The study, conducted by the National Center for Women and Aging at Brandeis University and the National Alliance for Caregivers, found that two-thirds of people who act as caregivers had to pass up such gains as promotions, pay raises, training opportunities and pension benefits.
But caregiving also satisfied a sense of family duty and love.
"People tell of stresses they feel but none of them sound angry because many expected the obligation and see it as a private matter," said Dr. Phyllis Mutschler, executive director of the National Center for Women and Aging. "But people are also saying, 'I can't be effective at work.'"
The study centered on 55 people who spent more than eight hours per week providing unpaid care.
Among the 30 subjects who could provide detailed financial information, the average loss over a lifetime was $659,139 in wages, pension and Social Security benefits, the study found.
The project's participants came from a 1997 study of 1,509 people which found that 1 in 4 families had at least one member who had provided care for an elderly relative or friend in the past year.
The 55 subjects were all over age 45 and had provided either physical or administrative care for a parent, spouses, sibling or friend for an average of eight years.
The respondents reported making frequent work sacrifices, both large and small.
Sixty-nine percent reported arriving late or leaving work earlier than normal. Sixty-seven percent reported taking time off during the day to attend to an elderly dependent.
Sixty-four percent of respondents said they used sick days or vacation time for caregiving duties. Twenty-two percent said they took a leave of absence, and 20 percent reduced their career from full- to part-time. Sixteen percent quit their jobs, and 13 percent retired early to devote more time to an elderly person.
Some said caregiving affected their ability to advance at work.
Twenty-nine percent said they had passed up a promotion or training assignment, while 25 percent said they had refused a transfer or relocation opportunity because of their duties. A smaller percentage said they were not able to acquire new job skills or keep up with important advances in their fields.
Because three-fourths of caretakers are women, the financial burden rests disproportionally on them, Mutschler said.
The impact of lost worker productivity due to elder caregiving on corporate America is estimated at between $11 billion and $29 billion annually, said Sandra Timmermann, a gerontologist for New York-based Metropolitan Life Insurance Co., the study's sponsor.