Associations between modifiable risk factors and frailty: a Mendelian randomisation study

The causal association between plasma caffeine and frailty: A two-sample mendelian randomization study

BACKGROUND

Frailty is one of the most common and challenging consequences of aging, which negatively affects older adults, their families, and society. Caffeine has been shown to be associated with a reduced risk of frailty by observational studies, yet its causal relationship with frailty remains to be tested using more robust methods.

AIMS

This study aimed to explore the causal association between plasma caffeine and frailty using a two-sample Mendelian Randomization (MR) analysis.

METHODS

Single nucleotide polymorphisms related to plasma caffeine concentrations were selected as instrumental variables. Data on the Frailty Index (FI) were sourced from the UK Biobank and TwinGen meta-analysis (n = 175,226), while data on the Fried Frailty Score (FFS) were obtained from the UK Biobank (n = 386,565). The causal association between plasma caffeine levels and frailty was tested using five MR methods, with the inverse-variance weighted method as the primary approach.

RESULTS

Our results consistently showed significantly negative associations between genetically predicted plasma caffeine with FI (β = -0.050, 95 % CI:0.077 to -0.023, P < 0.001) and FFS (β = -0.049, 95 % CI:0.064 to -0.034, P < 0.001). These results remained robust in further sensitivity analyses using a leave-one-out approach.

CONCLUSION

Our findings confirm a causal relationship between plasma caffeine and frailty and suggest that increasing plasma caffeine levels may help prevent and reduce the risk of frailty.

Mendelian randomization and mediation examination of the immune cell-mediated link between sphingomyelin and stroke

OBJECTIVE

The study established a direct link between stroke and sphingomyelin. The precise biology underlying this connection is yet unknown, though. As a result, we decided to investigate the potential causal relationship between Sphingomyelin and genetic vulnerability to stroke, as well as the potential mediating function that immune cells may play in this process, using Mendelian randomization (MR) approaches.

METHODS

A published genome-wide association study (GWAS) dataset of European populations served as the foundation for the MR Study. The inverse variance weighting (IVW) model is the main technique. Four additional statistical techniques (MR Egger, Weighted median, Simple mode, and Weighted mode) were also employed to enhance the verification process. Reverse MR Analysis was utilized to reinforce the findings, and heterogeneity and horizontal pleipotency were assessed. Additionally, this study looked into potential immune cell mediating roles in the causal link between sphingomyelin and stroke using two-step MR techniques.

RESULT

The IVW metod's results indicated that sphingomyelin genetic susceptibility was linked to a high risk of stroke (OR = 1.045 [95 %CI, 1.004-1.087; P = 0.031). Additionally, the statistical result of SSC-A on CD8br and stroke was IVW [P = 0.007, OR(95 % CI) 1.020 (1.005-1.034)], which was proportionate to the increased risk of stroke. A lower incidence of stroke IVW is linked to CD45 on CD8br [P = 0.004, OR(95 % CI) 0.993 (0.988-0.998)]. Furthermore, our results imply that SSC-A on CD8br and CD45 on CD8br contribute to the causative relationship between sphingomyelin and stroke. The percentages of conciliation are 5.38 %, 22.7 %, 33.5 %), and 0.000999, 0.0152, 0.0132, respectively.

CONCLUSION

We confirmed the effect of sphingomyelin on stroke and conducted in-depth studies. SSC-A on CD8br and CD45 on CD8br is latent stroke mediators associated with sphingomyelin. Through two-step mediated Mendelian randomization analysis, we provide new insights into the etiology and treatment of stroke.

The Application of Voice Biomarkers in Frailty: A Scoping Review

BACKGROUND

With an increasing prevalence of frailty among older adults, effective classification and management strategies for frailty have become imperative. Voice biomarkers, offering insights into the overall health status of older adults, hold promise for enhancing the management of this multifaceted geriatric syndrome.

OBJECTIVES

This scoping review aims to consolidate existing knowledge regarding the relationship between frailty and voice biomarkers.

