Make us your home page

Bay Buzz

The staff of the Tampa Bay Times

Study: Life expectancy for Tampa Bay’s poorest has dropped — but why?

Journal of the American Medical Association



A major new study about the relationship between income and life expectancy in the United States has unearthed this unsettling fact about the Tampa Bay area:

In Hillsborough, Pinellas, Pasco and Hernando counties, the life expectancy of the region’s poorest residents dropped by 2.2 years from 2001 to 2014.

For women with the lowest incomes in the area, that was a drop from a year or two over 80 to closer to 80. For the poorest men, life expectancy dropped from slightly above to slightly below 75.

This is just one finding, and the researchers didn’t flesh out the possible reasons for this particular local variation, in a study published in the Journal of the American Medical Association.

“The story really varies greatly across areas within America,” lead author and Stanford economist Raj Chetty said in a podcast on the journal’s web site. For the study, Chetty worked with researchers from from Harvard University, the Massachusetts Institute of Technology, McKinsey and Co. in New York City and the U.S. Treasury Department's Office of Tax Analysis.

The study says the relationship between income and life expectancy is well-established but is not well-understood.

Still, in the United States, an analysis of more than a billion death and income tax records between 2000 and 2014 showed that the life expectancy at the age of 40 is higher for people with higher incomes. People with the top 1 percent of incomes could expect to live 14.6 years longer than those in the bottom 1 percent.

Not only that, but over time, higher income groups saw their life expectancies go up over time.

“It is as if the top income percentiles belong to one world of elite, wealthy U.S. adults, whereas the bottom income percentiles each belong to separate worlds of poverty, each unhappy and unhealthy in its own way,” Nobel Prize-winning Princeton economist Angus Deaton wrote in an accompanying editorial for the journal.

The data showed that the relationship between what you make and how long you live varied a lot in different areas of the U.S. In some areas, differences in life expectancy between the richest and poorest have decreased since 2000, even as the poor nationally saw essentially no change during that time.

“Overall, when you look at the country as a whole, the gains in life expectancy have been much larger for the rich than for the poor,” Chetty said. On average, people in the top income quartile “have gained something like three years of life expectancy over the 2000s, whereas people in the bottom five percent of the income distribution have experienced no gain at all on average.”

“But,” Chetty added, “it turns out that this national story has a great deal of local variation to it. There are some places, like Birmingham, Ala., and Cincinnati, Ohio, where the poor gained almost as much in life expectancy as the rich. In contrast there are other places, like Tampa, Fla., and Knoxville, Tenn., where the poor actually had declining life expectancy over the 2000s.”

It’s disconcerting, said Troy Quast, an economist and associate professor in the University of South Florida's College of Public Health.

“I wouldn’t call it a shock, but I think it is a little bit surprising,” Quast said Monday. Many people might assume that the poor are a homogenous group, but the study shows that’s not the case from place to place.

The next important question, he said, is why.

“You just really don’t get any clear idea of what’s causing the differences in the Tampa Bay area,” Quast said. The relevant numbers for Hillsborough and Pinellas counties, he noted, are not too far from the national averages. One potential factor may be the surge in fatal drug overdoses since the turn of the century.

“Now the next step is … to try to go deeper into the data: What are the causes of death? What is driving the differences?” Quast said. It could be that a policy prescription does not emerge from the next level of inquiry, but that, instead, changes in behavior and culture prove to be more effective at addressing the local trend.

Chetty’s team found the strongest correlations for increased life expectancy for the poor in areas where low-income residents smoked less, exercised more and were less obese.

One strong correlation that shows up in all four Tampa Bay area counties is smoking, according to a New York Times effort to sift the study’s data for local trends. Nationwide, 26 percent of the poor smoke. Locally, the numbers range from 27.5 percent in Pinellas to 29 percent in Pasco.

Nationwide, the data provided weaker correlations to factors such as:

•  Health care access, such as the percentage of the population with health insurance, the number of primary doctors or other measures of the quality of health care.

•  Environmental factors like pollution and access to good food.

•  Labor market conditions such as unemployment rates.

“We generally find no significant association between those measures and levels of life expectancy for the poor,” Chetty said.

Along with the behavioral factors, the researchers also raised the idea that other factors like education and the possibility that poor health leads to reduced income (instead of poor income contributing to unhealthy living) could play a role in life expectancy.

“We end up concluding that individuals with low income tend to live longer in places where they have healthful behaviors, which tend to be cities like New York and San Francisco, which are … affluent cities with a highly educated population with lots of immigrants,” Chetty said. “The key question going forward is why, exactly, we see better health behaviors in low-income individuals living in such affluent cities. We leave that to future work.”

[Last modified: Monday, April 11, 2016 5:33pm]


Join the discussion: Click to view comments, add yours