Women make up two-thirds of the 5.1 million people currently suffering from Alzheimer’s disease in the United States. But that figure doesn’t fully capture the disease’s disproportionate impact on women, according a new analysis of the economic costs of the disease. Thanks to the fact that women are more likely to develop the disease themselves and to take care of a loved one who has been diagnosed with it, the researchers estimate that, per capita, women bear six times more of the cost of care for Alzheimer’s than men do over the course of their lifetimes.

A woman’s overall risk of developing Alzheimer’s is almost twice that of a man’s. Until recently, that disparity was attributed largely to the fact that women tend to live longer and are therefore overrepresented among the elderly, who are mostly likely to be struck by the disease. But researchers have discovered that women are at higher risk even after taking longevity into account. Research by Dr. Richard Lipton, who heads the Einstein Aging Study at Albert Einstein College of Medicine in New York, has found that that women in their 70s are twice as likely as men in the same age to develop Alzheimer’s or other forms of dementia. After age 80, men and women are at similar risk for the rest of their lives.

What if men bore six times the economic cost of Alzheimer’s in the U.S? How much more quickly would public pressure build for reforms to lighten the load?

The underlying reasons for this gender disparity could include the biological, the cultural, or both—from genetic sex differences to the role of estrogen to women’s higher rates of depression. But such research is still in its infancy. According to a group of female Alzheimer’s researchers, that’s in part because men have long dominated the field. Women’s health advocates, too, have identified Alzheimer’s as one of several key diseases where gender-specific research has been neglected and is urgently needed.

Meanwhile, between 60 and 70 percent of informal caregivers of people with Alzheimer's are women—usually the patient’s wife, daughter, daughter-in-law, or other female relative. To put it mildly, it’s a particularly time-consuming and emotionally draining role. People with Alzheimer’s become dependent on assistance for daily tasks—like bathing and dressing—and, often, they need care for quite a long time, since patients live with the disease for an average of five years. Last year, each of the 15.7 million unpaid caregivers of people with dementias spent, on average, more than 20 hours per week taking care of their loved ones. A survey conducted by the Shriver Report and the Alzheimer’s Association found that half of women caring for someone with Alzheimer's are providing more than 40 hours of care a week. A third are caring for them 24/7.

It’s primarily this informal, unpaid care that results in such an enormous gender gap in the analysis published in last month’s Women’s Health Issues. The researchers calculated the cost burden for women and men based on the probability of developing the disease, the disease's duration, and the cost of formal and informal care that patients need. Included in the cost analysis is the clinical care paid by Medicare and long-term care paid by Medicaid; assisted living care and home health care paid for out-of-pocket by patients and their families; and uncompensated informal care provided by loved ones.

While female Alzheimer's patients end up costing Medicaid and Medicare more than their male counterparts—mostly because women are more likely to be poor enough in old age to qualify for Medicaid—it’s in the costs that are shouldered by patients and their families where the gender disparity is really significant. In large part, it’s just an inevitable result of timing: “When a man develops the disease, it’s likely he has a surviving wife. But when a woman gets the disease, she’s most often widowed,” says the study’s co-author Zhou Yang, an assistant professor in Emory's Rollins School of Public Health. What this means over the course of a lifetime is that women often find themselves first becoming a caregiver to their spouse or other family member with Alzheimer’s—forced to choose between draining their savings to pay someone else for in-home care, providing unpaid informal care themselves, or some combination of the two—and then developing the disease themselves years later without a partner to lean on. As a consequence, women lose, on average, $6,888 to assisted living costs (versus $1,084 for men), $9,212 on home health care costs (versus $1,462 for men), and—estimating that a year of such care has a replacement cost of $27,789—$54,956 for unpaid informal care (versus $8,659 for men).

At the aggregate level, among the entire 76 million people in the Baby Boomer generation, women will end up bearing 20 times more of the cost of informal Alzheimer’s caregiving than men will.

Amazingly, that’s a low-end estimate. One limitation of the study, Yang explains to me, is that, to simplify the calculation, they assumed that the patient’s spouse is the main caregiver. And given that the majority of spouses of Alzheimer’s patients would be retirees, the analysis doesn’t reflect any lost income from providing informal care. But in the real world, since many Alzheimer’s patients no longer have a spouse or their spouse is too sick or frail themselves to be much help, it’s actually much more common for children, grandchildren, or other relatives and friends to provide the most care. Only about a third of Alzheimer’s caregivers are over age 65. The rest are juggling caregiving during their working years, and nearly one-fourth are in the “sandwich generation”—caring for both for an Alzheimer’s patient and a child or grandchild of their own.

It’s not demographic trends dictating that these younger caregivers are mostly women—but they are. “The reality is that a lot of caregivers are middle-aged women, and these women will suffer lost income, so my estimate of the costs of informal care tends to be conservative,” Yang says. “The reality is worse than my analysis.”

