Air pollution and anemia as risk factors for pneumonia in Ecuadorian children: a retrospective cohort analysis

The Impact of Malnutrition on the Developing Lung and Long-Term Lung Health: A Narrative Review of Global Literature

Worldwide, over 2 billion children under the age of 5 experience stunting, wasting, or are underweight. Malnutrition contributes to 45% of all deaths in this age group (approximately 3.1 million deaths) [1]. Poverty, food insecurity, suboptimal feeding practices, climate change, and conflict are all contributing factors. Malnutrition causes significant respiratory problems, including increased risk of respiratory infections, impaired lung function, and increased risk of subsequent adult respiratory disease, including asthma, COPD, and lung cancer. Childhood malnutrition not only has serious consequences for children's health but it also has numerous consequences on wellbeing and educational attainment. Childhood malnutrition is a complex and multifaceted problem. However, by understanding and addressing the underlying causes, and investing in prevention and treatment programs, it is possible to maximize children's health and wellbeing on a global scale. This narrative review will focus on the impact of childhood malnutrition on lung development, the consequent respiratory disease, and what actions can be taken to reduce the burden of malnutrition on lung health.

A cross-sectional analysis of ambient fine particulate matter (PM2.5) exposure and haemoglobin levels in children aged under 5 years living in 36 countries

Low haemoglobin (Hb) concentrations and anaemia in children have adverse effects on development and functioning, some of which may have consequences in later life. Exposure to ambient air pollution is reported to be associated with anaemia, but there is little evidence specific to low- and middle-income countries (LMICs), where childhood anaemia prevalence is greatest. We aimed to determine if long-term ambient fine particulate matter (≤2.5 μm in aerodynamic diameter [PM_2.5]) exposure was associated with Hb levels and the prevalence of anaemia in children aged <5 years living in 36 LMICs. We used Demographic and Health Survey data, collected between 2010 and 2019, which included blood Hb measurements. Satellite-derived estimates of annual average PM_2.5 was the main exposure variable, which was linked to children's area of residence. Anaemia was defined according to standard World Health Organization guidelines (Hb < 11 g/dL). The association of PM_2.5 with Hb levels and anaemia prevalence was examined using multivariable linear and logistic regression models, respectively. We examined whether the effects of ambient PM_2.5 were modified by a child's sex and age, household wealth index, and urban/rural place of residence. Models were adjusted for relevant covariates, including other outdoor pollutants and household cooking fuel. The study included 154,443 children, of which 89,904 (58.2%) were anaemic. The country-level prevalence of anaemia ranged from 15.8% to 87.9%. Mean PM_2.5 exposure was 33.0 (±21.6) μg/m³. The adjusted model showed that a 10 μg/m³ increase in annual PM_2.5 concentration was associated with greater odds of anaemia (OR = 1.098 95% CI: 1.087, 1.109). The same increase in PM_2.5 was associated with a decrease in average Hb levels of 0.075 g/dL (95% CI: 0.081, 0.068). There was evidence of effect modification by household wealth index and place of residence, with greater adverse effects in children from lower wealth quintiles and children in rural areas. Exposure to annual PM_2.5 was cross-sectionally associated with decreased blood Hb levels, and greater risk of anaemia, in children aged <5 years living in 36 LMICs.

Prenatal Exposure to Air Pollution and Pre-Labor Rupture of Membranes in a Prospective Cohort Study: The Role of Maternal Hemoglobin and Iron Supplementation

BACKGROUND

Exposure to air pollution in prenatal period is associated with prelabor rupture of membranes (PROM). However, the sensitive exposure time windows and the possible biological mechanisms underlying this association remain unclear.

OBJECTIVE

We aimed to identify the sensitive time windows of exposure to air pollution for PROM risk. Further, we examined whether maternal hemoglobin levels mediate the association between exposure to air pollution and PROM, as well as investigated the potential effect of iron supplementation on this association.

METHOD

From 2015 to 2021, 6,824 mother-newborn pairs were enrolled in the study from three hospitals in Hefei, China. We obtained air pollutant data [particulate matter (PM) with aerodynamic diameter ≤2.5μm (PM2.5), PM with aerodynamic diameter ≤10μm (PM10), sulfur dioxide (SO2), and carbon monoxide (CO)] from the Hefei City Ecology and Environment Bureau. Information on maternal hemoglobin levels, gestational anemia, iron supplementation, and PROM was obtained from medical records. Logistic regression models with distributed lags were used to identify the sensitive time window for the effect of prenatal exposure to air pollutant on PROM. Mediation analysis estimated the mediated effect of maternal hemoglobin in the third trimester, linking prenatal air pollution with PROM. Stratified analysis was used to investigate the potential effect of iron supplementation on PROM risk.

RESULTS

We found significant association between prenatal exposure to air pollution and increased PROM risk after adjusting for confounders, and the critical exposure windows of PM2.5, PM10, SO2 and CO were the 21th to 24th weeks of pregnancy. Every 10-μg/m3 increase in PM2.5 and PM10, 5-μg/m3 increase in SO2, and 0.1-mg/m3 increase in CO was associated with low maternal hemoglobin levels [-0.94g/L (95% confidence interval (CI): -1.15, -0.73), -1.31g/L (95% CI: -1.55, -1.07), -2.96g/L (95% CI: -3.32, -2.61), and -1.11g/L (95% CI: -1.31, -0.92), respectively] in the third trimester. The proportion of the association between air pollution and PROM risk mediated by hemoglobin levels was 20.61% [average mediation effect (95% CI): 0.02 (0.01, 0.05); average direct effect (95%): 0.08 (0.02, 0.14)]. The PROM risk associated with exposure to low-medium air pollution could be attenuated by maternal iron supplementation in women with gestational anemia.

CONCLUSIONS

Prenatal exposure to air pollution, especially in the 21st to 24th weeks of pregnancy, is associated with PROM risk, which is partly mediated by maternal hemoglobin levels. Iron supplementation in anemia pregnancies may have protective effects against PROM risk associated with exposure to low-medium air pollution. https://doi.org/10.1289/EHP11134.

