Nested case-control study design. Flowchart depicting the nested case-control study design with a selection of cases with monocytosis and control subjects from the entire evaluable Lifelines cohort (n = 144 676). *Monocytosis was defined in accordance with WHO criteria for monocytosis associated with CMML: PB monocyte counts ≥1 × 10⁹/L and ≥10% of WBC. NGS, next-generation sequencing.