Correlation between tea consumption and prevalence of hypertension among Singaporean Chinese residents aged ⩾40 years

The association between tea consumption and blood pressure in the adult population in Southwest China

OBJECTIVES

Prior research on the effect of tea consumption on blood pressure (BP) generated inconsistent findings. The objective of this study was to explore the effects of different types of tea consumption on BP.

METHODS

We included 76,673 participants aged 30-79 from the baseline data of the China Multi-Ethnic Cohort (CMEC) study. Binary logistic regression was used to analyze the influences of different types of tea consumption on the risk of hypertensive BP. Moreover, multiple linear regression was used to examine the association between tea drinking and BP.

RESULTS

Tea consumption was associated with a reduced risk of hypertensive BP by 10% (AOR: 0.90, 95%CI: 0.86-0.94). While dark tea was related to a 1.79-5.31 mmHg reduction in systolic blood pressure (SBP) and a 0.47-1.02 mmHg reduction in diastolic blood pressure (DBP), sweet tea, regardless of the duration, frequency, or amount of consumption, significantly was associated with a reduced SBP by 3.19-7.18 mmHg. Green tea also was associated with a reduced SBP by 1.21-2.98 mmHg. Although scented tea was related to reduced SBP by 1.26-2.48 mmHg, the greatest effect came from the long duration (> 40 years:β=-2.17 mmHg, 95%CI=-3.47 mmHg --0.87 mmHg), low frequency (1-2 d/w: β = -2.48 mmHg, 95%CI=-3.76 mmHg--1.20 mmHg), and low amount (≤ 2 g/d: β=-2.21 mmHg, 95%CI=-3.01 mmHg--1.40 mmHg). Additionally, scented tea was correlated to a decrease in DBP at the frequency of 1-2 d/w (β=-0.84 mmHg, 95%CI=-1.65 mmHg--0.02 mmHg). Drinking black tea only was associated with lowered SBP. The protective effect of black tea on SBP was characterized by the long-duration (> 15 years, -2.63--5.76 mmHg), high frequency (6-7 d/w, -2.43 mmHg), and medium amount (2.1-4.0 g/d, -3.06 mmHg).

CONCLUSION

Tea consumption was associated with lower SBP and a reduced risk of hypertensive BP. The antihypertensive effect varies across types of tea consumed.

Association between the prudent dietary pattern and blood pressure in Chinese adults is partially mediated by body composition

High blood pressure or hypertension is one of the major risks of cardiovascular disease, which is the leading cause of death in China. This study aimed to assess the relationship between dietary patterns and blood pressure among Chinese adults. Using factor analysis of 66-item food frequency questionnaire to identify dietary patterns. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured according to standardized guidelines. Multivariate linear regressions were performed in 6849 Chinese adults (46.5% female) aged 21-70 years considering sociodemographic characteristics, lifestyle behaviors, and anthropometry data. The vegetable-rich pattern, animal-food pattern, and prudent dietary pattern were identified. After adjustment for potential confounders including age, gender, alcohol consumption, smoking status, energy intake, and physical activity, only prudent dietary pattern was negatively related to SBP (β = -2.30, p for trend =0.0003) and DBP (β = -1.44, p for trend =0.0006). Body mass index, waist circumstance and body fat percentage explained, respectively, 42.5%/47.8, 14.8%/17.6 and 26.0%/29.1% of the association between prudent pattern and SBP/DBP in mediation analysis. There were no association were observed between other dietary patterns and blood pressure. In conclusion, Prudent dietary pattern was associated with lower SBP and DBP among Southwest Chinese and this association was partially explained by body composition.

Tea Consumption Is Associated with Reduced Cognitive Decline and Interacts with Iron Intake: A Population-Based Longitudinal Study on 4,820 Old Adults

Background: Previous studies suggest a positive effect of tea intake on cognition. Additional micronutrients that may moderate this association was not previously examined. Objective: To examine the association between tea consumption and cognition and explore the interaction between tea consumption and iron intake. Methods: Data from the China Health and Nutrition Survey between 1997 and 2011 was used. 4,820 individuals (≥55 years) were included in the analyses. Measurement of cognitive function was conducted in 1997, 2000, 2004, and 2006. Tea consumption was self-reported. Food intake was assessed by 24-hour dietary recalls of three consecutive days during home visits between 1997 and 2011. Multivariable mixed linear regression and logistic regression was used to assess the association. Results: Tea consumption was associated with reduced global cognitive function decline. In fully adjusted models, regression coefficients (95% CIs) for those who consumed 0 cups/day,<2 cups/day, 2–3.9 cups/day, and≥4 cups/day of tea were 0, –0.09 (–0.55–0.37), 0.05 (–0.34–0.45), and 0.87 (0.46–1.29), respectively. This effect was stronger in adults > 60 years. Tea consumption of≥4 cups/day was inversely associated with self-reported poor memory (OR 0.70 (95% CI 0.56–0.86)) and memory decline (OR, 0.73 (95% CI 0.62–0.87)). There was a significant interaction between tea consumption and iron intake in relation to cognition. High iron intake was inversely associated with cognition in non-consumers of tea but not in tea consumers. Conclusion: Higher tea intake is associated with reduced cognitive decline in adults and inhibits the adverse effect of high iron intake.

