Tj. Green et al., ORAL-CONTRACEPTIVES DID NOT AFFECT BIOCHEMICAL FOLATE INDEXES AND HOMOCYSTEINE CONCENTRATIONS IN ADOLESCENT FEMALES, Journal of the American Dietetic Association, 98(1), 1998, pp. 49-55
Objective The study was designed to determine the impact of currently
available oral contraceptive agents (OCAs), smoking, and alcohol on bi
ochemical indexes of folate and vitamin B-12 in adolescent females. De
sign Subjects completed a 3-day weighed food record along with a detai
led lifestyle questionnaire that included questions on OCA, cigarette,
and alcohol use. After subjects had fasted overnight, blood samples w
ere collected and analyzed for levels of serum and red blood cell (RBC
) folate and serum B-12 and homocysteine. Subjects/settings Two hundre
d twenty-nine adolescent females (aged 14 to 20 years) were recruited
from southern Ontario, Canada, by advertisements in newspapers, high s
chools, universities, shopping malls, adolescent drop-in centers, and
community groups. Statistical analyses performed Multiple regression m
odels were used to determine the effect of lifestyle factors and covar
iates (eg, dietary folate intake, supplemental folate intake, and age)
on biochemical indexes. Results OCA use, alcohol use, and smoking wer
e not significantly associated with lower serum or RBC folate levels,
after controlling for folate intake. Serum homocysteine levels were no
t associated with smoking or OCA use; however, we estimated a 13% high
er concentration among alcohol users than nonusers. Smoking and alcoho
l use were not associated with Serum B-12 levels, but OCA use was asso
ciated with an estimated 33% lower serum B-12 level than nonuse. Appli
cations Our findings provide no evidence to suggest that currently ava
ilable OCAs have a negative impact on the folate status of adolescent
females; thus, dietary advice designed to specifically encourage an in
crease in folate intake among adolescents who use OCAs is not supporte
d. In contrast, serum B-12 levels were lower among OCA users than nonu
sers, which suggests that an interaction between OCA and some vitamins
may persist. The suboptimal biochemical folate indexes of smokers may
have more to db with the dietary quality of smokers than previously a
ppreciated. Thus, efforts to improve dietary folate intakes of adolesc
ents who smoke may bean important strategy for improving the folate st
atus of young women.