Exposure to environmental tobacco smoke as a risk factor for recurrent acute otitis media in children under the age of five years

Health effects associated with exposure to secondhand smoke: a Burden of Proof study

Despite a gradual decline in smoking rates over time, exposure to secondhand smoke (SHS) continues to cause harm to nonsmokers, who are disproportionately children and women living in low- and middle-income countries. We comprehensively reviewed the literature published by July 2022 concerning the adverse impacts of SHS exposure on nine health outcomes. Following, we quantified each exposure-response association accounting for various sources of uncertainty and evaluated the strength of the evidence supporting our analyses using the Burden of Proof Risk Function methodology. We found all nine health outcomes to be associated with SHS exposure. We conservatively estimated that SHS increases the risk of ischemic heart disease, stroke, type 2 diabetes and lung cancer by at least around 8%, 5%, 1% and 1%, respectively, with the evidence supporting these harmful associations rated as weak (two stars). The evidence supporting the harmful associations between SHS and otitis media, asthma, lower respiratory infections, breast cancer and chronic obstructive pulmonary disease was weaker (one star). Despite the weak underlying evidence for these associations, our results reinforce the harmful effects of SHS on health and the need to prioritize advancing efforts to reduce active and passive smoking through a combination of public health policies and education initiatives.

Does Acute Otitis Media in the First Month of Life Increase the Risk for Recurrent Otitis?

Acute otitis media (AOM) is a common childhood illness. The aim of this study was to assess whether AOM in the first month of life predicts recurrent AOM (rAOM) in early childhood. The medical records of all neonates with AOM and isolation of bacterial pathogen from middle-ear fluid during 2005-2010 were reviewed. Neonates without AOM admitted during the same period for neonatal fever workup were included as controls. Information regarding rAOM and possible risk factors were collected through a phone interview with the parents. A total of 84 neonates with AOM were enrolled; 25 (30%) had rAOM compared with 8/79 (10%) in the control group. Neonatal AOM increases 4-fold the odds of rAOM later in childhood (odds ratio = 4; 95% CI = 1.44-11.42; P = .008), independent of smoke exposure, numbers of siblings, AOM in siblings, breastfeeding, day care attendance, or use of pacifier. Neonatal AOM is a significant risk factor for rAOM during infancy.

Tobacco Smoke Exposure and Eustachian Tube Disorders in US Children and Adolescents

OBJECTIVES

To describe the association between active, environmental tobacco smoke (ETS) exposure and the prevalence of eustachian tube dysfunction (ETD) in the U.S. pediatric population.

STUDY DESIGN

Cross-sectional.

SETTING

U.S. representative demographic and audiometric data from the National Health and Nutrition Examination Survey (NHANES);2005-2010.

SUBJECTS AND METHODS

The study consisted of 2,977 children aged 12-19 years. ETD was defined as middle ear pressure <100mm H20. ETS was defined as non-active smoking in individuals with serum cotinine over the limit of detection (≥0.015 ng/mL) and <10 ng/mL(N = 1559).

RESULTS

The prevalence of ETD was 6.1%. After multivariate adjustment for age, sex, body mass index, education level, ethnicity, or having a cold, sinus problem or earache during the last 24 hours, compared to unexposed children, the odds ratios (95% confidence interval) of ETD for those exposed to ETS ages 12-15 in the first, second and third tertile of cotinine concentrations were, respectively, 1.38 (0.53-3.60), 0.99 (0.53-3.60) and 2.67 (1.12-6.34). Similarly, the odds ratios (95% confidence interval) of ETD for those exposed to ETS ages 16-19 in the first, second and third tertile of cotinine concentrations were, respectively, 1.28 (0.48-3.41), 0.99 (0.40-2.48) and 2.86 (1.19-6.88).

CONCLUSION

These data suggest that children and adolescents exposed to high concentrations of ETS may have an increased prevalence of ETD.

