The metabolic syndrome and cancer: Is the metabolic syndrome useful for predicting cancer risk above and beyond its individual components?

AIMS: The metabolic syndrome (MetS) is a risk factor for cancer. However, it is not known if the MetS confers a greater cancer risk than the sum of its individual components, which components drive the association, or if the MetS predicts future cancer risk. MATERIALS AND METHODS: We linked 20,648 participants from the Australian and New Zealand Diabetes and Cancer Collaboration with complete data on the MetS to national cancer registries and used Cox proportional hazards models to estimate associations of the MetS, the number of positive MetS components, and each of the five MetS components separately with the risk for overall, colorectal, prostate and breast cancer. Hazard ratios (HR) and 95% confidence intervals (95%CI) are reported. We assessed predictive ability of the MetS using Harrell's c-statistic. RESULTS: The MetS was inversely associated with prostate cancer (HR 0.85; 95% CI 0.72-0.99). We found no evidence of an association between the MetS overall, colorectal and breast cancers. For those with five positive MetS components the HR was 1.12 (1.02-1.48) and 2.07 (1.26-3.39) for overall, and colorectal cancer, respectively, compared with those with zero positive MetS components. Greater waist circumference (WC) (1.38; 1.13-1.70) and elevated blood pressure (1.29; 1.01-1.64) were associated with colorectal cancer. Elevated WC and triglycerides were (inversely) associated with prostate cancer. MetS models were only poor to moderate discriminators for all cancer outcomes. CONCLUSIONS: We show that the MetS is (inversely) associated with prostate cancer, but is not associated with overall, colorectal or breast cancer. Although, persons with five positive components of the MetS are at a 1.2 and 2.1 increased risk for overall and colorectal cancer, respectively, and these associations appear to be driven, largely, by elevated WC and BP. We also demonstrate that the MetS is only a moderate discriminator of cancer risk.

Gender differences in the trajectories of late-life depressive symptomology and probable depression in the years prior to death.

BACKGROUND: Gender differences in depression are well established. Whether these differences persist into late life and in the years preceding death is less clear. There is a suggestion that there is no increased likelihood of depression in late life, but that there is an increase in depressive symptomology, particularly with proximity to death. We compared trajectories of probable depression and depressive symptomology between men and women over age and distance-to-death metrics to determine whether reports of depressive symptoms are more strongly related to age or mortality. METHODS: Participants (N = 2,852) from the Dynamic Analyses to Optimise Ageing (DYNOPTA) project had a mean age of 75 years (SD = 5.68 years) at baseline and were observed for up to 16 years prior to death. Multi-level regression models estimated change in depressive symptomology and probable depression over two time metrics, increasing age, and distance-to-death. RESULTS: Increases in depressive symptomology were reported over increasing age and in the years approaching death. Only male participants reported increased probable depression in the years preceding death. Models that utilized distance-to-death metrics better represented changes in late-life depression, although any changes in depression appear to be accounted for by co-varying physical health status. CONCLUSIONS: As death approaches, there are increases in the levels of depressive symptomology even after controlling for socio-demographic and health covariates. In line with increases in suicide rates in late life, male participants were at greater risk of reporting increases in depressive symptomology.

Diet Liberalisation in Older Australians Decreases Frailty without Increasing the Risk of Developing Chronic Disease.

