Physicians' Academy for Cardiovascular Education

Regular tea consumption associated with decreased incidence of CV events

Miller PE, et al, Am J Med, 2016

Associations between coffee, tea, and caffeine intake with coronary artery calcification and cardiovascular events


Miller PE, Zhao D, Frazier-Wood AC, et al.
Am J Med 2016; published online ahead of print
 

Background

Caffeine, the most studied active compound in tea and coffee, has short-term CV effects, including increased plasma renin levels, peripheral vasoconstriction, increased blood pressure, and cardiac arrhythmias. Nevertheless, it is associated with a lower incidence of diabetes and positive effects on endothelial function [1,2].
 
There are conflicting data regarding the association of coffee and tea intake with CV outcomes, probably due to potential confounding factors between coffee and tea consumption with demographic and other nutritional factors [3,4]. Yet, it is critical to study a diverse population withmsociodemographic and clinical characteristics.
 
In this analysis, the association between coffee and tea intake with coronary artery calcium (CAC) prevalence, progression, and CV events was evaluated in 6,508 participants of the Multi-Ethnic Study of Atherosclerosis (MESA). Individuals with a CV disease history were excluded and mean follow-up was 11.1 years.
 

Main results

  • The percentage of participants drinking 0, <1, and ≥1 cup/day of coffee were 25.0%, 24.0%, and 50.9%, respectively. For tea, this was 57.6%, 29.5% and 12.9% respectively.
  • The prevalence of CAC score 0, 1-99, and ≥100 was 49.9%, 26.5%, and 23.6%, respectively.
  • The incidence of all CV events and hard CV events was 10.8 and 7.5 per 1000 person-years, respectively.
  • ≥1 cup/day of coffee had a higher prevalence of CAC scores ≥100 compared to no coffee: RR for CAC score ≥100: 1.10 (95% CI: 0.89-1.35) with multivariable adjustment. It was not associated with CAC progression.
  • ≥1 cup/day of tea had a lower prevalence of CAC scores ≥100 compared to no tea: RR: 0.64 (95% CI: 0.49-0.84) with multivariable adjustment. Higher intake was also associated with reduced progression of CAC: progression ratio 0.73 (95% CI: 0.61-0.87).
  • Higher caffeine consumption (2nd vs 1st tertile) was less often associated with CAC scores ≥100: RR: 0.81 (95% CI: 0.66-1.00). Higher intake was also associated with less CAC progression (progression ratio: 0.87; 95% CI: 0.76-1.00; comparing 3rd vs 1st tertile).
  • Statistically significant interactions for CAC progression were caffeine and smoking (P=0.008) and caffeine and gender (P=0.02). These association were stronger in non-smokers and former smokers compared to current smokers and in men compared to women.
  • <1 cup/day of coffee was associated with an increased incidence of CV events compared to no coffee (HR: 1.28; 95% CI: 1.02-1.61). This was not observed for ≥1 cup of coffee per day.
  • ≥1 cup/day of tea was associated with a lower incidence of CV events compared to no tea (HR: 0.71; 95% CI: 0.53-0.95).
  • Caffeine intake was not associated with CV events.
 

Conclusion

Regular tea consumption was associated with a decreased prevalence and progression of coronary artery calcium, and with a decreased incidence of CV events. These data support regular tea consumption as part of a heart healthy diet as recommended by the American Heart Association.
 
Although occasional coffee intake was associated with increased CV incidence, a neutral association between regular coffee and caffeine intake with incident CV outcomes and coronary artery calcium was observed. This suggests regular intake is safe.
 
Find this article online at Am J med
 

References

1. Robertson D, Frolich JC, Carr RK, et al. Effects of caffeine on plasma renin activity, catecholamines and blood pressure. N Engl J Med 1978;298:181-186.
2. Huxley R, Lee CM, Barzi F, et al. Coffee, decaffeinated coffee, and tea consumption in relation to incident type 2 diabetes mellitus: a systematic review with meta-analysis. Arch Intern Med 2009;169:2053-2063
3. Ding M, Bhupathiraju SN, Satija A, et al. Long-term coffee consumption and risk of cardiovascular disease: a systemic review and a dose-response meta-analysis of prospective cohort studies. Circulation 2014;129:643-659
4. Sofi F, Conti AA, Gori AM, et al. Coffee consumption and risk of coronary heart disease: a meta-analysis. Nutr Metab Cardiovasc Dis 2007;17:209–223