Evaluation of a spatially resolved forest fire smoke model for population-based epidemiologic exposure assessment

Exposure to forest fire smoke (FFS) is associated with multiple adverse health effects, mostly respiratory. Findings for cardiovascular effects have been inconsistent, possibly related to the limitations of conventional methods to assess FFS exposure. In previous work, we developed an empirical model to estimate smoke-related fine particulate matter (PM2.5) for all populated areas in British Columbia (BC), Canada. Here, we evaluate the utility of our model by comparing epidemiologic associations between modeled and measured PM2.5. For each local health area (LHA), we used Poisson regression to estimate the effects of PM2.5 estimates and measurements on counts of medication dispensations and outpatient physician visits. We then used meta-regression to estimate the overall effects. A 10 μg/m(3) increase in modeled PM2.5 was associated with increased sabutamol dispensations (RR=1.04, 95% CI 1.03-1.06), and physician visits for asthma (1.06, 1.04-1.08), COPD (1.02, 1.00-1.03), lower respiratory infections (1.03, 1.00-1.05), and otitis media (1.05, 1.03-1.07), all comparable to measured PM2.5. Effects on cardiovascular outcomes were only significant using model estimates in all LHAs during extreme fire days. This suggests that the exposure model is a promising tool for increasing the power of epidemiologic studies to detect the health effects of FFS via improved spatial coverage and resolution.

Influenza vaccines for preventing acute otitis media in infants and children

BACKGROUND

Acute otitis media (AOM) is one of the most common infectious diseases in children. It has been reported that 64% of infants have an episode of AOM by the age of six months and 86% by one year. Although most cases of AOM are due to bacterial infection, it is commonly triggered by a viral infection. In most children it is self limiting, but it does carry a risk of complications. Since antibiotic treatment increases the risk of antibiotic resistance, influenza vaccines might be an effective way of reducing this risk by preventing the development of AOM.

OBJECTIVES

To assess the effectiveness of influenza vaccine in reducing the occurrence of acute otitis media (AOM) in infants and children.

SEARCH METHODS

We searched CENTRAL (2014, Issue 6), MEDLINE (1946 to July week 1, 2014), EMBASE (2010 to July 2014), CINAHL (1981 to July 2014), LILACS (1982 to July 2014), Web of Science (1955 to July 2014) and reference lists of articles to July 2014.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing influenza vaccine with placebo or no treatment in infants and children aged younger than six years old. We included children of either sex and of any ethnicity, with or without a history of recurrent AOM.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened studies, assessed trial quality and extracted data. We performed statistical analyses using the random-effects and fixed-effect models and expressed the results as risk ratio (RR), risk difference (RD) and number needed to treat to benefit (NNTB) for dichotomous outcomes, with 95% confidence intervals (CI).

MAIN RESULTS

We included 10 trials (six trials in high-income countries and four multicentre trials in high-, middle- and low-income countries) involving 16,707 children aged six months to six years. Eight trials recruited participants from a healthcare setting. Nine trials (and all five trials that contributed to the primary outcome) declared funding from vaccine manufacturers. Four trials reported adequate allocation concealment and nine trials reported adequate blinding of participants and personnel. Attrition was low for all trials included in the analysis.The primary outcome showed a small reduction in at least one episode of AOM over at least six months of follow-up (five trials, 4736 participants: RR 0.80, 95% CI 0.67 to 0.96; RD -0.04, 95% CI -0.07 to -0.02; NNTB 25, 95% CI 15 to 50).The subgroup analyses (i.e. number of courses, settings, seasons or types of vaccine administered) showed no differences.There was a reduction in the use of antibiotics in vaccinated children (two trials, 1223 participants: RR 0.70, 95% CI 0.59 to 0.83; RD -0.15, 95% CI -0.30 to -0.00).There was no significant difference in the utilisation of health care for the one trial that provided sufficient information to be included. The use of influenza vaccine resulted in a significant increase in fever (six trials, 10,199 participants: RR 1.15, 95% CI 1.06 to 1.24; RD 0.02, 95% CI -0.00 to 0.05) and rhinorrhoea (six trials, 10,563 children: RR 1.17, 95% CI 1.07 to 1.29; RD 0.09, 95% CI 0.01 to 0.16) but no difference in pharyngitis. No major adverse events were reported.Compared to the protocol, the review included a subgroup analysis of AOM episodes by season, and changed the types of influenza vaccine from a secondary outcome to a subgroup analysis.