METHODS

A systematic search was conducted following the preferred reporting items for systematic reviews and meta-analyses extension for scoping reviews guidelines across multiple databases: PubMed, Embase, Proquest, Scopus, and Web of Science. The results were synthesized through information extraction and are presented in tables.

RESULTS

A total of 11 studies met the inclusion criteria. The majority (63.6%) employed a cross-sectional design. Voice biomarkers encompassed acoustic parameters, such as the peak/average volume ratio, and linguistic parameters, such as verbal fluency. Nine articles reported significant associations between frailty and acoustic parameters. Three articles included linguistic parameters in their analyses. Only one demonstrated associations between frailty and both acoustic and linguistic parameters.

CONCLUSION

Despite the relatively small sample sizes in the included studies, the findings underscore a significant connection between voice biomarkers and frailty among older adults, suggesting the potential utility of vocal characteristics as non-invasive indicators for identifying and managing frailty. Integrating voice biomarkers into routine geriatric assessments could substantially improve the precision and efficiency of frailty management, facilitating personalized healthcare interventions tailored to the needs of older adults.

Lead exposure and physical frailty in patients with type 2 diabetes mellitus: cross-sectional results from the METAL study

PURPOSE

Chronic lead exposure continues to be a global environmental concern. Previous studies reported high levels of lead exposure in people with diabetes. Frailty is one of the vital comorbidities of type 2 diabetes mellitus (T2DM); however, researchers have not determined whether lead exposure is a risk factor for frailty in people with T2DM.

METHODS

This cross-sectional study explored the association between blood lead levels and frailty in a Shanghai diabetic population cohort. Individuals who met ≥3 of 5 predefined criteria (weight loss, exhaustion, low physical activity, slow walking speed and low grip strength) were defined as frailty.

RESULTS

A total of 884 participants with T2DM (50.6% men, mean age 70.6 ± 7.4 years) were included. Among them, 147 (16.6%) patients were frail, and the median (interquartile range) concentration of blood lead was 16.0 µg/L (12.0-23.0). Compared with the participants within the lowest quartile of serum lead, positive associations of the 2nd and 4th lead quartiles with frailty were observed (OR, 95% CI; 1.70 1.01-2.84 and 1.72 1.03-2.88, respectively) after adjusting for age, sex and body mass index (BMI). After further adjustment for drinking status, smoking status, diet, education, blood pressure, triglycerides and glycosylated hemoglobin, the associations of serum lead with frailty were still significant for the 4th and 2nd-4th quartiles of lead (1.71, 1.01-2.91 and 1.57, 1.02-2.41, respectively). In the subgroup analyses, we found positive associations of serum lead with frailty in elderly individuals (1.77, 1.13-2.79), those with obesity (2.14, 1.02-4.51), those with unhealthy diets (2.52, 1.26-5.04), and those without hyperlipidemia (2.09, 1.12-3.88), although the interactions were not statistically significant (P for interaction all >0.05).

CONCLUSION

This work provides evidence of an association between chronic lead exposure and physical frailty in a diabetic population in a Chinese cohort. Future prospective and mechanistic studies are warranted to confirm our findings.

The relationship between insomnia and multidimensional frailty in community-dwelling older adults: A systematic review

OBJECTIVE

To examine the relationship between insomnia and multidimensional frailty among community-dwelling older adults.

METHOD

We conducted a comprehensive search in the Pubmed, Web of Science, and Embase databases up to May 15, 2024. The included cross-sectional studies were using the Joanna Briggs Institute's Evidence-Based Health Care Center's checklist for analytical cross-sectional studies; the longitudinal study used the Newcastle-Ottawa Scale for risk of bias assessment.

RESULTS

Out of 1571 studies, 14 were selected. The results indicate a positive relationship between insomnia and cognitive frailty, social frailty, and psychological frailty in community-dwelling older adults. However, the relationship between insomnia and total or physical frailty is unclear.

