Diverging trends of respiratory allergies and eczema in Greek schoolchildren: Six surveys during 1991-2018.

Background: The prevalence of childhood asthma, rhinoconjunctivitis, and eczema in the city of Patras, Greece, has been followed in four consecutive surveys since 1991. After a continuous rise in the prevalence of all three of these disorders, a plateau was reached for asthma between 2003 and 2008, whereas the prevalence of rhinoconjunctivitis and eczema continued to increase. Objective: To investigate these trends in the same population into the following decade. Methods: We repeated two methodologically identical cross-sectional parental questionnaire surveys in 2013 and 2018 among 8-9-year-old schoolchildren (N = 2554 and N = 2648, respectively). In 2018, spirometry and fractional exhaled nitric oxide (FeNO) measurements were also performed. Results: Current asthma (i.e., wheeze/asthma in the past 2 years) decreased from 6.9% in 2008 to 5.2% in 2013 and 4.3% in 2018 (p for trend < 0.001). The prevalence of lifetime ("ever had") rhinoconjunctivitis also declined (5.1% in 2008, 4.4% in 2013, 3.0% in 2018; p for trend < 0.001), whereas that of lifetime eczema increased (10.8%, 13.6%, and 16.1%, respectively; p for trend < 0.001). The relative risk of current asthma in children with ever-had rhinoconjundtivitis was 7.73 in 2008, 6.00 in 2013, and 6.69 in 2018, whereas the relative risk in those with ever-had eczema was 5.15, 2.80, and 2.22, respectively. Among children with asthma, those with rhinoconjunctivitis had lower forced expiratory volume in the first second of expiration and higher FeNO values than those with eczema. Conclusion: The prevalence of asthma and rhinoconjunctivitis declined during the past decade in Greek schoolchildren, whereas the prevalence of eczema continued to rise. Nevertheless, the relationship between rhinoconjunctivitis and asthma remained strong, whereas the association between eczema and asthma appears to have weakened.

The Forced Oscillation Technique in Paediatric Respiratory Practice.

The Forced Oscillation Technique (FOT) is a lung function modality based on the application of an external oscillatory signal in order to determine the mechanical response of the respiratory system. The method is in principal noninvasive and requires minimal patient cooperation, which makes it suitable for use in young paediatric patients. The FOT has been successfully applied in various paediatric respiratory disorders, such as asthma, cystic fibrosis, and chronic lung disease of prematurity, in order to assess airway obstruction, bronchodilator response, and airway responsiveness after bronchoprovocation challenge. This technique may be more sensitive than spirometry in identifying disturbances of peripheral airways and assessing the level of asthma control or the effectiveness of therapy at the long term. Further research is required to determine the exact role of the FOT in paediatric lung function testing and to incorporate the method in specific diagnostic and management algorithms.

Increased ß-glucuronidase activity in bronchoalveolar lavage fluid of children with bacterial lung infection: A case-control study.

BACKGROUND AND OBJECTIVE: ß-Glucuronidase is a lysosomal enzyme released into the extracellular fluid during inflammation. Increased ß-glucuronidase activity in the cerebrospinal and peritoneal fluid has been shown to be a useful marker of bacterial inflammation. We explored the role of ß-glucuronidase in the detection of bacterial infection in bronchoalveolar lavage fluid (BALF) of paediatric patients. METHODS: In this case-control study, % polymorphonuclear cell count (PMN%), ß-glucuronidase activity, interleukin-8 (IL-8), tumour necrosis factor-α (TNF-α) and elastase were measured in culture-positive (≥10(4) cfu/mL, C+) and -negative (C-) BALF samples obtained from children. RESULTS: A total of 92 BALF samples were analysed. The median ß-glucuronidase activity (measured in nanomoles of 4-methylumbelliferone (4-MU)/mL BALF/h) was 246.4 in C+ (interquartile range: 71.2-751) and 21.9 in C- (4.0-40.8) (P < 0.001). The levels of TNF-α and IL-8 were increased in C+ as compared with C- (5.4 (1.7-12.6) vs 0.7 (0.2-6.2) pg/mL, P < 0.001 and 288 (76-4300) vs 287 (89-1566) pg/mL, P = 0.042, respectively). Elastase level and PMN% did not differ significantly (50 (21-149) vs 26 (15-59) ng/mL, P = 0.051 and 20 (9-40) vs 18 (9-34) %, P = 0.674, respectively). The area under the curve of ß-glucuronidase activity (0.856, 95% confidence interval (CI): 0.767-0.920) was higher than that of TNF-α (0.718; 95% CI: 0.614-0.806; P = 0.040), IL-8 (0.623; 95% CI: 0.516-0.722; P = 0.001), elastase (0.645; 95% CI: 0.514-0.761; P = 0.008) and PMN% (0.526; 95 % CI: 0.418-0.632; P < 0.001). CONCLUSIONS: This study demonstrates a significant increase of ß-glucuronidase activity in BALF of children with culture-positive bacterial inflammation. In our population ß-glucuronidase activity showed superior predictive ability for bacterial lung infection than other markers of inflammation.

