Association of environmental tobacco smoking exposure with an increased risk of hospital admissions for pneumonia in children under 5 years of age in Vietnam

Effects of pre-natal and post-natal exposures to air pollution on onset and recurrence of childhood otitis media

BACKGROUND

Despite mounting evidence linking outdoor air pollution with otitis media (OM), the role of air pollutant(s) exposure during which critical window(s) on childhood OM remains unknown.

OBJECTIVES

We sought to identify the key air pollutant(s) and critical window(s) associated with the onset and recurrent attacks of OM in kindergarten children.

METHODS

A combined cross-sectional and retrospective cohort study involving 8689 preschoolers aged 3-6 years was performed in Changsha, China. From 2013-2020, data on air pollutants were collected from ambient air quality monitoring stations in Changsha, and the exposure concentration to each child at their home address was calculated using the inverse distance weighted (IDW) method. The relationship between air pollution and OM in kindergarten children was studied using multiple logistic regression models.

RESULTS

Childhood lifetime OM was associated with PM2.5, SO2 and NO2, with ORs (95% CI) of 1.43 (1.19-1.71), 1.18 (1.01-1.37) and 1.18 (1.00-1.39) by per IQR increase in utero exposure and with PM2.5, PM2.5-10 and PM10, with ORs = 1.15 (1.00-1.32), 1.25 (1.13-1.40) and 1.49 (1.28-1.74) for entire post-natal exposure, respectively. The 2nd trimester in utero and the post-natal period, especially the 1st year, were key exposure time windows to PM2.5 and PM10 associated with lifetime OM and the onset of OM. Similarly, the 4th gestational month was a critical window for all pollutants except CO exposure in relation to lifetime OM and OM onset, but not recurrent OM attacks. PM2.5 exposure during the nine gestational months and PM10 exposure during the first three years had cumulative effects on OM development. Our subgroup analysis revealed that certain children were more susceptible to the OM risk posed by air pollution.

CONCLUSIONS

Early-life exposure to air pollution, particularly PM2.5 during the middle of gestation and PM10 during the early post-natal period, was associated with childhood OM.

Association of exposure to environmental vanadium and manganese with lung function among young children: A population-based study

Exposure to environmental metals has been associated with health outcomes including respiratory health. Little is known about the impact of exposure to environmental metals on lung function among young children in general population. This study aimed to investigate the associations of exposure to metals with lung function among young children in a population-based cohort. A total of 1488 children aged 5-8 years attended a follow-up visit as part of the Longitudinal Investigation of Global Health in Taiwanese Schoolchildren (LIGHTS) cohort. We measured urinary samples of vanadium (median: 1.21 ng/mL; interquartile range (IQR): 0.73-1.98), manganese (median: 0.23 ng/mL; IQR: 0.13-0.47), arsenic (median: 40.51 ng/mL; IQR: 21.66-70.49), nickel (median: 1.09 ng/mL; IQR: 0.31-3.60), and cadmium (median: 0.26 ng/mL; IQR: 0.11-0.43) and performed lung function tests. Urinary vanadium concentrations were inversely associated with FVC (β coefficient for the highest quartile versus the other quartiles: -33.40, p = 0.001), FEV1 (β: -41.31, p < 0.001), FEV1/FVC ratio (β: -1.00, p = 0.009), PEF (β: -92.12, p = 0.004), and FEF25-75 (β: -82.85, p < 0.001), after adjusting for relevant confounders. Urinary manganese concentrations were inversely associated with FVC (β: -26.60, p = 0.007), FEV1 (β: -31.62, p = 0.001), PEF (β: -84.86, p = 0.009), and FEF25-75 (β: -69.21, p = 0.002). Stratification analyses found inverse associations of urinary vanadium and manganese concentrations with lung function parameters predominantly among children exposed to environmental tobacco smoke. We did not find significant associations of urinary arsenic, nickel, and cadmium concentrations with lung function parameters. In conclusion, this study adds new evidence showing inverse associations of vanadium and manganese exposure with lung function among young children in the general population. Children with environmental tobacco smoke exposure are particularly vulnerable to adverse impact of vanadium and manganese exposure on lung function.

Risk Factors Associated with Diarrheal Episodes in an Agricultural Community in Nam Dinh Province, Vietnam: A Prospective Cohort Study

In Vietnam, data on the risk factors for diarrhea at the community level remain sparse. This study aimed to provide an overview of diarrheal diseases in an agricultural community in Vietnam, targeting all age groups. Specifically, we investigated the incidence of diarrheal disease at the community level and described the potential risk factors associated with diarrheal diseases. In this prospective cohort study, a total of 1508 residents were enrolled during the 54-week study period in northern Vietnam. The observed diarrheal incidence per person-year was 0.51 episodes. For children aged <5 years, the incidence per person-year was 0.81 episodes. Unexpectedly, the frequency of diarrhea was significantly higher among participants who used tap water for drinking than among participants who used rainwater. Participants who used a flush toilet had less frequent diarrhea than those who used a pit latrine. The potential risk factors for diarrhea included the source of water used in daily life, drinking water, and type of toilet. However, the direct reason for the association between potential risk factors and diarrhea was not clear. The infection routes of diarrheal pathogens in the environment remain to be investigated at this study site.

Determinants of community acquired pneumonia among 2 to 59 months of age children in Northeast Ethiopia: a case-control study

BACKGROUND

Pneumonia is the leading cause of mortality and morbidity in under-five children. Regardless of this fact, efforts to identify determinants of pneumonia have been limited in the study area. The aim of this study was to identify determinants of community-acquired pneumonia among 2-59 months of age children in Northeast Ethiopia.

METHODS

Facility-based unmatched case-control study was conducted from February to April, 2019 among 444 (148 cases and 296 controls) 2-59 months of age children in Northeast Ethiopia. Cases were children with pneumonia, while controls were non-pneumonia children. Data were collected using a structured and pre-tested questionnaire by integrated management of neonatal and childhood illness trained nurses. The data were entered into Epi Data and then transferred to SPSS version 23 for analysis. Binary logistic regression analysis was used to test associations between the independent and the dependent variables. Variables with P-value ≤ 0.05 in the multivariable logistic regression model were declared as significant variables.

RESULTS

Children having older age mother (AOR = 0.03, 95% CI; 0.01,0.14), having mothers who are housewife (AOR = 0.19, 95% CI; 0.07,0.54), not having separate kitchen (AOR = 5.37; 95% CI: 1.65,17.43), having a history of diarrhea in the last 2 weeks (AOR = 10.2; 95% CI: 5.13, 20.18), having a history of acute lower respiratory infection in the last 2 weeks (AOR = 8.3, 95% CI: 3.32, 20.55) and having a history of parental asthma in the family (AOR = 4.9, 95% CI: 2.42, 10.18) were found to be determinants of community-acquired pneumonia.

CONCLUSIONS

Children having older age mother, having mothers who are housewife, not having separate kitchen, having a history of diarrhea in the last 2 weeks, having a history of acute lower respiratory infection in the last 2 weeks and having a history of parental asthma in the family were found to be determinants of community-acquired pneumonia. Therefore, all health institutions should promote early treatments and prevention of diarrhea and acute lower respiratory infections of under-five children at the health facility and household level.

Risk Factors for Severe Pneumonia According to WHO 2005 Criteria Definition Among Children <5 Years of Age in Thai Binh, Vietnam: A Case-Control Study

Vietnam is one of the 15 countries where the prevalence of child pneumonia is highest. It is a major cause of admission in pediatric hospitals. However, little is known on the burden of severe pneumonia and their risk factors in children <5 years of age in Vietnam. A case–control study was conducted among children aged 2–59 months presenting with pneumonia at the Pediatric Provincial Hospital of Thai Binh. Cases were children with severe pneumonia while controls included those with non-severe pneumonia as defined by the World Health Organization (WHO) classification of 2005. Eighty-three cases and 83 controls were included. Sex ratio was 2.19. Children with severe pneumonia were significantly less likely to receive antibiotics preadmission compared to children with non-severe pneumonia [odds ratio (OR) = 0.16, 95% confidence interval (CI) = 0.06–0.42]. The main risk factors of severe pneumonia were a lack of immunization (OR = 4.77, 95% CI = 1.80–12.65), an exposure to cigarette smoke (OR = 3.87, 95% CI = 1.62–9.23), and having a mother with a low level of education. Children with severe pneumonia were 25 times more likely to present with associated measles with p < 0.0001 and five times more likely to present with diarrhea than children with non-severe pneumonia (p < 0.0001). Improving immunization coverage, educating parents about the risks of passive smoking and the recognition of respiratory distress signs, and facilitating early antibiotic access for infants with acute pulmonary disease should reduce the burden of such illnesses. To implement a national, multicenter study about pneumonia in children, more precise inclusion criteria should be chosen, including radiological and/or biological assessment.

