Dairy Intake and Uterine Fibroid Development: A Prospective Study

Abstract

Background:

Dairy intake has been associated with lower fibroid incidence in some studies, but none used standardized serial ultrasound screening to detect fibroids.

Methods:

We examined dairy intake and fibroid development in the Study of Environment, Lifestyle and Fibroids, a prospective cohort (2010–2018) of 1,610 Black/African American women with no prior clinical diagnosis of fibroids. At the baseline, participants completed a Food Frequency Questionnaire about their intake of daily milk, cheese, yogurt, and total dairy. At three follow-up visits, conducted approximately every 20 months, participants updated their cow’s milk intake. Incident cases were those with ultrasound-detected fibroids among those fibroid-free at the baseline ultrasound. We used Cox proportional hazards models to estimate adjusted hazard ratios for fibroid incidence with 95% confidence intervals (CI). For fibroid growth, we calculated the change in log-volume from one visit to the next.

Results:

The majority (83%) of participants consumed <0.5 cups of milk/day. Neither dairy nor milk intake was appreciably associated with fibroid incidence. However, the baseline total dairy consumption of ≥1 versus <1 cup/day was associated with a 19% decrease (95% CI = −34%, −0.8%) in fibroid growth over the first 20-month interval. The baseline milk intake of ≥0.5 versus <0.5 cups/day was associated with a 26% decrease in growth (95% CI = −39%, −11%) in the same interval. We did not observe similar associations between time-varying milk intake and growth over other study intervals.

Conclusions:

The data from this prospective ultrasound study provide some evidence that dairy intake may reduce fibroid growth.