@article {693, title = {Protein C, antithrombin, and venous thromboembolism incidence: a prospective population-based study.}, journal = {Arterioscler Thromb Vasc Biol}, volume = {22}, year = {2002}, month = {2002 Jun 01}, pages = {1018-22}, abstract = {

Although deficiencies of protein C and antithrombin, 2 natural plasma anticoagulants, are known risk factors for venous thrombosis, population-based prospective incidence data on these associations are lacking. Venous thromboembolic events have been identified in adults in 2 longitudinal cohort studies, the Atherosclerosis Risk in Communities (ARIC) Study and the Cardiovascular Health Study (CHS). Incidence was examined in relation to prediagnostic plasma levels of protein C (ARIC Study only) and antithrombin. Over a mean of 8.1 years of follow-up, there were 130 incident venous thromboembolic events that were not due to cancer in the ARIC Study. The age-adjusted incidence was elevated 3.36-fold (95\% CI 1.24 to 9.11) in the 1.1\% of subjects with protein C values <2.0 mg/L compared with subjects with higher values. In contrast, in the ARIC Study and the CHS, there was no association between low plasma antithrombin and venous thromboembolism. In conclusion, in this population-based study, a low protein C, but not antithrombin, level has been determined to be associated with an increased incidence of venous thromboembolism. Attributable risk estimates suggest that low protein C levels account for approximately 2.5\% of venous thromboembolic events in the ARIC population.

}, keywords = {Adult, Aged, Aged, 80 and over, Antithrombins, Arteriosclerosis, Cohort Studies, Humans, Incidence, Longitudinal Studies, Middle Aged, Odds Ratio, Population Surveillance, Prospective Studies, Protein C, Protein C Deficiency, Pulmonary Embolism, Thromboembolism, Venous Thrombosis}, issn = {1524-4636}, doi = {10.1161/01.atv.0000017470.08363.ab}, author = {Folsom, Aaron R and Aleksic, Nena and Wang, Lu and Cushman, Mary and Wu, Kenneth K and White, Richard H} } @article {793, title = {Deep vein thrombosis and pulmonary embolism in two cohorts: the longitudinal investigation of thromboembolism etiology.}, journal = {Am J Med}, volume = {117}, year = {2004}, month = {2004 Jul 01}, pages = {19-25}, abstract = {

PURPOSE: To determine the incidence of deep vein thrombosis and pulmonary embolism in two cohorts representing regions of the United States.

METHODS: The sample comprised 21,680 participants of the Atherosclerosis Risk in Communities study and the Cardiovascular Health Study. Subjects were aged >/=45 years, resided in six communities, and were followed for 7.6 years. All hospitalizations were identified and thromboses were validated by chart review.

RESULTS: The age-standardized incidence of first-time venous thromboembolism was 1.92 per 1000 person-years. Rates were higher in men than women, and increased with age in both sexes. There was no antecedent trauma, surgery, immobilization, or diagnosis of cancer for 48\% (175/366) of events. The 28-day case-fatality rate was 11\% (29/265) after a first venous thromboembolism and 25\% (17/67) for cancer-associated thrombosis. The recurrence rate 2 years after a first venous thromboembolism was 7.7\% per year (95\% confidence interval [CI]: 4.5\% to 10.9\% per year). Cancer was the only factor independently associated with 28-day fatality (relative risk [RR] = 5.2; 95\% CI: 1.4 to 19.9) or recurrent thrombosis (RR = 9.2; 95\% CI: 2.0 to 41.7).

CONCLUSION: The incidence of venous thromboembolism in this cohort of middle- and older-aged subjects was similar to that observed in more geographically homogeneous samples. Half of cases were idiopathic. Short-term mortality and 2-year recurrence rates were appreciable, especially among subjects with cancer. Based on this study we estimate that 187,000 cases of first-time venous thromboembolism are diagnosed yearly in the United States among those aged 45 years or older.

}, keywords = {Aged, Case-Control Studies, Cohort Studies, Female, Follow-Up Studies, Humans, Incidence, Male, Middle Aged, Neoplasms, Population Surveillance, Pulmonary Embolism, Recurrence, Risk Factors, Survival Rate, Venous Thrombosis}, issn = {0002-9343}, doi = {10.1016/j.amjmed.2004.01.018}, author = {Cushman, Mary and Tsai, Albert W and White, Richard H and Heckbert, Susan R and Rosamond, Wayne D and Enright, Paul and Folsom, Aaron R} } @article {1175, title = {Reproductive history, hormone replacement, and incidence of venous thromboembolism: the Longitudinal Investigation of Thromboembolism Etiology.}, journal = {Br J Haematol}, volume = {149}, year = {2010}, month = {2010 May}, pages = {606-12}, abstract = {

Numerous studies have established that hormone replacement therapy increases the risk of venous thromboembolism (VTE), but an association of endogenous oestrogen exposure with the incidence of VTE is not fully established. Using a prospective design combining the Atherosclerosis Risk in Communities and the Cardiovascular Health Study cohort, we studied the 12-year risk of VTE in relation to hormone replacement therapy use, age at menopause, parity number, and type of menopause in 8236 post-menopausal women. There were no significant associations of age at menopause, parity number, or type of menopause with incidence of VTE. Women currently using hormone replacement had a 1.6-times higher multivariate-adjusted rate ratio (RR) of VTE compared with those without hormone use in the time-dependent model (RR=1.60, 95\% confidence interval [CI], 1.06-2.36; Population attributable fraction=6.7\%, 95\%CI, 1.0-10.3). When we excluded women with 1-year or more duration of hormone therapy at baseline, the association was stronger (RR=2.02, 95\%CI, 1.31-3.12). The multivariate-adjusted RRs of VTE for current users tended to be higher in those with idiopathic VTE (RR=2.40, 95\%CI, 1.40-4.12) than those with secondary VTE (RR=1.08, 95\%CI, 0.63-1.85). Hormone replacement therapy is associated with increased risk of VTE, but reproductive history markers of endogenous oestrogen exposure were not associated with VTE.

}, keywords = {Age Factors, Aged, Epidemiologic Methods, Estrogen Replacement Therapy, Female, Humans, Male, Middle Aged, Parity, Pregnancy, Reproductive History, United States, Venous Thromboembolism}, issn = {1365-2141}, doi = {10.1111/j.1365-2141.2010.08128.x}, author = {Ohira, Tetsuya and Folsom, Aaron R and Cushman, Mary and White, Richard H and Hannan, Peter J and Rosamond, Wayne D and Heckbert, Susan R} }