Association of CRP gene polymorphisms with CRP levels, frailty and co-morbidity in an elderly Chinese population: results from RuLAS

Prevalence and patterns of multimorbidity in China during 2002-2022: A systematic review and meta-analysis

BACKGROUND

Multimorbidity is common, particularly among elderly people. Restructuring health service systems to better manage this public health issue requires knowledge regarding disease prevalence and patterns. We quantified the epidemiology characteristics of multimorbidity among adults in China to inform policy-making and resource allocation.

METHODS

We searched 10 databases for studies (January 2000-October 2023) reporting primary epidemiological multimorbidity data for adults in China. We included observational studies; we excluded duplicate publications and studies investigating a single comorbidity pattern, focused on specific population categories, using medical insurance reimbursement data, and with unclear/incomplete data. We assessed risk of bias using the STROBE checklist and estimated heterogeneity among studies. The prevalence was pooled using the random-effects method and sample size as weight.

FINDINGS

Of 13,998 records retrieved, 67 studies (30 in English, 37 in Chinese) were included. The prevalence (95% confidence interval) of multimorbidity was 25.4% (15.1%, 35.7%) among Chinese adults. Among 42 studies reporting age-specific prevalence, multimorbidity prevalence increased rapidly with age: 3.3% (0%, 15.2%) for age 18-29 years, 5.9% (0%, 12.9%) for 30-44 years, 17.6% (6.1%, 29.1%) for 45-59 years, 32.4% (16.1%, 48.7%) for 60-69 years, 38.5% (23.6%, 53.4%) for 70-79 years, and 40.2% (20.8%, 59.6%) for age ≥ 80 years. Overall prevalence of multimorbidity has increased in recent years, with regional disparity. The most common patterns included hypertension with hearing impairment (10.4% [95% CI: 4.3%, 16.5%]), dyslipidemia (8.9% [4.1%, 13.6%]), and diabetes (8.7% [3.7%, 13.8%]).

CONCLUSION

Multimorbidity was present nearly one in four Chinese adults, with hypertensive diseases and other comorbidities being the most-observed pattern; the prevalence increased rapidly with increased age. There is huge variation in the prevalence of multimorbidity across China. Coordinated, comprehensive strategies are urgently needed to control the ongoing impact of multimorbidity.

Genetically downregulated Interleukin-6 signalling is associated with a lower risk of frailty

BACKGROUND

numerous studies point towards a critical role of Interleukin 6 (IL-6) pathway in frailty pathogenesis yet the causal relationship between the two remains elusive.

METHODS

we selected genetic variants near the IL-6 receptor locus (IL-6R) associated with reduced C-reactive protein (CRP) levels, a downstream effector of IL-6 pathway, and we used them as genetic proxies of IL-6 signalling downregulation. We then performed a two-sample Mendelian randomisation (MR) to investigate the association with frailty status, as defined by the Frailty Index (FI) in 11,171 individuals from the Hellenic Longitudinal Investigation of Ageing and Diet (HELIAD) study. MR analysis was repeated after excluding depression or cognition-related FI items as well as following age or sex stratification. Association with frailty was also examined using an alternative instrument, weighted on s-IL-6R levels. Replication was attempted in UK Biobank dataset.

RESULTS

genetic predisposition to IL-6 signalling downregulation, weighted on CRP levels, was associated with lower risk of frailty, inserted either as categorical (odds ratio [95% confidence interval] = 0.15 [-3.39, -0.40], P = 0.013) or continuous variable (beta [se] = -0.09 [0.003], P = 0.0009). Sensitivity analyses revealed similar estimates across different MR methods with no evidence for horizontal pleiotropy or heterogeneity. Results remained robust after exclusion of depression or cognition-related FI items and following sex or age stratification. Genetically increased s-IL-6R levels were negatively correlated with frailty and this finding remained significant in a meta-analysis of UK Biobank and HELIAD cohorts.

CONCLUSION

our results support a potential causal effect of IL-6 signalling on frailty and further suggest that downregulation of IL-6 levels may reduce frailty risk.

Pre-diagnostic C-reactive protein concentrations, CRP genetic variation and mortality among individuals with colorectal cancer in Western European populations

BACKGROUND

The role of elevated pre-diagnostic C-reactive protein (CRP) concentrations on mortality in individuals with colorectal cancer (CRC) remains unclear.

