Objectives

To evaluate the relationship between life-space mobility (extent, frequency, independence of movement) and mortality in older women.

Design

Prospective cohort study.

Setting

Four U.S. clinical sites.

Participants

Women (N = 1,498) aged 75 to 102 (mean 87.6) followed from 2006 to 2015.

Measurements

Life-space during the past 4 weeks was assessed in an interview, scored from 0 (daily restriction to bedroom) to 120 (daily trips outside town without assistance), and categorized (0-20, 21-40, 41-60, 61-80, 81-120). All-cause mortality was the primary outcome; noncancer, cardiovascular, cancer, and noncardiovascular noncancer mortality were secondary outcomes.

Results

Over a mean 5.2 years, 842 (56.2%) women died. Unadjusted risk of all-cause mortality was 82.6% in women with the lowest level of life-space (0-20 points) and 36.2% in those with the highest level (81-120 points). In multivariable proportional hazards models, there was a strong relationship between less life-space and greater risk of all-cause mortality (P_trend < .001). Women with the lowest level of life-space (0-20 points) had a risk of all-cause mortality that was 2.4 times as high (95% confidence interval (CI) = 1.5-4.0) as that of women with the highest level (81-120 points); women with life-space scores between 21 and 60 had a risk of all-cause mortality that was 1.5 times as high as that of women with the highest level. Each standard deviation decrease in life-space was associated with a 1.2 times greater (95% CI = 1.1-1.4) risk of all-cause mortality. Women unable to travel beyond their neighborhood without assistance had a risk of all-cause mortality that was 1.4 times (95% CI = 1.1-1.7) as high as that of women who could travel beyond their neighborhood without assistance. Results were similar for noncancer, cardiovascular, and other mortality and did not change after controlling for underlying disease or living arrangement.

Conclusion

Life-space scores of 60 or less were associated with mortality in older women independent of other strong risk factors.

Objectives

To evaluate the relationship between life-space (the extent, frequency, and independence of an individual's movement) and mortality in older men.

Design

Prospective cohort study.

Setting

Six U.S. clinical sites.

Participants

Men aged 71 to 98 followed from 2007 to 2011 (N = 3,892).

Measurements

Life-space during the past month was assessed as 0 (daily restriction to one's bedroom) to 120 (daily trips outside one's town without assistance) and categorized into 20-point intervals. The primary outcome was noncancer mortality, and secondary outcomes were all-cause, cardiovascular, cancer, and noncardiovascular noncancer mortality.

Results

Over 2.7 years (2007-2011), 373 (9.6%) men died, 230 from noncancer causes. Unadjusted risk of noncancer mortality was 41.2% in men with the lowest level of life-space (0-20 points, n = 34) and 2.4% in men with the highest level of life-space (101-120 points, n = 868), a 17 times difference. In multivariable-adjusted models, there was a strong linear trend between decreasing life-space and increasing risk of noncancer mortality (P = .005). Risk of noncancer mortality was 3.8 times higher (95% confidence interval (CI)=1.3,11.5) in men with the lowest life-space than in those with the highest life-space. Risk of noncancer mortality was 1.3 times higher (95% CI=1.1-1.5) for each standard-deviation (24 point) decrease in life-space. Risk of noncancer mortality was 1.5 times higher (95% CI=1.0-2.3) in men who did not travel beyond their neighborhood without assistance (n = 471). Results were similar for all-cause mortality and did not change after control for chronic disease burden.

Conclusion

Life-space predicted a variety of mortality endpoints in older men; scores of 40 or less were associated with mortality independent of other risk factors.

Background

Total daily energy expenditure (TEE) is composed of resting metabolic rate (RMR), post-prandial thermogenesis and activity energy expenditure (AEE). Higher AEE is strongly associated with lower mortality and physical limitations among older adults, but factors that predict changes in AEE in septu and octogenarians are not clearly understood.

Objective

To identify factors associated with late-life longitudinal change in AEE.

Design

Energy expenditure was re-assessed in 83 participants (average age at baseline, 74.4±3.2 years)-an average of 7.5±0.54 years since the baseline measure. RMR was measured using indirect calorimetry and the thermic effect of meals was estimated at 10% of TEE. AEE was calculated as: TEE(0.9)-RMR. Participants were categorized into two groups according to the estimated day-to-day precision of the doubly-labeled water technique. Those who were within 10% or increased relative to their initial AEE measurement were categorized as having preserved AEE. Participants who declined greater than 10% of their initial measurement were categorized as having reduced AEE. A variety of socio-demographic, functional and mental factors, body composition, community and personal behaviors, blood measurements and health conditions were evaluated between groups at baseline and changes during follow-up.

