News

doi:10.1038/nindia.2015.30 Published online 9 March 2015

Stress cuts down life-expectancy of Madhya Pradesh tribes

Vijay Shankar Balakrishnan

Members of a particular tribal community in the central Indian state of Madhya Pradesh are so socio-politically stressed out that their life-expectancy might be going down as a result, a new study reveals1.

Anthropologists have found high levels of stress markers in the saliva and buccal cells of the Sahariyas, adivasis who live in villages near the Kuno wildlife sanctuary in the Sheopur district of Madhya Pradesh.

A young Sahariya giving his buccal cells for the stress survey
© Jeffrey Snodgrass
Lead researcher Jeoffrey Snodgrass, an anthropologist from the Colorado State University, Fort Collins, USA, says he got interested in the lives of the Sahariyas in 2008 after learning about the stress of displacement of the tribes living in and around the sanctuary.

About 8000 tribes from 24 villages near the sanctuary were relocated to newly constructed villages as part of the Asiatic Lion Reintroduction Project. The displacement was done with an intent to prevent man-lion encounters as lions were introduced into the sanctuary from Gir in Gujarat.

The researchers collected cheek swabs from 46 Sahariyas and microscopically assessed the lengths of telomeres, the ends of the chromosomes. Telomeres naturally shorten with age, whereas high level of physical and mental stress pre-maturely shortens them, making even younger people susceptible to old-age disease. The stress also cuts short such people’s normal life expectancy. The researchers found all of these in the Sahariyas.

The researchers also found abnormal levels of two other stress markers – the hormone cortisol and salivary enzyme α-amylase – in the Sahariyas.

Despite being compensated with land and money, the Sahariyas’ confrontations with bandits and semi-nomadic herders from Rajasthan compound the stress caused by their poverty and displacement, Snodgrass says. “The Sahariyas were continuously harassed by bandits, which eventually led to the villagers even killing a well-known bandit”, says Snodgrass.

This is the first time such a study has been done in a non-western setting. And Snodgrass aims at conducting more such studies in the future. He says, “With enough studies, we could start to better plot the relationship between stress and telomere length/maintenance across a fuller range of humanity."

Suresh Rattan, a biogerontologist at Aarhus University, Denmark, says, “Such studies do draw attention to the fact that our bodies get affected by psychosocial stress and [that] lots of things may change." But he warns that it would be too simplistic to make conclusions about complex biological processes such as stress and ageing with just a few markers or small sample size.


References

1. Zahran, S. et al. Stress and telomere shortening among central Indian conservation refugees. P. Natl. Acad. Sci. USA (2015) doi: 10.1073/pnas.1411902112