Objective: During the last 50 years there have been significant improvements in life expectancy among people with intellectual disability (ID), and so their incidence of age-associated diseases, such as cancer, is rising. The aim of this study was to compare the rate of cancer in people with ID with that found in the general population.
Methods: Information on 9409 individuals registered with the Disability Services Commission of Western Australia was linked to the State Cancer Registry, with 200 cases of cancer detected over 156,729 person-years. Standardised incidence ratios (SIRs) and 95% confidence intervals were calculated for both sexes separately by 5-year age groups for the period 1982-2001. The same procedures were adopted in the estimation of SIRs for specific types of cancers.
Results: The age-standardised incidence of all cancers in people with ID was not significantly different from the general population. However, males with ID were observed to have a significantly increased risk of leukaemia, brain and stomach cancers, and a reduced risk of prostate cancer, while leukaemia, corpus uteri and colorectal cancers were significantly higher in females.
Conclusions: Health practitioners need to be aware that with improvements in life expectancy the incidence of cancer in people with ID is likely to rise. More proactive health promotion campaigns may be needed for people with ID, who are likely to be poor users of screening services and whose symptoms may not be reported until they are in more advanced, less treatable stages of disease.