Results

Daily AEE declined 106.61±293.25 kcal, which equated to a 14.63±40.57 kcal/d decrease per year. Fifty-nine percent (n = 49) preserved their AEE and 41% (n = 34) declined. Those who demonstrated a decline in AEE were older, had lower walking speed at baseline and showed a higher lean mass loss during follow up. Otherwise, groups were similar for socio-demographic characteristics, body composition, mental and physical function, health conditions and community and personal behaviors at baseline and change in these factors during follow-up.

Conclusions

This study demonstrates that AEE declines through the 8th decade of life and is associated with age, lower walking speed at baseline and lean mass loss. Additionally, there are a significant number of individuals who appear to be resilient to these declines despite having health events that are expected to have a negative impact on their physical activity.

To examine the degree of trauma in major osteoporotic fractures (MOF) in men versus women, we used data from 15,698 adults aged ≥65 years enrolled in the Osteoporotic Fractures in Men (MrOS) study (5994 men) and the Study of Osteoporotic Fractures (SOF) (9704 women). Participants were contacted tri-annually to ascertain incident fractures, which were confirmed by radiographic reports and coded according to degree of self-reported trauma. Trauma was classified as low (fall from ≤ standing height; fall on stairs, steps, or curb; minimal trauma other than fall [coughing, turning over]); moderate (collisions with objects during normal activity without associated fall); or high (fall from > standing height; severe trauma [motor vehicle accident, assault]). MOF included hip, clinical vertebral, wrist, and humerus fractures. Mean fracture follow-up was 9.1 years in SOF and 8.7 years in MrOS. A total of 14.6% of the MOF in men versus 6.3% of the MOF in women were classified as high trauma (p < 0.001); men versus women more often experienced fractures resulting from severe trauma as well as from fall > standing height. High-trauma fractures were more significantly common in men versus women at the hip (p = 0.002) and wrist (p < 0.001) but not at the spine or humerus. Among participants with MOF, the odds ratio of a fracture related to high-trauma fracture among men versus women was 3.12 (95% confidence interval [CI] 1.70-5.71) after adjustment for traditional risk factors. Findings were similar in analyses limited to participants with hip fractures (odds ratio [OR] = 3.34, 95% CI 1.04-10.67) and those with wrist fracture (OR = 5.68, 95% CI 2.03-15.85). Among community-dwelling older adults, MOF are more likely to be related to high trauma in men than in women. These findings are not explained by sex differences in conventional risk factors and may reflect a greater propensity among men to engage in risky behavior. © 2015 American Society for Bone and Mineral Research.

Low bone mineral density (BMD) increases fracture risk; how changes in BMD influence fracture risk in older men is uncertain. BMD was assessed at two to three time points over 4.6 years using dual-energy X-ray absorptiometry (DXA) for 4470 men aged ≥65 years in the Osteoporotic Fractures in Men (MrOS) Study. Change in femoral neck BMD was estimated using mixed effects linear regression models. BMD change was categorized as "accelerated" (≤-0.034 g/cm(2) ), "expected" (between 0 and -0.034 g/cm(2) ), or "maintained" (≥0 g/cm(2) ). Fractures were adjudicated by central medical record review. Multivariate proportional hazards models estimated the risk of hip, nonspine/nonhip, and nonspine fracture over 4.5 years after the final BMD measure, during which time 371 (8.3%) men experienced at least one nonspine fracture, including 78 (1.7%) hip fractures. Men with accelerated femoral neck BMD loss had an increased risk of nonspine (hazard ratio [HR] = 2.0; 95% confidence interval [CI] 1.4-2.8); nonspine/nonhip (HR = 1.6; 95% CI 1.1-2.3); and hip fracture (HR = 6.3; 95% CI 2.7-14.8) compared with men who maintained BMD over time. No difference in risk was seen for men with expected loss. Adjustment for the initial BMD measure did not alter the results. Adjustment for the final BMD measure attenuated the change in BMD-nonspine fracture and the change in BMD-nonspine/nonhip relationships such that they were no longer significant, whereas the change in the BMD-hip fracture relationship was attenuated (HR = 2.6; 95% CI 1.1-6.4). Total hip BMD change produced similar results. Accelerated decrease in BMD is a strong, independent risk factor for hip and other nonspine fractures in men.