BACKGROUND: Successful ageing relies on the prevention of frailty and chronic disease, many of which have a strong link with diet. Despite evidence suggesting diet is important in the management of frailty, there is little evidence investigating the impact of a liberal diet on the prevention of frailty and development of chronic diseases in the elderly. OBJECTIVES: To determine the impact of a liberal diet on the development of frailty and whether this affects the incidence of obesity, diabetes, hypertension and hyperlipidaemia. DESIGN: Secondary data analysis of the Australian Longitudinal Study of Ageing, 1992 to 2000. SETTING: Random selection of older adults from the South Australian electoral roll. PARTICIPANTS: 1298 older Australians (629 women, 669 men), mean age 77 years. MEASUREMENTS: A validated food frequency questionnaire was used to measure the dietary exposure; liberal diet defined as: energy >10% estimated requirements; sodium >1600mg; total fat >35% energy; saturated fat >10%; refined sugar >10%; fibre <38g males and <28g females. Frailty was determined using the Fried phenotype in combination with Cesari's biological definition of frailty. Chronic disease outcomes were measured by medication usage and obesity defined as BMI >30kg/m². Binary logistic regression was performed using participants free of chronic disease at baseline to determine the impact of each dietary exposure independently, and combined, on the development of frailty and the incidence of chronic disease over the subsequent eight years. RESULTS: Incidence of frailty after 8 years of follow up was 14%. The incidence of diabetes after 8 years of follow up was 5.3%, hypertension 39%, hyperlipidaemia 15% and obesity 6%. A liberal energy intake adjusted for age and sex, significantly reduced the risk of developing frailty eight years post baseline (OR 0.48, 95% CI 0.30, 0.77). After adjustment for age, sex and body weight, a liberal saturated fat intake (>10% of energy) increased the risk of hyperlipidaemia (OR 2.11, 95% CI 1.27, 3.54). A liberal intake of sodium, total fat, refined sugar and fibre did not increase the risk of diabetes, hypertension, hyperlipidaemia or obesity. CONCLUSIONS: This study suggests that a liberal intake of energy may decrease the risk of developing frailty in the elderly without increasing the risk of developing obesity, diabetes, hypertension or hyperlipidaemia. Caution should remain however in the prescription of diets high in saturated fat as the link established with hyperlipidaemia in young adults appears to be consistent in the elderly. Further research is required to explore the optimal sources of energy for a liberalised diet and the effect of a liberalised diet on other diet related health conditions.

Health, economic, psychological and social impact of educating carers of patients with advanced pulmonary disease (protocol).

People with advanced pulmonary disease (APD), such as those with chronic obstructive pulmonary disease, have markedly impaired quality of life. Home Oxygen Therapy (HOT) itself is burdensome, although it often improves survival duration and quality of life in these patients. The exact burdens on informal caregivers of these patients are unknown. The central purpose of the pragmatic randomized controlled study described in this protocol is to determine the effectiveness of improving the skills and knowledge of carers of patients with APD who use HOT. Specifically we aimed to estimate the incremental impact of this carer intervention above usual care on health, economic, psychological and social domains for patient and carer dyads relative to the level of current burden. Eligible patients and their carers were recruited through three major hospitals, and randomized to an intervention or control group. The carers in the intervention group received two home-delivered education sessions based on the principles of academic detailing. Participants are currently being followed over 12 months. The primary outcome will be the proportion of patients surviving without a chronic obstructive pulmonary disease-related readmission / residential (non respite) care over 12 months. Carer secondary outcomes include perceived caregiver burden, level of expected and received social support, perceived level of mastery, self esteem, health related quality of life and disability, and ability to conduct domestic chores and household maintenance, social activities and provide service to others, and fatigue. Secondary patient outcomes include health related quality of life and disability, and current respiratory health status.

Comorbid chronic diseases, discordant impact on mortality in older people: a 14-year longitudinal population study.

OBJECTIVES: To determine the impact of comorbid chronic diseases on mortality in older people. DESIGN: Prospective cohort study (1992-2006). Associations between numbers of chronic diseases or mutually exclusive comorbid chronic diseases on mortality over 14 years, by Cox proportional hazards model adjusting for sociodemographic variables or Kaplan-Meier analyses, respectively. SETTING: Population based, Australia. PARTICIPANTS: 2087 randomly selected participants aged ≥65 years old, living in the community or institutions. MAIN RESULTS: Participants with 3-4 or ≥5 diseases had a 25% (95% CI 1.05 to 1.5, p=0.01) and 80% (95% CI 1.5 to 2.2, p<0.0001) increased risk of mortality, respectively, by comparison with no chronic disease, after adjusting for age, sex and residential status. When cardiovascular disease (CVD), mental health problem or diabetes were comorbid with arthritis, there was a trend towards increased survival (range 8.2-9.5 years) by comparison with CVD, mental health problem or diabetes alone (survival 5.8-6.9 years). This increase in survival with arthritis as a comorbidity was negated when CVD and mental health problems or CVD and diabetes were present in disease combinations together. CONCLUSION: Older people with ≥3 chronic diseases have increased risk of mortality, but discordant effects on survival depend on specific disease combinations. These results raise the hypothesis that patients who have an increased likelihood of opportunity for care from their physician are more likely to have comorbid diseases detected and managed.

