medwireNews: Postmenopausal women with asthma have significantly higher rates of insulin resistance than those without the condition, research shows.
Levels of leptin were also higher in these women, while adiponectin was lower, report the researchers, who say that a tendency toward hyperglycemia and insulin resistance may play a role in the development of asthma and allergies.
"Insulin resistance could be the possible link between asthma and inflammatory mechanisms," propose Murat Aydin (Namik Kemal University, Merkez-Tekirdag, Turkey) and colleagues.
In their study, fasting insulin levels were significantly higher among the 45 postmenopausal women with asthma compared with the 30 women without at 12.7 µIU/mL versus 7.1 µIU/mL. And, insulin resistance, according to the homeostasis model assessment, was significantly more common in women with asthma, at 5.3% compared with 2.1%.
However, rates of the metabolic syndrome were 26.7% in each group and rates of Type 1 diabetes were comparable at 24.4% and 20.0%, respectively.
And, while there was no association between asthma and obesity, leptin levels were significantly higher in women with asthma compared with control women, at 50.4 ng/mL versus 26.5 ng/mL, whereas adiponectin levels were significantly lower at 31.5 ng/mL versus 35.4 ng/mL. Additionally, levels of tumor necrosis factor (TNF)-α were significantly higher in asthma patients, and interleukin(IL)-8 levels were also raised, although not significantly.
"Higher leptin, IL-8, TNF-α, and lower adiponectin levels in [the] asthma group might lead to dysregulation in adipose tissue in asthma patients," suggest the authors, writing in Inflammation.
They note that a previous study found leptin to be a predictive factor in the development of asthma, and that animal studies suggest adiponectin may be protective in airway disease. However, results are conflicting, they say.
"Further studies are needed to elucidate the interaction between insulin resistance and asthma severity from different age groups with different body mass index," the authors conclude.
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