Foetal origin of adult diseases and contribution of David Barker. (Answer in 150 words)

- Foetal origin of adult diseases and contribution of David Barker. (Answer in 150 words)
Introduction
The foetal origins hypothesis holds that undernutrition in critical windows of gestation permanently programmes body structure and metabolism, setting adult risk of chronic disease.

Body
1. The hypothesis: a deprived foetus makes irreversible trade-offs — fewer nephrons, an altered stress axis, insulin resistance, reduced beta-cell mass — which Hales and Barker in 1992 called the thrifty phenotype. Disease follows when the predicted scarce environment fails to arrive, producing type 2 diabetes, hypertension and coronary disease.
2. Barker's evidence: he exploited the Hertfordshire ledgers, where a health visitor had recorded birthweight and weight at one year for fifteen thousand babies born from 1911, and linked them to death registers. This historical cohort showed coronary mortality rising steadily as birthweight fell.
3. Criticism and development: confounding by lifelong poverty and the crudeness of birthweight as a proxy were pressed against him. Corroboration came from the Dutch Hunger Winter cohort, where methylation differences persist, and from Yajnik's Pune study of the thin-fat Indian neonate.

Conclusion
It matured into the developmental origins of health and disease framework, central to explaining India's diabetes burden under rapid nutritional transition.