Can politics kill you? Research says the answer increasingly is yes.

As the coronavirus pandemic approaches its third full winter, two studies reveal an uncomfortable truth: The toxicity of partisan politics is fueling an overall increase in mortality rates for working-age Americans.

In one study, researchers concluded that people living in more-conservative parts of the United States disproportionately bore the burden of illness and death linked to COVID-19. The other, which looked at health outcomes more broadly, found that the more conservative a state’s policies, the shorter the lives of working-age people.

The reasons are many, but, increasingly, it is state — and not just federal — policies that have begun to shape the economic, family, environmental, and behavioral circumstances that affect people’s well-being. Some states have expanded their social safety nets, raising minimum wages and offering earned income tax credits while using excise taxes to discourage behaviors — such as smoking — that have deleterious health consequences. Other states have moved in the opposite direction.

Researchers say the result of this growing polarization is clear: The nation’s overall health profile is going from bad to worse. Americans can expect to live as long as they did in 1996 — 76.1 years, with life spans truncated by higher rates of chronic illnesses, deaths in childbirth and COVID.

“I’m not doing this research to be partisan, simplistically supporting one party or another,” said Nancy Krieger, a social epidemiologist at the Harvard T.H. Chan School of Public Health and a co-author on one of the two studies. “This is about looking at the behavior of different actors, some of whom have a lot more power than others to set standards, make demands, and allocate resources.”

Krieger said it is fair for people to ask their elected officials, “Are you doing what you should to protect our health?”

Harvard researchers analyzed data on COVID-19 mortality rates and the stress on hospital intensive care units across all 435 congressional districts from April 2021 to March 2022. They also examined congressional members’ overall voting records, how they voted on four coronavirus relief bills, and whether the governor’s office and legislature of a state were controlled by one party.

The study, published this month in the Lancet Regional Health-Americas, found that the more conservative the voting records of members of Congress and state legislators, the higher the age-adjusted COVID mortality rates — even after taking into account the racial, education, and income characteristics of each congressional district along with vaccination rates.

COVID death rates were 11 percent higher in states with Republican-controlled governments and 26 percent higher in areas where voters lean conservative. Similar results emerged about hospital ICU capacity when the concentration of political power in a state was conservative.

The findings cannot be explained away as features of the economic and social conditions of the people who live in various congressional districts, Krieger said. This is “somehow above and beyond the demographics of the district [that members] represent. It’s suggesting that there is something going on through political processes associated with the political voting patterns of elected officials,” she said.

Public policies — along with public opinions about masks and vaccines and a constellation of other factors — helped change the nation’s pattern of COVID mortality.

A Washington Post analysis of COVID data from the Centers for Disease Control and Prevention from April 2020 through this summer found the age-adjusted death rates for COVID shifted. Early in the pandemic, communities of color — especially Black people — disproportionately bore the burden. But by mid-October 2021, that pattern had shifted, with the death rate for white Americans, who form the core of the Republican base, sometimes eclipsing that of other groups.

And still, the unequal burden of death and disease transcends COVID: A chasm of inequality puts communities of color at higher risk of chronic conditions that leave immune systems vulnerable —a reflection of systemic racism, public health experts say.

“Too often, public health and medical behavior is understood to be individual-level behavior. Politicians behave. Institutions behave,” Krieger said. “If your congressional representative is encouraging you to wear masks or not wear masks, those are very different messages.”

The division in American politics has grown increasingly caustic and polarized, but it wasn’t always this way.

From the 1930s to the 1970s, there were major investments to improve the lives of vulnerable people nationwide. The Social Security Act of 1935, Medicare and Medicaid in 1965. Before these federal programs, the nation was a hodgepodge of state programs that varied widely, said University of Washington political scientist Jake Grumbach, a co-author of a study on the effects of state policy on the mortality of working-age adults published in October in the journal PLOS One.

Everyone saw benefits, but the federal legislation from earlier decades “pulled the poorer states up faster,” Grumbach said, adding that “you saw a convergence between states” in terms of health outcomes.

Then came the breakdown of the New Deal coalition. The nationalization of media. Increased money in politics. And the social upheaval of the 1960s and ‘70s —- the civil rights movement, the women’s movement, the sexual revolution, environmentalism.

“All of those things contributed to polarization,” Grumbach said, adding that the rupture began “kicking up in the ‘90s” and has really taken hold since 2010, an era that “saw the real radicalization of the Republican Party . . . that culminated with Trump.”