According to a survey from Opinion Research Corporation, 78 per cent of American parents are not aware that signs of heart disease begin developing during childhood. As heart disease remains the United States' leading cause of death, there is a concerted emphasis on reducing risks early in life through lifestyle changes such as exercises, and proper diet. According to the survey, three-fourths of parents have never had their children's cholesterol levels checked. Dr. Margo Denke, a professor of medicine at the University of Texas Southwestern Medical Centre in Dallas published a study to address heart disease risk in young individuals in the "Journal of the American Medical Association" (JAMA). She has twice served on the panel of researchers who developed NHLBI's latest guidelines for prevention and treatment of high cholesterol. Dr. Denke conducted the first-ever study with biological families, and confirmed that simple dietary substitutions, from saturated fat diet to unsaturated fat diet, do make a difference in lowering cholesterol levels in both children and adults.