Lack of effects of dietary folate intake on risk of breast cancer: an updated meta-analysis of prospective studies.
BACKGROUND
Epidemiological findings are controversial relating to the relationship between dietary folate intake and the risk of breast cancer. We therefore conducted a meta-analysis of prospective cohort studies to clarify this association.


METHODS
PUPMED, EMBASE, and MEDLINE databases were searched for all relevant literature published in English from January 1, 1966 to August 2013. Summary relative risk (RR) and 95% confidence intervals (CIs) were calculated using a fixed or random effects model.


RESULTS
Dietary folate intake was not significantly associated with the risk of breast cancer. The combined PR with 95% CI for the highest vs. lowest category dietary intake of folate [fifteen studies; 1,836,566 participants and 24,083 patients with breast cancer] was 0.98 (0.90-1.05). Among subgroup analysis by menstrual status, hormonal status and the consumption of alcohol, methionine and vitamin B12, no significant association was observed for the dietary intake of folate and the risk of breast cancer. Dose-response analysis showed that a 220 μg/day increment in dietary folate intake was not associated with the risk of breast cancer.


CONCLUSIONS
Our findings indicate that dietary folate intake has no significant effect on the risk of breast cancer.
Department of Public Health, Qingdao University, Qingdao, China E-mail : lianhuacui520@hanmail.net.
Meng
M
Liu
Lian-Hua
LH
Cui
Ai-Guo
AG
Ma
Na
N
Li
Jin-Mei
JM
Piao
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D016022:Case-Control Studies; D004032:Diet; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage*; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D012306:Risk; D012307:Risk Factors
D005492:Folic Acid