Modeling Healthcare Costs Attributable to Secondhand Smoke Exposure at Home among South Korean Children

Children exposed to secondhand smoke (SHS) are at increased risk for disease. We sought to estimate the medical costs among Korean children who were exposed to SHS at home. A Markov model was developed, including five diseases (asthma, acute otitis media, acute bronchitis, pneumonia and sudden infant death syndrome) that were significantly associated with SHS in children based on a systematic review. The time horizon of the analysis was 20 years (from birth to adulthood), and the cycle length was 1 week. The direct healthcare costs were discounted annually at 5%. Univariate and probabilistic sensitivity analyses were conducted. The Markov model estimated the healthcare costs for 20 years as 659.61 USD per exposed child, an increase of approximately 30% compared to the cost per unexposed child (507.32 USD). Sensitivity analysis suggested that the younger the age of the exposure, the greater the incremental healthcare costs incurred, implying that infants and young children were especially vulnerable to the SHS exposure. Findings of this study could provide key baseline data for future economic evaluations on SHS control policies in South Korea.

Passive Smoking Exposure and Perceived Health Status in Children Seeking Pediatric Care Services at a Vietnamese Tertiary Hospital

Understanding the predictors of health conditions and exposure to secondhand smoke among children is necessary to determine the severity of the issues and identify effective solutions. Despite the significant prevalence in smoking and child exposure to secondhand smoke, there have been only a few studies focusing on this area in Vietnam, and thus the current study aims to fill in this gap. The questionnaires of 435 children aged between 0 and 6 and their caregivers, who agreed to participate in the research, were collected at the Pediatric Department of Bach Mai hospital, Hanoi, in 2016. Multivariable logistic regression was employed to identify factors associated with perceived health status and exposure to secondhand smoke among children in the last 24 h and the last 7 days from the date of the survey. Our study found that 43% of the respondents had smokers in the family, and 46.4% of children were exposed to passive smoking in the last 7 days. Urban children were most frequently exposed to passive smoking at home and in public, whereas in the rural area, the home and relatives’ houses were the most common places for exposure. Compared to children whose caregivers were farmers, children of non-government workers were more likely to be exposed to passive smoking in the last 7 days. Moreover, children in a family having smoking rules and no smokers were less likely to be exposed to passive smoking in the last 24 h and 7 days than those living in a family allowing smoking and having smokers. In conclusion, our study shows that the government needs to implement better public smoking monitoring and encourage caregivers to implement smoke-free households or smoking rules in their houses.

Associations of household environmental tobacco smoke exposure with respiratory symptoms and utilisation of medical services in healthy young children in Hong Kong

INTRODUCTION

Young children are especially vulnerable to environmental tobacco smoke (ETS) exposure. This study was carried out to determine whether household ETS exposure was associated with respiratory symptoms and medical service utilisation among Hong Kong healthy children in their first eighteen months of age.

METHODS

A secondary analysis was done on the data obtained from our previous cross-sectional territory-wide pneumococcal carriage surveillance study in Hong Kong in 2013–2014. All measures were reported by caregivers. Univariable and multivariable analyses were performed to examine the associations between ETS exposure and outcome measures. Covariates included children’s sex, age, body mass index z score, history of breastfeeding, gestational age at birth, birthweight, maternal age, living region, overcrowding of living area, household income, child care attendance, and presence of siblings. Additional adjustment for season and households’ respiratory symptoms were made to ascertain the association between ETS and children’s respiratory symptoms.

RESULTS

The analysis included 1541 children (mean age: 11.2 ± 6.4 months; males: 50.7%). Current household ETS exposure (AOR=1.30; 95% CI: 1.00– 1.66; p=0.050) and postnatal maternal smoking (AOR=2.21; 95% CI: 1.06–4.64; p=0.035) were independently and significantly associated with all-cause doctor consultation in the past 3 months. Children living with more than one household smoker were more likely to have all-cause doctor consultation compared with the non-exposed children (AOR=1.70; 95% CI: 1.04–2.77, p=0.028). Postnatal maternal smoking was associated with all-cause hospitalisation in the past 3 months (AOR=2.48; 95% CI: 1.05–5.86; p=0.039). Children living in a household, where the daily consumption by household smokers was more than 20 cigarettes, were more likely to have respiratory symptoms compared with non-exposed children (AOR=1.99; 95% CI: 1.12–3.52; p=0.016).

CONCLUSIONS

Household ETS exposure in young children was associated with respiratory symptoms and all-cause outpatient or inpatient medical service utilisation. The associations were potentially dose-dependent.

Burden of disease attributable to second-hand smoke exposure: A systematic review

Our aim was to provide a systematic review of studies on the burden of disease due to second-hand smoke (SHS) exposure, reviewing methods, exposure assessment, diseases causally linked to SHS, health outcomes, and estimates available to date. A literature review of studies on the burden of disease from SHS exposure, available in PubMed and SCOPUS, published 2007-2018 in English language, was carried out following the PRISMA recommendations. Overall, 588 studies were first identified, and 94 were eligible. Seventy-two studies were included in the systematic review. Most of them were based on the comparative risk assessment approach, assessing SHS exposure using mainly surveys on exposure at home/workplaces. Diseases more frequently studied were: lung cancer, ischemic heart disease, stroke, chronic obstructive pulmonary disease, asthma and breast cancer in adults; lower respiratory tract infection, otitis media, asthma, sudden infant death syndrome and low birth weight in children. The SHS exposure assessment and the reported population attributable fractions (PAF) were largely heterogeneous. As an example, the PAF from lung cancer varied between 0.6% and 20.5%. Moreover, PAF were estimated applying relative risks and SHS exposures with no consistent definitions or with different age classes. The research gap on the SHS exposure burden is shrinking. However, estimates are not yet available for a number of countries, particularly the Middle Eastern and African countries, and not all diseases with the strongest evidence of causation, such as sudden infant death syndrome, have been explored. Moreover, in some cases the applied methodology revealed relatively low quality of data.

The health and social implications of household air pollution and respiratory diseases

Approximately three billion individuals are exposed to household air pollution (HAP) from the burning of biomass fuels worldwide. Household air pollution is responsible for 2.9 million annual deaths and causes significant health, economic and social consequences, particularly in low- and middle-income countries. Although there is biological plausibility to draw an association between HAP exposure and respiratory diseases, existing evidence is either lacking or conflicting. We abstracted systematic reviews and meta-analyses for summaries available for common respiratory diseases in any age group and performed a literature search to complement these reviews with newly published studies. Based on the literature summarized in this review, HAP exposure has been associated with acute respiratory infections, tuberculosis, asthma, chronic obstructive pulmonary disease, pneumoconiosis, head and neck cancers, and lung cancer. No study, however, has established a causal link between HAP exposure and respiratory disease. Furthermore, few studies have controlled for tobacco smoke exposure and outdoor air pollution. More studies with consistent diagnostic criteria and exposure monitoring are needed to accurately document the association between household air pollution exposure and respiratory disease. Better environmental exposure monitoring is critical to better separate the contributions of household air pollution from that of other exposures, including ambient air pollution and tobacco smoking. Clinicians should be aware that patients with current or past HAP exposure are at increased risk for respiratory diseases or malignancies and may want to consider earlier screening in this population.

An alarmingly high nasal carriage rate of Streptococcus pneumoniae serotype 19F non-susceptible to multiple beta-lactam antimicrobials among Vietnamese children

Background

Understanding the relationship between serotype epidemiology and antimicrobial susceptibility of Streptococcus pneumoniae is essential for the effective introduction of pneumococcal conjugate vaccines (PCVs) and control of antimicrobial-resistant pneumococci.

