The frailty phenotype (FP) proposed by Fried and colleagues (Fried LP, Tangen CM, Walston J, et al.; Cardiovascular Health Study Collaborative Research Group. Frailty in older adults: evidence for a phenotype. J Gerontol A Biol Sci Med Sci. 2001;56:M146–M156.) requires the administration of performance tests (gait speed, handgrip strength) not always feasible in routine clinical practice. Furthermore, the discriminative capacity of the instrument has been rarely investigated. Aim of this study was to evaluate the discriminative capacity of the FP and compare it with a modified version including only anamnestic information.
Data are from 890 participants of the InCHIANTI study without impairment in activities of daily living (ADL) at baseline (mean age 74 years, women 55%). Frailty was defined by (a) the presence of ≥3 criteria of the FP, and (b) having ≥2 criteria of an anamnestic FP (AFP), not including gait speed and handgrip strength. Sensitivity, specificity, positive and negative predictive values (PPV, NPV) were used to evaluate the discriminative capacity of both definitions for incident disability (ie, loss of at least one ADL), incidence of “accelerated” disability (loss of >2 ADL) over a 6-year follow-up, and 5-years mortality.
FP and AFP yielded a frailty prevalence of 6.4% and 6.5%, respectively; only 32 patients were considered frail by both indices (kappa: .53). For incident disability, FP showed sensitivity = .194, specificity = .963, PPV = .400, and NPV = .903. Similarly, AFP had sensitivity = .129, specificity = .949, PPV = .245, and NPV = .894. Consistent results were found for accelerated disability and mortality.
In our sample, both FP and AFP showed low sensitivity in identifying older people who would die or develop disability, but they could well discriminate people who would not experience adverse outcomes.
Frailty; Disability; Mortality; Predictive value; Sensitivity and specificity.
Recent studies indicate a role for the age-related decline of anabolic hormones, especially testosterone, in the onset of “anemia of aging.” Some of testosterone’s erythropoietic activities are mediated by insulin-like growth factor (IGF)-1, which also seems to have independent erythropoietic effects. However, the associations among IGF-1, anemia, and hemoglobin (Hb) have not been adequately investigated in older populations.
We used data from a representative sample of 953 subjects ≥65 years who participated in the InCHIANTI (Invecchiare in Chianti) Study and were not on growth hormone (GH) or erythropoietin therapy and were not diagnosed with hematologic malignancies or other cancers. Anemia was defined according to the World Health Organization (WHO) criteria by Hb level ≤13 g/dL in males and ≤12 g/dL in females. Backward multiple regression analyses including age, IGF binding protein (IGFBP)-3, testosterone, comorbidities, inflammatory markers, and anemia-related measures were used to address the relationship between IGF-1 and Hb and between IGF-1 and anemia in both sexes.
We found that 46/410 (11.2%) males and 71/543 (13.0%) females were defined as anemic. After adjustment for age, anemic males (100 ± 54 vs. 130 ± 56, P<.001) and females (89.1 ± 48 vs. 110 ± 52, P = .001) exhibited lower IGF-1 levels than their nonanemic counterparts. IGF-1 levels were independently and negatively associated with anemia in males (β ± SE = –0.0005 ± 0.0002, P = .04) but not in females (β ± SE = –0.0002 ± 0.0002, P = .40). In both males (β ± SE = 0.002 ± 0.001, P = .03) and females (β ± SE = 0.002 ± 0.0009, P = .03), IGF-1 levels were independently and positively associated with Hb levels.
In older males but not in females, IGF-1 levels are negatively associated with anemia. IGF-1 levels are independent and positive determinants of Hb concentration in both sexes.
Chronic low-grade inflammation reflects a subclinical immune response implicated in the pathogenesis of complex diseases. Identifying genetic loci where DNA methylation is associated with chronic low-grade inflammation may reveal novel pathways or therapeutic targets for inflammation.
We performed a meta-analysis of epigenome-wide association studies (EWAS) of serum C-reactive protein (CRP), which is a sensitive marker of low-grade inflammation, in a large European population (n = 8863) and trans-ethnic replication in African Americans (n = 4111). We found differential methylation at 218 CpG sites to be associated with CRP (P < 1.15 × 10–7) in the discovery panel of European ancestry and replicated (P < 2.29 × 10–4) 58 CpG sites (45 unique loci) among African Americans. To further characterize the molecular and clinical relevance of the findings, we examined the association with gene expression, genetic sequence variants, and clinical outcomes. DNA methylation at nine (16%) CpG sites was associated with whole blood gene expression in cis (P < 8.47 × 10–5), ten (17%) CpG sites were associated with a nearby genetic variant (P < 2.50 × 10–3), and 51 (88%) were also associated with at least one related cardiometabolic entity (P < 9.58 × 10–5). An additive weighted score of replicated CpG sites accounted for up to 6% inter-individual variation (R2) of age-adjusted and sex-adjusted CRP, independent of known CRP-related genetic variants.
