Age-adjusted Baseline Neck Disability Index Values: An Analysis of Neck Pain Disability in the General American Population.

Study design: Survey-based, prospective study.

Objective: Identify age-adjusted baseline neck disability index (NDI) values in the American population.

Background: The NDI is the most widely used tool for assessing self-rated disability in patients with neck pain. Establishing baseline NDI values can aid in understanding the clinical impact of cervical spine pathologies and treatment interventions.

Materials and methods: An internet-based survey was distributed using the Connect ( TM ) platform powered by CloudResearch. Based on the latest U.S. census, this survey was designed to engage a demographically representative sample of the U.S. adult population. We captured 699 individuals, aiming for 100 people per each 10-year age group between 18 and 89. Participants scored their disability using the NDI survey. Mean NDI scores stratified by age group and sex were calculated for each cohort.

Results: A total of 699 participants were included with 352 (50.4%) males and 347 (49.6%) females and an age distribution closely aligning with national demographics. The overall mean NDI for the combined age groups was 16.5 with a 95% CI of 15.5 to 17.5. The 18 to 29 age group had the lowest mean NDI of 12.3 (95% CI: 10.4, 14.2). Mean NDI scores increased until the 60 to 69 age group with a mean of 20.1 (95% CI: 17.3, 23.0) with women having a mean NDI of 22.2 (95% CI: 18.8, 25.7) compared with men with 15.4 (95% CI: 10.3, 20.4). Mean NDI scores decreased in the 70 to 79 and 80 to 89 age groups.

Conclusion: This is the first study to assess age-adjusted baseline values of NDI in the U.S. population. Our findings demonstrate a disproportionate distribution of disability ratings across age groups. These data are important for health care professionals as it provides age and sex-specific levels of disability.

Level of evidence: Level III.