title: Habitual coffee consumption and risk of type 2 diabetes, ischemic heart disease, depression and Alzheimer's disease: a Mendelian randomization study.
abstract: Observationally, coffee is inversely associated with type 2 diabetes mellitus (T2DM), depression and Alzheimer's disease, but not ischemic heart disease (IHD). Coffee features as possibly protective in the 2015 Dietary Guidelines for Americans. Short-term trials suggest coffee has neutral effect on most glycemic traits, but raises lipids and adiponectin. To clarify we compared T2DM, depression, Alzheimer's disease, and IHD and its risk factors by genetically predicted coffee consumption using two-sample Mendelian randomization applied to large extensively genotyped case-control and cross-sectional studies. Childhood cognition was used as a negative control outcome. Genetically predicted coffee consumption was not associated with T2DM (odds ratio (OR) 1.02, 95% confidence interval (CI) 0.76 to 1.36), depression (0.89, 95% CI 0.66 to 1.21), Alzheimer's disease (1.17, 95% CI 0.96 to 1.43), IHD (0.96, 95% CI 0.80 to 1.14), lipids, glycemic traits, adiposity or adiponectin. Coffee was unrelated to childhood cognition. Consistent with observational studies, coffee was unrelated to IHD, and, as expected, childhood cognition. However, contrary to observational findings, coffee may not have beneficial effects on T2DM, depression or Alzheimer's disease. These findings clarify the role of coffee with relevance to dietary guidelines and suggest interventions to prevent these complex chronic diseases should be sought elsewhere.
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China.
authors.forename: Man Ki
authors.initials: MK
authors.lastname: Kwok
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China.
authors.forename: Gabriel M
authors.initials: GM
authors.lastname: Leung
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China.|City University of New York Graduate School of Public Health and Health Policy, New York, United States.
authors.forename: C Mary
authors.initials: CM
authors.lastname: Schooling
mesh_terms: D000328:Adult; D000544:Alzheimer Disease / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D003069:Coffee; D003863:Depression / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D057182:Mendelian Randomization Analysis; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D012307:Risk Factors
chemical_list: D003069:Coffee