'They said it was bronchiolitis; is it going to turn into asthma doctor?'.

Acute bronchiolitis is a common paediatric disease of infancy. Its association with subsequent asthma development has puzzled clinicians and epidemiologists for decades. This article reviews the current state of knowledge regarding the role of acute bronchiolitis in the inception of asthma. There is little doubt that acute bronchiolitis is associated with an increased risk of recurrent wheezing throughout the primary school years although the direction of causality--i.e. whether bronchiolitis in infancy leads to asthma or it merely represents the first clinical presentation of predisposition to asthma--is uncertain. Existing evidence suggests that both host factors (e.g. prematurity, atopic predisposition) and acute viral infection characteristics (e.g. type of virus, severity) are operating in this relationship, perhaps with variable involvement in different individuals. Further clarification of these issues will help paediatricians provide evidence-based information regarding the long-term prognosis of this common disease to the families, and at the same time, it will facilitate prophylactic approaches and therapeutic strategies.

Cardiopulmonary Exercise Performance of Children Born Non-Extremely Preterm.

Data on exercise tolerance of children born non-extremely preterm are sparse. We aimed to explore the cardiopulmonary exercise testing (CPET) characteristics in this population. We studied 63 children (age 7-12 years) born at 290/7-366/7 weeks of gestation (34 were late preterm, 29 were preterm) and 63 age-matched, term-born controls. All performed spirometry and CPET (cycle ergometry). There were no differences in activity levels and spirometric parameters between the group of preterm-born children and controls. A peak oxygen uptake (VO2peak) of <80% was noted in 25.4% of the term-born and 49.2% of preterm-born children (p = 0.001). Term-born participants presented similar VO2peak to late-preterm children but higher than those born at <340/7 weeks of gestation (p = 0.002). Ventilatory limitation was noted in 4.8% of term and 7.9% of preterm participants, while only one preterm child presented cardiovascular limitation. Children born before 34 weeks of gestation had higher respiratory rates and smaller tidal volumes at maximum exercise, as well as lower oxygen uptake for the level of generated work. We conclude that school-age children born at 29-34 weeks of gestation may present decreased exercise performance attributed to an altered ventilatory response to exercise and impaired O2 utilization by their skeletal muscles rather than other cardiopulmonary limiting factors.

Novel Indices to Improve the Diagnostic Ability of Nocturnal Oximetry in Children with OSAS.

Nocturnal pulse oximetry (NOx) is an alternative diagnostic test for obstructive sleep apnea syndrome (OSAS) in childhood yet with variable diagnostic performance. Our aim was to apply advanced signal analysis to develop novel and more accurate NOx indices. We studied 45 children aged 3-10 years who underwent adenotonsillectomy for adenotonsillar hypertrophy and OSAS symptoms. Participants performed NOx before and three months after surgery, and the changes in McGill oximetry score (MOS), oxygen desaturation ≥3% index (ODI3), and the novel parameters-cumulative saturation area (CSA) and oxygen saturation sample entropy (SSE)-were assessed. There was a significant improvement (p < 0.001) in all NOx indices. When pre- and post-adenotonsillectomy NOx recordings were compared, the MOS had an area under the curve (AUC) of 0.811 with 63.2% sensitivity and 100% specificity at a cutoff >1. The AUC of ODI3 was 0.994, with 97.8% sensitivity and 91.1% specificity at a cutoff of >3.6 events per hour. The CSA and SSE had an AUC of 1.00, with 100% sensitivity and specificity at a cutoff of >293 and >0.99, respectively. We conclude that the herein-introduced indices-CSA and SSE-hold promise in improving the diagnostic ability of NOx in children suspected of OSAS.