Sex differences in the association between green tea consumption and hypertension in elderly Chinese adults

BACKGROUND

Green tea has been one of the most popular beverages in China since ancient times. Mixed results concerning the effect of green tea consumption on the incidence of hypertension have been published over the past decades. However, no previous studies have focused on longevous individuals in China and the sex differences in the association between habitual green tea intake and hypertension.

METHODS

The data extracted from the database of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) in 2018 were used for a secondary analysis. Logistic regression models were employed to examine the odds ratio (OR) of daily green tea consumption on the incidence of hypertension by sex.

RESULTS

A total of 9277 individuals were included in the analysis (39.8% were men). The included individuals had a mean age of 80.9 and 84.8 years for those who drank green tea daily and those who had never, respectively (p <  0.001). The incidence of hypertension varied at baseline according to green tea drinking habit and sex. For women who had a habitual green tea intake or had never drunk green tea, the incidence of hypertension was 47.3 and 43.9%, respectively (p = 0.241), whereas it was 51.6 and 39.7% for men (p <  0.001). After adjusting for potential confounders, a 38% increase in the risk of hypertension was observed in men who consumed green tea daily (OR, 1.38; 95% CI, 1.15-1.67; p <  0.001).

CONCLUSIONS

Chinese longevous men had a 38% higher risk of developing hypertension when drinking green tea daily. However, no effect of green tea consumption on the incidence of hypertension in women was found. More attention should be paid to the lifestyle of longevous individuals for health promotion, and a sex-specific approach to deliver care for very elderly people is warranted.

Health-related quality of life of middle-aged and elderly people with hypertension: A cross-sectional survey from a rural area in China

OBJECTIVE

To evaluate health-related quality of life (HRQoL) of middle-aged and elderly people with hypertension in Enshi, China, and to explore the important correlates defining HRQoL.

METHODS

From April through July 2018, a self-monitoring intervention program for hypertension control was implemented in a remote area of central China. Participants completed a cross-sectional survey which included demographic characteristics, the Health-related Quality of Life Survey, and the Pittsburgh Sleep Quality Index Survey. Univariate analysis was performed by analysis of variance, and multiple linear regression analysis was used to analyze the influencing factors of HRQoL in middle-aged and elderly hypertensive patients. In the multivariate analysis, the variables with P≤0.05 in the single factor analysis were combined with the professional significance to establish a multiple linear regression model.

RESULTS

Information from 500 participants was available for analysis. Among them, the scores of PCS and MCS was 31.66 ± 9.50 and 41.38 ± 10.69, respectively. Multivariable regression analyses showed that higher education and sleep quality, and moderate physical activity (30 minutes for at least five days a week) had a positive influence on PCS scores. Higher monthly family income (3,000-5,000 ¥) and sleep quality, regular tea-drinking, having 30 minutes of moderate physical activity at least five days a week were positively associated with MCS scores.

CONCLUSION

The overall HRQoL for rural middle-aged and elderly hypertensive patients in Xuan'en county of Hubei province was poor. Effective relevant measures for the above factors were urgently needed to improve the quality of life for the elderly in rural areas. Awareness of these relevant factors could help health care professionals provide better supportive care.

Associations between habitual tea consumption and 5-year longitudinal changes of systolic blood pressure in older Chinese

BACKGROUND AND OBJECTIVES

Tea consumption may contribute to the management of blood pressure; however, evidence from longitudinal studies is lacking. This study aimed to examine the relationship between habitual tea consumption and trajectories of systolic blood pressure in a community-based sample of Chinese adults aged 60 years or older.

METHODS

A prospective cohort of 3870 participants was investigated from 2014 to 2018. Trajectories of systolic blood pressure were identified using latent mixture modeling with the Proc Traj procedure. Multiple logistic regression models were fitted to explore associations between tea consumption habits and trajectories of systolic blood pressure.

