A prospective study of obesity and cancer risk (Sweden).
OBJECTIVE
[corrected] We evaluated the relation between obesity and the risks for various forms of cancer.


METHODS
In a population-based cohort of 28,129 hospital patients (8165 men, 19,964 women) with any discharge diagnosis of obesity (9557 only diagnosis, 5266 primary, 13,306 secondary) during 1965-1993, cancer incidence was ascertained through 1993 by record linkage to the nationwide Swedish Cancer Registry. Cancer risk was estimated using the standardized incidence ratio (SIR, with 95% confidence interval), which is the ratio of the observed number of cancers to that expected.


RESULTS
Overall, a 33% excess incidence of cancer was seen in obese persons, 25% in men and 37% in women. Significant risk elevations were observed for cancers of the small intestine (SIR = 2.8; 95% CI 1.6-4.5), colon (1.3; 1.1-1.5), gallbladder (1.6; 1.1-2.3), pancreas (1.5; 1.1-1.9), larynx (2.1; 1.1-3.5), renal parenchyma (2.3; 1.8-2.8), bladder (1.2; 1.0-1.6), cervix uteri (1.4; 1.1-1.9), endometrium (2.9; 2.5-3.4), ovary (1.2; 1.1-1.5), brain (1.5; 1.2-1.9), and connective tissue (1.9; 1.1-3.0), and for lymphomas (1.4; 1.0-1.7), with higher risk observed for Hodgkin's disease only in men (3.3; 1.4-6.5) and for non-Hodgkin's lymphoma only in women (1.6; 1.2-2.1). The association of obesity with risk of breast, prostate and pancreas cancers was modified by age.


CONCLUSIONS
Obesity is associated with more forms of cancer than previously reported.
Wolk
A
A
Karolinska Institute, Department of Medical Epidemiology, Stockholm, Sweden. Alicja.Wolk@mep.ki.se
Gridley
G
G
Svensson
M
M
Nyrén
O
O
McLaughlin
J K
JK
Fraumeni
J F
JF
Adam
H O
HO
D000293:Adolescent; D000328:Adult; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D009765:Obesity / Q000150:complications*; D010351:Patient Discharge / Q000706:statistics & numerical data; D011159:Population Surveillance; D015995:Prevalence; D012042:Registries; D012307:Risk Factors; D017678:Sex Distribution; D013548:Sweden / Q000453:epidemiology