The Epidemiology of cerebral palsy in Ontario, Canada: patterns of occurrence and effects of two maternal exposures
Bibliographic record
Abstract
Background: Cerebral palsy (CP) is a lifelong disorder of posture and movement and is the most common cause of physical disability in children. Since there is no cure available for CP, understanding causal mechanisms is essential to develop effective primary prevention strategies. Whereas plenty of research has examined temporal trends in overall CP rates, changes in CP rates by key sociodemographic characteristics over time have been scarcely described. Furthermore, limited evidence exists in the literature on the role of preconception and antenatal modifiable factors that lie early in the causal pathways that lead to CP. Objectives: This doctoral research aimed to (1) estimate the prevalence and temporal trends of CP in Ontario, Canada among children born in 2002–2017 both overall and by population characteristics; (2) examine the effect of maternal pre-gestational (PGDM) and gestational diabetes (GDM) on the risk of CP; and (3) assess the effect of exposure to maternal unintentional injury during pregnancy on the risk of CP.Methods: We created a longitudinal retrospective cohort of over 2 million in-hospital births with maternal and their own health records by linking several individual- and area-level provincial administrative health datasets in Ontario, Canada. All children were followed from birth until the end of follow-up in 2018 to ascertain the study outcome. PGDM was identified from an administrative data-derived registry for diabetes in the province. GDM and unintentional injuries were defined based on inpatient, outpatient, or emergency department (for injuries) diagnoses during the index pregnancy. We used a non-linear Poisson model to examine temporal trends in CP rates—overall and stratified by characteristics—in young children (0–4 years) born in the same year (referred as birth ‘cohort’) between 2002–2013 (n=1,587,087 live births) to allow for an equal follow-up time (4 years and 364 days) for all children. For the effects of exposure to maternal diabetes and injuries during pregnancy, we estimated crude and adjusted risk ratios using the Cox proportional hazards models to account for the unequal follow-up time in children.Results: CP prevalence increased gradually from 2002, peaked among children born in 2007, then steadily decreased in more recent years. CP rates were consistently higher in boys, children born early, small, or with birth defects, and children of young (<20 years), old (>40 years), primiparous, and grand multiparous (>4 previous live births) mothers and those with inadequate prenatal care; however, gaps by these characteristics have narrowed over time. Socioeconomic inequalities in CP persisted and remained stable over the study period.Children of mothers with PGDM showed an increased risk of CP (hazard ratio (HR) of 1.84 (95% confidence interval (CI): 1.59, 2.14) in the model adjusted for maternal sociodemographic and pre-existing factors). However, no similar associations were found for GDM (adjusted HR 0.91 (95% CI: 0.77, 1.06)). Maternal unintentional injury was also associated with a slightly higher risk of CP (HR 1.33 (95% CI: 1.18, 150) after adjusting for maternal sociodemographic and lifestyle factors).Conclusion: In this large population-based cohort of over 2 million live births, CP rates over time are on decreasing trend in more recent years. However, changes in CP rates differed by child, maternal, and sociodemographic characteristics. The increased risk of CP in children exposed to maternal PGDM and unintentional injuries observed in this research fills important gaps in knowledge about the role of maternal exposures on children’s neurodevelopment. Results of this thesis research not only lead to a better appreciation of the magnitude of the CP burden in Canada but also offer insights on potential causal mechanisms of CP. Ultimately, this work will contribute to developing preventative strategies to reduce the risk of this disabling disorder in Canada and elsewhere
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.007 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".