Effects of wildfire smoke PM2.5 on indicators of inflammation, health, and metabolism of preweaned Holstein heifers

Wildfires are a growing concern as large, catastrophic fires are becoming more commonplace. Wildfire smoke consists of fine particulate matter (PM2.5), which can cause immune responses and disease in humans. However, the present knowledge of the effects of wildfire PM2.5 on dairy cattle is sparse. The present study aimed to elucidate the effects of wildfire-PM2.5 exposure on dairy calf health and performance. Preweaned Holstein heifers (N = 15) were assessed from birth through weaning, coinciding with the 2021 wildfire season. Respiratory rate, heart rate, rectal temperatures, and health scores were recorded and blood samples were collected weekly or twice a week for analysis of hematology, blood metabolites, and acute phase proteins. Hourly PM2.5 concentrations and meteorological data were obtained, and temperature-humidity index (THI) was calculated. Contribution of wildfires to PM2.5 fluxes were determined utilizing AirNowTech Navigator and HYSPLIT modeling. Mixed models were used for data analysis, with separate models for lags of up to 7 d, and fixed effects of daily average PM2.5, THI, and PM2.5 × THI, and calf as a random effect. THI ranged from 48 to 73, while PM2.5 reached concentrations up to 118.8 µg/m3 during active wildfires. PM2.5 and THI positively interacted to elevate respiratory rate, heart rate, rectal temperature, and eosinophils on lag day 0 (day of exposure; all P < 0.05). There was a negative interactive effect of PM2.5 and THI on lymphocytes after a 2-d lag (P = 0.03), and total white blood cells, neutrophils, hemoglobin, and hematocrit after a 3-d lag (all P < 0.02), whereas there was a positive interactive effect on cough scores and eye scores on lag day 3 (all P < 0.02). Glucose and NEFA were increased as a result of combined elevated PM2.5 and THI on lag day 1, whereas BHB was decreased (all P < 0.05). Contrarily, on lag day 3 and 6, there was a negative interactive effect of PM2.5 and THI on glucose and NEFA, but a positive interactive effect on BHB (all P < 0.03). Serum amyloid A was decreased whereas haptoglobin was increased with elevated PM2.5 and THI together on lag days 0 to 4 (all P < 0.05). These findings indicate that exposure to wildfire-derived PM2.5, along with increased THI during the summer months, elicits negative effects on preweaned calf health and performance both during and following exposure.

Childhood Anemia and Risk for Acute Respiratory Infection, Gastroenteritis, and Urinary Tract Infection: A Systematic Review

Objective Children younger than 5 years, particularly children below 2 years, are among the most vulnerable groups for developing anemia and infections. This review is intended to assess the association between anemia and childhood acute respiratory infections (ARTIs), acute gastroenteritis (AGE), and urinary tract infections (UTIs).

Methods PubMed was searched for published articles from January 2000 to August 2021 in English using the following terms: anemia and acute respiratory tract infections in children; anemia and UTIs in children; anemia and AGE in children. The data extraction were conducted by two investigators using the same methodology. Using descriptive statistics, the data from different sources were synthesized, including medians and ranges.

Results A total of 426 articles and 27 original articles and 1 systematic review were included. Iron deficiency anemia is common among children between 6 months and 3 years of age. This age group can be considered a highly susceptible age for contraction of ARTI and AGE. Children below 5 years suffer five to six episodes of acute ARTI per year on average, and pneumonia accounts for the highest number of deaths, which is around 1.1 million each year. When considered, the odds ratio of anemia to increase the susceptibility of contracting lower ARTI would range from 2 to 5.7. Also, anemic children were 10 times more susceptible to developing acute recurrent ARTI and 4 times more susceptible to contracting pneumonia. Respiratory syncytial virus is the commonest viral etiology. Anemia would increase the risk of diarrhea by 2.9-fold in toddlers, while mild anemia, moderate anemia, and severe anemia would increase the susceptibility to contract AGE by 1.6, 1.6, and 8.9 times, respectively. Rotavirus is the commonest etiology. Some studies observed a protective effect of mild to moderate iron-deficient anemia from respiratory infections.

Conclusion Infectious disease imposes a heavy burden on the health sector in a country. The highest susceptibility for infections and the development of anemia would be due to inadequate nutrition supplementation to meet the demand during rapid body growth. Therefore, based on the available evidence, one can take the necessary steps to reduce the infectious disease burden by correcting the anemia status in children.

Hereditary spherocytosis before and after splenectomy and risk of hospitalization for infection

BACKGROUND

The infectious burden in hereditary spherocytosis (HS) children before splenectomy has rarely been reported and the risk of severe postsplenectomy infection is controversial.

METHODS

We conducted a retrospective study of pediatric patients with HS to evaluate the risk of infection presplenectomy and postsplenectomy. The primary outcome was any bacterial, Mycoplasma, or fungal infection that required hospitalization. The secondary outcomes were sepsis and septic shock. Appendectomized children were matched on age at surgery and enrolled as controls.

RESULTS

In all, 232 patients were included. Before splenectomy, the primary outcome was identified in 51 (22.0%) patients, and the secondary outcome was identified in 1 (0.4%) patient. After splenectomy, the primary and secondary outcomes were detected in 8 (4.1%) and 1 (0.5%) patients, respectively. The risk of infection was higher presplenectomy than postsplenectomy (OR, 6.6; 95% CI, 3.0-14.2). HS patients had a higher risk of infection than the controls before surgery (OR, 3.7; 95% CI, 2.3-5.9) but not after surgery (OR, 1.4; 95% CI, 0.6-3.6).

CONCLUSIONS

HS patients who require splenectomy later in life had a high incidence of hospitalization for infections. In contrast, postsplenectomy risk of hospitalization involving infection or severe infection was low.

IMPACT

Patients with hereditary spherocytosis who require splenectomy later in life have a high risk of hospital admission for infections, especially those with severe hereditary spherocytosis. With vaccines or postoperative antibiotics, splenectomy does not increase the risk of infection or severe infections. Splenectomy may reduce the risk of hospitalization for infections by alleviating the complications of hereditary spherocytosis. With vaccines, prophylaxis, or advanced antibiotics, the benefits of splenectomy in children with hereditary spherocytosis and a heavy disease burden may outweigh the risks.

