The effect of weight change on changes in breast density measures over menopause in a XXXX screening cohort.

@entity1 @entity1017 @entity0 @entity353
INTRODUCTION: High weight and high percent mammographic breast density are both @entity0 risk factors, but are negatively correlated. Therefore we wanted to obtain more insight in this apparent paradox. METHODS: We investigated in a longitudinal study how weight change over menopause is related to changes in mammographic breast features. 591 @entity1 of the EPIC-NL cohort, were divided into 3 groups according their prospectively measured weight change over menopause: 1) @entity353 (> -3.0  %), 2) stable weight (between -3.0  % and +3.0  %) and 3) @entity1017 (>3.0  %). SPSS GLM univariate analysis was used to determine both the mean breast measure changes in, and the trend over the weight change groups. RESULTS: Over a median period of 5  years, the mean change in percentage density in these groups was -5.0  % (95  % CI: -8.0; -2.1), -6.8  % (95  % CI: -9.0; -4.5) and -10.2  % (95  % CI: -12.5; -7.9), respectively (p-trend   =   0.001). The mean change in dense area was -16.7  cm(2) (95  % CI: -20.1; -13.4), -16.4  cm(2) (95  % CI: -18.9; -13.9) and -18.1  cm(2) (95  % CI: -20.6; -15.5), respectively (p-trend   =   0.437). Finally, the mean change in nondense area was -6.1  cm(2) (95  % CI: -11.9; -0.4), -0.6  cm(2) (95  % CI: -4.9; 3.8) and 5.3  cm(2) (95  % CI: 0.9; 9.8), respectively (p-trend   <   0.001). CONCLUSIONS: Going through menopause is associated with a decrease in both percent density and dense area. The decrease in percent density is largest in @entity1 who gain weight, due to an increase in the nondense tissue. The decrease in dense area is not related to weight change. So the fact that both high percent density and high weight or @entity1017 are associated with high @entity0 risk, can probably not be explained by an increase (or slower decrease) of dense area in @entity1 gaining weight compared to @entity1 losing weight or staying stable weight. These results suggest that weight and dense area are presumably two independent @entity0 risk factors.