Abstract Background Very little is known about the longitudinal changes in energy requirements in late life. The purposes of this study were to: (1) determine the energy requirements in late life and how they changed during a 7 year time-span, (2) determine whether changes in fat free mass (FFM) were related to changes in resting metabolic rate (RMR), and (3) determine the accuracy of predicted total energy expenditure (TEE) to measured TEE. Methods TEE was assessed via doubly labeled water (DLW) technique in older adults in both 1999 (n = 302; age: 74 ± 2.9 yrs) and again in 2006 (n = 87 age: 82 ± 3.1 yrs). RMR was measured with indirect calorimetry, and body composition was assessed with dual-energy x-ray absorptiometry. Results The energy requirements in the 9th decade of life were 2208 ± 376 kcal/d for men and 1814 ± 337 kcal/d for women. This was a significant decrease from the energy requirements in the 8th decade of life in men (2482 ± 476 kcal/d vs. 2208 ± 376 kcal/d) but not in women (1892 ± 271 kcal/d vs. 1814 ± 337 kcal/d). In addition to TEE, RMR, and activity EE (AEE) also decreased in men, but not women, while FFM decreased in both men and women. The changes in FFM were correlated with changes in RMR for men (r = 0.49, p < 0.05) but not for women (r = −0.08, ns). Measured TEE was similar to Dietary Reference Intake (DRI) predicted TEE for men (2208 ± 56 vs. 2305 ± 35 kcal/d) and women (1814 ± 42 vs. 1781 ± 20 kcal/d). However, measured TEE was different than the World Health Organization (WHO) predicted TEE in men (2208 ± 56 vs. 2915 ± 31 kcal/d (p < 0.05)) and women (1814 ± 42 vs. 2315 ± 21 kcal/d (p < 0.05)). Conclusions TEE, RMR and AEE decreased in men, but not women, from the 8th to 9th decade of life. The DRI equation to predict TEE was comparable to measured TEE, while the WHO equation over-predicted TEE in our elderly population.

Objectives

To examine associations between objective measures of activity level and mortality risk in older men.

Design

Prospective cohort study.

Setting

Six U.S. sites.

Participants

Men aged 71 and older followed an average of 4.5 years (N = 2,918).

Measurements

Time awake spent in sedentary behavior (metabolic equivalent (MET) level ≤1.50), light activity (MET level 1.51-2.99), and at least moderate activity (MET level ≥3.00) measured using an activity monitor worn for 5 days or longer and expressed as quartiles. Deaths were confirmed with death certificates; cause of death was adjudicated by review of certificates and records.

Results

During follow-up, 409 (14%) men died. After multivariable adjustment, comparing Q4 with Q1, more time spent in sedentary behavior (Q4 vs Q1, hazard ratio (HR) = 1.51, 95% confidence interval (CI) = 1.10-2.08), less time spent in light activity (Q1 vs Q4, HR = 1.54, 95% CI = 1.06-2.24), and less time spent in at least moderate activity (Q1 vs Q4, HR = 1.56, 95% CI = 1.09-2.25) were similarly associated with greater mortality risk primarily due to higher risks of cardiovascular and noncardiovascular, noncancer death. The association between time spent in sedentary behavior and mortality varied according to time spent at higher activity level. More time spent in sedentary behavior was associated with greater risk of death in men spending 1.2 (median) h/d or more in at least moderate activity (Q4 vs Q1, HR = 2.09, 95% CI = 1.26-3.49) but not in those spending less time (Q4 vs Q1, HR = 1.02, 95% CI = 0.62-1.66) (P = .005 for interaction).

Conclusion

In older men exceeding current guidelines on physical activity, more time spent in sedentary behavior is associated with greater mortality risk.

Background

Lower ambulatory performance with aging may be related to a reduced oxidative capacity within skeletal muscle. This study examined the associations between skeletal muscle mitochondrial capacity and efficiency with walking performance in a group of older adults.

Methods

Thirty-seven older adults (mean age 78 years; 21 men and 16 women) completed an aerobic capacity (VO2 peak) test and measurement of preferred walking speed over 400 m. Maximal coupled (State 3; St3) mitochondrial respiration was determined by high-resolution respirometry in saponin-permeabilized myofibers obtained from percutanous biopsies of vastus lateralis (n = 22). Maximal phosphorylation capacity (ATPmax) of vastus lateralis was determined in vivo by (31)P magnetic resonance spectroscopy (n = 30). Quadriceps contractile volume was determined by magnetic resonance imaging. Mitochondrial efficiency (max ATP production/max O2 consumption) was characterized using ATPmax per St3 respiration (ATPmax/St3).

Results

In vitro St3 respiration was significantly correlated with in vivo ATPmax (r (2) = .47, p = .004). Total oxidative capacity of the quadriceps (St3*quadriceps contractile volume) was a determinant of VO2 peak (r (2) = .33, p = .006). ATPmax (r (2) = .158, p = .03) and VO2 peak (r (2) = .475, p < .0001) were correlated with preferred walking speed. Inclusion of both ATPmax/St3 and VO2 peak in a multiple linear regression model improved the prediction of preferred walking speed (r (2) = .647, p < .0001), suggesting that mitochondrial efficiency is an important determinant for preferred walking speed.

Conclusions

Lower mitochondrial capacity and efficiency were both associated with slower walking speed within a group of older participants with a wide range of function. In addition to aerobic capacity, lower mitochondrial capacity and efficiency likely play roles in slowing gait speed with age.