Dairy consumption during adolescence and endometriosis risk

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Dr. Holly Harris

A prospective cohort study in the American Journal of Obstetrics & Gynecology (AJOG) has concluded that consumption of dairy products during adolescence-specifically yogurt and ice cream-may reduce risk of a subsequent endometriosis diagnosis.

“No previous studies had looked at whether diet during adolescence could influence an endometriosis diagnosis,” said co-author Holly Harris, ScD, MPH, assistant professor of epidemiology at the Fred Hutchinson Cancer Research Center in Seattle. 

“Adolescence may be a critical window of exposure because endometriosis symptom onset often occurs during this time period,” Dr. Harris told Contemporary OB/GYN. “Furthermore, dietary exposures during adolescence have been linked to hormonally related conditions diagnosed in adulthood, thus we hypothesized that adolescence might  be a crucial time period for diet to influence future endometriosis diagnosis.”

Methods
The study is part of the Nurses’ Health Study II, which has prospectively collected data since 1989.

In 1998, when participants were between the ages of 34 and 51, they completed a 124-item food frequency questionnaire about their high school diet (HS-FFQ). Among 32,868 premenopausal women from 1998 to 2013, there were 581 cases of endometriosis, which was defined as self-reported, laparoscopically confirmed disease.

Results
Women who consumed more than four daily servings of dairy foods during adolescence had a 32% lower risk of endometriosis during adulthood (95% confidence interval [CI]; 0.47 to 0.96; P_trend= 0.04) compared to women consuming one or few servings per day.The association was similar for both low-fat and high-fat dairy foods.

For instance, women who consumed at least two servings of yogurt per week as an adolescent had a 29% lower risk of endometriosis (95% CI: 0.52 to 0.97; P_trend = 0.02) versus those consuming less than one serving per week. Likewise, women who consumed at least one daily serving of ice cream during adolescence had a 38% lower risk of endometriosis (95% CI: 0.40 to 0.94; P_trend = 0.20) compared to those who consumed less than one serving per week.

Conclusions
“The lower risk of endometriosis among those who consumed more ice cream is intriguing because we do not usually associate ice cream intake with beneficial health outcomes,” Dr. Harris said. “We speculate that consumption of ice cream and yogurt may influence the microbiome in a beneficial manner, resulting in the dampening of endometriosis-related pelvic pain during adolescence, thereby reducing the risk of visceral hypersensitivity and perhaps amplifying the symptoms of endometriosis over one’s life span. But more research is needed to evaluate this hypothesis.” 

In addition, because endometriosis is an inflammatory condition, it has been postulated that diary and calcium may reduce oxidative and inflammatory stress. “However, more rigorously designed studies are needed before dietary modifications can be recommended to specifically address endometriosis symptoms or incidence at any age,” Dr. Harris said. “Nonetheless, our study does point to adolescence as a critical time window and potentially indicates that dietary habits during this period could impact endometriosis outcomes.”

Limitations
Two limitations of the study are that it relied on long-term recall by the participants and that the make-up and intake of dairy products have changed over the decades.

Dr. Harris said more funded research in this area would allow examination of other dietary factors in an adolescent population, before broader dietary recommendations can be proposed. 

Disclosures:

Dr. Harris reports no relevant financial disclosures.