Direct and Indirect Effects of Indoor Particulate Matter on Blood Indicators Related to Anemia

Exposure to indoor particulate matter (PM) is a potential risk factor that increases systemic inflammation and affects erythropoiesis. This study investigated the association between exposure to indoor PM and blood indicators related to anemia (BIRA) in housewives. Indoor PM and blood folate status are important factors in the risk of anemia. This was a housewife cohort study; we recruited 284 housewives in Seoul and Ulsan, Republic of Korea. Indoor exposure to PM2.5 and PM10 was measured by gravimetric analysis and sensors. We investigated the BIRA, such as hemoglobin (Hb), hematocrit, mean corpuscular volume (MCV), mean corpuscular Hb (MCH), and mean corpuscular Hb concentration (MCHC). Statistical analysis was performed by multiple linear regression model and mediation analysis. The association between BIRA and PM was assessed by multiple linear regression models fitted by mediation analyses. The increase in the level of indoor PM2.5 was associated with a decrease in MCV (Beta coefficient (B): −0.069, Standard error (SE): 0.022) and MCH (B: −0.019, SE: 0.009) in gravimetric measurements. The increase in the level of indoor PM2.5 was associated with a decrease in Hb (B: −0.024, SE: 0.011), hematocrit (B: −0.059, SE: 0.033), and MCV (B: −0.081, SE: 0.037) and MCH (B: −0.037, SE: 0.012) in sensor measurements (PM2.5-Lag10). Further, we identified a serum folate-mediated PM effect. The indoor PM exposure was significantly associated with decreased Hb, MCV, and MCH in housewives. Taken together, our data show that exposure to indoor PM is a risk factor for anemia in housewives. Blood folate concentration can be a mediating factor in the effect of indoor PM on BIRA. Therefore, folate intake should be recommended to prevent anemia in housewives. Moreover, indoor PM exposure should be managed.

Preconceptional and prenatal exposure to air pollution increases incidence of childhood pneumonia: A hypothesis of the (pre-)fetal origin of childhood pneumonia

BACKGROUND

Increasing evidence has linked childhood pneumonia with early exposure to ambient air pollution. However, the impact of exposure to air pollutants before birth is unclear.

OBJECTIVE

To further clarify whether exposure to a particular pollutant during preconceptional and prenatal periods, may pose a higher risk of developing childhood pneumonia.

METHODS

This case-control cohort study consisted of 1510 children aged 0-14 years in Changsha, China between 2017 and 2019. Data of children's history of pneumonia and blood biomarkers were obtained from the XiangYa Hospital records. Each child's exposure to air pollutants, including nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and particulate matter with an aerodynamic diameter ≤ 10 µm (PM₁₀), was calculated using data from ten air pollution monitoring stations. A multivariate logistic regression model was used to quantify the relationship between childhood pneumonia and exposure to ambient air pollution during the preconceptional and prenatal periods.

RESULTS

Childhood pneumonia was significantly associated with preconceptional and prenatal exposure to the industrial-related air pollutant, SO₂, for 1 year before conception, for 3 months before conception and for the entire pregnancy, with ORs(95% CI)= 4.01(3.17-5.07), 4.06(3.29-5.00) and 6.51(4.82-8.79). Also, children who were sick with pneumonia had higher white blood cell and neutrophil counts, and children with low eosinophil count or hemoglobin are likely to get pneumonia. Sensitivity analysis showed that boys, and children in high temperature area were susceptible to the effect of both preconceptional and prenatal exposure to industrial SO₂.

CONCLUSION

Preconceptional and prenatal exposure to industrial-related air pollution plays a significant role in the incidence and progression of childhood pneumonia, supporting the hypothesis of "(pre-)fetal origin of childhood pneumonia".

Does underweight amplify the relationship between short-term particulate matter exposure and blood pressure in children and adolescents: a large cross-sectional study in a metropolis of China

Overweight/obesity modified the effects of ambient particulate matter (PM) exposure on blood pressure (BP). This study aims to assess whether interaction of underweight and short-term PM exposure on BP exists in Chinese children. A cross-sectional analysis including 144,513 children aged 6 to 17 years in 2016 Health Promotion Program for Children and Adolescents of Suzhou, China, was performed. Daily concentrations of inhalable PM (PM₁₀) and fine PM (PM_2.5) were extracted from air monitoring stations close to students' schools. We applied generalized linear mixed-effects models to estimate the interactions. Estimated changes (95% confidence intervals (CIs)) of systolic BP (SBP), diastolic BP (DBP), and odds ratios (ORs) (95% CIs) for prevalence of HBP were calculated. Significant interactions between PM and underweight on BP and prevalence of high BP (HBP) were observed. For example, at lag 6, the ORs (95% CIs) for HBP by each 10 μg/m³ changes of PM_2.5 were 1.066 (1.039, 1.093) and 1.036 (1.028, 1.043) among underweight and normal weight subjects, respectively; these values for PM₁₀ were 1.048 (1.031, 1.065) and 1.025 (1.021, 1.030). At lag 5, the increases of SBP for PM_2.5 were 0.32 (95% CI 0.22, 0.43) mmHg and 0.23 (95% CI 0.29, 0.26) mmHg, while changes of DBP were 0.27 (95% CI 0.18, 0.35) mmHg and 0.19 (95% CI 0.16, 0.21) mmHg among underweight and normal weight subjects, respectively. Stratified analyses demonstrated that these interactions were only obtained in males. Effects of short-term PM exposure on BP and prevalence of HBP are enhanced in underweight children and adolescents.

