September 1, 2023 – The future of public health could be in your hands – or on your wrist, to be precise.
Researchers are using smartwatches and fitness trackers to conduct rigorous large-scale studies that would have been impossible in the past. It’s a growing trend that could greatly increase our knowledge about a range of diseases.
“There is truly no disease that is not impacted by this type of research,” said Calum MacRae, MD, PhD, vice chairman of scientific innovation in the Department of Medicine at Brigham and Women’s Hospital.
Wearables are already used for research into cardiac, respiratory, neurological and liver diseases, as well as gynecological conditions, certain types of cancer, diabetes, sleep quality, autism and mental disorders.
In a recent example, as many as 1 million iPhone and smartwatch users can sign up to share data about their menstrual cycle and other health and lifestyle factors like sleep and stress. 100,000 people have already registered Apple Women’s Health Surveya ten-year project between Harvard, Apple and the National Institute of Environmental Health Sciences (NIEHS) that is unprecedented in size and scope.
Doctors know that an irregular menstrual cycle can be a sign of many things, from infertility to heart disease, diabetes and even cancer. Many doctors believe that menstrual history should be considered an essential sign, just like heart rate or blood pressure, but they say menstrual and reproductive health is woefully underfunded and understudied.
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With a larger, more diverse sample of people being studied, researchers hope to advance the diagnosis and treatment of health problems associated with menstrual cycle disorders.
“We can ask questions that we couldn’t ask before,” says Shruthi Mahalingaiah, MD, one of the study’s principal investigators and assistant professor of environmental, reproductive, and women’s health at the Harvard TH Chan School of Public Health.
The rise of wearables
Nearly half of Americans wear smartwatches or fitness trackers, according to a survey Survey 2022. In addition to the number of calories and the number of steps, the technology can provide information – via smartphone apps – about breathing rate, heart rate, blood oxygen levels and sleep duration.
Academic medical centers work with digital giants like Apple, Google, Samsung, Alphabet and Amazon, as well as tech startups and nonprofits. The coronavirus pandemic accelerated the trend, as medical institutions tested wearables to monitor patients from home. Symptom checkers and outbreak apps helped monitor exposure to infections and identify hotspots, showing how large data sets could be captured in a consistent way.
Studies using wearables for data collection account for less than 1% of all studies worldwide. But that number is growing and has increased by several hundred in recent years, according to clinicaltrials.gov (the National Library of Medicine’s clinical trial registry).
This trend goes beyond the wrist and uses ‘smart’ glasses, rings, necklaces, ‘hearables’ and even clothing. And the growing universe of medical-grade wearables is helping too: smart patches that record vital signs, blood pressure monitors and continuous glucose monitors, which are often prescribed by doctors but also available from retailers.
“You can live anywhere in the country and participate in research using wearables,” says Ray Dorsey, MD, professor of neurology at the Center for Health Technology at the University of Rochester Medical Center in New York. Volunteers previously had to travel to medical centers for tests and updates, which often limited the scope of the studies.
Big technology, big studies
In recent years, tech companies like Apple, Samsung and Google have introduced and refined open-source platforms that allow researchers to build apps and tools that can securely capture health information from people using wearables.
In 2015, a smartphone app developed by Dorsey’s URMC team and partners used Apple’s ResearchKit in a study of Parkinson’s disease. The researchers enrolled more than 2,000 volunteers per day, an unheard of number at the time. Ultimately, more than 9,000 people took part in the study, performing tasks such as walking to measure gait changes. The published findings helped researchers better understand how Parkinson’s symptoms varied from day to day, Dorsey said.
In 2017, together with the Stanford University School of Medicine, more than 400,000 Apple Watch users from all 50 states participated in the Apple Heart Study in just eight months. The study found that smartwatches could identify irregular heart rhythms, such as atrial fibrillation. It also paved the way, along with a second study, for the FDA to classify the watcheselectrocardiogram (EKG) app as a medical device. Since then, smartwatch ECG apps from Fitbit, Samsung and Garmin have received similar approvals.
The Apple Women’s Health Study launched in 2019, along with two other ambitious projects: the Apple Heart and Movement Study, led by MacRae at Brigham and Women’s Hospital, with the American Heart Association; and the Apple Hearing Study at the University of Michigan.
The Apple Women’s Health Study uses a larger mix of people based on race, ethnicity, age, socioeconomic position and location, compared to the much smaller range of previous studies. The data collected covers exercise, sleep, and environmental and behavioral factors, and monthly surveys capture personal data that the sensors cannot capture.
“This gives us the opportunity to include very detailed information in our analyses,” says Huichu Li, PhD, co-author and research fellow at the Harvard School of Public Health.
Among the first results: the slightly longer menstrual cycles possibly caused by COVID vaccines turned out to be temporary. Speaking more generally, irregular and infrequent periods were found to be more common in the black and Asian people studied, while menstrual cycles were longer in Asian, Hispanic and overweight people.
An analysis of more than 50,000 people provided insight into the link between abnormal periods and health problems such as polycystic ovary syndrome, endometrial hyperplasia and cancer.
“Future studies will delve deeper into the data and look at the impact of environmental exposure, behavior and stress on the menstrual cycle,” Mahalingaiah said.
Challenges and the future
The promise of wearables is tempered by challenges. Much more testing is needed to ensure that the devices provide clinical-quality data. Concerns about privacy and cybersecurity threats remain in the healthcare industry, according to research from professional services firm Deloitte.
These new types of research have their limits. People need to own smartwatches and smartphones, technology that is less common in underrepresented populations and rural areas, and they need to have reliable internet access.
But increased adoption of the devices – by consumers and healthcare providers – means the trend is likely to grow.
“I don’t see a world where this kind of research slows down,” said Urvi Shah, senior manager at Deloitte Consulting’s Life Sciences and Health Care Practice.