Mt. Goodman et al., Case-control study of plasma folate, homocysteine, vitamin B-12, and cysteine as markers of cervical dysplasia, CANCER, 89(2), 2000, pp. 376-382
BACKGROUND. An association between B-complex vitamins and related compounds
with the development of cervical neoplasia is biologically plausible, yet
to the authors' knowledge epidemiologic investigations of these potential b
iomarkers are limited.
METHODS. A case-control study was designed to examine the relation between
plasma folate, homocysteine, vitamin B-12, and cysteine and early, premalig
nant changes in cervical epithelial cells among women identified from sever
al clinics on Oahu, Hawaii, between 1992 and 1996. Fasting blood samples fo
r plasma nutrient analysis, cervical smears for cytologic diagnosis, exfoli
ated cervical cells for human papillomavirus DNA testing by polymerase chai
n reaction, and a personal interview were obtained from 185 women with atyp
ical squamous cells of undetermined significance (ASCUS) of the cervix, 147
women with squamous intraepithelial lesions (SIL), and 191 women with cyto
logically normal (Papanicolaou) smears.
RESULTS. Age-adjusted and ethnicity-adjusted mean plasma concentrations of
cysteine, but not other nutrients, were significantly lower among ASCUS cas
es (P = 0.006) and SIL cases (P = 0.01) than controls. A positive trend in
the odds ratio for SIL but not ASCUS was found for increased plasma homocys
teine concentrations, but this finding was not statistically significant. H
igh plasma levels of cysteine were associated with a reduced risk of ASCUS
(P value for trend - 0.006), with an odds ratio of 0.3 (95% confidence inte
rval, 0.2-0.7) for the highest compared with the lowest quartile of cystein
e concentration. A weak, negative relation between cysteine and the develop
ment of low grade SIL (LSIL) but not high grade SIL (HSIL) also was found.
CONCLUSIONS, The results of the current study do not support the hypothesis
that folate, homocysteine, or B-12 are markers of cervical dysplasia risk.
A possible inverse association between plasma cysteine concentrations and
the risk of cervical dysplasia needs further study. (C) 2000 American Cance
r Society.