19007
Digit Ratio and Autism Spectrum Disorders: Results from the Avon Longitudinal Study of Parents and Children (ALSPAC) Birth Cohort

Saturday, May 16, 2015: 11:30 AM-1:30 PM
Imperial Ballroom (Grand America Hotel)
A. L. Guyatt1, J. Heron1, B. Knight1, J. Golding1 and D. Rai2, (1)School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom, (2)Avon and Wiltshire Partnership NHS Mental Health Trust, Bristol, United Kingdom
Background: Autism spectrum disorders (ASDs) are complex neurodevelopmental disorders with a preponderance amongst males. The extreme male brain (EMB) theory of autism suggests that increased fetal testosterone exposure may predispose to an exaggerated male cognitive profile. Second-to-fourth digit ratio (2D:4D), a sexually dimorphic trait, is used as a fetal testosterone proxy: lower, masculinized 2D:4D may imply increased exposure.

Objectives:  We sought to investigate the association between 2D:4D and ASD, including ASD traits, in the Avon Longitudinal Study of Parents and Children (ALSPAC), a UK-based population study.

Methods: 6015 children were studied (including 56 with ASD). Using logistic regression, we examined for association of 2D:4D with ASDs and four dichotomized ASD traits: the Children’s Communication Checklist (coherence subscale), the Social and Communication Disorders Checklist, a measure of repetitive behavior, and the Emotionality, Activity and Sociability scale (sociability subscale). Covariates were occupational class, maternal education and age at 2D:4D measurement. 

Results: 2D:4D was not associated with ASDs in males (adjusted odds ratio (OR) per 1-standard deviation increase in mean 2D:4D, 0.88 [95% confidence interval (CI) 0.65-1.21], p=0.435) or females (adjusted OR=1.36 [95% CI 0.81-2.28], p=0.245). Similar associations were observed after further adjustment for IQ. There was one weak association, discordant with the EMB theory, between reduced coherence and increased left 2D:4D in males (adjusted OR=1.15 [95% CI 1.02-1.29], p≤0.05). Given multiple comparisons, this may be consistent with chance.

Conclusions: In this population-based study, there was no association between 2D:4D and ASD diagnosis. There was weak, inconsistent evidence of association between 2D:4D and risk of ASD. These results are discordant with the extreme male brain theory of autism.

See more of: Epidemiology
See more of: Epidemiology