Decades of research have informed us that higher socioeconomic status often equates to better overall health.
But what about people who were not born with high socioeconomic status, but earn it later in life? According to a new study, even people who eventually land at the top of the socioeconomic ladder may not reap the same health benefits as those who were born there.
People of lower socioeconomic status are more likely to have worse health, lower life expectancy, and more chronic conditions. The same holds true when researchers look at rates of stress and depression.
Traditionally, researchers studying this phenomenon have looked at data at one point in time, but they have not tracked how health is impacted over a person's lifetime. A research group led by Gregory Miller, Ph.D., a psychology professor at Northwestern University's Institute for Policy Research, wanted to know what happens to the health of those whose socioeconomic status changes over time, known as "socioeconomic mobility."
Their study, published in the Journal of the American Heart Association, looked at adolescents and adults over time, in order to see what effect socioeconomic mobility had on stress levels and health.
They found that when a person transitions out of poverty they tend to experience less stress and depression. However, some illnesses traditionally correlated with poverty remained -- despite their high socioeconomic status.
People who climbed the economic ladder still experienced higher rates of metabolic syndrome, a group of conditions that lead to a higher risk of heart disease including high blood pressure, high cholesterol, high blood sugar and excess fat around the waist.
Miller’s research group first noted these findings in a small group of African American youth in rural Georgia with low socioeconomic status. Their health was followed for several decades, but even the ones who ultimately improved their socioeconomic standing seemed to be haunted by some of the metabolic health disorders that are more likely to be present in the communities in which they grew up.
"We started to ask why,'' Miller said. "And we started to try to see if this was also true outside of the context of small, rural towns in Georgia in studies of African American working poor families ... [we wanted to] use more representative samples that are more economically, racially and ethnically diverse, and ask the same kind of general question about what does mobility look like for health."
The resultant prospective study, which looked at 9,419 people from two nationally representative data sets, answered Miller's question. Even in a diverse sample of study participants that included men and women of all races, the higher risk of metabolic disorders and related heart conditions lingered in people who were upwardly mobile. Those who held high socioeconomic status throughout their life did not see these negative health effects.
Surprisingly, the levels of metabolic syndrome were higher than even individuals with "consistent life course disadvantage": Those who stay at low socioeconomic status throughout their lives.
The results may upend some of the long-standing beliefs that high socioeconomic status means better health.
“We previously believed that higher socioeconomic status is associated with better health outcomes and lower cardiovascular risk," said New York University professor, cardiologist and American Heart Association spokesperson Dr. Nieca Goldberg. "The results suggest upward mobility entails a trade-off, where improving financial conditions forecast higher psychological well-being, but worse cardiometabolic health.”
She also noted another interesting implication of the study: Psychosocial health is not necessarily tied to cardiometabolic health.
While we don't understand exactly why people who ascend to higher economic status are still likely to have these types of health problems, Goldberg said it could be because those people are so focused on pursuing economic betterment that they don't make time for diet and exercise.
The researchers who led the study also suggested that discrimination, social isolation in educational and professional environments, and internal conflicts about class identity could all take a toll on someone's health.
"We sort of assume that because people have the same education and same occupational title that they're all kind of reaping the [same] benefits," said Miller, "but that's probably not true."
For doctors, this means asking about a patient's life history to get a better understanding of their risk of metabolic disease. And for everyday people, the study suggests that -- contrary to the prevailing belief -- wealth may not always equal health. Upward mobility is not uniformly beneficial for health, even if it improves economic standing.
Nancy A. Anoruo, M.D., M.P.H., is an internal medicine resident physician with a focus on public health at the University of Massachusetts and a former health disparities research fellow at the National Institutes of Health. She is a contributor to the ABC News Medical Unit.