A high concentration of aerosolized particles in the air can increase the likelihood of senile dementia. This conclusion was made by scientists following a study of 4 thousand elderly residents of Seattle. The results of their research were published in the scientific journal Environmental Health Perspectives.
"If the mass of aerosol particles in a cubic meter of air increases by one microgram, the likelihood of dementia in older people increases by about 16%. This was typical for both Alzheimer's disease and other forms of senile dementia," said Rachel Schaffer, one of the study authors, researcher at the University of Washington.
The World Health Organization estimates that about 7 million people die each year due to air pollution by carcinogens and other harmful substances. Many researchers believe that, in fact, there could be many more such deaths. Scientists have yet to reach a consensus on which types of air pollutants are particularly harmful to the health of people and pets.
Among them are, in particular, various aerosol particles that enter the air of large cities as a result of the interactions of exhaust gases, water and sunlight. Typically, these microscopic droplets linger in the lower atmosphere for two to three weeks. Thanks to this, they can spread quite widely and penetrate into the human body.
By studying air samples collected from long-term health observations of elderly residents of Seattle and surrounding areas, Schaffer and her colleagues found that aerosol particles play an unexpectedly large role in the development of various forms of senile dementia.
The first study began in the late 1970s, the second in the early 1990s. More than 4 thousand elderly volunteers took part in them. Approximately 25% of them have been diagnosed with dementia over the decades of observation.
Due to the fact that the research lasted long enough, scientists have determined a statistical relationship between the likelihood of developing dementia and the amount of aerosols in the air in Seattle. On average, with an increase in the typical mass of aerosol particles by one microgram in each cubic meter of air, this probability increased by 16%.
Based on this, the researchers believe that the likelihood of senile dementia is influenced not only by variations in gene structure, diet and level of physical activity, but also by air quality. This should be taken into account by the medical and urban services of countries in which the concentration of aerosols in the atmosphere of cities is especially high, Shaffer and her colleagues summed up.