Does how much money we earn affect cardiovascular health?
It is often expected that a person's income will constantly rise until they reach retirement age.
However, this isn't always the case. In fact, incomes have become so unpredictable that their volatility has reached an all-time high since 1980.
When a person's income fluctuates, it can alter many other factors in their life.
It can affect everything from mental health to diet, which could result in potentially serious health problems.
A new study suggests that personal income may even be associated with an increased risk of heart disease and death.
What is most surprising is that this link is present in relatively young people. We know this because an ongoing study has been tracking the health of young people living in four cities around the United States for nearly 3 decades.
The Coronary Artery Risk Development in Young Adults (CARDIA) study started in 1990. The four cities are Minneapolis, MN, Chicago, IL, Oakland, CA, and Birmingham, AL. Each participant was aged 23–35 years when the researchers first examined them.
The risk of low income
The researchers behind the new study analyzed data from the CARDIA study to see whether there was a link between income fluctuations and risk of cardiovascular events as well as death. They first studied income levels taken from five assessments in 1990–2005.
They defined income volatility as a percentage change from one income figure to the next. They also looked at income drop, or an income decrease of 25 percent or more from the previous assessment figure.
They then tracked the number of people who experienced cardiovascular events — both fatal and non-fatal — or died of any cause in 2005–2015.
There were 106 cardiovascular events and 164 deaths. The team took into account factors such as pre-existing heart risk and sociodemographic background.
The results, now published in the journal Circulation, found that substantial fluctuations in personal income were associated with a higher risk of death and cardiovascular diseases in the decade following this income change.
The highest levels of income volatility were linked with almost double the risk of death and over double the risk of conditions such as strokes, heart failure, or heart attacks.
These findings were all compared with those of people who fell into a similar category but who had less of an alteration in their personal income.
Some people were more likely to experience high income volatility. Such people included women, African-American people, those who are unemployed, people who are not married, people who smoke, those with less than a high school education, and people with signs of depression.
Why money matters
Lead study author Tali Elfassy, Ph.D., at the University of Miami Miller School of Medicine in Florida, says that income volatility "presents a growing public health threat, especially when federal programs, which are meant to absorb unpredictable income changes, are undergoing continuous changes, and mostly cuts."
"While this study is observational in nature and certainly not an evaluation of such programs, our results do highlight that large negative changes in income may be detrimental to heart health and may contribute to premature death."
Tali Elfassy, Ph.D.
It is not clear what exactly prompts income volatility to result in an elevated risk of cardiovascular problems, death, or both. It could be that fluctuations in a person's income result in unhealthful behaviors, such as excessive alcohol consumption, a lack of exercise, stress, and high blood pressure.
All of these things are linked to lifespan and cardiovascular health.
The researchers hope that other scientists will carry out further research to understand the cause of this newly found association. They list biologic and psychosocial pathways as being two potential reasons to explore.
They also see these findings as a way to more effectively screen people, especially those who are younger, for cardiovascular disease risk.
However, these results cannot currently be applied to all identities. Other ethnic groups and people living outside of cities will also need to be studied to see whether the same association is present.