WP 1.5 Health Description Air pollution is a significant cause of morbidity and mortality. The greatest health impacts fromair pollution worldwide occur among the poorest and most vulnerable populations. The amount of exposure in terms of the number of people, exposure intensity and time spent exposed is far greater in the developing world (1); approximately 76% of all global particulate matter air pollution occurs indoors in the developing world. When attention is focused on the problem of indoor air pollution resulting from the use of ‘biomass fuels’ (BMF), an enormous health burden is uncovered. There is now evidence linking an increased risk of respiratory tract infections, exacerbations of inflammatory chronic disease, cardiac events, stroke, eye disease.
- As regards respiratory disease, there is a increasing amount of evidence of a high incidence of chronic obstructive pulmonary disease (COPD) among people exposed to high level of indoor pollution; women and children who spend most time near the fireplace especially during the winter month in the mountain region, are the most affected. Even if the link between indoor pollution and COPD seems rather clear, all the subject studied in the previous papers were also exposed t cigarette smoking and outdoor environmental pollution. The main methods to assess respiratory health is the measure of respiratory function by means of spirometry. This a simple, non invasive method test which can be easily performed by subjects older than 6 years old. Another important method is the administration of validated questionnaire about the presence of respiratory symptoms and the impairment of respiratory health.
- Particulate air pollution is statistically and mechanistically linked to increased cardiovascular disease. Long-term prospective cohort studies show an association between levels of air pollution consisting of fine particulate matter and an elevated risk of death from all causes and from cardiovascular disease. More recent data have shown that non-fatal ischemic events are also associated with an increase in fine particulate concentrations in the community. There is a paucity of data on the association between cardiovascular disease and BMF, but it is known that particulate air pollution leads to rapid and significant increases in fibrinogen, plasma viscosity, platelet activation. It was demonstrated that chronic exposure to elevated PM2.5 was associated with increased levels of circulating endothelin (ET)-1 and elevated mean pulmonary arterial pressure in children living in Mexico City. Recently, biomass smoke in Guatemalan women has been shown to increase diastolic blood pressure. Therefore, it is highly likely that BMF represents a considerable risk to cardiovascular health. Non-invasive measures of atherosclerosis have emerged as adjuncts to standard cardiovascular disease risk factors in an attempt to refine risk stratification and the need for more aggressive preventive strategies. Two such approaches, carotid artery imaging and brachial artery reactivity testing are ultrasound based.
The population of high altitude villages is a unique sample to study the effect of the only indoor pollution. In fact, the absence of traffic, due to the lack of roads, and the very low level of smoking habits allow to have no other confounding factors We hypothesize that the chronic exposure to indoor pollution:
- can accelerate the physiological respiratory function decline, (usually estimated around 15-20mL/year in healthy subjects) and induce bronchial obstruction in a higher percentage of subjects.
- can induce cardiovascular impairment. We plan to study respiratory and cardiovascular health in the high altitude villages in Khumbu Valley were, beside indoor pollution, an outdoor pollution monitoring is also available.
An estimated 400-500 subjects will be studied by non invasive test such as: Spirometry to test respiratory function, Six minutes walking test to assess exercise capacity, Carotid artery ultrasound scan to evaluate indices of local arterial stiffness (compliance, distensibility) Endothelial function assessment (in the brachial artery) non invasive Systolic pulmonary pressure evaluation.
Aims Our aim is a longitudinal study in the population of Khumbu Valley, in particular divided in two parts:
- to study after two years the same sample of population in Thame in order to: a) to assess the respiratory function decline by means of spirometry and the respiratory health by means of questionnaire and six-minute walking distance; b) to detect the presence of markers of early atherosclerosis with ultrasound and to estimate the value of systolic pulmonary pressure in comparison with not exposed subjects.
- to study respiratory and cardiovascular health (spirometry, six minute walking distance, questionnaire, ultrasound) in the dwelling of Khumbu Valley villages.
All data will be related to indoor and outdoor pollution information.
Activities Indoor air pollution
Data on indoor air quality and inhabitants’ respiratory health status were collected in November-December 2008 in 35 households in the village of Thame and surroundings, where 105 individuals over 14 years of age were sampled. The kitchens of most private houses in are equipped mainly with open fireplaces for cooking (and heating in winter), known as “traditional cooking stoves” fuelled by wood. Due to the lack of a chimney or other fume outlet, these facilities emit fumes directly into the kitchen area.
Respiratory Function
Exposure to high concentrations of CO due to fuelwood combustion is the major causes of development of chronic obstructive pulmonary disease (COPD). The spirometry tests indicated that the majority of the population sampled (82%) had no respiratory obstruction; however 13% had mild and 5% moderate obstruction. Due to the lack of a reversibility test, we could not discriminate between asthma and COPD. Notably, out of the 18% of the population with pulmonary obstruction 71% were women (less than one third were males). The percentage of females with probability of COPD was higher than expected in the general population (between 4 and 10%). These results imply that the female population runs a higher risk of being affected by respiratory diseases, particularly COPD, because they spend more time in the kitchen and are thus more affected by indoor air quality (IAQ).
Partner Publications Click HERE for WP 1.5 Publications.
|
|