TOPLINE:Heavy secondhand smoke (SHS) exposure is associated with severe headache or migraine in adults who have never smoked, with effects of exposure varying depending on body mass index (BMI) and level of physical activity, new research shows. METHODOLOGY:Investigators analyzed data on 4560 participants (median age, 43 years; 60% female; 71.5% White) from the 1999-2004 National...