There are so many questions that baffle health researchers. Like why a medication works for one person but does nothing for someone else. Or why a person with a healthy lifestyle gets sick when someone who doesn't exercise or eat well does not. Or why one sibling develops a disease while another is fine.

In an effort to prevent and treat disease based on the individual, researchers are recruiting 1 million people to share their health data. The National Institutes of Health's "All of Us" research project is focusing on "precision" medicine, versus one-size-fits-all health care plans.

"So much of what we have done in medicine over the years has not taken into account individual differences," says Dr. Francis Collins, NIH director, in a video explaining the study. "We're really building a fundamental base of knowledge about how humans stay healthy or get sick or what to do about it. I think the practice of medicine will be altered in profound ways."

The study hopes to learn how lifestyle choice, genes and environment all play a part in an individual's health and disease risks. Typically, health studies enroll several hundred or thousand participants, so the large-scale nature of this project "will be an unprecedented resource for researchers working to understand all of the factors that influence health and disease," says Collins.

Getting involved

About 2,500 participants have been enrolled so far as beta testers the study, according to the Associated Press. In this invitation-only pilot phase, participants have answered questions and given blood samples at some 50 sites around the country, such as pharmacies and blood banks.

If beta testing goes well, NIH plans to open the study in spring 2018 to adults around the country. If you participate, you'll be asked to answer questions about your health, family, home and work environments. If you have an electronic health record, you may be asked for access. You may also be asked to occasionally go to a local clinic or pharmacy to measure your weight, height, blood pressure and heart rate. You may also be asked for blood and urine samples (but that's not necessary to participate).

Volunteers will receive the results of their tests and any information researchers learn about them, which they can then share with their doctors.

NIH is hoping that participants (who can sign up online) will be in this for the long haul. They study lasts for an impressive 10 years.

"The All of Us Research Program will change the way we do research," says Collins. "Participants will be partners in research, not subjects, and will have access to a wide range of study results. What we’re doing with the All of Us Research Program is intersecting with other fundamental changes in medicine and research to empower Americans to live healthier lives."

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.