Liver and gallbladder cancer in immigrants to Sweden.
BACKGROUND
The changes of cancer incidence upon immigration can be used as an estimator of environmental influence on cancer risk. We studied site-specific liver and biliary cancers in first-generation immigrants to Sweden with an aim to search for aetiological clues and to find evidence for indigenous incidence rates.


METHODS
We used the nation-wide Swedish Family-Cancer Database to calculate standardised incidence ratios (SIRs) in immigrants compared to native Swedes.


RESULTS
A total of 1428 cancers were identified in immigrants whose median ages (years) at immigration were 27 for men and 26 for women and whose median diagnostic ages were 64 and 66, respectively. The highest SIRs of 6.7 for primary liver cancer were observed for men from East Asia and sub-Saharan Africa. Increased SIRs were recorded for male immigrants from previous Yugoslavia (1.78), Southern Europe (2.91), Turkey (2.15) and Asian Arab countries (2.89). For gallbladder cancer, only women from the Indian subcontinent (3.84) and Chile (2.34) had increased risk while some Northern European immigrants showed decreased risks.


CONCLUSIONS
Primary liver cancer was increased in immigrants from endemic regions of hepatitis B virus infection but also from large regions lacking cancer incidence data, North Africa, Asian Arab countries, Turkey and previous Yugoslavia; these are probably intermediary risk regions for this infection. The consideration of these regions as risk areas would justify active diagnostic and vaccination programs. The increase in gallbladder cancer in Chileans and Indians suggests that some persistent damage was inflicted before emigration, characterisation of which will be a challenge for aetiological studies.
Hemminki
Kari
K
Division of Molecular Genetic Epidemiology, German Cancer Research Centre (DKFZ), 69120 Heidelberg, Germany. k.hemminki@dkfz-heidelberg.de
Mousavi
Seyed Mohsen
SM
Brandt
Andreas
A
Ji
Jianguang
J
Sundquist
Jan
J
D000328:Adult; D000368:Aged; D054242:Emigrants and Immigrants / Q000706:statistics & numerical data*; D005260:Female; D005706:Gallbladder Neoplasms / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008113:Liver Neoplasms / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult