The Influence of Meteorological Variables on the Occurrence of Deep Venous Thrombosis.

BACKGROUND: Deep venous thrombosis (DVT) risk factors are well-established, yet meteorological influences remain debated, especially in North Africa. AIM: We assessed associations between meteorological factors, seasonal patterns, and DVT incidence in central Tunisia. METHODS: This monocentric cross-sectional study included 211 patients with 217 ultrasound-confirmed DVT episodes (2009-2021) residing in Sousse or Kairouan. Meteorological data were obtained from national sources. Multivariate analysis adjusted for residence and the COVID-19 period (2020-2021). RESULTS: Idiopathic DVT accounted for 53.9% of cases, peaking in winter (p=0.010), while cancer-associated DVT peaked in summer (p=0.017). No significant differences emerged between Sousse and Kairouan residents. Months with DVT exhibited higher cloud cover (19.2% vs. 16.89%, p=0.032) and lower atmospheric pressure (1018.36 vs. 1020.13 hPa, p=0.042). Multivariate analysis confirmed increased cloud cover (aOR=1.04, p=0.046) and lower pressure (aOR=0.88, p=0.047) as independent risk factors. COVID-19 period incidence was higher (IRR=1.46, p=0.032) but did not alter meteorological associations. Summer 2021 heatwave analysis confirmed result stability. CONCLUSION: Lower atmospheric pressure and greater cloud cover independently increase DVT risk in central Tunisia. Seasonal patterns vary by etiology. Despite pandemic-related incidence increases, meteorological associations remained robust, suggesting weather modulates thrombotic risk.