medwireNews: Low levels of insulin-like growth factor (IGF)1 are associated with increased rates of cardiovascular (CV) events among women with rheumatoid arthritis (RA), researchers report.
The longitudinal study included 184 female RA patients aged an average of 52 years, who were categorized according to whether their serum IGF1 levels were below the median level of 140 ng/mL (low IGF1 group), or at or above this threshold (high IGF1 group). Median IGF1 levels in the low and high groups were 109.5 ng/mL and 182.5 ng/mL, respectively.
Malin Erlandsson (University of Gothenburg, Sweden) and colleagues found that the 10-year risk for experiencing CV events, estimated using a digital version of the Framingham algorithm, was significantly higher among patients with low versus high IGF1 levels, at rates of 7.0% versus 3.2%.
Moreover, there was a “strong negative relation” between IGF1 levels at baseline and self-reported new CV events at a telephone interview held 5 years later, with patients in the low IGF1 group having an approximately 5-fold higher CV risk than those in the low IGF group on Mantel–Cox analysis.
Erlandsson et al say that low IGF1 levels were associated with a number of traditional CV risk factors, most notably hypertension. They stress that there was a “remarkable increase” in the use of treatment for hypertension between baseline and the 5-year follow-up among patients with low IGF1 levels, but not among those in the high IGF1 group.
Taken together with previous evidence supporting “a direct causality between low IGF1 and hypertension,” these findings suggest that “[l]ow serum IGF1 precedes and predicts the development of early CV [disease] events due to a tight connection with hypertension, which is important for future management of RA patients,” write the researchers in BMC Medicine.
They also note that the IGF1-associated increase in CV risk was “most noticeable” in women aged less than 50 years, indicating that “vascular effects related to IGF1 may precede severe atherosclerotic change in the vessel wall and predispose to its early development.”
While this is “the largest study of the relation between IGF1 levels and cardiovascular morbidity in RA,” the study authors caution that their findings may not be generalizable to male RA patients.
Discussing the practical implications of their study, they say that physical inactivity “is frequently associated with lower serum IGF1,” and lifestyle interventions to increase physical activity and increase IGF1 levels “could be an attractive [option] for RA patients.”
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