Platelet count is associated with cardiovascular disease, cancer and mortality: A population-based cohort study

•Low platelet count is associated with cancer in the general population.•High platelet count is associated with cardiovascular disease.•U-shaped relationship exists between platelet count and mortality.•Mortality corresponds to sex-specific reference range.

IntroductionPlatelet count is used to determine bleeding risk and monitoring thrombopoiesis. While abnormal platelet counts are associated with mortality and morbidity, it is unclear whether it also apply to platelet counts within reference range. We investigated the relationship between platelet count (100-450 × 109/L) and mortality, development of future cardiovascular disease (myocardial infarction, ischaemic stroke, or peripheral vascular disease), venous thromboembolism, bleeding or cancer in the general population.Material and methodsWe conducted a register-based cohort study of 21,252 adults (≥ 20 years) from the Danish General Suburban Population Study (GESUS). Laboratory results from GESUS were linked to information from national registers regarding morbidity and death. Cox proportional hazard regression was conducted with adjustment for age, sex, smoking status, haemoglobin, leukocyte count, C-reactive protein and Charlson comorbidity index.ResultsWe found a U-shaped relationship between mortality and platelet count. Mortality was significantly increased for platelet count < 175 × 109/L or > 300 × 109/L. When categorizing platelet count using the interval 201-250 × 109/L as reference group, platelet count 301-450 × 109/L was associated with mortality, adjusted hazard ratio (HR) = 1.42(95% CI 1.06-1.90) and cardiovascular disease, adjusted HR = 1.32 (95% CI 1.03-1.69). Platelet count 100-200 × 109/L was associated with future cancer, adjusted HR = 1.28(95% CI 1.05-1.57), but not with future bleeding or venous thromboembolism.ConclusionsPlatelet count is associated with mortality, future cardiovascular disease, and future cancer.