Antioxidant enzymes play an important role in the defense against oxidative stress in the lung and in the pathogenesis of chronic obstructive pulmonary disease (COPD). Sequence variation in genes encoding antioxidant enzymes may alter susceptibility to COPD by affecting longitudinal change in lung function in adults. We genotyped 384 sequence variants in 56 candidate genes in 1281 African American and 1794 European American elderly adults in the Health, Aging, and Body Composition study. Single-marker associations and gene-by-smoking interactions with rate of change in FEV₁ and FEV₁/FVC were evaluated using linear mixed-effects models, stratified by race/ethnicity. In European Americans, rs17883901 in GCLC was statistically significantly associated with rate of change in FEV₁/FVC; the recessive genotype (TT) was associated with a 0.9% per year steeper decline (P = 4.50 × 10(-5)). Statistically significant gene-by-smoking interactions were observed for variants in two genes in European Americans: the minor allele of rs2297765 in mGST3 attenuated the accelerated decline in FEV₁/FVC in smokers by 0.45% per year (P = 1.13 × 10(-4)); for participants with greater baseline smoking pack-years, the minor allele of rs2073192 in IDH3B was associated with an accelerated decline in FEV₁/FVC (P = 2.10 × 10(-4)). For both genes, nominally significant interactions (P < 0.01) were observed at the gene level in African Americans (P = 0.007 and 4.60 × 10(-4), respectively). Nominally significant evidence of association was observed for variants in SOD3 and GLRX2 in multiple analyses. This study identifies two novel genes associated with longitudinal lung function phenotypes in both African and European Americans and confirms a prior finding for GCLC. These findings suggest novel mechanisms and molecular targets for future research and advance the understanding of genetic determinants of lung function and COPD risk.

Background

Maintaining cognitive function protects older adults from developing functional decline. This study aims to identify the neuroimaging correlates of maintenance of higher global cognition as measured by the Modified Mini Mental State Test (3 MS) score.

Methods

Repeated 3 MS measures from 1997-98 through 2006-07 and magnetic resonance imaging with diffusion tensor in 2006-07 were obtained in a biracial cohort of 258 adults free from dementia (mean age 82.9 years, 56% women, 42% blacks). Participants were classified as having shown either maintenance (3 MS slope>0) or decline (3 MS slope<1 SD below the mean) of cognition using linear mixed models. Measures of interest were white matter hyperintensity volume (WMHv) from total brain, volume of the gray matter (GMv) and microstructure (mean diffusivity, MD) for total brain and for brain areas known to be related to memory and executive control function: medial temporal area (hippocampus, parahippocampus and entorhinal cortex), cingulate cortex, dorsolateral prefrontal and posterior parietal cortex.

Results

Differences between cognitive maintainers (n=153) and non-maintainers (n=107) were significant for GMv of the medial temporal area (35.8%, p=0.004) and lower MD of the cingulate cortex (37.9%, p=0.008), but not for other neuroimaging markers. In multivariable regression models adjusted for age, race, WMHv and GMV from the total brain and vascular conditions, each standard deviation of GMv of the medial temporal area and each standard deviation of MD of the cingulate cortex were associated with a nearly 4 times greater probability (odds ratio [standard deviation]: 3.80 [1.16, 12.44]) and a 34% lower probability (0.66, [0.46, 0.97]) of maintaining cognitive function, respectively. In these models neither WMHv nor GMv from total brain were significantly associated with probability of maintaining cognitive function.

Conclusions

Preserving the volume of the medial temporal area and the microstructure of the cingulate cortex may contribute to maintaining cognitive function late in life.

