SUNDAY, Feb. 10 (HealthDay News) -- It's called the "widow" or "widower" effect, and doctors have long been familiar with this curious but very real phenomenon: When a husband or wife dies, there's a greater likelihood that the surviving spouse will pass soon afterward.

Now, researchers are gaining a better understanding of the forces at work, realizing problems often start with the hospitalization of a spouse.

New findings suggest that having a husband or wife who needs to be admitted to a hospital with a serious illness poses health risks for the partner. The culprit: The stress and upheaval the partner experiences while enduring the hospitalization of an ailing husband or wife.

"It's not like your spouse's sickness somehow magically makes you worse," said Dr. Nicholas A. Christakis, a professor of medical sociology at Harvard Medical School's Department of Health Care Policy. "We believe it works by imposing some kind of burden."

To unravel the connection, Christakis and co-researcher Paul D. Allison, a University of Pennsylvania statistician, examined records of more than a half million couples who were in enrolled in Medicare from 1993 through 2001. Their findings, published in the New England Journal of Medicine, demonstrate the ripple effect of a spouse's hospitalization -- across various illnesses -- on the partner's health.

"What this work shows is that illness in one person -- in a spouse -- can affect the health, the mortality, of another person," Christakis explained. "And this, in turn, means taking better care of someone who's sick not only benefits the sick person, but also benefits other people, such as their spouse."

In the United States, at least 44 million adults, including spouses, provide care for a loved one, the National Alliance for Caregiving estimates. Yet, few of these individuals are adequately prepared to cope with the rigors of caring for another person or the toll it can take on their health, according to the Family Caregiver Alliance.

Overall, Christakis' study found that a spouse's hospitalization boosted the risk of a man's death by 22 percent compared with the death of a spouse. A husband's hospitalization increased a woman's death risk by 16 percent.

Some diseases posed more of a burden than others. For example, a woman's hospitalization for stroke, congestive heart failure or hip fracture raised her husband's death risk by 6 percent, 12 percent and 15 percent, respectively. Similarly, a man's hospitalization for colon cancer did not significantly influence his wife's death risk, but other diseases did have a major impact.

A spouse's hospitalization for dementia proved most stressful, raising risk of death 22 percent for men and 28 percent for women, Christakis said. "In fact," he added, "we show that having a demented spouse is as bad for you as having a dead spouse."

Some diseases are deadly, but don't pose as much of a burden on the caregiver, be it physical, psychological, financial or some combination of these, he explained.

The study also identified certain time frames during which caregivers are particularly vulnerable, including immediately after a hospitalization and again three to six months into the illness.

Suzanne Mintz, president and co-founder of the National Family Caregivers Association, said the study offers additional proof that the stress of caring for a family member can have negative health consequences.

"The findings should frighten family caregivers," she said, "but more importantly, hopefully, help them give priority status to their own health needs."

Spousal family caregivers' risk of depression is six times greater than that of non-caregivers, Mintz noted. And, they are less likely to reach out for help, she said. To protect their health, Mintz urges family caregivers to spread the work load.

"Caregiving is much more than a one-person job, especially when both the family caregiver and the care recipient are elderly," she said. "Often, spousal caregivers do not want to ask for or take help from their grown children, but that really is the first place we should all turn."

More information

To learn more, visit the National Family Caregivers Association.