We have completed an EWAS of chronic low-grade inflammation and identified many novel genetic loci underlying inflammation that may serve as targets for the development of novel therapeutic interventions for inflammation.
Electronic supplementary material
The online version of this article (doi:10.1186/s13059-016-1119-5) contains supplementary material, which is available to authorized users.
Inflammation; DNA methylation; Epigenome-wide association study; C-reactive protein; Body mass index; Diabetes; Coronary heart disease
Background and aims
There is evidence that distinct genetic polymorphisms of LRP5 are associated with low Bone Mineral Density (BMD) and the risk of fracture. However, relationships between LRP5 polymorphisms and micro- and macro-architectural bone characteristics assessed by pQCT have not been studied. The aim of the present study was to investigate the association of Ala1330Val and Val667Met polymorphisms in LRP5 gene with volumetric BMD (vBMD) and macro-architectural bone parameters in a population-based sample of men and women.
We studied 959 participants of the InCHIANTI study (451 men and 508 women, age range: 21–94 yrs). Trabecular vBMD (vBMDt, mg/cm3), cortical vBMD (vBMDc, mg/cm3), cortical bone area (CBA, mm2) and cortical thickness (Ct.Th, mm) at the level of the tibia were assessed by peripheral quantitative computed tomography (pQCT). Ala1330Val and Val667Met genotypes were determined on genomic DNA by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).
In age-adjusted analyses both LRP 1330-valine and LRP 667-metionin variants were associated with lower vBMDt in men (p<0.05), and lower vBMDt (p<0.05), Ct.Th (p<0.05) and CBA (p<0.05) in women. After adjusting for multiple confounders, only the association of LRP5 1330-valine and 667-metionin with CBA remained statistically significant (p=0.04 and p=0.01, respectively) in women.
These findings suggest that both Ala1330Val and Val667Met LRP5 polymorphisms may affect the determination of geometric bone parameters in women.
Cortical bone area; LRP5 gene polymorphism; osteoporosis; peripheral bone quantitative computed tomography (pQCT); volumetric BMD
Ghrelin is a stomach secreted hormone, believed to play an important role in energy balance and in food intake. Experimental studies have shown a positive effect of ghrelin on bone metabolism, but both in vivo and clinical findings have been contradictory. We aimed to investigate the effect of ghrelin on volumetric BMD in a large cohort of elderly subjects.
We have studied 401 women (mean age 75.1 years, range 65–94) and 306 men (mean age 73.9 years, range 65–94) from the InChianti study, which included measurements of BMD using quantitative CT of the tibia and of body composition using bio impedancemetry. Serum ghrelin was measured using ELISA. We excluded participants with diabetes, hyperthyroidism, using hormone replacement or glucocorticoid therapy. We evaluated the correlation of ghrelin with total, trabecular, and cortical BMD using Pearson's coefficient, and linear regression models to estimate the association between ghrelin and BMD controlling for potential confounders.
In women, after correction for potential confounders, ghrelin was associated with trabecular BMD (β = 7.08, P<0.02), but not with total or cortical BMD. In men, adjusted multivariable models showed a nearly significant association between serum ghrelin and trabecular BMD (β = 4.99, P = 0.069) and no association with either cortical or total BMD.
Serum ghrelin is positively correlated with trabecular BMD in a cohort of elderly healthy Italian women. The fact that trabecular is more metabolically active than cortical bone and the larger number of females might explain this selective association.
