Consistent poverty linked to higher mortality rates

Key takeaways:

• In 2019, 10.5% of U.S. deaths were linked to cumulative poverty.
• Poverty was associated with 2.6 times as many deaths as drug overdose, 3.9 times as many deaths as suicide and 4.7 times as many deaths as firearms.

Poverty should be considered a major risk factor for death in the United States, according to the results of research published in JAMA Internal Medicine.

The United States consistently has a poverty rate much higher than similarly wealthy countries, which “presents an enormous challenge to population health, given that considerable research demonstrates that being in poverty is bad for one’s health,” David Brady, PhD, a professor of public policy at University of California, Riverside, and colleagues wrote.

Although previous research has offered “valuable contributions” on income and mortality, the researchers wrote that the quantity of mortality connected with U.S. poverty is unknown. So, they conducted a cohort study to estimate the associations between mortality and poverty and quantify the proportion of deaths linked to poverty.

Brady and colleagues evaluated the Panel Study of Income Dynamics 1997 to 2019 data merged with the Cross-National Equivalent File, ultimately including 18,995 respondents aged 15 years or older. The survey observed mortality from surviving family members and validated with the National Death Index. When it came to measuring socioeconomic status, the “higher quality household income measure” included all income sources and taxes and was adjusted for household size.

Brady and colleagues found that poverty was linked to a greater mortality hazard of 1.42 (95% CI, 1.26-1.6). Consistently being in poverty — referred to as cumulative poverty — was linked to a greater mortality hazard of 1.71 (95% CI, 1.45-2.02).

Current poverty was associated with 6.5% of deaths (95% CI, 4.1-9) among those aged 15 years or older in 2019. Among that same demographic, cumulative poverty was linked to 10.5% of deaths (95% CI, 6.9-14.4).

Current poverty was connected to higher mortality than major causes like stroke, accidents and lower respiratory diseases, according to the researchers. It was also linked to higher mortality than “far more visible causes,” they wrote. For instance, current poverty mortality was responsible for 2.6 times as many deaths as drug overdose, 3.9 times as many deaths as suicide, 4.7 times as many deaths as firearms and 10 times as many homicides.

However, cumulative poverty was linked to approximately 60% greater mortality than current poverty and higher mortality than obesity and dementia. The researchers wrote that the only causes or risks with greater mortality than cumulative poverty were cancer, smoking and heart disease.

“Because the U.S. consistently has high poverty rates, these estimates can contribute to understanding why the U.S. has comparatively lower life expectancy,” Brady and colleagues wrote. “Because certain ethnic and racial minority groups are far more likely to be in poverty, our estimates can improve understanding of ethnic and racial inequalities in life expectancy.”

Brady and colleagues additionally noted that disparities in survival between those in poverty and those not in poverty begin to emerge at around 40 years of age. The gap peaks around 70 years of age, they wrote, and then begins to converge again.

“The mortality associated with poverty is also associated with enormous economic costs,” the researchers wrote. “Therefore, benefit-cost calculations of poverty-reducing social policies should incorporate the benefits of lower mortality.”

Brady and colleagues also noted that “poverty likely aggravated the mortality impact of COVID-19, which occurred after our analyses ended in 2019.”

“Therefore, one limitation of this study is that our estimates may be conservative about the number of deaths associated with poverty,” they wrote. “Ultimately, we propose that poverty should be considered a major risk factor for death in the U.S.”