Predictors of long-term mortality in the elderly: the Dubbo Study

Mortality, falls and slow walking speed are predicted by different muscle strength and physical performance measures in women and men

BACKGROUND

Different measures of muscle strength, physical performance and body size/composition are used in various sarcopenia definitions. This study investigated which baseline measures best predict incident mortality and falls, and prevalent slow walking speed in older women and men.

MATERIALS AND METHODS

Data for 899 women (mean age±standard deviation, 68.7 ± 4.3 years) and 497 men (69.4 ± 3.9 years) from the Dubbo Osteoporosis Epidemiology Study 2, comprising sixty variables for muscle strength (quadriceps strength), physical performance (walking speed, timed up and go (TUG) test, sit to stand (STS) test), body size (weight, height, body mass index) and body composition (lean mass, body fat) were included. Sex-stratified Classification and Regression Tree (CART) analyses calculated baseline variable accuracy for predicting incident mortality and falls, and prevalent slow walking speed (<0.8 m/s).

RESULTS

Over 14.5 years, 103/899 (11.5%) women and 96/497 (19.3%) men died, 345/899 (38.4%) women and 172/497 (34.6%) men had ≥1 fall, and 304/860 (35.3%) women and 172/461 (31.7%) had baseline slow walking speed (<0.8 m/s). CART models identified age and walking speed adjusted for height as the most important predictors for mortality in women, and quadriceps strength (with adjustments) as the most important predictor for mortality in men. In both sexes, STS (with adjustments) was the most important predictor for incident falls, and TUG test was the most important predictor for prevalent slow walking speed. Body composition measures were not important predictors for any outcome.

CONCLUSIONS

Muscle strength and physical performance variables and cut points predict falls and mortality differently in women and men, suggesting targeted sex-specific application of selected measures may improve outcome prediction in older adults.

Are social isolation, lack of social support or loneliness risk factors for cardiovascular disease in Australia and New Zealand? A systematic review and meta-analysis

BACKGROUND

An international systematic review concluded that individuals with poor social health (social isolation, lack of social support or loneliness) are 30% more likely to develop coronary heart disease (CHD) and stroke. Notably, the two included Australian papers reported no association between social health and CHD or stroke.

OBJECTIVE

We undertook a systematic review and meta-analysis to investigate the association between social isolation, lack of social support and loneliness and cardiovascular disease (CVD) incidence among people living in Australia and New Zealand.

METHODS

Four electronic databases were systematically searched for longitudinal studies published until June 2020. Two reviewers undertook title/abstract screen and one reviewer undertook full-text screen and data extraction. Quality was assessed using the Newcastle - Ottawa Quality Assessment Scale.

RESULTS

Of the 725 unique records retrieved, five papers met our inclusion criteria. These papers reported data from three Australian longitudinal datasets, with a total of 2137 CHD and 590 stroke events recorded over follow-up periods ranging from 3 to 16 years. Reports of two CHD and two stroke outcomes were suitable for meta-analysis. The included papers reported no association between social health and incidence of CVD in all fully adjusted models and most unadjusted models.

CONCLUSIONS

Our systematic review is inconclusive as it identified only a few studies, which relied heavily on self-reported CVD. Further studies using medical diagnosis of CVD, and assessing the potential influence of residential remoteness, are needed to better understand the relationship between social health and CVD incidence in Australia and New Zealand.

Patterns of discordance of physical functioning in older persons; different associations for apathy and depression? Results from the NESDO-study

OBJECTIVES

Discordance between self-reported functional limitations and performance-based physical functioning may have a negative impact in functional independence in older adults. We longitudinally examined baseline apathy- and depressive symptomatology as associates of discordance.

METHOD

469 participants from the multi-site cohort study NESDO were included. Self-reported functional limitations were assessed by two items derived from the WHO-Disability Assessment Schedule. Performance-based physical functioning included walking speed and handgrip-strength. Both measures were rescaled, with final sum-scores ranging from 0 to 6. Discordance-scores were computed by subtracting sum-scores on performance-based measures from self-reported functional limitations. Using latent growth curve analysis, we estimated individual trajectories of discordance at baseline, 2-and 6-years follow-up, consisting of the baseline discordance-score (intercept) and the yearly change of discordance-score (slope). We then estimated associations with apathy and depression indicators.

RESULTS

At baseline, persons (mean age 70.48 years, 65% female, 73% depressed) on average overestimated their daily functioning compared to performance tests (b = 0.77, p < 0.001). The average discordance-scores yearly increased by 0.15 (p < 0.001). Only in models adjusted for several demographic and clinical characteristics, depression severity was negatively associated with discordance-scores at baseline (b=-0.01, p = 0.02), while apathy was not (b=-0.02, p = 0.21). No associations with change over time were found.

CONCLUSION

In older persons, not indifference and diminished goal-directed activity, but negative emotions appear to underlie underestimation of one's physical capacity. Further research is needed to determine (1) to what extent targeting discordance results in actual preservation of physical functioning and (2) whether older persons with apathy and/or depression need different approaches for this purpose.

Does Late-Life Depression Counteract the Beneficial Effect of Physical Activity on Cognitive Decline? Results From the NESDO Study

OBJECTIVES

Depression both affects physical activity (PA) and cognition in older persons, yet its impact on the association between PA and cognitive decline is to be determined. We aimed to investigate the association between baseline PA and cognitive functioning over time, stratified for depression.

