85% of people who live to 100 are women. What's their secret?

If you make it to the triple digits, it’s likely that you’ll be surrounded almost entirely by women. That’s because about 85% of people 100 years or older are women, and only 15% are men. Once you get into supercentenarian territory (age 110 or older), that number increases to 90% women.

“While men are usually stronger, women live longer,” Dr. Naushira Pandya, professor and chair of the department of geriatric medicine at Nova Southeastern College of Osteopathic Medicine, tells Yahoo Life. “The difference can potentially be explained by biological traits, as well as social and cultural factors.”

Despite several reasons that reduce women’s overall longevity, like maternal mortality rates and lower socioeconomic status, women manage to live longer across the globe. In the U.S. specifically, women live about six years longer than men. It’s a “puzzling paradox,” says Pandya.

Still, experts say there are many reasons why women tend to live longer than men.

Biological factors

One factor may be female hormones. Estrogen has been shown to have many protective health benefits, from its positive effects on vascular health to boosting antioxidant and longevity-related genes. It has also been linked to anti-inflammatory effects, particularly during times of raised estrogen production, such as pregnancy. And a 2020 cohort study found that postmenopausal estrogen therapy was associated with longer lifespans in older women.

“Estrogens in women reduce oxidative stress at a tissue level, as well as increase the more protective high-density lipoproteins (HDLs) and reduce low-density lipoproteins (LDLs),” says Pandya. “Another contributing factor that may explain a longer lifespan in women is slower aging of the immune system.”

Chromosomes may also come into play. New research published in Science Advances found that the second X chromosome in female mice might offer protective benefits in the brain as they age.

The grandmother hypothesis

Beyond hormonal factors, evolution may also contribute to women’s longevity. The “grandmother hypothesis,” while up for debate, suggests that women may have evolved to have long post-reproductive lives to help raise their grandchildren, increasing their chances of survival and allowing their daughters to have more children.

“Women nurture their children, husbands and elderly parents as if a task they are required to bear,” Moti Gamburd, CEO at CARE Homecare, tells Yahoo Life. To do so, they instinctively construct their lives to prepare for a caretaking role by making sure they themselves are healthy enough to do so, says Gamburd. “They visit the doctor, take medication as instructed and follow habits that will keep them healthy."

Lifestyle factors

This brings us to lifestyle factors, which appear to also play an important role in longevity. For one, men are more likely to avoid going to the doctor than women — so much so that a 2019 survey out of Cleveland Clinic was titled, "Men Will Do Almost Anything to Avoid Going to the Doctor."

Women also tend to be more health-conscious and less likely to participate in risky behavior than men.

“Men have higher rates of smoking, drinking, risky behaviors and health care avoidance,” says Dr. Evan Ciarloni, an internist with expertise in geriatric medicine at Ochsner Rush Health and medical adviser at KINNECT.

Men are also more than twice as likely to die in a car crash in the U.S. and four times as likely to be the victim of a homicide, Ciarloni notes. The suicide rate in males is about four times higher than in females.

Community connections and outlook

Finally, social connections have significant effects on physical health, well-being and longevity in both men and women. In fact, they are critical to survival. A lack of social connection has been shown to be as detrimental to one’s health as smoking up to 15 cigarettes a day.

Since women tend more to seek out and foster friendships and social connections, this may add to the longevity gap. They are also more likely to reach out to a friend or family member when experiencing stress.

“My own clinical experience of over 40 years has shown me that people in their 90s and even centenarians have a greater support system, more social connections, pursue meaningful activities, feel valued and have a sense of humor,” says Pandya. Furthermore, “Older adults who are more committed to their faith enjoy greater mental and physical health.”

And a positive and engaged outlook on life, along with embracing one’s own aging, may help people “outswim their gene pool,” Marilyn Gugliucci, professor and the director for geriatric education at the University of New England, tells Yahoo Life.

In her work in the field of aging, Gugliucci says “purpose” and “resilience” are pivotal. “Of course, eating well and exercise [and] activity contribute to health, but the attitude a person has about aging and how they manifest that in their daily lives, relationships and community are part of the ingredients for a life well lived.”

Habits that help you live longer

No matter what your age or gender, there are several habits that can help you to be the healthiest version of yourself and contribute to greater longevity. These include regular exercise, eating a healthy, well-balanced diet, getting enough sleep, avoiding smoking and reducing alcohol consumption. Other habits include seeking out and maintaining healthy relationships, having a positive outlook and a feeling of purpose and hobbies that bring you joy.

“It’s possible to live a long, healthy life by focusing on your individual risk factors for chronic disease and coming up with a holistic plan,” says Ciarloni. That includes “diet, exercise, sleep, relationships [and] spirituality.”