Cancer incidence among people with intellectual disability.
People with ID carry normal total cancer risk but higher rates of thyroid, testicular, brain, and gallbladder cancers—screen these sites and watch for late-stage skin tumors.
01Research in Context
What this study did
Simpson et al. (2001) counted every new cancer case in people with intellectual disability across an entire country. They used national health records to compare cancer rates with the general population.
The study looked at all cancer sites. It asked: Do people with ID get more cancer, less cancer, or the same?
What they found
Total cancer risk was about average. But four cancers showed up far more often: gallbladder, thyroid, brain, and testicular.
Three cancers showed up less often: prostate, urinary tract, and lung. The pattern was clear enough to guide future screening plans.
How this fits with other research
Sandberg et al. (2026) saw the same overall rate 25 years later. They added a twist: recorded cancer looks lower because screening is spotty, not because true risk is low. The two studies agree on biology but differ on why the numbers look flat.
Mammarella et al. (2022) zoomed in on melanoma. They found later-stage tumors in adults with ID. This extends K et al.'s call for proactive screening to skin checks.
Richman et al. (2001) and Williams et al. (2002) help explain the high gallbladder and stomach signal. Up to 90 % of institutionalized adults carry H. pylori, a germ linked to these cancers. The newer papers add a likely cause to the original count.
Why it matters
You can build a simple cancer-watch list for clients with ID. Add routine thyroid, testicular, and skin checks. Ask the doctor about gallbladder pain and consider H. pylori testing for those with long institutional stays. Skip the PSA hype unless other risk factors exist. These small tweaks catch the cancers that actually hit this population harder.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Add a 30-second thyroid and testicular check to your monthly health screen, and prompt the doctor if any swelling lasts two weeks.
02At a glance
03Original abstract
The aim of the present study was to address the unresolved question of the risk of neoplasms among people with intellectual disability (ID). A total of 2173 individuals with ID from a large, representative, nation-wide population study conducted in Finland in 1962 were followed-up for cancer incidence between 1967 and 1997. Standardized incidence ratios (SIRs) were defined as ratios of observed to expected numbers of cancer cases. Expected rates were based on national incidence rates. The observed number of cancers in the cohort (173) was close to what was expected [SIR = 0.9, 95% confidence interval (95% CI) = 0.8-1.0]. There was a significantly reduced risk of cancers of the prostate (SIR = 0.2, 95% CI = 0.0-0.5), urinary tract (SIR = 0.3, 95% CI = 0.1-0.7) and lung (SIR = 0.6, 95% CI = 0.4-1.0). The risk was increased in cancers of the gallbladder (SIR = 2.8, 95% CI = 1.1-5.8) and thyroid gland (SIR = 2.1, 95% CI = 1.0-4.8). The risks of lung and gallbladder cancer were lowest and highest, respectively, in those subjects with profound and severe ID, a group who also had significantly elevated SIRs for brain cancer (SIR = 3.46, 95% CI = 1.5-14.4) and testicular cancer (SIR = 9.9, 95% CI = 1.2-35.6). The incidence of cancer among people with ID was comparable with the general population, despite their low prevalence of smoking and apparently decreased diagnostic screening activity. Nevertheless, a few types of cancer carry a higher risk in the population with ID, possibly because of conditions typical among this group, such as gallstones or oesophageal reflux.
Journal of intellectual disability research : JIDR, 2001 · doi:10.1046/j.1365-2788.2001.00322.x