Some overdue reforms to Medicare and Medicaid could help alleviate this economic burden. Medicare’s fee-for-service payment model just doesn’t adequately address the needs of people with chronic conditions like Alzheimer’s. “Medicare only pays when you’re in the hospital or the physician’s room. So usually when Medicare kicks in, it means patients are very sick,” Yang explains. “If, as a society, we could figure out more creative models, we could probably take care of Alzheimer’s and dementia patients better within their own homes in their own communities—and with lower costs.” As it is, what these patients need most is ongoing daily assistance and monitoring—the kind of long-term care that Medicare doesn’t cover at all.

Meanwhile, Medicaid does cover long-term care—but usually only in a nursing home. Though some states are encouraging home-based long-term care through Medicaid waiver programs, it’s not a widespread alternative. Plus, you have to be very, very poor to qualify for Medicaid. These gaps leave Alzheimer’s “patients and their families, in particular, female patients and caregivers, with difficult choices: either to take care of their loved ones at home at their own cost or to spend down the patient’s savings and assets and place them in a [long-term care] facility that is reimbursed by Medicaid,” the researchers write.

Of course, the best solution—for everyone—would be to discover a way to cure or prevent Alzheimer’s. That, the researchers conclude, “could increase the well-being of the entire population and significantly improve quality of life for women, in particular, middle-age and elderly women.” But we certainly don’t seem to working very hard at that. Alzheimer’s is the only disease among the top 10 causes of death in the U.S. for which we don’t yet have a reliable way to prevent, cure, or slow its progression. Yet federal funding for research on the disease currently stands at less than $600 million annually. To put that into perspective: Cancer affects three times as many people as Alzheimer’s does but gets 10 times as much funding. Scientists say that they’ll need $2 billion a year to make any real progress and consistently warn that Alzheimer’s is a “sleeping giant” that is not being taken seriously enough.

How seriously should it be? As the Boomers age, the number of Alzheimer’s cases in the U.S. is expected to more than triple to nearly 14 million by 2050. Already the epidemic is worse than we might have realized: Last year, an analysis concluded that the disease may actually be the third leading cause of death in the U.S.—after heart disease and cancer—not the sixth, as the official figures indicate. And some research suggests the ballooning numbers reflect not simply an increasingly older population but an actual increase in incidence rates: A study released in August concluded that rates of death from dementia and other neurological diseases have increased over the last few decades worldwide—and have especially sky-rocketed in the U.S., rising two-fold for elderly men and more than five-fold for elderly women.

It seems clear enough that we’ve been slow to recognize and address the growing Alzheimer’s epidemic, and women will disproportionately shoulder the burden.

Feminists have long recognized women’s unpaid domestic labor as an unacknowledged subsidy to capitalism. Treated as simply an extension of women’s “natural” nurturing role, this work—cooking, cleaning, caring for the young, old, and sick—is the uncompensated and undervalued “work that makes all other work possible.” And it’s not just the economic system that benefits from it. Earlier this year, Pacific Standard’s Francie Diep covered a report showing how, worldwide, women’s unpaid caregiving serves as an enormous "invisible subsidy to health systems and societies.”

Framing women’s unpaid caregiving as a subsidy helps expose a couple of realities. Most obviously, it makes this hidden work visible—and shows how dependent on it we all really are. And more importantly, in my opinion, it suggests that, without this unrecognized subsidy, society and its systems—the economy, the health-care system—might be forced to work better. After all, subsidies skew the market, as any economist—particularly one who indulges in the fantasy that we have a free one—will tell you. By artificially keeping costs low, they can end up propping up a system that needs to evolve or die.

Put another way: Perhaps we’ve been slow to recognize and address the growing Alzheimer’s epidemic because women disproportionately shoulder the burden.

What if men bore six times the economic cost of Alzheimer’s in the U.S? What if it was mostly men who devoted a total of $17.9 billion of unpaid care to a loved one with the disease last year? What if it was mostly men—many of them in the prime of their careers and raising kids to boot—who were forced to take time off from work, take a less demanding part-time job, or quit altogether to provide this care? What if it was mostly men who saw their own emotional and physical health suffer for it—to the tune of $9.7 billion in increased health-care costs themselves?

How much more quickly would public pressure build for reforms to lighten the load? For innovative new models to provide coordinated, long-term care for Alzheimer’s patients under Medicare and Medicaid; for an expanded workforce of well-compensated and well-trained professional caregivers; for access to affordable and not soul-crushing assisted living facilities and nursing homes for all; for a federal paid family and medical leave law for those who want to take care of their loved ones themselves but can’t afford to sacrifice their incomes to do so.

How long would it take, in other words, for this care to be transformed from a private burden to a public one? How long before more and more of the estimated economic value of this unpaid labor—$217 billion annually—was shifted onto insurance companies and government entitlement programs and employers?

If it were—if the market lost this subsidy—the annual economic cost of Alzheimer’s would nearly double. How seriously would we take it then?

The Gender Gap explores the persisting gender inequalities of the modern age and society's unwillingness to grapple with them.