Gestational age at birth and risk of intellectual disability without a common genetic cause

AbstractPreterm birth is linked to intellectual disability and there is evidence to suggest post-term birth may also incur risk. However, these associations have not yet been investigated in the absence of common genetic causes of intellectual disability, where risk associated with late delivery may be preventable. We therefore aimed to examine risk of intellectual disability without a common genetic cause across the entire range of gestation, using a matched-sibling design to account for unmeasured confounding by shared familial factors. We conducted a population-based retrospective study using data from the Stockholm Youth Cohort (n  = 499,621) and examined associations in a nested cohort of matched outcome-discordant siblings (n = 8034). Risk of intellectual disability was greatest among those born extremely early (adjusted OR24 weeks = 14.54 [95% CI 11.46–18.44]), lessening with advancing gestational age toward term (aOR32 weeks = 3.59 [3.22–4.01]; aOR37weeks = 1.50 [1.38–1.63]); aOR38 weeks = 1.26 [1.16–1.37]; aOR39 weeks  = 1.10 [1.04–1.17]) and increasing with advancing gestational age post-term (aOR42 weeks = 1.16 [1.08–1.25]; aOR43 weeks = 1.41 [1.21–1.64]; aOR44 weeks = 1.71 [1.34–2.18]; aOR45 weeks = 2.07 [1.47–2.92]). Associations persisted in a cohort of matched siblings suggesting they were robust against confounding by shared familial traits. Risk of intellectual disability was greatest among children showing evidence of ...
Source: European Journal of Epidemiology - Category: Epidemiology Source Type: research