BACKGROUND AND PURPOSE:

• Coffee consumption has been shown to reduce the risk of type 2 diabetes (T2D)
• Yang et al. (American Journal of Clinical Nutrition, 2022) assessed whether greater habitual coffee consumption was associated with a lower risk of T2D among high-risk women with a history of gestational diabetes (GDM)

METHODS:

• Prospective cohort study
  • NHS II (see ‘Learn More – Primary Sources’, below)
  • Between 1991 and 2017
• Participants
  • Individuals with a history of GDM
• Exposure
  • Self-reported consumption of caffeinated and decaffeinated coffee
• Study design
  • Demographic, lifestyle factors including diet, and disease outcomes were collected every 2 to 4 years
  • Fasting blood samples were collected from 2012 to 2014 from a subset of participants free of diabetes to measure glucose metabolism biomarkers (HbA1c, insulin, C-peptide)
  • Multivariable Cox regression models were used to calculate adjusted hazard ratio (HR) and 95% CIs for the risk of T2D
  • The least squares mean of glucose metabolic biomarkers were calculated according to coffee consumption
• Primary outcome
  • Type 2 diabetes

RESULTS:

• 4522 participants
  • Developed T2D: 979 participants
• Compared to consuming zero cups per day, caffeinated coffee consumption was inversely associated with the risk of T2D
  • ≤1 (nonzero) cups per day: aHR 0.91 (95% CI, 0.78 to 1.06)
  • 2 to 3 cups per day: aHR 0.83 (95% CI, 0.69 to 1.01)
  • ≥4 cups per day: aHR 0.46 (95% CI, 0.28 to 0.76)
  • P_trend=0.004
• Replacing 1 serving per day of sugar-sweetened beverage or artificially sweetened beverage with one cup of caffeinated coffee lowered the risk of T2D
  • Replacing sugar-sweetened beverage: Risk ratio (RR) 0.83 (95% CI, 0.75 to 0.93)
  • Replacing artificially sweetened beverage: RR 0.91 (95% CI, 0.84 to 0.99)
• Greater caffeinated coffee consumption was associated with lower
  • Fasting insulin
  • C-peptide concentrations (P_trend<0.05)
• Decaffeinated coffee intake was not significantly related to T2D but was inversely associated with C-peptide concentrations (P_trend=0.003)

CONCLUSION:

• Women with a history of GDM who drank caffeinated coffee on a regular basis had a lowered risk of T2D and a more favorable metabolic profile

Learn More – Primary Sources:

Habitual coffee consumption and subsequent risk of type 2 diabetes in individuals with a history of gestational diabetes – a prospective study

Nurses’ Health Study (NHS I) and Nurses’ Health Study II (NHS II)

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