Ghrelin; Bone mass; pQCT; Aged; 65 years and older; Cross-sectional studies
Polyphenols have beneficial effects on several chronic diseases but assessing polyphenols intake from self-reported dietary questionnaires tends to be inaccurate and not very reliable. A promising alternative is to use urinary excretion of polyphenols as a proxy measure of intake. The best method to assess urinary excretion is to collect 24-h urine. However, since collecting 24-h urine method is expensive, time consuming and may be difficult to implement in large population-based studies, measures obtained from spot urine normalized by creatinine are commonly used. The purpose of the study was to evaluate the correlation between polyphenols dietary intake and total urinary polyphenol excretion (TPE), expressed by both 24-h volume and urinary creatinine normalization in 928 participants from the InCHIANTI study. Dietary intake data were collected using a validated food frequency questionnaire. Urinary TPE was analyzed by Folin–Ciocalteau assay. Both urinary TPE expression models were statistically correlated (r = 0.580), and the partial correlation coefficient improved (pr = 0.722) after adjusting for the variables that modify the urinary creatinine excretion (i.e. gender, age, BMI, physical activity and renal function). In crude models, polyphenol intake was associated with TPE corrected by 24-h volume (r = 0.211; P < 0.001), but not with creatinine normalization (r = 0.014; P = 0.692). However, urinary TPE expressed by creatinine correction was significantly correlated with dietary polyphenols after adjusting for covariates (pr = 0.113; P = 0.002). We conclude that urinary TPE expressed by 24-h volume is a better biomarker of polyphenol dietary intake than by urinary creatinine normalization. After covariate adjustment, both can be used for studying the relationships between polyphenol intake and health in large-scale epidemiological studies.
Polyphenols; Urine 24-h; Creatinine normalization; Biomarker; InCHIANTI study
Several formulas are available to estimate glomerular filtration rate (GFR) at the bedside. A decrease in GFR has been associated with poorer performance. We hypothesized that it is related to worsening disability as well. The aim of this study was to evaluate whether the Modification of Diet in Renal Disease formulas can predict worsening disability better than the classic Cockcroft-Gault formula or the measured creatinine clearance.
We studied 666 participants in the InCHIANTI study with 6 years of follow-up data. We evaluated whether directly measured creatinine clearance and GFR estimated using the Modification of Diet in Renal Disease and Cockcroft-Gault formulas predict new disability defined as the loss of ≥1 ADL over the 6-year follow-up.
The mean age was 73.1 years (SD: 6.1), 57.7% were women. Fewer than 5% of participants were disabled at baseline. Eighty-one (12.2%) participants experienced a decline in activities of daily life score at follow-up. Declining GFR was associated with increasing risk of worsening disability (Mantel-Haenszel P < .001), with an increased steepness in the curve at GFR below 60 mL/min. The relative risks for worsening disability in people with GFR less than 60 mL/min/m were 3.19 (95% CI: 2.12–4.79) and 4.40 (95% CI: 2.80–6.94) using the Modification of Diet in Renal Disease and the Cockcroft-Gault equations, respectively. The corresponding figures obtained with measured creatinine clearance was 3.95 (95% CI: 2.60–6.01). After adjustment for potential confounders, however, these estimates were substantially reduced.
Estimation of renal function with the Cockcroft-Gault or Modification of Diet in Renal Disease formulas can help to identify elderly at risk of worsening disability. The mechanism by which reduced kidney function predicts disability should be further investigated.
Renal function; disability; aged; estimating equations
The growth hormone/insulin‐like growth factor (IGF) axis can be manipulated in animal models to promote longevity, and IGF‐related proteins including IGF‐I and IGF‐binding protein‐3 (IGFBP‐3) have also been implicated in risk of human diseases including cardiovascular diseases, diabetes, and cancer. Through genomewide association study of up to 30 884 adults of European ancestry from 21 studies, we confirmed and extended the list of previously identified loci associated with circulating IGF‐I and IGFBP‐3 concentrations (IGF1, IGFBP3,GCKR,TNS3, GHSR, FOXO3, ASXL2, NUBP2/IGFALS, SORCS2, and CELSR2). Significant sex interactions, which were characterized by different genotype–phenotype associations between men and women, were found only for associations of IGFBP‐3 concentrations with SNPs at the loci IGFBP3 and SORCS2. Analyses of SNPs, gene expression, and protein levels suggested that interplay between IGFBP3 and genes within the NUBP2 locus (IGFALS and HAGH) may affect circulating IGF‐I and IGFBP‐3 concentrations. The IGF‐I‐decreasing allele of SNP rs934073, which is an eQTL of ASXL2, was associated with lower adiposity and higher likelihood of survival beyond 90 years. The known longevity‐associated variant rs2153960 (FOXO3) was observed to be a genomewide significant SNP for IGF‐I concentrations. Bioinformatics analysis suggested enrichment of putative regulatory elements among these IGF‐I‐ and IGFBP‐3‐associated loci, particularly of rs646776 at CELSR2. In conclusion, this study identified several loci associated with circulating IGF‐I and IGFBP‐3 concentrations and provides clues to the potential role of the IGF axis in mediating effects of known (FOXO3) and novel (ASXL2) longevity‐associated loci.
aging; genomewide association study; growth hormone axis; IGF‐I; IGFBP‐3; longevity
The hormone klotho is encoded by aging-suppressor gene klotho and has multiple roles, including regulating mineral (calcium and phosphate) homeostasis. Vitamin D also regulates mineral homeostasis and upregulates klotho expression. Klotho positively relates to longevity, upper-extremity strength, and reduced disability in older adults; however, it is unknown whether circulating klotho relates to lower-extremity physical performance or whether the relation of vitamin D with physical performance is mediated by klotho.
