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

Effects of green tea on lipid profile in overweight and obese women

The effect of green tea administration on serum lipids' concentrations remains unclear as various investigations, which have explored this topic, have produced conflicting results. Gender might be one of the factors influencing the impact of green tea on the lipid profile. Hence, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the effect of green tea intake on the lipid profile in overweight and obese women. We searched five databases (Web of Science, SCOPUS, Embase, PubMed/Medline, and Google Scholar) using a combination of MeSH and non-MeSH terms. Results were expressed as weighted mean differences (WMDs) and 95% confidence intervals (CIs) and synthesized with a random-effects model. In total, 15 eligible RCTs with 16 arms (1818 participants) were included in the meta-analysis. The combined effect size revealed a significant reduction in total cholesterol (TC) (WMD: -4.45 mg/dl, 95% CI: -6.63, -2.27, P<0.001) and low-density lipoprotein cholesterol (LDL-C) (WMD: -4.49 mg/dl, 95% CI: -7.50 to -1.47, P=0.003) concentrations following green tea supplementation in overweight and/or obese women. In addition, a more pronounced reduction of triglyceride (TG) levels occurred when the baseline TG value was ≥150 mg/dL (WMD: -24.45 mg/dL, 95% CI: -40.63 to -8.26, P=0.003). Moreover, a significant decrease in TG concentrations occurred in RCTs conducted on overweight subjects (BMI: 25-29.99 kg/m2) (WMD: -5.88 mg/dl, 95% CI: -10.76 to -0.99, P=0.01). In the subgroup analyses based on the study population, a notable increase in high-density lipoprotein cholesterol (HDL-C) values was observed in obese individuals (>30 kg/m2) (WMD: 2.63 mg/dl, 95% CI: 0.10 to 5.16, P=0.041). Consumption of green tea causes a reduction in LDL-C and TC concentrations in overweight and obese women. The decline in TG levels was notable particularly in overweight patients with hypertriglyceridemia at baseline. In addition, a significant increase in HDL-C was detected in obese subjects following intake of green tea.

Association of frailty status with overall survival in elderly hypertensive patients: based on the Chinese Longitudinal Healthy Longevity Survey

BACKGROUND

Hypertension and frailty often coexist in older people. The present study aimed to evaluate the association of frailty status with overall survival in elderly hypertensive patients, using data from the Chinese Longitudinal Healthy Longevity Survey.

METHODS

A total of 10,493 elderly hypertensive patients were included in the present study (median age 87.0 years, 58.3% male). Frailty status was assessed according to a 36-item frailty index (FI), which divides elderly individuals into four groups: robustness (FI ≤ 0.10), pre-frailty (0.10 < FI ≤ 0.20), mild-frailty (0.20 < FI ≤ 0.30), and moderate-severe frailty (FI > 0.30). The study outcome was overall survival time. Accelerated failure time model was used to evaluate the association of frailty status with overall survival.

RESULTS

During a period of 44,616.6 person-years of follow-up, 7327 (69.8%) participants died. The overall survival time was decreased with the deterioration of frailty status. With the robust group as reference, adjusted time ratios (TRs) were 0.84 (95% confidence interval [CI]: 0.80-0.87) for the pre-frailty group, 0.68 (95% CI: 0.64-0.72) for the mild frailty group, and 0.52 (95% CI: 0.48-0.56) for the moderate-severe frailty group, respectively. In addition, restricted cubic spline analysis revealed a nearly linear relationship between FI and overall survival (p for non-linearity = 0.041), which indicated the overall survival time decreased by 17% with per standard deviation increase in FI (TR = 0.83, 95% CI: 0.82-0.85). Stratified and sensitivity analyses suggested the robustness of the results.

CONCLUSIONS

The overall survival time of elderly hypertensive patients decreased with the deterioration of frailty status. Given that frailty is a dynamic and even reversible process, early identification of frailty and active intervention may improve the prognosis of elderly hypertensive patients.