RESULTS

In the overall sample, participants were less likely to be habitual tea drinkers if they were in the "moderate-stable" (144.4-149.9 mm Hg), "moderate-increasing" (157.2-180.0 mm Hg), and "elevated-increasing" (184.7-209.8 mm Hg) groups as compared to those in the "low-stable" group (125.3-130.0 mm Hg). The "elevated-decreasing" group (170.7 - 167.2 mmHg) consistently showed no significant difference in the likelihood of habitual tea drinking as compared to the "low-stable" group.

CONCLUSIONS

This community-based prospective study indicated that habitual tea consumption was associated with relatively favorable long-term systolic blood pressure statuses.

The effects of regular consumption of green or black tea beverage on blood pressure in those with elevated blood pressure or hypertension: A systematic review and meta-analysis

OBJECTIVE

As a popular beverage, there has been much interest in studying the effects of tea intake on hypertension (HTN), a particular risk factor for cardiovascular disorders (CVDs). We have thus aimed to isolate the randomized controlled trials investigating the efficacy of black or green tea as a beverage in subjects with elevated blood pressure (BP), or HTN.

METHODS

PubMed, Scopus, Web of Science, and ProQuest dissertations and theses databases were searched from February 1, 1995, up to July 20, 2019, to identify relevant studies.

RESULTS

The search strategy generated 1119 trials, of which finally five trials fulfilled the criteria for being included in the current study. Three out of 5 articles showed a low risk of bias. According to nine measurements derived from 5 trials on 408 individuals, it was found that regular tea intake resulted in the reduction in SBP (weighted mean difference (WMD): -4.81 mmHg, 95 %CI: -8.40 to -1.58, P = .004) and DBP (WMD:-1.98 mmHg, 95 %CI: -3.77 to -0.20, P = .029); however, excluding the most heterogeneous trials showed that regular tea intake might reduce SBP and DBP by about -3.53 and -0.99 mmHg, respectively. Based on meta-regression findings, we found the longer the duration of tea intake (≥3months), the higher the decrease in both SBP and DBP. Categorized studies, according to the tea type, revealed that the hypotensive effects of green tea were more pronounced compared to black tea. None of the studies reported any side effects.

CONCLUSION

These results suggest the positive effects of regular tea intake on BP in subjects with elevated BP or HTN. Hence, it may be applicable to physicians, health care providers, and particularly HTN patients.

Chemistry and Biological Activities of Processed Camellia sinensis Teas: A Comprehensive Review

Tea is a typical processed beverage from the fresh leaves of Camellia sinensis [Camellia sinensis (L.) O. Kuntze] or Camellia assamica [Camellia sinensis var. assamica (Mast.) Kitamura] through different manufacturing techniques. The secondary metabolites of fresh tea leaves are mainly flavan-3-ols, phenolic acids, purine alkaloids, condensed tannins, hydrolysable tannins, saponins, flavonols, and their glycoside forms. During the processing, tea leaves go through several steps, such as withering, rolling, fermentation, postfermentation, and roasting (drying) to produce different types of tea. After processing, theaflavins, thearubigins, and flavan-3-ols derivatives emerge as the newly formed compounds with a corresponding decrease in concentrations of catechins. Each type of tea has its own critical process and presents unique chemical composition and flavor. The components among different teas also cause significant changes in their biological activities both in vitro and in vivo. In the present review, the progress of tea chemistry and the effects of individual unit operation on components were comprehensively described. The health benefits of tea were also reviewed based on the human epidemiological and clinical studies. Although there have been multiple studies about the tea chemistry and biological activities, most of existing results are related to tea polyphenols, especially (-)-epigallocatechin gallate. Other compounds, including the novel compounds, as well as isomers of amino acids and catechins, have not been explored in depth.

Association between tea consumption and risk of cognitive disorders: A dose-response meta-analysis of observational studies

Background

The epidemiological evidence for a dose-response relationship between tea consumption and risk of cognitive disorders is sparse. The aim of the study was to summarize the evidence for the association of tea consumption with risk of cognitive disorders and assess the dose-response relationship.

Methods

We searched electronic databases of Pubmed, Embase, and Cochrane Library (from 1965 to Jan 19, 2017) for eligible studies that published in the international journals. A random-effects model was used to pool the most adjusted odds ratios (ORs) and the corresponding 95% confidence intervals (CIs).

