CUERNAVACA, Mexico--Consumption of folate and vitamin B12 are inversely related to risk of breast cancer, according to a population-based case-control study held in Mexico (Cancer Epidemiol Biomarkers Prev, 15, 3:443-8, 2006).
Researchers from the Instituto Nacional de Salud Publica and Botston's Harvard School of Public Health and Medical School interviewed 475 women aged 23 to 87 years (median age, 53 years) diagnosed with incident breast cancer to obtain data on breast cancer risk factors and gathered data on their usual diet using a food frequency questionnaire. Using a national sampling frame, the researchers selected 1,391 control subjects from the Mexico City population, aged 18 to 82 years (median age, 49 years). Compared with women in the lowest quartile, the odds ratio for breast cancer for women in the highest quartile of folate intake was 0.64 and 0.32 for vitamin B12 intake. Among postmenopausal women in particular, intakes of folate and vitamin B12 were associated with a lower risk of breast cancer. The inverse association of folate and breast cancer was stronger among women who consumed a high level of vitamin B12 as compared with women consuming diets low in vitamin B12.
The researchers concluded high intakes of folate and vitamin B12 were independently associated with decreased breast cancer risk in this cohort, particularly among postmenopausal women.