Tea Consumption and Ischemic Stroke Risk: A Case―Control Study in Southern China

• Published in: Stroke (1970) Vol. 40; no. 7; pp. 2480 - 2485
• Main Authors: WENBIN LIANG, LEE, Andy H, BINNS, Colin W, RONGSHENG HUANG, DELONG HU, QINGKUN ZHOU
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01.07.2009
• Subjects: Aged; Aged, 80 and over; Biological and medical sciences; Case-Control Studies; China - epidemiology; Dose-Response Relationship, Drug; Female; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Health Surveys; Humans; Male; Medical sciences; Middle Aged; Nervous system (semeiology, syndromes); Neurology; Reproducibility of Results; Risk Factors; Stroke - epidemiology; Stroke - ethnology; Stroke - prevention & control; Tea; Vascular diseases and vascular malformations of the nervous system; Asia; China; Cerebral infarction; Stroke; Nervous system diseases; green tea; Cardiovascular disease; Case control study; Epidemiology; Cerebral disorder; Vascular disease; Prevention; case-control study; Central nervous system disease; Risk factor; Brain ischemia; stroke risk; Cerebrovascular disease
• ISSN: 0039-2499; 1524-4628
• DOI: 10.1161/STROKEAHA.109.548586

Although experimental studies have suggested that tea consumption may reduce the risk of ischemic stroke, available epidemiological evidence is equivocal, mainly due to the lack of accurate measurements on tea exposure. This study aims to ascertain the relationship between tea drinking and ischemic stroke risk. A case-control study was conducted in southern China from 2007 to 2008. A total of 374 patients with incident ischemic stroke and 464 control subjects (mean age, 69 years) were recruited from 3 hospitals in Foshan. Information on frequency and duration of tea drinking, quantity of dried tea leaves, and types of tea consumed, together with habitual diet and lifestyle characteristics, was obtained from participants using a validated and reliable questionnaire. Logistic regression analyses were performed for tea consumption variables accounting for confounders that affect the ischemic stroke risk. A significant decrease in ischemic stroke risk was observed for drinking at least one cup of tea weekly (P=0.015) when compared with infrequent or nondrinkers, the risk reduction being largest by drinking one to 2 cups of green or oolong tea daily. Significant inverse dose-response relationships were also found for years of drinking and the amount of dried tea leaves brewed. The adjusted ORs for the highest level of consumption in terms of frequency of intake, duration of drinking, and average tea leaves brewed were 0.61 (95% CI, 0.40 to 0.94), 0.40 (95% CI, 0.25 to 0.64), and 0.27 (95% CI, 0.16 to 0.46), respectively. Long-term tea consumption is associated with reduced risk of ischemic stroke.