Dietary intake of at least 300 IU per day was associated with a significant lower risk of estrogen receptor (ER)–positive breast cancer in the CPS II Nutrition cohort (RR Z 0.74; 95% CI Z 0.59–0.93; p for trend Z 0.006), but not of ER-negative disease (RR Z 1.35; 95% CI Z 0.79–2.33; p trend Z 0.82) (22) (Fig. 2).