The findings also indicate that this link between the deceased spouse and surviving spouse is as strong as that between partners who are both living, researchers from the University of Arizona in US said.
For the study, they turned to the multinational, representative Study of Health, Ageing, and Retirement in Europe (SHARE), an ongoing research project with over 80,000 ageing adult participants across 18 European countries and Israel.
Specifically, they examined data from 546 couples in which one partner had died during the study period and data from 2,566 couples in which both partners were still living.
The data also provided evidence for interdependence between partners - a participant's quality of life earlier in the study was associated with his or her partner's quality of life later.
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The results showed interdependence between partners even when one partner died during the study; the association remained even after researchers accounted for other factors that might have played a role, such as participants' health, age, and years married.
Researchers found no observable difference in the strength of the interdependence in couples' quality of life when comparing widowed spouses with spouses whose partners remained alive.
"At some level, this accentuates how important relationships are for our well-being, but the findings cut two ways - if a participant's quality of life was low prior to his or her death, then this could take a negative toll on the partner's later quality of life as well," Bourassa said.
The findings were published in the journal Psychological Science.