Independent and Joint Associations of Tea Consumption and Smoking with Parkinson's Disease Risk in Chinese Adults

Neuroprotective effect of green tea extract (-)-epigallocatechin-3-gallate in a preformed fibril-induced mouse model of Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disease characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra (SN). The main bioactive component of green tea polyphenols (-)-epigallocatechin-3-gallate (EGCG) exerts protective effects against diseases such as neurodegenerative diseases and cancer. Therefore, this study investigated the effect of EGCG on the amelioration of neural damage in a chronic PD mouse model induced by α-synuclein preformed fibrils (α-syn-PFFs). A total of 20 C57BL/6J female mice were randomly divided into 3 groups: control group (saline, n = 6), model group (PFFs, n = 7), and prevention group (EGCG+PFFs, n = 7). A chronic PD mouse model was obtained by the administration of α-syn-PFFs by stereotaxic localization in the striatum. Behavioral tests were performed to evaluate PD-related anxiety-like behavior and motor impairments in the long-term PD progression. Tyrosine hydroxylase (TH) immuno-positive neurons and Ser129-phosphorylated α-syn (p-α-syn) were identified by immunohistochemistry. Pro-inflammatory and anti-inflammatory cytokines were measured by real-time quantitative PCR. EGCG pretreatment reduced anxiety-like behavior and motor impairments as revealed by the long-term behavioral test (2 weeks, 1 month, 3 months, and 6 months) on PD mice. EGCG also ameliorated PFF-induced degeneration of TH immuno-positive neurons and accumulation of p-α-syn in the SN and striatum at 6 months. Additionally, EGCG reduced the expression of pro-inflammatory cytokines while promoting the release of anti-inflammatory cytokines. EGCG exerts a neuroprotective effect on long-term progression of the PD model.

The Association between Coffee and Tea Consumption at Midlife and Risk of Dementia Later in Life: The HUNT Study

BACKGROUND

Studies exploring the possible protective effect of coffee and tea consumption on dementia have shown inconsistent results so far. We aimed to investigate whether consumption of tea and different types of coffee at midlife are associated with dementia later in life and whether sex or ApoE4 influence such association.

METHODS

We included 7381 participants from the Norwegian HUNT Study. Self-reported questionnaires assessed daily consumption of coffee and tea at baseline. After 22 years, individuals 70 years or older were screened for cognitive impairment.

RESULTS

General coffee consumption and tea consumption was not associated with dementia risk. Compared to daily consumption of 0-1 cups of coffee, daily consumption of ≥8 cups of boiled coffee was associated with increased dementia risk in women (OR: 1.83, 95% CI: 1.10-3.04, p-value for trend = 0.03) and daily consumption of 4-5 cups of other types of coffee was associated with a decrease in dementia risk in men (OR: 0.48, 95% CI: 0.32-0.72, p-value for trend = 0.05). Furthermore, the association between boiled coffee and increased dementia risk was only found in ApoE4 non-carriers. Differences by sex or ApoE4 carrier status were not supported by strong statistical evidence for interaction. Tea consumption was not associated with dementia risk.

CONCLUSION

type of coffee may play a role in the direction of the association between coffee-drinking habits and dementia later in life.

Age at smoking initiation and smoking cessation influence the incidence of stroke in China: a 10-year follow-up study

Our study aimed to explore the correlation between age at smoking initiation and smoking cessation for the risk for stroke in China. We investigated 50,174 participants from one of the urban areas of China Kadoorie Biobank (CKB) Study. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for association between smoking and incidence of stroke were estimated using Cox regression model. During a median of 10.7 years of follow-up, 4370 total stroke cases were documented. Among men, comparing current smokers to never smokers, the HR of total stroke for current smokers was 1.279 (95% CI, 1.134-1.443) for total stroke. The HRs of total stroke were 1.344 (1.151-1.570) for those started smoking at age less than 20 years, 1.254 (1.090-1.443) for those started smoking at age 20-30 years, and 1.205 (1.012-1.435) for those started smoking at age 30 year and above, with a dose-response relation (P for trend, 0.004). Comparing former smokers to current smokers, in the low pack-year group, those stopped smoking at age less than 65 years had a 18.2% decreased risk for total stroke (0.818; 0.673-0.994). The decreased risk was not found in those stopped smoking at age 65 years and above. Similar results were observed in the high pack-year group. In conclusion, we found that current smokers had a higher stroke risk than never smokers, and the risk increased with a younger age at smoking initiation. Smoking cessation can reduce the risk for stroke, especially could benefit from cessation at a younger age.