Mid-thigh cross-sectional muscle area (CSA), muscle attenuation, and greater trochanter soft tissue thickness have been shown to be independent risk factors of hip fracture. Our aim was to determine whether muscle and adipose tissue measures derived from dual-energy X-ray absorptiometry (DXA) scans would have a similar risk association as those measured using other imaging methods. Using a case-cohort study design, we identified 169 incident hip fracture cases over an average of 13.5 years among participants from the Health ABC Study, a prospective study of 3075 individuals initially aged 70 to 79 years. We modeled the thigh 3D geometry and compared DXA and computed tomography (CT) measures. DXA-derived thigh CSA, muscle attenuation, and subcutaneous fat thickness were found to be highly correlated to their CT counterparts (Pearson's r = 0.82, 0.45, and 0.91, respectively; p < 0.05). The fracture risk of men and women were calculated separately. We found that decreased subcutaneous fat, CT thigh muscle attenuation, and appendicular lean mass by height squared (ALM/Ht(2)) were associated with fracture risk in men; hazard ratios (HR) = 1.44 (1.02, 2.02), 1.40 (1.05, 1.85), and 0.58 (0.36, 0.91), respectively, after adjusting for age, race, clinical site, body mass index (BMI), chronic disease, hip bone mineral density (BMD), self-reported health, alcohol use, smoking status, education, physical activity, and cognitive function. In a similar model for women, only decreases in subcutaneous fat and DXA CSA were associated with hip fracture risk; HR = 1.39 (1.07, 1.82) and 0.78 (0.62, 0.97), respectively. Men with a high ALM/Ht(2) and low subcutaneous fat thickness had greater than 8 times higher risk for hip fracture compared with those with low ALM/Ht(2) and high subcutaneous fat. In women, ALM/Ht(2) did not improve the model when subcutaneous fat was included. We conclude that the DXA-derived subcutaneous fat thickness is a strong marker for hip fracture risk in both men and women, especially in men with high ALM/Ht(2).

Objectives

To identify novel modifiable risk factors, focusing on oral hygiene, for pneumonia requiring hospitalization of community-dwelling older adults.

Design

Prospective observational cohort study.

Setting

Memphis, Tennessee, and Pittsburgh, Pennsylvania.

Participants

Of 3,075 well-functioning community-dwelling adults aged 70 to 79 enrolled in the Health, Aging, and Body Composition Study from 1997 to 1998, 1,441 had complete data in the data set of all variables used, a dental examination within 6 months of baseline, and were eligible for this study.

Measurements

The primary outcome was pneumonia requiring hospitalization through 2008.

Results

Of 1,441 participants, 193 were hospitalized for pneumonia. In a multivariable model, male sex (hazard ratio (HR) = 2.07, 95% confidence interval (CI) = 1.51-2.83), white race (HR = 1.44, 95% CI = 1.03-2.01), history of pneumonia (HR = 3.09, 95% CI = 1.86-5.14), pack-years of smoking (HR = 1.006, 95% CI = 1.001-1.011), and percentage of predicted forced expiratory volume in 1 minute (moderate vs mild lung disease or normal lung function, HR = 1.78, 95% CI = 1.28-2.48; severe lung disease vs mild lung disease or normal lung function, HR = 2.90, 95% CI = 1.51-5.57) were nonmodifiable risk factors for pneumonia. Incident mobility limitation (HR = 1.77, 95% CI = 1.32-2.38) and higher mean oral plaque score (HR = 1.29, 95% CI = 1.02-1.64) were modifiable risk factors for pneumonia. Average attributable fractions revealed that 11.5% of cases of pneumonia were attributed to incident mobility limitation and 10.3% to a mean oral plaque score of 1 or greater.

Conclusion

Incident mobility limitation and higher mean oral plaque score were two modifiable risk factors that 22% of pneumonia requiring hospitalization could be attributed to. These data suggest innovative opportunities for pneumonia prevention among community-dwelling older adults.

Introduction

Data on the association between exercise capacity and risk for heart failure (HF) in older adults are limited.

Methods

This study examined the association of exercise capacity, and its change over time, with 10-year mortality and incident HF in 2,935 participants of the Health, Aging, and Body Composition Study without HF at baseline (age, 73.6 [SD=2.9] years; 52.1% women; 41.4% black; 58.6% white). This cohort was initiated in 1997-1998 and exercise capacity was evaluated with a long-distance corridor walk test (LDCW) at baseline and Year 4. Outcomes were collected in 2007-2008 and initial analysis performed in 2014.

