Air Pollution and Health: Correlation or Causality? The Case of the Relationship between Exposure to Particles and Cardiopulmonary Mortality

  • Aim was to make a critical assessment of the arguments used in 15 reviews of published studies.

  • Concluded that the observed relationship between particles in air and cardiopulmonary mortality is valid and that most of the causality criteria are respected.

  • There is almost general agreement that risks observed between mortality and exposure to particles are low.


American Indian and Alaska Natives: Health Disparities Overview

  • Respiratory syncytial virus (RSV) infection is a major cause of hospitalization in Alaska Native infants.

    • Caused 1/3 of all hospitalizations in children younger than 3 years of age between 1993-1996.

    • Children with RSV are at risk for other respiratory illnesses.

      • 19% were readmitted with another RSV infection.

      • 34% were rehospitalized with another acute respiratory infection within one year of the first RSV hospitalization.

  • Adult smoking prevalence was highest among American Indians and Alaska Natives—34.1%


Asthma and Bronchiolitis Hospitalizations Among American Indian Children

  • Hospitalization rates for AI/AN infants to be nearly double for those for the general population (61.8 vs 34.2 per 1000 population).

  • Higher rates could be due to the presence of additional risk factors for lower respiratory tract disease.

    • possible environmental (tobacco or other indoor smoke exposure)

    • sociodemographic (poverty and its effect on growth, nutrition, etc)

    • intrauterine (maternal smoking  during pregnancy) effect

    • Concluded that asthma hospitalizations rates for AI/AN children in Washington are similar to those for all children in the state except infants.


Asthma and PM10

  • A recent review describes an average 2% increase in hospitalization and related health care visits and an approximate 3% increase in asthma symptoms for each 10 mg/m3 rise in PM10 as the average across a number of studies.

  • Good epidemiological evidence that asthma symptoms can be worsened by increases in PM10 but less evidence at present that PM10 increases the likelihood of initial sensitisation and introduction of disease.


Asthma Prevalence and Control Characteristics by Race/ Ethnicity—United States, 2002

  • CDC analyzed 2002 data from the Behavioral Risk Factor Surveillance System (BRFSS)

  • Current asthma was highest among non-Hispanic respondents of multiple races (15.6%), followed by non-Hispanic American Indian/Alaska Natives (11.6%)

  • Non-Hispanic black, American Indian/Alaska Native, multiracial, and Hispanic respondents all had less positive asthma profiles, with high percentages reporting three to five of the six negative indicators.

  • Other racial/ethnic populations experience higher asthma mortality and hospitalization rates than non-Hispanic whites while also reporting lower asthma prevalence and fewer outpatient and ED visits.

    • racial/ethnic populations with the highest current asthma prevalence in 2001 (non-Hispanic of multiple races, non-Hispanic American Indian/Alaska Native, and non-Hispanic black) reported higher adult current asthma prevalence in 2002.

    • Possible reasons for variability:

      • demographic

      • socioeconomic (income and education level)

      • environmental factors (outdoor air pollution and climate)

      • physician diagnostic procedures

      • data collection practices

Blacks likely breathe most unhealthy air: Little-known EPA project maps air pollution risk around U.S.

  • “Poor communities, frequently communities of color but not exclusively, suffer disproportionately.”

  • Environmental experts say most pollution inequalities result from historical land use decisions and local development policies.  Also, regulators too often focus on one plant or one pollutant without regard to the cumulative impact they say.

  • Little-known EPA study that assigns risk scores for industrial air pollution in every square kilometer of the United States.

    • mapped by government scientist using the 2000 census.

    • Risk-Screening Environmental Indicators (RSEI) by EPA.


Bronchiolitis-associated hospitalizations among American Indian and Alaska Native children

  • Overall bronchiolitis-associated hospitalizations rate among AI/AN infants <1 year old was considerably higher (61.8 per 1000) than the 1995 estimated bronchiolitis hospitalization rate among all US infants (34.2 per 1000).

  • The highest infant hospitalization rate was noted in the Navajo area (96.3 per 1000)

    • <1 year old

    • 35 % of all bronchiolitis-associated hospitalizations during 1995 were reported in the Navajo area, which accounts for 22% ofthe IHS user population.