Methods

We conducted a community-based study in Nha Trang, central Vietnam, to clarify the serotype distribution and pattern of S. pneumoniae antimicrobial susceptibility in children under 5 years of age and to identify risk factors for carrying antimicrobial-resistant strains. Nasopharyngeal swabs collected from children with acute respiratory infections (ARIs) hospitalized between April 7, 2008, and March 30, 2009, and from healthy children randomly selected in July 2008 were subjected to bacterial culture. Minimum inhibitory concentrations (MICs) against S. pneumoniae were determined, and multiplex-polymerase chain reaction (PCR) serotyping assays were performed. Logistic regression was applied to identify risk factors.

Results

We collected 883 samples from 331 healthy children and 552 ARI cases; S. pneumoniae was isolated from 95 (28.7%) healthy children and 202 (36.6%) ARI cases. Age and daycare attendance were significantly associated with pneumococcal carriage. In total, 18.0, 25.8 and 75.6% of the isolates had high MICs for penicillin (≥4 μg/ml), cefotaxime (≥2 μg/ml) and meropenem (≥0.5 μg/ml), respectively. The presence of pneumococci non-susceptible to multiple beta-lactams was significantly associated with serotype 19F (Odds Ratio: 4.23) and daycare attendance (Odds Ratio: 2.56) but not ARIs, age or prior antimicrobial use. The majority of isolates non-susceptible to multiple beta-lactams (90%) were PCV13 vaccine serotypes.

Conclusions

S. pneumoniae serotype 19F isolates non-susceptible to multiple beta-lactams are widely prevalent among Vietnamese children. Vaccine introduction is expected to significantly increase drug susceptibility.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-3861-2) contains supplementary material, which is available to authorized users.

Viral Acute Respiratory Illnesses in Young Infants Increase the Risk of Respiratory Readmission

BACKGROUND

Respiratory viruses cause acute respiratory illness (ARI) in early childhood, but their effect on subsequent ARI admissions is not fully understood. This study aimed to determine the association between initial ARI admission because of viruses including human rhinovirus (HRV), respiratory syncytial virus (RSV), human adenovirus (HAdV) and human metapneumovirus (hMPV) and the risk of ARI readmission in children.

METHODS

Clinical information and nasopharyngeal swab samples were collected from children <2 years old at their initial ARI admission in Nha Trang, Vietnam, from January 2007 to April 2012. The incidence of ARI readmission during the follow-up period (initial admission to 5 years of age) was compared between children with and without 1 of 13 respiratory viruses (influenza virus A, influenza virus B, RSV, hMPV, parainfluenza virus-1, parainfluenza virus-2, parainfluenza virus-3 and parainfluenza virus-4, HRV, human coronavirus-229E, human coronavirus-OC43, HAdV and human bocavirus) at initial admission.

RESULTS

A total of 1941 children were enrolled in the study. Viruses were detected in 1254 (64.6%) children at enrollment; HRV, RSV, HAdV and hMPV were detected in 499 (25.7%), 439 (22.6%), 156 (8.0%) and 47 (2.4%) children, respectively. During the follow-up period (4572.7 person-years), 277 children were readmitted with ARI. Virus-related ARI initial admission was associated with an increased risk of ARI readmission for children who were initially admitted before 6 months of age (adjusted rate ratio, 1.6; 95% confidence interval: 1.1-2.5). HAdV (4.6; 1.8-11.9), hMPV (20.4; 6.2-66.9) and HRV (1.6; 1.0-2.4) were independently associated with the outcome. These associations were not observed for children whose initial admission occurred after 6 months of age.

CONCLUSIONS

HAdV-, hMPV- and HRV-related initial ARI admissions, when occurring during early infancy, increased the risk of subsequent ARI-related readmission.

Residential risk factors for childhood pneumonia: A cross-sectional study in eight cities of China

BACKGROUND

Children's pneumonia is a heavy health burden. Few studies have been carried out on residential risk factors for pneumonia in children. Potential risks associated with dwelling characteristics are still unknown.

METHODS

A cross-sectional study was conducted among children in 8 cities in China during 2010-2011 and 41,176 valid data on children aged 3-8 years old were used in this analysis. To obtain the lifetime-ever incidence of pneumonia in children and identify associations between pneumonia and residential risk factors, chi-square analysis and logistic regression methods were employed. Adjusted odds ratios were used as measures of effect with a 95% confidence interval. Confounding variables in the regression model include children's gender, birthweight, breastfeeding duration, parental smoking and family history of atopy.

RESULTS

The average lifetime-ever incidence of childhood pneumonia was 32.3%. Urban children (33.6%) had more pneumonia than suburban (29.9%) and rural children (24.9%). More residential risk factors were found in urban-dwellings. Boys, low birthweight (<2500 g), breastfeeding duration <6 months, family allergic history, and exposure to parental smoking were found to be associated with higher pneumonia lifetime-ever incidences. Various indicators of dampness, including visible mold spots, damp stains, water damage, water condensation, damp clothing or bedding and mold odor, were also positively associated with pneumonia. Pneumonia incidence increased as the number of dampness indicators increased. Both natural gas and solid cooking fuels were positively associated with pneumonia compared with electricity. Compared with cement, construction materials including synthetic fiber, laminated wood, real wood, paint, emulsion paint and wall paper were positively associated with pneumonia. Daily living habits such as putting bedding to sunshine frequently and cleaning the child's bedroom every day could be effective preventive strategies. A dose-response relationship between the number of residential risk factors and pneumonia was observed when the risk factors number ranged from 7 to 11. Residences with more risk factors had higher lifetime-ever pneumonia odds ratios.

CONCLUSIONS

Indoor environmental factors including dampness, use of solid fuels or natural gas for cooking and use of new construction materials are risk factors for childhood pneumonia. This study gives evidence for the importance of home environment exposures in the occurrence of childhood pneumonia. Actions against the residential risk factors described in this study may help to prevent pneumonia in children.

E-cigarette vapour enhances pneumococcal adherence to airway epithelial cells

E-cigarette vapour contains free radicals with the potential to induce oxidative stress. Since oxidative stress in airway cells increases platelet-activating factor receptor (PAFR) expression, and PAFR is co-opted by pneumococci to adhere to host cells, we hypothesised that E-cigarette vapour increases pneumococcal adhesion to airway cells.Nasal epithelial PAFR was assessed in non-vaping controls, and in adults before and after 5 min of vaping. We determined the effect of vapour on oxidative stress-induced, PAFR-dependent pneumococcal adhesion to airway epithelial cells in vitro, and on pneumococcal colonisation in the mouse nasopharynx. Elemental analysis of vapour was done by mass spectrometry, and oxidative potential of vapour assessed by antioxidant depletion in vitroThere was no difference in baseline nasal epithelial PAFR expression between vapers (n=11) and controls (n=6). Vaping increased nasal PAFR expression. Nicotine-containing and nicotine-free E-cigarette vapour increased pneumococcal adhesion to airway cells in vitro Vapour-stimulated adhesion in vitro was attenuated by the PAFR blocker CV3988. Nicotine-containing E-cigarette vapour increased mouse nasal PAFR expression, and nasopharyngeal pneumococcal colonisation. Vapour contained redox-active metals, had considerable oxidative activity, and adhesion was attenuated by the antioxidant N-acetyl cysteine.This study suggests that E-cigarette vapour has the potential to increase susceptibility to pneumococcal infection.

Risk factors for acute respiratory infections in children under five years attending the Bamenda Regional Hospital in Cameroon

Background

Acute respiratory infections (ARI) are a leading cause of morbidity and mortality in under-five children worldwide. About 6.6 million children less than 5 years of age die every year in the world; 95% of them in low-income countries and one third of the total deaths is due to ARI. This study aimed at determining the proportion of acute respiratory infections and the associated risk factors in children under 5 years visiting the Bamenda Regional Hospital in Cameroon.

Methods

A cross-sectional analytic study involving 512 children under 5 years was carried out from December 2014 to February 2015. Participants were enrolled by a consecutive convenient sampling method. A structured questionnaire was used to collect clinical, socio-demographic and environmental data. Diagnosis of ARI was based on the revised WHO guidelines for diagnosing and management of childhood pneumonia. The data was analyzed using the statistical software EpiInfo™ version 7.

