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A survey of school districts around the country finds that less than half test their water for lead, and among those that do more than a third detected elevated levels of the toxin, according to a federal report released Tuesday. Lead can cause brain damage and learning disabilities in children. (7/17)

Besides a cure, what do those afraid of Alzheimer's disease need most? According to entrepreneur and philanthropist Bill Gates, a key need is a "reliable, affordable, and accessible" diagnostic test. To jump-start that research, Gates announced today that he has joined a coalition of philanthropists who are investing $30 million to create a venture fund called Diagnostics Accelerator. "We need a better way of diagnosing Alzheimer's -- like a simple blood test or eye exam -- before we're able to slow the progression of the disease," Gates wrote in a statement announcing the investment. "Imagine a world where diagnosing Alzheimer's disease is as simple as getting your blood tested during your annual physical." (LaMotte, 7/17)

CTE has been part of the national lexicon in the U.S. since the 2015 movie Concussion dramatized the discovery of this degenerative brain disease among football players. Chronic traumatic encephalopathy is found among people who've had head injuries. Though not everyone with head trauma develops CTE, the group that's come to be most associated with it is football players, whose brains can be routinely jarred by hard hits. The disease has been linked to depression, dementia and even suicide among those who play the game. (Goldman, 7/17)

Another key patent on the CRISPR genome editing technology is facing a legal challenge. On Tuesday, St. Louis-based Benson Hill Biosystems, a privately held agriculture biotech company, filed a petition for post-grant review with the U.S. Patent and Trademark Office, arguing that a CRISPR patent granted to the Broad Institute of MIT and Harvard in 2017 and licensed by Editas Medicine (EDIT) is invalid. (Begley, 7/17)

A daily dose of baby aspirin is widely recommended for heart disease prevention, but a one-dose-fits-all approach may not work. A new analysis, in The Lancet, looked at data from 10 randomized trials and found that the size of the dose and the weight of the patient have significant effects on outcome. Researchers found that a daily dose of 75 to 100 milligrams of aspirin lowered the risk of cardiovascular events by 23 percent for people weighing less than 154 pounds, but had no effect in those weighing more. In people over 154 pounds, low-dose aspirin increased the risk for a fatal cardiovascular event. (Bakalar, 7/17)

It looks like a flash drive, can be hidden anywhere and doesn't create tell-tale smoke. Across the country, the use of these e-cigarettes are spiking among youth, but parents often aren't even sure what they are and many teens mistakenly believe there are no serious health risks. (Cardoza, 7/17)

Should we stretch before exercise? A thought-provoking new experiment with athletes suggests that the answer could depend on how we feel about stretching and what kind of exercise — and stretching — we intend to do. (Reynolds, 7/18)

A good night’s sleep may be critical for the metabolic health of teenagers. Researchers studied 829 boys and girls, average age 13, who wore electronic measuring devices that tracked sleep time, sleep quality and physical activity over seven to 10 days. They also recorded five factors associated with cardiovascular risk: waist circumference, blood pressure, HDL or “good” cholesterol, triglycerides and insulin resistance. (Bakalar, 7/17)

On her way to the orthopedic clinic, April Jorgenson steeled herself for a lecture. She was bringing in her 5-year-old son, Rusty Golaski, to see if he had broken his arm while jumping on the trampoline in the family’s Hugo backyard. “I thought I’d get some backlash from the doctor when I told him what happened, but he didn’t say a thing,” said Jorgenson, 34. “He just told me not to let Rusty jump while his cast is on.” (Burger, 7/17)

A new mapping technology is helping doctors determine where to place life-saving catheters in patients with irregular heartbeats without the use of radiation. It’s being used at Florida Hospital. One of these patients is 14-year-old Grayson Abraham who has a heart condition that can cause sudden cardiac death in young athletes. (Prieur, 7/18)

The National Institutes of Health announced Tuesday that it is launching a nationwide study on aggressive prostate cancer in African-American men. The study will be one of the first to analyze how social stressors such as discrimination, lack of health care access, and segregation interact with genetic changes in African-American men with prostate cancer. (Eppolito, 7/17)