Cigarette smoking and risk of non-Hodgkin's lymphoma--a population-based case-control study.
BACKGROUND
Epidemiologic evidence of an association between tobacco smoking and non-Hodgkin's lymphoma has been conflicting. This may reflect that non-Hodgkin's lymphoma comprises several distinct disease entities with different etiologies, as some studies have indicated an association between smoking and follicular lymphoma.


OBJECTIVE
To investigate the association between cigarette smoking and non-Hodgkin's lymphoma risk, overall and by subtype.


METHODS
As part of a nationwide Danish-Swedish population-based case-control study, we interviewed 3,055 incident non-Hodgkin's lymphoma patients and 3,187 population controls. All lymphomas were uniformly classified according to the WHO classification. We used unconditional logistic regression to estimate adjusted odds ratios (OR) and 95% confidence intervals (95% CI) for the association between cigarette smoking and risk of non-Hodgkin's lymphoma.


RESULTS
Cigarette smoking was not associated with the risk of non-Hodgkin's lymphoma overall (OR, 0.97; 95% CI, 0.87-1.08) nor with the major subgroups such as diffuse large B-cell lymphoma (OR, 0.94; 95% CI, 0.79-1.10), chronic lymphocytic leukemia (OR, 0.86; 95% CI, 0.72-1.02), or follicular lymphoma (OR, 1.03; 95% CI, 0.85-1.24). Female smokers were at a marginally increased risk of follicular lymphoma (OR, 1.41; 95% CI, 1.04-1.92). Men who had ever smoked had a significantly increased risk of T-cell lymphoma (OR, 1.67; 95% CI, 1.11-2.51). No dose-response association with cigarette smoking could be established for any lymphoma subgroup.


CONCLUSIONS
We found little evidence of an association between cigarette smoking and non-Hodgkin's lymphoma risk overall. Although increased risks of follicular lymphoma in female smokers and of T-cell lymphoma in male smokers were suggested, no dose-response relationship was observed, leaving limited support for causality.
Schöllkopf
Claudia
C
Department of Epidemiology Research, Statens Serum Institut, Artillerivej 5, 2300 Copenhagen, Denmark. CKO@SSI.dk
Smedby
Karin Ekström
KE
Hjalgrim
Henrik
H
Rostgaard
Klaus
K
Gadeberg
Ole
O
Roos
Göran
G
Porwit-Macdonald
Anna
A
Glimelius
Bengt
B
Adami
Hans-Olov
HO
Melbye
Mads
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003718:Denmark / Q000453:epidemiology; D004522:Educational Status; D005260:Female; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods*; D012306:Risk; D012907:Smoking / Q000009:adverse effects*; D013548:Sweden / Q000453:epidemiology