In the worst cases, people really can die from grief. When a person suffers a great loss, their mix of stress hormones changes. White blood cell count can drop, leaving them vulnerable to infection. In new research published Tuesday, scientists demonstrated that the immune systems of older people are more severely hampered than those of young grieving people because of the way their stress hormones react.

"During the difficult weeks and months after loss we can suffer from reduced neutrophil function," said co-author Dr. Anna Phillips, of the University of Birmingham, in the UK, in a statement. "Neutrophils are the most abundant type of white blood cell and as such are essential at combating infections and illness, so we become vulnerable when this happens." Her paper appears in the journal Immunity & Ageing.

Phillips and her colleagues examined the health of 47 people of different ages who were grieving the death of someone close to them within the last two months. Comparing a younger group and an older group, the scientists discovered differences in how much of two types of stress hormones they had. Younger people had a balanced mix of cortisol and dehydroepiandrosterone sulphate, or DHEAS. But the older group had a higher proportion of cortisol.

Cortisol is a good thing. Janet Lord, another co-author, said it helps to keep stress and inflammation in check. But it's also "known to suppress elements of the immune system during times of high stress," she said, "so having an unbalanced ratio of cortisol and DHEAS is going to affect how able we are to ward off illness and infection when grieving."

A solution to the problem isn't as easy as reducing cortisol levels because, as Lord says, cortisol is "incredibly useful." Phillips says the study primarily helps to illuminate this relatively mysterious area of health science. "The effects of loss are poorly understood on the whole — we know that it affects the immune system amongst other things — but we don't fully understand the role played by our stress hormones," she said. "We hope that this is a step towards that understanding, and being able to provide the best possible support."

Source: Phillips A, Lord J, et al. Bereavement reduces neutrophil oxidative burst only in older adults: role of the HPA axis and immunesenescence. Immunity & Ageing. 2014.