Table 1.
Characteristics of included epidemiological studies on chewing substances and risk of CVD
| Study | Geographical region, gender, recruitment, follow-up, No. of participants | Study design | Exposure | Outcome | Definition and ascertainment | No. of cases or deaths# | RR (95% CI) | Adjustment factors |
| Teo et al., 2006 | Mainly South Asia, both sexes, 1999–2003, NR, 27 098 | Case-control | Chewing tobacco | Acute myocardial infarction | Characteristic manifestation and ECG (specific criteria available) | NA | 2.23 (1.41–3.52) | Age, gender, diabetes, abdominal obesity, hypertension, exercise, diet |
| Wen et al., 2005 | Taiwan (China), men, 1982–1992, 1982–2000, 19 719 | Cohort | Betel quid | CVD [390–459], IHD [410–414], stroke [430–438] | ICD-9, death registry system | 275/39/86 | 1.1 (0.8–1.6), 1.0 (0.5–2.4), 1.3 (0.8–2.2) | Age, alcohol, education |
| Gupta et al., 2005 | India, both sexes, 1992–1994, 1992–1999, 97 244 | Cohort | Betel quid, areca nut, mishri | CVD [I00–I99], IHD [I10, I11, I13, I21, I24, I25, I46, I50], CBVD [I61–I64, I66, I67] | ICD-10, death registry system | 1876/1372/386 | 1.06 (0.84–1.33)*, 1.05 (0.76–1.47)*, 1.23 (0.97–1.55)* | Age, education |
| Rahman and Zaman, 2008 | Bangladesh, both sexes, 2006–2007, NR, 207 | Case-control | Betel quid, dried tobacco leaf | Coronary heart disease (acute myocardial infarction and angina pectoris) | Clinical findings and ECG | NA | 2.8 (1.1–7.3) | Gender, age, hypertension |
| Yen et al., 2008 | Taiwan (China), men, 1999–2004, duration (2.81±1.50) years, 21 906 | Cohort | Betel quid | CVD [402, 410–414, 425–428, 430–438, 440–448] | ICD-9, incidence identified in hospital, mortality by registry system | 3163 | 1.24 (1.11–1.39) | Age, education, occupation, smoking, alcohol, intake of fish, milk, coffee, physical activity, family history |
| Lan et al., 2007 | Taiwan (China), both sexes, 1989–2003; 1996–2003, 6511 | Cohort | Betel quid | CVD [390–459], IHD [410–414], CBVD [430–438] | ICD-9, death registry system | 684/153/305 | 1.41 (1.12–1.77), 1.22 (0.73–2.04), 1.66 (1.19–2.30) | Gender, age, living area, hypertension, anemia, heart disease, liver disease, arthritis, physical difficulty, smoking, alcohol |
| Lin et al., 2008 | Taiwan (China), men, 1998–1999, 998–2005, 56 116 | Cohort | Betel quid | CVD [390–459] | ICD-9, death registry system | 309 | 1.77 (1.31–2.40)* | Age, BMI, diabetes, hypertension, cholesterol, triglyceride, alcohol, smoking, physical activity, income, education |
| Guh et al., 2007 | Taiwan (China), both sexes, 1993–1996, NR, 1932 | Cross-sectional | Betel quid | Heart disease | Questionnaires on self-report | NA | 1.34 (1.12–1.62)* | Age, abdominal obesity, cholesterol, hypertension, diabetes, smoking, fruit intake |
#
Number of cases or deaths from a certain outcome, cardiovascular disease (CVD), ischemic heart disease (IHD), cerebrovascular disease (CBVD), etc. (listed in order in the fifth column). Cases or deaths of non-chewing smokers were not included. The numbers are listed in the same order to accompany their corresponding outcomes
*
Results of meta-analysis
RR: relative risk; CI: confidence interval; NR: not relevant; NA: not available; ECG: electrocardiograph, ICD: international classification code; BMI: body mass index