METHODS

We investigated the association between pre-diagnostic high-sensitivity CRP concentrations and CRP genetic variation associated with circulating CRP and CRC-specific and all-cause mortality based on data from 1,235 individuals with CRC within the European Prospective Investigation into Cancer and Nutrition cohort using multivariable-adjusted Cox proportional hazards regression.

RESULTS

During a median follow-up of 9.3 years, 455 CRC-specific deaths were recorded, out of 590 deaths from all causes. Pre-diagnostic CRP concentrations were not associated with CRC-specific (hazard ratio, HR highest versus lowest quintile 0.92, 95% confidence interval, CI 0.66, 1.28) or all-cause mortality (HR 0.91, 95% CI 0.68, 1.21). Genetic predisposition to higher CRP (weighted score based on alleles of four CRP SNPs associated with higher circulating CRP) was not significantly associated with CRC-specific mortality (HR per CRP-score unit 0.95, 95% CI 0.86, 1.05) or all-cause mortality (HR 0.98, 95% CI 0.90, 1.07). Among four investigated CRP genetic variants, only SNP rs1205 was significantly associated with CRC-specific (comparing the CT and CC genotypes with TT genotype, HR 0.54, 95% CI 0.35, 0.83 and HR 0.58, 95% CI 0.38, 0.88, respectively) and all-cause mortality (HR 0.58, 95% CI 0.40, 0.85 and 0.64, 95% CI 0.44, 0.92, respectively).

CONCLUSIONS

The results of this prospective cohort study do not support a role of pre-diagnostic CRP concentrations on mortality in individuals with CRC. The observed associations with rs1205 deserve further scientific attention.

PTPN22 gene functional polymorphism (rs2476601) in older adults with frailty syndrome

The frailty syndrome is a common clinical marker of vulnerability in older adults conducive to an overall decline in inflammatory stress responsiveness; yet little is known about the genetic risk factors for frailty in elderly. Our aim was to investigate the association between the rs2476601 polymorphism in PTPN22 gene and susceptibility to frailty in Mexican older adults. Data included 630 subjects 70 and older from The Coyoacán cohort, classified as frail, pre-frail, and non-frail following Fried's criteria. Sociodemographic and clinical characteristics were compared between groups at baseline and after a multivariate analysis. The rs2476601 polymorphism was genotyped by TaqMan genotyping assay using real-time PCR and genotype frequencies were determined for each frailty phenotype in all participants and subsets by age range. Genetic association was examined using stratified and interaction analyses adjusting for age, sex and variables selected in the multivariate analysis. Disability for day-life activities, depression and cognitive impairment were associated with the risk of pre-frailty and frailty at baseline and after adjustment. Carrying the T allele increased significantly the risk of frailty in patients 76 and older (OR 5.64, 95% CI 4.112-7.165) and decreased the risk of pre-frailty under no clinical signs of depression (OR 0.53; 95% CI 0.17-1.71). The PTPN22 polymorphism, rs2476601, could be a genetic risk factor for frailty as subject to quality of life. This is the first study analyzing such relationship in Mexican older adults. Confirming these findings requires additional association studies on wider age ranges in populations of older adults with frailty syndrome.

Association of CRP genetic variation with symptomatology, cognitive function, and circulating proinflammatory markers in civilian women with PTSD

BACKGROUND

Posttraumatic stress disorder (PTSD) has been associated with increased inflammation. C-reactive protein (CRP) is a marker of systemic inflammation, and recently, single nucleotide polymorphisms (SNPs) in the CRP gene have been associated with increased blood CRP protein levels and illness severity in PTSD patients. However, the mechanism by which the CRP SNPs are involved in PTSD remains unclear. Here we investigated the association of CRP genetic variation with blood proinflammatory protein levels, symptomatology, and cognitive function, and further explored the moderating effect of childhood maltreatment history, in adult patients with PTSD.