Dietary factors and hypertension: A Mendelian randomization analysis

This research explores the causal link between dietary habits and hypertension through Mendelian randomization, providing distinct perspectives on the role of diet in addressing this worldwide health issue. Utilizing instrumental variables, we applied advanced statistical methods, including the weighted median, inverse variance weighted, and MR-Egger, to evaluate the impact of 17 dietary elements on hypertension. These elements ranged across various food groups, such as fruits, meats, vegetables, and beverages, both alcoholic and nonalcoholic. Our results identified a significant positive association of hypertension with weekly alcohol consumption (OR 1.340 [95%CI 1.0001 to 1.794], p = .0499) and poultry intake (OR 2.569 [95%CI 1.305 to 5.057], p = .00631). Conversely, a negative association was observed with lamb/mutton (OR 0.550 [95%CI 0.343 to 0.881], p = .0129), cheese (OR 0.650 [95%CI 0.519 to 0.813], p = .000159), tea (OR 0.797 [95%CI 0.640 to 0.993], p = .0433), cereal (OR 0.684 [95%CI 0.494 to 0.948], p = .0227), and dried fruit consumption (OR 0.492 [95%CI 0.343 to 0.707], p = .000127). These findings suggest that dietary modifications, such as increasing consumption of specific foods like cheese, lamb/mutton, tea, cereals, and dried fruits, could potentially reduce hypertension risk while reducing intake of alcoholic beverages and poultry might mitigate its increase. No direct causal relationships were established between other dietary factors and hypertension. The study highlights the importance of specific dietary modifications for the prevention and control of hypertension, making a substantial contribution to public health tactics and recommendations.

Association between tea types and number of teeth: a cross-sectional study of the Chinese Longitudinal Healthy Longevity Survey

BACKGROUND

Previous studies have suggested that tea consumption may have a positive impact on oral health. However, the effects of different tea types on oral health remain unclear. Therefore, this study aimed to determine the association between residual teeth and consumption habits of different types of tea (green tea, black tea, oolong tea, and scented tea) in older adults.

METHODS

We conducted a secondary analysis using data from the Chinese Longitudinal Healthy Longevity Survey in 2018. In a sample of 6,387 older adults, we performed logistic regression analysis to examine the relationship between persistent tea consumption and oral health according to sex and brushing frequency. The indices for particularly healthy oral health and relative health were set at more than 20 teeth and more than 10 teeth, respectively.

RESULTS

The study included 2,725 males and 3,662 females, both aged 65 and older. Among individuals with more than 20 teeth, drinking green tea significantly improved oral health in men (adjusted odds ratio [ORs]: 1.377; 95% confidence interval [CI]: 1.082-1.752) and drinking black tea significantly improved the oral health of women (ORs: 2.349, 95%CI: 1.028-5.366). In the daily brushing group, green tea had a significant beneficial effect on increasing the number of teeth in men and black tea had a significant beneficial effect in women. Among individuals with more than 10 teeth, drinking green tea significantly improved oral health in men (ORs: 1.539; 95% CI: 1.209-1.959) and drinking green tea and scented tea significantly improved the oral health of women (ORs: 1.447, 95%CI: 1.052-1.991; ORs: 1.948, 95%CI: 1.137-3.340). In the daily brushing group, consumption of green tea and black tea had significant beneficial effects on increasing the number of teeth in men, whereas that of green tea, black tea, and scented tea had significant beneficial effects in women.

CONCLUSION

Long-term green tea consumption in males and black tea consumption in females were significantly associated with maintaining functional dentition (≥20 teeth). Similarly, long-term green tea consumption in males and green tea and scented tea consumption in females were associated with avoiding severe tooth loss (≥10 teeth). Furthermore, in the daily tooth brushing group, long-term consumption of black tea was associated with avoiding severe tooth loss in both sexes. However, tea consumption alone had no effect on oral health without good brushing habits.

The Association Between Habitual Tea Consumption and Frailty Transition in Community-Dwelling Older Adults: A Prospective Cohort Study

OBJECTIVES

To investigate the association between habitual tea consumption and transitions between frailty states among older adults in China.

DESIGN

A prospective cohort study based on the Chinese Longitudinal Healthy Longevity Study.

SETTING AND PARTICIPANTS

A total of 23,720 older adults aged ≥65 years with complete data regarding frailty status and tea consumption were recruited.

METHODS

The frequency and consistency of tea consumption were introduced to evaluate levels of tea consumption. The frailty index was used to define frailty status (frail and nonfrail). Frailty transition was classified into remaining nonfrail, improvement, worsening, and remaining frail groups. Logistic regression models were applied.

RESULTS

The overall frailty prevalence at baseline was 19.1%, being lower among consistent daily tea drinkers (12.5%) and higher among non-tea drinkers (21.9%). Logistic regression analyses showed that the risk of frailty was significantly reduced among consistent daily tea drinkers after adjusting for all confounders [odds ratio (OR), 0.81; 95% CI, 0.67-0.98]. During the 3-year follow-up, improvement in frailty status was more common among consistent daily tea drinkers (50.9%) than non-tea drinkers (40.9%), and this trend was opposite in participants with worsened frailty status (consistent daily tea drinkers: 12.2%) vs non-tea drinkers: 19.2%). Further analysis showed that consistent daily tea drinkers were significantly associated with improvement in frailty status (OR, 3.24; 95% CI, 1.02-10.31) and remaining in a nonfrail state (OR, 1.35; 95% CI, 1.00-1.83). In addition, daily tea consumption was observed to be positively associated with remaining in a nonfrail state and inversely associated with worsened frailty status in men, but not in women.