Results

The proportion of ARIs was 54.7% (280/512), while that of pneumonia was 22.3% (112/512). Risk factors associated with ARI were: HIV infection OR_adj 2.76[1.05–7.25], poor maternal education (None or primary only) OR_adj 2.80 [1.85–4.35], exposure to wood smoke OR_adj 1.85 [1.22–2.78], passive smoking OR_adj 3.58 [1.45–8.84] and contact with someone who has cough OR_adj 3.37 [2.21–5.14].

Age, gender, immunization status, breastfeeding, nutritional status, fathers’ education, parents’ age, school attendance and overcrowding were not significantly associated with ARI.

Conclusion

The proportion of ARI is high and is associated with HIV infection, poor maternal education, exposure to wood smoke, passive cigarette smoking, and contact with persons having a cough. Control programs should focus on diagnosis, treatment and prevention of ARIs.

Acute effects of ambient air pollution on lower respiratory infections in Hanoi children: An eight-year time series study

BACKGROUND

Lower respiratory diseases are the most frequent causes of hospital admission in children worldwide, particularly in developing countries. Daily levels of air pollution are associated with lower respiratory diseases, as documented in many time-series studies. However, investigations in low-and-middle-income countries, such as Vietnam, remain sparse.

OBJECTIVE

This study investigated the short-term association of ambient air pollution with daily counts of hospital admissions due to pneumonia, bronchitis and asthma among children aged 0-17 in Hanoi, Vietnam. We explored the impact of age, gender and season on these associations.

METHODS

Daily ambient air pollution concentrations and hospital admission counts were extracted from electronic databases received from authorities in Hanoi for the years 2007-2014. The associations between outdoor air pollution levels and hospital admissions were estimated for time lags of zero up to seven days using Quasi-Poisson regression models, adjusted for seasonal variations, meteorological variables, holidays, influenza epidemics and day of week.

RESULTS

All ambient air pollutants were positively associated with pneumonia hospitalizations. Significant associations were found for most pollutants except for ozone and sulfur dioxide in children aged 0-17. Increments of an interquartile range (21.9μg/m³) in the 7-day-average level of NO₂ were associated with a 6.1% (95%CI 2.5% to 9.8%) increase in pneumonia hospitalizations. These associations remained stable in two-pollutant models. All pollutants other than CO were positively associated with hospitalizations for bronchitis and asthma. Associations were weaker in infants than in children aged 1-5.

CONCLUSION

Strong associations between hospital admissions for lower respiratory infections and daily levels of air pollution confirm the need to adopt sustainable clean air policies in Vietnam to protect children's health.

Prevalence of Smoking and Associated Factors: Evidence From the CHILILAB Demographic Surveillance System in Vietnam

This study analyzed secondary data from Chi Linh Health and Demographic Surveillance System (CHILILAB) database to identify smoking prevalence and associated demographic factors. Data were extracted from the database of the CHILILAB 2016, which included information on individual smoking behaviors, as well as individual and household demographic data. Descriptive and binary logistic regression analyses were performed with significance level of 0.05. The smoking prevalences were 34.7%, 0.9%, and 16.1% for men, women, and both genders, respectively. A total of 78.2% of current smokers smoked daily inside their houses. Lower smoking status was associated with younger age, being student, rich, and/or single. Future efforts should not only spend on further reduction of smoking rate in Chi Linh Town but should also pay special attention on reducing the prevalence of in-home smoking. This will help to decrease the risk of nonsmokers being exposed to secondhand smoke in their home environment.

The association between environmental tobacco smoke exposure and childhood respiratory disease: a review

INTRODUCTION

Childhood respiratory illness is a major cause of morbidity and mortality particularly in low and middle-income countries. Environmental tobacco smoke (ETS) exposure is a recognised risk factor for both acute and chronic respiratory illness. Areas covered: The aim of this paper was to review the epidemiology of ETS exposure and impact on respiratory health in children. We conducted a search of 3 electronic databases of publications on ETS and childhood respiratory illness from 1990-2015. Key findings were that up to 70% of children are exposed to ETS globally, but under-reporting may mask the true prevalence. Maternal smoking and ETS exposure influence infant lung development and are associated with childhood upper and lower respiratory tract infection, wheezing or asthma. Further, exposure to ETS is associated with more severe respiratory disease. ETS exposure reduces lung function early in life, establishing an increased lifelong risk of poor lung health. Expert commentary: Urgent and effective strategies are needed to decrease ETS exposure in young children to improve child and long-term lung health in adults especially in low and middle income countries where ETS exposure is increasing.

Respiratory viruses detected in Mexican children younger than 5 years old with community-acquired pneumonia: a national multicenter study

Background

Acute respiratory infections are the leading cause of mortality in children worldwide, especially in developing countries. Pneumonia accounts for 16% of all deaths of children under 5 years of age and was the cause of death of 935 000 children in 2015. Despite its frequency and severity, information regarding its etiology is limited. The aim of this study was to identify respiratory viruses associated with community-acquired pneumonia (CAP) in children younger than 5 years old.

Methods

One thousand four hundred and four children younger than 5 years of age with a clinical and/or radiological diagnosis of CAP in 11 hospitals in Mexico were included. Nasal washes were collected, placed in viral medium, and frozen at −70 °C until processing. The first 832 samples were processed using the multiplex Bio‐Plex/Luminex system and the remaining 572 samples using the Anyplex multiplex RT-PCR. Clinical data regarding diagnosis, clinical signs and symptoms, radiographic pattern, and risk factors were obtained and recorded.

Results

Of the samples tested, 81.6% were positive for viruses. Respiratory syncytial virus (types A and B) was found in 23.7%, human enterovirus/rhinovirus in 16.6%, metapneumovirus in 5.7%, parainfluenza virus (types 1–4) in 5.5%, influenza virus (types A and B) in 3.6%, adenovirus in 2.2%, coronavirus (NL63, OC43, 229E, and HKU1) in 2.2%, and bocavirus in 0.4%. Co-infection with two or more viruses was present in 22.1%; 18.4% of the samples were negative. Using biomass for cooking, daycare attendance, absence of breastfeeding, and co-infections were found to be statistically significant risk factors for the presence of severe pneumonia.

Conclusions

Respiratory syncytial virus (types A and B), human enterovirus/rhinovirus, and metapneumovirus were the respiratory viruses identified most frequently in children younger than 5 years old with CAP. Co-infection was present in an important proportion of the children.

Exposure to paternal tobacco smoking increased child hospitalization for lower respiratory infections but not for other diseases in Vietnam

Exposure to environmental tobacco smoke (ETS) is an important modifiable risk factor for child hospitalization, although its contribution is not well documented in countries where ETS due to maternal tobacco smoking is negligible. We conducted a birth cohort study of 1999 neonates between May 2009 and May 2010 in Nha Trang, Vietnam, to evaluate paternal tobacco smoking as a risk factor for infectious and non-infectious diseases. Hospitalizations during a 24-month observation period were identified using hospital records. The effect of paternal exposure during pregnancy and infancy on infectious disease incidence was evaluated using Poisson regression models. In total, 35.6% of 1624 children who attended follow-up visits required at least one hospitalization by 2 years of age, and the most common reason for hospitalization was lower respiratory tract infection (LRTI). Paternal tobacco smoking independently increased the risk of LRTI 1.76-fold (95% CI: 1.24-2.51) after adjusting for possible confounders but was not associated with any other cause of hospitalization. The population attributable fraction indicated that effective interventions to prevent paternal smoking in the presence of children would reduce LRTI-related hospitalizations by 14.8% in this epidemiological setting.

