Disability was determined using the 12-Item Short Form Health Survey, version 2 (SF-12v2). The SF-12v2 is a reliable and valid measure of current impairment widely used in population surveys.41 The SF-12v2 included Mental Health, Social Functioning, and Role Emotional subscales and the Mental Component Summary. Each SF-12v2 norm-based disability score has a mean of 50, SD of 10, and range of 0 to 100. Lower scores indicated greater disability.
