Overweight adolescents already struggling with risk factors such as insulin resistance may need to add weak bones to their list of health concerns, researchers report. A study of 143 overweight 14- to 18-year-olds showed those with risk factors such as the precursor for diabetes and low levels of the blood-vessel protecting HDL cholesterol have less bone mass — an indicator of bone strength — than their overweight but otherwise healthy peers, according to new research.