Low birth weight and cardiovascular risk factors in Auckland adolescents: a retrospective cohort study

To determine whether birth weight is inversely associated with cardiovascular risk factors in a multiethnic sample of New Zealand adolescents.

A retrospective cohort with birth weight collected from hospital records of 855 (68%) out of 1260 Auckland-born students who had blood pressure, fasting blood lipids, and glucose measured while in Year 11-13 at high school.

After controlling for sex, age, and ethnicity, none of the following cardiovascular risk factors were associated with birth weight (p>0.05): systolic and diastolic blood pressure, total cholesterol, HDL cholesterol, triglycerides, and glucose. Serum cholesterol came closest to statistical significance: regression coefficient being--0.10 mmol/L (SE=0.06, p value=0.11). In contrast (after controlling for age, sex, and ethnicity), current Body Mass Index (BMI) was significantly (p<0.05) related to all above cardiovascular risk factors. The proportion of students with elevated serum cholesterol levels (top 20%) attributable to elevated BMI (>30 kg/m2) was 18%, and that attributable to low birth weight (<2.5 kg) was 2%.

These results do not support for the 'fetal origins' hypothesis. The very low proportion of adolescents with elevated coronary risk factors attributed to low birth weight suggests that the focus of cardiovascular disease prevention should remain in adolescence and adulthood, rather than in pregnancy.