The Relationship Between Unmetabolized Folic Acid and Serum Folate Concentrations and Cancer Risk in Older US Adults

ABSTRACT THE RELATIONSHIP BETWEEN UNMETABOLIZED FOLIC ACID AND SERUM FOLATE CONCENTRATIONS AND CANCER RISK IN OLDER US ADULTS by Regine L. Baldauff Importance Several studies have reported an increase in serum and unmetabolized folic acid levels since the implementation of folic acid fortification (January 1, 1998). However, the literature published during the post-folic acid fortification period is controversial with regards to the safety and potential risk for cancer in non-target populations. Objective To study the association between unmetabolized folic acid and serum folate and cancer in older US adults. Design, Setting, and Participants This is a cross sectional study using data from National Health and Nutrition Examination Surveys. Among 700 participants with identified unmetabolized folic acid, 147 cases were reported a history of having cancer from 1999-2002. Within the 7,981 subjects who had a recorded value for serum folate from 1999-2008; 1,459 reported a history of all cancer. Among the 4,007 women who had a recorded value for serum folate between 1999-2008; 288 reported a history of breast cancer. Main Outcome Measures Associations of unmetabolized folic acid and serum folate with all cancer and breast cancer was evaluated using a multivariable logistic regression analysis controlling for demographic and dietary intakes. Results Men and women without unmetabolized folic acid were 0.7 times less likely to develop cancer. Those over the age of sixty with the highest concentration of serum folate were 1.4 times more likely to have cancer than participants with lower serum folate concentrations. Women over the age of sixty with the highest concentration of serum folate were 1.8 times more likely to have breast cancer compared to women with lower serum folate concentrations. Conclusions and Relevance The presence of unmetabolized folic acid and high serum folate concentrations were related to an increased prevalence of cancer. Further research is warranted to investigate the cause and effect relationship