• Unified Parkinson's Disease Rating Scale (UPDRS) change [ Time Frame: Baseline, 6 month, 12 month and 18 months ]
  This is the Unified Parkinson's disease rating scale assessment. The investigators assess I, II, III and V components of the UPDRS. UPDRS 3 is motor skills.
• Mini-Mental State Examination (MMSE) change [ Time Frame: Baseline, 6 month, 12 month and 18 months ]
  It captures mental status and awareness of time, place and surrounding.
• Stroop test change [ Time Frame: Baseline, 6 month, 12 month and 18 months ]
  It captures understanding of color and its description within a certain time frame when letters and colors do not match. There are only two choices to pick from and the correct choices should be made to proceed to the next one. Correct choices are given one point and incorrect choices delete one point. Maximum score is desired within given time. Three initial trials are given to understand the test.
• Sleep test change [ Time Frame: Baseline, 6 month, 12 month and 18 months ]
  This requires an instrument Zeo sleep monitor. Subjects are given instructions how to use it. Sleep sensor patches are supposed to be applied on forehead before going to sleep and the data of quality of sleep is captured overnight.
• Macrophage and cytokine changes [ Time Frame: Baseline, 6 month, 12 month and 18 months ]
  The blood is tested to report GPR109A levels in macrophages in M1 and M2 populations. Inflammatory and anti-inflammatory cytokine levels are measured in plasma.
• Niacin changes [ Time Frame: Baseline, 6 month, 12 month and 18 months ]
  Plasma and urine samples will be tested to report levels of niacin and its metabolites.
• Cerebrospinal Fluid (CSF) changes [ Time Frame: Baseline, and 18 months ]
  Inflammatory and non-inflammatory cytokines levels will be tested in CSF at baseline and 18 months after intervention.

Number of people affected by Parkinson's disease is increasing each year. Vitamin B3 (Niacin/Niacinamide) supplement can be used to slow the progression of PD.

Inflammation plays a central role in Parkinson's disease (PD) pathology as evidenced by the presence of microglia in the substantia nigra in post-mortem samples as well as activated microglia and cytokines in clinical and animal studies. The use of non-aspirin non-steroidal anti-inflammatory drugs was found to reduce the risk of PD. The investigators recently identified an anti-inflammatory receptor GPR109A that is upregulated in PD. Niacin has a high affinity for this receptor, suggesting that it (niacin) may play an important role in reducing inflammation in PD. The investigators also found that individuals with PD have a chronic niacin deficiency. In a three month trial at Augusta University (the investigators' affiliate) the investigators demonstrated that niacin was helpful for PD patients in reducing inflammatory macrophages and boosting the anti-inflammatory macrophages in blood.

In this VA-funded study, the investigators will determine the effect of 18 months over-the-counter (OTC) niacin or niacinamide supplementation on inflammation (as assessed in the blood and spinal fluid) and severity of the PD symptoms.

• Dietary Supplement: Niacin
  100mg tablets twice daily
  Other Name: Vitamin B3, Nicotinic acid
• Dietary Supplement: Niacinamide
  100mg tablets twice daily
  Other Name: Vitamin B3, Nicotinamide
• Other: Placebo
  Placebo tablet

• Active Comparator: Group 1 ? Niacin Arm
  Oral 100 mg fixed dose twice daily x 18-months (200 mg total / day) with assessments @ baseline, 6 month, 12 month and 18 months
  Intervention: Dietary Supplement: Niacin
• Active Comparator: Group 2 ? Niacinamide Arm
  Oral 100 mg fixed dose twice daily (200 mg total / day) x 18-months with assessments @ baseline, 6 month, 12 month and 18 months
  Intervention: Dietary Supplement: Niacinamide
• Placebo Comparator: Group 3 ? Placebo Wait-listed Arm
  Oral placebo twice daily x 18- months with assessments @ baseline, 6 month, 12 month and 18 months
  Intervention: Other: Placebo

Inclusion Criteria:

• PD subjects will be adult men and women diagnosed with idiopathic mild to moderately severe PD
• The majority of PD subjects are expected to be > 60 years old
• Disease severity is defined as modified Hoehn & Yahr Stages I-IV (while "On")
• PD is defined according to the UK Brain Bank Criteria made at least six months prior to recruitment to the study

• PD features include the presence of at least two of the four cardinal clinical manifestations of the disease, which are:

  • tremor
  • rigidity
  • bradykinesia
  • disturbances of posture or gait, without any other known or suspected cause of Parkinsonism
• Subjects should be stabilized on PD medication for at least 3 months before enrollment into the study
• Subjects' PD drug prescriptions will not be altered nor withheld during the study
• The patient will have signed informed consent

Exclusion Criteria:

• Subjects will be excluded if they present with significant cognitive deficits
• A MMSE score of 25 is considered substantial global cognitive impairment

• Subjects will be excluded if they had previous brain surgery or other severe neurological problems

  • intracerebral hemorrhage
  • traumatic brain injury
  • central nervous system malignancy
  • active central nervous system (CNS) infection
  • significant stroke
  • Alzheimer disease or any type of implanted stimulator including but not limited to Deep Brain Stimulator (DBS) or pacemaker

• All subjects must be without evidence of dementia

  • defined as a score > 24 the Mini-Mental State Examination and able to understand test instructions
• Subjects must not have functional blindness (inability to participate in gait and visuomotor assessments) or lower limb amputation higher than the forefoot or any orthopedic problem that precludes performance of physical tests
• Subjects must not have known allergy to vitamin B3

• Significant cardiac, pulmonary, hepatic, gastrointestinal, renal disease, or uncontrolled/advanced diabetes are also exclusionary factors, e.g.:

  • New York Heart Association Class III or IV congestive heart failure
  • endocarditis
  • pulmonary insufficiency symptomatic at rest or with mild physical exertion
  • acute or chronic hepatitis
  • renal failure requiring dialysis
  • second and third degree atrioventricular (AV) block
  • sick sinus syndrome
• Subjects will be excluded if they are taking B3 but will be included if they are taking B complex that has very low dose B3 (25 mg) which has minimal effects on GPR109A (based on our unpublished observation)
• Overall, the investigators will exercise clinical judgment to exclude a subject from the study if, in the investigators' opinion, that a patient presents with a set of comorbidities which renders unsuitability for the study