Seasonal variations in PM10 inorganic composition in the Andean city

Particulate matter (PM) is one of the key pollutants causing health risks worldwide. While the preoccupation for increased concentrations of these particles mainly depends on their sources and thus chemical composition, some regions are yet not well investigated. In this work the composition of chemical elements of atmospheric PM₁₀ (particles with aerodynamic diameters ≤ 10 µm), collected at the urban and suburban sites in high elevation tropical city, were chemically analysed during the dry and wet seasons of 2017-2018. A large fraction (~ 68%) of PM₁₀ composition in Quito, Ecuador is accounted for by water-soluble ions and 16 elements analysed using UV/VIS spectrophotometer and Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). Hierarchical clustering analysis was performed to study a correlation between the chemical composition of urban pollution and meteorological parameters. The suburban area displays an increase in PM₁₀ concentrations and natural elemental markers during the dry (increased wind intensity, resuspension of soil dust) season. Meanwhile, densely urbanized area shows increased total PM₁₀ concentrations and anthropogenic elemental markers during the wet season, which may point to the worsened combustion and traffic conditions. This might indicate the prevalence of cardiovascular and respiratory problems in motorized areas of the cities in the developing world.

Cribra orbitalia and porotic hyperostosis are associated with respiratory infections in a contemporary mortality sample from New Mexico

OBJECTIVES

Cribra orbitalia (CO) and porotic hyperostosis (PH) are porous cranial lesions (PCLs) classically associated with iron-deficiency anemia in bioarchaeological contexts. However, recent studies indicate a need to reassess the interpretation of PCLs. This study addresses the potential health correlates of PCLs in a contemporary sample by examining relationships between the known cause of death (COD) and PCL presence/absence.

METHODS

This study includes a sample of 461 juvenile individuals (6 months to 15 years of age) who underwent examination at the University of New Mexico's Office of the Medical Investigator between 2011 and 2019. The information available for each individual includes their sex, age at death, and their COD and manner of death.

RESULTS

Odds ratio of having CO (OR = 3.92, p < .01) or PH (OR = 2.86, p = .02) lesions are increased in individuals with respiratory infections. Individuals with heart conditions have increased odds of having CO (OR = 3.52, p = .03) lesions, but not PH.

CONCLUSION

Individuals with respiratory infection are more likely to have CO and/or PH. CO appears to have a greater range of health correlates than PH does, as indicated by the heart condition results. However, individuals with congenital heart defects are at higher risk for respiratory infections, so bony alterations in cases of heart conditions may be due to respiratory illness. Since respiratory infection remains a leading cause of mortality today, CO and PH in bioarchaeological contexts should be considered as potential indicators of respiratory infections in the past.

Acute respiratory symptoms and its associated factors among mothers who have under five-years-old children in northwest, Ethiopia

Background

Poor air quality of the household is likely to be the largest public health concern in resource-constrained countries. Exposure to household air pollution, poor working environment, and fuel type used at household level have been associated with respiratory symptoms. This study aimed to assess acute respiratory symptoms and its associated factors among mothers who have under five-years-old children in Gondar city, northwest Ethiopia.

Method

A cross-sectional study was carried out from February 15, 2019 to June 20, 2019. Study participants were selected using simple random sampling, and data were collected via face-to-face interviews. Binary logistic regression analysis was used to test the association of explanatory and outcome variables. Variables with p < 0.05 were considered as significantly associated with the outcome variable.

Results

The prevalence of respiratory symptoms among mothers of under-five years-old children in this study was 46.1%. Education (vocational training compared to cannot read and write) (adjusted odd ratio (AOR) = 0.26 at 95% confidence interval (CI): 0.08–0.82), working in dusty environment (AOR = 2.90 at 95% CI: 1.39–6.08), wood fire use (AOR = 0.37 at 95% CI: 0.16–0.85), living in mud- and wood-walled houses (AOR = 0.53 at CI: 0.32–0.89), recent house painting (AOR = 1.95 at 95% CI: 1.03–3.69), new carpet (AOR = 2.02 at 95% CI: 1.08–3.77), pesticide use (AOR = 1.71 at 95% CI: 1.03–2.84), damp stain (AOR = 2.45 at 95% CI: 1.04–5.75), spending longer time in house for 6 to 11 h (AOR = 2.59 at 95% CI: 1.53–4.37) and 11 to 15 h (AOR = 3.47 at 95% CI: 1.87–6.43), and living less than 100 m from unpaved roads/streets (AOR = 4.35 at 95% CI: 2.64–7.18) were significantly associated with respiratory symptoms among mothers of under-five years-old children.

Conclusion

Respiratory symptoms were common among mothers who have under five-years-old children. Air quality improvement, fuel selection, and residential planning will help to reduce respiratory symptoms.

Pneumonia among Under-Five Children in Northwest Ethiopia: Prevalence and Predictors-A Community-Based Cross-Sectional Study

Background

Acute respiratory infections in particular pneumonia constitutes the leading cause of morbidity and mortality among children under five years of age throughout the world. In Ethiopia, pneumonia continues to be the major childhood problem and killer, particularly in the study area. However, evidence dealing with the problem is still unavailable. The current study is aimed at determining the magnitude and risk factors of childhood pneumonia in Gondar City.

Methods

A community-based cross-sectional study was employed in five randomly selected clusters/subcities of Gondar City. A total of 792 child-mother/caregiver pairs in the selected subcities/clusters were included. A pretested and validated questionnaire was used by trained supervisors through house-to-house visits to collect the data. Binary logistic regression (bivariable and multivariable) was employed. An adjusted odds ratio with 95% confidence interval was used to declare statistically significant variables on the basis of p < 0.05 in the multivariable logistic regression model.

Results

The prevalence of pneumonia among under-five children in the current study was found to be 12% with 95% CI: 10% to 14.4%. The presence of unpaved road within 100 m of the house (AOR = 2.27, 95% CI: 1.41-3.66), living within 100 m of heavy traffic (AOR = 1.94, 95% CI: 1.19-3.16), the habit of not opening doors while cooking (AOR = 1.62, 95% CI: 1.01-2.62), the presence of cockroach infestation (AOR = 1.98, 95% CI: 1.25-3.14), and new carpet in the house (AOR = 1.75, 95% CI: 1.01-3.03) were statistically significant variables associated with childhood pneumonia.

Conclusions

This study indicated that the prevalence of childhood pneumonia is still high. As such, enhancing strategies that would address unpaved roads within 100 m of the house, living within 100 m of heavy traffic, the habit of not opening doors while cooking, cockroach infestation, and new carpet in the house to reduce the burden of childhood pneumonia needs to be advocated.