A syndromal analysis of neuropsychological outcome following coronary artery bypass graft surgery.

BACKGROUND: Studies of neuropsychological outcome following coronary artery bypass graft surgery (CABG) have traditionally dichotomised patients as "impaired" or "unimpaired". This conceals the potential heterogeneity of deficits due to different mechanisms and sites of brain injury. OBJECTIVES: To explore neuropsychological outcome following CABG and determine to what extent it conforms to prototypic cortical and/or subcortical neurobehavioral syndromes and whether different intraoperative physiologic measures are associated with different subtypes of neuropsychological outcome. METHODS: Neuropsychological tests were administered to 85 patients before and after elective CABG and to 50 matched normal control subjects. Pre- to postoperative change scores were computed using standardised regression based norms. Change scores on selected memory measures were subjected to cluster analysis to identify qualitatively distinct subtypes of memory outcome. Emergent clusters were compared on non-memory measures, intraoperative physiologic measures, and demographic variables. RESULTS: Three subtypes of memory outcome were identified: memory spared (48% of patients), retrieval deficit (35%), and encoding/storage deficit (17%). Contrary to expectation, the subgroups were indistinguishable on measures of confrontation naming and manual dexterity and on intraoperative cardiac surgical physiologic measures and demographic variables. The encoding/storage deficit subgroup exhibited executive dysfunction. CONCLUSIONS: Heterogeneous profiles of neuropsychological dysfunction were found following CABG although they did not tightly conform to prototypic cortical and subcortical neurobehavioral syndromes. This challenges the value and appropriateness of the common practice of collapsing individual test scores to arrive at a single figure to define "impairment". Whether different subtypes of neuropsychological outcome are caused by different pathophysiologic mechanisms remains unknown.

Two-year decline in vision but not hearing is associated with memory decline in very old adults in a population-based sample.

BACKGROUND: Recent cross-sectional research in cognitive aging has demonstrated a robust association between visual acuity, auditory thresholds and cognitive performance in old age. However, the nature of the association is still unclear, particularly with respect to whether sensory and cognitive function are causally related. OBJECTIVE: This study aimed to determine whether marked declines in performance on screening measures of either visual acuity or auditory thresholds have an effect on cognitive decline over 2 years. METHODS: The sample from the Australian Longitudinal Study of Ageing (n = 2,087) were assessed in 1992 and 1994 on measures of sensory and cognitive function as part of a larger clinical assessment. A quasi-experimental design involving comparison of extreme groups using repeated measures MANCOVA with age as a covariate was used. RESULTS: Group performance on measures of hearing, memory, verbal ability and processing speed declined significantly. Decline in visual acuity had a significant effect on memory decline, but not on decline in verbal ability or processing speed. Decline in hearing was not associated with decline in any cognitive domain. CONCLUSION: The common association between visual acuity, auditory thresholds and cognitive function observed in cross-sectional studies appears to be disassociated in longitudinal studies.

Demographic, health, cognitive, and sensory variables as predictors of mortality in very old adults.

