Body weight, diet may be risk factors for non-Hodgkin lymphoma

"The causes of non-Hodgkin lymphoma (NHL) are poorly understood, and unfortunately, we don't know very much about specific ways to prevent or lower the risk for this disease," said Kimberly Bertrand, Sc.D., research fellow in the department of epidemiology at the Harvard School of Public Health.

In previous analyses of the Nurses' Health Study at 14 years of follow-up, lead researcher Shumin Zhang, M.D., Sc.D., and colleagues reported positive associations with NHL for trans fat intake and inverse associations for vegetable intake. To expand those findings, Bertrand and colleagues evaluated the association of obesity, specific types of dietary fats, and fruits and vegetables with risk for NHL.

Researchers analyzed questionnaire responses from 47,541 men followed for 22 years in the Health Professionals' Follow-Up Study and 91,227 women followed for 28 years in the Nurses' Health Study. Among the women, researchers confirmed 966 incident diagnoses of NHL through 2008, and among the men, they confirmed 566 cases through 2006.

"In analyses that controlled for age, race and other factors, we found that obesity in young adulthood (ages 18 to 21 years) was associated with risk for NHL later in life," Bertrand said. "Men who were obese (body mass index [BMI] equal to or greater than 30) [in young adulthood] had a 64 percent higher risk for NHL compared with men who were lean, while obese women had a 19 percent higher risk."

Current BMI was also associated with risk for NHL in men but not in women. Although total and specific dietary fats were not associated with NHL risk, findings also suggested that women who consumed the highest amounts of trans fat in their diets had a nonstatistically significant increased risk for NHL overall. "We observed that women who consumed at least four servings of vegetables per day, compared with those who consumed fewer than two servings per day, had a 16 percent lower risk for developing NHL," Bertrand said.

"The results from this study, if confirmed in other studies, suggest that body weight and dietary choices may be potentially modifiable risk factors for NHL," she said. Bertrand and colleagues also plan to investigate associations of obesity and dietary factors with common subtypes of NHL, to evaluate biomarkers of fatty acids related to NHL risk to obtain more information on the possible biological mechanism for these associations, and to investigate other dietary factors including red meat consumption and antioxidants.

The study was supported by the American Cancer Society with funds to senior researcher, Brenda Birmann, M.Sc., Sc.D. (RSG-11-020-01-CNE), and by the National Institutes of Health (CA055075 and CA87969). Bertrand was supported by a training grant from the National Cancer Institute (R25 CA098566).