Asthma is a lung disease which causes an inflammatory cascade that narrows the airways.  According to the national institutes of health close to 18 million US adults suffer from the disease.  Some of the common causes include: toxins, environmental factors and genetics.
One commonly overlooked cause is poor spinal health and postural misalignments.  Individuals who work on posture, and restore spinal alignment regularly report fewer complications associated with asthma symptoms.