Ambient air pollution exposure and incident adult asthma in a nationwide cohort of U.S. women.

RATIONALE: Limited prior data suggest an association between traffic-related air pollution and incident asthma in adults. No published studies assess the effect of long-term exposures to particulate matter less than 2.5 µm in diameter (PM2.5) on adult incident asthma. OBJECTIVES: To estimate the association between ambient air pollution exposures (PM2.5 and nitrogen dioxide, NO2) and development of asthma and incident respiratory symptoms. METHODS: The Sister Study is a U.S. cohort study of risk factors for breast cancer and other health outcomes (n = 50,884) in sisters of women with breast cancer (enrollment, 2003-2009). Annual average (2006) ambient PM2.5 and NO2 concentrations were estimated at participants' addresses, using a national land-use/kriging model incorporating roadway information. Outcomes at follow-up (2008-2012) included incident self-reported wheeze, chronic cough, and doctor-diagnosed asthma in women without baseline symptoms. MEASUREMENTS AND MAIN RESULTS: Adjusted analyses included 254 incident cases of asthma, 1,023 of wheeze, and 1,559 of chronic cough. For an interquartile range (IQR) difference (3.6 µg/m(3)) in estimated PM2.5 exposure, the adjusted odds ratio (aOR) was 1.20 (95% confidence interval [CI] = 0.99-1.46, P = 0.063) for incident asthma and 1.14 (95% CI = 1.04-1.26, P = 0.008) for incident wheeze. For NO2, there was evidence for an association with incident wheeze (aOR = 1.08, 95% CI = 1.00-1.17, P = 0.048 per IQR of 5.8 ppb). Neither pollutant was significantly associated with incident cough (PM2.5: aOR = 0.95, 95% CI = 0.88-1.03, P = 0.194; NO2: aOR = 1.00, 95% CI = 0.93-1.07, P = 0.939). CONCLUSIONS: Results suggest that PM2.5 exposure increases the risk of developing asthma and that PM2.5 and NO2 increase the risk of developing wheeze, the cardinal symptom of asthma, in adult women.

Airborne chemical pollution and children's asthma incidence rate in Minsk.

Introduction: Asthma manifestations are closely connected with air pollution. Discovering interconnection between concentrations of air pollutants and asthma incidence rate among children provides information for developing effective measures to reduce air pollution and improve population health. Study purpose was to carry out hygienic analysis of the influence of atmospheric air quality on the incidence rate of bronchial asthma of children in Minsk in 2009-2018. Methods: During 2019 retrospective health cohort study was conducted, data from stationary air quality monitoring posts were collected. Correlation analysis was conducted by determining the Pearson coefficient. Results: Ten-year levels of asthma incidence rate had a moderate downward trend; the highest levels were registered among 5-9-year-old children. 74.7% of all cases of asthma were registered among children under 10 years: 33,61% among 1-4-year-old and 41.09% - among 5-9-year-old. Results of the study showed that concentrations of ammonia, particulate matter (dust/aerosol undifferentiated in composition) and lead in Minsk were characterized by downward trend, carbon oxide and nitrogen dioxide concentrations remained unstable, elevated levels of formaldehyde remained near highways with heavy traffic. Strong evidence was found for concentrations of particulate matter (dust/aerosol undifferentiated in composition) (R = 0.76-0.85, p < 0.05), lead (R = 0.69-0.97, p < 0.05), ammonia (R = 0.64-0.72, p < 0.05) nitrogen dioxide (R = 0.63-0.8, p < 0.05) and children's asthma incidence rate. Conclusions: Obtained results indicate that particulate matter, lead, ammonia and nitrogen dioxide concentrations hesitation causes changes in children's asthma incidence levels. Not being the initial cause of the disease, they influence epidemic process and can be the target for preventive measures.

Long-term exposure to ambient air pollution and road traffic noise and asthma incidence in adults: The Danish Nurse cohort.

BACKGROUND: Ambient air pollution is likely a risk factor for asthma, and recent evidence suggests the possible relevance of road traffic noise. OBJECTIVES: We examined the associations of long-term exposure to air pollution and road traffic noise with adult-asthma incidence. METHODS: We followed 28,731 female nurses (age > 44 years) from the Danish Nurse Cohort, recruited in 1993 and 1999, for first hospital contact for asthma from 1977 until 2015. We estimated residential annual mean concentrations of particulate matter with diameter < 2.5 µm (PM2.5) since 1990 and nitrogen dioxide (NO2) since 1970 with the Danish DEHM/UBM/AirGIS modeling system, and road traffic noise (Lden) since 1970 with the Nord2000 model. Time-varying Cox regression models were used to associate air pollution and road traffic noise exposure with asthma incidence. RESULTS: During 18.6 years' mean follow-up, 528 out of 23,093 participants had hospital contact for asthma. The hazard ratios (HR) and 95% confidence intervals for asthma incidence associated with 3-year moving average exposures were 1.29 (1.03, 1.61) per 6.3 µg/m3 for PM2.5, 1.16 (1.07, 1.27) per 8.2 µg/m3 for NO2, and 1.12 (1.00, 1.25) per 10 dB for Lden. The HR for NO2 remained unchanged after adjustment for either PM2.5 or Lden, while the HRs for PM2.5 and Lden attenuated to unity after adjustment for NO2. CONCLUSIONS: Long-term exposure to air pollution was associated with adult-asthma incidence independently of road traffic noise, with NO2 most relevant. Road traffic noise was not independently associated with adult-asthma incidence.