METHODS

We used data of the Netherlands Study of Depression in Older persons (NESDO), a multi-site cohort study with 6-years follow-up. Patients with complete data on PA and cognitive functioning at baseline were included, yielding 394 participants for the analyses of whom 297 were depressed and 97 non-depressed. PA (continuous) was measured with the International Physical Activity Questionnaire. Linear mixed models were used to determine differential effects of baseline PA on the rate of decline of 5 standardized outcomes of cognitive functioning over 6-year follow-up. For this purpose, we examined the significance of the interaction-term (PA*time) in both basic and adjusted models. We also assessed the association between time and cognitive functioning. All analyses were stratified for depression.

RESULTS

In both groups, no robust significant interactions of PA with time were found. Furthermore, only decline in working memory was significantly worse in the depressed compared to the non-depressed.

CONCLUSION

At older age, the impact of a more inactive lifestyle on cognitive decline was shown to be limited, irrespective of depression that appeared to worsen age-related decline of working memory only. As a higher PA-level at older age has a positive effect on a multitude of other health outcomes, PA should still be encouraged in this population.

Prediction of cardiovascular and all-cause mortality at 10 years in the hypertensive aged population

BACKGROUND

We have previously developed a score for predicting cardiovascular events in the intermediate term in an elderly hypertensive population. In this study, we aimed to extend this work to predict 10-year cardiovascular and all-cause mortality in the hypertensive aged population.

METHODS

Ten-year follow-up data of 5,378 hypertensive participants in the Second Australian National Blood Pressure study who were aged 65-84 years at baseline (1995-2001) and without prior cardiovascular events were analyzed. By using bootstrap resampling variable selection methods and comparing the Akaike and Bayesian information criterion and C-indices of the potential models, optimal and parsimonious multivariable Cox proportional hazards models were developed to predict 10-year cardiovascular and all-cause mortality. The models were validated using bootstrap validation method internally and using the Dubbo Study dataset externally.

RESULTS

The final model for cardiovascular mortality included detrimental (age, smoking, diabetes, waist-hip ratio, and disadvantaged socioeconomic status) and protective factors (female sex, alcohol consumption, and physical activity). The final model for all-cause mortality also included detrimental (age, smoking, random blood glucose, and disadvantaged socioeconomic status) and protective factors (female sex, alcohol consumption, body mass index, and statin use). Blood pressure did not appear in either model in this patient group. The C-statistics for internal validation were 0.707 (cardiovascular mortality) and 0.678 (all-cause mortality), and for external validation were 0.729 (cardiovascular mortality) and 0.772 (all-cause mortality).

CONCLUSIONS

These algorithms allow reliable estimation of 10-year risk of cardiovascular and all-cause mortality for hypertensive aged individuals.

Do statins cause diabetes?

A wealth of evidence has established that cholesterol-lowering statin drugs, widely used for the prevention of cardiovascular disease, do increase the risk of new-onset diabetes, possibly by impairing pancreatic beta cell function and decreasing peripheral insulin sensitivity. Groups at particular risk include the elderly, women, and Asians. The diabetogenic effect of statins appear directly related to statin dose and the degree of attained cholesterol lowering. Statins can cause hyperinsulinemia even in the absence of hyperglycemia and the potential mitogenic effects and implications of prolonged hyperinsulinemia are discussed. Suggestions are made as to how physicians might avert the hyperinsulinemic and diabetogenic effects of statin therapy in clinical practice, and modulate the detrimental effects of these drugs on exercise performance. Finally, long-term studies are needed to determine if the deleterious hyperinsulinemic and diabetogenic effects of statin therapy undermine the beneficial cardiovascular disease risk outcomes in various segments of the population.

Childbearing history and late-life mortality: the Dubbo study of Australian elderly

OBJECTIVE

to examine the association of parity with mortality in later life.

DESIGN

a longitudinal, community-based study.

SETTING

semi-rural town of Dubbo, NSW, Australia.

SUBJECTS

a total of 1,571 women and 1,233 men 60 years and older first examined in 1988-89.

OUTCOME MEASURES

all-cause and cause-specific mortality rates analysed over 16-year follow-up. Hazard ratios obtained from proportional hazards models employing conventional predictors, potential confounders and measure of parity.

RESULTS

increasing parity in women was weakly associated with overweight, diabetes and hypertension. All-cause mortality fell progressively with increasing parity in women (hazard ratio and 95% confidence intervals): childless, 1.00; 1 child, 1.03 (0.75-1.43); 2 children, 0.83 (0.61-1.11); 3 children, 0.80 (0.60-1.08); 4 children, 0.91 (0.66-1.25); 5 children, 0.70 (0.49-1.01); 6+ children, 0.60 (0.43-0.85) (trend for parity P<0.002). This result was similar whether or not hypertension, diabetes and overweight were included in multivariate models adjusting for social variables and other confounders. The reduction in all-cause mortality was accompanied by a parallel reduction in deaths from cancer and respiratory conditions, while coronary heart disease mortality increased 60-111% in all parous women.

CONCLUSION

there was increased all-cause mortality in later life in childless women, accompanied by reduced mortality as parity increased. Underlying mechanisms are unclear but findings may have public health importance.