It has been unclear up to this point what part seasonal influences play in the etiology of acute myeloid leukemia (AML). An underlying seasonal etiology would be supported by evidence of seasonality in AML diagnosis. For a study, researchers used community-based data from a Spanish hospital discharge registry to examine possible seasonal and long-term patterns in AML diagnosis in the general population as well as in subgroups according to sex and age.

They conducted the largest analysis of AML diagnoses in Spain between 2004 and 2015, analyzing 26,472 cases. They discovered a long-term rising trend in the monthly incidence rates of AML, which increased by 0.4% yearly [95% CI, 0.2% -0.6%; P=0.0011] using multivariable Poisson generalized linear autoregressive moving average modeling. With a minimum average difference of 7% between January and February (95% CI, 2% -12%; P=0.0143) and a maximum average difference of 16% between January and November (95% CI, 11% -21%; P<0.0001) and August (95% CI, 10% -21%; P<0.0001), January showed the highest incidence rate of AML.

The seasonal impact persisted across subgroups based on sex and age. The discovery that AML diagnoses are seasonal clearly suggested that seasonal variables, such as infectious diseases or environmental triggers, have an impact on the onset and/or spread of illness, suggesting potential avenues for prevention.