IGF-1 as a possible marker of early cognitive impairment: A pilot study

Insulin-like growth factor (IGF)-1 is an important neurotrophic hormone. Disregulation of this hormone has been reported to influence the genesis of cognitive impairment and dementia in the elderly patients. We evaluated IGF-1 serum values and cognitive status in elder subjects. Primary endpoint was finding a possible link between IGF-1 values and MMSE scores, adjusted for age and sex. Elder patients (range 55–71 ys) were followed for up to 4 years (median 3.2 years). Cognitive status was assessed by Mini Mental State Examination (MMSE). A total of 210 subjects were enrolled. Yearly evaluation included routine laboratory tests, a complete physical examination and cognitive state measurement. At baseline evaluation, patients were divided into three groups: Healthy (MMSE > 26), Borderline (MMSE 24–26), Cognitive impairment (MMSE < 24). We used multiple linear regression with a scatter plot to compare IGF-1 and MMSE, adjusted for diagnosis of hypertension. Then, we checked the ROC curve, analyzing the AUC of our marker. At the baseline evaluation, no differences were found in the three groups for therapy and other diseases. Borderline subjects differed from other two groups, with a significant elevation of IGF-1 values (P < 0.05). The AUC curve of the yearly evaluation showed significant values (0.86 ± 0,02). This trial showed IGF-1 elevation in borderline subjects. Further studies will be performed in order to demonstrate the efficacy and sensibility of this serum marker.