PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 16257034

Decrease in the relative heterogeneity of health with age: a cross-national comparison.

Arnold Mitnitski·Kenneth Rockwood
View original source ↗Export metadata ↓

Abstract

Using data from seven studies from Canada, Australia and the United States we were able to evaluate the heterogeneity of health status for 34,095 people aged 60 years and older. We found that relative heterogeneity (measured by the coefficient of variation) decreased with age. The coefficient of variation also decreased as a function of deficit accumulation (i.e. was lower when people demonstrated more deficits) displaying a power-law relationship. The exponent was close to 0.5, and therefore belongs to the dynamic universality class, which is typical for complex dynamical networks. We interpret this as showing that decline in relative heterogeneity is a robust finding, and represents, at the group level, increased vulnerability amongst elderly people.

Explore related subjects

Age DistributionAgedAged, 80 and overAgingCanadaHealth StatusHumansMiddle AgedComparative StudyJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Arnold Mitnitski, Kenneth Rockwood. 2005-10-27. Decrease in the relative heterogeneity of health with age: a cross-national comparison.. https://doi.org/10.1016/j.mad.2005.09.007

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

A resistance gene in disguise for schizophrenia?

We examined the hypothesis that -485 T, a novel polymorphism in the promoter region of the neuropeptide Y gene which was shown to be associated with schizophrenia in our previous paper, confers susceptibility to the disease. For a case-control association study, 331 unrelated Japanese schizophrenics (S(1): milder cases in the previous study, n = 212; and S(2): additional severer cases, n = 119) and 199 unrelated normal controls were recruited. Contribution of -485 T to the risk and the severity of the illness was examined by (1) comparing the risk in each genotype in the general population, (2) testing correlations between the gene-dose of -485 T, and the severity of chronic outcome in S(2) assessed with the Positive and Negative Symptom Scale, and (3) comparing the distribution of age at onset in S(1) + S(2) among the three genotypes. -485 T was significantly associated with schizophrenia in S(1) + S(2). Significant negative correlations were observed between the gene-dose and the symptom assessment scores in all items. The homozygote of -485 T showed a second peak frequency in the late-onset group both in males and females, while the homozygote of the alternative allele showed a single peak in the early-onset group. The higher risk of schizophrenia in the heterozygote than in the homozygote of -485 T in the general population did not support the possibility of linkage disequilibrium with a susceptibility gene. -485 T most likely confers resistance but not susceptibility to schizophrenia. An interaction between a nuclear resistance gene and a presumptive pathogenic gene in the mitochondrial DNA was suggested.

Age Distribution↗
PubMed2007

Biologically relevant sex differences for fitness-related parameters in active octogenarians.

The number of elderly people is growing in western populations, but only few maximal performance data exist for people >75 years, in particular for European octogenarians. This study was performed to characterize maximal performance of 55 independently living subjects (32 women, 81.1 +/- 3.4 years; 23 men, 81.7 +/- 2.9 years) with a focus on sex differences. Maximal performance was determined in a ramp test to exhaustion on a bicycle ergometer with ergospirometry, electrocardiogram and blood lactate measurements. Maximal isometric extension strength of the legs (MEL) was measured on a force platform in a seated position. Body composition was quantified by X-ray absorptiometry. In >25% of the subjects, serious cardiac abnormalities were detected during the ramp test with men more frequently being affected than women. Maximal oxygen consumption and power output were 18.2 +/- 3.2 versus 25.9 +/- 5.9 ml min(-1) kg(-1) and 66 +/- 12 versus 138 +/- 40 W for women versus men, with a significant sex difference for both parameters. Men outperformed women for MEL with 19.0 +/- 3.8 versus 13.6 +/- 3.3 N kg(-1). Concomitantly, we found a higher proportion of whole body fat in women (32.1 +/- 6.2%) compared to men (20.5 +/- 4.4%). Our study extends previously available maximal performance data for endurance and strength to independently living European octogenarians. As all sex-related differences were still apparent after normalization to lean body mass, it is concluded that it is essential to differentiate between female and male subjects when considering maximal performance parameters in the oldest segment of our population.

Age Distribution↗
PubMed2007

The effect of gender, age, and geographical location on the incidence and prevalence of renal replacement therapy in Wales.

BACKGROUND: This study used a cross sectional survey to examine the effect of gender, age, and geographical location on the population prevalence of renal replacement therapy (RRT) provision in Wales. METHODS: Physicians in renal centres in Wales and in adjacent areas of England were asked to undertake a census of patients on renal replacement therapy on 30 June 2004 using an agreed protocol. Data were collated and analysed in anonymous form. RESULTS: 2434 patients were on RRT in Wales at the census date. Median age of patients on RRT was 56 years, peritoneal dialysis 58 years, haemodialysis 66 years and transplantation 50 years. The three treatment modalities had significantly different age-specific peak prevalence rates and distributions. RRT age-specific prevalence rates peaked at around 70 years (1790 pmp), transplantation at around 60 years (924 pmp), haemodialysis at around 80 years (1080 pmp) and peritoneal dialysis did not have a clear peak prevalence rate. Age-specific incidence of RRT peaked at a rate of 488 pmp at 79 years, as did incidence rates for haemodialysis, which peaked at the same age. Age had less effect on the initiation of peritoneal dialysis, which had a broad plateau between the early fifties and late seventies. Kidney transplantation rates were highest in the early fifties but were markedly absent in old age. CONCLUSION: Differences in the provision of RRT are evident, particularly in the very elderly, where the gender difference for haemodialysis is particularly marked. The study illustrates that grouping patients over 75 years into a single age-band may mask significant diversity within this age group. Significant numbers of very elderly patients who are currently not receiving RRT may wish to receive RRT as the elderly population increases, and as technology improves survival and quality of life on RRT. The study suggests that if technologies that are more effective were developed, and which had a lower impact on quality of life, there might be up to a 17% increase in demand for RRT in those aged over 75 years; around 90% of this increased demand would be for haemodialysis.

Age Distribution↗