AUTHORS' CONCLUSIONS

Influenza vaccine results in a small reduction in AOM. The observed reduction with the use of antibiotics needs to be considered in the light of current recommended practices aimed at avoiding antibiotic overuse. Safety data from these trials are limited. The benefits may not justify the use of influenza vaccine without taking into account the vaccine efficacy in reducing influenza and safety data. The quality of the evidence was high to moderate. Additional research is needed.

Microarray analysis of gene expression alteration in human middle ear epithelial cells induced by micro particle

OBJECTIVES

The primary aim of this study is to reveal the effect of particulate matter (PM) on the human middle ear epithelial cell (HMEEC).

METHODS

The HMEEC was treated with PM (300 μg/ml) for 24 h. Total RNA was extracted and used for microarray analysis. Molecular pathways among differentially expressed genes were further analyzed by using Pathway Studio 9.0 software. For selected genes, the changes in gene expression were confirmed by real-time PCR.

RESULTS

A total of 611 genes were regulated by PM. Among them, 366 genes were up-regulated, whereas 245 genes were down-regulated. Up-regulated genes were mainly involved in cellular processes, including reactive oxygen species generation, cell proliferation, apoptosis, cell differentiation, inflammatory response and immune response. Down-regulated genes affected several cellular processes, including cell differentiation, cell cycle, proliferation, apoptosis and cell migration. A total of 21 genes were discovered as crucial components in potential signaling networks containing 2-fold up regulated genes. Four genes, VEGFA, IL1B, CSF2 and HMOX1 were revealed as key mediator genes among the up-regulated genes. A total of 25 genes were revealed as key modulators in the signaling pathway associated with 2-fold down regulated genes. Four genes, including IGF1R, TIMP1, IL6 and FN1, were identified as the main modulator genes.

CONCLUSIONS

We identified the differentially expressed genes in PM-treated HMEEC, whose expression profile may provide a useful clue for the understanding of environmental pathophysiology of otitis media. Our work indicates that air pollution, like PM, plays an important role in the pathogenesis of otitis media.

Panel 1: Epidemiology, natural history, and risk factors

BACKGROUND

The First International Symposium on Recent Advances in Otitis Media (OM) with Effusion was held in Columbus, Ohio, in 1975. The symposium has been organized in the United States every 4 years since, followed by a research conference to (a) assess major research accomplishments, (b) identify important research questions and opportunities, (c) develop consensus on definitions and terminology, and (d) establish priorities with short- and long-term research goals. One of the principal areas reviewed quadrennially is Epidemiology, Natural History, and Risk Factors.

OBJECTIVE

To provide a review of recent literature on the epidemiology, natural history, and risk factors for OM.

DATA SOURCES AND REVIEW METHODS

A search of OM articles in English published July 2007 to June 2011 was conducted using PubMed and related databases. Those with findings judged of importance for epidemiology, public health, and/or statistical methods were reviewed.

RESULTS

The literature has continued to expand, increasing understanding of the worldwide burden of OM in childhood, complications from treatment failures, and comorbidities. Novel risk factors, including genetic factors, have been examined for OM susceptibility. Population-based studies in Canada, the United States, and other countries confirmed reductions in OM prevalence. Although most studies concentrated on acute OM (AOM) or OM with effusion (OME), a few examined severe chronic suppurative OM (CSOM), a major public health problem in developing countries and for certain indigenous populations around the world.

CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

Recent publications have reinforced earlier epidemiological findings, while extending our knowledge in human population groups with high burden of OM.

