Could a nonfunctional adrenal incidentaloma be a risk factor for increased carotid intima-media thickness and metabolic syndrome.

BACKGROUND

This study was designed to detect the potential association of a nonfunctional adrenal incidentaloma (NFAI) with insulin resistance and associated metabolic disturbances, with a subsequent increase in cardiovascular risk factors.

METHODS

Eighty-three NFAI patients and 56 volunteers (controls) without any adrenal abnormalities on computed tomography (CT) were included. Fasting blood glucose (FBG), fasting insulin, lipid profiles, uric acid, homocysteine, fibrinogen, high sensitivity C-reactive protein (hs-CRP), and adiponectin levels were measured in both groups. Blood pressure (BP), waist circumference, body mass index (BMI), and carotid intima media thickness (CIMT) were evaluated in both the patients and volunteers.

RESULTS

There were no significant difference between the NFAI and control groups with respect to age, sex, BMI, waist circumference, systolic and diastolic BP, smoking, concomitant disease, and medications. Fasting insulin and glucose levels and homeostasis model of assessment-insulin resistance (HOMA-IR) scores were significantly higher in the NFAI group as compared with those in the control group (p<0.01). The frequency of metabolic syndrome in the NFAI group was higher than that in the control group (p<0.01). All the lipid fractions, except triglyceride (TG), (p<0.05), homocysteine (p=0.01), and fibrinogen levels (p<0.001), were significantly higher in the NFAI group as compared with the levels in the control group. There were no significant differences between the NFAI and control groups in terms of uric acid, hs-CRP, and adiponectin levels. The CIMT values in the NFAI group were significantly higher than those in the control group (0.74±0.14 vs. 0.53±0.09, p<0.001). The mean CIMT value showed a statistically positive correlation with age (r=0.245, p=0.004); the HOMA-IR score (r=0.490, p<0.001); and FBG (r=0.521, p<0.001), fasting insulin (r=0.432, p<0.001), total cholesterol (TC) (r=0.267, p=0.002), and fibrinogen (r=0.398, p<0.001) levels in the NFAI group.

CONCLUSIONS

The results indicated that the NFAI patients had an elevated risk of insulin resistance, with metabolic syndrome and increased CIMT values. Long-term follow-up studies should be designed to evaluate postsurgical alterations in metabolic parameters and cardiovascular risk factors in NFAI patients.