PHILADELPHIA--A new study by researchers at the University of Pennsylvania and Harvard Medical School shows that for people aged 65 and older hospitalization of a spouse can harm the well being of the surviving partner and significantly contribute to that partner's death.

The study appears in the Feb. 16 New England Journal of Medicine.

Paul Allison, professor and chair of Penn's Sociology Department, and Nicholas Christakis, professor in the Department of Healthcare Policy at Harvard Medical School, examined the effect of illness in one spouse on the risk of illness in a partner.  This is commonly called the caregiver burden. Concurrently, they looked at the effect of the death of one spouse on the mortality of the other.  This is known as the widower effect.  By considering these effects together for the first time, the authors were able to assess the implications of specific illnesses or diseases for a partner's risk of death.  The study found that certain illnesses in a spouse are more harmful to partners than others.

"What surprised us was that diseases that are highly lethal, like lung cancer or pancreatic cancer, had very little impact on the partner's mortality risk," Allison said.  "On the other hand, dementia and other psychiatric diseases showed substantial increases -- 19 to 32 percent -- in the risk of death for the partner, for both husbands and wives."  While these diseases have low fatality rates for the patient, at least in the short run, they impose a great burden on the partner."

Researchers found that the period of greatest risk is within 30 days of a spouse's hospitalization or death.  During this time frame, hospitalization of a spouse can confer to a partner almost as much risk of dying as the actual death of a spouse.

The study also found that specific illnesses impacted the spouse differently.  For example, among men with hospitalized wives, if the

wife were hospitalized for colon cancer, there was almost no effect on her husband's mortality. But, if a wife were hospitalized with heart disease, her husband's risk of death was 12 percent higher than it would be if the wife were not sick at all.  If a wife were  hospitalized with dementia, her husband's risk was 22 percent higher.  Similar effects were seen in women whose

husbands were hospitalized.

Further analyses also confirmed that the death of a spouse within the past 30 days was harmful.  The death of a wife in the previous 30 days increased her husband's risk of death 53 percent, and the death of a husband increased his wife's risk of death 61 percent.

For women, the effect of a husband's hospitalization increased with age and the level of poverty.  For men, the effect of a wife 's hospitalization increased only with age.

This is the largest study of its kind.  Beginning in 1993 and continuing for nine years, the authors studied 518,240 couples- more than 1 million people- between the ages of 65 and 98 who were enrolled in Medicare.  During the nine years, 383,480 husbands (74 percent) and 347,269 wives (67 percent) were hospitalized at least once, and 252,557 husbands (49 percent) and 156,004 wives (30 percent) died.  The mean age of men in the study was 75 years, and the mean age of women was 72 years.

Although illness and death both create stress and have a negative effect on social support for a partner, these results operate during various time frames.  This study found that the stress effect may last for a few weeks or months, and the support effect may last for several years.  Eventually, the healthy partner adapts to the stress effect, so that the health risks of being a caregiver decline; however, the lack of social support that is associated with the illness or death of a partner becomes a problem, and health risks in the partner increase again.

The work was supported by the National Institute on Aging, a division of the National Institutes of Health.