London: A broken heart could snuff out life in the wake of bereavement, which weakens our immune system and its ability to ward off infections, says a study.

Scientists have found that emotional upheaval at the loss of a loved one trigger suppression of parts of the immune system, leaving grieving relatives more vulnerable to bacterial infections.

The findings may help to explain anecdotal incidents of widows and widowers who have died days or even hours after their spouse. Former prime minister James Callaghan died of pneumonia aged 92 in 1995, just 10 days after Audrey, his wife of 67 years died.

Now immunologists at the University of Birmingham have found that increased stress levels and depression brought on by grief can interfere with the function of a type of white blood cell known as neutrophils, which are responsible for fighting bacterial infections like pneumonia, the Telegraph reported.

The impact becomes more pronounced in older adults as they lose the ability to produce a hormone that can stave of this dampening affect, meaning even previously healthy elderly people can fall victim to disease following a bereavement.

Janet Lord, professor at Birmingham, who led the research, said: "There are a lot of anecdotes about couples who were married for 40 years - when one of them passes away and then the other dies a few days later. It seems there is a biological basis for this."

"Rather than dying of a broken heart, however, they are dying of a broken immune system. They usually get infections," added Lord.

The researchers studied the immune systems and hormone levels of 48 healthy adults aged 65 and over. Half of the group had suffered a major bereavement in the past 12 months.