Tea consumption and risk of ischaemic heart disease

Abstract

Objective: To prospectively examine the association between tea consumption and the risk of ischaemic heart disease (IHD).

Methods: Prospective study using the China Kadoorie Biobank; participants from 10 areas across China were enrolled during 2004-2008 and followed up until 31 December 2013. After excluding participants with cancer, heart disease and stroke at baseline, the present study included 199 293 men and 288 082 women aged 30-79 years at baseline. Information on IHD incidence was collected through disease registries and the new national health insurance databases.

Results: During a median follow-up of 7.2 years, we documented 24 665 (7.19 cases/1000 person-years) incident IHD cases and 3959 (1.13 cases/1000 person-years) major coronary events (MCEs). Tea consumption was associated with reduced risk of IHD and MCE. In the whole cohort, compared with participants who never consumed tea during the past 12 months, the multivariable-adjusted HRs and 95% CIs for less than daily and daily tea consumers were 0.97 (0.94 to 1.00) and 0.92 (0.88 to 0.95) for IHD, 0.92 (0.85 to 1.00) and 0.90 (0.82 to 0.99) for MCE. No linear trends in the HRs across the amount of tea were observed in daily consumers for IHD and MCE (P_Linear >0.05). The inverse association between tea consumption and IHD was stronger in rural (P_Interaction 0.006 for IHD, <0.001 for MCE), non-obese (P_Interaction 0.012 for MCE) and non-diabetes participants (P_Interaction 0.004 for IHD).

Conclusions: In this large prospective study, daily tea consumption was associated with a reduced risk of IHD.

Figure 1

Subgroup analysis of associations between daily tea consumption and risk of ischaemic heart disease (IHD) according to potential baseline risk factors. HRs for IHD or major coronary events (MCEs) are for comparison of daily tea consumer with participants who never consumed tea during the past 12 months. Risk estimates for other categories of tea consumption are shown in online supplementary table S3. Solid dots represent point estimates, and horizontal lines represent 95% CIs. An HR of <1 means daily tea consumption was associated with a reduction in the risk of the outcome of interest. The tests for interaction were performed using likelihood ratio tests, which involved comparing models with and without cross-product terms between the baseline stratifying variable and tea consumption as an ordinal variable. BMI, body mass index; MET, metabolic equivalent task.