Variation in season of birth in singleton and multiple births concordant for autism spectrum disorder

Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
Paediatric and Perinatal Epidemiology (Impact Factor: 3.13). 04/2008; 22(2):172-9. DOI: 10.1111/j.1365-3016.2007.00919.x
Source: PubMed


Patterns of seasonal variation in births in some neuropsychiatric conditions have been found in previous research; however, no study to date has examined these disorders for seasonal variation in singletons and multiple births separately. This study aimed to determine whether the birth date distribution for individuals with autism spectrum disorders (ASD), including singletons and multiple births, differed from the general population. Two ASD case groups were studied: 907 singletons and 161 multiple births concordant for ASD. Two control groups were obtained from registered births of singletons and multiples.
Results of the non-parametric time-series analyses, where day of birth was used, suggested there were three peaks in ASD singletons and ASD concordant multiple births. Roughly, the peaks were in April, June and October for singletons and about 2–4 weeks earlier in multiples. Results from multivariable Poisson regression, where month of birth was used, indicated that ASD concordant multiple births in males tended to be higher than expected in March, May and September (with borderline statistical significance), but were 87% less in December (P < 0.05), as compared with January. Overall, the patterns of relative risk estimates from Poisson regression are similar to findings from the non-parametric time-series approach, but are not exactly congruent. It is important to note that indications of seasonality may be sensitive to the selection of time cut-points and therefore an arbitrary binning of time can either mask existing trends or falsely indicate the presence of a trend. The presence of seasonal trends in ASD singletons and concordant multiple births suggests a role for non-heritable factors operating during the pre- or perinatal period, even among cases with a genetic susceptibility.

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    • ", supported by others showing seasonality as a driver of autism [5] [6], although not all reports agree [18] Possible effects discussed below Possible mechanisms discussed below, but an important point in these constructs is that native folates are UV-A labile and easily oxidised [43], while vitamin D requires UV radiation for its synthesis and both are linked to autism risk "
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    Medical Hypotheses 04/2013; 80(6). DOI:10.1016/j.mehy.2013.03.003 · 1.07 Impact Factor
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    • "This having been said, research suggests that maternal, placental, and child serotonin may all interact with environmental variables to influence brain development (Bonnin et al., 2011; Zhang et al., 2010). In the case of ASD, the replicated finding of seasonal fluctuations in brain 5-HTT binding (Willeit and Praschak-Rieder, 2010) and autism births (Gadow and DeVincent, 2012; Lee et al., 2008), the effects of seasonal light cycles on serotonin signaling in the brain mediated by the circadian system (Ciarlegio et al., 2011), and possible involvement of circadian system regulatory genes in autism (Hu et al., 2009) all suggest multiple avenues of inquiry. Alternatively, our finding that the high expressing L A /L A genotype was associated with more severe ASD social deficits combined with research indicating (a) lower levels of brain 5-HTT binding in adults with ASD and correlation with social cognition deficits (Nakamura et al., 2010), (b) reduction in cortical serotonin 2A receptors in adults with Asperger syndrome and association with social communication deficits (Murphy et al., 2006), but (c) higher 5-HTT levels in non-ASD adults with the L A /L A genotype (Willeit and Praschak-Rieder, 2010) suggest possible disruption of neuronal homeostatic mechanisms (Ramocki and Zoghbi, 2008); nevertheless, divergent hypotheses based on results from neurodevelopmental, animal, and human cell line studies are also plausible (Azmitia et al., 2011). "
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    • "Although the data suggest that reading disorders may be caused by high testosterone levels, the data on autism were not significant. Other investigators [21] studied whether births at certain months of the year were associated with autism. They reported peaks of autism in April, June, and October for single births and 1 month earlier in March, May, and September for multiple births in males. "
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