The non-linear risk of mortality by income level in a healthy population: US National Health and Nutrition Examination Survey mortality follow-up cohort, 1988–2001
2008

Income and Mortality Risk in the US

Sample size: 11733 publication Evidence: high

Author Information

Author(s): Rehkopf David H, Berkman Lisa F, Coull Brent, Krieger Nancy

Primary Institution: Harvard School of Public Health

Hypothesis

The study aims to describe the non-linear risks of all-cause and cause-specific mortality across the income distribution.

Conclusion

Most income-related mortality risk is found among individuals with family incomes below the median.

Supporting Evidence

  • Risk of mortality decreased with increasing income levels only among persons whose family income was below the median.
  • Above the median income level, there was little decrease in mortality risk with higher income.
  • The study found significant non-linear risks of all-cause mortality across different income levels.

Takeaway

People who earn less money are more likely to die, especially if they earn below a certain amount, which is important for helping those in need.

Methodology

The study used data from the US National Health and Nutrition Examination Survey and analyzed mortality risk using proportional hazard models with penalized regression splines.

Potential Biases

Potential residual confounding may affect the observed associations between income and mortality.

Limitations

The study's income data lacks specific categories above $50,000, and income was measured at only one point in time.

Participant Demographics

Participants were US adults aged 18-64 at baseline, with a follow-up period of up to 13 years.

Statistical Information

P-Value

<0.001

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1186/1471-2458-8-383

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