Smokers who cut back on cigarettes may not necessarily be curtailing the amount of toxic substances they inhale. Heavy smokers who light up less often still breathe in at least two times more toxic substances per cigarette than light smokers, according to a study by Dorothy Hatsukami and her colleagues at the University of Minnesota. Evidently, when heavy smokers puff on fewer cigarettes, they compensate for lower levels of nicotine by inhaling more deeply or longer on each one. The study supports earlier epidemiological work that revealed that individuals who cut the number of cigarettes they smoke do not have decreased health risks. “The bottom line is there may not be any health benefit to reducing the number of cigarettes,” Hatsukami says. If smokers want to reduce their risk of cancer and disease, she adds, they “need to stop smoking.” The study appears in the December 2006 Cancer Epidemiology, Biomarkers and Prevention.