People with cholestrol problems from anywhere in Iowa are encouraged to sign up for a free series of health studies through the University of Iowa. Dr. Hal Schrott says cholesterol can be a silent killer and test subjects may have a shot at a much better, longer life.Dr. Schrott is director of the U-of-I’s Lipid Research Clinic. He says the studies will evaluate and compare the effectiveness and safety of different cholesterol-lowering medications alone and in combination with other drugs. He wants to recruit adults of virtually all ages for the series of tests.Test subjects will be compensated for taking part in the studies, based on the distance they have to travel to Iowa City. He says there may be many trips involved over several months.For more information, call (800) 887-6917.