Comparative analysis of the associations between solar activity and trends in the incidence of haemoblastoses in Russia, the USA and Canada

Background. Identification of the links between hemoblastoses and environmental factors is necessary for the development of preventive measures. 
Aim. Comparative analysis of the link between hemoblastosis trends in Russia, the USA and Canada and solar activity. 
Material and methods. The open data on the incidence of hemoblastoses in Canada (19832012), the USA (19982012) and Russia (19932018) was used. To estimate solar activity, the average annual number of sunspots (Wolff numbers) was taken. The relationship between the frequency of hemoblastoses and solar activity was studied using the Pearson correlation analysis in 11 iterations (lag 010 years). The results obtained are compared with the data of an earlier study on Russia. 
Results. In Canada, an association with Wolf numbers was found in the frequency of Hodgkin's lymphoma in men (r=0.431, p=0.017, lag 2 years), multiple myeloma in women (r=0.542, p=0.037, lag 1 year), non-Hodgkin's lymphomas in men (r =0.538, p=0.038, lag 5 years) and women (r=0.750, p=0.001, lag 5 years), leukemia in men (r=0.707, p=0022, lag 7 years) and women (r=0.817, p=0.004, lag 7 years). In the United States, a relationship with solar activity was established for fluctuations in the incidence of Hodgkin's lymphoma in men (r=0.577, p=0.050, lag 5 years) and women (r=0.641, p=0.025, lag 5 years), non-Hodgkin's lymphomas in men (r=0.809, p 0.001, lag 3 years) and women (r=0.844, p 0.001, lag 2 years), leukemia in men (r=0.619, p=0.032, lag 1 year). In the Russian population, a relationship between solar activity and the frequency of all forms of hemoblastoses, was previously revealed. Fluctuations in the frequency of leukemia and non-Hodgkin's lymphomas in the populations of Russia, the USA and Canada have a strong positive relationship with solar activity. The strength of this association in Hodgkin's lymphoma and multiple myeloma ranges from moderate to significant. In all the countries studied, an increase in the incidence of multiple myeloma and leukemia was found, and an increase in the incidence of non-Hodgkin's lymphomas was found in Russia and Canada. The trend in the incidence of Hodgkin's lymphoma in Russia and Canada has a significant downward trend. 
Conclusion. Trends in hemoblastoses in Russia, the USA and Canada are strongly related to solar activity.