Results

Seventeen studies involving 48,435 participants were included in our study. The meta-analysis showed that a higher tea consumption was associated with a significant reduction in the risk of cognitive disorders (OR=0.73, 95% CI: 0.65-0.82). When considering the specific types of tea consumption, the significantly inverse association is only found in green tea consumption (OR=0.64, 95% CI: 0.53-0.77) but not in black/oolong tea consumption (OR=0.75, 95% CI: 0.55-1.01). Dose-response meta-analysis indicated that tea consumption is linearly associated with a reduced risk of cognitive disorders. An increment of 100 ml/day, 300 ml/day, and 500 ml/day of tea consumption was associated with a 6% (OR=0.94, 95% CI: 0.92-0.96), 19% (OR=0.81, 95% CI: 0.74-0.88), and 29% (OR=0.71, 95% CI: 0.62-0.82) lower risk of cognitive disorders.

Conclusions

Tea consumption is inversely and linearly related to the risk of cognitive disorders. More studies are needed to further confirm our findings.

Dietary patterns associated hyperuricemia among Chinese aged 45 to 59 years: An observational study

In our literature research, we have not found any study reporting the association between the major dietary patterns and the risk of hyperuricemia in a middle-aged Chinese population. Herein, the present study aimed to evaluate the association of dietary patterns with the risk of hyperuricemia in the city of Hangzhou, Zhejiang Province, East China. We included 1204 participants (743 males and 461 females) aged 45 to 59 years in the present cross-sectional study. Dietary intake was assessed using a semiquantitative food frequency questionnaire in 2014 to 2016. All biochemical data and anthropometric measurements were collected following standardized procedures. Dietary patterns were determined by using factor analysis. We examined the associations between major dietary patterns and hyperuricemia risk by log-binominal regression analysis, and the results are presented as prevalence ratio (PR) and confidence interval (CI). Three major dietary patterns were identified by means of factor analysis: traditional Chinese, meat food, and mixed food patterns. After controlling for potential confounders, subjects in the highest quartile of the traditional Chinese pattern scores had a lower PR for hyperuricemia (PR = 0.82; 95%CI: 0.426-0.922), in comparison to those from the lowest quartile, while compared with the lowest quartile of the meat food pattern, the highest quartile had a greater PR for hyperuricemia (PR = 1.48; 95%CI: 1.120-2.097). Besides, no association was observed between mixed food pattern and the risk of hyperuricemia.Our findings indicate that the traditional Chinese pattern is associated with a decreased risk of hyperuricemia, and the meat food pattern is associated with an increased risk of hyperuricemia, whereas the mixed food pattern shows no association with the risk of hyperuricemia. Further large prospective studies are warranted to confirm our findings.

Blood Pressure Is Associated with Tea Consumption: A Cross-sectional Study in a Rural, Elderly Population of Jiangsu China

OBJECTIVES

Tea has long been hypothesized to possess hypotensive effects. However, there is uncertainty regarding the association of tea consumption with arterial blood pressure (BP). We aimed to examine the association between tea consumption and BP components including systolic BP (SBP) and diastolic BP (DBP).

DESIGN

Community-based, cross-sectional study of Suzhou City, Jiangsu Province, China.

SETTING

Tea consumption has protective influence on BP and presence of hypertension.

PARTICIPANTS

4579 older adults aged 60 years or older from the Weitang Geriatric Diseases study.

MEASUREMENTS

Detailed information regarding tea consumption was collected using a pre-designed questionnaire. BP components were measured at least 3 times with a minimum 5-minute interval, by well-trained research nurses.

METHODS

Data of 4579 older adults (response rate: 82%) aged 60 years or older from the Weitang Geriatric Diseases study were included in the analysis and we estimated the relationship of tea consumption and BP using linear regression models and the association between tea consumption and risk of hypertension using logistic regression models.

RESULTS

In linear regression models, higher tea consumption frequency was found to be associated with lower systolic BP values, after adjusting for the effect of age, sex, education level, lifestyle-related factors, and cardiometabolic confounding factors in overall (coefficient =-1.49, P=0.0003), normotensive (coefficient =-0.91, P=0.017) and participants without anti-hypertensive treatment (coefficient =-1.26, P=0.027). Significant inverse association between diastolic BP and frequency of tea consumption was also observed in the overall subjects (coefficient =-0.74, P=0.003). In multivariate logistic analyses, habitual tea drinking was inversely associated with presence of hypertension [odds ratio (OR)=0.79, P=0.011] , and there was a progressive reduction in risk associated with higher frequency of tea consumption (P for trend=0.011).

CONCLUSION

Habitual tea consumption was found to be associated with lower values of components of BP and a reduced likelihood of having hypertension in older adults. Given the widespread consumption of tea throughout China and the world, together with the major cardiovascular disease risk, our findings have important implications for human health.