Published in the American Journal of Epidemiology, the study also showed that diets high in dietary fiber -- tomatoes, broccoli, mixed lettuce salad with vegetables, cauliflower, etc.-- were associated with a reduced risk of NHL.
"An association between dietary intake and NHL is biologically plausible because diets high in protein and fat may lead to altered immunity, resulting in increased risk of NHL," said principal investigator Tongzhang Zheng, M.D., associate professor of epidemiology and environmental health at Yale School of Medicine. "The antioxidants found in vegetables and fruits may result in reduced risk of about 40 percent."
The study was conducted between 1995 and 2001 on 601 Connecticut women between the ages of 21 and 84 diagnosed with varying subtypes of NHL. Using a Food Frequency Questionnaire (FFQ) developed by the Fred Hutchinson Cancer Research Center, each participant was asked to characterize her usual diet in the year prior to being interviewed. The FFQ collects consumption frequency and portion size data for approximately 120 foods and beverages and is periodically updated to reflect U.S. food consumption patterns and major market changes. After completion, the FFQ was sent to the Fred Hutchinson Cancer Research Center for calculating average daily nutrient intakes. The study included a control group of 717 women.
"So far, risk of NHL associated with animal protein and fat intakes has only been investigated in American women, in three studies," said Zheng. "If the association could also be demonstrated in American men, it would provide important information towards understanding the cause of NHL."
Other authors on the study included Theodore R. Holford, Yawei Zhang, M.D., Brian Leaderer, Stuart Flynn, M.D., Geovanni Tallini, M.D. and Patricia Owens of Yale; Sheila Hoar Zahm of the National Cancer Institute; and Peter Boyle of Europe Institute of Oncology, Milan, Italy and Qing Lan, M.D. and Nathaniel Rothman, M.D., of the National Cancer Institute.
The National Cancer Institute funded the study. Citation: American Journal of Epidemiology, March 1, 2004; Volume 159, Issue 5 454-466