Oral contraceptives did not affect biochemical folate indexes and homocysteine concentrations in adolescent females

Objective: The study was designed to determine the impact of currently available oral contraceptive agents (OCAs), smoking, and alcohol on biochemical indexes of folate and vitamin B-12 in adolescent females. Design: Subjects completed a 3-day weighed food record along with a detailed lifestyle questionnaire that included questions on OCA, cigarette, and alcohol use. After subjects had fasted overnight, blood samples were collected and analyzed for levels of serum and red blood cell (RBC) folate and serum B-12 and homocysteine. Subjects/settings: Two hundred twenty-nine adolescent females (aged 14 to 20 years) were recruited from southern Ontario, Canada, by advertisements in newspapers. high schools universities, shopping malls, adolescent drop-in centers, and community groups. Statistical analyses performed: Multiple regression models were used to determine the effect of lifestyle factors and covariates (eg, dietary folate intake, supplemental folate intake, and age) on biochemical indexes. Results: OCA use, alcohol use, and smoking were not significantly associated with lower serum or RBC folate levels, after controlling for folate intake. Serum homocysteine levels were not associated with smoking or OCA use; however, we estimated a 13% higher concentration among alcohol users than nonusers. Smoking and alcohol use were not associated with serum B-12 levels, but OCA use was associated with an estimated 33% lower serum B-12 level than nonuse. Applications: Our findings provide no evidence to suggest that currently available OCAs have a negative impact on the folate status of adolescent females; thus, dietary advice designed to specifically encourage an increase in folate intake among adolescents who use OCAs is not supported. In contrast, serum B-12 levels were lower among OCA users than nonusers, which suggests that an interaction between OCA and some vitamins may persist. The suboptimal biochemical folate indexes of smokers may have more to do with the dietary quality of smokers than previously appreciated. Thus, efforts to improve dietary folate intakes of adolescents who smoke may be an important strategy for improving the folate status of young women.