Background: The relationship between birth weight and plasma lipoproteins is inconsistent.
Aims: To assess the association between birth weight and (1) body mass index (BMI) at birth and (2) lipoproteins in young adults, and also to explore the possible effect of current obesity as a possible effect modifier.
Methods: Two prospective studies based on representative samples of subjects born in the 1970s were carried out in Ribeirão Preto, Brazil (n=2063) and Limache, Chile (n=999). The surveys were carried out between 2001 and 2004.
Results: Mean birth weights were 3267 g and 3177 g and mean adult BMIs were 24.3 kg/m2 and 25.8 kg/m2 in the Brazilian and Chilean samples, respectively. Total adult cholesterol was 4.57 mmol/l in Chileans, 0.26 mmol/l higher than in Brazilians (p<0.001). The main finding was an interaction between adult obesity (BMI 30 or over) and birth weight and also BMI at birth and low-density lipoprotein (LDL) and total cholesterol. A birth-weight increment of 1 kg was associated with a decrease in total cholesterol (-0.374 mmol/l, 95% CI -0.567 to -0.181) and LDL (-0.304 mmol/l (-0.479 to -0.129) in obese participants only. These associations persisted after allowing for gestational age in a smaller sample. This finding was consistent in separate analyses in the Brazilian and Chilean samples. No associations were found in relation to high-density lipoprotein and triglyceride concentrations.
Conclusion: The results suggest that those who were of low birth weight and are obese are more likely to have high cholesterol and LDL concentrations. Thus preventing obesity may be especially rewarding in subjects with a low birth weight.