Klotho and 25-hydroxyvitamin D [25(OH)D] were measured in 860 participants aged ≥ 55 years in Invecchiare in Chianti, “Aging in Chianti” (InCHIANTI), a prospective cohort study comprising Italian adults. Lower-extremity physical performance was measured using the Short Physical Performance Battery, a summary score of balance, chair stand ability, and walking speed. Weighted estimating equations related plasma klotho and serum 25(OH)D concentrations measured at one visit to Short Physical Performance Battery measured longitudinally at multiple visits.
Each additional natural log of klotho (pg/mL) was associated with 0.47 higher average Short Physical Performance Battery scores (95% confidence interval: 0.08 to 0.86, p value = .02) after adjustment for covariates, including 25(OH)D. Each natural log of 25(OH)D (ng/mL) was associated with 0.61 higher average Short Physical Performance Battery scores (95% confidence interval: 0.35 to 0.88, p value < .001) after adjustment for covariates, a result that changed little after adjustment for klotho.
Plasma klotho and 25(OH)D both positively related to lower-extremity physical performance. However, the findings did not support the hypothesis that klotho mediates the relation of 25(OH)D with physical performance.
Biomarkers; Epidemiology; Physical f; unction; Metabolism; Physical p; erformance.
Frailty, an age-related state of increased vulnerability, is associated with a higher risk of multiple adverse events. Studies have suggested that the quality of dietary intake may affect the development of frailty. We hypothesized that frailty in older subjects would be associated with dietary total polyphenols (DTP) intake and its biomarker, urinary total polyphenols (UTP).
The Invecchiare in Chianti (InCHIANTI) Study is a prospective cohort study set in the Chianti area (Italy). We used data at baseline from 811 participants aged 65 years and older. UTP was determined using the Folin–Ciocalteu assay after solid-phase extraction. DTP was estimated using a validated Food Frequency Questionnaire and our own polyphenol database. The frailty, prefrailty, and nonfrailty states were defined according to the Fried and colleagues’ criteria. Multinomial logistic regressions adjusted for potential confounders were used to assess the relationship between polyphenols and frailty.
Both DTP and UTP concentrations progressively decrease from nonfrail to frail participants. Participants in the highest UTP tertile compared to those in the lowest tertile were significantly less likely to be both frail (odds ratio [OR] = 0.36 [0.14–0.88], p = .025) and prefrail (OR = 0.64 [0.42–0.98], p = .038). Exhaustion and slowness were the only individual frailty criteria significantly associated with UTP tertiles. No significant association was observed between frailty and DTP, after adjustment for covariates.
High concentrations of UTP were associated with lower prevalence of frailty and prefrailty in an older community-dwelling population. A polyphenol-rich diet may protect against frailty in older persons. Our findings should be confirmed in longitudinal studies.
Frailty; Nutrition; Biomarkers; Polyphenols; Elderly people; InCHIANTI.
Estimates of biological age based on DNA methylation patterns, often referred to as “epigenetic age”, “DNAm age”, have been shown to be robust biomarkers of age in humans. We previously demonstrated that independent of chronological age, epigenetic age assessed in blood predicted all-cause mortality in four human cohorts. Here, we expanded our original observation to 13 different cohorts for a total sample size of 13,089 individuals, including three racial/ethnic groups. In addition, we examined whether incorporating information on blood cell composition into the epigenetic age metrics improves their predictive power for mortality. All considered measures of epigenetic age acceleration were predictive of mortality (p≤8.2×10−9), independent of chronological age, even after adjusting for additional risk factors (p<5.4×10−4), and within the racial/ethnic groups that we examined (non-Hispanic whites, Hispanics, African Americans). Epigenetic age estimates that incorporated information on blood cell composition led to the smallest p-values for time to death (p=7.5×10−43). Overall, this study a) strengthens the evidence that epigenetic age predicts all-cause mortality above and beyond chronological age and traditional risk factors, and b) demonstrates that epigenetic age estimates that incorporate information on blood cell counts lead to highly significant associations with all-cause mortality.
