I was puttering around tonight looking at life expectancy, and I happened to come across this table in a paper from a few years ago:
At the top, smoking and obesity matter a lot. This is not big news.
In the middle you have a bunch of stuff that's fairly close to a zero correlation. Some of them might matter, but not a lot.
Then, hidden at the bottom under "Other Factors" are several things that obviously make a big difference. Mostly they're related to higher incomes, which matters a lot within the poorest slice of society. There's a big difference between the life expectancy of someone at the very bottom, living on the street, and someone who's a little higher up, living in a lousy apartment with at least enough income to eat regularly and see a doctor occasionally.¹
The highest correlation is with the number of immigrants living in a neighborhood. The authors don't say much about this, and it turns out that's because this is common knowledge among demographers. Here's a more recent study:
In 2017, foreign-born life expectancy reached 81.4 and 85.7 years for men and women, respectively. That’s about 7 and 6.2 years longer than the average lifespan of their U.S.-born counterparts.
“Demographers knew that immigrants lived longer. The main question that we set out to answer was, ‘How much is this really contributing to national life expectancy trends?’” said Arun Hendi, the lead author of the study.
....Research shows that the difference between immigrants and the U.S.-born has widened substantially over time....“The fact that immigrants are doing well suggests that there is a capacity to thrive in the U.S., but the U.S.-born aren’t fulfilling that potential,” he said.
This is new to me, and I don't have anything insightful to say about it. It's just something to ponder over.
¹Income matters even more between the poor and the rich. We've known for a long time that this is probably the single biggest factor in longevity. Rich people have life expectancies nearly a decade longer than poor people.
Perhaps the study accounts for this, but the foreign born cohort would likely not include anyone who died in early childhood. If I remember correctly, the US has a surprisingly high child mortality rate when compared to other advanced countries.
I wondered this too. Immigrants have already survived to the age at which they immigrated.
Good point. Seems like the researchers could factor this out pretty easily but they do not mention it in the paper.
Additionally for the most part healthy folks immigrate so there's a fair amount of self selection there too.
OTOH, you'd expect that immigrants living in poor neighborhoods (hence, working low-paying jobs) are exposed to lots of deadly and dangerous conditions -- things that would hit their health and longevity.
But not from birth, immigrants may start healthier.
The more recent study specifically says life expectancy at birth (the default anyway). This would necessarily include infant mortality. But if some of the people are dying in infancy, how could they be immigrants in the US? Something is fishy.
Families immigrate. I happen to know this because I changed country of residence at the age of 10 days. I would expect that babies would be a higher proportion of arriving immigrants than of the domestic population.
I think it's been noted that immigrants reproduce far in excess of native-born. And then their native-born children rapidly revert to the mean.
Besides the sampling bias from excluding those dying in infancy, I suspect that immigrant neighborhoods might exhibit a stronger sense of community, which provides the benefits of social relationships (already demonstrated as a strong factor in ensuring health) and also mutual support and assistance — for example, caring for a sick community member by bringing food, transportation help to doctor, wellness checks, etc.
One other thing, US born poor....how many are there due to health issues? The opioid epidemic also hit rural/small cities/rust belt (typically US born) areas pretty hard.
Not to mention that immigrants may not be as impacted by the same cultural rot that afflicts US-born people who are poor. Things such as eating lots of domestic junk food, having lived in poor conditions for life, having been born to poor parents - these things may not apply to immigrants to the same degree as the US-born. Short version: the poor in the US may be more affected by the generational nature of being poor.
Immigrants may have a better social support network to facilitate a healthier lifestyle than US-born people who are poor do, such as healthier grocery shopping.
Despite what Trump said, they are sending us their best. What kind of people are likely to move to a strange land away from home? Those with the energy and initiative to do it. They're likely to be healthier to begin with (bad health saps your initiative) and take better care of themselves. So they tend to live longer than the people already here, even though they are just as poor.
They also have likely avoided being trained to eat the American diet--extremely high salt, processed foods, animal protein. Yes, obesity catches much of this effect but not all of it.
US culture and society is incredibly toxic and unhealthy. Psychologically, nutritionally, etc. Immigrants still have their more effective cultures.
Be interesting to compare the life spans of immigrants matched to those who remained in the source country. Be very hard to do, of course, but might indicate whether we're getting the fittest/best who thrive here.
I'm not seeing anything related to for lack of a better term 'family closeness'. I suspect but cannot prove that large close-knit familys offer emotional support and backup that is quite often lacking in your typical 'American' family.
There is data about marriage: https://www.census.gov/library/stories/2021/05/marital-histories-differ-between-native-born-and-foreign-born-adults.html
Immigrants tend to marry later, and then stay married compared to the native-born. That stability likely provides some benefit.
My observation is that family closeness can cut both ways. I used to be counsel for the local child protection authorities, and noted that despite a fairly large local population of East Indian extraction, there were never child protection issues with East Indian children. It appears that if a mother is not able to properly care for her children, there is an aunt, or a grandmother, or a cousin, or SOME relative, ready to step up and make sure the children don't suffer.
The flip side is that those same families have, compared to the general population, a horrifyingly high domestic murder rate. Sometimes, the closeness can be too close.
The chart says '% of immigrants', does that mean it's just the immigrants themselves living longer or that their presence increases the welfare generally?
Immigrants do not eat as much of the standard American diet as non-immigrants, which should extend their lives in comparison.
I used to use this as an example in my Statistical thinking class to talk about correlation/causation -- what is it that gives this result. Previous comments have mostly brought up the reasons we came up with.
The culture?
Among Korean War UN POWs, Turkish soldiers had the best survival rate. One reason cited was their peasant communal culture meant they all looked out for each other. American sturdy individualists, OTOH . . .
I learned about this in a class, I think on aging. The reasons as mentioned above--healthy people with initiative choose to immigrate, they do not eat the standard American diet. As they adopt our diet, life expectancy decreases.
Immigrants were exposed to less lead as children, obviously. 😉
This is one of those papers that deserves a follow-up with the authors. Scientists are typically pretty open to answering (reasonable) questions about their research.
For what is worth, the 'Shazam' section relates only to the bottom income quartile--Not the whole population. Do ethnic enclaves support higher quality food accessibility for everyone?
Kevin, do you venture into your own 'comments' section? Can you collate these questions and follow up?