Endocrine Abstracts

Introduction: The adipokine adiponectin promotes insulin sensitivity and its circulating levels are inversely related to adiposity in adults and older children. In small for gestational age (SGA) infants adiponectin levels decline rapidly with age in early life and have been inversely associated with subsequent weight gain. There are few data in early infancy, especially in non-SGA infants.

We therefore investigated the association between adiponectin levels and growth in early infancy in a general population-based birth cohort.

Method: The Cambridge Baby Growth Study (CBGS) collected detailed infant anthropometry and capillary dried blood spots (DBS) from birth to 2 years. DBS collected at 3 months, and a small pilot subgroup at 12 months, were processed using an adiponectin serum DELFIA immunoassay, adapted for DBS.

Results: Mean (S.D.) adiponectin levels at 3 months in 306 infants (142 males) non-SGA infants (13.2±4.8 (4.1–28.2) μg/ml) were much higher than at 12 months (n=63) 4.4±1.6 (1.5–9.0) μg/ml.

Three-month adiponectin levels were inversely related to age (B −0.1, P<0.0005), and were higher in exclusively breast fed vs other infants (P=0.01). Adiponectin levels at 3 months were strongly inversely related to birth and 3 month length, weight, and skinfold thicknesses. In multivariate models the strongest correlates with 3 month adiponectin levels were length and infancy age. Additionally, adiponectin was positively associated with 3 month DBS levels of branched chain amino acids.

Conclusions: Circulating adiponectin levels can be quantified in DBS using immunoassay. Three month adiponectin levels were inversely correlated with infancy length, which is a novel finding. Higher levels of branched chain amino acids associated with higher adiponectin levels may indicate decreased insulin secretion. We hypothese that reduced insulin secretion in infants with short length results in higher adiponectin levels, and consequently increased insulin sensitivity, allowing some (though incomplete) compensation for hypoinsulinaemia.