Seasonal variability of acute deep vein thrombosis onset

Objective To investigate the seasonal variability of the onset of acute deep vein thrombosis(DVT).Methods The clinical manifestations in 774 DVT patients during January 2008 to December 2012 were collected and circular distribution statistics was used to identify seasonal variability.Results The total sample had the significant seasonal variability (P ＜ 0.01):DVT was most frequent in winter while less frequent in summer and the peak day was January 1.Female subgroup has significant seasonal variability (P ＜0.01):on peak in winter and at trough in summer while male subgroup has no significant seasonal variability (P ＜ 0.01).Different age subgroups (＜ 40 years,40-69 years,＜70 years)have significant seasonal variability(P ＜ 0.05,P ＜ 0.01,P ＜ 0.01).DVT was most common in December and less frequent in August.Left lower limb subgroup and both lower limb subgroup has significant seasonal variability (P ＜ 0.01,P ＜ 0.01),on peak in December-January.Immobilization subgroup also has significant seasonal variability (P ＜ 0.001):frequent in winter,January 1 is on the peak.Conclusions DVT has significant seasonal variability in onset:it is most frequently seen in winter while less frequent in summer.Some subgroups (female,＜70 years and immobilization) have the most significant seasonal variability in onset. Key words: Venous thrombosis ;  Epidemiologic studies ;  Regular Season;  Circular distribution statistics