all-cause mortality; lifespan; epigenetics; epigenetic clock; DNA methylation; mortality
Thousand and twelve dementia-free elderly (60–98 years old) enrolled in the In Chianti Study (Italy) were evaluated at baseline (1998–2000) and at 3-year follow-up (2001–2003) with the aim of analyzing the association of lifetime socioeconomic status (SES) with prevalent and incident cognitive impairment no-dementia (CIND). SES was defined from information on formal education, longest held occupation, and financial conditions through life. CIND was defined as age-adjusted Mini-Mental State Examination score one standard deviation below the baseline mean score of participants without dementia. Logistic regression and Cox proportional-hazards models were used to estimate the association of SES with CIND. Demographics, occupation characteristics (i.e., job stress and physical demand), cardiovascular diseases, diabetes, apolipoprotein E (APOE) genotype, smoking, alcohol consumption, depressive symptoms, and C-reactive protein were considered potential confounders. Prevalence of CIND was 17.7%. In the fully adjusted model, low education (OR = 2.1; 95% confidence intervals, CI = 1.4 to 3.2) was associated with prevalent CIND. Incidence rate of CIND was 66.0 per 1000 person-years. Low education (HR = 1.7; 95% CI = 1.04 to 2.6) and manual occupation (HR = 1.9; 95% CI =1.0 to 3.6) were associated with incident CIND. Among covariates, high job-related physical demand was associated with both prevalent and incident CIND (OR = 1.6; 95% CI = 1.1 to 2.4 and HR = 1.5; 95% CI = 1.0 to 2.3). After stratification for education, manual occupation was still associated with CIND among participants with high education (HR = 2.2; 95% CI = 1.2 to 4.3 versus HR = 1.4; 95% CI = 0.2 to 10.4 among those with low education). Proxy markers of lifetime SES (low education, manual occupation and high physical demand) are cross-sectional correlates of CIND and predict incident CIND over a three-year follow-up.
Cognitive impairment no-dementia; epidemiology; education; finances; occupation; socioeconomic status
Recent studies demonstrated that erythropoietin (EPO) have a number of non-erythropoietic effects including neuroprotection and vascular protection.
Using data from a representative sample of older persons, we tested the hypothesis that EPO levels are correlated with peripheral nerve parameters (NVC and CMAP) assessed by surface ENG and with clinically diagnosed polyneuropathy. We selected 972 participants (aged 60–98 years) with complete data for the analyses.
We found a significant association between EPO and age-adjusted NCV and CMAP (for NCV: 0.57 ± 0.26; p = 0.03 and for CMAP: 0.54 ± 0.23; p = 0.02). In logistic regression models adjusting for age, sex and multiple potential confounders, higher EPO levels were associated with a significantly lower probability of having a clinical diagnosis of polyneuropathy (OR = 0.43; 95% CI: 0.22–0.84).
These findings suggest that EPO is implicated in the pathogenesis of polyneuropathy in older persons. Whether low EPO is a risk factor for polyneuropathy should be tested in future longitudinal analyses.
EPO; Polyneuropathy; Prevention; Population-based study; InCHIANTI study
Faster resting heart rate (HR), which is associated with inflammation and elevated cortisol levels, is a risk factor for excess cardiovascular morbidity and mortality. Obesity is associated with increased cardiovascular morbidity and mortality, inflammation, and elevated cortisol levels. The aim of the present study was to evaluate the interaction of Body Mass Index (BMI) with inflammation and cortisol in modulating HR in older subjects.
We analyzed data of 895 participants aged 65+ enrolled in the “InCHIANTI” study, in sinus rhythm, and not taking beta blockers or digoxin. Linear regression was performed to assess the adjusted association between HR, IL-6, and cortisol levels. The model was also analyzed stratifying for BMI tertiles. Logistic regression was adopted for evaluating the association of HR exceeding the mean value with Il-6 and serum cortisol.
According to multivariable linear regression, IL-6 and cortisol levels were associated with HR (B = 1.42, 95% CI = 0.43–2.42; p = .005 and B = .34, 95% CI = 0.17–.51; p < .0001, respectively). The association was significant only among women in the highest BMI tertile (B = 4.16, 95% CI = 1.40–6.91; p = .003 for IL-6 and B = .57, 95% CI = 0.14–1.01; p = .010 for cortisol). Logistic regression confirmed that IL-6 and cortisol levels were associated with HR above the mean value in the highest BMI tertile (OR = 2.13, 95% CI = 1.15–3.97; p = .009 and OR = 1.14, 95% CI = 1.03–1.25; p = .009, respectively).
