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Incidence of Cancer in Patients With Schizophrenia and Their First-Degree Relatives: A Population-Based Study in Sweden.

Ji, Jianguang LU orcid ; Sundquist, Kristina LU ; Ning, Yi ; Kendler, Kenneth S ; Sundquist, Jan LU and Chen, Xiangning (2013) In Schizophrenia Bulletin 39(3). p.527-536
Abstract
Context: Previous studies of the association between schizophrenia and cancer have produced conflicting results, probably because of the failure to control for confounding factors.



Objective: To test if the possible association between schizophrenia and cancer is genetic by investigating the incidence of cancer in patients with schizophrenia and their relatives.



Design: Retrospective cohort study with follow-up between 1965 and 2008. Estimated smoking rates were used to adjust the incidence rates of smoking-related cancers.



Participants: The entire Swedish population.Main outcome measures:Risk of overall cancer and 34 site-/type-specific cancers.Results:A total of 59 233 patients in... (More)
Context: Previous studies of the association between schizophrenia and cancer have produced conflicting results, probably because of the failure to control for confounding factors.



Objective: To test if the possible association between schizophrenia and cancer is genetic by investigating the incidence of cancer in patients with schizophrenia and their relatives.



Design: Retrospective cohort study with follow-up between 1965 and 2008. Estimated smoking rates were used to adjust the incidence rates of smoking-related cancers.



Participants: The entire Swedish population.Main outcome measures:Risk of overall cancer and 34 site-/type-specific cancers.Results:A total of 59 233 patients in Sweden with schizophrenia were identified, of whom 6137 developed cancer during the study period, giving a decreased standardized incidence ratio (SIR) of 0.79 (95% CI 0.77-0.81). The decrease was more pronounced (SIR 0.40, 95% CI 0.38-0.43) before the first diagnosis of schizophrenia. The overall risk was significantly reduced among their unaffected parents (SIR 0.96, 95% CI 0.94-0.98) and siblings (SIR 0.92, 95% CI 0.89-0.96). Sex-stratified analyses indicated different incidence rates between males and females, with female patients having higher cancer risks than the general population.



Conclusions: The significantly decreased incidences of cancers in patients diagnosed with schizophrenia and their unaffected relatives suggest that familiar/genetic factors contributing to schizophrenia may protect against the development of cancer, especially for those cancer sites observed in both settings. The increased risk of breast, cervical, and endometrial cancers after the first diagnosis of schizophrenia could be attributed to nongenetic factors such as antipsychotics administration, which may justify preventive medical screening. (Less)
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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Schizophrenia Bulletin
volume
39
issue
3
pages
527 - 536
publisher
Oxford University Press
external identifiers
  • wos:000318132200012
  • pmid:22522642
  • scopus:84875429911
  • pmid:22522642
ISSN
1745-1701
DOI
10.1093/schbul/sbs065
language
English
LU publication?
yes
id
fa49ffab-6223-414b-bf3c-7d66f9db083d (old id 2519233)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/22522642?dopt=Abstract
date added to LUP
2016-04-01 10:58:39
date last changed
2022-04-28 03:19:58
@article{fa49ffab-6223-414b-bf3c-7d66f9db083d,
  abstract     = {{Context: Previous studies of the association between schizophrenia and cancer have produced conflicting results, probably because of the failure to control for confounding factors.<br/><br>
<br/><br>
Objective: To test if the possible association between schizophrenia and cancer is genetic by investigating the incidence of cancer in patients with schizophrenia and their relatives.<br/><br>
<br/><br>
Design: Retrospective cohort study with follow-up between 1965 and 2008. Estimated smoking rates were used to adjust the incidence rates of smoking-related cancers.<br/><br>
<br/><br>
Participants: The entire Swedish population.Main outcome measures:Risk of overall cancer and 34 site-/type-specific cancers.Results:A total of 59 233 patients in Sweden with schizophrenia were identified, of whom 6137 developed cancer during the study period, giving a decreased standardized incidence ratio (SIR) of 0.79 (95% CI 0.77-0.81). The decrease was more pronounced (SIR 0.40, 95% CI 0.38-0.43) before the first diagnosis of schizophrenia. The overall risk was significantly reduced among their unaffected parents (SIR 0.96, 95% CI 0.94-0.98) and siblings (SIR 0.92, 95% CI 0.89-0.96). Sex-stratified analyses indicated different incidence rates between males and females, with female patients having higher cancer risks than the general population.<br/><br>
<br/><br>
Conclusions: The significantly decreased incidences of cancers in patients diagnosed with schizophrenia and their unaffected relatives suggest that familiar/genetic factors contributing to schizophrenia may protect against the development of cancer, especially for those cancer sites observed in both settings. The increased risk of breast, cervical, and endometrial cancers after the first diagnosis of schizophrenia could be attributed to nongenetic factors such as antipsychotics administration, which may justify preventive medical screening.}},
  author       = {{Ji, Jianguang and Sundquist, Kristina and Ning, Yi and Kendler, Kenneth S and Sundquist, Jan and Chen, Xiangning}},
  issn         = {{1745-1701}},
  language     = {{eng}},
  number       = {{3}},
  pages        = {{527--536}},
  publisher    = {{Oxford University Press}},
  series       = {{Schizophrenia Bulletin}},
  title        = {{Incidence of Cancer in Patients With Schizophrenia and Their First-Degree Relatives: A Population-Based Study in Sweden.}},
  url          = {{http://dx.doi.org/10.1093/schbul/sbs065}},
  doi          = {{10.1093/schbul/sbs065}},
  volume       = {{39}},
  year         = {{2013}},
}