Manuscript title: limited suitability for single item work ability to replace work ability index: a Brazilian cross-sectional study

Abstract The Work Ability Index (WAI) evaluates how workers are at present and in the near future with respect to work demands, health, and mental resources. Since this questionnaire is time consuming, a single-item question (work ability score - WAS) has been used to replace the WAI. The aim of this study was to investigate the correlation between the work ability index (WAI) and WAS, adjusted by age, sex and occupation. Workers (N = 379) from different economic sectors answered a questionnaire addressing demographic information and the WAI. The data were analyzed using descriptive statistics, Spearman’s rank correlation coefficients and partial correlations. Moderate correlations were found between the WAI and WAS (rs=0,49). Stronger correlations were found between the WAI and other WAI Dimensions: Diagnosed Diseases, Work Demands and Work Loss (rs>0.60). The partial correlation results showed that the correlation between the WAI and WAS increased when adjusted by sex, age and occupation (r = 0.60), but remained lower than other coefficients. Therefore, we cannot recommend the use of WAS instead of the WAI for Brazilian workers according to the correlation found.