Body mass index and risk of Hodgkin's lymphoma: Insights from a Norwegian cohort study.

BACKGROUND

Several studies have reported positive associations between higher body mass index (BMI) and risk of Hodgkin's lymphoma. However, the evidence is not entirely consistent. We investigated the association between BMI and Hodgkin's lymphoma in a large Norwegian cohort with up to 50 years follow-up.

METHODS

The analytical dataset included 1723,692 men and women aged 16-75 years at baseline in 1963-1975. Multivariable Cox regression analyses were used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) for the associations between BMI and Hodgkin's lymphoma incidence.

RESULTS

During 56.1 million person-years of follow-up, 1608 incident Hodgkin's lymphoma cases occurred. Compared to individuals with BMI 18.5-< 25, the HRs (95 % CIs) for those with a BMI of 15-< 18.5, 25-< 30, and ≥ 30 were 0.87 (0.59-1.27), 1.05 (0.94-1.18), and 1.61 (1.35-1.91), respectively, and 1.57 (1.30-1.90) and 1.80 (1.24-2.62) for obesity grade 1 and grade 2, respectively. A positive association was also observed per 5 kg/m increment with a HR (95 % CI) of 1.16 (1.08-1.24) overall, 1.20 (1.09-1.31) in women, and 1.08 (0.96-1.20) in men. Positive associations were also observed between obesity vs. normal weight in early adulthood (age 16-29 years) and Hodgkin's lymphoma (HR, 95 % CIs: 1.89, 1.10-3.22, p<0.0001, n = 489 cases) and between obesity and early-onset (age <50 years at diagnosis) disease (HR, 95 % CIs: 1.67, 1.01-2.78, p<0.0001, n = 393 cases).

CONCLUSION

The positive associations observed between higher BMI overall and in young adulthood and Hodgkin's lymphoma and between BMI and early-onset disease emphasize the potential role of adiposity in development of this malignancy.