Could the shaking of infants in early childhood be a leading source of unexplained intellectual disability in India?

Background: Data from India and other low and middle-income countries reveal high rates of parent-reported shaking of infants. Very high rates of developmental disability have been reported in India. The convergence of these observations provides an opportunity to understand the nature and consequences of a potentially harmful child discipline practice. Objective: To study whether caregiver shaking of an infant, even shaking insufficient to lead to an acute medical encounter, is associated with subsequent intellectual disability (ID). Methods: We conducted a matched case-control study at an academic medical center in Lucknow, India. We compared 75 children with ID of unknown etiology to 75 control children aged 24–72 months, matched by age, gender, maternal age, and maternal education. All children received a neurological evaluation and were IQ and lead tested. We questioned parents about early discipline practices, including shaking. If parents reported shaking, we asked them to demonstrate using a shaken baby simulator. We examined the association between ID and shaking using conditional logistic regression. Results: Children's median age was 43.4 (IQR: 25.1) months; 64% were boys. 24% of all study children were reported shaken before 24 months: 38.% of the case children and 9% of the controls. The adjusted odds of reported shaking of children with ID, before age 24 months, is 8.3 (95% CI: 2.4, 28.2) times higher than controls. Conclusion: Shaking children < 2 years of age in northern India is common; a strong association exists between early shaking and unexplained intellectual disability. Possibly contributing to intellectual disability, the role of infant shaking needs to be explored further. [ABSTRACT FROM AUTHOR]