CONCLUSIONS AND IMPLICATIONS

Older people consuming tea daily tend to have an improved frailty status in the future. Men with daily tea consumption were less likely to have a worsened frailty status. Advocating for the traditional lifestyle of drinking tea could be a promising way to advance healthy aging for older adults.

Associations between tea-drinking habits and health-related quality of life in Chinese adults: a mediation analysis based on sleep quality

BACKGROUND

The aim of this study was to explore the association between tea-drinking habits and health-related quality of life (HRQoL) in Chinese adults and the mediating effect of sleep quality in this association.

METHODS

Data were derived from the 2020 Survey of Social Factors for Chronic Disease Prevention and Control among adults in Lishui District, Nanjing, Jiangsu Province, China. Tea-drinking habits were measured by participants' self-report. The HRQoL was measured using the 12-item Short Form Health Survey. Multiple linear regression modelling and mediating effects modelling were used for analyses.

RESULTS

Habitual tea drinking, frequent tea drinking (drinking tea 6-7 days per week), tea concentration and <10 g of tea per day were strongly associated with an increase in HRQoL among Chinese adults (all p<0.05). The association between tea-drinking habits and HRQoL among Chinese adults was more pronounced in the male population and in those ≥45 y of age (all p<0.05). Tea drinking habits may improve HRQoL in Chinese adults by enhancing sleep quality (all p<0.05).

CONCLUSIONS

Maintaining the habit of habitual tea drinking (6-7 days per week), in small amounts (<10 g tea per day) was conducive to improving HRQoL of Chinese adults by improving sleep quality.

Therapeutic Activity of Green Tea Epigallocatechin-3-Gallate on Metabolic Diseases and Non-Alcoholic Fatty Liver Diseases: The Current Updates

Green tea polyphenols have numerous functions including antioxidation and modulation of various cellular proteins and are thus beneficial against metabolic diseases including obesity, type 2 diabetes, cardiovascular and non-alcoholic fatty liver diseases, and their comorbidities. Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenol in green tea and is attributed to antioxidant and free radical scavenging activities, and the likelihood of targeting multiple metabolic pathways. It has been shown to exhibit anti-obesity, anti-inflammatory, anti-diabetic, anti-arteriosclerotic, and weight-reducing effects in humans. Worldwide, the incidences of metabolic diseases have been escalating across all age groups in modern society. Therefore, EGCG is being increasingly investigated to address the problems. This review presents the current updates on the effects of EGCG on metabolic diseases, and highlights evidence related to its safety. Collectively, this review brings more evidence for therapeutic application and further studies on EGCG and its derivatives to alleviate metabolic diseases and non-alcoholic fatty liver diseases.

The Relationship between Beverages Consumption and Cognitive Impairment in Middle-Aged and Elderly Chinese Population

Some evidence shows that beverage consumption has an impact on cognitive performance. This is a follow-up study of dietary habits and cognitive function in the Chinese middle-aged and elderly population. The objective of this study was to explore the relationship between beverage consumption and cognitive impairment. The source and grouping of the participants can be seen in the previous article, "Study of Diet Habits and Cognitive Function in the Chinese Middle-Aged and Elderly Population: The Association between Folic Acid, B Vitamins, Vitamin D, Coenzyme Q10 Supplementation and Cognitive Ability". Among 892 participants, one-third (296) completed both Amyloid beta(Aβ)-PET and plasma biomarkers. The results showed that the consumption of beverages (green tea, coffee, pure milk) was a protective factor for cognitive impairment, daily water consumption <1500 mL (especially <500 mL) was a risk factor for cognitive impairment, and the above correlated with baseline cognitive status. The relationship of green tea, coffee, and pure milk consumption with cognitive impairment was related to gender. We also found that among the participants with Aβ deposition, the consumption of pure milk and green tea was associated with low levels of p-Tau-181. In conclusion, the relationship between beverage consumption and cognitive impairment in Chinese middle-aged and elderly adults may be related to baseline cognitive status, gender, and Aβ deposition.

