Carbon in airway macrophages and lung function in children

BACKGROUND: Epidemiologic studies indirectly suggest that the inhalation of carbonaceous particulate matter impairs lung function in children. Using the carbon content of airway macrophages as a marker of individual exposure to particulate matter derived from fossil fuel, we sought direct evidence of this association. METHODS: Airway macrophages were obtained from healthy children through sputum induction, and the area of airway macrophages occupied by carbon was measured. Lung function was measured with the use of spirometry. We modeled the exposure to primary particulate matter (PM) that is less than 10 mum in aerodynamic diameter (PM10) at or near each child's home address. Linear regression was used to evaluate associations between carbon content of alveolar macrophages and variables that may affect individual exposure. To determine whether lung function that is reduced for other reasons is associated with an increase in the carbon content of airway macrophages, we also studied children with severe asthma. RESULTS: We were able to assess the carbon content of airway macrophages in 64 of 114 healthy children (56 percent). Each increase in primary PM10 of 1.0 microg per cubic meter was associated with an increase of 0.10 microm2 (95 percent confidence interval, 0.01 to 0.18) in the carbon content of airway macrophages, and each increase of 1.0 microm2 in carbon content was associated with a reduction of 17 percent (95 percent confidence interval, 5.6 to 28.4 percent) in forced expiratory volume in one second, of 12.9 percent (95 percent confidence interval, 0.9 to 24.8 percent) in forced vital capacity, and of 34.7 percent (95 percent confidence interval, 11.3 to 58.1 percent) in the forced expiratory flow between 25 and 75 percent of the forced vital capacity. The carbon content of airway macrophages was lower in children with asthma than in healthy children. CONCLUSIONS: There is a dose-dependent inverse association between the carbon content of airway macrophages and lung function in children. We found no evidence that reduced lung function itself causes an increase in carbon content

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Corrected Figure 3 for: Oliver, J., et al. (2018). "Group A Streptococcus pharyngitis and pharyngeal carriage: A meta-analysis." PLoS Neglected Tropical Diseases 12(3): e0006335. <div><br></div><div>Note that the legend for Fig. 3B has been corrected from the version presented in the manuscript to state "Serologically confirmed GAS pharyngitis".<br><br> .<div><div></div></div></div

Group A Streptococcus pharyngitis and pharyngeal carriage: A meta-analysis

<div><p>Objective</p><p>Antibiotic treatment of Group A Streptococcus (GAS) pharyngitis is important in acute rheumatic fever (ARF) prevention, however clinical guidelines for prescription vary. GAS carriers with acute viral infections may receive antibiotics unnecessarily. This review assessed the prevalence of GAS pharyngitis and carriage in different settings.</p><p>Methods</p><p>A random-effects meta-analysis was performed. Prevalence estimates for GAS+ve pharyngitis, serologically-confirmed GAS pharyngitis and asymptomatic pharyngeal carriage were generated. Findings were stratified by age group, recruitment method and country income level. Medline and EMBASE databases were searched for relevant literature published between 1 January 1946 and 7 April 2017. Studies reporting prevalence data on GAS+ve or serologically-confirmed GAS pharyngitis that stated participants exhibited symptoms of pharyngitis or upper respiratory tract infection (URTI) were included. Included studies reporting the prevalence of asymptomatic GAS carriage needed to state participants were asymptomatic.</p><p>Results</p><p>285 eligible studies were identified. The prevalence of GAS+ve pharyngitis was 24.1% (95% CI: 22.6–25.6%) in clinical settings (which used ‘passive recruitment’ methods), but less in sore throat management programmes (which used ‘active recruitment’, 10.0%, 8.1–12.4%). GAS+ve pharyngitis was more prevalent in high-income countries (24.3%, 22.6–26.1%) compared with low/middle-income countries (17.6%, 14.9–20.7%). In clinical settings, approximately 10% of children swabbed with a sore throat have serologically-confirmed GAS pharyngitis, but this increases to around 50–60% when the child is GAS culture-positive. The prevalence of serologically-confirmed GAS pharyngitis was 10.3% (6.6–15.7%) in children from high-income countries and their asymptomatic GAS carriage prevalence was 10.5% (8.4–12.9%). A lower carriage prevalence was detected in children from low/middle income countries (5.9%, 4.3–8.1%).</p><p>Conclusions</p><p>In active sore throat management programmes, if the prevalence of GAS detection approaches the asymptomatic carriage rate (around 6–11%), there may be little benefit from antibiotic treatment as the majority of culture-positive patients are likely carriers.</p></div

Results of literature search and study selection.

<p>Results of literature search and study selection.</p

The prevalence of GAS carriage by age group, recruitment strategy and setting.

<p>The prevalence of GAS carriage by age group, recruitment strategy and setting.</p

Prevalence of GAS culture-positive pharyngitis by age group, recruitment strategy and setting.

<p>Prevalence of GAS culture-positive pharyngitis by age group, recruitment strategy and setting.</p

Total unequivocal serologically-confirmed GAS pharyngitis prevalence by age group, recruitment strategy and setting, including where GAS culture positive swabs were obtained.

<p>Total unequivocal serologically-confirmed GAS pharyngitis prevalence by age group, recruitment strategy and setting, including where GAS culture positive swabs were obtained.</p

He Kāinga Oranga: reflections on 25 years of measuring the improved health, wellbeing and sustainability of healthier housing

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