In a cohort of more than 487,000 adults in China, the consumption of tea on a daily basis was associated with reduced risk for ischemic heart disease, according to findings published in Heart.
“Intriguingly, daily tea consumers were at a lower risk [for ischemic heart disease] incidence than those who drank less than daily, but the increasing amount of tea did not further reduce the risk,” Liming Li, MD, MPH, from the department of epidemiology and biostatistics, School of Public Health, Peking University Health Science Center, Beijing, and colleagues wrote.
In a prospective study examining data from the China Kadoorie Biobank, researchers included 199,293 men and 288,082 women aged 30 to 79 years at baseline from 10 areas in China. All participants were enrolled from 2004 to 2008 and were followed until 2013. Participants with cancer, heart disease and stroke at baseline were excluded from the study.
“To our knowledge, this is by far the largest prospective study assessing the association between tea consumption and incident [ischemic heart disease]. We have carefully controlled for established and potential risk factors for [ischemic heart disease]. We measured tea consumption in gram of tea leaves added, which may be a better measure of tea consumption and at least partly reflect the intake amount of active ingredient,” the researchers wrote.
Polyphenols, particularly flavonoids, were considered the active ingredient in the tea consumed.
A total of 24,665 cases of incident ischemic heart disease (7.19 cases per 1,000 person-years) and 3,959 cases of major coronary events (1.13 cases per 1,000 person-years) were documented during the follow-up period (median, 7.2 years).
A reduced risk for ischemic heart disease and major coronary events was found to be associated with drinking tea. For all participants, the multivariable-adjusted HR for ischemic heart disease was 0.97 (95% CI, 0.94-1) for those who drank tea less than daily and 0.92 (95% CI, 0.88-0.95) for daily consumption vs. adults who did not drink tea at all during the past year. The multivariable-adjusted HR for major coronary events was 0.92 (95% CI, 0.85-1) for those who drank tea less than daily and 0.9 (95% CI, 0.82-0.99) for daily consumption vs. those who did not drink tea at all during the past year, according to the data.
Different amounts of tea used by participants who were daily consumers did not produce any linear trends in HRs for ischemic heart disease and major coronary events.
The researchers noted that a causal relationship was not established. “Given the observational nature, this study alone could not establish a causal relationship. Further randomized studies may be needed to confirm the protective effect of tea consumption on [ischemic heart disease].
“The present study yields compelling evidence on understanding the role of tea in [CV] health and referring tea as a healthy beverage,” they wrote. – by Suzanne Reist
The researchers report no relevant financial disclosures.