Research Article Is Month of Birth a Risk Factor for Colorectal Cancer? N. K. Francis, 1,2 N. J. Curtis, 1,3 E. Noble, 1 M. Cortina-Borja, 4 and E. Salib 5 1 Department of General Surgery, Yeovil District Hospital NHS Foundation Trust, Higher Kingston, Yeovil BA21 4AT, UK 2 Faculty of Science, University of Bath, Wessex House 3.22, Bath BA2 7AY, UK 3 Department of Surgery and Cancer, Imperial College London, Floor 10, QEQM Building, St. Mary’s Hospital, Praed Street, London W2 1NY, UK 4 Centre for Paediatric Epidemiology and Biostatistics, Institute of Child Health, University College London, 30 Guilford St, London WC1N 1EH, UK 5 Faculty of Health and Life Sciences, University of Liverpool, Brownlow Hill, Liverpool L69 3BX, UK Correspondence should be addressed to N. K. Francis; nader.francis@ydh.nhs.uk Received 8 September 2016; Revised 9 November 2016; Accepted 22 November 2016; Published 4 January 2017 Academic Editor: Paolo Gionchetti Copyright © 2017 N. K. Francis et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Introduction. Te developmental origins of health and disease hypothesis and season of birth have been linked to a wide variety of later life conditions including cancer. Whether any relationship between month and season of birth and colorectal cancer exists is unknown. Methods. A case-control study was performed with month of birth extracted from a dedicated colorectal cancer database. Age and gender matched patients were used as a control group. Generalised linear models were ftted with Poisson and negative binomial responses and logarithmic links. A forward stepwise approach was followed adding seasonal components with 6- and 12- month periods. Results. 1019 colorectal cancer patients and 1277 randomly selected age and gender matched controls were included. For both men and women there is an excess of colorectal cancer in those born in autumn and a corresponding reduction of risk among those born in spring (p = 0.026). For the identifed September peak, the excess risk for colorectal cancer was 14.8% (95% CI 5.6–32.3%) larger than the spring trough. Conclusion. Tere is a seasonal efect in the monthly birth rates of people who are operated for colorectal cancer with a disproportionate excess of cancer in those born in September. Further large studies are required to validate these fndings. 1. Introduction Te developmental origins of health and disease hypothesis states that intrauterine and early life environmental condi- tions have a signifcant impact upon health and development that persists through into adult life [1]. Tis concept was developed from the Barker hypothesis following the epidemi- ological identifcation of poor foetal and early life nutrition to an increased risk of coronary heart disease [2]. Tis paradigm shif altered our understanding to seeing later life risk as representing a combination of genetic predisposition, lifestyle factors, and early life events during the plastic phase of development. Season or month of birth can result in difering early environmental exposure to a variety of stimuli such as sunlight, temperature, and infectious pathogens which could infuence physiological and immunological development. Epidemiological studies have linked season of birth with a wide variety of conditions including lifespan and mortality risk [3–5], cardiovascular events [2, 6], type II diabetes [7], hypertension [8], mental health conditions [9], and suicide risk [10]. An association with season of birth has also been identifed in malignant conditions such as childhood and adolescent haematological [11–13] and central nervous system cancers [14]. Proof of principle that season of birth can infuence malignancy risk through long latency periods to adult onset cancer is suggested by available reports on skin [15, 16], breast [17], ovarian [18], and brain tumours [19]. Tere is a paucity of studies investigating gastrointestinal conditions [20, 21], particularly malignancies that typically present in later life. Hindawi Gastroenterology Research and Practice Volume 2017, Article ID 5423765, 5 pages https://doi.org/10.1155/2017/5423765