CONCLUSION

This study made an association between insomnia and cognitive frailty, social frailty, and psychological frailty in community-dwelling older adults. Due to the limited quality and quantity of the included studies, more high-quality cohort studies are required to verify the above conclusion.

The impact of blood pressure lowering agents on the risk of worsening frailty among patients with diabetes mellitus: a cohort study

Patients with diabetes mellitus (DM) are at risk of developing frailty, but studies rarely addressed risk factors for frailty worsening. We investigated whether blood pressure (BP)-lowering agents influenced such risk in these patients. Adults with type 2 DM were identified from National Taiwan University Hospital, with the primary outcome, the worsening of frailty by ≧1 score increase of FRAIL scale determined. We used the Cox proportional hazards analysis to derive the risk of worsening frailty associated with BP-lowering agents. Among 41,440 patients with DM, 27.4% developed worsening frailty after 4.09 years of follow-up. Cox regression revealed that diuretics (hazard ratio (HR) 1.12, 95% confidence interval (CI) 1.06-1.18) and α-blocker (HR 1.14, 95% CI 1.06-1.23) users had a significantly higher risk of worsening frailty than non-users, whereas the risk was lower among β-blocker users (HR 0.93, 95% CI 0.88-0.98). It would be therefore prudent to weigh the advantages and disadvantages of using specific BP-lowering agent classes.

Assessing the causal relationship between frailty and sex hormone-binding globulin or insulin-like growth factor-1 levels: A sex-stratified bidirectional Mendelian Randomization study

BACKGROUND

The association between frailty and sex hormone-binding globulin (SHBG) or insulin-like growth factor-1(IGF-1) levels demonstrates sex differences with inconsistent conclusions. This study aims to explore the causal relationship between frailty and SHBG or IGF-1 levels through bidirectional Mendelian randomization (MR).

METHODS

We conducted two-sample bidirectional sex-stratified MR analyses using summary-level data from genome-wide association studies (GWASs) to examine the causal relationship between frailty and IGF-1 or SHBG levels, as measured by frailty index (FI) and frailty phenotype (FP). We use the random-effects inverse-variance weighted (IVW), weighted median, MR-Egger, MR-Egger intercept, and leave-one-out approaches.

RESULT

The relationship between frailty and SHBG or IGF-1 levels is inversely related, with a significant decrease in SHBG levels in females. Specifically, SHBG levels significantly decrease with FI (β = -5.49; 95 % CI: -9.67 to -1.32; FDR = 0.02) and more pronounced with FP (β = -10.14; 95 % CI: -16.16 to -4.13; FDR = 0.01), as determined by the IVW approach. However, reverse analysis shows no significant effect of IGF-1 or SHBG levels on either FI or FP (p > 0.05).

CONCLUSION

Our study indicates a negative correlation between frailty and the levels of SHBG and IGF-1. It is suggested that further research is required to establish cut-off values for SHBG and IGF-1 levels in the frailty population. This is particularly important for females at higher risk, such as those undergoing menopause, to enable comprehensive assessment and early prevention efforts. While the findings imply that reduced IGF-1 and SHBG levels may not directly contribute to frailty, it is important not to overlook the underlying mechanisms through which they may indirectly influence frailty.

Does tea intake increase the risk of anemia? Evidence from a large prospective cohort and Mendelian randomization study

