'The study does not have to do with poverty, per se,' said lead author Sheldon Cohen, Ph.D., a psychiatry professor at Carnegie Mellon University. He said the purpose of the study was to understand how stressors can influence health: 'We need to really show that this relationship exists.'
The study included 193 adults with yearly incomes ranging from $2,500 to $162,500, but leaning toward the lower end of the scale, with an average income of $17,500. Average education was 13.76 years.
To measure stress hormone levels, participants gave two 24-hour urine samples for determining epinephrine and norepinephrine levels, and a series of saliva samples for cortisol levels on each of three days. Lower socioeconomic was associated with higher levels of all three stress hormones.
Low socioeconomic status was also associated with a greater incidence of smoking, of not eating breakfast and with having a less diverse social network. These behaviors and social variables appear to strengthen the link between socioeconomic status and hormone levels, with about 63 percent of the association explained by smoking alone.
Eating breakfast regularly was seen as a bellwether for overall healthy behavior, and having a strong social support network is known to reduce stress levels, Cohen said, adding that every upward increment of socioeconomic status increases the likelihood of better overall health.
Yet there still exists an idea that stress goes with greater socioeconomic status rather than the reverse, said Nancy Adler, Ph.D., a professor of medical psychology at the University of California at San Francisco. She said the association between stress, socioeconomic status and smoking is important: 'How do we help people who are poor and under stress not cope by smoking?'
Adler suggested the possibility that 'kids in poorer systems get much less training in critical thinking and how to anticipate crises. There are ways to reduce the chaos of the stress,' she said. 'Things like that are trainable.'