Decreasing birth weight is associated with adverse metabolic profile and lower stature in childhood and adolescence

OBJECTIVE We aimed to evaluate the association of birth weight SDS with insulin resistance, blood pressure, and auxology in children and adolescents born 23-42 weeks of gestation. METHODS We studied 143 singleton children and adolescents aged 9.3 ± 3.3 years (range 2.0-17.9 years). Clinical assessments included insulin resistance measured by HOMA2-IR, auxology, and blood pressure from sphygmomanometer measurements. Continuous associations were examined, and stratified analyses carried out. For the latter, participants were divided into those of below-average birth weight (BABW, <0 SDS) and above-average birth weight (AABW, ≥0 SDS). RESULTS Irrespective of gestational age, lower birth weight SDS was associated with progressively greater HOMA2-IR (p<0.0001) and higher fasting insulin concentrations (p<0.0001). Decreasing birth weight SDS was associated with higher systolic (p = 0.011) and diastolic (p = 0.006) blood pressure. Lower birth weight SDS was also associated with decreasing stature (p<0.010). The BABW group was ~40% more insulin resistant than AABW participants (p = 0.004), with the former also displaying fasting insulin concentrations 37% higher (p = 0.004). BABW participants were 0.54 SDS shorter than those of higher birth weight (p = 0.002). On average, BABW participants had not met their genetic potential, tending to be shorter than their parents (p = 0.065). As a result, when corrected for parents' heights, BABW participants were 0.62 SDS shorter than those born of higher birth weight (p = 0.001). Sub-group analyses on participants born appropriate-for-gestational-age (n = 128) showed that associations of birth weight SDS with both insulin resistance and stature remained (although attenuated). CONCLUSION Decreasing birth weight SDS (even within the normal range) is associated with adverse metabolic profile and lower stature in children and adolescents.