I've seen this happen in person, to my grandmother. She hitched her identity to the man of the house, even signing checks "Mrs. grandad's name." She was the accountant of their farm along with housewife and cook and chicken tender. He was most of the muscle until he had to relinquish the work to their youngest son, who had moved out and into his own house. She was in relatively good health when grandad died at 76. She suddenly lost her identity, being alone in that farmhouse which she helped build and maintain, it was too full of ghosts to live alone, she moved in with the son. I never saw her smile after that. She died within months.

My great-grandmother was different. her husband died young. she had 50 more years of life after that. She gardened, she sewed, she pickled and canned. She established a strong personal identity and experienced evergreen personal growth. She was a happy woman, cackling all of the time when we'd visit. When she died at 95, it was a surprise, she seemed very alive and healthy shortly beforehand. She died in her sleep, no chronic diseases.

Makes me think that 32% might be traced to psychological/sociological factors.