Author's response to reviews Title:How age and sex affect the erythrocyte sedimentation rate and C-reactive protein in early rheumatoid arthritis. Authors:

Title:How age and sex affect the erythrocyte sedimentation rate and C-reactive protein in early rheumatoid arthritis. This study attempts to determine the impact of age, gender and BMI on the erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) in early rheumatoid arthritis. The findings are of interest but such studies are challenging to perform well given all of the potential confounders. Indeed, this study has a number of limitations, listed below by section in the manuscript. 1. Introduction: " Acute phase reactants are commonly used to measure the extent of inflammation in rheumatoid arthritis (RA)… " I would recommend revising to qualify this since no acute phase reactant can be or should be used as a sole measure of disease activity; it might be better to say " Acute phase reactants are commonly used as a measure of inflammation in RA "