Source apportionment of primary and secondary PM2.5: Associations with pediatric respiratory disease emergency department visits in the U.S. State of Georgia

We developed a hybrid chemical transport model and receptor model (CTM-RM) to conduct source apportionment of both primary and secondary PM_2.5 (particulate matter ≤2.5 μm in diameter) at 36 km resolution throughout the U.S. State of Georgia for the years 2005 and 2007. This novel source apportionment model enabled us to estimate and compare associations of short-term changes in 12 PM_2.5 source concentrations (agriculture, biogenic, coal, dust, fuel oil, metals, natural gas, non-road mobile diesel, non-road mobile gasoline, on-road mobile diesel, on-road mobile gasoline, and all other sources) with emergency department (ED) visits for pediatric respiratory diseases. ED visits for asthma (N = 49,651), pneumonia (N = 25,558), and acute upper respiratory infections (acute URI, N = 235,343) among patients aged ≤18 years were obtained from patient claims records. Using a case-crossover study, we estimated odds ratios per interquartile range (IQR) increase for 3-day moving average PM_2.5 source concentrations using conditional logistic regression, matching on day-of-week, month, and year, and adjusting for average temperature, humidity, and holidays. We fit both single-source and multi-source models. We observed positive associations between several PM_2.5 sources and ED visits for asthma, pneumonia, and acute URI. For example, for asthma, per IQR increase in the source contribution in the single-source model, odds ratios were 1.022 (95% CI: 1.013, 1.031) for dust; 1.050 (95% CI: 1.036, 1.063) for metals, and 1.091 (95% CI: 1.064, 1.119) for natural gas. These sources comprised 5.7%, 2.2%, and 6.3% of total PM_2.5 mass, respectively. PM_2.5 from metals and natural gas were positively associated with all three respiratory outcomes. In addition, non-road mobile diesel was positively associated with pneumonia and acute URI.

Effects of Air Pollution on Lung Innate Lymphoid Cells: Review of In Vitro and In Vivo Experimental Studies

Outdoor air pollution is associated with respiratory infections and allergies, yet the role of innate lymphoid cells (ILCs) in pathogen containment and airway hyperresponsiveness relevant to effects of air pollutants on ILCs is poorly understood. We conducted a systematic review to evaluate the available evidence on the effect of outdoor air pollutants on the lung type 1 (ILC1) and type 2 ILCs (ILC2) subsets. We searched five electronic databases (up to Dec 2018) for studies on the effect of carbon monoxide (CO), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), diesel exhaust particles (DEP), ozone (O₃), and particulate matter (PM) on respiratory ILCs. Of 2209 identified citations, 22 full-text papers were assessed for eligibility, and 12 articles describing experimental studies performed in murine strains (9) and on human blood cells (3) were finally selected. Overall, these studies showed that exposure to PM, DEP, and high doses of O₃ resulted in a reduction of interferon gamma (IFN-γ) production and cytotoxicity of ILC1. These pollutants and carbon nanotubes stimulate lung ILC2s, produce high levels of interleukin (IL)-5 and IL-13, and induce airway hyperresponsiveness. These findings highlight potential mechanisms by which human ILCs react to air pollution that increase the susceptibility to infections and allergies.

Air pollution control and the occurrence of acute respiratory illness in school children of Quito, Ecuador

Because of air quality management and control, traffic-related air pollution has declined in Quito, Ecuador. We evaluated the effect of a city-wide 5-year air pollution control program on the occurrence of acute respiratory illness (ARI). We compared two studies conducted at the same location in Quito: in 2000, 2 years before the policy to control vehicle emission was introduced, and in 2007. Each study involved ~ 730 children aged 6-12 years, observed for 15 weeks. We examined associations between carboxyhemoglobin (COHb) serum concentration-an exposure proxy for carbon monoxide (CO)-ambient CO, and ARI in both cohorts. In 2007, we found a 48% reduction in the ARI incidence (RR 0.52; 95% CI 0.45-0.62, p < 0.0001), and 92% decrease in the percentage of children with COHb > 2.5% as compared to the 2000 study. We found no association between COHb concentrations above the safe level of 2.5% and the ARI incidence (p = 0.736). The decline in air pollution due to vehicle emissions control was associated with a lower incidence of respiratory illness in school children.

Exposure to outdoor air pollution and its human health outcomes: A scoping review

Despite considerable air pollution prevention and control measures that have been put into practice in recent years, outdoor air pollution remains one of the most important risk factors for health outcomes. To identify the potential research gaps, we conducted a scoping review focused on health outcomes affected by outdoor air pollution across the broad research area. Of the 5759 potentially relevant studies, 799 were included in the final analysis. The included studies showed an increasing publication trend from 1992 to 2008, and most of the studies were conducted in Asia, Europe, and North America. Among the eight categorized health outcomes, asthma (category: respiratory diseases) and mortality (category: health records) were the most common ones. Adverse health outcomes involving respiratory diseases among children accounted for the largest group. Out of the total included studies, 95.2% reported at least one statistically positive result, and only 0.4% showed ambiguous results. Based on our study, we suggest that the time frame of the included studies, their disease definitions, and the measurement of personal exposure to outdoor air pollution should be taken into consideration in any future research. The main limitation of this study is its potential language bias, since only English publications were included. In conclusion, this scoping review provides researchers and policy decision makers with evidence taken from multiple disciplines to show the increasing prevalence of outdoor air pollution and its adverse effects on health outcomes.

Effects of air pollution on hospital visits for pneumonia in children: a two-year analysis from China

Although the effect of air pollution on respiratory health has been identified, few studies can be available to evaluate the association of air pollution with hospital visits for children's pneumonia in China. To explore whether high concentrations of air pollutants (including PM_2.5, PM₁₀, NO₂, and SO₂) are related to hospital visits for pneumonia in children, we conducted a population-based time-series study in Ningbo, China, from January 1st, 2014 to November 1st, 2015. We used a generalized additive Poisson regression model to calculate risk ratios and 95% confidence intervals for the associations of air pollutants and hospital visits for pneumonia in children and found that these four pollutants were associated with the increased hospital visits for pneumonia in children (1.3% for PM2.5, 1.0% for PM10, 2.9% for NO₂, 5.0% for SO₂ per 10-μg/m³ increase in PM2.5, PM10, NO₂, and SO₂, respectively). Stronger associations were observed in the cold seasons and among children under 5 years.

