New-Onset Anemia Linked To Higher Cancer Risk And Mortality, Study Finds

A population-based study in Stockholm found that 6.2% of men and 2.8% of women with newly detected anemia developed cancer within 18 months. Researchers said the highest cancer risk occurred within three months of anemia diagnosis, with certain inflammatory anemia types linked to significantly increased cancer incidence.

The study, conducted by researchers at Karolinska Institutet in Stockholm and published in BMJ Oncology, followed nearly 190,000 adults over 18 years old who were newly diagnosed with anemia between 2011 and 2021. These individuals were matched by age and sex with an equal number of cancer-free controls, according to lead researcher Elinor Nemlander of the Department of Neurobiology, Care Sciences and Society. The findings showed that 6.2% of men and 2.8% of women with new-onset anemia were diagnosed with cancer within 18 months, compared with 1.1% of women without anemia.

“Women with anemia of inflammation—defined by ferritin levels above 100 ng/mL combined with elevated C-reactive protein (CRP)—had a 15.3% cancer diagnosis rate within 12 months.”

The risk of cancer was highest within the first three months after anemia detection but remained elevated throughout the entire follow-up period, Nemlander said. The study also found that mortality rates were higher among those with anemia than their matched counterparts without anemia during the 18-month observation window. “The increased risk persists later during follow-up as well,” Nemlander noted, describing anemia as a “strong and sustained risk marker” for both cancer incidence and all-cause mortality.

Subgroup analyses identified specific anemia types associated with markedly increased cancer risk. Women with anemia of inflammation—defined by ferritin levels above 100 ng/mL combined with elevated C-reactive protein (CRP)—had a 15.3% cancer diagnosis rate within 12 months. Men with combined inflammatory iron deficiency anemia, characterized by ferritin below 100 ng/mL and increased CRP, showed an even higher 19.3% cancer diagnosis rate in the same period. Overall, 7.9% of men and 5.2% of women with new-onset anemia received a cancer diagnosis within 12 months across the general cohort.

These inflammatory anemia types were linked to a 10- to 30-fold increase in cancer incidence compared with the general population, with approximately one in six individuals affected receiving a cancer diagnosis within a year, the study reported. Red blood cell size also emerged as a significant predictor of cancer risk and type. Individuals with microcytosis—small red blood cells as measured by mean corpuscular volume (MCV)—had particularly elevated risks for gastrointestinal and hematopoietic cancers. Conversely, macrocytosis, or enlarged red blood cells, was more strongly associated with increased mortality but not with cancer risk to the same extent.

The researchers concluded that anemia detected in routine healthcare settings is likely a sign of underlying disease rather than a standalone condition. They emphasized the importance of recognizing new-onset anemia as a potential marker for cancer, highlighting that the interval between first symptoms and cancer diagnosis can critically affect patient prognosis. Nemlander and colleagues called for increased awareness and improved clinical pathways for managing anemia in general practice to facilitate timely cancer detection.

The Stockholm Early Detection of Cancer Study, also known as STEADY-CAN, utilized comprehensive register data covering almost the entire adult population of Stockholm County. Its findings align with several international studies, including a 2022 Danish registry analysis, a 2015 Taiwanese investigation of iron deficiency anemia patients, and a 2021 South Korean study examining anemia defined by serum hemoglobin levels. These independent studies have similarly reported an association between new-onset anemia and elevated cancer risk.

Karolinska Institutet officials stated that the research may help guide clinical follow-up of patients with anemia in routine care. The study’s extensive population-based design and corroboration by international data provide robust evidence of the link between anemia and subsequent cancer diagnosis. Further research is needed to refine diagnostic and management strategies for anemia detected outside specialized oncology settings.