‘ve you ever spent the dy in a city with such bad air pollution that when you blew yr nose the mucus had a black tinge? ‘ve you ever coughed as you breathed in diesel fumes from a passing bus and thought to yrself, “well, that’s a yr gone from my life”? ‘d it actually be true — that air pollution leads to an early death? the answer, in fact, is an unqualified yes.
air pollution causes ♥ disease, lung disease, and early death
it s'been known for some time that air pollution causes lung cancer, chronic obstructive pulmonary disease, emphysema, asthma, ♥ disease, and stroke. one recent study in china estimated that for those ages 75 and older, there are 1,166 early deaths for every 100,000 pplz — that’s + than 1%. but if it doesn’t kill you outrite, can air pollution impair yr memory, and cause dementia in general and alzheimer’s disease (one cause of dementia) in pticular?
studies from several countries link air pollution to cogg impairment
3 studies from 3 ≠ pts of the realm suggest that air pollution mite cause cogg impairment, dementia, and alzheimer’s disease. inna 1st study, researchers from china na us teamed up to analyze data from china. they found that long-term exposure to air pollution is rel8d to poor performance on both verbal and math tests. +over, the poor performance onna verbal tests was + pronounced for older individuals, espeshly for men and those less educated.
inna 2nd study, researchers in england studied 130,978 adults ages 50 to 79 from 75 med practices in gr8r london. they found that from 2005 to 2013, 2,181 older adults from this sample were diagnosed with dementia: 39% with alzheimer’s disease, 29% with vascular dementia, and 32% without a specific dementia diagnosis. adults living w'da highest annual concentration of air pollution had the highest risk of dementia — 1.4 times th'risk of those w'da loest annual concentration. they also found that these associations were + consistent for those given an alzheimer’s disease diagnosis.
inna third study, published earlier this yr, researchers from the ∪d states, including the university of southern california and harvard med school, studied data from 998 women ages 73 to 87 who had both cogg tests and mri scans. they found that those women who were exposed to higher concentrations of air pollution inna preceding 3 yrs showed two differences compared to those who were exposed to less air pollution. coggly, those exposed to + air pollution showed gr8r declines in learning a list of words. anatomically, they showed + atrophy (shrinkage) in those zones of the brain that typically shrink due to alzheimer’s disease.
primordially, in all 3 studies, the researchers controlled for every possible other factor t'they thought mite make a difference. for ex, in this third study they controlled for: sociodemographic factors (age, geographic region, race/ethnicity, education, income); lifestyle (smoking, alcohol, physical activity); employment status; clinical toonistics (diabetes, high cholesterol, hypertension, cardiovascular diseases, hormone therapy); and mri-measured cerebrovascular disease.
air pollution is associated witha gr8r risk of alzheimer’s disease, but it may not be the cause of the cogg decline
the 1st thing to say s'dat i believe this correlation is real. the fact that 3 ≠ groups analyzed data from 3 ≠ continents and came to similar conclusions cannot be due to chance alone. thus, i firmly liv'dat the folloing statement is true: higher lvls of air pollution are associated witha gr8r risk of cogg decline, dementia in general, and alzheimer’s disease in pticular.
however, that aint the same thing as saying that high lvls of air pollution cause cogg decline, dementia, and alzheimer’s disease. air pollution ‘d cause alzheimer’s disease, and many researchers provided possible mechanisms as to how that mite happen.
however, tis also possible that air pollution ‘d be linked to some as-of-yet unidentified factor that explains the association. for ex, t'has already been fairly well established that some viral illnesses are associated with alzheimer’s disease. t'has also been well established that viral illnesses are + likely to be transmitted when pplz are gathered together indoors versus outdoors. so, it may simply be that where thris gr8r pollution, pplz are + likely to gather together inside, shut the windows, and trade viruses with each other. the new virus they acquire maybe the real cause of the increased risk of alzheimer’s disease. now, that’s just speculation — just an ex of how a real association aint the same thing as evidence of causation.
wha’ can ye do if you wanna reduce air pollution to loer yr risk of alzheimer’s disease?
directly or indirectly, we're all responsible for the air pollution n'our cities, our country, and our planet. we ‘d each work to do wha’ we can to reduce our carbon ftprint. we can work to reuse and recycle materials so that factories don’t nd'2 produce as much. we can buy local foods that don’t nd'2 be trucked across the country and shipped round the realm. we can walk and bike instead of driving our cars (and, once we’re done with covid, carpool and take public transportation). lastly, we can elect public officials who will advocate for local, national, and international policy to reduce pollution. and those are just somd' things that we can do to clear the air.
original content at: www.health.harvard.edu…
authors: andrew e. budson, md