People living in poorer areas are less healthy on average than those living in wealthy areas. This discrepancy covers both physical and psychological illnesses, and has been observed in many area studies worldwide.
The reason for the difference is a trickier question. Does the environment have an impact on a person’s health and lifestyle choices? Or do healthy people tend to congregate in “good” neighbourhoods, while the less healthy gravitate towards poorer areas?
“Area studies have traditionally interpreted the data to mean that the region itself has a health impact," says Markus Jokela, associate professor in psychology. “However, researchers have always acknowledged that the correlation may also have to do with the selection of inhabitants.”
Jokela decided to clarify the issue by using the Australian HILDA research material, which contains data from the lives of 20,012 people, checked annually from 2001 to 2010.
Health status predicts the destination of a move
During the decade of research, some of the people in the study moved away from their original place of residence to a wealthier or poorer area.
“When the people moved, their health status did not change. They were just as healthy or sick, regardless of how prosperous their home area," Jokela says. At the same time, the other explanation gained evidence: “People in better health were more likely to move to a wealthy area."
The results of Jokela's research were published in the American Journal of Epidemiology in autumn 2014, and now, close to six months later, the journal has listed the study among the ten best articles of 2014.
What keeps a child healthy?
Jokela repeated the study later, using British material, and obtained similar results.
However, Jokela points out that these two studies are not enough to fully disprove the hypothesis that place of residence might have health impacts. The environment in which a child grows up, for example, may be significant.
“My research focused on adults who moved to a different area, and for that group, the results are clear. They throw into question the assumption, common in research literature, that the place of residence has an impact on the health of adults.”
The significance of the area with respect to a child is a more difficult chicken-or-egg question. What part of a child’s health is hereditary, and what is a result of the family and environment?
“Science will find a way to figure it out; we just have to take one step at a time. We can use statistical methods to separate phenomena that have become confused,” states Jokela.
“But such difficult questions will require extensive research."