Western Diet Linked With CLL

People who adhered to a Western dietary pattern were more likely to have chronic lymphocytic leukemia (CLL), according to data from the MCC-Spain case-control study published in Haematologica.

According to Marta Solans, of the Epidemiology Unit and Girona Cancer Registry at the Catalan Institute of Oncology in Girona, Spain, and colleagues, evidence suggests that some cases of CLL could be prevented by modifying dietary habits.

Diet has been identified as a modifiable risk factor for several cancers, but evidence linking diet and CLL is limited. To investigate a connection between diet and CLL, Solans and colleagues used data from the MCC-Spain study, which was initiated to evaluate influence of environmental exposures with genetic factors in CLL and other cancers.

“CLL is the most common leukemia in Western countries, while its incidence is much lower in Eastern countries, where it accounts for only 1% to 3% of NHL in most series,” the researchers wrote. “While genetic backgrounds may be responsible for part of the differences in the CLL incidence, some studies have suggested that environmental factors also play an important role.”

For the study, the researchers looked at CLL and a possible association with three diet types, Western, Prudent, and Mediterranean. A Western diet pattern was defined by a high intake of high-fat dairy products, processed meat, refined grains, sweets, caloric drinks, convenience food, and sauces. A Prudent diet was defined by a high intake of low-fat dairy products, vegetables, fruits, whole grains, and juices. A Mediterranean diet was defined by a high intake of fish, vegetables, legumes, boiled potatoes, fruits, olives, and vegetable oil.

The study included 369 patients with CLL and 1,605 controls taken from the MCC-Spain study between 2010 and 2013. The study collected data on socioeconomic factors, lifestyle, and personal/family medical history. Participants also completed a semi-quantitative Food Frequency Questionnaire.

Adjusting for potential confounders, the analysis showed that a Western dietary pattern was associated with increased risk for CLL (odds ratio for highest vs lowest intake = 1.63; 95% CI: 1.11–2.39). This association was independent of Rai stage. In contrast, no association was found between CLL risk and Prudent or Mediterranean diets.

According to the researchers, “this study provides, for the first time, evidence of an association between adherence to a Western dietary pattern and CLL.”

In addition, no association between CLL and sex, body mass index (BMI), energy intake, tobacco, physical activity, working on a farm, or family history of hematologic malignancy was found.

“A Western diet has been associated with obesity phenotypes, including a higher waist-to-hip ratio, which has in turn been recently linked to higher OR of CLL-particularly in women, in the MCC-Spain study,” the researchers wrote. “Despite the fact that CLL cases showed a higher waist-to-hip ratio than controls in our study, waist-to-hip ratio and BMI were not included as covariates in the final multiple-adjusted model, since they did not change risk estimates. Hence, an independent effect of the Western dietary pattern may be contributing to CLL lymphomagenesis, which seems plausible from a mechanistic point of view.”