Tea consumption is avoided by some due to concerns about its potential to cause anemia. To clarify this impact, we assessed the association between tea intake and anemia in a Chinese prospective cohort study and by Mendelian randomization (MR). We analyzed associations of tea intake with anemia using data from the baseline (N = 30 085) and three subsequent follow-ups (the first: N = 17 898; the second: N = 10 435; the third: N = 5311) in the Guangzhou Biobank Cohort Study (GBCS). We also assessed the causal effect of tea intake on anemia, hemoglobin (Hgb) and hematocrit (Hct) using two-sample MR with summary statistics from relevant genome-wide association studies and the UK Biobank (N = 447 485). At the baseline, compared with never-drinkers, regular tea drinkers had higher levels of Hgb and Hct and a lower risk of anemia after adjustment for confounders (all P < 0.05; all P for trend ≤0.006). Prospectively, compared with never-drinkers, regular tea drinkers had higher Hgb (g L-1) (β = 0.69; 95% CI, 0.28 to 1.10; P for trend <0.001) and Hct (%) (β = 0.30; 95% CI, 0.19 to 0.41; P for trend <0.001), but no significant difference in anemia risk (OR = 0.91; 95% CI, 0.82 to 1.02; P for trend = 0.071). MR analyses showed no association between tea intake and anemia, Hgb and Hct. Through triangulation of evidence using a Chinese cohort and genetics, tea consumption appears unlikely to impact anemia risk.

Association between pre-stroke frailty status and stroke risk and impact on outcomes: a systematic review and meta-analysis of 1,660,328 participants

The prevalence of frailty is increasing, and it is associated with increased risk of diseases and adverse outcomes. Although substantial research has focused on post-stroke frailty, understanding of pre-stroke frailty remains limited. Our aim was to synthesize literature on pre-stroke frailty and stroke risk to explore their relationship and impact on prognosis. A systematic search of multiple databases was conducted to identify cohort studies published until October 28, 2023. Meta-analysis was conducted using a random effects model. Heterogeneity was assessed with the I² statistic, and publication bias was evaluated using Begg's test. Finally, we included 11 studies (n = 1,660,328 participants). The pooled hazard ratios (HRs) for stroke risk associated with pre-stroke frailty compared to non-frail individuals was 1.72 (95% confidence interval, CI: 1.46-2.02, p = 0.002, I2 = 69.2%, Begg's test: p = 0.536). The pooled HRs for mortality and the pooled relative risk (RRs) modified Rankin Scale (mRs) associated with pre-stroke frailty were 1.68 (95% CI: 1.10-2.56, p = 0.136, I2 = 49.9%, Begg's test: p = 0.296) and 3.11 (95% CI: 1.77-5.46, p = 0.192, I2 = 39.4%, Begg's test: p = 1.000), respectively. In conclusion, pre-stroke frailty is strongly associated with stroke risk and impacts its prognosis, irrespective of the measurement method. Future research should focus on prospective studies to assess the effects of early intervention for frailty. This has significant implications for primary healthcare services and frailty management.

Associations between modifiable risk factors and frailty progression among individuals with pre-frailty

BACKGROUND

In the context of the present global aging phenomenon, the senior population and pace of aging in China have emerged as prominent issues on the worldwide stage. Frailty, a complicated condition that is closely linked to the clinical syndrome of advancing age, poses a considerable health risk to older individuals. Frailty status was assessed by the frailty index (FI) ranging from 0 to 1, pre-frailty was defined as >0.10 to <0.25, and frailty was defined as ≥0.25. To look at the connection between modifiable risk factors and frailty progression among individuals in the pre-frailty population.

METHODS

Using pre-frailty patients as characterized by the 32-frailty index, the study focused on middle-aged and elderly persons from China and ultimately recruited 5,411 participants for analysis. The relationship between modifiable factors and changes in pre-frailty status throughout follow-up was investigated. Modifiable factors were body mass index (BMI), abdominal obesity, smoking status, alcohol use, and sleep status. We employed logistic regression to examine the relationships between modifiable risk factors and changes in pre-frailty status, as well as the associations between modifiable factors scores and the corresponding pre-frailty progression. Additionally, we generated the modifiable factors scores and examined how these related to modifications in the pre-frailty stage.