Low-frequency oscillometry indices to assess ventilation inhomogeneity in CF patients.

BACKGROUND: The utility of the forced oscillations technique (FOT) in cystic fibrosis (CF) remains uncertain. The aim of this study was to explore the ability of lower-frequency FOT indices, alone and after adjustment for the lung volume, to assess the extent of ventilation inhomogeneity in CF patients with varying disease severity. METHODS: Forty-five children, adolescents, and adults with CF (age 6.9-27 years) underwent spirometry, FOT, and nitrogen multiple-breath washout (N2-MBW) measurements. The respiratory resistance and reactance at 5 Hz (Rrs5 and Xrs5, respectively) were recorded, and a novel FOT index, the specific respiratory conductance (sGrs), was computed as the reciprocal of Rrs5 divided by the functional residual capacity. RESULTS: The sGrs correlated well with the lung clearance index (LCI) (Spearman's r: -.797), whereas the correlation of Rrs5 and Xrs5 with the LCI, albeit significant, was weaker (r: .643 and -.631, respectively). The sGrs emerged as the most robust predictor of LCI regardless of the severity of lung disease, as reflected by patients' age and lung function measurements. Most importantly, the relationship between sGrs and LCI remained unaffected by lung hyperinflation, as opposed to that of the LCI with the spirometric and standard FOT indices. CONCLUSIONS: In CF patients, the FOT indices at 5 Hz and the novel, volume-adjusted parameter sGrs, reflect the extent of lung involvement and the underlying ventilation inhomogeneity in a way comparable to N2-MBW. Future research should explore the role of lower-frequency FOT in assessing the severity and monitoring the progression of CF lung disease.

The association between leisure-time physical activities and asthma symptoms among 10- to 12-year-old children: the effect of living environment in the PANACEA study.

OBJECTIVE: This study evaluated the interrelationships of living environment, physical activity, lifestyle/dietary habits, and nutritional status on the prevalence of childhood asthma. METHODS: In a cross-sectional survey 1125 children (529 boys), 10 to 12 years old, were selected from 18 schools located in an urban environment (Athens, n = 700) and from 10 schools located in rural areas (n = 425) in Greece. RESULTS: Children living in Athens had higher likelihood of "ever had" asthma compared with children living in rural areas (odds ratio (OR) = 1.78, 95% confidence interval (CI) = 1.25-2.54), after adjusting for age and sex. After adjusting for age, sex, body mass index, and adherence to the Mediterranean diet (KIDMED score), leisure-time physical activity was inversely associated with "ever had" asthma. When stratifying by county of residence, a trend toward reduced asthma symptoms among children engaged in outdoor physical activities during their leisure time who reside in rural (but not urban) environment was observed (OR = 0.88, 95% CI = 0.77-1.01). CONCLUSIONS: The inverse relationship between asthma symptoms and leisure-time physical activity in the rural environment and the lack of an association between asthma symptoms and organized sports-related activities should draw the attention of public healthcare authorities. Their efforts should focus on the planning of a sustainable natural environment, which will promote the physical health of children and reduce the burden of childhood asthma.

Seven-days-ahead forecasting of childhood asthma admissions using artificial neural networks in Athens, Greece.

Artificial Neural Network (ANN) models were developed and applied in order to predict the total weekly number of Childhood Asthma Admission (CAA) at the greater Athens area (GAA) in Greece. Hourly meteorological data from the National Observatory of Athens and ambient air pollution data from seven different areas within the GAA for the period 2001-2004 were used. Asthma admissions for the same period were obtained from hospital registries of the three main Children's Hospitals of Athens. Three different ANN models were developed and trained in order to forecast the CAA for the subgroups of 0-4, 5-14-year olds, and for the whole study population. The results of this work have shown that ANNs could give an adequate forecast of the total weekly number of CAA in relation to the bioclimatic and air pollution conditions. The forecasted numbers are in very good agreement with the observed real total weekly numbers of CAA.

