Apple announced three new health studies Tuesday that will address issues of hearing, heart health, and women's health as it relates to menstrual cycles and reproduction.

The studies are part of a continued push by the company to make waves in the health and medical realm. In a January interview, Apple CEO Tim Cook said he expected the company's health-related work to become its lasting legacy and "greatest contribution to mankind."

"Our business has always been about enriching people's lives," he explained.

Apple has unveiled a variety of health-related apps and features recently. In 2016, for instance, the industry giant unveiled CareKit , a software framework for developing healthcare apps. In November 2017, the company started the Apple Heart study , which looked at whether the pulse sensor on older Apple Watches (Series 1, 2, and 3) could help detect irregular heart rhythms, such as atrial fibrillation . With the Apple Watch Series 4 , Apple unveiled a full electrocardiograph feature to help monitor heart activity.

For the new studies, Apple is teaming up with high-profile research partners to correlate gadget-collected health data with a variety of health outcomes.

Everyday sounds and motion

For the hearing study, Apple is working with researchers at the University of Michigan to help understand how everyday sounds and noise relate to hearing loss. Researchers will survey Apple users' sound exposures throughout their days via Apple devices.

"This unique dataset will allow us to create something the United States has never had—national-level estimates of exposures to music and environmental sound," University of Michigan researcher Rick Neitzel said in a statement. Neitzel, an associate professor of environmental health sciences and global public health, will lead the hearing study. "Collectively, this information will help give us a clearer picture of hearing health in America and will increase our knowledge about the impacts of our daily exposures to music and noise," he added.

The hearing data will also be shared with the World Health Organization.

In the heart and movement study, Apple has partnered with Brigham and Women's Hospital and the American Heart Association to sort through a variety of data collected from customers. Researchers will try to make sense of mobility data (such as walking speed and daily stair climbs) and how it relates to outcomes such as hospitalizations, falls, and cardiovascular health.

"We are excited to be working with all the study participants and with Apple to identify the features of complex human physiology that lead to different outcomes in wellness or chronic disease, and to use this information to empower individuals to maximize their own health," Calum MacRae said in a statement. MacRae is the vice chair of Scientific Innovation for the Department of Medicine at Brigham and Women's Hospital and associate professor of medicine at Harvard Medical School.

Vital signs

Lastly, Apple is working with the Harvard T.H. Chan School of Public Health and the NIH's National Institute of Environmental Health Sciences (NIEHS) for a study on women's health. Researchers will "leverage participants' voluntary use of a smartphone research app" to collect data on menstrual cycles and gynecological health. That data is intended to better inform screening recommendations and risk assessments for things such as polycystic ovary syndrome (PCOS), infertility, osteoporosis, breast cancer, pregnancy complications, and menopausal transition, the researchers say.

In a press release, Harvard Chan School noted that:

Treating the menstrual cycle as a vital sign—comparable to blood pressure, temperature, pulse rate, and respiration rate—could lead to the earlier detection of many health conditions, both gynecological and systemic, as well as a better understanding of women's reproductive health and health needs across the lifespan.

Michelle A. Williams, a reproductive epidemiologist and dean of the faculty at the Harvard Chan School, noted in the release that women's health is chronically underfunded and poorly understood. "Women make up half of the world's population, yet even today there has been limited investment in studying their unique health needs," she said. "This study, unprecedented in scope, will greatly advance our understanding of the biological and social determinants of women's health, and lead to better health outcomes."

While the research partners are optimistic about the studies' potential to improve health, researchers will likely face hurdles—as they have in other mobile-device-based studies. Common trouble spots can include issues of data security and consent, low participant retention, missing data, and selection bias—that is, surveying health data from demographics likely to have pricey, newer gadgets. There have also been concerns of sensitive health-monitoring wearables and apps alarming healthy people and sending them to doctors to get unneeded screens and procedures.

Still, the more studies using this type of data, the more likely for such issues to get ironed out. And mobile-device-based study participants still have the potential to enroll more (as well as more diverse groups) than some standard studies. As the NIEHS noted in a release: "We want to do our part to make this new method of data collection a scientifically valid source of health information."

The three studies will be available through Apple's new Research App, which will be out later this year.

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