Meat consumption and risk of 25 common conditions: outcome-wide analyses in 475,000 men and women in the UK Biobank study
Authors: Paul N Appleby
Georgina K Fensom
Ruth C Travis
Aurora Perez-Cornago
Tammy Y N Tong
Keren Papier
Anika Knuppel
Julie A Schmidt
Timothy J Key
Journal: BMC Medicine (2021)
Discipline: CLINICAL MEDICINE
Keywords: Outcome-wide; Poultry; Processed meat; Prospective cohort study; Red meat
Affiliations: Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Richard Doll Building, Old Road Campus, Oxford, OX3 7LF, UK. ., Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Richard Doll Building, Old Road Campus, Oxford, OX3 7LF, UK., Department of International Development, University of Oxford, 3 Mansfield Rd, Oxford, OX1 3TB, UK.

Abstract:  Background: There is limited prospective evidence on the association between meat consumption and many common, non-cancerous health outcomes. We examined associations of meat intake with risk of 25 common conditions (other than cancer). Methods: We used data from 474,985 middle-aged adults recruited into the UK Biobank study between 2006 and 2010 and followed up until 2017 (mean follow-up 8.0 years) with available information on meat intake at baseline (collected via touchscreen questionnaire), and linked hospital admissions and mortality data. For a large sub-sample (~ 69,000), dietary intakes were re-measured three or more times using an online, 24-h recall questionnaire. Results: On average, participants who reported consuming meat regularly (three or more times per week) had more adverse health behaviours and characteristics than participants who consumed meat less regularly, and most of the positive associations observed for meat consumption and health risks were substantially attenuated after adjustment for body mass index (BMI). In multi-variable adjusted (including BMI) Cox regression models corrected for multiple testing, higher consumption of unprocessed red and processed meat combined was associated with higher risks of ischaemic heart disease (hazard ratio (HRs) per 70 g/day higher intake 1.15, 95% confidence intervals (CIs) 1.07-1.23), pneumonia (1.31, 1.18-1.44), diverticular disease (1.19, 1.11-1.28), colon polyps (1.10, 1.06-1.15), and diabetes (1.30, 1.20-1.42); results were similar for unprocessed red meat and processed meat intakes separately. Higher consumption of unprocessed red meat alone was associated with a lower risk of iron deficiency anaemia (IDA: HR per 50 g/day higher intake 0.80, 95% CIs 0.72-0.90). Higher poultry meat intake was associated with higher risks of gastro-oesophageal reflux disease (HR per 30 g/day higher intake 1.17, 95% CIs 1.09-1.26), gastritis and duodenitis (1.12, 1.05-1.18), diverticular disease (1.10, 1.04-1.17), gallbladder disease (1.11, 1.04-1.19), and diabetes (1.14, 1.07-1.21), and a lower IDA risk (0.83, 0.76-0.90). Conclusions: Higher unprocessed red meat, processed meat, and poultry meat consumption was associated with higher risks of several common conditions; higher BMI accounted for a substantial proportion of these increased risks suggesting that residual confounding or mediation by adiposity might account for some of these remaining associations. Higher unprocessed red meat and poultry meat consumption was associated with lower IDA risk. 

Retracted: No

PubPeer comments:
 When Ho et al examined the associations between macronutrients and CVD and mortality outcomes in the same UK BioBank cohort in March 2020, they found strong associations with mortality for higher intakes of sugar, total carbohydrate, polyunsaturated fat, and saturated fat. [1] All but saturated fat were also associated with CVD mortality. Interestingly, there was a null association between saturated fat and mortality in the half of the UK biobank cohort consuming below the median intake of energy from carbohydrate, 49.76% (fig S10). In substitution analysis,  When energy intake remained constant, replacing sugar with starch, MUFA, and protein (fig 3) was associated with lower risk of all cause mortality and incident CVD when replacement was up to 30% of energy from starch, 25% from MUFA, and 20% from protein. The animal foods analyzed by Papier et al. are major sources of MUFA and protein in UK BioBank. It seems striking that these macronutrient intakes, with strong associations for all-cause and CVD mortality already published, were not adjusted for and that sugar and carbohydrate were not mentioned by Papier et al. The finding of Ho et al. that a harmful association for SFA only existed within high-carbohydrate diets has strong mechanistic support.[2] A similar mechanism may apply to associations for dietary cholesterol, and it would be valuable to test the interaction between carbohydrate and meat. A further point is the non-specificity of outcomes, failing a Bradford Hill test. Meat is associated with COPD; however the Nurses Health Study found that disinfectant exposure was a strong risk factor for COPD.[3] Exposures to chemicals are not listed in Papier et al, yet it is reasonable to think that overall higher meat eaters are more likely to be exposed to workplace and environmental chemical exposures (including also carcinogens). To quote Hermann Melville, u201cOf all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well- warmed, and well-fed.u201d Here, the assumption is that the diseases of the poor are caused by their having access to nutritious foods, while some other very relevant factors - less nutritious foods, workplace and environmental chemical exposures - are not being considered. [1] Ho F K, Gray S R, Welsh P, Petermann-Rocha F, Foster H, Waddell H et al. Associations of fat and carbohydrate intake with cardiovascular disease and mortality: prospective cohort study of UK Biobank participants BMJ 2020; 368 :m688 doi:10.1136 bmj.m688 [2] Kuipers RS, de Graaf DJ, Luxwolda MF, Muskiet MH, Dijck-Brouwer DA, Muskiet FA. Saturated fat, carbohydrates and cardiovascular disease. Neth J Med. 2011 Sep;69(9):372-8. PMID: 21978979. [3] Dumas O, Varraso R, Boggs KM, et al. Association of Occupational Exposure to Disinfectants With Incidence of Chronic Obstructive Pulmonary Disease Among US Female Nurses. JAMA Netw Open. 2019;2(10):e1913563. doi:10.1001 jamanetworkopen.2019.13563 ,