The proportion of children and working-age Americans who went without a prescription drug because of cost concerns jumped to one in seven in 2007, up from one in 10 in 2003, according to a study released by the Center for Studying Health System Change and funded by the Robert Wood Johnson Foundation. Rising prescription drug costs and less generous drug coverage likely contributed to the growth in nonelderly Americans who went without a prescribed medication because of cost concerns—from 10.3% in 2003 to 13.9% in 2007, according to the findings. The most vulnerable people—those with low incomes, chronic conditions and the uninsured—continue to face the greatest unmet prescription drug needs, the study found.