Exposure to tobacco smoke and childhood rhinitis: a population-based study

Exposure to tobacco smoke has been associated with harmful effects on child health. The association between tobacco smoke exposure and childhood rhinitis has not been established in developed or developing countries. We investigated the association between serum cotinine levels and rhinitis in a population sample of 1,315 Asian children. Serum cotinine levels were positively associated with rhinitis ever (adjusted odds ratio [AOR] = 2.95; 95% confidence interval [CI]: 1.15–7.60) and current rhinitis (AOR = 2.71; 95% CI: 1.07–6.89), while the association for physician-diagnosed rhinitis approaching borderline significance (AOR = 2.26; 95% CI: 0.88–5.83). Stratified analyses demonstrated significant association of serum cotinine levels with current rhinitis among children without allergic sensitization (AOR = 6.76; 95% CI: 1.21–37.74), but not among those with allergic sensitization. Serum cotinine levels were positively associated with rhinitis ever (AOR = 3.34; 95% CI: 1.05–10.61) and current rhinitis (AOR = 4.23; 95% CI: 1.28–13.97) among adolescents but not in children aged less than 10 years. This population-based study demonstrates supportive evidence for positive association of tobacco smoke exposure with rhinitis, while the effect is mainly confined to non-allergic rhinitis and more pronounced in adolescents than in young children, highlighting the need for raising public health awareness about the detrimental effects of tobacco smoke exposure on children’s respiratory health.

Exploring pneumonia risk factors in Vietnamese infants: a survey of new mothers

OBJECTIVE

To understand the prevalence of pneumonia risk factors and perceived barriers to risk factor reduction among Vietnamese infants.

METHODS

We conducted a cross-sectional survey of mothers in the postnatal wards of Da Nang Hospital for Women and Children in central Vietnam from 10 February 2017 to 24 February 2017.

RESULTS

Of 286 mothers surveyed, 259 (91%) initiated breast feeding and 207 (72%) intended to continue exclusive breast feeding for 6 months. No mother smoked cigarettes, but 42% of fathers did. Mothers' decision not to smoke was motivated by concerns for their own health and that of their baby. Households rarely used wood or coal for cooking (6%). Mothers indicated near universal (99%) uptake of the National Expanded Program of Immunization vaccinations. Few (64; 22%) mothers knew about the pneumococcal conjugate vaccine; 56/64 (88%) indicated that they would purchase it for their infants. Family members rarely influenced mothers' decisions about breast feeding or vaccination, except in two instances where fathers were concerned about vaccine-related adverse effects.

CONCLUSION

Modifiable pneumonia risk factors were uncommon among newborn babies in central Vietnam, apart from paternal cigarette smoke exposure. Successful local implementation of the WHO Essential Newborn Care package as well as high levels of maternal education and decision autonomy was observed.

Risk factors for child pneumonia - focus on the Western Pacific Region

Pneumonia is a major cause of disease and death in infants and young children (aged <5 years) globally, as it is in the World Health Organization Western Pacific region. A better understanding of the underlying risk factors associated with child pneumonia is important, since pragmatic primary prevention strategies are likely to achieve major reductions in pneumonia-associated morbidity and mortality in children. This review focuses on risk factors with high relevance to the Western Pacific region, including a lack of exclusive breastfeeding, cigarette smoke and air pollution exposure, malnutrition and conditions of poverty, as well as common co-morbidities. Case management and vaccination coverage have been considered elsewhere.

Risk Factors for Presumed Bacterial Pneumonia Among HIV-uninfected Children Hospitalized in Soweto, South Africa

BACKGROUND

Pneumonia is a leading cause of child morbidity and death. Data on risk factors can guide prevention efforts. Within a study on pneumococcal conjugate vaccine effectiveness, we investigated risk factors for presumed bacterial pneumonia (PBP).

METHODS

PBP cases were human immunodeficiency virus (HIV) uninfected children with lower respiratory tract infection and consolidation on chest radiograph or nonconsolidated infiltrate with C-reactive protein ≥40 mg/L hospitalized at Chris Hani Baragwanath Academic Hospital (CHBAH) in Soweto. Age-matched community controls were identified using CHBAH birth records ±1 week of case birth date. Data were analyzed using conditional logistic regression.

RESULTS

A total of 889 PBP cases (median age 9 months) were matched to 2628 controls. Crowding was a significant risk factor among well-nourished children (adjusted odds ratio [aOR]: 2.29, 95% confidence interval [CI]: 1.89-2.78), but not in those with low weight-for-age. Malnutrition was associated with PBP; strength of association was highest in the absence of crowding (aOR: 6.68, 95% CI: 4.74-9.42). Exclusive breastfeeding was protective only among HIV-unexposed children (aOR: 0.65, 95% CI: 0.54-0.78). Self-reported maternal HIV infection was a risk factor among children exclusively breastfeed up to 4 months (aOR: 2.33, 95% CI: 1.53-3.55). Having indoor tap water was protective (aOR: 0.65, 95% CI: 0.54-0.78), whereas a primary care giver who smoked was a risk factor (aOR: 5.15, 95% CI: 2.94-9.03).

CONCLUSIONS

Our findings confirm several known pneumonia risk factors and highlight complex interactions between factors, including HIV exposure, breastfeeding, malnutrition and crowding. Improved housing, reduced secondhand smoke exposure and HIV prevention among women of reproductive age could lessen the child pneumonia burden.

Decreasing In-home Smoking of Adults-Results from a School-based Intervention Program in Viet Nam

It is indicated that children are involuntarily exposed to secondhand smoke from adults, mainly at their home environment. This study aimed at describing the effectiveness of the school-based intervention to decrease the in-home smoking situation of adults so as to decrease children's exposure to secondhand smoke at home during the year 2011–2012 in a rural district in Hanoi, Viet Nam. This school-based intervention program (intervention and control group) involved 804 children aged 8 to 11 years from August 2011 to May 2012 in a rural district of Hanoi, Viet Nam. Children were taught in class about the harmful effects of secondhand smoke and about how to negotiate with fathers not to smoke in-home. Then children applied what they learnt, including staying away from secondhand smoke and persuading fathers not to smoke in-home in order to decrease children's exposure to secondhand smoke. Chi square test, t-test and multinominal logistic regression were applied in data analysis. The results showed that children's reported their father's in-home smoking decreased from 83.0% pre-intervention to 59.8% post-intervention (p < 0.001) in the intervention school while no change happened in the control school. The study found that the better changed smoking location of adult smokers as reported by children associated with the school who received intervention activities (adjusted OR = 2.04; 95% CI: 1.28–3.24). Poorer changed attitudes towards secondhand smoke of children associated with a lower percentage of better change in smoking location of their fathers/other adult smokers (aOR = 0.51, 95% CI: 0.28–0.96). Children's poorer changed knowledge towards secondhand smoke also associated with poorer changed smoking location of adult smokers (aOR = 2.88, 95% CI: 1.07–7.76). It is recommended by this study that similar school based intervention approaches should be applied in primary schools in Viet Nam to increase children's awareness on the adverse health effects of secondhand smoke and to help them to be able to avoid their exposure to secondhand smoke at their home environment.

Risk factors for community-acquired pneumonia in children under five years of age in the post-pneumococcal conjugate vaccine era in Brazil: a case control study

BACKGROUND

Pneumonia plays an important role in children's morbidity and mortality. In Brazil, epidemiological and social changes occurred concomitantly with the universal introduction of the 10-valent pneumococcal conjugate vaccine. This study identified risk factors for pneumonia following the implementation of a pneumococcal vaccination program.

METHODS

A hospital-based, case-control study involving incident cases of pneumonia in children aged 1-59 months was conducted between October 2010 and September 2013 at a tertiary hospital in northeastern Brazil. The diagnosis of pneumonia was based on the World Health Organization (WHO) criteria. The control group consisted of children admitted to the day-hospital ward for elective surgery. Children with comorbidities were excluded. The risk factors for pneumonia that were investigated were among those classified by the WHO as definite, likely and possible. A multivariate analysis was performed including variables that were significant at p ≤ 0.25 in the bivariate analysis.

RESULTS

The study evaluated 407 children in the case group and 407 children in the control group. Household crowding (OR = 2.15; 95 % CI, 1,46-3,18) and not having been vaccinated against the influenza virus (OR = 3.59; 95 % CI, 2,62-4.91) were the only factors found to increase the likelihood of pneumonia. Male gender constituted a protective factor (OR = 0.53; 95 % CI, 0,39-0,72).

CONCLUSION

Changes on risk factors for pneumonia were most likely associated with the expansion of the vaccination program and social improvements; however, these improvements were insufficient to overcome inequalities, given that household crowding remained a significant risk factor. The protection provided by the influenza vaccine must be evaluated new etiological studies. Furthermore, additional risk factors should be investigated.

