AUTISM SCIENCE IN THE NEWS: OBESITY IN AUTISM SPECTRUM DISORDER

PATERNAL OBESITY AND INCREASED RISK FOR AUTISM IN OFFSPRING

Another incentive for managing weight when planning for family?

By Lirio Sobrevinas-Covey, Ph.D.

Obesity – having a basal metabolism index (BMI) over 30 was implicated as a risk factor for autism spectrum disorder (ASD) in children in a recent well controlled study conducted in Norway. (BMI is calculated by dividing weight in kilograms by height in meters squared).

The study used the DSM-IV typology of autism. Paternal obesity was associated with autistic disorder and Asperger’s syndrome, but not with pervasive developmental disorder.

Obesity in fathers, not in mothers, significantly increased risk of autism in children. This finding had been unexpected since a prior research had implicated mothers’ obesity as an autism risk factor. (1) That study, however, did not include fathers’ obesity among the variables to be examined.

In this study by Suren and colleagues (2), whereas mothers’ obesity had appeared to be a risk factor when assessed by itself, once both mothers’ and fathers’ obesity were considered simultaneously, it was only fathers’ obesity that showed statistical independence. The significant effect of paternal obesity and lack of effect of maternal obesity remained after controlling for potential modifiers of the association: parental age, parental smoking, parental education, parental psychiatric history, as well as the children’s year of birth, and the number of mother’s children. (Prior research has also implicated increased father’s and mother’s age as autism risk factors).

This study had several strengths including – its longitudinal design (children were followed from 4-13 years after first screening), recency (children born from 1999 to 2009 and processed by December, 2012), use of a large sample (92,909 children from a population-based mother and child cohort study), careful measurement of the Autism diagnoses following DSM-IV criteria, and estimation of odds ratios and 95% confidence intervals from logistic regression models.

Knowledge of risk factors can lead to understanding of the underlying etiology and mechanisms, all essential to effective prevention. Knowledge of maternal risk factors can give rise to hypotheses regarding intrauterine exposures. Evidence regarding paternal influences suggests the additional importance of investigating for genetic and epigenetic risk factors of autism.

References:

(1) Krakowiak P, Walker CK, Bremmer AA et al, Maternal metabolic conditions and risk for autism and other neurodevelopmental disorders. Pediatrics. 2012; 129 (5).

(2) Suren P, Gunnes N, Roth C, et al. Parental Obesity and Risk of Autism Spectrum Disorder. Pediatrics 2014; 133:e1128-e1138.