Saw this story in The Globe and Mail, and I found the link for the original CMAJ Journal- It would appear that a trio of intrepid Canadian researchers have discovered the secret of Tintin's agelessness:
Acquired growth hormone deficiency and hypogonadotropic hypogonadism in a subject with repeated head trauma, or Tintin goes to the neurologist
We describe the unique case of a public figure who is well known for having delayed pubertal development and statural growth (Fig. 1). We believe we have discovered why Tintin, the young reporter whose stories were published between 1929 and 1975, never grew taller and never needed to shave.
Recent literature has helped us gain a better understanding of the pathophysiology of hypopituitarism resulting from repeated head trauma.3 We believe that the multiple traumas Tintin sustained could be the first case of traumatic pituitary injury described in the literature.
The authors with their subject