The influence of age on the GH-IGF1 axis in patients with acromegaly

The purpose of this study was to investigate the influence of age on GH and IGF1 axis, and complications in patients with acromegaly.

From the medical records, we retrospectively analyzed clinical features and complications in 87 newly diagnosed patients with active acromegaly (34 males, 53 females; aged 18-82 years) who were admitted to Tokyo Women's Medical University between 1999 and 2006. We divided the patients into three groups according to age: or=61 years old (elderly group).

The median GH levels in young, middle-aged, and elderly groups were 18.5, 8.8, and 6.7 microg/l respectively, and the IGF1 levels were 810, 717, and 740 microg/l respectively. The values were not significantly different among the groups. However, the serum IGF1 SDS were significantly higher in the elderly group (10.2) than those in young and middle-aged groups (6.6 and 6.2 respectively, P<0.001). The age difference in the higher IGF1 SDS was remarkable in female patients. In the elderly group, glucose intolerance and hypertension were found in 94 and 53% of the patients respectively and the incidences were higher than those in the other groups.

This study suggests that the relatively high IGF1 secretions in elderly patients might be involved in the progression of clinical complications in acromegalic patients. Therefore, awareness of the early symptoms and examination of serum GH and IGF1 are important for patients with acromegaly.