Dairy Intake and Uterine Fibroid Development: A Prospective Study.

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.