These results were published in the International Journal of Cancer.
Myeloproliferative neoplasms (MPN) are a related group of blood cancers. In these disorders, the bone marrow cells that produce blood cells develop and function abnormally. The three main types of MPN are polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). In addition to developing on its own, myelofibrosis may also develop as a result of ET or PMF.
The causes of MPN remain poorly understood. Family history increases risk, but is not something that people can change. If modifiable risk factors are identified, it could provide clues to how these diseases develop, and would also provide people with steps that they could take to reduce their risk. Factors such as regular physical activity and maintenance of a healthy body weight reduce the risk of several types of cancer, but there is little information about how these factors affect risk of MPN.
To assess lifestyle factors, medical history, and risk of MPN, researchers evaluated information from the Iowa Women’s Health Study. The study enrolled 27,370 women who between the ages of 55 and 69 at the start of the study. Women have now been followed for a median of 11 years. During that time, 257 cases of MPN (172 cases of ET, 64 cases of PV, and 21 cases of myelofibrosis) were diagnosed among study participants. Because there were so few cases of myelofibrosis, results were presented for ET and PV only.
- Current smoking was associated with an almost three-fold increase in the risk of PV, but did not appear to affect the risk of ET.
- Factors that increased the risk of ET included being overweight and having a history of adult-onset diabetes. Factors that reduced the risk of ET were regular physical activity and regular use of aspirin.
These results suggest that behaviors that reduce the risk of other types of cancer (avoiding tobacco smoke, engaging in regular physical activity, and maintaining a healthy body weight) may also reduce the risk of MPN. Furthermore, the fact that risk factors differed between PV and ET suggest that these two types of MPN may develop in different ways.
Reference: Leal AD, Thompson CA, Wang AH et al. Anthropometric, medical history and lifestyle risk factors for myeloproliferative neoplasms in The Iowa Women’s Health Study Cohort. International Journal of Cancer. Early online publication September 30, 2013.