Erythrocyte membrane n-3 PUFA are inversely associated with breast cancer risk among Chinese women

The relationship between erythrocyte membrane n-3 PUFA and breast cancer risk is controversial. We
aimed to examine the associations of erythrocyte membrane n-3 PUFA with odds of breast cancer
among Chinese women by using a relatively large sample size. A case-control study was conducted including 853 newly diagnosed, histologically confirmed breast cancer cases and 892 frequency-matched
controls (5-year interval). Erythrocyte membrane n-3 PUFA were measured by GC. Logistic regression
and restricted cubic spline were used to quantify the association between erythrocyte membrane n-3
PUFA and odds of breast cancer. Erythrocyte membrane α-linolenic acid (ALA), docosapentaenoic acid
(DPA) and total n-3 PUFA were inversely and non-linearly associated with odds of breast cancer. The OR
values (95 % CI), comparing the highest with the lowest quartile (Q), were 0·57 (0·43, 0·76), 0·43 (0·32,
0·58) and 0·36 (0·27, 0·49) for ALA, DPA and total n-3 PUFA, respectively. Erythrocyte membrane EPA
and DHA were linearly and inversely associated with odds of breast cancer ((EPA: OR Q4 v. Q1  (95 % CI) =
0·59 (0·45, 0·79); DHA: OR Q4 v. Q1  (95 % CI) = 0·50 (0·37, 0·67)). The inverse associations were observed
between ALA and odds of breast cancer in postmenopausal women, and between DHA and oestrogen
receptor+ breast cancer. This study showed that erythrocyte membrane total and individual n-3 PUFA
were inversely associated with odds of breast cancer. Other factors, such as menopause and hormone
receptor status, may warrant further investigation when examining the association between n-3 PUFA
and odds of breast cancer.