Poster Topical Area: Aging and Chronic Disease
Poster Board Number: 116
Objectives: To establish whether the incidence of colorectal cancer in Australia may have increased following the introduction of mandatory fortification of bread flour with folic acid in September 2009. It has previously been suggested that a small increase in colorectal cancer incidence in the USA and Canada in the late 1990ies, was the result of mandatory fortification of cereal grains with folic acid (1). However, others have suggested this was due to due to a screening effect (2).
Methods: We plotted age-standardised and age-specific incidence of colorectal cancer diagnosis (cases per 100,000), using data from the Australian Cancer Database, published by the Australian Institute of Health and Welfare. These data include all new cases of primary invasive colorectal cancers (ICD codes C18-C20) diagnosed in Australia between 1999-2014 (the most recent data available).
Results: Age-standardised colorectalcancer incidence was slightly higher in 2010 (62.6 per 100,000) compared to 2009 (61.6 cases per 100,000) (Figure 1). From 2011 to 2013, colorectal cancer incidence continued to decrease to 56.5 cases per 100,000 in 2013, with a small increase in 2014 (57.2 per 100,000). Age-specific data (Figure 2) indicates that the higher incidence in 2010 vs. 2009 was mainly due to the 55-59 yr (12% increase) and 65-69 yr (9% increase) age groups. These age-groups were affected by a suspension of the national bowel cancer screening program in May 2009, due to faulty Faecal Occult Blood Tests kits (3). The program was resumed in November 2009, and affected person were re-invited. Fluctuations in colorectal cancer incidence were also seen in earlier years, notably an apparent small increase in 2007, the year following introduction of the national bowel cancer screening program in 2006.
Conclusions: Causation cannot be assessed from these population-level data. However, the most likely explanations for the observed small fluctuations in colorectal cancer incidence are changes in bowel cancer screening participation, as well as normal random variation of colorectal cancer incidence in populations.
Jolieke van der Pols
Queensland University of Technology
Brisbane, Queensland, Australia