Combination of low birth weight and high adult body mass index: at what age is it established and what are its determinants?

OBJECTIVE To investigate growth trajectories and predictive factors for those with low birth weight and high adult BMI. DESIGN Birth cohort study. SETTING England, Scotland, and Wales. PARTICIPANTS All born 3-9 March, 1958. MAIN OUTCOME MEASURES People at "high risk" of adult disease were defined as having a combination of lower birth weight (in the lowest third of the distribution) and high BMI (in the highest third of the distribution at age 33). RESULTS 284 of 3462 men and 338 of 3555 women were identified as "high risk". This group was shorter than other cohort members at age 7, on average by 1.2 cm (boys) and 1.8 cm (girls), with a deficit of about 3 cm in adult height. The "high risk" group had a similar mean weight to other subjects at age 7, but were heavier thereafter through to age 23. BMI was increased at all ages in the "high risk" group. Independent predictors include paternal BMI, maternal height and smoking in pregnancy, and social class. For each SD increase in father's BMI the odds of low birth weight/high BMI increased by about 20%. For maternal height, a 1 cm increase reduced the odds of low birth weight/high BMI by about 5%. Increased ORs for "high risk" were found for those with manual social origins (1.61 for men; 1.49 for women) and for maternal smoking in pregnancy (1.79 and 2.27 respectively). CONCLUSIONS Maternal short stature, low social class, and smoking during pregnancy influence the development of "high risk" for adult chronic disease. The causes of high risk therefore seem to reside in utero and even earlier, in the mother's lifetime, with adverse conditions having a detrimental affect and favourable conditions protecting against high risk.