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[1] Thoughts
What this series is about ...Health and Ageing News offers a systematic approach to quality of life. Our aim is to bring to you state-of-the-art information on government policy reforms, research findings, book reviews, news, and articles that highlight the understanding of a successful ageing process. The articles will cover a range of critical topics including biology, behavioural and social sciences, epidemiology, clinical practice and health, food and nutrition, and social research, planning and practice. Organised into sections addressing innovative developments in these fields, we hope to reach a broad audience and to facilitate a continuum of self-care. Each contribution will address the applied implications of health care research and offer practical guidance to readers dealing with these issues in their own lives and in the care of their families. As a whole, major advance in information technology has transformed health communication and health literacy. This series represents the highest levels of current scholarship in health and ageing, and a strong foundation for future research. |
The genetic basis of human ageing
The evolutionary theory of ageing provides valuable insight into the mechanisms underlying the complex cellular and molecular changes contributing to senescence. It also helps to clarify how the genome shapes the ageing process. This information helps to further our understanding and study of the complex genetic factors influencing longevity and age-associated diseases.
Since the first cell culture was set at the beginning of the twentieth century it was believed that all cultured cells, if provided with the proper conditions, would replicate indefinitely. Sixty years later scientists overthrew this dogma by finding that normal cells have a finite capacity to replicate and that only abnormal or cancer cell populations can replicate indefinitely. Interpretation of these findings led to understanding the ageing process. If, as had been previously thought, normal cells can replicate indefinitely, then age changes could not have an intracellular origin.
On the contrary, in 2003 Hayflick demonstrated that age changes do have an intracellular origin. Other changes that were subsequently found to precede the loss of replication capacity of the cell were interpreted to be age changes and the finitude of replication to be an expression of longevity determination (Hayflick, 2003). Subsequent findings of other researchers determined the molecular mechanism that governs the finitude of normal cell replication capacity and how immortal cancer cells escape this inevitability. Thus, key events in the understanding of ageing, longevity determination and cancer were revealed.
Compelling research evidence confirms that DNA damage is a common mediator for both replicative senescence (triggered by telomere shortening and premature cellular senescence) induced by various stressors such as oncogenic stress and oxidative stress.
Research also suggests that DNA damage accumulates with age and that this may be due to an increase in production of reactive oxygen species (ROS) and a decline in DNA repair capacity with age. Mutation or disrupted expression of genes that increase DNA damage often results in premature ageing. In contrast, interventions that enhance resistance to oxidative stress and attenuate DNA damage contribute to longevity. This evidence suggests that genomic instability plays a causative role in the ageing process. However, other conflicting findings exist which indicate that ROS production and oxidative damage levels of macromolecules (including DNA) do not always correlate with lifespan in model animals (Chen, Hales & Ozanne, 2007).
In this connection, Martin et al (2007) published a review of the three approaches to the genetic analysis of the biology and pathobiology of human ageing. The first--and so far the best-developed--is the search for the biochemical genetic basis of varying susceptibilities to major geriatric disorders. These include a range of progeroid syndromes. Collectively, they tell us much about the genetics of life span. Given that the major risk factor for virtually all geriatric disorders is biological ageing, they may also serve as markers for the study of intrinsic biological ageing.
The second approach seeks to identify allelic contributions to exceptionally long life spans. While linkage to a locus on Chromosome 4 has not been confirmed, association studies have revealed a number of significant polymorphisms that impact upon late-life diseases and life span.
The third approach remains theoretical. It would require longitudinal studies of large numbers of middle-aged sib-pairs who are extremely discordant or concordant for their rates of decline in various physiological functions.
The genetic basis of human longevity
There is clear heritability of human longevity. Longevity varies between and within species. Longevity determination is governed by the excess of physiological capacity reached at the time of sexual maturation through natural selection and it is only indirectly determined by specific genes (Kirkwood, 2008).
The existence of species-specific limit to human life-span and its partial heritability have indicated the existence of genetic factors that influence the ageing process. Ageing is a process that begins after puberty and results from increasing random systemic molecular disorder. This disorder has multiple causes, including damage by reactive oxygen species, known as oxygen free radicals, but generally results from the gradual loss of the energy necessary to maintain molecular structure and function. On the other hand, longevity determination (the rate of ageing) is not a random process. A species' life span has been determined over time by natural selection. Natural selection favours animals that have greater capacity for survival to achieve reproductive success and physiological reserve to overcome damage by external forces like disease, accidents or environmental extremes. One important interpretation of the research finding that a normal cell is limited in its ability to divide is that this limit is a manifestation of that cell's potential for longevity. This finding reflects longevity determination in the animal itself (Schachter, Cohen & Kirkwood, 1993).
Another interpretation is that as cells approach senescence, their many losses in function increase their vulnerability to diseases or pathologies that are so common in old age.
Some data from the study of humans points to a theoretical role for cellular senescence in the diseases of ageing. For example, research on the Werner syndrome (inherited disease of premature ageing) suggests that cellular senescence causes a range of cellular destruction that result in age-related diseases. In this connection, comparisons of cells in culture from younger persons with Werner syndrome and older persons show that both groups of cells have a limited ability to reproduce further. Both cell types also go on to form abnormal extra-cellular matrixes that are the framework to hold cells together as tissues. This observation indicates that a small number of senescent cells can affect neighbouring cells and tissues and perhaps contribute to age-related declines in the function of those cells and tissues (Agrelo, 2007).
