Why People Live Longer in Some States

It has long been known that people live longer in some states than in others. With an average life expectancy of 78 years, Wisconsin rates as 14th best among the 50 states, behind Minnesota but ahead of Illinois and Michigan. By contrast, the average life expectancy in West Virginia and Mississippi is 71 years, at the bottom, while California and Hawaii have the highest life expectancy in the U.S.

The map below shows the average life expectancy of people who live in each of the 50 states. The darker the color the longer an average person lives.

Two generalizations are suggested by the map: states with lower poverty rates and higher Democratic vote shares seem to have higher life expectancy. This column looks more closely at these differences, how significant they are and what may account for them.

A person’s life expectancy is defined as the average number of years of life remaining to a person at a particular age and based on a given set of age-specific death rates—generally, the mortality conditions existing in the current period. When this column talks of life expectancy, it refers to the life expectancy at birth.

Life Expectancy By Gender

Women living in a state live longer than men in the same state, usually between five and six more years. States in which the average male life expectancy is longer than the average for all states also have female life expectancies that are longer than the average for all states.

The next graph compares male life expectancies for the 50 states, on the horizontal axis, to female life expectancies, on the vertical axis. The two closely correlate: a state in which men live longer than the average male American is also a state in which women live longer than the average female American.

Wisconsin is shown with the orange dot in the graph below. Wisconsin men have an average life expectancy of 75.2 years, compared to 80.5 years for Wisconsin women, a difference of 5.3 years.

The coefficient of determination, denoted as R2 in the chart above, is the proportion of the variation in the female life expectancy that can be predicted from the variation from the male life expectancy. In this case, the R2 of .9579 means that about 96% of a state’s variation in female life expectancy is predicted by the variation in the male life expectancy. The reverse would also be true.

Poverty’s Effect on Life Expectancy

The next graph plots life expectancy at birth in years, shown on the vertical axis, against the percentage of the population in poverty, on the horizontal axis. Wisconsin is again shown by an orange dot.

In general, life expectancy goes down as a state’s poverty rate goes up. The R2 in this case suggests that variations in poverty account for 69% of the variation in life expectancy. This is consistent with what we already know about the damaging effects of poverty on people’s health.

Partisanship and Life Expectancy

As the next graph shows, average life expectancy gets higher as a larger proportion of voters chose Kamala Harris over Donald Trump. In other words, the greater a state’s Republican share of the vote is, the shorter is its residents’ life expectancy. Swing state Wisconsin is near the middle in the percent Republican and above average in life expectancy. The R2 in this case is much lower and suggests that partisan views account for nearly 42% of the variation in life expectancy.

Putting It All Together

We’ve tested state life expectancies against the poverty rate and against the percentage of November’s vote that went Republican. What’s the effect of including both in the same model?

We re-ran the model using both poverty and the Republican vote: that resulted in an R2 of 80%, much larger than the R2 of either one alone.

As noted earlier, the negative effect of poverty is consistent with everything we know. The negative effect upon life expectancy of increased Republican vote share is more surprising. Going back a generation, to 1992, Democrat Bill Clinton carried poorer states like Louisiana, Arkansas, Kentucky and West Virginia. But these and other states with higher poverty rates are now more likely to vote Republican.

These poorer Republican states include nine that refused to expand Medicaid to eliminate the gap between their Medicaid and medical insurance purchased through the Affordable Care Act’s Marketplace. This has the effect of leaving some of their residents with no option for medical insurance.

Nearly every Republican state has also passed a Right-to-Work law, which undercuts unions and lowers average wages. And Republican states are are also more likely to have resisted the COVID-19 vaccines, which could cause lower life expectancy.

Whatever the causes, it’s clear that America’ red states have a lower life expectancy.