Baltimore Longitudinal Study of Aging

* INCLUSION CRITERIA: These criteria pertain to the Screening Visit and Visit 1. If any of these conditions develop after this time, the participant remains in the study. In particular, participants who develop cognitive, motor or psychiatric conditions are retained in the study, although they are excluded from specific testing in which their underlying health condition is an exclusion criteria. Participants that refuse genetic testing and storage at Visit 1 will not be eligible to participate in the study. * Age greater than or equal to 20 years of age * Weigh less than or equal to 300lbs and/or body mass index (BMI) is less than or equal to 40 * Do not have established genetic diseases * Are able to perform daily self- care without assistance * Are able to walk independently for at least 400 meters without assistance and without developing symptoms * Are able to perform normal activities of daily living without shortness of breath (walking or climbing stairs) * Do not have cognitive impairment based on screening tests and in the absence of any drug treatment * Do not have a history of cardiovascular disease (including angina, myocardial infarction, congestive heart failure, cerebrovascular diseases, uncontrolled hypertension) * Do not have a history of diabetes (requiring any medical treatment other than diet and exercise) * Do not have active (any activity in the last 10 years) cancer, except for locally limited basal or squamous cell cancer * Do not have clinically significant hormonal dysfunction (Laboratory values out of range despite supplementation and/or drug treatment) * Do not have a history of neurological diseases or birth defects (other than minor anatomical abnormalities, which do not affect physical and/or cognitive function) * Do not have a history of kidney or liver disease (associated with reduced kidney or liver function) * Do not have a history of severe gastrointestinal (G.I.) diseases * Do not have muscle-skeletal conditions due to diseases or traumas (that cause pathological weakness and/or chronic pain) * Do not have a history of severe psychiatric conditions (associated with behavioral problems or requiring chronic medical treatment) * Do not have any medical condition that requires absolute and continuous need for long term treatment with antibiotics, corticosteroids, immunosuppressors, H2 blockers and/or proton pump inhibitors, or pain medications * Do not have important sensory deficits (legally blind and/or any condition that precludes the participant from being tested with standard neuropsychological tests or providing informed consent) * Able to read and speak English * Do not have joint replacements due to arthritic changes (joint replacements due to previous trauma are ok) or do not have 2 or more joint replacements for any reason * Do not meet any exclusionary criteria for 3T MRI and agrees to perform the test * Agree to genetic (DNA/RNA) sample collection, analysis, and storage at Visit 1 EXCLUSION CRITERIA: These criteria pertain to the Screening Visit and Visit 1. If conditions considered as exclusion criteria for study entry develop any time after the this, the participant remains in the study. Exclusion Criteria Based on Laboratory Assessment: * HIV virus infection * Hepatitis B or C * Syphilis * WBC \> 12,000/mcrL * Platelets \< 100,000 or \>600,000 /mcrL * Hemoglobin \< 11 g/dL * Creatinine \>1.5 mg/dl or calculated creatinine clearance \< 50 cc/min * Bilirubin \> 1.5 mg/dl (unless higher levels can be ascribed to Gilbert s disease) * ALT, AST or alkaline phosphatase twice the normal serum concentration * Corrected calcium \< 8.5 or \> 10.7 mg/dl * Albumin \< 3.1 g/dl