Small size at birth due to perturbations of growth and development in early life confers an increased risk of adverse health outcomes in adulthood such as obesity, cardiovascular and metabolic disorders (Breier et al. 2001). In addition, poor growth in early infancy, regardless of birth size, is associated with an additional risk of coronary artery disease, which is further confounded by rapid weight gain after 1 year of age (Eriksson et al. 2001). We are interested in the interaction between poor fetal development and adverse postnatal conditions, as mediated by undernutrition, on adiposity in later life. Body fat was therefore examined in young adult sheep whose mothers were exposed to moderate undernutrition (UN) in the immediate postconceptual period and who themselves faced a subsequent postnatal UN challenge.

Welsh Mountain ewes received either 100 % (ad libitum; group C, n = 38) or 50 % of global nutritional requirements (group U, n = 40) from conception to 30 days of gestation, and ad libitum thereafter. Offspring were fed either ad libitum (CC, n = 21 and UC, n = 19) or at an intake level that reduced body weight to 85 % of target weight (predicted from their individual growth trajectory, 0 -12 weeks) from weaning (12 weeks) to 25 weeks postnatal age and ad libitum thereafter (CU, n = 17 and UU, n = 21). Each group contained approximately equal numbers of males and females. Body weights were measured at birth, at 12 weeks of age and every week thereafter. At 17 months of age, back fat depth was measured by ultrasound and corrected for current body weight. Data (mean ± S.E.M.) were analysed by unpaired Student’s t test and linear regression.

In females, when considering all treatment groups together, increased fat depth at 17 months was predicted by poor growth rate during the postnatal UN challenge (12 -25 weeks; R² = – 0.15, P < 0.05) and high ‘catch-up’ growth after the challenge, as assessed by the fractional growth rate from 25 weeks to the time of fat measurement (kg gained/day/starting weight; R² = + 0.26, P < 0.005). Postnatal UN had no effect on mean fat depth in females that received control nutrition in the postconceptual period. However, corrected fat depth in females that received both pre-and postnatal UN challenges (UU; 0.16 ± 0.01) was significantly (P < 0.05) greater than those that were exposed to prenatal UN alone (CU; 0.12 ± 0.01). In males, fat depth tracked with current weight and was unaffected by UN treatment group.

These findings are the first in sheep to show that, in common with observations in humans, a combination of poor growth in early postnatal life followed by a high subsequent growth rate is associated with increased adult fat deposition. In addition, the predisposition to increase body fat following perturbed prenatal nutrition may not be revealed until well after a subsequent period of UN in early postnatal life when nutrition is restored to ‘normal’. These effects were only observed in females. The long-term effects of altered patterns of early life growth on the changes in body fatness with age, and on metabolic and cardiovascular homeostasis, remain to be determined.

This work was supported by British Heart Foundation.