  • 60% of all bronchiolitis-associated hospitalizations occurred in the Southwest region.

  • 1994—respiratory system disease accounted for the largest proportion (46.2%) of IHS hospitalizations among children ages 1 to 4 years.

  • One study of AN children living in the Yukon Kuskokwim Delta region of southwestern Alaska documented the highest annual RSV-associated hospitalization rate ever reported among US infants (100 per 1000)

  • 1995—IHS hospitalization rates associated with pneumonia (61.1 per 1000) and asthma (19.7 per 1000) were also considerably higher among infants than national estimates (27.8 per 1000 and 10.0 per 1000, respectively).

  • 95% of the bronchiolitis-associated hospitalizations occurred among AI/AN children < 2 years of age, and the majority (79.7%) occurred among children < 1 year of age.

  • Rates of bronchiolitis-associated hospitalization among AI/AN children receiving care funded by the IHS were nearly twice those among all US children.

    • a peak in hospitalizations during the winter months when RSV outbreaks occur

    • a higher rate among boys than among girls

    • fewer bronchiolitis-associated hospitalizations in the winters of 1991 and 1993

    • few children with concurrently coded conditions placing them at increased risk for serious RSV disease

The Clean Air Act at 35: Preventing death and disease from particulate pollution

  • Prevention of death and disease through clean air strategies

    • Reducing particulate pollution from the long-lived diesel engines in use today.

    • Strengthening clean air standards for new marine engines and locomotives.

    • Lowering the particulate-forming pollution from industrial boilers.

    • More aggressively transitioning the nation’s fleet of coal plants to modern pollution controls.

  • Major health effects of breathing particulate pollution include

    • reduced lung function, coughing, wheezing, cardiac arrhythmias, strokes, lung cancer, and premature death

    • missed school days due to respiratory symptoms, increased use of asthma medications, emergency room visits, hospital admissions


Grass seed field smoke and its impact on respiratory health

  • Suggest that county and the region face a number of health-related problems that appear to be associated with the high levels of fine particles (PM2.5) produced by grass field burning.

    • high county rates of adult asthma and hospitalizations of asthmatics, as well as the drug purchase patterns, suggest an association between the PM2.5 level produced by grass field burning and morbidity.

    • fine particulates produced by combustion and the chemical irritants in the smoke have combined to negatively affect the health of individuals suffering from chemically induced asthma: reactive airway disease (RAD).

  • A 1996 study found that 10% of the residents in eastern Washington and northern Idaho reported needing to purchase more medical care and supplies during field burning and 8% were forced to leave the area entirely.


Prevalence of Asthma and Chronic Respiratory Symptoms Among Alaska Native Children

  • Asthma is the most common chronic disease of childhood, affecting at least 5 million children in the United States and causing significant morbidity among children of all ages.

  • Several factors are highly prevalent in the region may predispose Yup’ik children to acquire asthma, including

    • crowded housing conditions

    • low income levels

    • frequent exposure to environmental tobacco

    • frequent exposure to wood-burning stove emissions

    • extremely high rates of acute lower respiratory tract infections, which may contribute to the development of chronic airway disease, particularly in AN/AI children

    • high rates of postinfectious bronchiectasis

  • characteristics of the YK delta that protect the children from acquiring asthma

    • exposure to concentrated industrial or motor vehicle emissions is rare

    • exposure to allergens is thought to be uncommon

    • have access to an integrated health-care system


Wood-burning stoves and lower respiratory illnesses in Navajo children [Original Studies]

  • Cooking with wood-burning stoves was associated with higher indoor air concentrations of respirable particles and with an increased risk of acute lower respiratory illness (ALRI) in Navajo Children.

    • risk of hospitalization with an ALRI was 5-fold for Navajo children living in houses that cooked with wood, instead of gas or electricity alone.

    • children living in houses with concentrations of respirable suspended particles ³ 65 mg/m3 experienced a 7-fold excess risk of ALRI.

  • case households, as compared to control households:

    • less likely to have electricity

    • more than two rooms

    • mother as the primary caretaker

    • tended to live farther from the clinic

    • slightly more problems with transportation

    • less likely to have cigarette smokers or to smoke traditional herbs in the home most common heating source was wood