Socioeconomic status (SES) is a measure of social status based on one’s level of poverty or wealth. SES has been associated with mortality in many studies. This MIDUS study looked at whether the different ways SES is measured matters when predicting mortality. Many studies have used measurements of annual income, status of one’s occupation, or one’s highest level of education, to determine SES. This study looked at how SES is related to wealth, a measure of net worth.
Wealth is calculated by:
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- totaling the amount of money a person has if they included all their assets (funds in their bank accounts and value of their homes, cars, other real estate, stocks & bonds, and other high-priced possessions)
- then subtracting all their debts (loans, mortgage, credit cards).
Those with no wealth have debts that are greater than their assets.
Few studies have looked at the association of wealth with mortality over the life course. However, the importance of how SES is measured may vary by life stage:
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- In early adulthood, as individuals start developing their careers, one’s amount of education is likely the strongest indicator of SES.
- Later, when one is more likely to be able to purchase a home, wealth increases, and may be a better indicator of SES.
- After retirement, education and income are no longer as significant. Rather, it is one’s accumulated wealth that dictates SES, so is most likely the most important determinate of mortality.
This study included 6320 respondents from MIDUS 1, aged 25-74, who answered survey questions about their wealth in 1995-1996. One thousand of them had passed away by 2013. Results showed that mortality rates did generally decline as wealth increased, but not at a steady rate:
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- The first $50,000 of wealth accumulation reduced mortality by 22%.
- Between $50,000 and $299,999 of wealth, there were no significant differences in mortality rates.
- Those with $300,000 to $499,999 in wealth had 41% lower mortality than those with $200,000 to $299,999.
- Having more than $500,000 did not bring any improvement in mortality– it did not increase longevity compared to those with $300,000 to $499,999.
Other results showed:
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- The probability of surviving from age 25 to 75 years was 66% for those with no wealth (zero assets or in debt) vs. 86% for those with at least $300,000 in wealth.
- After age 65, the disparities in mortality were larger when measured by wealth than by education, occupation, or income.
- Among those with no assets there was a 51% chance in surviving from age 65 to 85 vs. a 70% chance of survival for those with at least $300,000 of wealth. The gaps by other SES-related measures (education, occupation, income) were much smaller.
These results included adjustments for other factors that may affect wealth and/or mortality. This included severe illness, which can destroy savings. In this study, analysis showed:
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- Among those with 3 or more hospitalizations in the past year, 52% had zero assets. Only 29% of those with no recent hospitalizations had zero assets.
- Hospitalizations within the past 12 months were associated with higher mortality.
- Once researchers controlled for hospitalizations, the association between wealth and mortality became notably smaller.
Additionally, wealth is not randomly distributed. For example, marriage tends to increase wealth if both partners are working:
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- Among those who were married, 14% had at least $300,000 in assets, whereas only 5% of those who were single had that much wealth.
- Consequently, adjustment for marital status decreased the association between wealth and mortality.
After adjusting for all factors, there was still a notable difference in wealth disparity in mortality after age 65. However, while accounting for 57 economic, behavioral, social, and psychological factors, researchers found that smoking history had the strongest association with mortality. It was more significant than any SES measure:
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- After age 65 years, current smokers had triple the mortality rate than never smokers.
- Current smokers had a 33% chance of surviving from age 65 to 85, vs. a 70% chance for those who had never smoked, which is a difference of 37 percentage points.
- The differential in mortality between the poorest and wealthiest categories was only 19 percentage points (51% vs 70%).
This suggests that even if we have limited opportunities to increase our wealth, we may significantly increase our chances of living longer by stopping smoking or by never starting.
Source: Glei, D. A., Lee, C., & Weinstein, M. (2022). Assessment of mortality disparities by wealth relative to other measures of socioeconomic status among US adults. JAMA Network Open, 5(4), Article e226547. https://doi.org/10.1001/jamanetworkopen.2022.6547
Read the full article at: http://www.midus.wisc.edu/findings/pdfs/2488.pdf