Impaired head circumference growth and behavioural problems in childhood: Longitudinal findings from the MINA‐Brazil birth cohort.

Background Objective Methods Results Conclusions Previous evidence on the relation between early head circumference (HC) growth and behavioural outcomes in preschoolers has been inconsistent.We aimed to investigate whether HC growth from birth to 5 years of age was related to internalising or externalising behavioural problems at 5 years of age in a sex‐specific manner.Among 303 girls and 318 boys from the MINA‐Brazil birth cohort, we examined the associations between changes in HC from birth to 5 years of age and internalising and externalising behaviour problem scores at 5 years according to the Strengths and Difficulties Questionnaire for parents. HC values were transformed into sex‐ and age‐specific z‐scores (HCZ) using World Health Organisation standards, and the differences between values at 5 years of age and birth were classified into quintiles. We estimated adjusted mean differences with 95% confidence intervals in behavioural problem scores between HCZ change quintiles using multivariable linear regression by sex. To examine nonlinear associations, we included cubic spline terms.Head circumference growth from birth to 5 years of age was inversely and nonlinearly associated with internalising problems in girls. Compared with girls at the lowest quintile of HC growth, those above had an adjusted 1.27 (95% confidence interval 0.28, 2.27) points lower mean internalising problems score. This association was mostly driven by HC growth during the first 2 years. We found no association between HC growth and externalising behaviour in either sex.Impaired HC growth was related to higher mean internalising problem scores at 5 years of age in girls but not in boys. HC growth was not associated with externalising problems. [ABSTRACT FROM AUTHOR]