Cancer diagnoses among older people with intellectual disability compared with the general population: a national register study.

BACKGROUND: Cancer occurrence among older people with intellectual disability (ID) is poorly documented, so we investigated the frequency and distribution of cancer in older people with ID compared with the general population. METHOD: People with ID who were ≥55years old and alive at the end of 2012 (n = 7936; ID cohort) were identified through a national register of people with ID who received social services in Sweden to optimise the individual's opportunity for good living conditions in daily life. An equally large reference cohort from the general population (gPop cohort) was matched by year of birth and sex. Cancer diagnoses registered in inpatient and outpatient specialist care were collected for 2002-2012 from the ID cohort and compared with diagnoses in the gPop cohort. RESULTS: A lower total cancer frequency was observed in the ID cohort, which contained 555 cancers, compared with 877 cancers in the gPop cohort [odds ratio (OR): 0.63; 95% confidence interval (CI): 0.57-0.70]. Women accounted for 60% of cancers in the ID cohort. Breast and gynaecological organ cancers had similar or slightly lower frequencies in the ID cohort than in the general population, with breast OR of 0.95, uterine corpus OR of 1.00 and ovary OR of 0.73. Surprisingly, cancer frequency of the digestive organs (OR: 0.67), including the colon (OR: 0.82), was lower than in the general population. Cancers of the prostate (OR: 0.25), urinary tract (OR: 0.42) and lung were less frequent than in the general population. CONCLUSIONS: Cancer was diagnosed less frequently in the ID cohort than in the gPop cohort. However, cancers of the breast and colon-rectum remain frequent in people with ID and therefore warrant prevention policies, monitoring and screening similar to those of the general population.