Results

Ten-year incident HF for completers (n=2,245); non-completers (n=331); and those excluded from LDCW for safety reasons (n=359) was 11.4%, 19.2%, and 23.0%, respectively. The corresponding 10-year mortality was 27.9%, 41.1%, and 42.4%. In models accounting for competing mortality, the adjusted subhazard ratio for HF was 1.37 (95% CI=1.00, 1.88; p=0.049) in non-completers and 1.41 (95% CI=1.06, 1.89; p=0.020) in those excluded versus completers. Non-completers (adjusted hazard ratio, 1.49; 95% CI=1.21, 1.84; p<0.001) and those excluded (hazard ratio, 1.27; 95% CI=1.04, 1.55; p=0.016) had elevated mortality. In adjusted models, LDCW performance variables were associated mainly with mortality. Only 20-meter walking speed and resting heart rate retained prognostic value for HF. Longitudinal changes in LDCW did not predict subsequent incident HF or mortality.

Conclusions

Completing an LDCW is strongly associated with lower 10-year mortality and HF risk in older adults. Therefore, walking capacity may serve as an early risk marker.

Objective

The objective of the study is was investigate the association between hearing impairment and anxiety.

Method

We conducted a cross-sectional analysis of 1,732 community-based adults aged 76 to 85 years who participated in the Health Aging and Body Composition (ABC) study. Logistic regression models were adjusted for demographic and cardiovascular risk factors. Hearing impairment was defined by the speech-frequency pure tone average. Anxiety was defined as reporting two symptoms of at least "a little" or one symptom "quite a bit" on the three-item Hopkins Symptom Checklist.

Results

Compared with individuals with no hearing impairment, the odds of prevalent anxiety were higher among individuals with mild hearing impairment (odds ratio [OR] = 1.32, 95% confidence interval [CI] = [1.01, 1.73]) and moderate or greater hearing impairment (OR = 1.59, 95% CI = [1.14, 2.22]). Hearing aid use was not significantly associated with lower odds of anxiety.

Discussion

Hearing impairment is independently associated with greater odds of anxiety symptoms in older adults.

Elevated levels of the phosphate-regulating hormone fibroblast growth factor 23 (FGF23) have been linked to greater risk of fractures in some studies, especially among individuals with chronic kidney disease (CKD). We evaluated FGF23 as a risk factor for bone loss and fractures in the Health, Aging, and Body Composition (Health ABC) study, which is a prospective biracial cohort of well-functioning adults aged 70 to 79 years recruited at two clinical centers in the United States. The sample for the bone mineral density (BMD) analyses consisted of 2234 participants who had at least two serial total hip areal BMD measures. The fracture analyses included 2786 participants, 567 of whom sustained a fracture during a median follow up of 4.95 years. Linear mixed-effects models were used for longitudinal measurements of total hip areal BMD and the proportional subdistribution hazard regression model subject to competing risks of death was used for risk of fracture. The median FGF23 was 46.7 (interquartile range [IQR] 36.7 to 60.2) pg/mL. The mean annualized percent change in total hip areal BMD did not vary significantly according to FGF23 quartile in all participants (p for trend = 0.70), but the effect was modified by CKD status (adjusted p for interaction <0.001). Among participants with CKD, the unadjusted mean annualized percent change in total hip areal BMD was greater with higher levels of FGF23 (unadjusted p for trend = 0.02), but the trend was attenuated with adjustment for estimated glomerular filtration rate and parathyroid hormone (adjusted p for trend = 0.30). FGF23 was not significantly associated with fracture risk in crude (hazard ratio [HR] per doubling of FGF23, 0.97; 95% CI, 0.85 to 1.12) or adjusted models (HR per doubling of FGF23, 1.02; 95% CI, 0.86 to 1.22), and these findings were not modified by gender or CKD status. FGF23 levels are not associated with bone loss or fracture risk in older adults with low prevalence of CKD.

