An Israeli Collaborative Study on Meat Consumption and Gastrointestinal Cancer: Pooled Analysis of Individualized Nutritional Data - methodological Challenges and Preliminary Results

סיון בן אברהם ^1,4 Angela Chetrit ^1,4 Arnona Ziv ³ Laurence S. Freedman ² Nirit Agai ¹ Ofra Kalter Leibovici ^1,5 Kathleen Abu-Saad ¹ Danit R. Shahar ⁶ Uri Goldbourt ⁵ Lital Keinan-Boker ⁷ Gad Rennert ^8,9,10 Siegal Sadetzki ^5,11 Rachel Dankner ^1,5
¹Unit for Cardiovascular Epidemiology, The Gertner Institute for Epidemiology and Health Policy Research, Israel
²The Biostatistics and Biomathematics Unit, The Gertner Institute for Epidemiology and Health Policy Research, Israel
³The Information & Computerization Unit, The Gertner Institute for Epidemiology and Health Policy Research, Israel
⁴Cancer and Radiation Epidemiology Unit, The Gertner Institute for Epidemiology and Health Policy Research, Israel
⁵Department of Epidemiology and Preventive Medicine, School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Israel
⁶Department of Public Health, The S. Daniel Abraham International Center for Health and Nutrition, Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel
⁷Israel Center for Disease Control, Ministry of Health, Israel
⁸Department of Community Medicine and Epidemiology, Lady Davis Carmel Medical Center, Israel
⁹Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Israel
¹⁰National Cancer Control Center, Clalit Health Services, Israel
¹¹Public Health Service, Ministry of Health, Israel

Background: In 2015 the International Agency for Research on Cancer (IARC) defined processed meat as carcinogenic (Group-1) and red meat as probably carcinogenic (Group-2a). The Israeli diet is fundamentally different from the typical Western diet due to avoidance of pork meat and consumption of salty kosher meat.

Aims: We aim to characterize meat consumption habits in the Israeli population according to main demographic subpopulations; to explore the level of association between meat consumption (red and processed) and gastrointestinal cancer risk; and to explore possible modifying effects of other exposures.

Methods: This is a collaborative historical cohort study based on the individual participant data of 7 large cohort studies (N=29,560), conducted in Israel between 1963 and 2005. Participants who developed cancer and/or died during follow-up (by 31/12/2015) were identified by linkage to the Israeli Cancer Registry (INCR) and to the Central Population Registry. Nutritional intake was collected using food frequency questionnaires (FFQ) or 24-hour recall questionnaires (24-HRQ).

Results: Age range of participants at baseline was 16-90 and 11% were Israeli Arabs. A total of 1,380 were diagnosed with any type of digestive tract cancer, of them 958 with colorectal cancer. In a preliminary analysis of 12,722 participants (using FFQ`s), mean red and processed meat intake (including poultry) were 31-39 gr/day and 41-46 gr/day, respectively. Mean ultra-processed meat intake (sausages, hotdogs, pastrami etc.) was 6-12gr/day. Analysis of 24-HRQ (n=1,799) revealed that 73% and 85% did not consume any red meat and any processed meat, respectively.

Discussion: Using data from different cohort studies will increase population diversity and power to detect associations. Preparation of the database for this study posed several challenges including: harmonizing demographics, FFQ`s and nutritional databases and estimating habitual intake using 24-HRQ. Red and processed meat intakes are lower in our population than in studies from other countries.