Hormonal protection from type 2 diabetes. About 9 million children over the age of six are considered obese, and this number is rising. [i]   As teenagers are becoming fatter, they are beginning to develop diseases once seen only in adults, such as type 2 diabetes and cardiovascular disease. One of the early warning signs of impending type 2 diabetes is insulin resistance, or the body’s reduced ability to use insulin to process blood sugars. However, not all overweight teens with equal levels of body fat develop insulin resistance, leading researchers to question if something other than body fat triggers this condition. In a recent study, NICHD-supported researchers found that overweight teens who had not developed insulin resistance were different in two ways: 1) they stored less fat around the body organs and in muscle cells, and 2) they had higher levels of adiponectin, a hormone secreted by fat cells and appears to protect against type 2 diabetes. These findings provide important new insights about key factors that may determine insulin sensitivity and how insulin resistance develops as children become overweight. Such knowledge should help to refine prevention and intervention strategies that target the physiological factors associated with the epidemic of childhood obesity and its associated rise in type 2 diabetes.

Gender of teen passenger can increase risky teen driving behaviors. Motor vehicle crashes end more young lives than any other cause of death for 15 to 20 year olds. [ii]   Teen drivers are involved in three times as many crashes, [iii] and crash rates among teens increase when teenage passengers are in the car. [iv]   Despite these facts, few rigorous studies clarify the specific factors that contribute to these grim statistics. NICHD researchers examined how having other teens in the car could influence two factors—speed and following distance—that contribute to risky driving behaviors. Using video and a laser-assisted radar device, the researchers recorded and studied 3,000 vehicles as they left 10 different high school parking lots and again a short distance away. Of the vehicles, 471 were driven by teens. The researchers found that, overall, teens drive faster and closer to the car in front of them than does general traffic. Moreover, the teen drivers’ speed increased significantly with a male passenger in the car: a quarter of the drivers exceeded the speed limit by at least 15 miles per hour when accompanied by teenage males. Conversely, male teens were less likely to tailgate or speed with a female teen passenger. These findings provide data that can help parents to set limits that could save teen lives.