Exercise Limitation in Children and Adolescents with Mild-to-Moderate Asthma.

BACKGROUND: Children with uncontrolled asthma are less tolerant to exercise due to ventilatory limitation, exercise-induced bronchoconstriction (EIB), or physical deconditioning. The contribution of these factors in children with controlled mild-to-moderate asthma is unknown. OBJECTIVE: To explore the underlying mechanisms of reduced exercise capacity in children with controlled mild-to-moderate asthma. METHODS: This was a cross-sectional study of 45 children and adolescents (age 8-18 years) with controlled mild-to-moderate asthma (asthma control test score 21-25) and 61 age-matched healthy controls. All participants completed a physical activity questionnaire and performed spirometry and cardiopulmonary exercise testing (CPET; maximal incremental protocol). Spirometric indices and CPET parameters were compared between the two groups. The effect of EIB (FEV1 decrease >10% post CPET), ventilatory limitation and physical deconditioning on maximum oxygen uptake (O2peak), was assessed by multivariable linear regression. RESULTS: 62.2% of children with asthma and 29.5% of controls (P = 0.002) were categorized as inactive. Reduced exercise capacity (O2peak <80%) was noted in 53.3% of asthmatics and 16.4% of controls (P < 0.001). EIB was documented in 11.1% of participants with asthma. Physical deconditioning was noted in 37.8% of children with asthma and in 14.8% of controls (P = 0.013). Physical deconditioning emerged as the only significant determinant of O2peak, irrespective of asthma diagnosis, body mass index, ventilatory limitation and EIB. CONCLUSION: Children with controlled mild-to-moderate asthma are less tolerant to strenuous exercise than their healthy peers. The decreased exercise capacity in this population should mainly be attributed to physical deconditioning, while the contribution of ventilatory limitation and EIB is rather small.

Adherence to the Mediterranean type of diet is associated with lower prevalence of asthma symptoms, among 10-12 years old children: the PANACEA study.

Epidemiological studies have shown several associations between asthma symptoms and dietary factors. The aim of this work was to evaluate the relationship between adherence to the Mediterranean diet and childhood asthma. A cross-sectional analysis was performed on 700 children (323 boys), 10-12 yr old, selected from 18 schools located in Athens greater area. Children and their parents completed questionnaires, which evaluated, among others, dietary habits. Asthma was defined according to ISAAC II criteria. Adherence to the Mediterranean diet was evaluated using the KIDMED score (theoretical range 0-12). Higher KIDMED score corresponds to greater adherence to the Mediterranean diet. Greater adherence to the Mediterranean diet was inversely associated with ever had wheeze (p = 0.001), exercise wheeze (p = 0.004), ever had diagnosed asthma (p = 0.002) and with any asthma symptoms (p < 0.001). One-unit increase in the KIDMED score was associated with 14% lower likelihood of having asthma symptoms (odds ratio = 0.86, 95% confidence interval 0.75-0.98), after adjusting for various confounders. No significant associations were found between asthma symptoms and consumption of fruits (p = 0.25), vegetables (p = 0.97), legumes (p = 0.76), cereals (p = 0.71), dairy (p = 0.61), salty snacks (p = 0.53), or margarine/butter (p = 0.42) consumption, while increased fish and meat intake was associated with less asthma symptoms (p = 0.04 and p = 0.01, respectively). Our findings suggest an inverse relationship between level of adherence to the Mediterranean diet and prevalence of asthma in school-aged children.

Sex-specific trends in prevalence of childhood asthma over 30 years in Patras, Greece.