METHODS

Fifty-seven Japanese civilian women with PTSD and 73 healthy control women were enrolled. Three SNPs in the CRP gene, namely rs2794520, rs1130864, and rs3093059, were genotyped, and analyses focused on rs2794520 (T/C). Serum levels of high-sensitivity CRP (hsCRP), high-sensitivity tumor necrosis factor-α (hsTNF-α), and interleukin-6 were measured. PTSD symptoms were evaluated by the Posttraumatic Diagnostic Scale. Cognitive function was assessed by the Repeatable Battery for the Assessment of Neuropsychological Status. Childhood maltreatment history was assessed by the Childhood Trauma Questionnaire.

RESULTS

Patients with the rs2794520 CC/CT genotype, compared to those with the TT genotype, showed significantly higher levels of hsCRP (p=0.009) and hsTNF-α (p=0.001), more severe PTSD symptoms (p=0.036), and poorer cognitive function (p=0.018). A two-way analysis of variance revealed a significant genotype-by-maltreatment interaction for more severe PTSD avoidance symptom (p=0.012).

LIMITATIONS

The relatively small sample size limited our findings.

CONCLUSIONS

These findings may provide an insight into the etiology of PTSD from the inflammatory perspective.

Genetics of frailty: A longevity perspective

Frailty is a complex late life phenotype characterized by cumulative declines in multiple physiological systems that increases the risk for disability and mortality. The biological changes associated with aging are risk factors for frailty as well as for complex diseases; whereas longevity is assumed to be an outcome of protective biological mechanisms. Understanding the interplay between biological alterations associated with aging and protective mechanisms associated with longevity in the context of frailty may help guide development of interventions to increase healthspan and promote successful aging. The complexity of these phenotypes and relatively low heritability in studies are the main roadblocks in deciphering genetic mechanisms of these age associated conditions. We review genetic research related to frailty, and discuss the possible intertwined biology of frailty and longevity.

C-reactive protein gene rs1205 polymorphism is associated with low-grade chronic inflammation in postmenopausal women

Background

Cardiovascular disease is the leading cause of death in postmenopausal women, and inflammation is a key mechanism involved in the pathogenesis of atherosclerosis. High-sensitivity C-reactive protein (hs-CRP) has been used as a biomarker of inflammation. Considering that CRP gene rs1205 polymorphism has been associated with hs-CRP circulating levels, we evaluated whether rs1205 genotypes influence the presence of low-grade chronic inflammation, acting as a marker of cardiovascular risk.

Methods

We performed a cross-sectional study with biobanked blood samples from 327 postmenopausal women with no evidence of clinical disease. Genotyping for rs1205 C > T SNP of the CRP gene was done by real-time polymerase chain reaction with allelic discrimination assays.

Results

Mean age was 55.6 ± 5.6 years. Mean body mass index (BMI) was 27.3 ± 4.7. Participants were divided according to hs-CRP levels: ≥3 mg/l (low-grade chronic inflammation) or < 3 mg/l. The frequency of allele C at rs1205 was 74.2% in the hs-CRP ≥ 3 mg/l group vs. 59% in the hs-CRP < 3 mg/l. In a multivariable model, higher prevalence of hs-CRP ≥ 3 mg/l was associated with CC genotype (PR 1.53; 95%CI 1.07-2.18; p = 0.018) and waist circumference ≥ 88 cm (PR 2.45; 95%CI 1.66-3.60; p < 0.001).

Conclusions

CRP rs1205 CC homozygotes may be at higher risk of a low-grade chronic inflammatory status compared to individuals carrying the T allele.

Gender-Specific Differences in Concentrations of Biochemical Parameters in Persons over the Age of 90

The ageing process is a phenomenon leading to an emergence of a web of interrelated biological processes producing significant changes in the human body. The aim of the paper was to analyse gender-specific differences with regard to selected biochemical parameters in longevity. The study was conducted in Poland in 2017. The study population comprised of long-lived individuals, both living at home and staying at residential care homes. There were 90 people of both genders (69 women and 21 men) aged between 90 and 103 years (mean = 92.36; SD = 2.98). The biochemical markers of longevity in the studied patients were identified by assessing their pro-inflammatory and anti-inflammatory status in various metabolic aspects. The analysis of biochemical variables revealed numerous statistically significant differences, both in the study group as a whole and between the genders. The ageing process is extremely complex, but understanding it will allow for a real intervention in life extension. Research into the processes involved in ageing and longevity will enable a better understanding of the mechanisms responsible for them, and to enjoy those processes in good health.

