19 - The developmental environment and its role in the metabolic syndrome

Summary

Introduction

It has long been known that certain cardiovascular risk factors tend to cluster together in the same patients. The clustering of insulin resistance, glucose intolerance, dyslipidaemia and hypertension was originally described by Reaven (1988) and it has become evident in recent years that this clustering, now known as the metabolic syndrome, is among the most important causes of atherosclerotic vascular disease. Because of the increasing prevalence of obesity, which contributes strongly to this syndrome, the metabolic syndrome is likely to contribute markedly to the global burden of disease both in the developed and increasingly in the developing world. Despite its public-health importance, the aetiology is still poorly understood. In addition to obesity, a variety of other factors, both genetic and non-genetic, are involved, but at present these have remained poorly characterised. The demonstration over the past decade that several components of the metabolic syndrome have developmental origins offers new insights into understanding this important and common condition and may offer pointers to its prevention.

Developmental origins of the metabolic syndrome

Evidence that the metabolic syndrome might have a developmental origin came originally from a series of studies which show that several of the components of the syndrome are associated with small size at birth. In a study of 370 men born in Hertfordshire, UK, the prevalence of type 2 diabetes or glucose intolerance fell from 40% among men who weighed 5.5 lb (2.5 kg) or less at birth to 14% in those who weighed 9.5 lb (4.3 kg) or more (Hales et al. 1991).