Is the association between dietary patterns and cognition mediated by children's adiposity? A longitudinal approach in Generation XXI birth cohort

Abstract

Background/aims: There is a consistent body of evidence on the association between single nutrients and cognition, but the role of a healthful dietary pattern on cognition in children has been seldomly studied. This study aims to assess the association between dietary patterns at 4 years (y) and cognitive abilities at 10-13y and examine whether adiposity mediated these associations. Methods: This study used data from a sub-sample of the population-based birth cohort Generation XXI, with complete information on diet and cognition (n = 3575). At 4y, data on dietary intake was collected by a validated food frequency questionnaire and dietary patterns were derived by latent class analysis, namely Energy-dense food (EDF) pattern, Snacking pattern and Healthier pattern (Reference). At 1013y, the Portuguese Version of the Wechsler Intelligence Scale for Children®-Third Edition was administered by trained psychologists and age-adjusted composite scores were computed: a Full-Scale Intelligence Quotient (IQ), plus a Verbal IQ, Performance IQ and Processing Speed IQ. Age- and sex-specific body mass index (BMI) z-scores, body fat percentage from bioimpedance, and waist-to-weight ratio and waist-to-hip ratio were used as measures of adiposity. Regression coefficients and 95% confidence intervals (CI) were computed using linear regression models (adjusted for maternal age and education, pre-pregnancy BMI, smoking and alcohol intake during pregnancy, child's sex, birthweight, exclusive breastfeeding duration and having siblings at 4y). Mediation analysis was conducted using path analysis. Results: After adjustment, children classified in the EDF or a Snacking patterns at 4y were more likely to have lower scores on total IQ (ß = 0.116; 95%CI:0.192,0.039 and ß = 0.148; 95%CI 0.252,0.044, respectively), Verbal IQ (ß = 0.104; 95%CI 0.177, 0.031 and ß = 0.163; 95%CI 0.262,0.064, respectively) and Performance IQ (ß = 0.116 95%CI 0.193,0.040 and ß = 0.147; 95%CI 0.250,0.042, respectively) at 1013y, when compared to those classified in the Healthier pattern. None of the adiposity measures seemed to explain the associations between dietary patterns and IQ. Conclusion: This study supports that early unhealthy dietary patterns were associated with lower child's cognitive ability, but this effect did not seem to be mediated by adiposity.