The possible reasons for this finding may include an increase mechanical load stimulating bone synthesis, as suggested for the protective effect of obesity from osteoporosis development in the general population, a lower joint destruction in seronegative RA, the RA subset more associated with obesity, higher levels of estrogens found in obese subjects, having a bone protective effects, and role of adipokines, in particular adiponectin. This evidence concerns the gene ADIPOQ and rheumatoid arthritis.