Associations of Total Legume, Pulse, and Soy Consumption with Incident Type 2 Diabetes

Background: The consumption of legumes is promoted as part of a healthy diet in many countries but associations of total and types of legume consumption with type 2 diabetes (T2D) are not well established. Analyses across diverse populations are lacking despite the availability of unpublished legume consumption data in prospective cohort studies. Objective: To examine the prospective associations of total and types of legume intake with the risk of incident T2D. Methods: Meta-analyses of associations between total legume, pulse, and soy consumption and T2D were conducted using a federated approach without physical data-pooling. Prospective cohorts were included if legume exposure and T2D outcome data were available and the cohort investigators agreed to participate. We estimated incidence rate ratios (IRRs) and CIs of associations using individual participant data including ≤42,473 incident cases among 807,785 adults without diabetes in 27 cohorts across the Americas, Eastern Mediterranean, Europe, and Western Pacific. Random-effects meta-analysis was used to combine effect estimates and estimate heterogeneity. Results: Median total legume intake ranged from 0-140 g/d across cohorts. We observed a weak positive association between total legume consumption and T2D (IRR = 1.02, 95% CI: 1.01 to 1.04) per 20 g/d higher intake, with moderately high heterogeneity (I2 = 74%). Analysis by region showed no evidence of associations in the Americas, Eastern Mediterranean, and Western Pacific. The positive association in Europe (IRR = 1.05, 95% CI: 1.01 to 1.10, I2 = 82%) was mainly driven by studies from Germany, UK, and Sweden. No evidence of associations was observed for the consumption of pulses or soy. Conclusions: These findings suggest no evidence of an association of legume intakes with T2D in several world regions. The positive association observed in some European studies warrants further investigation relating to overall dietary contexts in which legumes are consumed, including accompanying foods which may be positively associated with T2D. Funding for the InterConnect project was provided by the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 602068. Additionally, investigators acknowledge funding from the following agencies: NJW, NGF, FI, and MP acknowledge funding from the Medical Research Council Epidemiology Unit (MC_UU_12015/1 and MC_UU_12015/5); NJW and NGF acknowledge support from National Institute of Health Research (NIHR) Biomedical Research Centre Cambridge: Nutrition, Diet, and Lifestyle Research Theme (IS-BRC-1215-20014). TB acknowledges funding from EUCAN-Connect under the European Union's Horizon 2020 research and innovation programme (grant agreement no. 824989). MBR and MAMG acknowledge funding from the Spanish Government Instituto de Salud Carlos III and the European Regional Development Fund (FEDER) (PI17/01795). JK acknowledges funding from the Korea Centers for Disease Control and Prevention, Ministry for Health and Welfare, Republic of Korea (4845-301 and 4851-302), and the Collaborative Genome Program for Fostering New Post-Genome Industry of the National Research Foundation (NRF) funded by the Ministry of Science and ICT (NRF-2017M3C9A6047623). RM acknowledges funding from the Tehran University of Medical Sciences (grant number: 81/15), Cancer Research UK (grant number: C20/A5860), the Intramural Research Program of the U.S. National Cancer Institute, NIH, and the International Agency for Research on Cancer. LB acknowledges that the Cohort of Swedish Men (COSM) and the Swedish Mammography Cohort (SMC) are part of the Swedish Infrastructure for Medical Population-Based Life-Course and Environmental Research (SIMPLER), which receives funding from the Swedish Research Council (2017-00644). BD is an investigator of the Brazilian National Health Technology Assessment Institute and SC received a fellowship from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), the Brazilian National Council for Scientific and Technological Development Fund (FEDER) (PI17/01795). The Zutphen Elderly Study was funded by The Netherlands Prevention Foundation, The Hague, The Netherlands and the National Institute of Aging, Bethesda, MD, USA. The funding sources did not participate in the design or conduct of the study; collection, management, analysis, or interpretation of the data; or preparation, review, or approval of the manuscript.