Consumption frequencies of beverages and the hypertension risk in adults: a cohort study in China

OBJECTIVE

To explore the associations between the consumption frequencies of alcohol, tea and sugar-sweetened beverages (SSBs) and the hypertension risk among Chinese adults.

DESIGN

A longitudinal study of the effect of beverage consumption on hypertension risk.

SETTING

Nine provinces in China, including Jiangsu, Hubei, Hunan, Guangxi, Guizhou, Liaoning, Heilongjiang, Shandong and Henan.

PARTICIPANTS

The longitudinal data of the China Health and Nutrition Survey from 2004 to 2015 were used. A total of 4427 participants from 9 provinces were included at baseline.

OUTCOME

First incidence of hypertension.

RESULTS

During a mean follow-up of 8.7 years, 1478 participants developed hypertension. Alcohol consumption more than twice a week in young men (HR 1.86, 95% CI 1.09 to 3.18) or middle-aged men (HR 1.37, 95% CI 1.01 to 1.87) was associated with a higher hypertension risk. Middle-aged women who consumed tea frequently (HR 0.71, 95% CI 0.52 to 0.97), or young women who consumed SSBs less than once a week (HR 0.31, 95% CI 0.14 to 0.67) had a lower risk of hypertension.

CONCLUSIONS

High-frequency alcohol consumption increased the risk of hypertension in men, and frequent tea consumption and low-frequency SSBs consumption were associated with lower risk of hypertension in women. Consumption frequency of beverages was also suggested to be considered in the prevention and control of hypertension.

Green tea consumption and the risk of stroke: A systematic review and meta-analysis of cohort studies

OBJECTIVES

Epidemiologic studies are inconsistent regarding the association between green tea consumption and the risk of stroke. We performed a meta-analysis to determine whether an association exists between them in cohort studies.

METHODS

We searched the PubMed and Embase databases for studies conducted from 1966 through September 2022. Prospective cohort studies that provided relative risk (RR) estimates with 95% confidence interval (CI)s for the association were included. Study-specific risk estimates were combined by using a random-effects model.

RESULTS

A total of five studies, with 11 421 stroke cases among 645 393 participants, were included in the meta-analysis. The summary RR indicated a significant association between highest green tea consumption and reduced risk of stroke (summary RR: 0.74; 95% CI, 0.66-0.83). In the dose-response analysis, we observed a nonlinear association between green tea consumption and the risk of stroke (P for nonlinearity = 0.0000). Compared with non-consumers, the RRs (95% CI) of stroke across levels of green tea consumption were 0.91 (0.89-0.94) for 150 mL/d, 0.84 (0.80-0.89) for 300 mL/d, 0.79 (0.74-0.84) for 500 mL/d, 0.77 (0.72-0.82) for 900 mL/d, and 0.84 (0.77-0.91) for 1500 mL/d.

CONCLUSIONS

This meta-analysis suggests that green tea consumption is inversely associated with the risk of stroke, especially among those with moderate consumption. Our results support recommendations for green tea consumption to the primary prevention of stroke.

Health Effects of Soy Isoflavones and Green Tea Catechins on Cancer and Cardiovascular Diseases Based on Urinary Biomarker Levels

Plant polyphenols have various health effects. Genistein, which is abundant in soybeans, and epigallocatechin-3-gallate, which is abundant in green tea, are major flavonoids, a subclass group of polyphenols. Several epidemiological studies have shown that these flavonoids have beneficial effects against cancer and cardiovascular diseases. However, other studies did not show such effects. Several confounding factors, including recall bias, are related to these inconsistent findings, and the determination of metabolites in the urine may be useful in reducing the number of confounding factors. Equipment, which can be used by research participants to collect samples from a portion of voided urine within 24 h without the help of medical workers, has been developed for epidemiological investigations. Previous studies, in which flavonoid metabolites in these urine samples were measured, revealed that soy intake was correlated with a reduced risk of certain types of cancer and cardiovascular diseases worldwide. Although soybeans and green tea consumption may have protective effects against cancer and cardiovascular diseases, further clinical studies that consider different confounding factors are required to provide evidence for the actual impact of dietary flavonoids on human diseases, including cancer and cardiovascular diseases. One possible mechanism involved is discussed in relation to the downregulation of reactive oxygen species and the upregulation of 5'-adenosine monophosphate-activated protein kinase elicited by these flavonoids.

Long-term tea consumption reduces the risk of frailty in older Chinese people: Result from a 6-year longitudinal study

Background

Vast accumulative evidence suggests that the consumption of tea and its components have various potential health benefits. This study used a longitudinal study to examine the causality between tea consumption and frailty in older Chinese people.

