Estimated effects of reductions in processed meat consumption and unprocessed red meat consumption on occurrences of type 2 diabetes, cardiovascular disease, colorectal cancer, and mortality in the USA: a microsimulation study
Authors: Joe Kennedy, Peter Alexander, Lindsey Smith Taillie, Lindsay M Jaacks
Journal: The Lancet Planetary Health (2024)

BackgroundHigh consumption of processed meat and unprocessed red meat is associated with increased risk of multiple chronic diseases, although there is substantial uncertainty regarding the relationship for unprocessed red meat. We developed a microsimulation model to estimate how reductions in processed meat and unprocessed red meat consumption could affect rates of type 2 diabetes, cardiovascular disease, colorectal cancer, and mortality in the US adult population.MethodsWe used data from two versions of the US National Health and Nutrition Examination Survey, one conducted during 2015–16 and one conducted during 2017–18, to create a simulated US population. The starting cohort was restricted to respondents aged 18 years or older who were not pregnant and had 2 days of dietary-recall data. First, we used previously developed risk models to estimate the baseline disease risk of an individual. For type 2 diabetes we used a logistic-regression model and for cardiovascular disease and colorectal cancer we used Cox proportional-hazard models. We then multiplied baseline risk by relative risk associated with individual processed meat and unprocessed red meat consumption. Prevented occurrences of type 2 diabetes, cardiovascular disease, colorectal cancer, and mortality were computed by taking the difference between the incidence in the baseline and intervention scenarios. All stages were repeated for ten iterations to correspond to a 10-year time span. Scenarios were reductions of 5%, 10%, 30%, 50%, 75%, and 100% in grams consumed of processed meat, unprocessed red meat, or both. Each scenario was repeated 50 times for uncertainty analysis.FindingsThe total number of individual respondents included in the simulated population was 8665, representing 242 021 876 US adults. 4493 (51·9%) of 8665 individuals were female and 4172 (48·1%) were male; mean age was 49·54 years (SD 18·38). At baseline, weighted mean daily consumption of processed meat was 29·1 g, with a 30% reduction being 8·7 g per day, and of unprocessed red meat was 46·7 g, with a 30% reduction being 14·0 g per day. We estimated that a 30% reduction in processed meat intake alone could lead to 352 900 (95% uncertainty interval 345 500–359 900) fewer occurrences of type 2 diabetes, 92 500 (85 600–99 900) fewer occurrences of cardiovascular disease, 53 300 (51 400–55 000) fewer occurrences of colorectal cancer, and 16 700 (15 300–17 700) fewer all-cause deaths during the 10-year period. A 30% reduction in unprocessed red meat intake alone could lead to 732 600 (725 700–740 400) fewer occurrences of type 2 diabetes, 291 500 (283 900–298 800) fewer occurrences of cardiovascular disease, 32 200 (31 500–32 700) fewer occurrences of colorectal cancer, and 46 100 (45 300–47 200) fewer all-cause deaths during the 10-year period. A 30% reduction in both processed meat and unprocessed red meat intake could lead to 1 073 400 (1 060 100–1 084 700) fewer occurrences of type 2 diabetes, 382 400 (372 100–391 000) fewer occurrences of cardiovascular disease, 84 400 (82 100–86 200) fewer occurrences of colorectal cancer, and 62 200 (60 600–64 400) fewer all-cause deaths during the 10-year period.InterpretationReductions in processed meat consumption could reduce the burden of some chronic diseases in the USA. However, more research is needed to increase certainty in the estimated effects of reducing unprocessed red meat consumption.FundingThe Wellcome Trust.