Hartford, Connecticut – One of the most disturbing trends in American public health is that women’s life expectancy is shrinking in many parts of the U.S.

Women’s longevity took an unprecedented nosedive during the past decade, researchers recently discovered, with their life expectancy tumbling or stagnating in one of every five counties in the country.

In Connecticut, for example, New London County saw a drop in longevity, while Fairfield and Hartford counties saw significant jumps.

The last time life expectancy fell for a large number of American women was 1918, due to Spanish influenza.

Growing Work, Family Stress

While many scientists believe that smoking and obesity are driving the downward spiral, a growing chorus of experts contends that chronic stress may be a key culprit, too — especially the stress of juggling work and family.

“It’s a hypothesis at this point, but a reasonable and plausible one,” said James S. House, a professor at the University of Michigan’s Institute for Social Research. Women may have gained work opportunities over the last four decades, he said, but society has done relatively little to help them support their increased responsibilities.

“Clearly, obesity and smoking are things that contribute to chronic disease and reduced life span,” said Carolyn Mazure, director of Women’s Health Research at Yale, which funds interdisciplinary research on gender differences in health. “There is really no question in my mind that stress plays a role in that algorithm, especially for women.”

Life expectancy studies show that women’s projected longevity declined or stagnated in 662 counties in the United States — more than 20 percent of the 3,198 counties in the nation — between 1999 and 2009. The largest declines are in parts of the South, Appalachia and the southern portion of the Midwest.

Even in counties where women are living longer, their extra years are often marred by chronic diseases or disabilities, said Chloe Bird, a senior sociologist at the Rand Corp.

The projections for women are in stark contrast to changes in American men’s life expectancy, which had downturns in only 167, or five percent, of the nation’s counties, according to a study by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington in Seattle.

In Connecticut, women’s life expectancy is 82.6 years for girls born in 2009, compared to 81.3 years in the U.S. as a whole. Overall, the life expectancy for Connecticut women increased 1.5 years between 1999 and 2009 — slightly less than the U.S. average of 1.7 years.

But within the state, there are differences. Longevity for women in Fairfield County is the highest in Connecticut — 83.7 years, which is a longer life expectancy than the national average, and more than two years longer than that of Windham County (81 years).

In terms of change over the last decade, Fairfield and Hartford counties saw the largest jumps in female longevity, with increases of 2.2 years since 1999. At the other end of the spectrum, women in New London lost 0.1 year over the last decade, while women in New Haven, Litchfield and Windham saw gains lower than the U.S. average.

Ridged Schedules and No Childcare

At Harvard University, Lisa Berkman, director of the Center for Population and Development Studies, said challenging social conditions in the U.S. have created a “perfect storm” that can damage women’s health.

Not only did women flood into the job market over the past few decades, she notes, but the number of single parents skyrocketed. Despite these major changes, the U.S. has created few policies to help women handle childcare. As a result, there are “extreme stresses even on the relatively advantaged,” Berkman said.

Job stress can be particularly damaging for employees who hold jobs with rigid hours and high demands, such as clerical, administrative or production work, researchers have found.

When Berkman studied women stressed by work and family conflict, she found they had more medical issues than other working women. She looked at women who worked in elder care facilities, comparing those who had rigid and flexible job schedules.

Women with rigid schedules were twice as likely as women with more flexibility to have at least two risk factors for cardiovascular disease, such as high blood pressure, high cholesterol, being overweight or smoking, Berkman found.

Another study, by Harvard Professor Michelle Albert, concluded that women with all sorts of demanding jobs were 38 percent more likely to have strokes, heart attacks or cardiovascular problems, compared to women with less demanding work.

“Chronic stress may promote earlier onset of chronic diseases,” said Elissa Epel, an associate psychiatry professor at the University of California, San Francisco, who helped discover that such stress wears down telomeres, the protective tips of chromosomes, which have been linked with longevity.

“Chronic stress speeds up the aging clock,” Epel stated.

