1. the Department of Health and Social Behavior, Harvard School of Public Health, and Channing Laboratory, Harvard Medical School (I.K.); the Normative Aging Study, Department of Veterans Affairs Outpatient Clinic (P.V.), and Channing Laboratory, Harvard Medical School (D.S., A.S.); and Channing Laboratory, Brigham and Women's Hospital, and Pulmonary and Critical Care Division, Beth Israel Hospital, and Harvard Medical School (S.T.W.), Boston, Mass.