Low birth weight predicts elevated plasma cortisol concentrations in adults from 3 populations

Low birth weight is linked with raised blood pressure in adult life. Recent evidence has suggested that a neuroendocrine disturbance involving the hyp othalamic-pituitary-adrenal axis could mediate this link. We therefore inve stigated the relation between birth weight and fasting plasma cortisol conc entrations and the association of cortisol with current blood pressure in p opulation samples of 165 men and women born in Adelaide, South Australia, f rom 1975 to 1976, 199 men and women born in Preston, UK, from 1935 to 1943, and 306 women born in East Hertfordshire, UK, from 1923 to 1930. Fasting p lasma cortisol was measured in plasma samples obtained between 8 and 10 AM. Blood pressure was measured with an automated sphygmomanometer. Low birth weight was associated with raised fasting plasma cortisol concentrations in all 3 populations. A combined analysis that allowed for differences in the gender composition, age, and body mass index between the studies showed th at cortisol concentrations fell by 23.9 nmol/L per kilogram increase in bir th weight (95% CI 9.6 to 38.2, P<0.001). Fasting plasma cortisol concentrat ions also correlated positively with the subjects' current blood pressure. However, the association between cortisol and blood pressure was most marke d in subjects who were obese (P=0.038 for interaction between body mass ind ex and cortisol, P=0.01 for interaction between waist-to-hip ratio and cort isol), These results show that low birth weight is associated with raised f asting plasma cortisol concentrations. Increased activity of the hypothalam ic-pituitary-adrenal axis may link low birth weight with raised blued press ure in adult life.