Relationship between asthma and the environment

Environmental Issues in Managing Asthma

relationship between asthma and the environment

The role of environmental factors in relation to asthma and allergy has become increasingly topical through the s. There has been wide- spread public. National Environmental Public Health Tracking . an association between increased hospital admissions for asthma and. Med J Malaysia. Sep;50(3) The relationship between prevalence of asthma and environmental factors in rural households. Noorhassim I(1).

There is growing evidence of environmental causes of the disease, and substantial evidence of the role of the environment, especially inhaled agents such as allergens, pollutants, and viruses, in provoking asthma attacks.

Asthma is best thought of as an immunologically mediated disease, in which an abnormal immune response to inhaled agents provokes a cascade of events that lead to mucus hypersecretion, airways constriction and hyperresponsiveness, and, ultimately, symptoms. Because so much evidence points to environmental factors as triggers of the exuberant immune response, there has been much attention to identifying specific environmental factors that are most responsible for provoking asthma and developing strategies to minimize relevant exposures.

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Indeed, avoidance of environmental factors that provoke asthma, where feasible, is a logical way to improve asthma-related health and to minimize the need for long-term use of asthma medications. In this paper we will summarize available evidence on the current practices for managing environmental issues with patients who have asthma.

Though the potential scope of this paper on the environment and asthma could be quite broad and include topics such as primary prevention and occupational exposures, for the sake of brevity we will focus the discussion on common indoor and outdoor exposures that are most relevant to people in the United States, regardless of occupation. Also, though diet and infections may be conceptualized as part of the environment, discussion of those factors is beyond the scope of this paper.

Indoor and Outdoor Environments Management of asthma requires attention to environmental exposures that originate from both the outdoor and indoor environment, though, arguably, those originating indoors may be more relevant for certain patients with asthma.

Also, in contrast to the outdoors, people may have a greater ability to modify indoor environmental exposures. For example, most individuals do not have direct control over outdoor pollutant concentrations, but they may be able to decrease concentrations of specific pollutants in their homes.

Because the sources of exposure differ in the indoor and outdoor environments and because interventions to limit exposure also differ, we will consider the indoor and outdoor environments separately in the following discussion. Indoor Environmental Factors Air Pollution Indoor air pollution is a complex mixture of pollutants migrating indoors from outdoor air and pollutants generated by indoor sources.

Since studies have shown that indoor air pollution concentrations can greatly exceed outdoor air concentrations, 3 indoor sources can be very important contributors to total indoor air pollution. Table 1 lists some indoor pollutant sources relevant to asthma. Although the link between asthma and some indoor air pollutants has not yet been thoroughly studied, research to date suggests that they may play an important role in asthma morbidity.

Common air pollutants that exacerbate asthma include these: Ozone Sulfur dioxide from vehicles that burn fuels with a high sulfur content Particulate matter PM2.

The combination of higher levels of asthma-related air pollutants associated with changes in atmospheric conditions is expected to continue to increase the frequency of asthma attacks in people with asthma. These conditions may also increase rates of new onset asthma. Effects of climate change on asthma: Increases in levels of ozone and fine particulate matter can trigger inflammation of the lungs and reduce lung function, causing chest pain and coughing.

There is solid evidence that psychosocial stress contributes to the initial onset of asthma, especially when combined with other risk factors.

Stress can also trigger asthma in people with the disease. Stress can add to and even magnify the impacts of exposure to other environmental conditions that foster the onset or increase the severity of asthma.

For example, children in relatively low-income families who are also exposed to traffic-related air pollution are at greater risk of frequent asthma symptoms than children in the same neighborhoods whose families are financially better-off. Exposure to microbial diversity in the perinatal period may diminish the development of asthma symptoms.

relationship between asthma and the environment

Higher vitamin D intake during pregnancy is associated with decreased risk of wheeze in early childhood. Reduced risk of wheezing may be due to reduced frequency of respiratory infections. Broad exposure to a wealth of non-pathogenic microorganisms early in life is associated with protection against many health conditions.

Studies have found that first-year infants exposed to house dust high in levels of mouse, cockroach or cat allergens along with a variety of bacteria report significantly lower rates of allergies and recurrent wheeze at age three.

Various models for integrating clinical and non-clinical interventions have proven cost-effective, including community health workers providing in-home asthma education and environmental trigger reduction.

These include clinical interventions and interventions that reduce known risk factors for the development of the disease.

The relationship between prevalence of asthma and environmental factors in rural households.

Current priorities of the National Institutes of Health for clinical trials include these: Prevention of respiratory syncytial virus RSV and other early-life infections Immune modulation using prebiotics, probiotics, immunostimulants and animal exposure Prevention of allergen sensitization and allergic inflammation, using anti-IgE Environment and behavior Environmental, Behavioral and Social Interventions to Prevent Asthma Attacks and New Onset Asthma Preventing Asthma Attacks As noted above, reducing exposure to environmental triggers for asthma is a critical element of preventing asthma attacks for people with asthma.

Not everyone is sensitive to the same environmental triggers, but once an individual knows which triggers exacerbate her asthma, minimizing exposure is the best strategy. Preventing New-onset Asthma Because asthma is a multifactorial disease, the origins of which may vary from person to person, multifactorial interventions are likely to be most effective at preventing new onset asthma at both the individual and population level. A Cochrane review of seven studies targeting women at high risk of having a child who develops asthma concluded that nutritional interventions combined with environmental trigger reduction reduced the risk of the child developing asthma by 50 percent; the review also concluded that multifactorial interventions were more effective than single-factor interventions.

Avoid exercising near high-traffic areas. Find alternative routes to walk to school see our Built Environment webpage for more information.

Asthma Research and Resources — The Collaborative on Health and the Environment

Consider using a HEPA air filter in the home. Obesity Talk to a medical provider about weight-loss strategies that are best for you. Strategies include routine exercise, reducing the amount of fast foods and sugar-sweetened beverages in your diet and eating more fruits and vegetables. When exercising, avoid high-traffic areas.

relationship between asthma and the environment

Occupational asthmagens Federal safety laws require your employer to provide a safe and healthy workplace. If you feel that your workplace is unsafe and needs a confidential health and safety evaluation, you can contact OSHA or state departments of labor standards.

Environmental Issues in Managing Asthma

These risk factor-reduction recommendations are based on expert judgment about the strength of the evidence that particular risk factors contribute to asthma onset, along with thoughtful consideration about the pros and cons of taking action when there is inherent uncertainty about how risk factors interact with individual factors to cause disease.

However, individuals alone cannot control exposure to risk factors for asthma onset. Policy changes and program investments are needed to reduce environmental contaminants in workplaces, homes, schools and communities—with a particular focus on populations and neighborhoods that are disproportionately exposed—if we are to begin to reverse rising rates of new onset asthma.

relationship between asthma and the environment

Such initiatives will also benefit people already living with the disease. See more about environmental contributors to asthma in the list of CHE publications and Dig Deeper resources in the right sidebar. CHE invites our partners to submit corrections and clarifications to this page.

Please include links to research to support your submissions through the comment form on our Contact page.