Obesity may independently increase cognitive decline, CV autonomic neuropathy risk
Adults with severe obesity may be at higher risk for cognitive decline and cardiovascular autonomic neuropathy than those with normal weight, and this risk may be amplified by greater waist circumference, according to findings published in Diabetes Care.
“Obesity, and particularly central obesity, is more important for nerve related injuries — cognitive deficits, peripheral neuropathy and autonomic neuropathy — than for retinopathy and nephropathy,” Brian C. Callaghan, MD, MS, associate professor of neurology at the University of Michigan, told Healio. “Understanding the risk factors for different complications can lead to new interventions to prevent them.”
Callaghan and colleagues compared the prevalence of retinopathy, CV autonomic neuropathy, cognitive deficits and nephropathy among 33 adults with BMI greater than 35 kg/m2 or severe obesity and normoglycemia (mean age, 40.2 years; 75.8% women), 56 adults with severe obesity and prediabetes (mean age, 44.7 years; 82.1% women), 49 adults with severe obesity and diabetes (mean age, 48.9 years; 69.4% women) and 46 adults without obesity (mean age, 44.1 years; 82.6% women), whom the researchers identified as “lean.”
The researchers used NIH Toolbox cognitive scores to evaluate cognitive function, expiration-to-inspiration ratio to identify CV autonomic neuropathy, nonmydriatic retinal photographs to identify retinopathy, estimated glomerular filtration rate to identify nephropathy and distal leg nerve fiber density to identify peripheral neuropathy.
The researchers found that 25.6% of those with severe obesity and diabetes, 22.2% of those with severe obesity and normoglycemia, 17.7% of those with severe obesity and prediabetes and 6.5% of those without obesity had cognitive deficits. In addition, the average NIH Toolbox composite score was –0.1 for those with severe obesity and normoglycemia and 0.4 for those without obesity (P = .04), according to the researchers, who noted that the composite scores had negative associations with waist circumference and abdominal circumference.
The researchers further observed that 31.9% of those with severe obesity and diabetes, 21.4% of those with severe obesity and prediabetes, 18.2% of those with severe obesity and normoglycemia and 4.4% of those without obesity had CV autonomic neuropathy. According to the researchers, expiration-to-inspiration ratio, which was used to identify CV autonomic neuropathy, had a negative association with waist circumference.
“Taken together, our results indicate that central obesity is much more important than general obesity,” the researchers wrote. “Interventions that shift adipose storage preferentially to noncentral locations may help reduce many different complications of obesity.”
Only those with severe obesity and prediabetes (1.9%) and severe obesity and diabetes (6.1%) had retinopathy, and there was a negative association between prediabetes and retinal function, according to the researchers, who also found that 16.3% of those with severe obesity and diabetes, 17.9% of those with severe obesity and prediabetes, 6.1% of those with severe obesity and normoglycemia and 6.5% of those without obesity had nephropathy.
“In addition to hyperglycemia, physicians should likely focus on obesity treatments to prevent complications such as cognitive deficits, peripheral neuropathy, and autonomic neuropathy,” Callaghan said. – by Phil Neuffer
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Brian C. Callaghan, MD, MS, can be reached at firstname.lastname@example.org.
Disclosures: Callaghan reports he has consulted for DynaMed, the Immune Tolerance Network, a Patient-Centered Outcomes Research Institute grant and the Vaccine Injury Compensation Program. Please see the study for all other authors’ relevant financial disclosures.