Thromb Haemost 2013; 110(06): 1164-1171
DOI: 10.1160/TH13-04-0320
Blood Coagulation, Fibrinolysis and Cellular Haemostasis
Schattauer GmbH

Age-and sex-specific seasonal variation of venous thromboembolism in patients with and without family history: a nationwide family study in Sweden

Bengt Zöller
1   Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
,
Xinjun Li
1   Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
,
Henrik Ohlsson
1   Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
,
Jan Sundquist
1   Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
2   Stanford Prevention Research Center, Stanford University School of Medicine, Palo Alto, California, USA
,
Kristina Sundquist
1   Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
2   Stanford Prevention Research Center, Stanford University School of Medicine, Palo Alto, California, USA
› Author Affiliations

Financial support: This work was supported by grants awarded to Dr Bengt Zöller by the Swedish Heart-Lung Foundation and Region Skåne (REGSKANE-124611); ALF funding awarded to Drs Bengt Zöller, Kristina Sundquist, and Jan Sundquist by Region Skåne; grants awarded to Drs Kristina and Jan Sundquist by the Swedish Research Council (K2009–70X-15428–05–3 and K2012–70X-15428–08–3); and grants awarded to Dr Jan Sundquist by the King Gustaf V and Queen Victoria’s Foundation of Freemasons.
Further Information

Publication History

Received: 18 April 2013

Accepted after major revision: 16 August 2013

Publication Date:
30 November 2017 (online)

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Summary

Seasonal variation in venous thromboembolism (VTE) risk in individuals with familial predisposition to VTE has not been explored. This nationwide study aimed to determine whether there are age- and sex-specific seasonal differences in risk of hospitalisation of VTE among individuals with and without a family history of VTE. The Swedish Multi-Generation Register was linked to Hospital Discharge Register data for the period 1964–2010. Seasonal variation in first VTE events in 1987–2010 for individuals with and without a family history of VTE (siblings or parents) was determined by several independent methods. Stratified analyses were performed according to age, sex, and VTE subtype (pulmonary embolism [PE] or deep venous thrombosis [DVT]). Seasonal variation in VTE incidence, mostly with a peak during the winter, was observed in both sexes in individuals with and without family history with overall peak-to-low ratios (PLRs) of 1.15 and 1.21, respectively. The peak day was December 25 and February 1 for those with and without a family history of VTE, respectively. Seasonal variation was strongest among individuals aged >50 years. Among individuals aged 0–25 years with a family history, the peak for VTE was in July (PLR = 1.20). Significant seasonal variation was observed for PE and DVT with the exception of DVT among those with a family history (PLR = 1.01). In conclusion, our data support the presence of a modest seasonal variation of VTE among individuals with and without a family history of VTE. However, young age and family history may modify and attenuate the effect of season on VTE.