Faster HR is associated with proinflammatory state in elderly patients; this association seems to be limited to women with higher BMI.
Heart rate; Inflammation; Elderly; Body mass index; Epidemiology
Tissue concentrations of omega-3 fatty acids may reduce cardiovascular disease risk, and genetic variants are associated with circulating fatty acids concentrations. Whether dietary fatty acids interact with genetic variants to modify circulating omega-3 fatty acids is unclear.
We evaluated interactions between genetic variants and fatty acid intakes for circulating alpha-linoleic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA).
Methods and Results
We conducted meta-analyses (N to 11,668) evaluating interactions between dietary fatty acids and genetic variants (rs174538 and rs174548 in FADS1 (fatty acid desaturase 1), rs7435 in AGPAT3 (1-acyl-sn-glycerol-3-phosphate), rs4985167 in PDXDC1 (pyridoxal-dependent decarboxylase domain-containing 1), rs780094 in GCKR (glucokinase regulatory protein) and rs3734398 in ELOVL2 (fatty acid elongase 2)). Stratification by measurement compartment (plasma vs. erthyrocyte) revealed compartment-specific interactions between FADS1 rs174538 and rs174548 and dietary ALA and linoleic acid for DHA and DPA.
Our findings reinforce earlier reports that genetically-based differences in circulating fatty acids may be partially due to differences in the conversion of fatty acid precursors. Further, fatty acids measurement compartment may modify gene-diet relationships, and considering compartment may improve the detection of gene-fatty acids interactions for circulating fatty acid outcomes.
FADS1; gene-diet interactions; meta-analysis; omega-3 fatty acids
Mobility is an essential aspect of everyday life and enables autonomy and participation. Although many risk factors for mobility loss have been previously described, their relative importance and independent contributions to the long-term risk of losing mobility have not been well defined.
This study is based on 1,013 men and women aged ≥65 years enrolled in 1998–2000 and followed for 9 years through 2007–2008 in the population-based InCHIANTI (Invecchiare in Chianti, aging in the Chianti area) study. We considered 44 different measures assessed at baseline to explore six subsystems: (i) central nervous system, (ii) peripheral nervous system, (iii) muscles, (iv) bone and joints, (v) energy production and delivery, and (vi) perceptual system. The outcome was incident mobility loss defined as self-report of inability to walk 400 m or climb and descend 10 steps without help from another person. Random survival forest analysis was used to rank the candidate predictors by their importance.
The most important physiological markers predicting mobility loss that emerged from the random survival forest modeling were older age among women (81–95 vs 65–68 years, hazard ratio [HR] 9.60 [95% CI 3.35, 27.50]), weaker ankle dorsiflexion strength (lowest vs highest quintile, HR 5.25 [95% CI 2.35, 11.72]), low hip flexion range of motion (lowest vs highest quintile, HR 2.30 [95% CI 1.20, 4.41]), presence of primitive reflexes (yes vs no, HR 1.47 [95% CI 1.03, 2.09]), and tremor (yes vs no, HR 1.91 [95% CI 1.18, 3.07]).
Prevention of mobility loss with aging should focus on prevention and treatment of neuromuscular impairments.
Physical functioning; Mobility loss; Physiological markers; Muscle strength; Central nervous system; Random survival forest
Current operational definitions of sarcopenia are based on algorithms’ simultaneous considering measures of skeletal muscle mass and muscle-specific as well as global function. We hypothesize that quantitative and qualitative sarcopenia-related parameters may not be equally predictive of incident disability, thus presenting different clinical relevance.
Data are from 922 elder adults (mean age = 73.9 years) with no activities of daily living (ADL) impairment recruited in the “Invecchiare in Chianti” study. Incident disability in ≥1 ADL defined the outcome of interest. The specific capacities of following sarcopenia-related parameters at predicting incident ADL disability were compared: residuals of skeletal muscle mass, fat-adjusted residuals of skeletal muscle mass, muscle density, ankle extension strength, ratio ankle extension strength/muscle mass, gait speed, and handgrip strength.
