The study was published in the American Economic Review, a peer-reviewed journal.
“There’s a substantively important causal effect of where you live as an elderly adult on mortality and life expectancy across the United States,” study co-author Amy Finkelstein, professor in MIT’s Department of Economics, said in a news release.
Researchers analyzed Medicare records from 1999 to 2014 for the study. They focused on 6.3 million Medicare beneficiaries between the ages of 65 and 99. Around 2 million people moved from one U.S. “commuting zone” to another. The other estimated 4.3 million were a random 10% sample of people who didn’t move during the 15-year period.
A crucial study aspect was looking at how different people from the same locations progressed when they moved to different places.
“The idea is to take two elderly people from a given origin, say, Boston. One moves to low-mortality Minneapolis, one moves to high-mortality Houston. We then compare how long each lives after they move,” Finkelstein said.
Although people have varying health profiles, the study’s Medicare records had detailed claims data. Using that, researchers used records of 27 different illnesses and conditions to categorize older adults’ general health. Conditions included diabetes, lung cancer and depression. Researchers also tried to account for pre-existing health levels of people from the same location who moved to different places.
Additionally, researchers estimated what fraction of people’s health conditions they didn’t see. They also reviewed how health varies among people from the same location who move to different places. Estimates were adjusted for differences in unobserved and observed health.
Ultimately, the study showed cities on the East and West Coasts — including New York City, San Francisco and Miami — positively affect longevity. Positive outcomes were found for some Midwestern metro areas, too, such as Chicago. In much of the deep South, however, longevity was poorly affected. This included the majority of Alabama, Arkansas, Louisiana and northern Florida. The bulk of the Southwest had a similar outcome. That included portions of Texas, Oklahoma, New Mexico and Arizona.
Researchers welcome more studies to see why different places have different effects on longevity.
“Differences in health care across places are large and potentially important,” Finkelstein said. “But there are also differences in pollution, weather, (and) other aspects. What we need to do now is get inside the black box of ‘the place’ and figure out what it is about them that matters for longevity.”
For more on the study, see the complete news release here.
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