Body mass index and risk of malignant lymphoma in Scandinavian men and women.
BACKGROUND
The incidence of non-Hodgkin lymphoma and prevalence of obesity are increasing globally. A suggested positive association between obesity and risk of non-Hodgkin lymphoma has prompted us to investigate the relationship between body mass index (BMI) and risk of malignant lymphoma subtypes in a population-based case-control study.


METHODS
Telephone interviews were conducted with 3055 case patients with non-Hodgkin lymphoma and 618 case patients with Hodgkin lymphoma diagnosed between October 1, 1999, and August 30, 2002, and 3187 population-based control subjects. The interviews assessed current height, normal adult weight, and other possible risk factors. Multivariable odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for risk of lymphoma were estimated by unconditional logistic regression. All statistical tests were two-sided.


RESULTS
BMI was not associated with risk of overall non-Hodgkin lymphoma or of Hodgkin lymphoma (for example, comparing the highly obese group [BMI > or =35.0 kg/m2] with the normal-weight group [BMI = 18.5-24.9 kg/m2], OR for risk of non-Hodgkin lymphoma = 0.9, 95% CI = 0.6 to 1.3; P(trend) across all categories of BMI = .27). BMI was also not associated with risk of any non-Hodgkin lymphoma subtype evaluated, although there was some evidence of a positive association with risk of diffuse large B-cell lymphoma (for example, comparing the highly obese group with the normal-weight group, OR for diffuse large B-cell lymphoma = 1.5, 95% CI = 0.9 to 2.4; P(trend) =.05).


CONCLUSIONS
Excess weight does not appear to be associated with an increased risk of malignant lymphoma in general, or with a risk of most major lymphoma subtypes. Hence, the growing incidence of obesity is unlikely to be an important contributor to the increasing incidence of non-Hodgkin lymphoma worldwide.
Chang
Ellen T
ET
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Box 281, SE-171 77 Stockholm, Sweden. ellen.chang@meb.ki.se
Hjalgrim
Henrik
H
Smedby
Karin Ekström
KE
Akerman
Måns
M
Tani
Edneia
E
Johnsen
Hans E
HE
Glimelius
Bengt
B
Adami
Hans-Olov
HO
Melbye
Mads
M
D000328:Adult; D000368:Aged; D015992:Body Mass Index; D016022:Case-Control Studies; D016001:Confidence Intervals; D015986:Confounding Factors, Epidemiologic; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D016393:Lymphoma, B-Cell / Q000453:epidemiology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000453:epidemiology; D008228:Lymphoma, Non-Hodgkin / Q000453:epidemiology* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D016017:Odds Ratio; D018570:Risk Assessment; D012307:Risk Factors; D015983:Selection Bias; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology