Motor development problems in infancy predict mental disorders in childhood: a longitudinal cohort study

The purpose of this study is to examine whether motor development problems in infancy predicted mental disorders later in childhood, taking a wide array of potential confounding variables into consideration. This longitudinal study included an unselected study population of 33238 newborn children from the Copenhagen area, Denmark. Data on the predictor variable, motor development problems at 8-10 months of age, were obtained from the community health nurses' systematic evaluation of the child's motor development during a home visit and stored in the Child Health Database. Data on outcome, diagnosed mental disorders before the age of 8 years, were obtained from the Danish National Patient Register. Potential confounding variables were obtained from the Child Health Database, the National Birth Register and the Civil Registration System. The prevalence of motor development problems at 8-10 months of age was 19.3%; the incidence of any diagnosed mental disorder from 11 months of age to the 8th birthday was 4.0%. Motor development problems were associated with an increased risk of being diagnosed with a mental disorder before the 8th birthday, adjusted odds ratio (AOR) 1.47 (1.29-1.67). Motor development problems were associated with later neurodevelopmental disorders, AOR 1.77 (1.52-2.06), in particular autism spectrum disorders, AOR 1.63 (1.31-2.03), hyperactivity/attention deficit disorders, AOR 1.29 (1.03-1.61) and disorders of intellectual disability, AOR 3.28 (2.39-4.49).

Motor development problems as early at 8-10 months of age were predictive of neurodevelopmental disorders before the 8th birthday. The findings call for clinical attention and more research on preventive potentials in the community child health care.

• Children with ASD, ADHD and ID have high prevalence of early motor development problems.

• Motor development problems in infancy predicted neurodevelopmental disorders before the 8th birthday. • This observation could improve early identification and prevention of mental health problems in childhood.