Here's an interesting project a Track Your Plaque Member brought to my attention: Grassroots Health.
Carole Baggerly, Director of GrassrootsHealth, is a breast cancer survivor who has engineered an impressive project to collect and tabulate vitamin D blood levels in thousands, perhaps millions of people, over the next 5 years. Anyone can participate at a cost of $30 twice a year to get a vitamin D home test kit. (A fingerprick is required. I've tried the test kit--it's easy and painless to use.) They simply ask you to provide some basic health information that will be accumulated and analyzed.
Here's a graph they feature on their website showing the vitamin D blood levels distributed among the first 300 participants:
(Click to enlarge.)
Ms. Baggerly is apparently working with vitamin D pioneer, Dr. Reinhold Vieth, of the University of Toronto.
This sounds like a really great idea. Should you enroll, please come back here and let us know about your experience.