Fig. 3

Smoking and breast cancer risk in women with BRCA mutations (n = 9) and family history (n = 9). Each bar is divided based on the proportion of included studies that demonstrated an increased risk, decreased risk, or no association with risk of breast cancer due to the specified smoking exposure. Within each smoking exposure, each study is represented only once. However, because the category “all smoking behaviors” combines the results of all other exposure categories, studies may be represented more than once, if the results differ by exposure (e.g., increased risk with current smoking and no association with past smoking). Numbers on the “all smoking behaviors” bars indicate the range of risk estimates from studies when reported as a ratio measure (OR/RR/HR). Results from studies reporting only p values or other measures that did not indicate magnitude of effect are not included in these ranges. A Each bar in the figure represents all of the included studies (n = total number of studies) that reported results on the specified smoking exposure in women with BRCA mutations, separated by BRCA mutation, if provided. Please see Tables 1 and 2 for all studies cited. B Each bar in the figure represents all of the included studies (n = total number of studies) that reported results on the specified smoking exposure in women with family history. Please see Additional file 4: Table S1 and Additional file 5: Table S2 for all studies cited