Acute otitis media in neonatal life: a review

Acute otitis media is frequently encountered by general practitioners and pediatricians. In the neonatal period acute otitis media may present as an isolated local infection or as part of septicemia. Diagnosis of the condition by otoscopy is difficult. Considering the wide spectrum of middle ear disorders (acute otitis media, otitis media with effusion, chronic suppurative otitis media) one can appreciate why opinions on the management of the condition are diverse. This is a review of the literature on clinical presentation, etiology, risk factors, treatment and prevention of acute otitis media in neonatal life.

A survey of schoolchildren's exposure to secondhand smoke in Malaysia

BACKGROUND

There is a lack of data describing the exposure of Malaysian schoolchildren to Secondhand Smoke (SHS). The aim of this study is to identify factors influencing schoolchildren's exposures to SHS in Malaysia.

METHOD

This cross-sectional study was carried out to measure salivary cotinine concentrations among 1064 schoolchildren (10-11 years) attending 24 schools in Malaysia following recent partial smoke-free restrictions. Parents completed questionnaires and schoolchildren provided saliva samples for cotinine assay.

RESULTS

The geometric mean (GM) salivary cotinine concentrations for 947 non-smoking schoolchildren stratified by household residents' smoking behaviour were: for children living with non-smoking parents 0.32 ng/ml (95% CI 0.28-0.37) (n = 446); for children living with a smoker father 0.65 ng/ml (95% CI 0.57-0.72) (n = 432); for children living with two smoking parents 1.12 ng/ml (95% CI 0.29-4.40) (n = 3); for children who live with an extended family member who smokes 0.62 ng/ml (95% CI 0.42-0.89) (n = 33) and for children living with two smokers (father and extended family member) 0.71 ng/ml (95% CI 0.40-0.97) (n = 44). Parental-reported SHS exposures showed poor agreement with children's self-reported SHS exposures. Multiple linear regression demonstrated that cotinine levels were positively associated with living with one or more smokers, urban residence, occupation of father (Armed forces), parental-reported exposure to SHS and education of the father (Diploma/Technical certificate).

CONCLUSIONS

This is the first study to characterise exposures to SHS using salivary cotinine concentrations among schoolchildren in Malaysia and also the first study documenting SHS exposure using salivary cotinine as a biomarker in a South-East Asian population of schoolchildren. Compared to other populations of similarly aged schoolchildren, Malaysian children have higher salivary cotinine concentrations. The partial nature of smoke-free restrictions in Malaysia is likely to contribute to these findings. Enforcement of existing legislation to reduce exposure in public place settings and interventions to reduce exposure at home, especially to implement effective home smoking restriction practices are required.

Prenatal and postnatal parental smoking and acute otitis media in early childhood

AIM

To explore the associations between acute otitis media in early childhood and prenatal and postnatal tobacco smoke exposure.

METHODS

Subjects were 32 077 children born between 2000 and 2005 in the Norwegian Mother and Child Study with questionnaire data on tobacco smoke exposure and acute otitis media up to 18 months of age. Multivariate regression models were used to obtain adjusted relative risks for acute otitis media.

RESULTS

Acute otitis media was slightly more common in children exposed to parental smoking. The incidence from 0 to 6 months was 4.7% in unexposed children and 6.0% in children exposed both prenatally and postnatally. After adjusting for postnatal exposure and covariates, the relative risk for acute otitis media 0-6 months when exposed to maternal smoking in pregnancy was 1.34, 95% confidence interval: 1.06-1.69. Maternal smoking in pregnancy was associated with acute otitis media up to 12 months of age. Compared with non-exposed children, there was a slightly increased risk of recurrent acute otitis media for children exposed both prenatally and postnatally with a relative risk of 1.24, 95% confidence interval: 1.01-1.52.

CONCLUSION

Even in a cohort with relatively low exposure levels of parental smoking, maternal smoking in pregnancy was associated with an increased risk of acute otitis media in early childhood.

