Birthweight and behavioural problems in children: a modifiable effect?

BACKGROUND Low birthweight has been shown to predict behavioural problems in children. Less is known about the effect of birthweight, and how this may interact with the social environment in determining behaviour in a general population sample. We have examined the relationship between birthweight and social factors on childhood psychological well-being. METHODS Cross-sectional analysis of data on 5181 children aged 4-15 years from a randomly selected household population, the 1997 Health Survey for England. The main outcome measures were behavioural problems as defined by the Strengths and Difficulties Questionnaire (SDQ) in relation to birthweight and social environmental factors. RESULTS Birthweight was a significant predictor of total difficulties score (odds ratio [OR] = 1.27, 95% CI : 1.07, 1.49), hyperactivity in boys (OR = 1.25, 95% CI : 1.05, 1.51), and peer problems in girls (OR = 1.24, 95% CI : 0.99, 1.53). There was a strong social class gradient in the prevalence of behavioural problems for all birthweight tertiles. Bivariate analysis showed that high total difficulties score was significantly more common in lower birthweight tertiles for social classes III non-manual and III manual (P:-value for trend 0.05 and 0.03, respectively). There were smaller, non-significant effects of birthweight on the prevalence of behavioural problems in social class I and II, and IV and V. Statistical tests for an interaction between birthweight and social class were not significant. CONCLUSIONS Early life factors, such as birthweight and social class have important influences on psychological well-being in children. The birthweight effect is influenced by social factors, with the possibility that an advantaged social environment protects against the development of behavioural problems, and a disadvantaged environment increases the risk of behavioural problems, regardless of birthweight.