AIM: According to four surveys conducted during 1978-2003, the prevalence of childhood asthma and wheezing has risen in the city of Patras, Greece, albeit at a decelerating rate. We examined sex-specific wheeze and asthma prevalence in the same urban environment in 2008. METHODS: A cross-sectional parental questionnaire survey was performed in 2008 among third and fourth grade schoolchildren (8-9 year old), which was identical to previously conducted surveys in 1978 (n = 3003), 1991 (n = 2417), 1998 (n = 3076) and 2003 (n = 2725). RESULTS: The prevalence of current wheeze and asthma in 1978, 1991, 1998, 2003 and 2008 (n = 2688) was 1.5%, 4.6%, 6.0%, 6.9% and 6.9%, respectively (p for trend <0.001). Respective values for lifetime (ever had) wheeze and asthma in the 1991-2008 surveys were 8.0%, 9.6%, 12.4% and 12.6% (p for trend <0.001). The male:female ratio of current and lifetime wheeze and asthma increased during the 30-year surveillance period (p for trend <0.001). Irrespective of sex, diagnosed asthma declined among current wheezers by 17% (p < 0.001), but not among non-current ones (6.7%, p = 0.16) during 2003-2008. CONCLUSIONS: Childhood wheeze and asthma have reached a plateau in an urban environment in Greece, while the male:female ratio increased. Asthma diagnosis declined among schoolage but not preschool wheezers during 2003-2008.

Prevalence trends of rhinoconjunctivitis, eczema, and atopic asthma in Greek schoolchildren: four surveys during 1991-2008.

After a continuous increase of asthma, hay fever, and eczema during 1991-2003 among schoolchildren in Patras, Greece, the prevalence of current wheeze/asthma (diagnosed wheezing and/or asthma in the past 2 years) has reached a plateau (6.9%) during the period 2004-2008. Using methodology identical to the three previously conducted cross-sectional, parental questionnaire surveys (1991, n = 2417; 1998, n = 3076; 2003, n = 2725) we examined further trends in the prevalence of rhinoconjunctivitis and eczema in the same urban environment among third and fourth grade schoolchildren (8-9 years old) in 2008 (n = 2688). In the four surveys, respective prevalence rates of rhinoconjunctivitis were 2.1, 3.4, 4.6, and 5.1% (absolute prevalence increase: 1998 versus 1991, 61.9%; 2003 versus 1998, 35.5%; 2008 versus 2003, 10.9%) and those of eczema were 4.5, 6.3, 9.5, and 10.8% (absolute prevalence increase: 1998 versus 1991, 40.0%; 2003 versus 1998, 50.8%; 2008 versus 2003, 13.7%; sex-adjusted p for trend, <0.001). Among current wheezer/asthmatic patients there was an increase in lifetime rhinoconjunctivitis (sex-adjusted p for trend, <0.001) and lifetime eczema (sex-adjusted p for tend, <0.001) over the period 1991-2008. The proportion of atopic wheeze/asthma (current asthma with lifetime rhinoconjunctivitis and/or eczema) increased further during 2003-2008 (p < 0.05; p for trend during 1991-2008, <0.001). In conclusion, there is a continuous increase in the prevalence of allergic manifestations-rhinoconjunctivitis and eczema-among preadolescent children in Patras, Greece, during the period 1991-2008. After a steep rise during 1991-2003, the frequency of atopic wheeze/asthma continued to increase at a decelerating rate during 2003-2008, while wheeze/asthma prevalence remained unchanged during the same 5-year period.

Urban environment adherence to the Mediterranean diet and prevalence of asthma symptoms among 10- to 12-year-old children: The Physical Activity, Nutrition, and Allergies in Children Examined in Athens study.

Epidemiological studies have revealed several associations between asthma symptoms and environmental and dietary factors, but the potential environment- diet interactions on asthma incidence have rarely been investigated. The aim of this work was to evaluate the interrelationships between urban/rural environment, adherence to a healthy dietary pattern, the Mediterranean diet, and childhood asthma. A cross-sectional survey was performed and 1125 (529 boys), 10- to 12-year-old children were selected from 18 schools located in urban Athens area (n = 700) and from 10 schools located in rural areas of Ilia and Viotia (n = 425), Greece. Children and their parents completed standardized questionnaires, which evaluated, among others, environmental factors and dietary habits. Asthma was defined according to Phase II of the International Study on Allergies and Asthma in Childhood criteria. Adherence to the Mediterranean diet was assessed using the Mediterranean and Diet Quality Index for children and adolescents (KIDMED) score. Living in urban areas was associated with higher odds of ever had asthma symptoms by 1.78 times (95% confidence interval [CI], 1.25-2.54) when compared with rural areas. In contrast, 1-unit increase in the KIDMED score was associated with 16% lower likelihood of having asthma symptoms (95% CI, 0.77-0.91), after adjusting for various confounders. When stratifying the analysis by area of living it was observed that adherence to the Mediterranean diet was associated with lower likelihood of asthma in both urban and rural areas (urban, odds ratio [OR] = 0.81, 95% CI, 0.73-0.91; rural, OR = 0.87, 95% CI, 0.75-1.00). Urban environment seems to increase the likelihood of childhood asthma, whereas adherence to the healthy Mediterranean dietary pattern could mediate the aforementioned association and confers significant protection.