Impact of Tobacco Smoke and Nicotine Exposure on Lung Development

Tobacco smoke and nicotine exposure during prenatal and postnatal life can impair lung development, alter the immune response to viral infections, and increase the prevalence of wheezing during childhood. The following review examines recent discoveries in the fields of lung development and tobacco and nicotine exposure, emphasizing studies published within the last 5 years. In utero tobacco and nicotine exposure remains common, occurring in approximately 10% of pregnancies within the United States. Exposed neonates are at increased risk for diminished lung function, altered central and peripheral respiratory chemoreception, and increased asthma symptoms throughout childhood. Recently, genomic and epigenetic risk factors, such as alterations in DNA methylation, have been identified that may influence the risk for long-term disease. This review examines the impact of prenatal tobacco and nicotine exposure on lung development with a particular focus on nicotinic acetylcholine receptors. In addition, this review examines the role of prenatal and postnatal tobacco smoke and nicotine exposure and its association with augmenting infection risk, skewing the immune response toward a T-helper type 2 bias and increasing risk for developing an allergic phenotype and asthmalike symptoms during childhood. Finally, this review outlines the respiratory morbidities associated with childhood secondhand smoke and nicotine exposure and examines genetic and epigenetic modifiers that may influence respiratory health in infants and children exposed to in utero or postnatal tobacco smoke.

Public Policy to Protect Children From Tobacco, Nicotine, and Tobacco Smoke

Tobacco use and tobacco smoke exposure are among the most important health threats to children, adolescents, and adults. There is no safe level of tobacco smoke exposure. The developing brains of children and adolescents are particularly vulnerable to the development of tobacco and nicotine dependence. Tobacco is unique among consumer products in that it causes disease and death when used exactly as intended. Tobacco continues to be heavily promoted to children and young adults. Flavored and alternative tobacco products, including little cigars, chewing tobacco, and electronic nicotine delivery systems are gaining popularity among youth. This statement describes important evidence-based public policy actions that, when implemented, will reduce tobacco product use and tobacco smoke exposure among youth and, by doing so, improve the health of children and young adults.

Clinical Practice Policy to Protect Children From Tobacco, Nicotine, and Tobacco Smoke

Tobacco dependence starts in childhood. Tobacco exposure of children is common and causes illness and premature death in children and adults, with adverse effects starting in the womb. There is no safe level of tobacco smoke exposure. Pediatricians should screen for use of tobacco and other nicotine delivery devices and provide anticipatory guidance to prevent smoking initiation and reduce tobacco smoke exposure. Pediatricians need to be aware of the different nicotine delivery systems marketed and available.Parents and caregivers are important sources of children's tobacco smoke exposure. Because tobacco dependence is a severe addiction, to protect children's health, caregiver tobacco dependence treatment should be offered or referral for treatment should be provided (such as referral to the national smoker's quitline at 1-800-QUIT-NOW). If the source of tobacco exposure cannot be eliminated, counseling about reducing exposure to children should be provided.Health care delivery systems should facilitate the effective prevention, identification, and treatment of tobacco dependence in children and adolescents, their parents, and other caregivers. Health care facilities should protect children from tobacco smoke exposure and tobacco promotion. Tobacco dependence prevention and treatment should be part of medical education, with knowledge assessed as part of board certification examinations.

Protecting Children From Tobacco, Nicotine, and Tobacco Smoke

This technical report serves to provide the evidence base for the American Academy of Pediatrics' policy statements "Clinical Practice Policy to Protect Children From Tobacco, Nicotine, and Tobacco Smoke" and "Public Policy to Protect Children From Tobacco, Nicotine, and Tobacco Smoke." Tobacco use and involuntary exposure are major preventable causes of morbidity and premature mortality in adults and children. Tobacco dependence almost always starts in childhood or adolescence. Electronic nicotine delivery systems are rapidly gaining popularity among youth, and their significant harms are being documented. In utero tobacco smoke exposure, in addition to increasing the risk of preterm birth, low birth weight, stillbirth, placental abruption, and sudden infant death, has been found to increase the risk of obesity and neurodevelopmental disorders. Actions by pediatricians can help to reduce children's risk of developing tobacco dependence and reduce children's involuntary tobacco smoke exposure. Public policy actions to protect children from tobacco are essential to reduce the toll that the tobacco epidemic takes on our children.

Population based cohort study for pediatric infectious diseases research in Vietnam

A population-based cohort study on pediatric infectious diseases was established at Khanh Hoa Province, central Vietnam in 2006, to determine the etiology and risk factors for severe pediatric infectious diseases (SPID) such as acute respiratory infection (ARI), diarrhea and dengue which are the major causes of under 5 mortality. A population census survey was conducted in Nha-Trang and Ninh-Hoa to collect demographic, social-behavioral data and disease burden on SPID. The study site covered a population of 353,525 residing in 75,826 households with 24,781 children less than 5 years. Hospital databases from two hospitals covering the region were obtained. Linking the census and hospital databases, we were able to investigate on a variety of SPID such as environmental tobacco smoking exposure and increased risked of pediatric pneumonia hospitalization, population density, water supply and risk of dengue fever and animal livestock and risk of hospitalized diarrhea. To determine incidence, viral etiology and risk factors for pediatric ARI/pneumonia, we setup a population based prospective hospitalized Pediatric ARI surveillance at Khanh Hoa General Hospital, Nha-Trang in February 2007. The study has revealed RSV, rhinovirus and influenza A as major viral pathogens, role of multiple viral infection and its interaction with bacteria in the development of pneumonia. In addition, we are also conducting a birth cohort study to investigate the incidence of congenital infection and its impact on physical-neurological development, and role of host genetic polymorphism on SPID hospitalization in Vietnam. Population mobility, high cost of regular census update and low mortality are the challenges.

Impact of 2009 pandemic influenza among Vietnamese children based on a population-based prospective surveillance from 2007 to 2011

Background

Influenza virus is one of the major viral pathogens causing pediatric acute respiratory infection (ARI). The spread of pandemic influenza A (A(H1N1)pdm09) in 2009 around the globe had a huge impact on global health.

Objective

To investigate the impact of A(H1N1)pdm09 on pediatric ARI in Vietnam.

Study design

An ongoing population-based prospective surveillance in central Vietnam was used. All children aged <15 years residing in Nha Trang city, enrolled to the ARI surveillance in Khanh Hoa General Hospital, from February 2007 through March 2011 were studied. Clinical data and nasopharyngeal swab samples were collected. Influenza A was detected and genotyped by multiplex polymerase chain reaction assays and sequencing.

Results

Among enrolled 2736 hospitalized ARI cases, 354 (13%) were positive for influenza A. Genotyping results revealed that seasonal H3N2 and H1N1 (sea-H1N1) viruses were cocirculating before A(H1N1)pdm09 appeared in July 2009. The A(H1N1)pdm09 replaced the sea-H1N1 after the pandemic. The majority of influenza A cases (90%) were aged <5 years with incidence rate of 537 (387–775) per 100 000 population. Annual incidence rates of hospitalized influenza cases for pre-, initial and post-pandemic periods among children aged <5 year were 474, 452, and 387 per 100 000, respectively. Children with A(H1N1)pdm09 were elder, visited the hospital earlier, less frequently had severe signs, and were less frequently associated with viral coinfection compared with seasonal influenza cases.

Conclusions

The A(H1N1)pdm09 did not increase the influenza annual hospitalization incidence or disease severity compared with seasonal influenza among pediatric ARI cases in central Vietnam.

Risk factors for severe acute lower respiratory infections in children: a systematic review and meta-analysis

AIM

To identify the risk factors in children under five years of age for severe acute lower respiratory infections (ALRI), which are the leading cause of child mortality.

METHODS

We performed a systematic review of published literature available in the public domain. We conducted a quality assessment of all eligible studies according to GRADE criteria and performed a meta-analysis to report the odds ratios for all risk factors identified in these studies.

