Epidemiology, fibrinogen, clot properties, and cardiovascular disease risk—an African perspective

A state of the art lecture titled "Epidemiology, fibrinogen, clot properties and cardiovascular disease risk: an African perspective" was presented at the International Society on Thrombosis and Haemostasis (ISTH) congress in 2025. Altered fibrin clot structure, characterized by tightly packed fibers, stiffer networks, and resistance to lysis, contributes to thrombosis. However, most of the available evidence comes from relatively small-sized observational, case-control studies or from animal models or <i>in vitro</i> studies. Much less is known regarding clot properties on population level. Epidemiological evidence may help determine lifestyle, demographic, and genetic factors as well as gene-environment interactions that can influence fibrinogen concentration and clot properties of a population. Most of the epidemiological evidence reported in this review comes from individuals from African descent. Similar to what has been observed in Europeans, we demonstrate that factors including obesity, dyslipidemia, inflammation, poor glycemic control, and aging-promoted prothrombotic clot properties, whereas higher high-density lipoprotein cholesterol and moderate alcohol intake were protective. Importantly, some of these factors had direct effects on clot properties, independent of fibrinogen concentration. Genetic analyses revealed distinct features in Africans compared with Europeans, including absence of common European haplotypes, novel variants, and reduced linkage disequilibrium, enabling the detection of unique gene-environment interactions in Africans. These gene-environment interactions not only influenced fibrinogen concentration but also modified clot properties and their responses to environmental and metabolic factors. Together, these findings emphasize the complexity of fibrinogen biology, the importance of functional clot properties in disease risk, and the need for population-specific studies to inform prevention strategies in Africa and globally. Finally, we summarize relevant new data on this topic presented during the 2025 ISTH Congress.