INS and breast cancer: In the present study, although most comorbidities and medications that may be related to the exposure to human insulin and/or to breast cancer have been considered as potential confounders (Tables 1, 2 and 3), it was not able to neatly segregate the confounding effect of other indicators of diabetes severity such as glycemic control, which might also be highly correlated with the use of insulin, from the effect of insulin per se.