Functional limitations as a risk factor for injury mortality among US adults ages 18-64: Results from the US National Health Interview Survey Linked Mortality Files

Previous studies suggest that there is relationship between functional limitations and injury. However, the temporal relationship between the limitation and the injury is not clear in these studies. Using the 1997-2004 National Health Interview Survey linked with the 1997-2006 Mortality Files, we study the association between functional limitations and injury mortality among those ages 18-64 years at the time of interview. Functional limitations were assessed using self- or proxy-reported limitations in performing basic actions and/or complex activities. Injury mortality rates by functional limitation status (at least one complex activity limitation; at least one basic actions difficulty with no complex activity limitation, and no complex activity limitation or basic actions difficulty) were calculated by sociodemographic subgroups. Cox proportional hazards models were used to assess the association between functional limitation and injury mortality, while controlling for known injury mortality risk factors. Results showed that people with at least one complex activity limitation had higher injury mortality rates than those with no limitations or difficulties in all sociodemographic subgroups. Cox models showed that after adjusting for other known injury mortality risk factors, persons with at least one complex activity limitation had 80% higher injury mortality risk (adjusted hazard ratio (AHR)=1.8; 95% CI=1.3-2.4), and those with only basic actions difficulty had 50% higher injury mortality risk (AHR=1.5; 95% CI=1.1-2.0) compared with those with no limitations or difficulties. The findings suggest that US adults ages 18-64 are at increased risk of injury deaths especially among those with limitations in complex activities.