Pediatricians' practices and attitudes about environmental tobacco smoke and parental smoking

OBJECTIVE

To assess pediatric resident and preceptor environmental tobacco smoke (ETS)-reduction practices and attitudes to inform the development of resident tobacco intervention training.

STUDY DESIGN

Pediatricians in a teaching hospital anonymously completed a 65-item survey.

RESULTS

Residents' and preceptors' (n = 93) ETS actions were generally similar. Pediatricians inconsistently intervened across treatment settings and when treating different ETS-related illnesses (eg, 60% "always" assessed during asthma visits, 13% during otitis visits). Less than 50% "always" explained ETS risks to smoking parents and less than 33% "always" advised about creating smoke-free homes. Most pediatricians reported negative attitudes toward smoking parents; however, attitudes were not related to actions. Most frequently cited barriers to ETS action were lack of time and low confidence in effectiveness.

CONCLUSION

Understanding barriers to ETS intervention could promote transdisciplinary (TD) training and intervention approaches that effectively promote pediatrician advice while offloading the time burden of intensive smoking intervention. ETS intervention training should foster pediatrician confidence and TD relationships with affiliated health professionals who could facilitate intervention, referral, and follow-up necessary to sustain smoking behavior change.

The association between smoking during pregnancy and hospital inpatient costs in childhood

Although the health sequelae of smoking during pregnancy are well documented, relatively little is known about its long-term economic implications. The objective of this study was to analyse individual-level data on maternal smoking behaviour and sociodemographic, perinatal and resource utilisation variables in order to estimate the association between smoking during pregnancy and hospital inpatient service utilisation and costs through the first 5 years of the infant's life. Data from the Oxford Record Linkage Study, a collection of birth registrations, death certificates and statistical abstracts of hospital inpatient and day case admissions formed the basis of the investigation. The study population comprised all infants born to women who both lived and delivered in Oxfordshire or West Berkshire during the period 1 January 1980-31 December 1989 (n = 119,028). The cost of each hospital admission, including the initial birth admission, was estimated by multiplying the length of stay by the per diem cost of the respective specialty (pound 1998-1999 sterling). The effect of maternal smoking behaviour on cumulative 5-year hospital inpatient service utilisation and costs was analysed in a series of multivariate analyses, taking account of confounding clinical and sociodemographic factors. Infants born to women who reported smoking during pregnancy were hospitalised for a significantly greater number of days than infants born to women who had either never smoked or had smoked in the past (P < 0.0001). Over the first 5 years of life, the adjusted mean cost difference was estimated at pound sterling 462 (95%CI: pound sterling 353-pound sterling 571) when infants born to women who smoked at least 20 cigarettes per day were compared to infants of non-smoking mothers, and pound sterling 307 (95%CI: pound sterling 221-pound sterling 394) when infants born to women who smoked 10-19 cigarettes per day were compared to infants of non-smoking mothers (P < 0.0001). The results of this study should add an economic dimension to the importance of providing smoking cessation services for pregnant women.

The laws of acute otitis media

One key to successfully navigating the quagmire of otitis media is to understand otitis media and share that understanding with parents. The Laws of Otitis Media can be useful in this endeavor. Another key to success is to help parents understand that they and their child's physician are partners in the goal of preventing AOM as much as possible, and treating episodes as precisely as possible when they occur. Parents need to know that AOM usually occurs at < 3 years of age and most normal children experience some AOM. The number of AOM episodes depends on a combination of inherited factors that are compounded by immature immunity and anatomy plus the degree of exposure to provoking respiratory pathogens. A firm understanding of the difference between AOM and OME makes it simpler to withhold antibiotics for OME; and understanding that infrequent AOM usually gets well without antibiotics also may reduce some of parents' anxieties. Parents of patients with frequent AOM deserve more guidance about the need for more potent antibiotics and the reduced expectations for cure despite use of appropriate antibiotics. Clinicians need to share with parents the fact that most information about antibiotics and AOM comes from studies sponsored by pharmaceutical companies, with the goal of optimizing the chance that the company's drug would appear to be a good choice. Therefore, only by understanding critical study-design characteristics that ensure fair and proper comparison, will the clinician (or parent using the Internet) be able to decide which drugs are best. Because there are so few well-designed studies, pharmacodynamics has become an alternative method to decide which drugs are best. Practitioners may need to rely on an expert to help interpret the application of pharmacodynamics to local AOM pathogens. While shorter courses of antibiotics are attractive from the compliance and perhaps even the reduction of resistance perspective, failure rates will be higher in young children with tough-to-treat AOM. Further, some of the better tasting or more convenient drugs turn out to be less effective in these same hard-to-treat patients. To further minimize parental anxiety, clinicians should share the fact that it is very rare to see severe complications or lifelong hearing problems due to AOM that is reasonably managed. This is important because the available tools to prevent AOM are limited in number and efficacy. The Laws of AOM can be a basis for busy practitioners to establish a structure for constructively sharing information and responsibility with parents concerning AOM.

