Researchers reported that daily maternal intake of sweetened carbonated beverages (SCB) in pregnancy was associated with ADHD symptoms in children at eight years of age.
The magnitude of associated in the study was weak (typically 15-21% increased relative risk of finding six or more ADHD symptoms in children), suggesting that SCB only played a minor role in the aetiology of ADHD. However, further research into causal agents is warranted, as SCB are common exposures; the researchers noted that a small reduction of risk may still be of importance for ADHD symptoms in children at the population level.
Norwegian, Swedish, and Dutch researchers examined a large Norwegian population-based cohort recently reported in the European Journal of Nutrition to understand the impact of drinking SCB during pregnancy on offspring.
National MoBa-study
The study was based on data from the Norwegian Mother, Father and Child Cohort Study (MoBa) and the Medical Birth Registry of Norway (MBRN). MoBa is a large prospective population-based pregnancy cohort study conducted by the Norwegian Institute of Public Health. Participants were recruited from across Norway from 1999 to 2008. The women consented to participation in 41% of the invited pregnancies. Participating women answered three questionnaires during pregnancy, of which the second was a food frequency questionnaire, introduced in 2002 and completed during mid-pregnancy.
After delivery, questionnaires were sent to the family when the child was six months, 18 months, and at three, five, seven and eight years old, with additional questionnaires when the child was a teenager. The cohort now includes 114,500 children, 95,200 mothers and 75,200 fathers. For the MoBa pregnancies, data was routinely linked to the MBRN, based on mandatory reporting of information on pregnancies and birth outcomes for all births in Norway since 1967.
The study population consisted of 39,870 mother-child pairs of mothers who responded to the food frequency questionnaire and a questionnaire when their child was eight years old. The exposure was defined as maternal intake (daily servings) of SCB (sugar and artificially sweetened), using no daily intake as reference. The study uncovered that ADHD symptoms in children were evaluated as a continuous standardised ADHD score and as a binary outcome of six or more ADHD symptoms versus five symptoms or less.
More research is needed
Associate professor Liv Grimstvedt Kvalvik at the University of Bergen is the first author of the study. She explained that the authors adjusted for possible factors that may explain the associations of ADHD symptoms in children. Factors such as maternal educational level, maternal pre-pregnancy body mass index, maternal depression and anxiety, maternal ADHD symptoms, other components of the maternal diet, maternal age at delivery, parity, birth year and season.
The study was an observational study and conclusions about causality cannot be drawn with certainty, and residual confounding by lifestyle factors or medical conditions not accounted for may be present. However, the longitudinal design with prospectively collected data strengthens the results and their interpretation. Whilst this study suggested that daily maternal intake of SCBs could be linked to a small increase in ADHD symptoms in children at eight years of age, further research is needed to explore this association.
