Fibromyalgia Linked to Deficiencies in RBC Magnesium, IGF-1
September 22, 2015
NATIONAL HARBOR, MD — Patients with fibromyalgia show deficiencies in red blood cell (RBC) magnesium and insulin-like growth factor 1 (IGF-1), a small study shows, suggesting potential clues to underpinnings of the condition and avenues for treatment.
In a condition that is challenging to treat and complicated by the subjectivity of pain, identifying such deficiencies can represent important, objective measures of abnormalities with definable treatment goals, lead author Thomas J. Romano, MD, PhD, a pain specialist based in Martins Ferry, Ohio, told Medscape Medical News.
“Fibromyalgia is a disorder that is notoriously devoid of objective markers,” he said.
“In identifying a comorbidity that can be objectively verified, you can let patients know that one of the reasons they could be having problems is because of these abnormal levels. Restoring those levels to where they should be, we have found, can truly turn people’s lives around — they have more stamina and more energy,” Dr Romano said.
Their research was presented here at the American Academy of Pain Management (AAPM) 2015 Annual Meeting.
Having reported on low RBC magnesium levels among his patients with fibromyalgia back in the 1990s, Dr Romano noted some previous studies also linking low IGF-1 to the condition and sought to further investigate whether the two comorbidities were often related.
He enrolled 60 patients with confirmed fibromyalgia: 10 men with a mean age of 49.5 years and 50 women with a mean age of 42.8 years.
In tests evaluating IGF-1, the patients as a group had a mean IGF-1 level of 59.33 ng/dL, which is lower than the mean of 235 ng/dL that would be expected according to calculations of patients’ ages. IGF-1 levels are age dependent.
Measures of RBC magnesium levels were also taken on the same day, and results as a group showed a mean magnesium level of 4.49 mg/dL, lower than the mean level in a control group of 12 osteoarthritic patients and the laboratory standard of 5.5 mg/dL.
“The findings suggest that if you determine that fibromyalgia patients have low magnesium levels, you might want to check IGF-1,” Dr Romano said.
He noted that in referring such patients to an endocrinologist, the results have been consistent.
“When I suspect a patient’s IGF-1 levels are low, I send them to an endocrinologist for confirmation and they will do the intravenous GHRH [growth hormone–releasing hormone]-arginine stimulation test,” he explained.
“The typical response is a peak and then the level comes down, but in the vast majority of fibromyalgia patients it’s just a flat reading, with no response.”
Treatment with growth hormone to restore normal levels typically starts with low dose, 0.2 mg, of subcutaneous injections daily for several months, with increased titration if levels are not restored within several months, Dr Romano said.
Although the study is small, Dr Romano urged clinicians to consider such factors when struggling with fibromyalgia management.
“The take-home message is to keep looking,” he said. “Fibromyalgia patients tend to have numerous comorbidities and they may be related.”
Studies that have also linked IGF-1 levels to fibromyalgia include a randomized, double-blind, placebo-controlled study published in 1997 in the American Journal of Medicine, which showed significant overall improvements in fibromyalgia symptom scores after IGF-1–deficient women were treated with daily growth hormone injections.
The “Future” of Chronic Pain
Pain specialist Forest Tennant, MD, PhD, from the Veract Intractable Pain Clinic in West Covina, California, who has also explored the role of hormones in chronic pain and presented a talk on the topic at the meeting, noted that, aside from the few earlier studies, the role of growth hormone in fibromyalgia has not been extensively explored.
“When it comes to pain, we’re not entirely certain what growth hormone does, but that it affects mainly hard tissue such as bone cartilage,” he told Medscape Medical News.
“But we’ve been extensively studying human chorionic gonadotropin and that looks like it works more importantly in the nervous system and really seems to be becoming an essential compound.”
“I’m glad they’re studying this, however, because [hormone involvement] is the future of chronic pain, there’s no question about it.”
Dr Romano has disclosed no relevant financial relationships. Dr Tennant receives speaker’s bureau fees from Ethos Labs, Regenesis Biomedical, and INSYS Therapeutics.
American Academy of Pain Management (AAPM) 2015 Annual Meeting. Presented September 19, 2015.