Young adults who struggle to make ends meet and are in precarious employment are at increased risk of death and heart attacks, strokes or heart failure.
Those aged 23 to 35 who suffer fluctuating income face nearly double the risk of death and more than double the risk for cardiovascular diseases within the next decade compared to those with a stable income.
And women and African-Americans were more likely to experience high income volatility and income drops than white men, the US study found.
The study suggested bouts of poverty when young people should be earning more affects heart health more than previously thought and they should be screened to spot the first sign of poor health.
And it is likely that there are specific psychosocial and biologic pathways through which income volatility is associated with CVD and premature death.
The study noted while from young adulthood through midlife, most individuals experience at least some increases in income.
But almost half experiencing at least some decreases in income and fluctuating income is more common among individuals who experience drops in income.
Lead author Assistant Professor Dr Tali Elfassy at the University of Miami Miller School of Medicine in Florida said in the US the recent rise in income inequality suggests that a larger proportion of the population faces poverty and economic difficulties.
While most people experience some income change, income volatility has been on the rise and has reached a record high level since 1980.
Prof Elfassy said: “Income volatility is generally considered to be a sudden and unpredictable change in income over time, and most often it consists of declines in income.
“The rise in income volatility is especially true for low income households who experience a significant number of income drops that exceed 25 per cent of their
average income and presents a growing public health problem.
“Income volatility may have pervasive effects on health, potentially mediated by behavioural changes, psychological stress, or access to medical care.
“Increasing evidence suggests income volatility is associated with an array of unfavourable health outcomes, including worse mental health, overall health
quality, and all-cause mortality.
“Income volatility may also play a role in acute or chronic health outcomes for example, low income patients with chronic diseases may give up medications and medical visits to cope with unexpected financial instability, consequently resulting in increased risk of disease, including heart attack and stroke.”
So the study analysed data from the ongoing Coronary Artery Risk Development in Young Adults (CARDIA) study which began in 1990.
It is following 3,937 people living in Birmingham, Alabama; Minneapolis, Minnesota; Chicago, Illinois; and Oakland, California.
Changes in income were recorded in five assessments from 1990 to 2005.
They measured income volatility as the percent change in income from one measurement to the next, and income drop as a decrease of 25 per cent or more from the previous assessment.
Between 2005 and 2015, the researchers assessed fatal and non-fatal cardiovascular events and all causes of death using medical records and death certificates.
Those who had the biggest fluctuations in personal income were significantly more at risk, scientists found.
And income volatility and income drops experienced in early to mid-adulthood are important independent predictors of CVD risk and overall mortality.
Low wages may lead to unhealthy behaviours such as drinking, smoking or not exercising while juggling the finances may increase stress and blood pressure which is known to affect heart health.
Previous studies in Australia and Sweden found long-term falling wages was linked to poorer mental health and physical health.
Prof Elfassy said: “Income volatility presents a growing public health threat, especially when federal programmes, which are meant to help 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 programmes, our results do highlight that large negative changes in income may be detrimental to heart health and may contribute to premature death.”
The study was published the American Heart Association’s journal Circulation.
By Tony Whitfield