Variability in Diagnosed Asthma in Young Children in a Large Pediatric Primary Care Network.

OBJECTIVE: Our objectives were to 1) quantify the frequency of wheezing episodes and asthma diagnosis in young children in a large pediatric primary care network and 2) assess the variability in practice-level asthma diagnosis, accounting for common asthma risk factors and comorbidities. We hypothesized that significant variability in practice-level asthma diagnosis rates would remain after adjusting for associated predictors. METHODS: We generated a retrospective longitudinal birth cohort of children who visited 1 of 31 pediatric primary care practices within the first 6 months of life from 1/2005 to 12/2016. Children were observed for up to 8 years or until the end of the observation window. We used multivariable discrete time survival models to evaluate predictors of asthma diagnosis by 3-month age intervals. We compared unadjusted and adjusted proportions of children diagnosed with asthma by practice. RESULTS: Of the 161,502 children in the cohort, 34,578 children (21%) received at least 1 asthma diagnosis. In multivariable modeling, male gender, minority race/ethnicity, gestational age <34 weeks, allergic rhinitis, food allergy, and prior wheezing episodes were associated with asthma diagnosis. After adjusting for variation in these predictors across practices, the cumulative incidence of asthma diagnosis by practice by age 6 years ranged from 11% to 47% (interquartile range: 24%-29%). CONCLUSIONS: Across pediatric primary care practices, adjusted incidence of asthma diagnosis by age 6 years ranged widely, though variation gauged by the interquartile range was more modest. Potential sources of practice-level variation, such as differing diagnosis thresholds and labeling of different wheezing phenotypes as "asthma," should be further investigated.

Occupational Asthma and Its Causation in the UK Seafood Processing Industry.

OBJECTIVES: The processing of seafood (fish and shellfish) for human consumption can lead to health consequences, including occupational asthma (OA). Several non-UK studies have reported both respiratory outcomes and airborne levels of major allergens in seafood processing. However, there is a paucity of such evidence in the UK land-based seafood processing sector, which employs some 20 000 workers. METHODS: University of Manchester's Surveillance of Work-related and Occupational Respiratory Disease (SWORD) reporting system has been interrogated over the period 1992-2017 to define the incidence rate of OA cases that can be ascribed to the UK land-based processing sector, and the seafood species implicated. Airborne allergen monitoring data undertaken at Health and Safety Executive's laboratory from 2003 to 2019 have also been collated. RESULTS: The estimated annual OA incidence rate in seafood processors was 70 [95% confidence intervals (CIs) 48.9, 91.1] per 100 000 workers compared with 2.9 (95% CIs 2.8, 3.1) in 'all other industries'. The annual calculated percentage trend in OA (1992-2017) was -8.1% (95% CIs -15.9, 0.4) in seafood processing showing a similar trend to 'all other industries' (mean -7.0%; 95% CIs -7.8, -6.1). Prawns and salmon/trout were notably implicated by SWORD as causative species related to OA. There is a general paucity of available UK airborne allergen monitoring data, particularly concerning processing salmon or trout. Available airborne monitoring for salmon parvalbumin in seven processors ranged between the limit of detection and 816 ng m-3 (n = 64). Available air monitoring levels of the major shellfish allergen (tropomyosin) during processing of crabs and prawns ranged between 1 and 101 600 ng m-3 (n = 280), highlighting that high levels of exposure can occur. CONCLUSIONS: These data show an excess incidence of OA in the UK seafood processing industry during 1992-2017, with limited airborne monitoring data for the processing of prawn, crab, and salmon suggesting that significant exposure to major seafood allergens can occur in this industry. Further investigation of current levels of respiratory ill-health and the sources of allergen exposure are warranted.

Altitude above 1500 m is a major determinant of asthma incidence. An ecological study.

