The negative impact of obesity upon children’s physical and psychological health has been established as an issue of concern in countries around the world. Studies also have shown that childhood intelligence is inversely related to negative health outcomes later in life.
In exploring those two concepts, a new study aims to expand current understanding of the relationship between children’s body mass index (BMI) and cognitive ability (IQ) by considering the effects of 13 socioeconomic factors, including parents’ educational levels, breastfeeding, family financial security and others.
Amir Alishahi Tabriz, MD, MPH, doctoral student in health policy and management at the UNC Gillings School of Global Public Health, is lead author of the research, published online Aug. 10 in the journal Nature—Nutrition and Diabetes.
Alishahi Tabriz and colleagues examined data on 1,151 preschool children in both rural and urban areas of Iran who were ages six or seven in the years between 2009 and 2013.
Study analysis found that the children’s IQ, as determined by the Wechsler Intelligence Scale for Children administered as part of the study, was associated with household income, place of residence, type of delivery at birth (natural or Caesarean), type of infant feeding and parents’ education levels.
Living in metropolitan and urban areas and the level of the children’s fathers’ education was positively related to IQ, and BMI was negatively related to IQ test results. The BMI-IQ relationship appeared to be largely mediated, however, when socioeconomic factors were taken into account.
The authors found that children who were breastfed, who were from wealthier and/or smaller families and who lived in urban areas had higher IQ scores. This primarily occurred because of multicollinearity between parents’ education and other socioeconomic factors, such as place of residence and wealth. No difference in IQ scores was observed based upon gender, ethnicity or parents’ ages.
Of particular interest was the authors’ call for a health-care system that reflected a “multifaceted national policy.” Owing to rapid lifestyle changes in Iran, where some families still regard overweight children as a sign of health and prosperity, the authors refer to the “double burden of nutritional disorders among young children” – i.e., both underweight and overweight children – and note the need to implement preventive nutritional programs for preschoolers.
Dr. Nazanin Kiapour, in the UNC School of Medicine’s Department of Microbiology and Immunology is a study co-author. Other co-authors are Dr. Mohammad-Reza Sohrabi, Dr. Sousan Parsay, Dr. Alireza Abadi and Fahimeh Ahmadi, of the Shaid Beheshti University of Medical Sciences in Tehran, Iran; Dr. Mounes Aliyari, of The Johns Hopkins University School of Medicine; and Dr. Alireza Roodaki, of the Supélec, Gif-sur-Yvettte, in Paris.