Infant anemia is associated with reduced TLR-stimulated cytokine responses and increased nasopharyngeal colonization with Moxarella catarrhalis

Anemia is a major public health problem in young children. Reports on the role of anemia on infectious diseases remained controversial. We aim to investigate the effect of anemia on innate immunity, nasopharyngeal bacterial colonization, and subsequent infectious outcome. Blood tests were examined at the age of 12 months. TLR-induced cytokine production was assessed by ELISA. Bacteria from nasopharyngeal specimens were identified with traditional culture. Clinical infectious diseases were followed yearly until 3 years of age. Result showed that of the 423 infants, 72 had hemoglobin level ≤ 11 g/dL, among which 55% had normal iron level. There was significant association between hemoglobin level and TLR1-2, and 4 induced IL-6 (p = 0.04, 0.02) and that of TLR4 stimulated TNF-α response (p = 0.04). Children with anemia had higher nasopharyngeal colonization with Moxarella catarrhalis. Clinical analysis did not show anemia to be associated with infectious morbidity. However, children who developed LRTIs had mean lower ferritin levels. We speculated that iron might be the key factor related to infectious morbidity. Thus, to investigate the role of anemia in infectious diseases, it is important to first consider the prevalence of iron deficit, since the incidence of iron deficiency-induced anemia may vary among different regions.

Individual and climate factors associated with acute respiratory infection in Colombian children

The objective of this study was to examine the association between acute respiratory infection recall (ARI-recall) and individual and environmental factors such as climate, precipitation, and altitude above sea level in Colombian children. A secondary analysis of 11,483 Colombian children, whose mothers were interviewed in the 2010 National Demographic and Health Survey, was carried out. The outcome variable was the mother's or caregiver's ARI-recall. The independent variables were expressed at individual, cluster, and municipal levels. At the individual level, we considered health and individual characteristics of the children; at cluster level, we incorporated the altitude above sea level; and at the municipal level, we included precipitation and annual average climate. The association between ARI-recall and independent variables was assessed using a multilevel logistic regression model. ARI-recall was significantly associated with age (OR = 0.61; 95%CI: 0.48-0.79), belonging to an indigenous group (OR = 1.51; 95%CI: 1.16-1.96), and a medium or very poor wealth index (OR = 2.03; 95%CI: 1.25-3.30 and OR = 1.75; 95%CI: 1.08-2.84, respectively). We found interaction between acute child malnutrition and average annual precipitation. Children with acute malnutrition and from municipalities with high annual precipitation had significantly 3.6-fold increased risk of ARI-recall (OR = 3.6; 95%CI: 1.3-10.1). Individual conditions and precipitation are risk factors for ARI-recall in Colombian children. These results could be useful to understand ARI occurrence in children living in tropical countries with similar characteristics.

Etiology of severe pneumonia in Ecuadorian children

BACKGROUND

In Latin America, community-acquired pneumonia remains a major cause of morbidity and mortality among children. Few studies have examined the etiology of pneumonia in Ecuador.

METHODS

This observational study was part of a randomized, double blind, placebo-controlled clinical trial conducted among children aged 2-59 months with severe pneumonia in Quito, Ecuador. Nasopharyngeal and blood samples were tested for bacterial and viral etiology by polymerase chain reaction. Risk factors for specific respiratory pathogens were also evaluated.

RESULTS

Among 406 children tested, 159 (39.2%) had respiratory syncytial virus (RSV), 71 (17.5%) had human metapneumovirus (hMPV), and 62 (15.3%) had adenovirus. Streptococcus pneumoniae was identified in 37 (9.2%) samples and Mycoplasma pneumoniae in three (0.74%) samples. The yearly circulation pattern of RSV (P = 0.0003) overlapped with S. pneumoniae, (P = 0.03) with most cases occurring in the rainy season. In multivariable analysis, risk factors for RSV included younger age (adjusted odds ratio [aOR] = 1.9, P = 0.01) and being underweight (aOR = 1.8, P = 0.04). Maternal education (aOR = 0.82, P = 0.003), pulse oximetry (aOR = 0.93, P = 0.005), and rales (aOR = 0.25, P = 0.007) were associated with influenza A. Younger age (aOR = 3.5, P = 0.007) and elevated baseline respiratory rate were associated with HPIV-3 infection (aOR = 0.94, P = 0.03).

CONCLUSION

These results indicate the importance of RSV and influenza, and potentially modifiable risk factors including undernutrition and future use of a RSV vaccine, when an effective vaccine becomes available.

TRIAL REGISTRATION

ClinicalTrials.gov NCT 00513929.

Clinical characteristics and outcomes of acute community acquired pneumonia in children at a reference public hospital in Pernambuco State, Brazil (2010-2011)

Abstract Objectives: to describe the clinical characteristics and outcomes of acute community acquired pneumonia in children at a reference public hospital in Pernambuco State, Brazil (2010-2011) Methods: pneumonia case series of 80 children aged 28 days to 14 years old at Hospital da Restauração in Pernambuco, Brazil, from 2010 to 2011. Information was noted from medical files, and two comparison groups were created according to the severity of the disease, considering the presence of pleural effusion. Fisher or Mann-Whitney tests were used for comparative analyses. Results: severe pneumonia with pleural effusion was more frequent in children under five years of age (p=0,025), and was associated with longer period of fever (19 x 15 days) and coughing (17 x 13 days), when compared to non-complicated pneumonia cases. Six children (7,5%, 6/80) died, 50% before the fourth day of hospitalization (p=0,001). All deaths were from the pleural effusion group in children from the countryside (p=0,026). Conclusions: the severity of pneumonia in children attended at this hospital is related to younger children, and those transferred from the health units in the countryside, so, early diagnosis and medical intervention are limited by infrastructure and available resources for the health.

