# Aetiology

Aetiology

Epidemiological studies suggest that diverticular disease is a consequence of  a refined Western diet, deficient in dietary fibre. The combination of  altered collagen structure with ageing, disordered motility and increased intraluminal pres sure, most notably in the narrow sigmoid colon, results in herniation of  mucosa through the circular muscle at the points where blood vessels penetrate the bowel wall. The rectum has a complete muscular coat and a wider lumen and is thus v rarely a ff ected. Diverticular disease is rare in Africa and Asia, where the diet is high in natural fibre (Burkitt).