BACKGROUND: Previous studies suggest an inverse correlation between asthma and altitude. In the present work, we performed an in-depth analysis of asthma incidence in the 758 Mexican counties covered by the largest medical institution in the country (∼37.5 million insured subjects), and evaluated its relationships with altitude and other factors. METHODS: Asthma incidence in each county was calculated from new cases diagnosed by family physicians. Other variables in the same counties, including selected diseases, geographical variables, and socioeconomic factors, were also obtained and their association with asthma was evaluated through bivariate and multivariate analyses. RESULTS: Median asthma incidence was 296.2 × 100,000 insured subjects, but tended to be higher in those counties located on or near the coast. When asthma incidence was plotted against altitude, a two-stage pattern was evident: asthma rates were relatively stable in counties located below an altitude of ∼1500 m, while these rates progressively decreased as altitude increased beyond this level (rS = -0.51, p < .001). Multivariate analysis showed that, once each variable was adjusted by the potential influence of the others, asthma incidence was inversely correlated with altitude (standardized ß coefficient, -0.577), helminthiasis (-0.173), pulmonary tuberculosis (-0.130), and latitude (-0.126), and was positively correlated with acute respiratory tract infection (0.382), pneumonia (0.289), type 2 diabetes (0.138), population (0.108), and pharyngotonsillitis (0.088), all with a p ≤ .001. CONCLUSION: Our study showed that altitude higher than ∼1500 m comprises a major factor in determining asthma incidence, with the risk of new-onset asthma decreasing as altitude increases. Other less influential conditions were also identified.

Hygiene Hypothesis in Asthma Development: Is Hygiene to Blame?

Industrialized countries have registered epidemic rates on allergic diseases, such as hay fever, asthma, eczema, and food allergies. The Hygiene Hypothesis was born from work made by Dr. David Strachan, who observed that younger siblings were less susceptible to eczema and asthma, and proposed that this was a result of increased transmission of infectious agents via unhygienic practices within a household. This initial hypothesis was then reframed as the old friends/microbiota hypothesis, implicating non-pathogenic commensal microorganisms as the source of immunomodulatory signals necessary to prevent immune-mediated chronic disorders. Although the hygiene hypothesis is supported by epidemiological research of allergic diseases in certain industrialized settings, it often fails to explain the incidence of asthma in less affluent regions of the world. In this review, we summarize up-to-date information on genetic and environmental factors associated with asthma in different human populations, and present evidence that calls for caution when associating hygiene with the pathogenesis of asthma and other allergic conditions.

Association of PM2.5 with diabetes, asthma, and high blood pressure incidence in Canada: A spatiotemporal analysis of the impacts of the energy generation and fuel sales.

Numerous studies have reported an association between fine particulate matter (PM2.5) and human health. Often these relationships are influenced by environmental factor that varies spatially and/or temporally. To our knowledge, there are no studies in Canada that have considered energy generation and fuel sales as PM2.5 effects modifiers. Determining exposure and disease-specific risk factors over space and time is crucial for disease prevention and control. In this study, we evaluated the association of PM2.5 with diabetes, asthma, and High Blood Pressure (HBP) incidence in Canada. Then we explored the impact of the energy generation and fuel sales on association changes. We fit an age-period-cohort as the study design, and we applied an over-dispersed Poisson regression model to estimate the risk. We conducted a sensitivity analysis to explore the impact of variation in clean energy rates and fuel sales on outcomes changes. The study included 117 health regions in Canada between 2007 and 2014. Our findings showed strong association of PM2.5 with diabetes, asthma, and HBP incidence. A two-year increase of 10µg/m3 in PM2.5 was associated with an increased risk of 5.34% (95% CI: 2.28%; 12.53%) in diabetes incidence, 2.24% (95% CI: 0.93%; 5.38%) in asthma incidence, and 8.29% (95% CI: 3.44%; 19.98%) in HBP incidence. Our sensitivity analysis findings suggest higher risks of diabetes, asthma and HBP incidence when there is low clean energy generation. On the other hand, we found lower risk when we considered high rate of clean energy generation. For example, considering only diabetes incidence, we found that the risk in health regions with low rates of clean electricity is approximately 700% higher than the risk in health regions with high rates of clean electricity. Furthermore, our analysis suggested that the risk in regions with low fuel sales is 66% lower than the risk is health regions with low rates of clean electricity. Our study provides support for the creation of effective environmental health public policies that take into account the risk factors present in Canadians health regions.

The global decline in asthma death rates: can we relax now?

Whilst global asthma mortality seems to be decreasing, childhood asthma incidence is rising, and early warnings from Australia show an increase in asthma-related deaths in under-15s; this article considers whether we should view the future impact of asthma with trepidation. Age-adjusted mortality statistics for asthma have been reevaluated to provide an international standard. Comparisons across regions and time are complex, yet over the last two decades asthma mortality has clearly decreased, coinciding with a significant change in asthma management. The majority of remaining asthma deaths are preventable. Nonetheless, ongoing vigilance is required. Asthma remains under-diagnosed and under-treated. Childhood asthma has become more common; it is a matter of debate whether it is also more severe. Rather than being encouraged by the fall in numbers of asthma deaths, we should focus on the surging numbers of children suffering from the disease - and the worrying increase in asthma death rates in Australian children - and work to avert future issues.