Immunogenicity of the Varicella-Zoster Vaccine in Community-Dwelling Non-robust Elderly Individuals Compared to Robust Elderly Individuals: A Prospective Cohort Study

To determine whether immunogenicity of the herpes zoster live-attenuated vaccine (ZVL) in elderly individuals is influenced by frailty status and cytokine levels, individuals aged at least 65 years were prospectively administered ZVL after their frailty status and cytokine levels were assessed. Humoral and cellular immunogenicity were assessed using enzyme-linked immunosorbent assays for the varicella-zoster virus–specific IgG antibody and varicella-zoster virus–specific enzyme-linked immunospot assays, before and 6 weeks after vaccination. We enrolled 69 participants (mean age, 74.3 years); 31 were non-robust. Thirty-seven participants had a greater than 2 geometric mean fold rise in IgG antibodies, 22 more participants had at least 10 spot-forming cells/106 peripheral blood mononuclear cells (from 35 to 57 participants), and 42 experienced a twofold geometric mean fold rise increase of spot-forming cells 6 weeks after vaccination. The geometric mean fold rises of the antibody titers were similar in the robust and non-robust groups; moreover, the baseline enzyme-linked immunospot assay geometric mean values were not significantly different before or 6 weeks after vaccination. We observed no significant correlations between baseline cytokine levels and immunogenicity. Approximately half of the community-dwelling elderly participants in this study experienced a twofold rise in antibodies and one-third more participants showed at least 10 spot-forming cells after ZVL administration, suggesting that the ZVL can boost immunity in non-robust (especially pre-frail) and robust elderly individuals.

CRP-level-associated polymorphism rs1205 within the CRP gene is associated with 2-hour glucose level: The SAPPHIRe study

C-reactive protein (CRP) encoded by CRP gene is a reflection of systemic inflammation. Many studies associated CRP level with diabetes and glucose levels, but the association of CRP gene with these traits is unclear. We conducted a cross-sectional study consisting of 945 siblings from 330 families collected by the Stanford Asian Pacific Program in Hypertension and Insulin Resistance (SAPPHIRe) to investigate associations between CRP polymorphisms, circulating CRP, diabetes, and glucose levels. Five single-nucleotide polymorphisms were analyzed: rs3093059, rs2794521, rs1417938, rs1800947, and rs1205. The generalized estimating equation approach was used to deal with correlated data within families. CRP level was positively correlated with diabetes prevalence and levels of fasting and 2-hour glucose (each P < 0.008). Alleles C at rs3093059 and G at rs1205 were associated with elevated CRP level (each P < 1.2 × 10⁻⁶). Allele C at rs3093059 was associated with fasting glucose (β = 0.20, P = 0.045) and G at rs1205 was associated with 2-hour glucose (β = 0.46, P = 0.00090) post oral glucose tolerance test, but only the latter passed Bonferroni correction. No polymorphism was associated with diabetes. Since 2-hour glucose is an indicator of glucose tolerance, this study indicated CRP gene is associated with glucose intolerance.

C-Reactive Protein and Frailty in the Elderly: A Literature Review

Chronic inflammation is a well-established background process in many age-related diseases. Many recent studies investigate the use of various inflammatory biomarkers such as C-reactive protein (CRP), interleukin-6, and interleukin-1 as predictors of physical and cognitive performance among elders. The phenotype of frailty has also been associated with underlying inflammatory mechanisms. The aim of this article was to review the literature referring to the correlation of CRP serum levels and frailty in older individuals. We tried to identify all relevant publications regarding the relation of CRP as an index of frailty in the elderly and its potential use. Although many studies in the recent medical literature positively associate serum CRP levels and frailty in older individuals, some do not, and some raise some interesting questions and set the basis for future studies. The association of CRP and frailty in elder patients should be considered when clinicians interpret inflammatory biomarkers in various clinical settings in such patients. Well-designed, prospective clinical trials are warranted to better assess the role and pathophysiology of frailty in the elderly and its mechanisms as also the exact role of CRP as an inflammatory marker and as a prognostic index in this syndrome.