Factor V leiden homozygosity, dyspnea, and reduced pulmonary function.
BACKGROUND
Factor V Leiden homozygosity predisposes patients to deep venous thrombosis and major pulmonary thromboembolism. Consequently, factor V Leiden homozygosity could, via unrecognized repeated minor pulmonary thromboemboli, cause chronic pulmonary disease. We tested the hypothesis that factor V Leiden homozygosity is associated with pulmonary symptoms and signs.


METHODS
We studied a general population sample of 9253 individuals from the Copenhagen City Heart Study who were examined in 1991-1994. Of these, 6475 participants were also examined in 1976-1978 and/or 1981-1983. End points were dyspnea and lung function.


RESULTS
Among 20 factor V Leiden homozygotes, a mean +/- SD of 32% +/- 11% had severe dyspnea compared with 6% +/- 0.3% of 8534 noncarriers (chi(2) test; P<.001). The corresponding adjusted odds ratio for severe dyspnea was 5.4 (95% confidence interval, 1.9-15.7). During follow-up, forced expiratory volume in 1 second and forced vital capacity were 5% to 10% lower in homozygotes vs noncarriers (analysis of variance; P = .003 and P = .03). The annual mean +/- SD loss of forced expiratory volume in 1 second and forced vital capacity was 39 +/- 8 mL/y and 35 +/- 8 mL/y in homozygotes vs 21 +/- 10 mL/y and 15 +/- 10 mL/y in noncarriers (t test; P = .03 and P = .04), respectively. Factor V Leiden heterozygosity (n = 699) did not influence pulmonary symptoms and signs.


CONCLUSIONS
We demonstrate a previously unrecognized clinical presentation of factor V Leiden homozygosity with severe dyspnea and decreased pulmonary function.
Juul
Klaus
K
Department of Clinical Biochemistry, Herlev University Hospital, Herlev, Denmark.
Tybjaerg-Hansen
Anne
A
Mortensen
Jann
J
Lange
Peter
P
Vestbo
Jørgen
J
Nordestgaard
Børge G
BG
D000328:Adult; D000368:Aged; D004417:Dyspnea / Q000209:etiology; D005165:Factor V / Q000235:genetics*; D005260:Female; D006720:Homozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011655:Pulmonary Embolism / Q000175:diagnosis / Q000209:etiology / Q000235:genetics*; D012129:Respiratory Function Tests; D020246:Venous Thrombosis / Q000150:complications / Q000235:genetics*
C095381:factor V Leiden; D005165:Factor V