During the follow-up (median = 9.1 years), 188 (20.4%) incident ADL disability events were reported. Adjusted models showed that only gait speed was significantly associated with the outcome in both men (per standard deviation [SD] = 0.23 m/s increase, hazard ratio [HR] = 0.46, 95% confidence interval [CI] = 0.33–0.63; p < .001) and women (per SD = 0.24 m/s increase, HR = 0.64, 95% CI = 0.50–0.82; p < .001). In women, the fat-adjusted lean mass residual (per SD = 4.41 increase, HR = 0.79, 95% CI = 0.65–0.96; p = .02) and muscle density (per SD = 3.60 increase, HR = 0.76, 95% CI = 0.61–0.93; p = .01) were the only other parameters that predicted disability. In men, several of the tested variables (except muscle mass measures) reported significant results.
Gender strongly influences which sarcopenia-related parameters predict disability. Gait speed was a powerful predictor of disability in both men and women, but its nonmuscle-specific nature should impose caution about its inclusion in definitions of sarcopenia.
Skeletal muscle; Sarcopenia; Disability; Body composition; Gait speed.
Usual sleep duration is a heritable trait correlated with psychiatric morbidity, cardiometabolic disease and mortality, although little is known about the genetic variants influencing this trait. A genome-wide association study of usual sleep duration was conducted using 18 population-based cohorts totaling 47,180 individuals of European ancestry. Genome-wide significant association was identified at two loci. The strongest is located on chromosome 2, in an intergenic region 35–80 kb upstream from the thyroid-specific transcription factor PAX8 (lowest p=1.1 ×10−9). This finding was replicated in an African-American sample of 4771 individuals (lowest p=9.3 × 10−4). The strongest combined association was at rs1823125 (p=1.5 × 10−10, minor allele frequency 0.26 in the discovery sample, 0.12 in the replication sample), with each copy of the minor allele associated with a sleep duration 3.1 minutes longer per night. The alleles associated with longer sleep duration were associated in previous genome-wide association studies with a more favorable metabolic profile and a lower risk of attention deficit hyperactivity disorder. Understanding the mechanisms underlying these associations may help elucidate biological mechanisms influencing sleep duration and its association with psychiatric, metabolic and cardiovascular disease.
Sleep; Genome-wide association study
Usual sleep duration is a heritable trait correlated with psychiatric morbidity, cardiometabolic disease and mortality, although little is known about the genetic variants influencing this trait. A genome-wide association study of usual sleep duration was conducted using 18 population-based cohorts totaling 47,180 individuals of European ancestry. Genome-wide significant association was identified at two loci. The strongest is located on chromosome 2, in an intergenic region 35-80 kb upstream from the thyroid-specific transcription factor PAX8 (lowest p=1.1 × 10−9). This finding was replicated in an African-American sample of 4771 individuals (lowest p=9.3 × 10−4). The strongest combined association was at rs1823125 (p=1.5 × 10−10, minor allele frequency 0.26 in the discovery sample, 0.12 in the replication sample), with each copy of the minor allele associated with a sleep duration 3.1 minutes longer per night. The alleles associated with longer sleep duration were associated in previous genome-wide association studies with a more favorable metabolic profile and a lower risk of attention deficit hyperactivity disorder. Understanding the mechanisms underlying these associations may help elucidate biological mechanisms influencing sleep duration and its association with psychiatric, metabolic and cardiovascular disease.
Sleep; Genome-wide association study
Multimorbidity increases with aging, but risk factors beyond age are unknown.
To investigate the association of inflammatory and anabolic hormonal biomarkers with presence and prospective development of multimorbidity.
Nine-year longitudinal study of 1018 participants aged 60 years or older (InCHIANTI Study). Multimorbidity was evaluated at baseline and follow-up visits as number of diagnosed diseases from a predefined list of 15 candidate chronic conditions, defined according to standard clinical criteria. Linear mixed models were used to test cross-sectional and longitudinal associations between candidate biomarkers and multimorbidity.
At baseline, multimorbidity was significantly higher in older participants (p < .001) and higher IL-6, IL-1ra, TNF-α receptor II (TNFAR2), and lower dehydroepiandrosterone sulfate were associated with higher number of diseases, independent of age, sex, body mass index, and education. The rate of longitudinal increase in number of chronic diseases was significantly steeper in participants who were older at baseline (p < .001). In addition, higher baseline IL-6 and steeper increase of IL-6 levels were significantly and independently associated with a steeper increase in multimorbidity over time (p < .001 and p = .003, respectively). Sensitivity analyses, performed using 15 different models obtained by removing each of 15 conditions included in the original list of candidate diseases, confirmed that results were not driven by any specific condition.