Environmental risk factors for respiratory infections

In this study, the authors investigated the possible relationship between environmental-including dietary-factors and respiratory and ear infections in children. A sample of 304 children, aged 4-5 y, in Geneva, Switzerland, was studied. Mothers filled out a questionnaire that the authors provided. The questionnaire included items on food frequency, infections, and background factors (e.g., education, housing conditions, parents' smoking habits). Allergy was a risk factor for all infections, and mother's age was a protective factor. Humid conditions at home was a significant risk factor for cold, sore throat, and otitis (odds ratios = 2.71, 3.03, and 2.77, respectively); mold in the home was a significant risk factor for otitis (odds ratio = 2.80); and attending day-care centers was a significant risk factor for cold and bronchitis (odds ratios = 1.36 and 1.89, respectively). Dietary factors were not related to disease risk nor were environmental tobacco smoke or housing conditions generally related to an increased risk.

Parental smoking and respiratory illnesses in Australian children aged 0-4 years: ABS 1989-90 National Health Survey results

OBJECTIVE

This study investigated the associations between parental smoking and respiratory infections in Australian children aged 0-4 years.

METHODS

Data from the ABS 1989-90 National Health Survey were used. The exposure variables examined were maternal, paternal and combined family smoking. Outcome variables were parent-reported chronic or recent asthma, asthma wheeze, bronchitis, influenza, common cold, cough, otitis media and other respiratory conditions. Logistic regression techniques were used to control for confounding by socio-economic status, child's sex, maternal education, place of residence, ethnicity and family size.

RESULTS

Of the 4,281 children in the sample, 45% lived in households with one or more current smokers and 29% had a mother who smoked. Maternal (but not paternal) smoking was significantly associated with asthma (OR 1.52, 95% CI 1.19-1.94) and asthma wheeze (OR 1.51, 95% CI 1.26-1.80). No other significant associations were observed. Positive and significant dose response relationships were found between the amount of maternal smoking and both asthma variables. Population attributable risks were calculated and almost 13% of asthma and asthma wheeze in 0-4 year old Australian children in 1989-90 was estimated to be due to maternal smoking.

CONCLUSION

Large numbers of Australian children live in households with smokers. This study, like others, has shown an association between maternal smoking and respiratory illnesses in young children. Further strategies are needed to prevent or reduce young children's exposure to environmental tobacco smoke in their homes.

Health effects of passive smoking. 4. Parental smoking, middle ear disease and adenotonsillectomy in children

BACKGROUND

A systematic quantitative review was conducted of evidence relating parental smoking to acute otitis media, recurrent otitis media, middle ear effusion, and adenoidectomy and/or tonsillectomy.

METHODS

Forty five relevant publications were identified after consideration of 692 articles selected by electronic search of the Embase and Medline databases using keywords relevant to passive smoking in children. The search was completed in April 1997 and identified 13 studies of acute otitis media, nine of recurrent otitis media, five of middle ear effusion, nine of glue ear surgery, and four of adenotonsillectomy. A quantitative meta-analysis was possible for all outcomes except acute otitis media, using random effects modelling where appropriate to pool odds ratios from each study.

