-certainty evidence), exacerbations requiring oral steroids (studies = 2; no events), and bronchial provocation (SMD 0.99, 95% CI 0.17 to 1.82; low-certainty evidence) were not often reported. Results were imprecise and included the possibility of important benefit or little effect and, in some cases, potential harm from SLIT. More people taking SLIT had adverse events of any kind compared with control (OR 1.99, 95% CI 1.49 to 2.67; high-certainty evidence; participants = 4251; studies = 27), but events were usually reported to be transient and mild. Lack of data prevented most of the planned subgroup and sensitivity analyses.
AUTHORS' CONCLUSIONS
Despite continued study in the field, the evidence for important outcomes such as exacerbations and quality of life remains too limited to draw clinically useful conclusions about the efficacy of SLIT for people with asthma. Trials mostly recruited mixed populations with mild and intermittent asthma and/or rhinitis and focused on non-validated symptom and medication scores. The review findings suggest that SLIT may be a safe option for people with well-controlled mild-to-moderate asthma and rhinitis who are likely to be at low risk of serious harm, but the role of SLIT for people with uncontrolled asthma requires further evaluation.
Topics: Adolescent; Adult; Animals; Asthma; Child; Disease Progression; Hospitalization; Humans; Placebos; Pollen; Pyroglyphidae; Quality of Life; Randomized Controlled Trials as Topic; Rhinitis, Allergic; Sublingual Immunotherapy
PubMed: 32926419
DOI: 10.1002/14651858.CD011293.pub3 -
Environmental Research Oct 2020Exposure to Plant Protection Products, PPPs, (fungicides, herbicides and insecticides) is a significant stressor for bees and other pollinators, and has recently been...
Exposure to Plant Protection Products, PPPs, (fungicides, herbicides and insecticides) is a significant stressor for bees and other pollinators, and has recently been the focus of intensive debate and research. Specifically, exposure through contaminated pollen and nectar is considered pivotal, as it presents the highest risk of PPP exposure across all bee species. However, the actual risk that multiple PPP residues might pose to non-target species is difficult to assess due to the lack of clear evidence of their actual concentrations. To consolidate the existing knowledge of field-realistic residues detected in pollen and nectar directly collected from plants, we performed a systematic literature review of studies over the past 50 years (1968-2018). We found that pollen was the matrix most frequently evaluated and, of the compounds investigated, the majority were detected in pollen samples. Although the overall most studied category of PPPs were the neonicotinoid insecticides, the compounds with the highest median concentrations of residues in pollen were: the broad spectrum carbamate carbofuran (1400 ng/g), the fungicide and nematicide iprodione (524 ng/g), and the organophosphate insecticide dimethoate (500 ng/g). In nectar, the highest median concentration of PPP residues detected were dimethoate (1595 ng/g), chlorothalonil (76 ng/g), and the insecticide phorate (53.5 ng/g). Strong positive correlation was observed between neonicotinoid residues in pollen and nectar of cultivated plant species. The maximum concentrations of several compounds detected in nectar and pollen were estimated to exceed the LD for honey bees, bumble bees and four solitary bee species, by several orders of magnitude. However, there is a paucity of information for the biggest part of the world and there is an urgent need to expand the range of compounds evaluated in PPP studies.
Topics: Animals; Bees; Insecticides; Neonicotinoids; Pesticide Residues; Plant Nectar; Pollen; Pollination
PubMed: 32795671
DOI: 10.1016/j.envres.2020.109873 -
International Journal of Environmental... Jun 2020The urban forest is a green infrastructure system that delivers multiple environmental, economic, social and health services, and functions in cities. Environmental...