Molecular surveillance of pneumococcal carriage following completion of immunization with the 13-valent pneumococcal conjugate vaccine administered in a 3 + 1 schedule.

In a cross-sectional study, with the use of molecular methods, we aimed to gain insight into oropharyngeal pneumococcal colonization over time in 1212 Greek children recruited in general pediatric settings throughout the country; they were fully vaccinated with PCV13 (3 + 1 schedule). A single sample was obtained from each child at a time interval of 26 days to 70 months after administration of the 4th (booster) PCV13 dose; sampling time was divided into six time intervals. Carriage of Streptococcus pneumoniae was detected by real-time PCR targeting the lytA gene and isolates were serotyped by singleplex real-time PCR assays. Multiple control procedures to avoid false-positive results were applied. We showed an overall S. pneumoniae carriage rate of 48.6%. Serotyping identified typeable isolates in 82% of the total lytA-positive samples. Non-PCV13 serotypes represented 83.8% of total isolates when excluding serogroups with mixed PCV13 and non-PCV13 serotypes. In multivariate analysis daycare/school attendance emerged as the main contributing factor. Notably, serotypes 19A and 3 were the only two PCV13 serotypes the colonization rate of which increased over time (χ2 for trend P < 0.001 and P = 0.012, respectively). The application of the SP2020 gene on lytA-positive serotyped samples showed pneumococcal colonization in 97% of cases, and the overall colonization profile over time closely resembled that of the lytA gene. With the provisions of the methodological approach and age group of our study, the use of the oropharynx emerges as a reliable alternative to the nasopharynx in estimating pneumococcal carriage in epidemiological studies.

Pediatric Pulmonary Function Testing in COVID-19 Pandemic and Beyond. A Position Statement From the Hellenic Pediatric Respiratory Society.

As the COVID-19 pandemic is still evolving, guidelines on pulmonary function testing that may dynamically adapt to sudden epidemiologic changes are required. This paper presents the recommendations of the Hellenic Pediatric Respiratory Society (HPRS) on pulmonary function testing in children and adolescents during the COVID-19 era. Following an extensive review of the relevant literature, we recommend that pulmonary function tests should be carried out after careful evaluation of the epidemiologic load, structured clinical screening of all candidates, and application of special protective measures to minimize the risk of viral cross infection. These principles have been integrated into a dynamic action plan that may readily adapt to the phase of the pandemic.

Changing trends in the prevalence of childhood asthma over 40 years in Greece.

BACKGROUND: A series of repeated questionnaire surveys among 8- to 9-year-old school children in the city of Patras, Greece, demonstrated a continuous rise in the prevalence of wheeze/asthma from 1978 to 2003, with a plateau between 2003 and 2008. We further investigated wheeze/asthma trends within the same environment over the last decade. METHODS: Two follow-up surveys were conducted in 2013 (N = 2554) and 2018 (N = 2648). Physician-diagnosed wheeze and asthma were analyzed in relation to their occurrence (recent-onset: within the last 2 years; noncurrent: before 2 years; persistent: both prior and within the last 2 years). In 2018, spirometry was also performed in participants reporting symptoms and in a sample of healthy controls. RESULTS: The prevalence of current wheeze/asthma declined from 6.9% in 2008% to 5.2% in 2013% and 4.3% in 2018. The persistent and noncurrent wheeze/asthma groups followed this overall trend (P-for-trend <0.001), while the prevalence of recent-onset wheeze/asthma remained unchanged (P-for-trend >0.05). Persistent and noncurrent wheezers were also more frequently diagnosed with asthma, in contrast to those with recent-onset wheeze. The FEV1 z-score was less than -1 in 32.1% of children with recent-onset and in 22.4% of those with persistent wheeze/asthma; both rates were higher than those of the Noncurrent wheeze/asthma group (7.1%; p < .05) and of healthy controls (3.5%; p < .001). CONCLUSIONS: The prevalence of childhood wheeze/asthma has declined significantly during the last decade in Greece. The reversing trend may in part be attributed to changing asthma perceptions among physicians and/or parents, especially in the case of younger children with troublesome respiratory symptoms.

