Inclusion Criteria:

• populations with neurological disorders
• healthy volunteers (controls)

Exclusion Criteria:

• The subject is excluded if they:

  • are legally or mentally incapable of comprehending and consenting to participate in the study
  • have a history of or exhibit indicators of metabolic bone disease, including the following: Hypoparathyroidism, primary hyperparathyroidism, recent hyperthyroidism (within the last six months), Paget's disease of bone;
  • grade 3 or 4 pressure ulcers present;
  • has undergone treatment with pharmacological agents influencing bone metabolism prior to the initial bone density assessment, including the following: bisphosphonates in the year prior to the bone density assessment ; parathyroid hormone in the year prior to the research ; estrogens, selective estrogen receptor modulators (SERMs), tibolone, or anabolic steroids within the preceding six months.
  • Thyroid drugs are permissible only if the dosage has remained consistent for the preceding six weeks and TSH levels are within the normal range.
  • Corticosteroid medication exceeding 7.5 mg of prednisone orally per day for a duration exceeding one month within the past six months.
  • Immunosuppressant therapy within the past year;
  • Vitamin A therapy above 10,000 IU per day or Vitamin D exceeding 5,000 IU per day.
  • Participants are prohibited from consuming additional vitamin D supplements exceeding 400 IU per day or traveling to regions with heightened sunshine exposure during the trial.