<prompt> Increased Reid index is classically associated with?Chronic BronchitisEmphysemaBronchiectasisInterstitial lung disease  <response>: The diagnostic feature of chronic bronchitis in the trachea and larger bronchi is enlargement of the mucus secretinggland . The magnitude of the increase insize is assessed by the ratio of the thickness of the submucosal gland layer to that of the bronchial wall the Reid index--normally 0.4. Chronic smoking causes submucosal gland hyperophy and hyperplasia, leading to a Reid Index of 0.5 indicating chronic bronchitis. 