Obesity and risk of non-Hodgkin lymphoma (United States).

OBJECTIVE: Few studies have explored the potential association between body mass index (BMI) and non-Hodgkin lymphoma (NHL) according to histologic subtypes, or have evaluated BMI at different periods in the subject's life, and the results of these studies have been inconsistent.

SUBJECTS: A population-based, case-control study of 387 patients with NHL and 535 controls conducted in Nebraska between 1999 and 2002.

METHODS: Information on usual adult weight, weight at the ages 20-29, 40-49, and 60-69 years, height, physical activity, and other lifestyle factors was collected by telephone interview. A self-administered semi-quantitative food frequency questionnaire was used to collect dietary intake. Risk was estimated by odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for age, total energy intake, physical activity, and other confounding factors.

RESULTS: Higher adult BMI was associated with risk of NHL (OR=1.4; 95% CI=0.9-2.0) comparing the obese group (BMI >or= 30.0 kg/m(2)) with the normal weight group (BMI=18.5-24.9 kg/m(2)). The risk was higher for those who were class 2 obese (BMI >or= 35.0 kg/m(2), OR=1.7; 95% CI=1.0-2.9). The positive association was similar among men and women. An excess risk of NHL was associated with high BMI at ages 40-49 years (OR=1.6; 95% CI=1.0-2.5), and to a lesser extent, at ages 20-29 years (OR=1.4; 95% CI=0.8-2.5). Obesity at ages 40-49 years was also associated with a higher risk of small lymphocytic lymphoma (OR=4.5; 95% CI=1.5-13.3), diffuse large B-cell NHL (OR=1.8; 95% CI=0.9-3.9) and follicular NHL (OR=1.8; 95% CI=0.9-3.5).

CONCLUSION: Obesity is associated with risk of NHL overall. Obesity at ages 40-49 years is also associated with a higher risk of NHL overall, and particularly small lymphocytic, follicular, and diffuse large B-cell NHL.