Illness of a spouse can harm the health of the partner, according to a new study released in The New England Journal of Medicine. It confirmed the so-called widower effect among 500,000 elderly couples aged 65 and older, according to co-author Paul Allison, professor of sociology at the University of Pennsylvania.

"When a wife dies, the risk of the death of the husband in the next 30 days is elevated by about 35 percent," he says. "If the husband dies, the wife's risk of death in the next 30 days is elevated by an even larger amount, by about 44 percent."

The study finds that when a spouse is hospitalized, the partner's risk of death increases significantly and remains elevated for up to two years. Allison says certain diseases are more harmful to partners than others.

"Diseases which we typically associated as being among the worst in terms of mortality, such as lung cancer, pancreatic cancer or colon cancer, had relatively little impact on the chance that the spouse would die," he says.

Those whose spouses had dementia and other psychiatric conditions were under the most stress. If a wife was hospitalized for dementia, her husband's risk of death was 22 percent higher. Similar effects were seen in women. Allison says that and a lack of social support had a psychological effect on partners.

"Some gerontologists have certainly suggested that this research emphasizes the need for both social and medical support for the spouse of a partner who is hospitalized," he says, adding that it "makes good sense."

Allison says illness or death in an elderly couple can also create a cascading, debilitating effect on other members of the family and close friends.