RESULTS

In this study, after a mean follow-up of 6 years, (OR = 0.59, 95%CI: 0.48-0.71) for BMI ≥ 25 kg/m2 and (OR = 0.74, 95%CI: 0.63-0.89) for concomitant abdominal obesity were significantly associated with lower reversal to a healthy state; (OR = 1.24, 95%CI:1.07-1.44) and (OR = 1.25, 95%CI: 1.10-1.42) for the group that negatively progressed further to frailty were significantly associated with increased frailty progression profile. Subsequently, investigation of modifiable factor scores and changes of pre-frailty status found that as scores increased further, frailty developed (OR = 1.12, 95%CI:1.05-1.18), with scores of 3 and 4 of (OR = 1.38, 95%CI: 1.08-1.77) and (OR = 1.52, 95%CI:1.09-2.14). Finally, we also performed a series of stratified analyses and found that rural unmarried men aged 45 to 60 years with less than a high school degree were more likely to develop a frailty state once they developed abdominal obesity.

CONCLUSION

In pre-frailty individuals, maintaining more favorable controllable variables considerably enhances the chance of return to normal and, conversely, increase the risk of progressing to the frailty.

Causal relationship between neuroticism and frailty: A bidirectional Mendelian randomization study

BACKGROUND

Observational studies have shown that neuroticism is associated with frailty, but the causal relationship between them remains unclear.

METHODS

A two-sample Mendelian randomization (MR) study was conducted to explore the bidirectional causal relationship between neuroticism (n = 380,506 for the primary analysis, n = 79,004 for the validation) and frailty (n = 175,226) using publicly available genome-wide association study data. The inverse variance weighted (IVW), weighted median, and MR-Egger were used to obtain the causal estimates. Findings were verified through extensive sensitivity analyses and validated using another dataset. Multivariable MR (MVMR) analysis was performed to estimate the direct causal effects with adjustment of potential confounders. Two-step MR technique was then conducted to explore the mediators in the causal effects of neuroticism on frailty.

RESULTS

Genetically-predicted higher neuroticism score was significantly correlated with higher frailty index (IVW beta: 0.53, 95%CI: 0.48 to 0.59, P = 9.3E-83), and genetically-determined higher frailty index was significantly associated with higher neuroticism score (IVW beta: 0.28, 95%CI: 0.21 to 0.35, P = 1.3E-16). These results remained robust across sensitivity analyses and were reproducible using another dataset. The MVMR analysis indicated that the causal relationships remained significant after adjusting for the potential confounding factors. Mediation analysis revealed that depression, years of schooling, and smoking were significantly mediated the causal effects of neuroticism on frailty.

CONCLUSIONS

A bidirectional causal relationship existed between neuroticism and frailty. Our findings suggested that early intervention and behavioral changes might be helpful to reduce the neuroticism levels and prevent the development of frailty.

Causal effects of socioeconomic traits on frailty: a Mendelian randomization study

Background

The relationship between socioeconomic status and frailty has been extensively investigated in the literature, but it remains unclear whether a causal relationship exists. Our goal is to evaluate the causal relationship between six socioeconomic traits and the frailty index using summary-level data for single nucleotide polymorphisms from large genome-wide association studies with individuals of European ancestry.

Methods

A two-sample MR was performed. We applied the inverse variance weighted (IVW) method for the primary estimate, with sensitivity analyses conducted using alternative MR methods to evaluate the robustness of the findings. A subsequent multivariable MR was undertaken to adjust for the effects of body mass index (BMI). Finally, the MR Steiger directionality test was performed to confirm the causal direction.

Results

The IVW MR analysis revealed significant associations between various socioeconomic factors and the frailty index. Specifically, genetically predicated age completed full time education (β = -0.477, 95% confidence interval [CI]: -0.634 to -0.319) and average total household income before tax (β = -0.321, 95% CI: -0.410 to -0.232) were negatively associated with the frailty index. On the other hand, genetically predicted job involves heavy manual or physical work (β = 0.298, 95% CI: 0.113 to 0.484), job involves mainly walking or standing (β = 0.179, 95% CI: 0.013 to 0.345), Townsend deprivation index at recruitment (β = 0.535, 95% CI: 0.285 to 0.785), and social isolation/loneliness (β = 1.344, 95% CI: 0.834 to 1.853) were positively associated with the frailty index. Sensitivity analysis using other MR methods and multivariable MR analysis adjusting for BMI yielded stable results. The MR Steiger directionality test confirmed the causal direction.

