Ethnic distribution of factor V Leiden in 4047 men and women. Implications for venous thromboembolism screening.
OBJECTIVE
To estimate ethnic-specific prevalence rates of factor V Leiden, an inherited defect of hemostasis associated with risk of venous thrombosis.


METHODS
Survey of 4047 American men and women participating in the Physicians' Health Study (PHS) or in the Women's Health Study (WHS). All study participants were free of myocardial infarction, stroke, or venous thrombosis.


METHODS
Prevalence of G1691A Leiden mutation in the gene coding for coagulation factor V was determined in the PHS group using polymerase chain reaction techniques and, in the WHS group, a second-generation activated protein C (APC)-resistance screening test with genetic confirmation of all borderline and low-value results.


RESULTS
In 2468 Caucasian Americans, carrier frequency of factor V Leiden was 5.27% (95% confidence interval [CI], 4.42%-6.22%). Carrier frequency was 2.21% in 407 Hispanic Americans, 1.23% in 650 African Americans, 0.45% in 442 Asian Americans, and 1.25% in 80 Native Americans. Thus, prevalence of factor V Leiden was less among minority subjects (P=.001). Carrier frequencies were similar in Caucasian men and women (5.53% vs 4.85% respectively, P=.5).


CONCLUSIONS
These data indicate that prevalence of factor V Leiden is greater among Caucasians than minority Americans. These data have implications for clinicians considering whether to screen for factor V Leiden in high-risk groups such as those with prior venous thromboses or coexistent defects of anticoagulation and women at risk for postpartum thrombosis or seeking oral contraceptives.
Ridker
P M
PM
Division of Preventive Medicine, Brigham and Women's Hospital, Boston, MA 02215-1204, USA. pmridker@bics.bwh.harvard.edu
Miletich
J P
JP
Hennekens
C H
CH
Buring
J E
JE
D044383:Black People / Q000235:genetics; D003430:Cross-Sectional Studies; D005165:Factor V / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D006579:Heterozygote; D006630:Hispanic or Latino / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016133:Polymerase Chain Reaction; D015995:Prevalence; D011486:Protein C; D044469:Racial Groups / Q000235:genetics*; D012307:Risk Factors; D013924:Thrombophlebitis / Q000097:blood / Q000208:ethnology* / Q000235:genetics*; D044465:White People / Q000235:genetics; D001741:Black or African American
D011486:Protein C; C095381:factor V Leiden; D005165:Factor V