Food, Exercise, Smoking, Family Care

Some studies suggest that women are more likely than men to soothe themselves by eating, the Rand Corporation’s Bird said. They may also be more likely to reduce exercising so they can fulfill their work and family obligations, she said.

Work and family demands also can increase the amount of stress hormones surging through women’s bodies, Bird said. Women do not experience the same decline in stress hormones as men during lunch breaks or after work, since they often use those hours to deal with family issues.

Stress can affect health in two distinct ways. There may be physiological changes, due to excess stress hormones, like cortisol. But it also may cause women to change their behaviors, cutting out such healthy activities as exercise, or indulging in smoking or overeating.

Mazure, of the Yale School of Medicine’s center on Women’s Health Research, was among a cadre of researchers who began studying the impact of stress on women’s health in the 1990s. Even as studies have shown that stress is closely tied to depression, cardiac disease and other chronic illnesses in women, “we know a fraction of what there is to know” about gender differences, she said.

Among the ongoing studies at the Yale center is one examining gender differences in the neurobiological pathways involved in smoking — an attempt to explain why nicotine replacement therapies used for quitting have not been as effective for women as for men.

IHME analyzed the new mortality data by age, sex, and county, from 1989 to 2009. Across U.S. counties, life expectancy in 2009 ranged from 66.1 to 81.6 years for men, and 73.5 to 86.0 years for women. From 1989 to 2009, life expectancy for men improved by 4.6 years on average, but only by 2.7 years for women.

The 2009 longevity numbers also show a growing gap between women living the longest lives and those living the shortest. In Collier, Fla., women live 85.8 years on average. In McDowell, W. Va., they live to be 74.1. That’s an 11.7-year gap. In 1989, the gap was 8.7 years.

US Fares Worse Internationally

International data show that American women are faring worse than their counterparts in other countries. While 50-year-old women in the U.S. had the 11th-longest life expectancy among industrialized nations in 1980, their international ranking plummeted to 21st by 2006. Data from 2010 show American women’s life expectancy at 80.8 years, compared to the world’s highest life expectancy for women in Japan, 85.7 years, and 84.4 years for women in France.

Overall, American women were extending their longevity at a much slower pace than women in other countries, even though the U.S. was spending much more than other nations on medical care.

The National Research Council became so concerned about these international health trends that it convened a 15-member panel to examine seven possible risk factors, including smoking, obesity, social inequality and the U.S. health care system.

Last year, it concluded that smoking played a major role, accounting for 78 percent of the life expectancy gap between American women and those from industrialized countries in 2003. American women began smoking later than men, which experts say may explain why women now have more smoking-related illnesses. Obesity also played an important role, the panel concluded.

Shortly after the report was completed, Berkman, who served on the panel, said she realized the committee had made a glaring omission.

“It hit me like a sledgehammer,” she said. The panel had not evaluated the impact of work stress, let alone work-family stress, on life expectancy. Now, Berkman is leading a new study, funded by the National Institute on Aging, which explores the effects of stress on women’s health and possible interventions.

Berkman doesn’t think it’s a coincidence that American women began suffering from more health problems after they entered the workforce in greater numbers. As American women began working more after World War II, their fertility remained the same, as did the paucity of work-family accommodations.

That’s a contrast to some European countries, where women received more government support to deal with their dual roles or decided to have fewer children. In France, where women have the second-highest life expectancy in the world, childcare options are plentiful, and women with three or more children are eligible for up to 24 weeks of paid maternity leave. In Italy, where female life expectancy also remains high, the fertility rate has dropped in recent decades.

Both Berkman and House acknowledge that smoking and obesity clearly hurt female life expectancy. But they say they may be consequences of women’s stress — not the primary driver of what’s harming women. House’s current research suggests that smoking may explain only about 10 to 25 percent of women’s health decline.

“Women are taking care of lots of other people, and they are not taking care of themselves,” he said.