A positive association between cardiorespiratory fitness (CRF) and white matter integrity has been consistently reported in older adults. However, it is unknown whether this association exists in adults over 80 with a range of chronic disease conditions and low physical activity participation, which can influence both CRF and brain health. This study examined whether higher CRF was associated with greater microstructural integrity of gray and white matter in areas related to memory and information processing in adults over 80 and examined moderating effects of chronic diseases and physical activity. CRF was measured as time to walk 400 m as quickly as possible with concurrent 3T diffusion tensor imaging in 164 participants (57.1% female, 40.3% black). Fractional anisotropy (FA) was computed for cingulum, uncinate and superior longitudinal fasciculi. Mean diffusivity (MD) was computed for dorsolateral prefrontal cortex, hippocampus, parahippocampus, and entorhinal cortex. Moderating effects were tested using hierarchical regression models. Higher CRF was associated with higher FA in cingulum and lower MD in hippocampus and entorhinal cortex (β, sex-adjusted p: -0.182, 0.019; 0.165, 0.035; and 0.220, 0.006, respectively). Hypertension attenuated the association with MD in entorhinal cortex. Moderating effects of chronic diseases and physical activity in walking and climbing stairs on these associations were not significant. The association of higher CRF with greater microstructural integrity in selected subcortical areas appears robust, even among very old adults with a range of chronic diseases. Intervention studies should investigate whether increasing CRF can preserve memory and information processing by improving microstructure and potential effects of hypertension management.

Step length variability (SLV) increases with age in those without overt neurologic disease, is higher in neurologic patients, is associated with falls, and predicts dementia. Whether higher SLV in older adults without neurologic disease indicates presence of neurologic abnormalities is unknown. Our objective was to identify whether SLV in older adults without overt disease is associated with findings from multimodal neuroimaging. A well-characterized cohort of 265 adults (79-90 years) was concurrently assessed by gait mat, magnetic resonance imaging with diffusion tensor, and neurological exam. Linear regression models adjusted for gait speed, demographic, health, and functional covariates assessed associations of MRI measures (gray matter volume, white matter hyperintensity volume, mean diffusivity, fractional anisotropy) with SLV. Regional distribution of associations was assessed by sparse partial least squares analyses. Higher SLV (mean: 8.4, SD: 3.3) was significantly associated with older age, slower gait speed, and poorer executive function and also with lower gray matter integrity measured by mean diffusivity (standardized beta=0.16; p=0.02). Associations between SLV and gray matter integrity were strongest for the hippocampus and anterior cingulate gyrus (both β=0.18) as compared to other regions. Associations of SLV with other neuroimaging markers were not significant. Lower integrity of normal-appearing gray matter may underlie higher SLV in older adults. Our results highlighted the hippocampus and anterior cingulate gyrus, regions involved in memory and executive function. These findings support previous research indicating a role for cognitive function in motor control. Higher SLV may indicate focal neuropathology in those without diagnosed neurologic disease.

Aims

The contribution of heart failure (HF) unrelated to vascular disease to the overall HF burden in older adults is not well characterized. This was investigated in this study.

Methods and results

We assessed HF incidence and outcomes in 2895 participants of the Health ABC Study (age 74 ± 3 years, 48.4% men, 41.4% black) in relation to vascular disease (coronary, peripheral, or cerebrovascular disease) either present at baseline or developed prior to HF. During 11.4 years follow-up, 493 participants developed HF; 134 (27.2%) in participants without any prior vascular disease and 177 (36.8%) without coronary disease. Both baseline [hazard ratio (HR) 2.4, 95% confidence interval (CI) 1.9-2.8] and incident vascular disease (HR 4.3, 95% CI 3.6-5.2) were associated with HF. During a median follow-up of 2.1 years after HF onset, 67.5% participants died. Annual mortality after HF development was 21.3% in those with compared with 24.6% in those without vascular disease (HR 1.11, 95% CI 0.87-1.43; P = 0.399). There were 658 all-cause (436.3/1000 person-years) and 523 HF-related (346.4/1000 person-years) hospitalizations after HF development. There was no significant difference in hospitalizations between those with and without vascular disease [rate ratio (RR) 1.04, 95% CI 0.86-1.24 for all-cause, and RR 0.84 95% CI 0.69-1.02 for HF hospitalization]. HF with preserved EF was more common in participants without vascular disease (67.0% vs. 55.0%, P = 0.040).

Conclusion

A significant proportion of HF in older adults develops without prior vascular disease. Outcomes for these patients are poor compared with those with preceding vascular disease. These data suggest the need for more targeted HF prediction and prevention efforts.