Cognitive and sensorimotor predictors of mortality were examined in the Australian Longitudinal Study of Ageing, controlling for demographic and health variables. A stratified random sample of 1,947 males and females aged 70 and older were interviewed, and 1,500 were assessed on measures of health, memory. verbal ability, processing speed, vision, hearing, and grip strength in 1992 and 1994. Analyses of incident rate ratios for mortality over 4- and 6-year periods were conducted using Cox hierarchical regression analyses. Results showed that poor performance on nearly all cognitive variables was associated with mortality, but many of these effects were explained by measures of self-rated health and disease. Significant decline in hearing and cognitive performance also predicted mortality as did incomplete data at Wave 1. Results suggest that poor cognitive performance and cognitive decline in very old adults reflect both biological aging and disease processes.

A reevaluation of the common factor theory of shared variance among age, sensory function, and cognitive function in older adults.

The common cause hypothesis of the relationship among age, sensory measures, and cognitive measures in very old adults was reevaluated. Both sensory function and processing speed were evaluated as mediators of the relationship between age and cognitive function. Cognitive function was a latent variable that comprised 3 factors including memory, speed, and verbal ability. The sample was population based and comprised very old adults (n = 894; mean age = 77.7, SD = 5.6 years) from the Australian Longitudinal Study of Ageing. The results showed that there was common variance in the cognitive factor shared by age, speed, vision, and hearing but that specific effects of age on cognition remained. Furthermore, speed did not fully mediate the effect of age or sensory function on cognition. Some age differences in cognitive performance are not explained by the same processes that explain age differences in sensory function and processing speed.

Adult age differences in self-ordered pointing task performance: contributions from working memory, executive function and speed of information processing.

This study investigated adult age differences in, and predictors of, the performance of a test of executive function, the Self-Ordered Pointing Task (SOPT; Petrides & Milner, 1982). Performance on the SOPT is thought to rely on high level working memory processes, therefore, measures reflecting the common operationalization of working memory, along with measures of executive function and speed of information processing, were investigated as predictors of SOPT performance. Younger (aged 17-48 years) and older (aged 65-88 years) adults completed a 16-item, 3-trial, modified version of Shimamura and Jurica's (1994) version of the SOPT, and tests assessing working memory, executive function and speed. Results showed that younger adults made fewer errors on the SOPT. There was no age difference in the frequency of use of a clustering strategy. Contrary to expectations, working memory was not a good predictor of individual or age differences in SOPT performance. Instead, speed of processing, and to a lesser extent, measures of perseverations, made larger unique and overlapping contributions to the variance. The SOPT and its association, or dissociation, with other measures of working memory may be useful for research into the nature of working memory and executive function and the theoretical links between them.

Measurement of subjective quality of life of elders.

There are two aims in this article, to define subjective quality of life and to suggest a way to standardize its measurement to enable comparisons to be made across studies. One of the unresolved issues in gerontological research has concerned the definition and measurement of quality of life (Lawton, 1991). This article focuses on subjective well-being, one of the four components proposed by Lawton (1991). There seems to be a growing consensus that most scales of well-being have at least two concepts in common, positive and negative affect. To test this hypothesis, two well-being scales, the Philadelphia Geriatric Center Morale Scale (Lawton, 1975) and the Center for Epidemiological Studies-Depression Scale (Radloff, 1977), were subjected to confirmatory factor analyses, using data on 1717 participants in the Australian Longitudinal Study of Ageing aged between 70 and 103 years. Each scale was shown to contain factors of positive and negative affect. The article concludes with a suggestion that the measurement of quality of life in elders should include, at a minimum, scales of positive and negative affect as well as other measures relevant to the aspect of quality of life under consideration.

Measures of fluency as predictors of incidental memory among older adults.

This study investigated fluency performance as a mediator of age-related declines in incidental memory performance as both are thought to rely on strategic retrieval processes. A large sample of community dwelling older adults completed a battery of tests assessing fluency, verbal knowledge, speed of information processing, and incidental recall. Fluency measures included initial and excluded letter fluency and the Uses for Objects Test, and they were assumed to reflect increasing reliance on strategic retrieval search. Speed emerged as the best mediator of age-related variance in incidental recall, and Uses for Objects Test performance added to the variance after controlling for verbal knowledge and speed. The results suggest that age-related decline in incidental recall is largely due to speed and the strategic search of memory.

