Objective: to assess the impact of neonatal abstinence syndrome (NAS) on school performance.
Design: retrospective cohort study.
Setting: population (New South Wales, Australia).
Study population: children born between July 1, 2000 and December 31, 2006 (605 094 children). The authors linked the data of four population databases: a perinatal database that included information on discharge diagnoses, another with demographic data, a third one with mortality data, and a fourth one with school testing results. Still births, infants born at less than 23 or more than 44 weeks’ gestation or with unknown gestational age (GA) and children that died before the first school test were excluded.
Risk factor assessment: children discharged from hospital with a diagnosis of NAS (code P96.1 in the Australian Modification of the International Classification of Diseases) (n = 2234). These children were compared with two groups: a matched cohort (MC) matched 2:1 for sex, GA, birth year and socioeconomic status (n = 4330) and the general population cohort (GC) (n = 598 265).
Outcome measurement: a test was administered within the framework of the national education programme (score, 0-1000) at grades 3, 5, 7 and 9 (ages 8-9, 10-11, 12-13 and 14-15). There is an established National Minimum Standard (NMS), and children that score below it cannot progress to the next grade and require additional support. The authors used ANOVA to performed pair-wise comparisons of the scores. Logistic regression analysis was performed, including potential confounding variables in the model: sex, prematurity, indigenous status, school remoteness and parental educational attainment.
Main results: linkage between the perinatal database and school test results was achieved in 468 239 out of the 604 829 children (77.4%), and this percentage was significantly lower in children with NAS (1668 out of 2234 [75.6%]; P = .003).
Nearly half of the parents of children with NAS had an education level below grade 9 (44% compared to 18.4% in the MC and 17.1% in the GC; P < .001). Most of these children attended public schools (88.3% compared to 71% in the MC and 68.1% in the GC).
Children with NAS scored significantly lower in school tests. At age 12-13 years, 37.7% did not achieve the NMS (compared to 18.4% of the MC [odds ratio (OR), 2.1; 95% confidence interval (95 CI), 1.7 to 2.4] and 14.5% of the GC [OR, 3.6; 95 CI, 2.9 to 4.3]). This difference progressed from grade 3 to grade 7. The risk of not meeting the NMS was also independently associated with NAS (adjusted odds ratio [aOR]: 2.5; 95 CI, 2.2 to 2.7).
In children with NAS, the risk factors to fail to meet the NMS were indigenous status (aOR, 1.7; 95 CI, 1.4 to 2.1), male sex (aOR, 1.3; 95 CI, 1.2 to 1.6) and low parental educational attainment (aOR, 1.3; 95 CI, 1.1 to 1.6). These factors and prematurity also increased the risk of failing to achieve NMS in the GC.
Conclusion: the neonatal diagnosis of NAS was strongly associated with poorer school performance. Parental educational attainment can attenuate this effect.
Conflicts of interest: none disclosed.
Funding source: partially funded by the Cerebral Palsy Alliance of Australia.