The urban forest is a green infrastructure system that delivers multiple environmental, economic, social and health services, and functions in cities. Environmental benefits of urban trees are well understood, but no review to date has examined how urban trees affect human health. This review provides a comprehensive summary of existing literature on the health impacts of urban trees that can inform future research, policy, and nature-based public health interventions. A systematic search used keywords representing human health, environmental health, and urban forestry. Following screening and appraisal of several thousand articles, 201 studies were conceptually sorted into a three-part framework. Reducing Harm, representing 41% of studies, includes topics such as air pollution, ultraviolet radiation, heat exposure, and pollen. Restoring Capacities, at 31%, includes attention restoration, mental health, stress reduction, and clinical outcomes. Building Capacities, at 28%, includes topics such as birth outcomes, active living, and weight status. The studies that were reviewed show substantial heterogeneity in purpose and method yet indicate important health outcomes associated with people's exposure to trees. This review will help inform future research and practice, and demonstrates why urban forest planning and management should strategically promote trees as a social determinant of public health.
Topics: Cities; Forestry; Forests; Humans; Trees; Ultraviolet Rays; Urban Health
PubMed: 32570770
DOI: 10.3390/ijerph17124371 -
Chemosphere Nov 2020Honey bee mortality and colony losses have been reported worldwide. Although this phenomenon is caused by a combination of factors, agrochemicals have received special...
Honey bee mortality and colony losses have been reported worldwide. Although this phenomenon is caused by a combination of factors, agrochemicals have received special attention due to their potential effects on bees. In agricultural and urban environments bees are exposed to several compounds that may interact in unexpected ways, but information on the extent of pesticide exposure remains unclear. Several monitoring studies have been conducted to evaluate the field-realistic exposure of bees to pesticides after their release on the market. However, their outputs are difficult to compare and harmonize due to differences in the analytical methodologies and the sampling protocols (e.g. number of screened compounds and analysed samples, and detection limits (LODs)). Here, we hypothesize that the analytical methodologies used in the monitoring studies may strongly affect the pesticide occurrences in pollen underestimating the real pesticide exposure. By mean of a systematic literature review, we have collected relevant information on pesticide contaminations in the honey bee-collected pollen. Our findings showed that the pesticide occurrences were associated with the analytical methodologies and the real pesticide exposure has likely been underestimated in some monitoring studies. For four highly toxic compounds, the LOD used in these monitoring studies exceeded the doses that cause toxic effects on honey bees. We recommend that, especially for the highly toxic compounds, the LODs used in the monitoring studies should be low enough to exclude lethal or sublethal effects on bees and avoid "false negative" samples.
Topics: Agriculture; Animals; Bees; Environmental Monitoring; Environmental Pollutants; Honey; Insecticides; Pesticides; Pollen
PubMed: 32563069
DOI: 10.1016/j.chemosphere.2020.127358 -
Allergologia Et Immunopathologia 2020Apitherapy represents a certain form of complementary and alternative medicine that uses bee products in combination with other methods from this field. One of the basic...
BACKGROUND
Apitherapy represents a certain form of complementary and alternative medicine that uses bee products in combination with other methods from this field. One of the basic concepts of this type of medicine is that all diseases can be treated using apitherapy. This study was performed to assess the recommendations from authors of books on apitherapy regarding the treatment of seasonal allergic rhinitis and compare them to findings from the scientific literature.
METHODS
One hundred and twenty-nine books on apitherapy were analysed regarding recommendations for allergic seasonal rhinitis. Scientific evidence regarding the efficacy of using various bee products was searched via PubMed and JUSTfind.
RESULTS
Only 38.8% of the apitherapy books mentioned seasonal allergic rhinitis. Among these books, we found 29 different recommendations in favour of bee products and one against the use of honey. The most reasonable recommendation according to clinical studies on the subject, namely the use of a mix of honey and pollen, was only found once (0.8%).
CONCLUSIONS
The large discrepancies and number of different recommendations demonstrate that apitherapy is not a consistent type of medicine. The recommendations regarding seasonal allergic rhinitis in the vast majority of apitherapy books cannot be considered adequate when compared to the scientific findings.
Topics: Apitherapy; Humans; Rhinitis, Allergic, Seasonal; Treatment Outcome
PubMed: 32451131
DOI: 10.1016/j.aller.2020.03.015