Table 2.

Relation of season to mammographic breast density in premenopausal women

Fall (reference)0.118
  • * The number of women recruited in spring, summer, fall, and winter was 249, 184, 218, and 90, respectively.

  • β values are estimated from linear regression analysis; breast density is treated as a continuous variable. β values represent absolute mean difference in breast density comparing winter, spring, or summer with fall (the adjusted mean in fall, the season of reference, is 39.4%). β values are adjusted for age (y) and body mass index (kg/m2). Pseason = 0.028 (3 degrees of freedom).