High Reid index is indicative of the disease of-

Reid's index is a ratio between the thicknss of the submucosal mucus secreting glands and the thickness between the epithelium and cailage that covers the bronchi. Normal Reid's index is less than 0.4, the thickness of the wall is always more than double the thickness of the glands it contains. Chronic smoking causes submucosal gland hyperophy and hyperplasia, leading to a Reid's index of >0.5 indicating chronic bronchitis. Chronic bronchitis can be defined as a chronic productive cough lasting more than 3weeks. have a higher predisposition to develop chronic bronchitis. In chronic bronchitis, Reid's index is increased. Ref Davidson edition23rd pg 574