Obese, postmenopausal women on proinflammatory diet at highest risk of breast cancer

A recent meta-analysis has confirmed the association of a proinflammatory diet with an increased risk of breast cancer, particularly among women who are obese, postmenopausal, and living in developing countries.

The databases of Scopus, PubMed, and Embase were searched for relevant studies. The authors extracted data from 21 studies that met the eligibility criteria, including 11 cohorts (336,085 participants, 20,033 incidence cases) and 10 case-control studies (9,833 cases, 12,752 controls). They used a random-effects model to calculate the relative risk (RR).

Compared with the lowest category, the highest dietary inflammatory index (DII) exhibited a 16-percent higher risk of breast cancer (95 percent confidence interval [CI], 1.06‒1.26; I², 62.8 percent; p<0.001).

The association between breast cancer risk and proinflammatory diet was more pronounced among women with body mass index ≥30 kg/m² (RR, 1.35, 95 percent CI, 1.07‒1.63, those in postmenopausal status (RR, 1.13, 95 percent CI, 1.04‒1.22), and populations from developing countries (RR, 1.79, 95 percent CI, 1.12‒2.47).

In subgroup meta-analyses, methodological covariates demonstrate more robust results among case-control studies (RR, 1.50, 95 percent CI, 1.20‒1.80), studies considering age-matched controls (RR, 1.56, 95 percent CI, 1.19‒1.93) and hospital-based controls (RR, 2.11, 95 percent CI, 1.58‒2.64), and cohort studies identified by prolong follow-up durations (RR, 1.13, 95 percent CI, 1.03‒1.22).

“Meta-analysis in methodological subgroups could improve results, less affected by heterogeneity, and suggested subclassification with important implications for future epidemiological designs and even clinical management,” the authors said.