For more than 25 years, Mary Read was a successful nurse in Lititz, Pennsylvania. But in 2010, at the age of 50, she started having trouble with her memory and thinking, making it difficult for her to complete routine tasks and follow instructions at work. The problems worsened, bringing her career to an abrupt end. In 2011, her doctor conducted a comprehensive evaluation, including a cognitive assessment, and found that she was in the early stages of younger-onset Alzheimer's, which affects hundreds of thousands of people under 65.

A year earlier, Elizabeth Wolf faced another sort of upheaval. The 36-year-old community health program director was forced to abandon her own career, home and community in Vermont when both of her parents were diagnosed with Alzheimer's three months apart. Wolf took the difficult decision to move back into her childhood home in Mount Laurel, New Jersey in order to become their primary caregiver.

These stories are not unusual. Alzheimer's dementia disproportionately affects women in a variety of ways. Compared with men, 2.5 times as many women as men provide 24-hour care for an affected relative. Nearly 19 percent of these wives, sisters and daughters have had to quit work to do so. In addition, women make up nearly two-thirds of the more than 5 million Americans living with Alzheimer's today. According to the Alzheimer's Association 2016 Alzheimer's Disease Facts and Figures, an estimated 3.3 million women aged 65 and older in the United States have the disease. To put that number in perspective, a woman in her sixties is now about twice as likely to develop Alzheimer's as breast cancer within her lifetime.

Researchers are racing to figure out why. Women generally live longer than men, but mounting evidence suggests that longevity alone may not account for the unequal disease burden women face. It remains unclear whether women are truly at an increased risk for Alzheimer's. But studies have revealed that there may be distinct biological and genetic factors shaping how the disease develops and progresses in women. Understanding these differences will be of key importance in devising new, more effective strategies for treating, preventing and diagnosing Alzheimer's.

Consider the example of heart disease. The death rate dropped by nearly half as awareness that it was the leading cause of death in women rose dramatically during a 12-year period beginning in 1997. Now, research uncovering biological differences in heart disease is continuing to help doctors fine-tune diagnosis, prevention and treatment for women. For example, cardiologists are modifying how they identify potential risk factors, adjusting blood thinner dosages, and prescribing low-dose aspirin depending on a person's sex, particularly for older women who have already had a heart attack. Tackling Alzheimer's now requires a similar vision.