Social, economic and environmental risk factors for acute lower respiratory infections among children under five years of age in Rwanda

Background

In low and middle-income countries, acute lower respiratory illness is responsible for roughly 1 in every 5 child deaths. Rwanda has made major health system improvements including its community health worker systems, and it is one of the few countries in Africa to meet the 2015 Millennium Development Goals, although prevalence of acute lower respiratory infections (4 %) is similar to other countries in sub-Saharan Africa. This study aims to assess social, economic, and environmental factors associated with acute lower respiratory infections among children under five to inform potential further improvements in the health system.

Methods

This is a cross-sectional study using data collected from women interviewed in the 2010 DHS about 8,484 surviving children under five. Based on a literature review, we defined 19 health, social, economic, and environmental potential risk factors, tested bivariate associations with acute lower respiratory infections, and advanced variables significant at the 0.1 confidence level to logistic regression modelling. We used manual backward stepwise regression to arrive at a final model. All analyses were performed in Stata v13 and adjusted for complex sample design.

Results

The following factors were independently associated with acute lower respiratory infections: child’s age, anemia level, and receipt of Vitamin A; household toilet type and residence, and season of interview. In multivariate regression, being in the bottom ten percent of households (OR: 1.27, 95 % CI: 0.85-1.87) or being interviewed during the rainy season (OR: 1.61, 95 % CI: 1.24-2.09) was positively associated with acute lower respiratory infections, while urban residence (OR: 0.58, 95 % CI: 0.38-0.88) and being age 24–59 months versus 0–11 months (OR: 0.53, 95 % CI: 0.40-0.69) was negatively associated with acute lower respiratory infections.

Conclusion

Potential areas for intervention including community campaigns about acute lower respiratory infections symptoms and treatment, and continued poverty reduction through rural electrification and modern stove distribution which may reduce use of dirty cooking fuel, improve living conditions, and reduce barriers to health care.

Stunting is associated with poor outcomes in childhood pneumonia

OBJECTIVE

Stunting affects 26.7% of children worldwide, and little is known about its effects on the outcomes of childhood pneumonia. We evaluated the effect of stunting on the outcomes of pneumonia among children enrolled in two large clinical trials.

METHODS

We analysed data from two WHO and USAID-sponsored inpatient treatment trials, the Severe Pneumonia Evaluation Antimicrobial Research study (n = 958) and the Amoxicillin Penicillin Pneumonia International Study (n = 1702), which enrolled children aged 2-59 months across 16 sites in LMICs. We assessed the effect of stunting (height-for-age Z score < -2) on treatment outcome and time to resolution of hypoxaemic pneumonia.

RESULTS

Among 2542 (96%) children with valid data for height, 28% were stunted and 12.8% failed treatment by 5 days. The failure rate among stunted patients was 16.0% vs. 11.5% among non-stunted patients [unadjusted RR = 1.24 (95% CI 1.08, 1.41); adjusted RR = 1.28 (95% CI 1.10, 1.48)]. An inverse relationship was observed between height and failure rates, even among non-stunted children. Among 845 patients with hypoxaemic pneumonia, stunting was associated with a lower probability of normalisation of respiratory rate [HR = 0.63 (95% CI 0.52, 0.75)] and oxygen saturation [HR = 0.74 (95% CI 0.61, 0.89)].

CONCLUSIONS

Stunting increases the risk of treatment failure and is associated with a longer course of recovery in children with pneumonia. Strategies to decrease stunting may decrease the burden of adverse outcomes in childhood pneumonia in low-resource settings.

Exposure to particular matter increases susceptibility to respiratory Staphylococcus aureus infection in rats via reducing pulmonary natural killer cells

Epidemiological studies have shown a correlation between exposure to fine particular matter (PM2.5) and increased respiratory infection, but the mechanisms have remained poorly defined. By using an experimental system we evaluated the effect of PM2.5 exposure on susceptibility to subsequent pulmonary Staphylococcus aureus (S. aureus) infection and its potential mechanisms. Rats were intratracheally instilled with a single dose of PM2.5 sample or PBS followed by an intratracheal inoculation with bacteria S. aureus at 24h after PM2.5 exposure. The rats were examined at 24h post infection. We found that exposure of rats to PM2.5 significantly increased inflammatory cells and levels of IL-6 and TNF-α in bronchoalveolar lavage fluids (BALF). Prior PM2.5 exposure markedly increased the susceptibility of rats to subsequent S. aureus infection. The mechanistic studies showed that alveolar macrophages (AMs) from PM2.5-experienced lungs had depressed phagocytosis of S. aureus, and prior PM2.5 exposure significantly decreased the natural killer (NK) cells recruited into the airways following subsequent S. aureus infection. Further, adoptive transfer of naive NK cells to the lung of prior PM2.5-exposed rats restored PM2.5-impaired antibacterial host defense. The presence of NK cells markedly enhanced the ability of AMs to phagocytose S. aureus ex vivo. Thus, our study identifies PM2.5-impaired NK cell response in the lung to be a novel critical mechanism for PM2.5-mediated susceptibility to S. aureus bacterial infection, which provides a potential mechanism to explain the epidemiological findings that associate ambient air pollution and increased lung bacterial infections. Our findings also suggest that enhancing pulmonary NK cells may be considered for future therapeutic approaches to clinically antibiotic-resistant S. aureus infection in the lung.

Respiratory risks from household air pollution in low and middle income countries

A third of the world's population uses solid fuel derived from plant material (biomass) or coal for cooking, heating, or lighting. These fuels are smoky, often used in an open fire or simple stove with incomplete combustion, and result in a large amount of household air pollution when smoke is poorly vented. Air pollution is the biggest environmental cause of death worldwide, with household air pollution accounting for about 3·5-4 million deaths every year. Women and children living in severe poverty have the greatest exposures to household air pollution. In this Commission, we review evidence for the association between household air pollution and respiratory infections, respiratory tract cancers, and chronic lung diseases. Respiratory infections (comprising both upper and lower respiratory tract infections with viruses, bacteria, and mycobacteria) have all been associated with exposure to household air pollution. Respiratory tract cancers, including both nasopharyngeal cancer and lung cancer, are strongly associated with pollution from coal burning and further data are needed about other solid fuels. Chronic lung diseases, including chronic obstructive pulmonary disease and bronchiectasis in women, are associated with solid fuel use for cooking, and the damaging effects of exposure to household air pollution in early life on lung development are yet to be fully described. We also review appropriate ways to measure exposure to household air pollution, as well as study design issues and potential effective interventions to prevent these disease burdens. Measurement of household air pollution needs individual, rather than fixed in place, monitoring because exposure varies by age, gender, location, and household role. Women and children are particularly susceptible to the toxic effects of pollution and are exposed to the highest concentrations. Interventions should target these high-risk groups and be of sufficient quality to make the air clean. To make clean energy available to all people is the long-term goal, with an intermediate solution being to make available energy that is clean enough to have a health impact.