RESULTS

We identified 36 studies that investigated 19 risk factors for severe ALRI. Of these, 7 risk factors were significantly associated with severe ALRI in a consistent manner across studies, with the following meta-analysis estimates of odds ratios (with 95% confidence intervals): low birth weight 3.18 (1.02-9.90), lack of exclusive breastfeeding 2.34 (1.42-3.88), crowding - more than 7 persons per household 1.96 (1.53-2.52), exposure to indoor air pollution 1.57 (1.06-2.31), incomplete immunization 1.83 (1.32-2.52), undernutrition - weight-for-age less than 2 standard deviations 4.47 (2.10-9.49), and HIV infection 4.15 (2.57-9.74).

CONCLUSION

This study highlights the role of the above seven risk factors in the development of severe pneumonia in under-five children. In addition, it emphasizes the need for further studies investigating other potential risk factors. Since these risk factors are potentially preventable, health policies targeted at reducing their prevalence provide a basis for decreasing the burden of childhood pneumonia.

Incidence of radiologically-confirmed pneumonia and Haemophilus influenzae type b carriage before Haemophilus influenzae type b conjugate vaccine introduction in Central Vietnam

OBJECTIVES

To determine the incidence of radiologically-confirmed pneumonia (RCP) and Haemophilus influenzae type b (Hib) carriage in central Vietnam as a baseline data before Hib conjugate vaccine introduction.

STUDY DESIGN

In the context of ongoing population-based prospective, hospitalized acute respiratory infection surveillance study, a cross-sectional Hib carriage study was conducted among 1000 children < 5 years of age living in NhaTrang, Vietnam in June 2010, 1 month before the nationwide introduction of Hib conjugate vaccine in Vietnam.

RESULTS

The incidence of RCP hospitalizations among children < 5 years of age was 3.3 per 1000 children. The highest incidence was observed among children 12-23 month age group (8.3 per 1000). Haemophilus influenzae carriage was detected in 37% of the children and Hib carriage rate was 3%. Eighty-two percent of the Haemophilus influenzae had TEM β-lactamase resistance gene. The presence of 6 or more family members was associated with an increased rate of Hib carriage (P = .04).

CONCLUSIONS

Incidence of RCP and Hib carriage in this cross-sectional survey are lower compared with other studies. Continued surveillance for invasive Hib disease and sequential Hib carriage surveys are needed to support future assessments of the impact of Hib conjugate vaccine in Vietnam.

Determining the burden of secondhand smoke exposure on the respiratory health of Thai children

BACKGROUND

The impact of secondhand smoke (SHS) on Southeast Asian children's health has been assessed by a limited number of studies. The purpose of this study was to determine whether in Thailand, pre- and postnatal exposure to SHS is associated with acute lower respiratory conditions in young children.

METHODS

We conducted a case control study of 462 children under age five admitted with acute lower respiratory illnesses, including asthma and pneumonia, at a major hospital in Bangkok. We selected 462 comparison controls from the well-child clinic at the hospital and matched them by sex and age. We used a structured questionnaire to collect information about exposure to SHS and other factors. We conducted bivariate and multivariate analyses to identify risk factors for acute lower respiratory conditions.

RESULTS

The number of cigarettes smoked at home per day by household members was significantly greater among cases. A greater number of household caregivers of cases held and carried children while smoking as compared to controls (26% versus 7%, p <0.05). Cases were more likely to have been exposed to SHS in the household (adjusted OR = 3.82, 95% CI = 2.47-5.9), and outside (adjusted OR = 2.99, 95% CI = 1.45-6.15). Parental lower educational level and low household income were also associated with respiratory illnesses in Thai children under five.

CONCLUSIONS

Thai children who are exposed to SHS are at nearly 4 times greater risk of developing acute lower respiratory conditions. Continued effort is needed in Thailand to eliminate children's exposure to SHS, especially at home.

Tobacco control in Vietnam

OBJECTIVES

To investigate the use of tobacco in Vietnam.

STUDY DESIGN

Review study.

METHODS

Data were collected through a review of tobacco-related literature in Vietnam. Grey literature and web content from agencies such as the World Health Organization and the US Centers for Disease Control and Prevention were consulted.

RESULTS

Tobacco smoking is still common in Vietnam, although numerous policies have been issued and implemented over the last two decades. Based on the most recent data (2010), the prevalence of smoking among adults aged >15 years was 23.8%, with a higher percentage among males (47.4%) than females (1.4%). The prevalence of smoking among students aged 13-15 was 3.8% (2007), with a similar gender pattern. The prevalence of exposure to secondhand smoke is of concern, with 73.1% and 55.9% of adults reporting exposure to secondhand smoke at home and at work or other places, respectively. Of the adult respondents, 55.5% believed that smoking may cause lung cancer, stroke and heart disease. Most students (93.4%) and adults (91.6%) had seen anti-smoking media messages. Of the students, 56.4% had seen pro-cigarette advertisements on billboards, 36.9% had seen pro-cigarette advertisements in newspapers or magazines, and 8.2% had been offered free cigarettes by tobacco company representatives. The price of cigarettes decreased by approximately 5% between 1995 and 2006, whereas gross domestic product per capita increased by more than 150%. On average, smokers smoked 13.5 cigarettes per day, and spent US$86 on cigarettes per year. Despite such high levels of tobacco exposure in Vietnam, the total tax on cigarettes remains at 45% of the retail price. Furthermore, only 29.7% of smokers had been advised to quit by a healthcare provider in the past 12 months.

CONCLUSION

Strong enforcement and evidence-based regulations which rounded on MPOWER are needed to help protect current smokers and non-smokers from the devastating effects of tobacco.

Animal livestock and the risk of hospitalized diarrhoea in children under 5 years in Vietnam

OBJECTIVE

To investigate the association between environmental exposure to livestock and incidence of diarrhoea among Vietnamese children.

METHODS

A population-based cohort of 353,525 individuals, living in 75,828 households in Khanh Hoa Province, Vietnam, with baseline data covering geo-referenced information on demography, socio-economic status and household animals was investigated. Geographic information system was applied to calculate the density of livestock. The data were linked to hospitalized diarrhoea cases of children under 5 years recorded at two hospitals treating patients from the area as inpatients in the study area.

RESULTS

Overall, 3116 children with diarrhoea were hospitalized during the study period. The incidence of diarrhoea hospitalization was 60.8/1000 child-years. Male gender, age <2 years, higher number of household members and lack of tap water were significantly associated with an increased risk of diarrhoea. There was no evidence that ownership of livestock increased the risk of diarrhoea. In spatial analysis, we found no evidence that a high density of any animals was associated with an increased risk of diarrhoea.

CONCLUSIONS

Exposure to animals near or in households does not seem to constitute a major risk for diarrhoea in children under the age of 5 in Vietnam. Public health interventions to reduce childhood diarrhoea burden should focus on well-recognized causes such as sanitation, personal hygiene, access to adequate clean water supply and vaccination.

User fee exemption does not affect lower rates of hospital admission of girls in Vietnam

In many countries, girls have been reported to be less often admitted to hospital than boys. We studied the influence of socio-economic factors, education and access to health care on girls' and boys' admission rates for pneumonia, diarrhoea and dengue fever in south-central Vietnam. We explored whether the user fee exemption for children under 6 years introduced in 2005 had an impact on girls' admission rates. In a cohort analysis, we used data from a large census in Khanh Hoa Province conducted in 2006, linked to hospital admission records at individual level. We further analysed a cross-sectional health care utilization survey in a sample of children reported ill at the census. There were 38 731 children under 6 years among a total census population of 353 891. Overall, girls under the age of 6 years were 29% less likely to be admitted to hospital than boys. The gender differences in admission rates in children under 6 years were similar for diarrhoea, pneumonia and dengue. None of the socio-economic and educational factors appeared to affect the gender difference. The user fee exemption starting from October 2005 had no impact on the girls/boys rate ratio of admission. In conclusion, the higher hospital admission rates of boys compared with girls in Vietnam are independent of socio-economic factors and user fees. Higher susceptibility of boys to severe disease could explain part of the gender gap, but profound cultural norms and beliefs may also have contributed to the findings.

Population density, water supply, and the risk of dengue fever in Vietnam: cohort study and spatial analysis

BACKGROUND

Aedes aegypti, the major vector of dengue viruses, often breeds in water storage containers used by households without tap water supply, and occurs in high numbers even in dense urban areas. We analysed the interaction between human population density and lack of tap water as a cause of dengue fever outbreaks with the aim of identifying geographic areas at highest risk.