Conclusion

Our findings highlight the importance of socioeconomic factors in affecting frailty risk. Future research should focus on unraveling the pathways through which these socioeconomic factors exert their effects on frailty, with the ultimate goal of developing targeted strategies to mitigate the risk of frailty.

Association of cooking oil and incident of frailty in older adults: a cohort study

BACKGROUND

Studies examining the potential association between cooking oil and frailty risk in older adults have produced conflicting outcomes. Therefore, our objective was to explore the relationship between cooking oil (vegetable and animal fat oils), changes in oil usage, and the risk of frailty in older adults.

METHODS

We included 4,838 participants aged ≥ 65 years without frailty (frailty index < 0.25) from the 2011 wave of the Chinese Longitudinal Healthy Longevity Survey. Follow-up occurred in the 2014 and 2018 waves. Cox proportional hazard models were utilized to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) to examine the association between cooking oil and frailty. Additionally, we evaluated the effect of switching cooking oil on frailty during the follow-up period.

RESULTS

During a median follow-up of 3.0 (2.8-6.9) years, 1,348 individuals (27.9%) developed frailty. Compared to those using vegetable oil, users of animal fat oil had a lower risk of frailty (HR = 0.72, 95% CI: 0.61-0.85). Participants who switched from vegetable oil to animal fat oil, as well as those consistently using animal fat oil, had lower risks of frailty with HRs of 0.70 (0.52-0.95) and 0.63 (0.51-0.77) respectively, compared to those who consistently used vegetable oil. Conversely, individuals who switched from animal fat oil to vegetable oil experienced an increased risk of frailty (HR: 1.41, 95% CI: 1.01-1.97).

CONCLUSIONS

The utilization of animal fat oil in cooking exhibited a reduced frailty risk among older adults. Conversely, transitioning from animal fat oil to vegetable oil may elevate the risk. These findings propose that substituting vegetable oil with animal fat oil in the diet may safeguard against frailty.

Causal effects of blood pressure and the risk of frailty: a bi-directional two-sample Mendelian randomization study

Observational studies have indicated that high blood pressure (BP) may be a risk factor to frailty. However, the causal association between BP and frailty remains not well determined. The purpose of this bi-directional two-sample Mendelian randomization (MR) study was to investigate the causal relationship between BP and frailty. Independent single nucleotide polymorphisms (SNPs) strongly (P < 5E-08) associated with systolic BP (SBP), diastolic BP (DBP), and pulse pressure (PP) were selected as instrumental variables. Two different published genome-wide association studies (GWAS) on BP from the CHARGE (n = 810,865) and ICBP (n = 757,601) consortia were included. Summary-level data on frailty index (FI) were obtained from the latest GWAS based on UK Biobank and Swedish TwinGene cohorts (n = 175,226). Inverse variance weighted (IVW) approach with other sensitivity analyses were used to calculate the causal estimate. Using the CHARGE dataset, genetic predisposition to increased SBP (β = 0.135, 95% CI = 0.093 to 0.176, P = 1.73E-10), DBP (β = 0.145, 95% CI = 0.104 to 0.186, P = 3.14E-12), and PP (β = 0.114, 95% CI = 0.070 to 0.157, p = 2.87E-07) contributed to a higher FI, which was validated in the ICBP dataset. There was no significant causal effect of FI on SBP, DBP, and PP. Similar results were obtained from different MR methods, indicating good stability. There was potential heterogeneity detected by Cochran's Q test, but no horizontal pleiotropy was observed in MR-Egger intercept test (P > 0.05). These findings evinced that higher BP and PP were causally associated with an increased risk of frailty, suggesting that controlling hypertension could reduce the risk of frailty.