RESULTS

Evidence for middle ear disease is remarkably consistent, with pooled odds ratios if either parent smoked of 1.48 (95% CI 1.08 to 2.04) for recurrent otitis media, 1.38 (1.23 to 1.55) for middle ear effusion, and 1.21 (0.95 to 1.53) for outpatient or inpatient referral for glue ear. Odds ratios for acute otitis media are in the range 1.0 to 1.6. No single study simultaneously addresses selection bias, information bias and confounding, but where these have been investigated or excluded in the design or analysis, the associations with parental smoking persist virtually unchanged. Large French and British studies are inconsistent with regard to the association of parental smoking and tonsillectomy.

CONCLUSIONS

There is likely to be a causal relationship between parental smoking and both acute and chronic middle ear disease in children.

Is there a relationship between proximity to industry and the occurrence of otitis media with effusion in school entrant children?

In a study of the relationship between the prevalence of persistent otitis media with effusion (OME) in school entrant children in Redcar and Cleveland and the distance of the homes of these children from known industrial emission points, 1156 school entrant children were screened for the presence of persistent OME. The social disadvantage scores and map references were determined from the postcode area of each of the study entrants and map references were also obtained of known industrial emission points in the locality. Analyses were conducted on the association between the presence of OME and distance from emission sources and between the presence of OME and disadvantage score. A significantly greater proportion of study entrants with OME lived within 1000 meters of an industrial emission point than further away. However, there was no trend established between the proportion of study entrants with OME and increasing distance from an emissions source, nor was there any significant relationship established between the social disadvantage score of the areas of residence of the study entrants and the presence of OME. Further research is required to establish the effect of confounding variables on this relationship.

Effects of Air Pollution on the Upper Aerodigestive Tract

The main route of contamination of the human body with airborne pollutants is through the upper air and food passages. Because of the delicate balance of the mucous membranes and special sensory organs of these passages with respect to mucociliary activity, local and recruited immune responses, rapid uptake of chemicals, and carcinogenic potential, the ingestion or inhalation of pollutants in the air can be harmful to these internal body barriers. The particular target organs for air pollution effects on the upper aerodigestive tract include the mucosa, olfactory epithelium, auditory receptor cells, glottic epithelium, and adjacent neural and muscular tissues. Hearing loss caused by noise exposure may be aggravated by the concomitant inhalation of solvents. The strongest evidence for the carcinogenic effect of occupational inhalants in the nasal cavity and paranasal sinuses is seen with exposure to hardwood dust, tobacco smoke, furniture making, and leather tanning. With the exception of tobacco smoke, which produces squamous cell carcinomas, the majority of the occupationally related cancers are adenocarcinomas, usually of the intestinal variety. Tobacco smoke, passive or active, may lead to end-artery obliteration at the level of the otic end organ, causing a progressive sensorineural hearing loss. Further environmental research in the upper aerodigestive tract should aim at developing biologic markers to determine early, premalignant tissue changes; identifying the effects of chronic, low-dose toxic exposure on mucous membranes and neurosensory organs; providing field-tested tools for the standardized screening of large at-risk populations.

New prospects in the prevention of otitis media

Otitis media is the most common bacterial infection in children, accounting for a substantial economic burden to the health care system. Together with concern for long-term developmental sequelae, prevention of otitis media has become a high priority area of research. A wide range of factors has been associated with an increased risk of acute otitis media. Most of these factors, however, predispose to upper respiratory tract infection which, in turn, can be considered the most important risk factor for acute otitis media. Conventionally, antimicrobial prophylaxis, tympanostomy tubes and adenoidectomy have been used for prevention of otitis media. At present, the vaccine approach seems to hold the greatest promise for ultimate prevention of otitis media. In addition to the bacterial vaccines, vaccines against the most common viruses predisposing to acute otitis media may also prove valuable in the prevention of otitis media.