Objective: To provide nationally representative prevalence estimates of disability associated with prior head injury with loss of consciousness in the U.S. and to examine associations between prior head injury and disability.

Methods: Cross-sectional analysis of 7,390 participants aged ³40 years in the 2011-2014 National Health and Nutrition Examination Surveys (NHANES). Head injury with loss of consciousness was assessed by self-report. Domains of disability were assessed using a standardized structured questionnaire and measured grip strength. Logistic regression models adjusted for demographic, socioeconomic/behavioral, and medical comorbidity variables were used. Multiple imputation was used to account for missing covariate data.

Results: Mean age of participants was 58 years, 53% were female, 71% were non-Hispanic white, and 16% had a history of head injury. Overall, participants with a history of head injury had higher prevalence of disability in at least one domain of functioning compared to individuals without a history of head injury (47.4% versus 38.6%, p<0.001), with the highest prevalence of disability in the domains of mobility and work productivity. In fully adjusted models, head injury was significantly positively associated with disability in all domains assessed on the standardized questionnaire (all p<0.05), but not with upper extremity grip strength (all p>0.05).

Conclusions: 47.4% of individuals aged ≥40 years in the U.S with a history of head injury are living with disability in at least one domain of functioning, corresponding to approximately 11.4 million affected individuals. This significant burden of disability suggests that efforts are needed to improve functioning among individuals with head injury.