Substudy Science View visual summaries for individual substudies Mental Health and Substance Use Substudy (PDF) Pulmonary Function Substudy (PDF) Hearing and Balance Substudy (PDF) Echocardiogram Substudy (PDF) Fibroscan® Substudy (PDF) Brief Cognitive Substudy (PDF) Full Cognitive Substudy (PDF) Tooth Count Substudy (PDF) Microbiome Substudy (PDF)