BackgroundIncidences of colorectal cancer (CRC) and inflammatory bowel disease (IBD) are increasing in those aged AimTo identify and quantify clinical features in primary care of CRC/IBD in those aged Design and settingMatched case-control study using primary care records from the Clinical Practice Research Datalink, UK.MethodIncident cases (aged n = 1661) and IBD (n = 9578) diagnosed between 2000 and 2013 were each matched with up to three controls (n = 3979 CRC; n = 22 947 IBD). Odds ratios (OR) and positive predictive values (PPV) were estimated for features of CRC/IBD in the year before diagnosis.ResultsTen features were independently associated with CRC/IBD (all P3% for rectal bleeding with diarrhoea, thrombocytosis, low MCV, low haemoglobin or raised inflammatory markers; for change in bowel habit with low MCV, thrombocytosis or low haemoglobin; and for diarrhoea with thrombocytosis.ConclusionThis study quantified the risk of serious bowel disease in symptomatic patients aged