Subgroup analyses of associations between tea consumption and risk of ischaemic heart disease (IHD) according to types of tea and years of tea consumption
| Never | Less than daily* | Daily | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Subgroups | No. of cases | Cases/person-years (1/1000) | HR | No. of cases | Cases/person-years (1/1000) | HR (95% CI) | No. of cases | Cases/person-years (1/1000) | HR (95% CI) |
| IHD | 10 013 | 8.36 | 1.00 | ||||||
| Type of tea | |||||||||
| Green tea | 1363 | 6.58 | 0.99 (0.93–1.05) | 5690 | 7.38 | 0.91 (0.87 –0.95) | |||
| Non-green tea | 203 | 4.46 | 0.92 (0.79 –1.06) | 696 | 5.32 | 0.89 (0.81–0.98) | |||
| Years of tea consumption | |||||||||
| ≤10 | 507 | 5.38 | 0.95 (0.86–1.04) | 1079 | 6.52 | 0.96 (0.90 –1.03) | |||
| 11–30 | 613 | 5.19 | 1.01 (0.93 –1.10) | 2242 | 5.01 | 0.91 (0.86 –0.97) | |||
| ≥31 | 446 | 11.02 | 0.94 (0.85 –1.04) | 3065 | 10.62 | 0.84 (0.79 –0.90) | |||
| MCE | 1518 | 1.24 | 1.00 | ||||||
| Type of tea | |||||||||
| Green tea | 224 | 1.06 | 0.99 (0.85 –1.16) | 1123 | 1.43 | 0.91 (0.81 –1.01) | |||
| Non-green tea | 38 | 0.82 | 1.07 (0.75 –1.53) | 126 | 0.95 | 1.03 (0.81 –1.32) | |||
| Years of tea consumption | |||||||||
| ≤10 | 74 | 0.78 | 0.97 (0.76–1.24) | 194 | 1.15 | 1.01 (0.86–1.19) | |||
| 11–30 | 98 | 0.82 | 1.07 (0.85 –1.33) | 372 | 0.82 | 0.88 (0.76 –1.01) | |||
| ≥31 | 90 | 2.16 | 0.93 (0.73 –1.18) | 683 | 2.31 | 0.87 (0.75 –1.00) | |||
Multivariate HRs are calculated using Cox proportional hazard model with adjustment for age (years), sex (male or female), level of education (no formal school, primary school, middle school, high school, college, or university or higher), marital status (married, widowed, divorced or separated, or never married), alcohol consumption (never; occasional; former and having quitted ≤2, 3–4 or ≥5 years; weekly consuming 1–286, 287–426 or ≥427 g of alcohol for men or 1–146, 147–286 or ≥287 g of alcohol for women), smoking status (never; occasional; former and having quitted ≤2, 3–4, 5–9, 10–19 or ≥20 years; current smoking 1–4, 5–9, 10–14, 15–19, 20–24 or ≥25 cigarettes/day), physical activity (MET hour/day), intake frequencies of red meat, fruits and vegetables (daily, 4–6 days/week, 1–3 days/week, monthly, or rarely or never), family history heart attack (presence, absence or unknown), body mass index, prevalent hypertension and diabetes at baseline (presence or absence).
*Excluded 153 120 participants who reported their tea consumption as ‘only occasionally, only at certain seasons or monthly but less than weekly’ and whose information on commonly consumed tea type or years of tea consumption was not collected.
MCE, major coronary events; MET, metabolic equivalent task.