Adults with vitamin D levels below 20 ng/mL were significantly more likely to receive a fibromyalgia diagnosis during 10 years of follow-up than people with levels of 30 ng/mL or higher, though researchers stress that the large observational study cannot show that vitamin D deficiency causes the condition.
By yourNEWS Media Newsroom
A large analysis of electronic health records has identified a substantial association between low vitamin D levels and the later development of fibromyalgia, adding to longstanding research into possible connections between vitamin D, muscle function and chronic pain.
The study, published in Frontiers in Nutrition, examined records from more than 1.1 million adults and found that participants with vitamin D levels below 20 nanograms per milliliter, or ng/mL, had a 63% higher risk of being diagnosed with fibromyalgia over as long as 10 years of follow-up compared with adults whose levels were at least 30 ng/mL.
Researchers also reported a 30% higher risk of other chronic pain-related diagnoses among participants in the low-vitamin-D group.
The findings became more pronounced among people with the lowest vitamin D concentrations and in several specific subgroups, but the researchers repeatedly cautioned that the study establishes an association rather than cause and effect.
Dr. Elena Martinez, the study’s first author, said the results point to a potentially meaningful relationship that warrants additional investigation.
Fibromyalgia is a chronic condition characterized by widespread pain and can also involve fatigue, sleep disturbances and other symptoms. There is no single laboratory test that independently establishes the diagnosis, which is generally made through clinical evaluation.
Vitamin D, meanwhile, is involved in numerous physiological processes, including bone and muscle health, nervous system function and immune regulation. A 2021 article from Mercola.com has also discussed the vitamin’s broad biological role, while NaturalNews.com has previously highlighted pain among symptoms that may occur in people with vitamin D deficiency.
For the new analysis, investigators used de-identified electronic health information collected through the TriNetX Global Collaborative Network.
They identified 561,418 adults whose measured vitamin D concentrations were below 20 ng/mL and matched them with an equal-sized group whose concentrations were 30 ng/mL or greater.
The two populations were matched on factors including age, sex and existing medical conditions to reduce some of the differences that could otherwise distort the comparison.
Researchers excluded participants who already had chronic pain diagnoses before the analysis began.
They also imposed a one-year lag between the qualifying vitamin D blood test and the point at which a subsequent fibromyalgia diagnosis could be counted.
That approach was intended to reduce the possibility that participants already had undiagnosed fibromyalgia or chronic pain when their vitamin D levels were measured.
Over the follow-up period, the low-vitamin-D population was more likely to develop fibromyalgia.
The association was particularly strong among adults older than 65. In that group, low vitamin D was linked to a 76% greater risk of receiving a fibromyalgia diagnosis.
Risk also increased as measured vitamin D concentrations declined.
Participants with severe deficiency, defined in the study as levels below 10 ng/mL, had an 89% higher risk of fibromyalgia compared with the higher-vitamin-D reference group.
Another analysis focused on people whose low vitamin D status had been documented on two separate tests within a one-year period.
Those participants had a 97% higher risk of developing fibromyalgia, according to the study.
Researchers said that pattern — in which risk increased as vitamin D levels declined or remained repeatedly low — is consistent with what is known as a dose-response relationship.
Such a pattern can strengthen evidence of an association, but it still does not establish that the lower vitamin D levels were responsible for producing the disease.
The distinction is particularly important because numerous factors can affect both vitamin D status and chronic pain.
Physical activity, time spent outdoors, sun exposure, diet, obesity, underlying medical conditions and other lifestyle or health characteristics could influence vitamin D concentrations while independently affecting a person’s likelihood of experiencing pain.
It is also possible that early or unrecognized illness could change behavior in ways that lead to lower vitamin D levels.
“These findings do not mean low vitamin D causes fibromyalgia,” said co-author Dr. James Park in a statement. “Clinical trials are needed to determine whether correcting a deficiency changes risk.”
That question cannot be answered by examining health records alone.
A randomized clinical trial would be needed to determine whether raising deficient vitamin D levels actually reduces the likelihood of developing fibromyalgia or improves outcomes in people at elevated risk.
Researchers nevertheless noted several biological reasons the relationship is worth investigating.
Vitamin D contributes to muscle function and nervous system activity and participates in inflammatory and pain-signaling processes. Researchers have also studied associations between inadequate vitamin D status, impaired muscle performance and greater fall risk among older adults.
Previous research has similarly found a high prevalence of low vitamin D among some populations experiencing widespread or unexplained musculoskeletal pain.
A Mayo Clinic study cited in The Vitamin D Cure, for example, was reported to have found deficient vitamin D levels in more than 90% of patients studied for unexplained widespread pain.
Earlier research described by Dr. Michael Holick also examined Muslim women in Denmark who had muscle pain consistent with fibromyalgia and reported vitamin D deficiency among 88% of participants.
Those earlier findings, like the new analysis, do not by themselves demonstrate that deficiency caused the participants’ pain.
They do, however, contribute to a broader body of research examining whether vitamin D status may be one factor associated with musculoskeletal symptoms in some patients.
The new study’s authors therefore stopped short of recommending vitamin D supplementation as a preventive treatment for fibromyalgia.
The findings also do not support indiscriminately taking high-dose vitamin D.
Vitamin D status can be measured with a blood test, and people concerned about persistent muscle aches, fatigue or possible deficiency can discuss appropriate testing and treatment with a health professional. The importance of determining an individual’s level through blood testing has also been discussed in health programming on Brighteon.com.
Vitamin D can be obtained through sunlight exposure, certain foods and supplements, although the appropriate approach depends on an individual’s health status, diet, sun exposure and measured blood levels.
Some health advocates have noted that relatively few foods naturally provide large amounts of vitamin D, which is one reason supplementation is sometimes used when a deficiency has been confirmed.
Claims about the prevalence of inadequate vitamin D have also varied widely depending on the threshold used. Promotional material for The Vitamin D Solution, for example, previously cited an estimate that approximately 200 million Americans were vitamin D deficient.
For the current research, however, the most important finding is considerably narrower.
Across two matched groups totaling more than 1.1 million adults, vitamin D levels below 20 ng/mL were associated with substantially greater odds of later fibromyalgia and other chronic pain diagnoses, with the association becoming stronger among people with severe or repeatedly documented deficiency.
What remains unanswered is whether low vitamin D contributes directly to the development of fibromyalgia, serves as a marker for other underlying risk factors or reflects some combination of the two.
Until randomized trials address that question, the study supports closer scientific scrutiny of vitamin D and chronic pain but does not establish supplementation as a way to prevent fibromyalgia.
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