Women’s life expectancy lags behind men, matching a national trend, according to county-by-county estimates of life expectancy released today by the Institute for Health Metrics and Evaluation at the University of Washington.

The study thoroughly analyzed county-by-county data from 1989 to 2009. In that time duration, life expectancy for men improved by an average of 4.6 years. However for women, it improved by only 2.7 years.

The report shows the life expectancy of men and women in Marin increasing steadily between 1989 and 2009. During that period, life expectancy rates for Marin men increased from 74.6 years to 81.6 years while life expectancy rates for Marin women grew from 79.7 years to 85.1 years.

"It's tragic that in a country as wealthy as the United States and with all the medical expertise we have that so many girls will live shorter lives than their mothers," Dr. Ali Mokdad, the head of IHME's research team, said in a written statement.

The study also showed a wide gap between women living the longest lives and those living the shortest. For example, in Collier, Florida, women live 85.8 years on average - but in McDowell, West Virginia, they live an average of 74.1 years. That's around 12-year difference.

"The people in Marin decided to live healthier, and they are getting their reward for their lifestyle," Mokdad said. "That's something we'd like to see everywhere else."

Mokdad said “women are losing ground to men because they are more likely to be obese, have high blood pressure and high cholesterol, also, women began smoking in large numbers later than men, so more women are paying the price now.”

"Lung cancer among women is leveling; it's not decreasing in this country," Mokdad said. "Whereas if you look at lung cancer mortality for men, it's going down."

"Women aren't as encouraged by their doctors to get medication to ward off heart disease," Dr. Gina Lundberg, national spokeswoman for the American Heart Association, told USA Today. "And many doctors don't treat their symptoms as aggressively as they do in men. They'll say you have an upset stomach and send you home."

"The main driving forces are the risk factors," Mokdad said, "the preventable causes of death."

Changes in health care treatments are another possible reason behind the gap. "What makes the difference is getting the right medication at the right dose," Mokdad said. "We screen people for diseases but don't always follow through to manage the diseases."