Green Environments Linked to Longer Lives

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A large study of American women found lower mortality rates among those whose homes are surrounded by vegetation.

By Tom Jacobs

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(Photo: CSeeby/Flickr)

Many studies have linked exposure to nature with higher levels of physical, mental, and emotional health. But the question remains whether these benefits are peripheral to one’s overall health, or genuinely important in the long run.

Well, there’s no more telling indicator than the length of one’s life. And, using that metric, living in a home that is surrounded by green space matters enormously.

A large, longitudinal study of American women found those who live among abundant vegetation had a 12 percent lower mortality rate than those with little or no exposure to nature (excluding accidental deaths). The largest differences were found in rates of death from cancer, respiratory diseases, and kidney disease.

“Findings were consistent across all regions of the U.S., as well as in urban and rural areas,” reports a research team led by Harvard University epidemiologist Peter James. “We observed no threshold at which greater greenness exposure was not associated with lower mortality rates.”

Time spent in the company of grass and trees can literally be a life preserver.

These results, published in the journal Environmental Health Perspectives, are consistent with those of similar studies conducted in England and Canada. “While planting vegetation may mitigate effects of climate change,” the researchers write, “it also might be used to improve health.”

James and his colleagues used data on 108,630 participants in the Nurses’ Health Study, which examines risk factors for chronic diseases among women. It specifically traced participants between the years 2000 and 2008, who filled out questionnaires every other year.

Participants provided information on a variety of factors that can influence health, including their body mass index, frequency of exercise, history of smoking, mental health (including depression), and level of “social engagement.”

Vegetation around their homes was measured using satellite imagery. The researchers used two measurements: greenery within 250 meters (273 yards) of the home, and within 1,250 meters (about three-quarters of a mile). The latter figure indicates the greenness of the environment one would encounter taking a 10- to 15-minute walk.

The researchers noted all deaths from non-accidental causes over the eight years and placed them into categories including infectious diseases, heart disease, respiratory disease, and stroke.

The results were striking. “Higher levels of greenness around each participant’s address were associated with lower rates of all-cause, non-accidental mortality,” the researchers write, “regardless of adjustment for age, race/ethnicity, smoking, and socioeconomic status.”

Those with the highest levels of vegetation around their immediate home had a 12 percent lower mortality rate than those at the lowest level. “Results were similar for the 1,250 meter radius, although the relationship was slightly attenuated,” the researchers write.

This is partly explained by the fact that those living in green surroundings tended to be more social, and in better mental/emotional health (with lower levels of diagnosed depression and antidepressant use). Playing a smaller but still significant role: They exercised more than people with less access to the natural world, and were exposed to less air pollution.

“These findings suggest that green vegetation has a protective effect,” James and his colleagues conclude, adding that they suggest the value of “policies to increase vegetation in both urban and rural areas.” Indeed, it’s hard to think of a health-boosting intervention that is more of a bargain.

So, if the view from your picture window isn’t dominated by green, get thee to a nursery. It seems time spent in the company of grass and trees can literally be a life preserver.

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