Ambient air pollution associated with suppressed serologic responses to Pneumocystis jirovecii in a prospective cohort of HIV-infected patients with Pneumocystis pneumonia

BACKGROUND

Ambient air pollution (AAP) may be associated with increased risk for Pneumocystis pneumonia (PCP). The mechanisms underlying this association remain uncertain.

OBJECTIVES

To determine if real-life exposures to AAP are associated with suppressed IgM antibody responses to P. jirovecii in HIV-infected (HIV+) patients with active PCP, and to determine if AAP, mediated by suppressed serologic responses to Pneumocystis, is associated with adverse clinical outcomes.

METHODS

We conducted a prospective cohort study in HIV+ patients residing in San Francisco and admitted to San Francisco General Hospital with microscopically confirmed PCP. Our AAP predictors were ambient air concentrations of particulate matter of < 10 µm in diameter (PM10) and < 2.5 µm in diameter (PM2.5), nitrogen dioxide (NO2), ozone (O3), and sulfur dioxide (SO2) measured immediately prior to hospital admission and 2 weeks prior to admission. Our primary outcomes were the IgM serologic responses to four recombinant P. jirovecii major surface glycoprotein (Msg) constructs: MsgC1, MsgC3, MsgC8, and MsgC9.

RESULTS

Elevated PM10 and NO2 exposures immediately prior to and two weeks prior to hospital admission were associated with decreased IgM antibody responses to P. jirovecii Msg. For exposures immediately prior to admission, every 10 µg/m(3) increase in PM10 was associated with a 25 to 35% decrease in IgM responses to Msg (statistically significant for all the Msg constructs), and every 10 ppb increase in NO2 was associated with a 19-45% decrease in IgM responses to Msg (statistically significant for MsgC8 and MsgC9). Similar findings were seen with exposures two weeks prior to admission, but for fewer of the Msg constructs.

CONCLUSIONS

Real life exposures to PM10 and NO2 were associated with suppressed IgM responses to P. jirovecii Msg in HIV+ patients admitted with PCP, suggesting a mechanism of immunotoxicity by which AAP increases host susceptibility to pulmonary infection.

Childhood anemia at high altitude: risk factors for poor outcomes in severe pneumonia

BACKGROUND

Pneumonia is the leading cause of mortality in young children globally, and factors that affect tissue delivery of oxygen may affect outcomes of pneumonia. We studied whether altitude and anemia influence disease severity and outcomes in young children with World Health Organization-defined severe pneumonia.

METHODS

We analyzed data from the SPEAR (Severe Pneumonia Evaluation Antimicrobial Research) study, a World Health Organization- and USAID-sponsored multinational randomized controlled trial of antibiotics for severe pneumonia among children aged 2 to 59 months in resource-poor settings. The trial enrolled 958 children in 8 sites at varying elevations, classified as high (≥ 2000 m) or low (<2000 m) altitude. We compared illness severity and assessed the effect of anemia on treatment outcome at high and low altitudes, adjusting for potential confounders and study site.

RESULTS

Children at high altitudes had significantly lower oxygen saturation on presentation, more cyanosis, lower systolic blood pressure, and higher hemoglobin. After adjusting for potential confounders, anemia predicted treatment failure in children living at high altitude (relative risk: 4.07; 95% confidence interval: 2.60-6.38) but not at low altitude (relative risk: 1.12; 95% confidence interval: 0.96-1.30). Children at high altitude took longer to reach normoxemia than did children at lower altitudes (5.25 vs 0.75 days; P < .0001).

CONCLUSIONS

Children at high altitude present with more severe disease, and children with anemia at high altitude are at greater risk of poor outcome when being treated for severe pneumonia. Given the high global prevalence of anemia among young children, prevention and treatment of anemia should be a priority in children living at high altitude and could improve outcomes of pneumonia.

Effects of air pollution on lung function and symptoms of asthma, rhinitis and eczema in primary school children

Health effects of ambient air pollution were studied in three groups of schoolchildren living in areas (suburban, urban and urban-traffic) with different air pollution levels in Eskişehir, Turkey. This study involved 1,880 students aged between 9 and 13 years from 16 public primary schools. This two-season study was conducted from January 2008 through March 2009. Symptoms of asthma, rhinitis and eczema were determined by the International Study of Asthma and Allergies in Childhood questionnaire in 2008. Two lung function tests were performed by each child for summer and winter seasons with simultaneous ambient air measurements of ozone (O3), nitrogen dioxide (NO2) and sulfur dioxide (SO2) by passive sampling. Effects of air pollution on impaired lung function and symptoms in schoolchildren were estimated by multivariate logistic regression analyses. Girls with impaired lung function (only for the summer season evaluation) were more observed in suburban and urban areas when compared to urban-traffic area ([odds ratio (OR) = 1.49; 95 % confidence interval (CI) 1.04-2.14] and [OR = 1.69 (95 % CI 1.06-2.71)] for suburban vs. urban-traffic and urban vs. urban-traffic, respectively). Significant association between ambient ozone concentrations and impaired lung function (for an increase of 10 μg m(-3)) was found only for girls for the summer season evaluation [OR = 1.11 (95 % CI 1.03-1.19)]. No association was found for boys and for the winter season evaluation. No association was found between any of the measured air pollutants and symptoms of current wheeze, current rhinoconjunctivitis and current itchy rash. The results of this study showed that increasing ozone concentrations may cause a sub-acute impairment in lung function of school aged children.