Dietary consumption of meat has certain health benefits as it contains high biological-value proteins and important micronutrients. Yet, national health recommendations often advise people to limit intake of processed and red meat, which are linked to increased risks of death from heart disease, diabetes, and other illnesses. A meta-analysis of colorectal cancer in 10 cohort studies reported a 17% increased risk (95% CI 1.05-1.31) per 100g/day of red meat and an 18% increase (95% CI 1·10-1·28) per 50g/day of processed meat. Recently the International Agency for Research on Cancer (IARC) defined processed meat as carcinogenic to humans (group 1) and red meat, as probably carcinogenic to humans (Group 2a). However, the currently available data do not permit a conclusion about whether a safe consumption level exists. The Israeli diet is fundamentally different from the typical Western diet due to avoidance of pork meat as part of religious observance. No data are available on the level of risk of GI cancer associated with dietary meat and processed meat consumption in Israel.
Working Hypotheses and Aims:
We hypothesize that (1) the level of association found between meat consumption and GI cancer in the Israeli population is lower than previously reported; (2) Alcohol consumption and cigarette smoking will modify this association. The Aims of our study are: 1) Explore the level of association between meat consumption (red and processed) and gastrointestinal cancer risk in the Israeli adult population; 2) Explore the level of association between meat consumption (red and processed) and colorectal cancer risk in the Israeli adult population; 3) Characterize meat consumption habits in the Israeli population according to the main demographic subpopulations; 4) Explore possible modifying effects of other exposures (i.e. alcohol and cigarette smoking) on this association.
We propose a collaborative historical cohort study based on the individual participant data of 11 large nutritional studies conducted in Israel during the past 6 decades. The collaboration will include cohorts of the general Israeli healthy population and will identify which participants developed cancer and/or died from time of entry to the study until the end of 2015. A comprehensive study file, that will include all participating cohorts, will be established and harmonized for the various dietary assessment methods. For estimating usual intakes from 24-hr recall data methods developed at the NCI will be used. The identified study file will be linked to the Israeli Cancer Registry (INCR) and to the Central Population Registry for information on cancer incidence and vital status.
We anticipate observing approximately 1,200 gastrointestinal cancers and 700 colorectal cancers in this study. This will allow detection of a relative risk of 1.25 between those consuming processed meat (for example) one or more times per week compared to those who consume less, as statistically significant at the 5% level with a power of approximately 97% for gastrointestinal cancers and 84% for colorectal cancers.
Relevance of the application to food, nutrition & their effect on public health:
Following the recent IARC findings and WHO statement on red and processed meat consumption the Israel Ministry of Health was faced with the need to establish local recommendations. The present study will provide the scientific evidence necessary for these recommendations, thus having major public health implications.
Office of the Chief Scientist of the Ministry of Health
Starting date: March 2017