Prevalence, Pattern and Factors Associated with Developmental Delay amongst Under-5 Children in Nigeria: Evidence from Multiple Indicator Cluster Survey 2011-2017.

Background: Children develop dynamically, and when a child fails to reach age-appropriate developmental milestones compared to their peers, it is considered a developmental delay. In developing nations like Nigeria, several demographics, socioeconomic, childcare and external factors may influence the highly individualised process. This study assessed the prevalence and pattern of developmental delay, across Nigeria's geopolitical zones including identified factors associated with developmental delay, providing insight for appropriate interventions to prevent disability in affected children.

Methods: This was a secondary analysis of data from the Multiple Indicator Cluster Survey (MICS), which was carried out in rounds 4 (2011) and 5 (2016/2017). Every 5 years, the UNICEF-supported MICS cross-sectional household survey is carried out using the cluster sampling method. A semi-structured, questionnaire administered by the interviewer was used to obtain individual and household-level data. This study comprised a weighted sample of 17,373 under-5 children who had complete data from both survey rounds on characteristics deemed significant for the study. Data were analysed using SPSS version 23. Using the Chi-square test and multivariate binomial logistic regression, factors linked to developmental delay were identified, with 95% confidence intervals (CIs) provided and the significance level set at 5%.

Results: The mean age and sex distribution of the children surveyed in both rounds was comparable, with a male preponderance of 51.2% in round 4 and 50.4% in round 5. In both round 4 (51.2%) and round 5 (49.0%), the Northeast zone had the highest prevalence of overall developmental delay while the least prevalence was seen in the Southwest zone (20.3%) and the Southeast zone (14.7%) in round 4 and round 5, respectively. Across all the zones, delay in the literacy-numeracy domain of development was the most prevalent, with the highest (91.3% and 86.7%, respectively) in the Northeast zone during both rounds of the survey. Delay in the physical domain was, however, the least prevalent form of developmental delay across the zones, with the least in South South (20.6%) and Southeast (5.4%) in rounds 4 and 5. The odds of developmental delay were 1.5 and 1.7 times higher amongst children 4 years old than 3 years old in both rounds of the survey. The likelihood of having developmental delay was found to increase with the severity of stunting amongst the children during both rounds of the survey (odds ratio [OR] =1.5; 95% CI = 1.20-1.78 in round 4 and OR = 1.4; 95% CI = 1.16-1.58 in round 5). Children from the poorest wealth index had higher odds of developmental delay (OR = 5.8; 95% CI = 4.92-6.82 in round 4 and OR = 2.5; 95% CI = 1.99-3.10 in round 5).

Conclusion: The prevalence of developmental delay is high across all zones; however, the burden varies amongst them. The age of the child, nutritional status and wealth index were indicators of developmental delay in Nigerian under-5 children. This underscores the need for surveillance and interventions focussed on improving child literacy, nutritional status and household standard of living across the zones.