Vitamin D is back in the media (The Examiner, Friday 19th February 2021). But in reality it should never have gone away! The question is still the same, namely, that Vitamin D can be an important factor in the prevention and recover from chronic illness. COVID is the new illness and there is renewed interest in Vitamin D for this reason.
In fact, Pain Relief Ireland recognised and raised this issue in our news blog almost 3 years ago (July 2018 (https://www.painreliefireland.ie/blog/sunshine-vitamin-d-and-chronic-pain-what-link)) . The focus in the last few months has being on the possible role for Vitamin D In COVID. It is important that the use of vitamin D in chronic pain is not forgotten.
Vitamin D levels are important!
There is no doubt that vitamin D plays a vital physiological role in the human body. While associations between insufficient and deficient levels of vitamin D and poorer health outcomes have been established, the relationship between vitamin D and chronic pain is less well understood. Indeed, no definitive mechanism exists to explain how vitamin D influences chronic pain development. Given the prevalence of vitamin D deficiency in chronic pain patients, supplementation may offer numerous health benefits.
Dr. Dominic Hegarty (Clinical Director Pain Relief Ireland) points out that “Individuals with chronic pain may be at increased risk of vitamin D deficiency, especially if they are obese, likely to have reduced sun exposure, low levels of physical activity, diets low in vitamin D-rich foods, or malabsorption issues. Anticonvulsants and steroids commonly used to treat chronic pain and rheumatic conditions (e.g. fibromyalgia) can reduce vitamin D levels” The literature would tend to support this opinion. (Looker A, Dawson-Hughes B, Calvo M, et al. Serum 25-hydroxyvitamin D status of adolescents and adults in two seasonal subpopulations from NHANES III. Bone 2002; 30: 771–777)
Prevalence of vitamin D deficiency among chronic pain patients
While general population estimates of deficiency have come from large population studies, evidence of the prevalence of vitamin D deficiency [serum 25(OH)D levels ⩽50 nmol/l] in rheumatic and chronic pain populations generally come from smaller clinic-based studies. Prevalence of hypovitaminosis D was found to be 86% in a Swiss rheumatology outpatient population. Estimates range from as high as 93% among individuals with persistent, nonspecific pain and as low as 26% in a sample of chronic pain patients being treated at a pain clinic. In fact in Irish adults serum vitamin D levels are recognised as been below average. (McCartney et al. 2020)
Indeed, among consecutive new patients in a rheumatology clinic, the prevalence of vitamin D deficiency was 70% [serum 25(OH)D ⩽53 nmol/l] and severe deficiency was 26% [serum 25(OH)D ⩽25 nmol/l], with deficiency among Musculoskeletal (MSK) conditions associated with chronic pain as follows:
- inflammatory joint diseases/connective tissue diseases, 69%;
- soft tissue rheumatism, 77%;
- osteoarthritis, 62%;
- nonspecific musculoskeletal back pain, 75%;
- osteoporosis, 71%.
Results from an audit of 25(OH)D in rheumatology outpatients indicate that levels were lower among rheumatology patients when compared with osteoporotic/osteopaenia patients, with the lowest levels found in inflammatory arthritis and fibromyalgia/chronic pain patients overall.
Although there is no concrete evidence that vitamin D supplementation is an effective treatment for chronic pain, no contraindications for the use of vitamin D supplementation among chronic pain patients exist, as vitamin D poses a low health risk in general, is generally well accepted, and is inexpensive.
Appropriate vitamin D supplementation should be recommended where levels are either insufficient or deficient according to the individuals’ additional risk factors (e.g. current medications, obesity level, and exposure to sunlight). A target of serum 25(OH)/D levels of >50nmol would be regarded as minimum.
Relevance of Vitamin D to Covid-19
With regard to Covid-19, it is salient that while the virulence mechanisms of this virus have not been fully characterised, a number of molecular virulence mechanisms including dipeptidyl peptidase-4 receptor (DPP-4/CD26) binding, Papain-like protease (PLpro)-mediated replication, MDA5 and RIG-I host-recognition evasion, and disruption of M-protein mediated type-1 IFN induction have been identified in the closely-related Covid-MERS virus . Of these, human DPP-4/CD26 has recently been shown to interact with the S1 domain of the COVID-19 spike glycoprotein, indicating that it may also be an important virulence factor in Covid-19 infection . Dr. McCartney (Ir Med J; Vol 113; No. 4; P58) highlighted that DPP-4/CD26 receptor expression has been shown to be significantly reduced in vivo upon correction of vitamin D deficiency . There is also evidence that optimisation of vitamin D may attenuate some of the critical downstream immunological sequelae thought to elicit poorer clinical outcome in Covid-19 infection, such as prolonged interferon-gamma response, and persistent interleukin 6 elevation, a negative prognostic indicator in acutely-ill pneumonia patients, including those with Covid-19.
Vitamin D management
Dr. Hegarty highlighted the following necessary steps to improve your Vitamin D levels and by doing so, possibly improve pain levels:
- The first step is to determine if your Vitamin D levels are low. If you are deficient, several months of high dose supplementation is required to achieve a normal level. This requires evaluation with a physician who is familiar with managing chronic pain, guidelines for Vitamin D supplementation, use of appropriate medication, etc.
- Typical doses range between 20-50ug/day Vitamin D
- Once you achieve normal levels, sunlight is the maintenance dose for anyone under 50 (over the age of 50, daily oral medication is required).
- For people with fair skin, fifteen minutes of direct sunlight to the face and arms twice a week in the spring and summer (longer in fall and winter) is sufficient to maintain Vitamin D levels.
- For people with darker skin, less vitamin D is produced with sunlight, so one hour a day of direct sunlight exposure may be needed.
- Make sure to get direct sunlight exposure before applying sunblock, as even an SPF of 8 will reduce vitamin D production by 95%.
- Discuss the options with your GP before-hand.