Researchers have found that obese persons are at higher risk as compared to lean person to develop multiple myeloma.
Multiple myeloma or Kahler's disease is a type of cancer of plasma cells which are immune system cells in bone marrow that produce antibodies. Its prognosis, despite therapy, is generally poor, and treatment may involve chemotherapy and stem cell transplant.
The joint study was conducted by a team of researchers led by Brenda M. Birmann at Brigham and Women's Hospital, Harvard Medical School, and Harvard School of Public Health.
As part of the study, researchers analysed data of over 100,000 participants in the on-going Nurses' Health Study and Health Professionals Follow-up Study.
The Brigham and Women's Hospital-based Nurses' Health Study followed the health of female registered nurses since 1976, and the Health Professionals Follow-up Study, based at Harvard School of Public Health, followed males from several health professions since 1986.
The studies recorded height, weight and physical activity for each person enrolled, as well as diet, medications, smoking habits and other health behaviours, which was updated every two to four years.
Researchers found that of the 136,623 participants, who qualified for the study protocol, 215 cases had multiple myeloma.
The association between BMI and multiple myeloma was strongest among men with a BMI of 30 or more. The effect was less pronounced among overweight or obese women, yet those women also had an increased risk.
Researchers explained that previous research has identified possible biological links between obesity and multiple myeloma. For example, adipocytes, cells found in fat tissue, produce a cell signal, called interleukin-6 (IL-6), which promotes the immune system's inflammation response. In obese people, this can cause an overproduction of IL-6, which in turn creates a cellular environment that sustains multiple myeloma.
"The IL-6 chemical pathway is one possible way obesity could influence the risk of developing diseases like cancer or cardiovascular disease, but the answer might also lie in other relationships between obesity and cancer," Birmann said.
The findings of the study were published in the July issue of Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.