Fourteen percent of US teens are vitamin D deficient, according to a study by Sandy Saintonge and colleagues at Weill Cornell Medical College.

In kids, vitamin D deficiency can cause abnormal bone mineralization and rickets. In adults, it is associated with cancer, cardiovascular disease, immune deficiency, insulin resistance and hypertension.

Estimates for the prevalence of vitamin D deficiency in the general population have been confounded by faulty measurement systems and a lack of expert consensus regarding optimal vitamin D levels.

In 2007, the 13th Workshop Consensus Group on Vitamin D made another pass at the latter, and ended up bumping the lower level of acceptable vitamin D levels by almost 50%.

That’s what prompted the current study.

The scientists obtained data from 2,955 participants between the ages of 12 and 19 that had been enrolled in the National Health and Nutrition Examination Survey III. Using the old criteria, only 2% of the population would have been classified as Vitamin D deficient.

The write-up is in Pediatrics.

Alarmingly, more than half of African-American teens were found to be deficient in vitamin D. Overweight teens were twice as likely as those in the normal-weight group to be Vitamin D deficient.

Girls were twice as likely to be Vitamin D deficient as boys, a particular concern since the condition may increase maternal and fetal risks should any become pregnant.

“To meet minimum nutritional requirements teens need to consume at least 4 glasses of fortified milk daily or its dietary equivalent. Other foods rich in vitamin D include salmon, tuna, eggs and fortified cereals. A vitamin supplement containing 400 IU of vitamin D is another alternative,” said Saintonge, an assistant professor of pediatrics.

People get attached to their Roombas.

They name their machines. They worry that repairs might change their Roomba’s personality. They paint them, dress them in costumes, even post videos of their Roomba in action.

Roboticists see opportunity in this behavior. If humans develop strong feelings about mindless floor cleaners, imagine how they might respond to “socially assistive” machines designed specifically to provide companionship and assistance to people; those with disabilities, for example.

Socially assistive robots, scientists hope, will one day assist stroke patients with rehab, stroll alongside dementia patients-perhaps helping them navigate hallways along the way, and help autistic kids improve interpersonal skills.

But they’ll reach their potential only if they can discern human emotion and intent, express something akin to feelings in response, and follow social conventions, according to Kerstin Dautenhahn, a professor at the School of Computer Science at the UK’s University of Hertfordshire.

“A socially ignorant robot always takes a direct path and interrupts at any point to do its task,” she explained to the Washington Post.

“But a socially (assistive) robot modifies its path to avoid getting too close to a human, waits until the right time to talk and fetches items without being asked.”

To accomplish this, new robots will use information obtained from sensors.

For example, motion detectors attached to the wrist allow robots to assess a human’s speed and direction. Heat sensors permit the robot to move toward or away from a warm body.

“People may be open to direct encouragement when they’re fresh and require more empathy when they’re tired,” notes Reid Simmons, a professor at Carnegie Mellon.

“So the robot may need to change its speech and expression, just as a therapist would.”