New York, June 2 (IANS): Unsupportive parenting styles may have several negative health implications for children including premature ageing and higher disease risk later in life, says a study.

The research found that the telomeres -- protective caps on the ends of the strands of DNA -- of participants who considered their mothers' parenting style as "cold" were on average 25 per cent smaller compared to those who reported having a mother whose parenting style they considered "warm".

The research has found that early-life stress is associated with shorter telomeres, a measurable biomarker of accelerated cellular ageing and increased disease risk later in life.

"Telomeres have been called a genetic clock, but we now know that as early life stress increases, telomeres shorten and the risk of a host of diseases increases, as well as premature death," said lead author of the study Raymond Knutsen, Associate Professor at Loma Linda University School of Public Health in the US.

"We know that each time a cell divides, the telomeres shorten, which shortens its lifespan," Knutsen added.

Interestingly, mutations in genes maintaining telomeres cause a group of rare diseases resembling premature ageing.

"However, we know that some cells in the body produce an enzyme called telomerase, which can rebuild these telomeres," Knutsen said.

The study, published in the journal Biological Psychology, used data from 200 participants.

"The way someone is raised seems to tell a story that is intertwined with their genetics," Knutsen said.