A Prospective Population-based Cohort Study On The Association Between Tea Drinking And Dairy Product Intake And Ischemic Heart Disease

Objective:Ischemic heart disease is a kind of cardiovascular disease,which brings a heavy burden to our country.China is a big consumer of tea.Catechins,one of the active ingredients in tea,can inhibit Ca²⁺overload and protect myocardium.The risk of IHD in low BMD population is higher,while caffeine in tea can promote calcium loss.There have been a number of related studies on the association between tea drinking and calcium and IHD,but the conclusions are inconsistent.The purpose of this study was to investigate the situation of tea drinking behavior,dairy products,and IHD among residents in Qingdao,and analyzed the association between the tea-drinking behavior and the calcium level in the body and IHD,thus providing an important basis for the prevention and treatment of IHD in China.Methods:This study was a prospective cohort design.A follow-up cohort of 33,681 people aged 30-76 years was established from 2004 to 2008 based on baseline information of35,509 residents from 12 sub-district offices in Licang District,Qingdao..The morbidity and medical treatment information of the study subjects were obtained mainly through the disease surveillance system and the medical insurance system in China.The death information of the subjects was obtained through the public security system,medical insurance records,and household investigation.Cox regression model was used to analyze the association between tea and dairy intake and the risk of IHD.The effects of tea drinking,calcium intake,and the combination of tea consumption and dairy intake on IHD were further explored by stratified analysis by gender and self-reported amenorrhea.Sensitivity analysis was performed.Results:（1）The incidence of IHD was 8.23%,of which 8.95%was female,significantly higher than male（7.34%）X²=24.43,P<0.01.The subjects’educational level,household income,smoking,drinking alcohol and physical activity were all associated with the incidence of IHD.（2）The"weekly tea drinking"was the most prevalent among residents,accounting for 62.5%,and the proportion of male tea drinking was higher than that of female tea drinking（P<0.001）.Among the tea drinkers,99.5%drank green tea,and male tea consumption was higher than female tea consumption（P<0.01）.Educational level,annual household income,smoking,drinking and physical activity were all associated with tea-drinking behavior.The intake of dairy products was mainly"daily intake",accounting for 38.0%,and the amount of dairy consumption in females was higher than that in males（P<0.001）."Daily consumption"levels of education and annual household income were also associated with dairy consumption..（3）After adjusted for gender,age,education,annual family income,physical activity,marital status,smoking,family history of diabetes,family history of stroke,and other risk factors,Cox regression analysis showed that“daily tea consumption”decreased the risk of IHD in the total population compared with non-tea consumption group（HR=0.91,95%CI:0.84-0.99）.Further gender analysis shows that,in men,drinking tea is the same as the total population.However,in the female population,there was no statistical difference between tea drinking behavior and the incidence of IHD,and the protective effect of tea drinking on IHD disappeared.Among postmenopausal women,the risk of IHD was increased in those who drank"tea>6g daily"compared with those who did not drink tea（HR=3.11,95%CI:1.23-7.87）.（4）The risk of IHD was lower in the"daily dairy products"group than in the"<once/month"group（HR=0.42,95%CI:0.21-0.84）;The"daily tea and dairy consumption"group had a lower risk of IHD than the"no tea and dairy consumption"group（HR=0.69,95%CI:0.6-0.8）.The results of sensitivity analysis were consistent with the results of overall population analysis.Conclusion:Tea drinking behavior and dairy intake of residents are related to the risk of IHD.Increased tea intake can reduce the risk of IHD.There are differences between different genders in tea drinking and IHD risk.Dairy intake was not found to reduce the risk of IHD in the general population,but daily consumption of dairy products was associated with a reduced risk of IHD in postmenopausal women.The daily intake of>6g was associated with an increased risk of IHD in postmenopausal women with low calcium levels,and it is recommended to reduce tea consumption in those with calcium deficiency or postmenopausal women.