Socioeconomic position in young adulthood is associated with BMI in Australian families

BACKGROUND: Low socioeconomic position (SEP) is associated with increased cardiovascular (CV) disease risk, but the relative importance of SEP in childhood and adulthood, and of changes in SEP between these two life stages, remains unclear. Studies of families may help clarify these issues. We aimed to assess whether SEP in young adulthood, or change in SEP from childhood to young adulthood, was associated with five continuously measured CV risk factors. METHODS: We used data from 286 adult Australian families from the Victorian Family Heart Study (VFHS), in which some offspring have left home (n = 364) and some remained at home (n = 199). SEP (defined as the Index of Relative Socioeconomic Disadvantage) was matched to addresses. We fitted variance components models to test whether young adult SEP and/or change in SEP was associated with systolic blood pressure, diastolic blood pressure, body mass index (BMI), total cholesterol or high-density lipoprotein cholesterol, after adjustment for parental SEP and within-family correlation. RESULTS: An increase in SEP of 100 SEIFA units from childhood to adulthood was associated with a lower BMI (β = -0.49 kg/m(2), P < 0.01) only. CONCLUSIONS: These results suggest that a change in SEP in young adulthood is an important predictor of BMI, independent of childhood SEP.