Abstract
PURPOSE: To evaluate the association of body mass index (BMI) and physical activity (PA) during adulthood and at the age of 18 years with risk of non-Hodgkin lymphoma (NHL). METHODS: We enrolled 950 newly diagnosed NHL patients and 1146 frequency-matched clinic-based controls. Height, weight, and PA (recent adult and at the age of 18 years) were self-reported. Odds ratios (ORs), 95% confidence intervals, and tests for trend were estimated using unconditional logistic regression adjusted for age, gender, and residence. RESULTS: BMI at the age of 18 years was associated with an increased NHL risk (OR, 1.38 for highest vs. lowest quartile; p-trend = .0012), which on stratified analysis was specific to females (OR, 1.90; p-trend = .00025). There was no association of adult BMI with NHL risk. Higher PA in adulthood (OR, 1.03; p-trend = .85) or at the age of 18 years (OR, 0.88; 95% confidence interval, 0.72-1.07) was not associated with risk, but there was an inverse association for adult PA that was specific to females (OR, 0.71; p-trend = .039). Only BMI at the age of 18 years remained significantly associated with NHL risk when modeled together with PA in adulthood or at the age of 18 years. There was little evidence for heterogeneity in these results for the common NHL subtypes. CONCLUSIONS: Early adult BMI may be of greatest relevance to NHL risk, particularly in females.