Abstract
IMPORTANCE: Neurodevelopmental disorders (NDDs) such as autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and intellectual disability contribute to one-tenth of the global burden of mental and neurologic disorders. The burden of NDDs is not well documented in Africa. OBJECTIVE: To assess the prevalence, risk factors, and comorbidities of NDDs in young Kenyan children. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study was conducted among children aged 6 to 9 years residing in the Kilifi Health and Demographic Surveillance System in Kenya. In stage I of the study, children were screened for NDDs from March 16, 2015, to September 14, 2016; those with a positive screening result and a randomly selected proportion of those with a negative screening result were invited to undergo clinical evaluation to confirm the diagnosis (stage II). EXPOSURES: Adverse perinatal events, medical and family history, and socioeconomic status. MAIN OUTCOMES AND MEASURES: Prevalence of NDDs was estimated, and risk factors and medical comorbidities associated with NDDs were assessed using generalized linear models and link functions. RESULTS: Of the 11 223 children screened in stage I, 5646 (50.3%) were males, and mean (SD) age was 7.6 (0.96) years. A total of 522 children had an NDD confirmed in stage II, with an overall adjusted prevalence of 9.1% (90.8 [95% CI, 83.4-98.6] cases per 1000 children), which differed by sex (237 of 5577 females [4.2%] vs 285 of 5646 males [5.0%]; P = .045). The NDDs with the highest prevalence were ADHD (50.8 [95% CI, 45.2-57.1] cases per 1000 children) and cognitive impairment (27.1 [95% CI, 22.9-31.9] cases per 1000 children); ASD was also common (15.6 [95% CI, 12.6-19.1] cases per 1000 children). Co-occurrence of NDDs was reported in 118 children (22.6%; 95% CI, 19.2%-26.5%). Key factors associated with occurrence or onset of NDDs included adverse perinatal events (adjusted risk ratio [ARR], 1.64; 95% CI, 1.29-2.09), febrile infections (ARR, 1.28; 95% CI, 1.05-1.56), eating soil (ARR, 1.45; 95% CI, 1.13-1.85), snoring (ARR, 1.50; 95% CI, 1.27-1.76), and being landless (ARR, 1.32; 95% CI, 1.12-1.56). Head injuries were unique to developmental conditions and febrile infections to neurologic conditions, with many risk factors shared. Common medical comorbidities for NDDs after adjusting for attrition and screening specificity included motor neuron dysfunction (ARR, 2.79; 95% CI, 2.18-3.56) and malnutrition (ARR, 1.80; 95% CI, 1.37-2.39). CONCLUSIONS AND RELEVANCE: NDDs were common in school-aged children in this rural area of Kenya, and the findings suggest their occurrence was associated with preventable environmental risk factors. These disorders and associated comorbidities should be identified and addressed in children in Africa.