METHODS AND FINDINGS

We conducted an individual-level cohort study in a population of 75,000 geo-referenced households in Vietnam over the course of two epidemics, on the basis of dengue hospital admissions (n = 3,013). We applied space-time scan statistics and mathematical models to confirm the findings. We identified a surprisingly narrow range of critical human population densities between around 3,000 to 7,000 people/km² prone to dengue outbreaks. In the study area, this population density was typical of villages and some peri-urban areas. Scan statistics showed that areas with a high population density or adequate water supply did not experience severe outbreaks. The risk of dengue was higher in rural than in urban areas, largely explained by lack of piped water supply, and in human population densities more often falling within the critical range. Mathematical modeling suggests that simple assumptions regarding area-level vector/host ratios may explain the occurrence of outbreaks.

CONCLUSIONS

Rural areas may contribute at least as much to the dissemination of dengue fever as cities. Improving water supply and vector control in areas with a human population density critical for dengue transmission could increase the efficiency of control efforts. Please see later in the article for the Editors' Summary.

Air pollution and children's respiratory health - gaps in the global evidence

There is now convincing evidence that air pollution, especially the particulate matter (PM) fraction, adversely affects children's health. In general, the health effects of traffic-derived PM are well described in children living in high-income countries. Conversely, studies into the health effects of PM from biomass and solid fuels are limited to children in lower-income countries. As PM from different combustion sources have components in common (e.g. elemental black carbon) - are we able to extrapolate from the research performed in different countries under different exposure conditions? Using lung function growth and vulnerability to infection as examples of health effects of global significance to children, this review addresses the question whether high-income-country research into air pollution can inform effects of pollution in low-income countries and vice versa.

Effect of passive smoking on blood lymphocyte apoptosis in children

BACKGROUND

Passive smoking is a well-known risk factor for both recurrent respiratory infections and disturbed lipid profile. Whether passive smoking problems are related to altered lymphocyte survival and its relation to altered lipid profile are the points of concern in this work.

MATERIALS AND METHODS

Urinary cotinine and creatinine levels as well as lipid profile and flow cytometric assessment of apoptosis of peripheral blood lymphocytes (PBL) were assessed in 26 children with history of indoor exposure to cigarette smokers in comparison with 14 matched children with no such history.

RESULTS

Lipid profile showed significantly higher mean levels of triglycerides, cholesterol and low-density lipoprotein (LDL) and significantly lower mean levels of high-density lipoprotein (HDL) in passive smoking children compared to nonpassive-smoking ones. Furthermore, cotinine parameters were positively correlated with triglycerides and LDL and negatively correlated with HDL. Early apoptosis of PBL was significantly higher in exposed vs nonexposed ones.

CONCLUSIONS

Passive smoking in children could be a risk factor for enhanced lymphocytic apoptosis. It is possible that altered lipid profile may play a role in the increased risk. The impact of this lymphocytic derangement on increased frequency of infections is noticeable.

Adhesion of Streptococcus pneumoniae to human airway epithelial cells exposed to urban particulate matter

BACKGROUND

Epidemiologic studies report an association between pneumonia and urban particulate matter (PM) less than 10 microns (μm) in aerodynamic diameter (PM(10)). Streptococcus pneumoniae is a common cause of bacterial pneumonia worldwide. To date, the mechanism whereby urban PM enhances vulnerability to S pneumoniae infection is unclear. Adhesion of S pneumoniae to host cells is a prerequisite for infection. Host-expressed proteins, including the receptor for platelet-activating factor (PAFR), are co-opted by S pneumoniae to adhere to lower airway epithelial cells.

OBJECTIVES

To define whether inhalable urban PM enhances the adhesion of S pneumoniae to airway epithelial cells.

METHODS

A549 cells were cultured with PM(10) from Leicester (United Kingdom [UK]) and PM(10) and PM less than 2.5 μm in aerodynamic diameter (PM(2.5)) from Accra (Ghana), then infected with S pneumoniae strain D39. Pneumococcal adhesion to human primary bronchial epithelial cells was also assessed. Bacterial adhesion was determined by quantitative culture and confocal microscopy. The role of oxidative stress was assessed by N-acetyl cysteine, and the role of PAFR was assessed by mRNA transcript level, receptor expression, and receptor blocking.

RESULTS

PM(10) (UK) increased S pneumoniae adhesion to both A549 airway epithelial cells and human primary bronchial epithelial cells. PM(10) (Ghana) and PM(2.5) (Ghana) also increased adhesion. Culture of A549 cells by PM(10) (UK) increased PAFR mRNA transcript level and PAFR expression. PM(10) (UK)-stimulated adhesion to A549 cells was attenuated by a PAFR blocker and N-acetyl cysteine.

CONCLUSION

Urban PM increases adhesion of S pneumoniae to human airway epithelial cells. PM-stimulated adhesion is mediated by oxidative stress and PAFR.

Parental and household smoking and the increased risk of bronchitis, bronchiolitis and other lower respiratory infections in infancy: systematic review and meta-analysis

BACKGROUND

Passive smoke exposure increases the risk of lower respiratory infection (LRI) in infants, but the extensive literature on this association has not been systematically reviewed for nearly ten years. The aim of this paper is to provide an updated systematic review and meta-analysis of studies of the association between passive smoking and LRI, and with diagnostic subcategories including bronchiolitis, in infants aged two years and under.

METHODS

We searched MEDLINE and EMBASE (to November 2010), reference lists from publications and abstracts from major conference proceedings to identify all relevant publications. Random effect pooled odds ratios (OR) with 95% confidence intervals (CI) were estimated.

RESULTS

We identified 60 studies suitable for inclusion in the meta-analysis. Smoking by either parent or other household members significantly increased the risk of LRI; odds ratios (OR) were 1.22 (95% CI 1.10 to 1.35) for paternal smoking, 1.62 (95% CI 1.38 to 1.89) if both parents smoked, and 1.54 (95% CI 1.40 to 1.69) for any household member smoking. Pre-natal maternal smoking (OR 1.24, 95% CI 1.11 to 1.38) had a weaker effect than post-natal smoking (OR 1.58, 95% CI 1.45 to 1.73). The strongest effect was on bronchiolitis, where the risk of any household smoking was increased by an OR of 2.51 (95% CI 1.96 to 3.21).

CONCLUSIONS

Passive smoking in the family home is a major influence on the risk of LRI in infants, and especially on bronchiolitis. Risk is particularly strong in relation to post-natal maternal smoking. Strategies to prevent passive smoke exposure in young children are an urgent public and child health priority.

Association between nasopharyngeal load of Streptococcus pneumoniae, viral coinfection, and radiologically confirmed pneumonia in Vietnamese children

BACKGROUND

The interplay between nasopharyngeal bacterial carriage, viral coinfection, and lower respiratory tract infections (LRTIs) is poorly understood. We explored this association in Vietnamese children aged less than 5 years.

METHODS

A hospital-based case-control study of pediatric LRTIs was conducted in Nha Trang, Vietnam. A total of 550 hospitalized children (274 radiologically confirmed pneumonia [RCP] and 276 other LRTIs) were enrolled and 350 healthy controls were randomly selected from the community. Polymerase chain reaction-based methods were used to measure bacterial loads of Streptococcus pneumoniae (SP), Haemophilus influenzae, and Moraxella catarrhalis and to detect 13 respiratory viruses and bacterial serotypes in nasopharyngeal samples of study participants.

RESULTS

The median nasopharyngeal bacterial load of SP was substantially higher in children with RCP compared with healthy controls or children with other LRTIs (P < 0.001). SP load was 15-fold higher in pneumonia children with viral coinfection compared with those children without viral coinfection (1.4 x 10⁷/mL vs. 9.1 x 10⁵/mL; P 0.0001). SP load was over 200-fold higher in serotypeable SP compared with nontypeable SP (2.5 x 10⁶/mL vs. 1 x 10⁴/mL; P < 0.0001). These associations were independent of potential confounders in multiple regression models. No clear association was found between nasopharyngeal load of Haemophilus influenzae or Moraxella catarrhalis and viral coinfection in either RCP or other LRTIs groups.

CONCLUSIONS

An increased load of SP in the nasopharynx was associated with RCP, viral coinfection, and presence of pneumococcal capsule.