The Relationship between Indoor Humidity, Fuel Poverty and Housing Conditions on Exacerbation, Symptoms and Lung Function of Patients with Moderate and Severe Chronic Obstructive Pulmonary Disease (COPD)

Author:
Organisation:
University of London
Date: 1998
Location:

Rationale

Chronic obstructive pulmonary disease (COPD) is a long-term degenerative condition that reduces the airflow into and out of the lungs. It remains a major challenge for health services; the level of mortality is far greater than that observed among asthma sufferers. Mortality among COPD patients is twice as high in summer as in winter, and the progression of the disease is much more rapid, suggesting the influence of seasonal effects. Earlier studies have described the negative impact of cold air and damp. It has also been proven that environmental pollutants (smoke, mould spores, chemical toxins, etc.) increase the risk of developing respiratory illnesses and aggravate existing cases.  

Householders in fuel poverty are more likely to be living in cold, draughty and/or damp homes, which are physically harder to heat and have unsatisfactory heating systems. The risks may be exacerbated by heating and/or ventilation strategies that compound the problem by increasing moisture levels or reducing the temperature. However, the exact effects of temperature and humidity (and the possible interaction between them) on residents with COPD have not been confirmed.  

Understanding the role that housing conditions may play in the epidemiology of COPD is crucial in allowing services to develop strategies that can reduce the risk factors and slow its progression. 





Key research Question

The study aimed to determine whether a positive relationship could be established between exposure to indoor cold, housing conditions and social support in the case of patients diagnosed with COPD.  



Summary of activity

Quantitative measurements were collected in the homes of 80 patients with moderate or severe COPD predominantly living in east London with an average age of 66. Technical measurements (e.g. temperature and humidity) were taken alongside medical tests (e.g. lung function), quality of life questionnaires and diary cards recording COPD symptoms. 

Structured interviews (surveys) using closed questions collected quantitative data from residents on the condition of their properties and their social support networks and energy spend. They also asked about property type and heating systems. Data from the study were then compared with existing figures for seasonal mortality and ongoing information on quality of life and health collected from the patients involved in the research.  

Statistical analysis was undertaken using STATA software. 





Findings

An intensification of certain COPD symptoms and an increase in the frequency of disease episodes were detected in individuals living in damp housing, which was far more prevalent in homes without central heating. Damp occurred more often in properties with low room temperatures and high humidity. The increase in specific symptoms suggests higher levels of bacterial infection, which were possibly the result of exposure to greater amounts of airborne particles. However, while an association could be demonstrated in the case of some symptoms it could not be linked to others.  

Higher frequencies of disease episodes were observed in those properties recording the lowest indoor temperatures, while lung airflow was influenced by humidity levels. Property type could be used to predict the aggravation of certain symptoms. The four factors that were related to respiratory health were the number of floors, number of rooms, age of the home and tenancy arrangements. A high number of rooms and more than one floor appeared to be associated with a lower prevalence of certain COPD symptoms. 



Recommendations

A more detailed study is necessary to demonstrate whether there are causal connections between humidity and COPD symptoms. Indoor heating should be the priority focus to address the housing conditions associated with COPD. Central heating and better internal wall insulation should be installed to reduce damp, and excess ventilation should be reduced. Residents should be encouraged to maintain a constant temperature in all rooms. 



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