Source: Liver  |  Posted 9 years ago

The relationship between size at birth and cortisol concentrations in adult life differs according to gestational age.

Both hypercortisolism and hypocortisolism might arise as a result of foetal programming of the hypothalamic-pituitary-adrenal axis during intrauterine life, say researchers in Helsinki, Finland.

They reported these conclusions after examining the relationship between adult hypothalamic-pituitary-adrenal axis function and birth weight and body proportions at birth in 421 men and women aged 65.1-75.8 (mean 69.5) years. These people were born at term and had body size and gestational age at birth recorded.

The researchers based their work on recent studies which suggested that lifelong programming of the hypothalamic-pituitary-adrenal axis in utero did much to explain the link between small size at birth and adult cardiovascular disease.

But, as direct evidence from human birth cohorts had been contradictory, the researchers sought to find out why.

They measured the ratio between fasting serum cortisol and cortisol-binding globulin concentrations to estimate the concentration of free cortisol.

No significant correlation was found between fasting cortisol concentrations and birth weight in either men or women. There was, however, a weak inverse association in women, though not in men, between fasting cortisol and length at birth. There was also a significant positive association between cortisol and ponderal index in both sexes.

The researchers found that the association between foetal growth on fasting total and free cortisol concentrations differed in patients born at different gestational ages.

In those born before 39 weeks of gestation, both total and free cortisol showed significant inverse correlations with birth weight and length at birth. In those born after 40 weeks of gestation, there were significant positive correlations with birth weight and ponderal index at birth.

Interactions between birth weight and gestational age were statistically significant.