Methods

This study employed the longitudinal data from 2008 to 2014 of the Chinese Longitudinal Healthy Longevity Survey (CLHLS), which were systematically collected through face-to-face interviews. Two thousand four hundred and seventy three participants completed six-follow-up surveys in 2014 and were analyzed in this study. The frailty index recommended by Searle and co-authors, including 44 health deficits, was used. A Generalized Estimating Equation (GEE) was applied to determine the risk ratio (RR) with a 95% confidence interval (CI) for frailty, and further subgroup analyses were conducted to investigate whether the risk differed stratified by age, sex, and socioeconomic status. Additionally, the interaction between tea consumption with sex and frailty was tested.

Results

Of the 2,473 participants, 14.1% were consistent daily tea drinkers, and 22.6% reported frailty at the 6-year follow-up. Compared to non-tea drinkers, consistent daily tea drinkers reported a significantly lower ratio of having frailty [risk ratio (RR) = 0.54, 95% confidence interval (CI): 0.38-0.78], adjusting for sociodemographic characteristics, health behavior, socioeconomic status, and chronic illnesses. In further subgroup analyses, consistent daily tea consumption significantly reduced the risk of frailty for males (RR = 0.53, 95% CI: 0.32-0.87) but not females (RR = 0.65, 95% CI: 0.37-1.12); in the young (RR = 0.40, 95% CI: 0.22-0.74) but not in the oldest (aged ≥ 80) (RR = 0.66, 95% CI: 0.40-1.06); informal education (RR = 0.48, 95% CI: 0.28-0.84) but not formal education (RR = 0.62, 95% CI: 0.37-1.03); financial dependence (RR = 0.42, 95% CI: 0.25-0.71) but not financial independence (RR = 0.71, 95% CI: 0.41-1.23). Additionally, females showed a lower tea-mediated risk of frailty in occasional tea consumers (RR = 0.51, 95% CI: 0.29-0.89) and inconsistent tea drinkers (RR = 0.58, 95% CI: 0.37-0.93).

Conclusions

Habitual tea consumption can reduce the risk of frailty in older Chinese, and the benefit varied by age, sex, education, and financial support.

Place of Residence and Cognitive Function in Older Adults in China: The Mediating Role of Social Participation

Background: Cognitive impairment is a severe health problem faced by older adults and their families, as well as the countries in which they live. Differences in place of residence may contribute to differences in the cognitive function of older adults, and the mediating effect of social participation has rarely been studied in China. Methods: A total of 10,014 older adult participants were included, using data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Place of residence was described as either a city, town, or rural area. The frequency of participation in organized social activities and visits and interactions with friends was used to assess both formal and informal social participation. The Chinese version of a Mini-Mental State Examination (MMSE) was used as a measure of cognitive function. The mediation analysis was conducted using Hayes' process version 3.4 on SPSS (IBM, Armonk, NY, USA). Results: Place of residence had a negative effect on cognitive function in older adults. The mediating functions of both informal (a1b1 = 0.199) and formal (a2b2 = -0.056) social participation indicate a suppression effect on the part of informal social participation and a partial mediation effect on the part of formal social participation in terms of the association between place of residence and cognitive function in older adults. Promoting both informal and formal social participation seems to be an important strategy for preventing a decline in the cognitive function of older adults, especially for those living in rural areas.

Metabolomics Provides A Novel Interpretation of the Changes in Main Compounds during Black Tea Processing through Different Drying Methods

This study aimed to compare the effect of hot roller (HR) drying and hot air (HA) drying on the sensory evaluation, chemical quality, antioxidant activity, and metabolic profile of Yihong Congou black tea processed from E’cha NO1. The Yihong Congou black tea dried with HA obtained higher sensory scores and better chemical qualities such as the hue of tea brew color (a and b), content of theaflavins, thearubigins, water extract, free amino acids, tea polyphenol, and the ratio of polyphenol to amino acids as well as higher antioxidant capacities compared to that dried with HR. The HA drying tea increased the contents of volatile compounds that had positive correlation with sweet and flowery flavor, while the HR drying tea increased the contents of volatile compounds related to fruity flavor. Moreover, non-targeted metabolomics data indicated that the levels of most free amino acids significantly increased, while the levels of most soluble sugars reduced in the HA drying method compared to the HR drying method. The metabolic analysis was also consistent with the above results and revealed that D-ribose and gallic acid were the main characteristic metabolites of HA drying. Our results could provide a technical reference and theoretical guide to processing a high quality of Yihong Congou black tea.