RESEARCH ARTICLE The impact of supplemen

rt1 Background colonoscopy investigation for abnormal results. Trials of McGregor et al. BMC Cancer (2015) 15:162 DOI 10.1186/s12885-015-1167-3prived areas in England [11]. Therefore, further strategiesEpidemiology and Public Health, University College London, London, UK Full list of author information is available at the end of the articleColorectal cancer (CRC) is the second most common cause of cancer death in the US and Europe [1,2]. Early detection through population-based screening is consid-ered key to reducing CRC mortality rates [3,4]. In England, a national CRC screening programme was introduced in 2006 and is offered biennially to all men and women between 60 and 74. It is based on the home-based guaiac faecal occult blood test (FOB test) with follow-up this screening approach in the UK have shown a 10-13% reduction in CRC mortality in intention-to-treat analyses, rising to 27 % among those who returned the FOB test kits [5,6]. Delivery of the CRC screening programme uses strat-egies known to maximise screening participation such as automated mailing of the FOB test to homes [7], pre-notification [8], and reminders (e.g. [9,10]). However, CRC screening uptake remains around 54%. There is also a strong socioeconomic gradient, with uptake ranging from 35 % in the most deprived areas to 61 % in the least de