Asthma prevalence varies dramatically depending on the population and age group studied, research shows. The same also can be said about geographic location. Various national surveys have placed the prevalence of "current asthma" in U.S. adults between 7 percent and 8 percent.1,2 These estimates come from the Centers for Disease Control and Prevention's Behavioral Risk Factor Surveillance System (BRFSS) — the only national surveillance survey that provides state-by-state data on various health risk factors, including asthma. In 2002, asthma prevalence ranged from 5.8 percent in South Carolina to 10.0 percent in Maine.3 (See Figure, page 16.) This Figure demonstrates that the prevalence of adult "current asthma" varies from state to state and that this has changed slightly over the three years displayed.