Officials with a Davenport-based chiropractic school dispute a study that finds neck adjustments can significantly raise the risk of a stroke. Doctor Charles Henderson, a research scientist at Palmer College’s Center for Chiropractic Research, says the patients interviewed for the study were asked to recall information from years prior which could have led to flawed data, while the incidence of stroke was as high as two-million-to-one.Dr. Henderson says “This is an extremely rare occurrence. In fact, it’s so rare that it hasn’t really been determined whether manipulation actually caused the stroke.” The study, published in the journal “Neurology” found victims of a certain type of stroke caused by a tear in the neck artery were six times more likely to have had their necks manipulated within 30 days before the stroke. Henderson says chiropractors are aware of potential risks in this area and work very carefully to avoid them.It’s estimated 20-million Americans regularly get chiropractic care, including about a half-million Iowans. Dr. Henderson says manipulation of the neck and spine -is- safe when a professional is doing the work, but he says others who haven’t had the strict training could inadvertently make a move that could cause serious injury. Henderson says “If the neighbor next door does an adjustment or manipulation or someone that’s not trained, then they can be injured. That’s why one receives a considerable amount of training before you’re licensed to do these things.” Palmer College was established in Davenport in 1897, the nation’s first college of chiropractics. The Davenport campus has 17-hundred students and the college also has campuses in California and Florida.