Measurement of executive function: considerations for detecting adult age differences.

This review considers the validity and suitability of neuropsychological and other tests of executive function for the detection of adult age differences in executive function. Executive function is typically assessed using tests which have been found to be sensitive to frontal lobe dysfunction because theory links executive function with the frontal lobes. However, any age-related decline in executive function is expected to be mild, or sub-clinical, compared to the deficits shown among those with frontal lesions. Therefore, in order to detect the type of mild executive dysfunction expected among older adults we need to employ tests sensitive enough to detect any age-related deficit, yet which are not too stressful or tiring for older adults to perform. This review discusses some commonly used neuropsychological tests of executive function as well as tests devised to assess theoretical aspects of executive function. Indications are given throughout as to which tests appear to be most suitable for detecting age differences in executive function.

Challenges to understanding age-related memory loss in late adulthood: an introduction.

BACKGROUND: In the first 1999 issue of Gerontology several current hypotheses of age-related memory loss were canvassed. OBJECTIVE: In hopes of fostering debate and further consideration of factors implicated in memory loss in late adulthood, commentaries were sought from a number of prominent cognitive ageing researchers on this review. METHODS: Four commentaries were received and are briefly distilled in this preamble to them. RESULTS: The papers elaborate on several themes raised in the original review, articulate assumptions implicit in the review, question the techniques used to assess mediational hypotheses, and suggest factors omitted from the review that need also to be considered. CONCLUSION: Despite an extensive literature on memory ageing, we are still a long way from understanding the mechanisms responsible for it. While considerable progress has already been made, over-reliance on between-person analyses, ambiguity in underlying constructs, and omission from consideration of key situation-specific characteristics of a memory episode may all contribute to a less than definitive understanding of memory ageing.

Toward understanding age-related memory loss in late adulthood.

BACKGROUND: While laboratory tests indicate that older adults typically perform more poorly than do younger adults on many types of memory tasks, the question arises as to whether, or to what extent, it is valid to attribute these differences to ageing per se or to some variable or class of variables that intervene between age and remembering. OBJECTIVE: The purpose of this review is to present three current views that might explain the relationship between age and remembering. They can be construed as variants on resource theories and include: the processing speed hypothesis, the executive function hypothesis, and the common cause hypothesis. METHODS: The review samples results pertinent to these hypotheses that derive from behavioural research. Studies involving various imaging techniques were considered beyond the scope of the review. RESULTS: The balance of research strongly implicates reductions in the speed of information processing as a fundamental contributor to normal age-related memory loss. Nonetheless there are circumstances where other mechanisms, such as working memory, executive function, and sensory processes, are important. CONCLUSION: Despite the phenomenological and empirical reality of age-related memory loss and the breadth of attempts to explain it, much work remains to be done to understand why it occurs. Contemporary debates about the nature and means of identifying shared and unique effects promise to shape future directions for research on memory aging.

The role of self-perceived usefulness and competence in the self-esteem of elderly adults: confirmatory factor analyses of the Bachman revision of Rosenberg's Self-Esteem Scale.

This article reports on a confirmatory analytic study of the Bachman Revision (1970) of Rosenberg's Self-Esteem Scale (1965) that was used in the Australian Longitudinal Study of Ageing (ALSA). Participants comprised 1,087 elderly people aged between 70 and 103 years (mean 77 years). Five competing factor models were tested with LISREL8. The best-fitting model was a nested one, with a General Self-Esteem second-order factor and two first-order factors, Positive Self-regard and Usefulness/Competence. This model was validated with data from a later wave of ALSA. Usefulness and competence have received little attention in the gerontological literature to date. Preliminary results indicate that usefulness/competence may be an important predictor of well-being. Further work is required on the relationships among usefulness, competence, self-esteem, and well-being in elderly people.