Vitamin D Deficiency and Replacement on Pulmonary and Endocrine Function in SCI

Vitamin D deficiency is prevalent in individuals with Spinal Cord Injury (SCI). Recent studies have linked vitamin D with the prevention and/or treatment of a wide range of diseases, including chronic lung diseases. Patients with chronic lung diseases appear to be at increased risk for vitamin D deficiency for reasons that are not clear. Chronic lung diseases such as asthma and chronic obstructive lung disease (COPD) have been linked to vitamin D on a genetic basis. A recent observational study found a significant association between vitamin D deficiency and decreased pulmonary function in a large able-bodied population. The exact mechanisms involved have not been identified, but it has been postulated that vitamin D possesses a range of anti-inflammatory properties involving modulation of oxidative stress, or, possibly, protease/antiprotease balance and tissue damage/repair, mechanisms that have been shown to be important in the pathogenesis of chronic lung diseases. The relationship between vitamin D and the immune system is of utmost importance given that individuals with high cervical lesions express many obstructive aspects of pulmonary physiology commonly observed in individuals with asthma, in whom airway inflammation represents an underlying pathophysiological mechanism.

In addition to a high prevalence of vitamin D deficiency, persons with SCI have a higher prevalence of insulin resistance (IR), impaired glucose tolerance (IGT) and diabetes mellitus (DM). In the general population, vitamin D deficiency has been shown to be associated with IR, IGT and DM. If treatment of vitamin D deficiency in persons with SCI is shown to be associated with improvement in insulin sensitivity and reductions in impaired glucose tolerance or DM, then progression to more severe carbohydrate disorders may be delayed or prevented.

Part 1: Screening for Vitamin D Deficiency

Inclusion criteria

• Between the ages of 18 and 75,
• Chronic (>1 year) SCI; tetraplegia (C3-8), paraplegia, (T1-6)

Exclusion criteria

• Acute illness
• Acute drug or alcohol use
• Lack of mental capacity to give informed consent,
• Pregnancy,
• Currently receiving Vitamin D supplementation.

Part 2A: Vitamin D and Pulmonary Function

Inclusion criteria

• Between the ages of 18 and 75,
• Chronic SCI (>1 year, C3-T6)
• Vitamin D deficiency as defined as a value <20 ng/ml.

Exclusion criteria

• Smoking, active or history of smoking during life time,
• Any history of blast injuries to the chest,
• Active respiratory disease,
• Pregnancy,
• Lack of mental capacity to give informed consent.
• Recent (within 3 months) respiratory infection.
• Receiving medications known to alter airway caliber.
• Acute drug or alcohol use,
• Currently receiving Vitamin D supplementation > 1000 units/day.

Part 2B: Vitamin D, Carbohydrate Metabolism, and Insulin Resistance

Inclusion criteria

• Between the ages of 18 and 75,
• Chronic SCI (>1 year, C3-T6)
• Vitamin D deficiency as defined as a value <20 ng/ml,
• Insulin Resistance (IR), Impaired glucose tolerance (IGT), and/or Diabetes Mellitus (DM).

Exclusion criteria

• Pregnancy,
• Problems with the kidneys,
• Lack of mental capacity to give informed consent,
• Acute drug or alcohol use,
• Currently receiving Vitamin D supplementation > 1000 units/day.