Association of inflammatory bowel disease in first-degree relatives with risk of colorectal cancer : A nationwide case-control study in Sweden

• This study aims to assess the association between inflammatory bowel disease (IBD) history in first-degree relatives (FDRs) and colorectal cancer (CRC) risk. We conducted a nationwide case-control study in Sweden among 69,659 CRC cases and 343,032 non-CRC controls matched on age, sex, birth year, and residence county. Through linkage of multi-generation register and the nationwide ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) cohort, we ascertained IBD diagnoses among parents, full siblings, and offspring of the index individuals. Odds ratios (ORs) of CRC associated with IBD family history were calculated using conditional logistic regression. 2.2% of both CRC cases (1,566/69,659) and controls (7,676/343,027) had ≥1 FDR with IBD history. After adjusting for family history of CRC, we observed no increased risk of CRC in FDRs of IBD patients (OR, 0.96; 95%CI, 0.91-1.02). The null association was consistent according to IBD subtype (Crohn's disease or ulcerative colitis), number of FDRs with IBD (1 or ≥2), age at first IBD diagnosis in FDRs (<18, 18-39, 40-59, or ≥60 years), maximum location/extent of IBD, or FDR relation (parent, sibling, or offspring). The null association remained for early-onset CRC (diagnosed at age <50 years). In conclusion, IBD history in FDRs was not associated with an increased risk of CRC. Our findings suggest that extra screening for CRC may not be needed in the offspring, siblings, or parents of IBD patients, and strengthen the theory that it is the actual inflammation or atypia of the colon in IBD patients that confers the increased CRC risk.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Cancer och onkologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Cancer and Oncology (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Gastroenterologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Gastroenterology and Hepatology (hsv//eng)

Nyckelord

Colorectal cancer

family history

first-degree relatives

inflammatory bowel disease

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)