Outdoor particulate matter and childhood asthma admissions in Athens, Greece: a time-series study.

BACKGROUND: Particulate matter with diameter less than 10 micrometers (PM10) that originates from anthropogenic activities and natural sources may settle in the bronchi and cause adverse effects possibly via oxidative stress in susceptible individuals, such as asthmatic children. This study aimed to investigate the effect of outdoor PM10 concentrations on childhood asthma admissions (CAA) in Athens, Greece. METHODS: Daily counts of CAA from the three Children's Hospitals within the greater Athens' area were obtained from the hospital records during a four-year period (2001-2004, n = 3602 children). Mean daily PM10 concentrations recorded by the air pollution-monitoring network of the greater Athens area were also collected. The relationship between CAA and PM10 concentrations was investigated using the Generalized Linear Models with Poisson distribution and logistic analysis. RESULTS: There was a statistically significant (95% CL) relationship between CAA and mean daily PM10 concentrations on the day of exposure (+3.8% for 10 microg/m3 increase in PM10 concentrations), while a 1-day lag (+3.4% for 10 microg/m3 increase in PM10 concentrations) and a 4-day lag (+4.3% for 10 microg/m3 increase in PM10 concentrations) were observed for older asthmatic children (5-14 year-old). High mean daily PM10 concentration (the highest 10%; >65.69 microg/m3) doubled the risk of asthma exacerbations even in younger asthmatic children (0-4 year-old). CONCLUSIONS: Our results provide evidence of the adverse effect of PM10 on the rates of paediatric asthma exacerbations and hospital admissions. A four-day lag effect between PM10 peak exposure and asthma admissions was also observed in the older age group.

Asthma: A Loss of Post-natal Homeostatic Control of Airways Smooth Muscle With Regression Toward a Pre-natal State.

The defining feature of asthma is loss of normal post-natal homeostatic control of airways smooth muscle (ASM). This is the key feature that distinguishes asthma from all other forms of respiratory disease. Failure to focus on impaired ASM homeostasis largely explains our failure to find a cure and contributes to the widespread excessive morbidity associated with the condition despite the presence of effective therapies. The mechanisms responsible for destabilizing the normal tight control of ASM and hence airways caliber in post-natal life are unknown but it is clear that atopic inflammation is neither necessary nor sufficient. Loss of homeostasis results in excessive ASM contraction which, in those with poor control, is manifest by variations in airflow resistance over short periods of time. During viral exacerbations, the ability to respond to bronchodilators is partially or almost completely lost, resulting in ASM being "locked down" in a contracted state. Corticosteroids appear to restore normal or near normal homeostasis in those with poor control and restore bronchodilator responsiveness during exacerbations. The mechanism of action of corticosteroids is unknown and the assumption that their action is solely due to "anti-inflammatory" effects needs to be challenged. ASM, in evolutionary terms, dates to the earliest land dwelling creatures that required muscle to empty primitive lungs. ASM appears very early in embryonic development and active peristalsis is essential for the formation of the lungs. However, in post-natal life its only role appears to be to maintain airways in a configuration that minimizes resistance to airflow and dead space. In health, significant constriction is actively prevented, presumably through classic negative feedback loops. Disruption of this robust homeostatic control can develop at any age and results in asthma. In order to develop a cure, we need to move from our current focus on immunology and inflammatory pathways to work that will lead to an understanding of the mechanisms that contribute to ASM stability in health and how this is disrupted to cause asthma. This requires a radical change in the focus of most of "asthma research."