Coffee intake, plasma caffeine levels, and diabetic microvascular complications: A Mendelian randomization study

Area of Science:

• Genetics and Epidemiology
• Metabolic Disorders
• Nutritional Science

Background:

• Diabetic microvascular complications are a major health concern.
• The role of lifestyle factors like coffee consumption in these complications requires clarification.
• Causality assessment is needed to understand the relationship between coffee intake and diabetic complications.

Purpose of the Study:

• To investigate the causal relationship between coffee intake, plasma caffeine levels, and diabetic microvascular complications.
• To assess the impact of genetically predicted coffee consumption on diabetic retinopathy, nephropathy, and neuropathy.
• To explore the protective potential of coffee and caffeine in diabetes management.

Main Methods:

• Mendelian randomization (MR) analysis was employed using data from FinnGen.
• Genome-wide association study meta-analyses identified single nucleotide polymorphisms for coffee intake and plasma caffeine.
• Univariable and multivariable MR analyses were conducted, with adjustments for smoking in the latter.

Main Results:

• Genetically predicted higher coffee intake showed a slight increase in risk for diabetic retinopathy and nephropathy in univariable MR.
• Multivariable MR revealed a significant protective effect of coffee intake on diabetic retinopathy and a suggestive protective effect on nephropathy.
• Higher plasma caffeine levels also demonstrated a suggestively protective association with these diabetic microvascular complications.

Conclusions:

• Genetically predicted higher coffee intake and plasma caffeine levels appear protective against diabetic retinopathy and nephropathy.
• These findings suggest a potential role for coffee consumption in mitigating diabetic microvascular complications.
• Further research is recommended to confirm these results and explore their clinical implications for diabetes care.