- Belonging to the lower rung of the socio-economic status, puts a person at risk of constant stress.
- The constant stress causes the immune cells to attack the body and cause unwanted inflammation.
The longer life span of the rich cannot be attributed to just a healthy lifestyle like balanced diet, exercise or refraining from smoking and drinking.
It could also be the impact of being free of stress.
‘Improvements in social status or social support and reducing social hierarchies, can have a positive effect on health and well-being.’
Among those in the lower socio-economic group, the constant stress of being poor makes them ill.
It alters the immune system causing it to go into overdrive and immune cells starts attacking the body by causing inflammation.
Effects of social status on genes
Socioeconomic status is one of the fundamental cause of health inequalities.
In the United States, differences between the highest versus lowest socioeconomic groups affect adult life span by more than a decade.
Social status manipulates the immune system by altering gene activity.
Inflammation occurs in the body when the body's immune system tries to fight off infection, but sometimes this response is not switched off.
Assistant professor of evolutionary anthropology and biology Jenny Tung at Duke University said: 'Social status is one of the strongest predictors of human disease risk and mortality, and it also influences Darwinian fitness in social mammals more generally.
Testing in Rhesus Macaques-
Researchers have shown how social status alters the immune function by conducting tests in female rhesus macaques.
The researchers studied gene activity through social status manipulation. They introduced 45 unrelated female monkeys that had never met each other into new social groups, one by one.
They were ranked on the basis of their bullying, cowering and pecking behaviors.
Females who were introduced earlier tend to rank high and those that those who were introduced later.
Immune cells of the monkeys were then taken and the activity of roughly 9,000 genes measured.
The researchers found that more than 1,600 genes were expressed differently in lower-ranking females than in higher-ranking females, especially within a type of white blood cell called natural killer cells.
These natural killer cells are the first line of defense against infection.
When an infection strikes these low-ranking monkeys, the immune cells go into an overdrive and causes unwanted inflammation.
But improvements in social status or social support can turn things back around.
The study published in the journal Science
states that as macaques are close evolutionary relatives of humans, these results likely point to mechanisms that underlie social status effects in humans as well.
Those macaques, whose status improved, bonded well through grooming and they suffered less stress.
Prof Tung concluded "Together, our findings show that social subordination alone is sufficient to alter immune function even in the absence of variation in resource access, health care, or health risk behaviours."
Similar responses could help explain why poor and working class people have higher rates of inflammatory disorders such as heart disease and diabetes.