Accumulation of chronic diseases accelerates at older ages and in persons with higher baseline levels and steeper increase over time of IL-6. High IL-6 and increase in IL-6 may serve as early warning sign to better target interventions aimed at reducing the burden of multimorbidity.
Multimorbidity; Inflammation; Interleukin-6; Aging; Chronic diseases.
The genetic contribution to longevity in humans has been estimated to range from 15% to 25%. Only two genes, APOE and FOXO3, have shown association with longevity in multiple independent studies.
We conducted a meta-analysis of genome-wide association studies including 6,036 longevity cases, age ≥90 years, and 3,757 controls that died between ages 55 and 80 years. We additionally attempted to replicate earlier identified single nucleotide polymorphism (SNP) associations with longevity.
In our meta-analysis, we found suggestive evidence for the association of SNPs near CADM2 (odds ratio [OR] = 0.81; p value = 9.66 × 10−7) and GRIK2 (odds ratio = 1.24; p value = 5.09 × 10−8) with longevity. When attempting to replicate findings earlier identified in genome-wide association studies, only the APOE locus consistently replicated. In an additional look-up of the candidate gene FOXO3, we found that an earlier identified variant shows a highly significant association with longevity when including published data with our meta-analysis (odds ratio = 1.17; p value = 1.85×10−10).
We did not identify new genome-wide significant associations with longevity and did not replicate earlier findings except for APOE and FOXO3. Our inability to find new associations with survival to ages ≥90 years because longevity represents multiple complex traits with heterogeneous genetic underpinnings, or alternatively, that longevity may be regulated by rare variants that are not captured by standard genome-wide genotyping and imputation of common variants.
Longevity; GWAS; FOXO3; APOE.
Falls are a common, serious threat to the health and self-confidence of the elderly. Assessment of fall risk is an important aspect of effective fall prevention programs.
Objectives and methods
In order to test whether it is possible to outperform current prognostic tools for falls, we analyzed 1010 variables pertaining to mobility collected from 976 elderly subjects (InCHIANTI study). We trained and validated a data-driven model that issues probabilistic predictions about future falls. We benchmarked the model against other fall risk indicators: history of falls, gait speed, Short Physical Performance Battery (Guralnik et al. 1994), and the literature-based fall risk assessment tool FRAT-up (Cattelani et al. 2015). Parsimony in the number of variables included in a tool is often considered a proxy for ease of administration. We studied how constraints on the number of variables affect predictive accuracy.
The proposed model and FRAT-up both attained the same discriminative ability; the area under the Receiver Operating Characteristic (ROC) curve (AUC) for multiple falls was 0.71. They outperformed the other risk scores, which reported AUCs for multiple falls between 0.64 and 0.65. Thus, it appears that both data-driven and literature-based approaches are better at estimating fall risk than commonly used fall risk indicators. The accuracy–parsimony analysis revealed that tools with a small number of predictors (~1–5) were suboptimal. Increasing the number of variables improved the predictive accuracy, reaching a plateau at ~20–30, which we can consider as the best trade-off between accuracy and parsimony. Obtaining the values of these ~20–30 variables does not compromise usability, since they are usually available in comprehensive geriatric assessments.
White blood cell (WBC) count is a common clinical measure used as a predictor of certain aspects of human health, including immunity and infection status. WBC count is also a complex trait that varies among individuals and ancestry groups. Differences in linkage disequilibrium structure and heterogeneity in allelic effects are expected to play a role in the associations observed between populations. Prior genome-wide association study (GWAS) meta-analyses have identified genomic loci associated with WBC and its subtypes, but much of the heritability of these phenotypes remains unexplained. Using GWAS summary statistics for over 50 000 individuals from three diverse populations (Japanese, African-American and European ancestry), a Bayesian model methodology was employed to account for heterogeneity between ancestry groups. This approach was used to perform a trans-ethnic meta-analysis of total WBC, neutrophil and monocyte counts. Ten previously known associations were replicated and six new loci were identified, including several regions harboring genes related to inflammation and immune cell function. Ninety-five percent credible interval regions were calculated to narrow the association signals and fine-map the putatively causal variants within loci. Finally, a conditional analysis was performed on the most significant SNPs identified by the trans-ethnic meta-analysis (MA), and nine secondary signals within loci previously associated with WBC or its subtypes were identified. This work illustrates the potential of trans-ethnic analysis and ascribes a critical role to multi-ethnic cohorts and consortia in exploring complex phenotypes with respect to variants that lie outside the European-biased GWAS pool.