Developmental origins of health and disease: new insights.

Epidemiological and animal studies show that small changes in the developmental environment can induce phenotypic changes affecting an individual's responses to their later environment. These may alter the risk of chronic disease such as metabolic syndrome or cardiovascular disease. Recent research shows that animals exposed to such a mismatch between prenatal and postnatal environment develop obesity, reduced activity, leptin and insulin resistance, elevated blood pressure and vascular endothelial dysfunction. Epigenetic processes are involved in such effects, targeted to promoter regions of specific genes in specific tissues. Such fine control of gene expression suggests that the mechanisms have been retained through evolution through their adaptive advantage, rather than representing extreme effects of developmental disruption akin to teratogenesis. There may be adaptive advantage in a developmental cue inducing a phenotypic change in generations beyond the immediate pregnancy, and a range of data that support this concept. In animals, epigenetic effects such as DNA methylation can be passed to successive generations. Environmental toxins, including endocrine disruptors, may induce greater risk of chronic disease, even at low exposure levels, if they affect such normal developmental epigenetic processes. Appropriate interventions may have long-term multigenerational effects to reduce the risk of chronic disease.