Dietary Inflammatory Index of mothers during pregnancy and ADHD symptoms in the child at preschool age: INMA and RHEA cohorts

摘要

Background: Attention deficit/hyperactivity disorder (ADHD) is the most frequent childhood-onset neuropsychia-tric condition, with an estimated worldwide prevalence of approximately 5% in school-aged children (Polanczyk et al, 2007). Pregnancy, infancy and childhood are critical periods of development, especially vulnerable to the effects of these risk factors (Tounian, 2011), and growing evidence suggests that exposure to adverse environmental and psychological conditions, especially when occurring in intrauterine life may increase the risk of developing ADHD in childhood (Buss et al, 2011). Previous studies have indicated that maternal dietary patterns during pregnancy are associated with cognitive and behavioural outcomes (Anjos et al, 2013). Given the pro-inflammatory potential of suspected nutrients, and evidence supporting a role of inflammation in the pathogenesis of ADHD, we hypothesise that a proinflammatory diet of the mother during pregnancy promotes the development of ADHD in the offspring. Validated dietary inflammatory indexes (DII) have been recently developed to capture the pro-inflammatory potential of diets based on known associations of specific food groups and nutrients with serum inflammatory markers (Cavicchia, 2009). The DII therefore offers a unique tool to assess the overall association of a maternal proinflammatory diet with child health outcomes; however this hypothesis has not been previously examined. Thus, the aim of this proposal is to evaluate the association between a validated DII of the mothers during pregnancy and ADHD symptoms in their children at the age of 4 years. Methods: The study population was 3,421 mother-child pairs from four INMA birth cohorts in Spanish regions of Gipuzkoa (N = 544), Sabadell (N = 694), Asturias (N = 589) and Valencia (N = 813) and the RHEA birth cohort in Greece (N = 781) recruited between 2004-2008. A validated (Shivappa, 2013) DII was calculated based on food frequency questionnaire information collected during pregnancy. ADHD symptoms were assessed by ADHD-DSM-IV (18 items) in INMA cohorts and by Attention-Deficit/Hyperactivity Disorder Test (ADHDT) (36 items) in RHEA cohort at around 4.5 years old of age, with questionnaires filled-out by teachers. Data on sociodemographic and anthropometric characteristics, diet, and lifestyle were collected through questionnaires. Association between maternal DII and ADHD symptoms of children was evaluated through negative binomial regression models stratified by cohort. Results: Statistically significant differences were observed in maternal DII depending on region (mean(sd)): Gipuzkoa (-1.64 (2.43)), Sabadell (-1.02(2.24)), Asturias (-1.76(2.40)) and Valencia (-1.01(2.44)) and RHEA cohort (2.36(2.01)). In preliminary pooled cohort analyses we found that maternal DII is not significantly associated with the risk of ADHD symptoms in children at 4 years of age. Subsequent analyses will evaluate differences in the association of interest according to region and other potential effect modifiers (eg, maternal overweight). Conclusions: Proinflammatory diets of the mother during pregnancy may have adverse effects on the health of the offspring that are yet not well understood. This study examines the association of a validated maternal DII with and the risk of ADHD symptoms in the offspring at 4 years of age in five birth cohorts with variable dietary patterns, and will provide novel insights for the role of maternal diet in the cognitive development of the child.