Association between dietary inflammatory potential and breast cancer incidence and death: results from the Women’s Health Initiative

Abstract

Background:Diet modulates inflammation and inflammatory markers have been associated with cancer outcomes. In the Women's Health Initiative, we investigated associations between a dietary inflammatory index (DII) and invasive breast cancer incidence and death.Methods:The DII was calculated from a baseline food frequency questionnaire in 122 788 postmenopausal women, enrolled from 1993 to 1998 with no prior cancer, and followed until 29 August 2014. With median follow-up of 16.02 years, there were 7495 breast cancer cases and 667 breast cancer deaths. We used Cox regression to estimate multivariable-adjusted hazards ratios (HRs) and 95% confidence intervals (95% CIs) by DII quintiles (Q) for incidence of overall breast cancer, breast cancer subtypes, and deaths from breast cancer. The lowest quintile (representing the most anti-inflammatory diet) was the reference.Results:The DII was not associated with incidence of overall breast cancer (HRQ5vsQ1, 0.99; 95% CI, 0.91–1.07; Ptrend=0.83 for overall breast cancer). In a full cohort analysis, a higher risk of death from breast cancer was associated with consumption of more pro-inflammatory diets at baseline, after controlling for multiple potential confounders (HRQ5vsQ1, 1.33; 95% CI, 1.01–1.76; Ptrend=0.03).Conclusions:Future studies are needed to examine the inflammatory potential of post-diagnosis diet given the suggestion from the current study that dietary inflammatory potential before diagnosis is related to breast cancer death.

Associations between Diet Quality Scores and Risk of Postmenopausal Estrogen Receptor-Negative Breast Cancer: A Systematic Review

“…Among the 7 studies included, 1 population-based casecontrol study was conducted in Germany (26); 3 prospective cohort studies were conducted in the United States [Nurses' Health Study (NHS) (14,15) and Women's Health Initiative cohort study (21)]; and the other 3 were conducted in European countries [European Prospective Investigation into Cancer and Nutrition Cohort (EPIC) study (27), Swedish Women's Lifestyle and Health cohort study (28), and Netherlands cohort study (29) Duplicates removed (n = 50) FIGURE 1 Literature search flow chart.…”

“…In the population-based case-control study of postmenopausal breast cancer in Germany, 428 ER−/progesterone receptor-negative (PR−) cases from the MARIE (Mammary Carcinoma Risk factor Investigation) study showed no association between the DII and risk of the ER−/PR− breast cancer (OR comparing the top to bottom quintiles of the DII: 0.87; 95% CI: 0.63, 1.20; P-trend = 0.24) (26). In the United States, the Women's Health Initiative observational study followed 70,998 women for a median of 16 y, with a total of 381 ER−/PR− cases (21). Analysis was completed separately by human epidermal growth factor 2 status, and a higher DII was associated with a higher risk (30).…”

“…Overall, the European studies showed mixed results, with the larger studies showing a significant inverse relation and the smaller studies finding no association. Data from the United States came from only 2 cohorts, and tended to report inverse associations between dietary quality scores and risk of postmenopausal ER− cancer (14,15,21). For the various Mediterranean diet scores, slightly more consistency was observed, with 2 out of 3 European studies (27)(28)(29) and 1 US study (15) showing a significant inverse association.…”

“…Systematic reviews have examined the current literature on the association between dietary patterns that reflect existing eating habits and the risk of breast cancers (17)(18)(19)(20) and found a possible inverse association, but ER status was not distinguished. Diet quality scores are constructed with predetermined intake criteria and used to evaluate the healthfulness of food choices (15,21). They are generally similar in several characteristics, such as emphasis of fruits and vegetables and de-emphasis of red and processed meats.…”

An Adolescent and Early Adulthood Dietary Pattern Associated with Inflammation and the Incidence of Breast Cancer

“…[31] A meta-analysis of adult dietary patterns derived using PCA/factor analysis has suggested an 7% reduced risk of breast cancer for women in the highest category of adult prudent/healthy dietary pattern score (95% CI, 0.88 to 0.98). [7] Among the three study populations that have examined adult dietary inflammation potential and breast cancer outcomes, two reported no significant association with overall breast cancer risk[32–34] and one reported a borderline positive association between DII and breast cancer. [35] To our knowledge, the NHS II cohort is the only study to examine adolescent dietary patterns derived by PCA while no studies have examined an adolescent diet DII and breast cancer risk.…”