In a letter to the editor of The Lancet, a group of researchers reported the results of their study of individuals with known atherosclerosis, a component of heart disease causing hardening of the arteries. Ten patients with severe heart disease were compared with twenty who were healthy. The study found that the telomeres of the people with heart disease were shorter than those without; in fact, the heart disease patients had telomeres that resembled those of persons at least eight years older. This pilot study information is intriguing and further investigation is continuing (Samani, Boultby, Butler et al, 2001).
Ageing is also related to progressive cognitive decline. However, as with arterial ageing, severe cognitive decline does not appear to be an inevitable process. Alzheimer Disease (AD), one of the most relevant and frequent causes of cognitive decline, is genetically determined to only a small extent, and modifiable environmental and lifestyle factors (smoking, nutrition, physical inactivity and low social activity) are thought to play a key role in its development (Briones, 2006). Further research is continuing to identify the factors linked with cognitive decline and to clarify ways in which the environment and genes interact to foment neurological deterioration.
Despite steady improvements in health and quality of life, the maximum life span for humans throughout recorded history remains about 115-120 calendar years. The oldest documented person on record is Jeanne Calment, a French woman who lived for 122 years and 164 days. Although such an age is still uncommon, the maximum life-span of humans has continued to increase because world records for longevity can only move in one direction, higher. However, Olshansky et al (2002) point out that despite this trend it is almost certainly true that, at least since recorded history, people could have lived as long as those alive today if similar technologies, lifestyles, and population sizes had been present. It is not people that have changed, it is the protected environments in which we live and the advances made in biomedical sciences and other human institutions that have permitted more people to attain, or more closely approach, their life-span potential (Olshansky, Hayflick & Carnes 2002).
It may be that the reduction of infant mortality has accounted for most of this increased average longevity. However, international data indicates that since the 1960s mortality rates among those over 80 years in most developed countries has decreased by about 1.5% per year, and that the increase in longevity has not been accompanied by an increase in disease-free life expectancy. Some research advances, in this respect, indicate that calorie restriction with appropriate nutrition or other interventions are said to have slowed the ageing process . The caloric restriction has not been proven to extend the maximum human life span although recent results in ongoing primate studies are promising. Nevertheless, the differences in life span between species demonstrate the role of genetics in determining maximum life span (Ingram, Roth, Lane et al, 2006).
If health-related quality of life--and not longevity--is the key goal for health promotion, then it is captured only partly by the existing mortality and morbidity index. As such, scientists now urge institutions and health care providers to begin collecting quality-of-life data on the populations they serve. Adding life to years, not years to life, is the current agenda for productive and successful ageing. Therefore, policies and programs on ageing are increasingly focused on identifying ways to improve quality of life and health status rather than just extending life span.
So, what defines quality of life for older people?In the Healthy People 2000 report, the chief goal of health promotion was to increase the span of healthy life. The focus was on mortality and morbidity data and symptom checklists as the principal measures of ill health (Healthy People 2000).
In contrast, in the Healthy People 2010 report the emphasis is on quality of life and overall well-being. Helping people to increase life expectancy and improve their quality of life is the primary goal of the new report (Healthy People 2010). In this report, the authors of this special issue (including the journals of Gerontology; Biological Sciences; and Medical Sciences) are united in the belief that optimal nutrition and physical activity make a significant contribution to the overall quality of life at any age and especially for older adults. The key research challenge now lies in deciding which aspects of improved fitness, nutrition, and diet contribute the most to quality-of-life measures.
A comprehensive review of research on exercise, nutrition, diet, and health in elderly adults has largely addressed biomedical outcomes, pointing to substantial benefits in physical functioning, remission of disease symptoms, and improved health. This special issue goes a step further in assessing the effect of improved nutrition and physical activity on the global quality of life and its four principal domains. Although links between diet and exercise and chronic disease risks have been well documented, more needs to be known about motivations for behavioural change and perceived benefits as assessed using quality-of-life measures (Drewnowski & Evans, 2001).
No single segment of our society can benefit more from regularly performed exercise and improved diet than elderly adults. These important articles provide a link between diet and exercise and quality-of-life issues, as outlined in the Healthy People 2010 report.
Ageing is accompanied by a variety of physiological, psychological, economic and social changes that may adversely affect nutritional status. Older people have a higher prevalence of chronic disease, take multiple medications and supplements, and tend to be sedentary. Higher prevalence of obesity is difficult to reconcile with sharply lowered energy intakes. While basal metabolic rate does decline with age, lack of physical activity among older people is the more likely answer (Drewnowski & Warren-Mears, 2001).
The Healthy People 2010 objectives use quality of life as a national health standard. Whereas health related quality of life (HRQOL) measures assess physical and mental health and their determinants, global quality of life measures focus on life satisfaction. Optimal nutrition promotes both functional health status and mental well-being. Dietary diversity and variety promotes enjoyment and satisfaction with the diet. Regular physical activity promotes strength and endurance, helps to maintain appropriate body weight, and contributes to independent physical functioning. Improving health-related quality of life is a key element in promoting the health and well-being of older adults (Amarantos, Martinez & Dwyer, 2001).
Measuring Quality of Life (QoL) requires a multidimensional parameter evaluation, using both intrapersonal and social-normative criteria, and taking account of an individual in time (past, current and anticipated). Great differences exist at inter- and intra-persona levels in the assessment of QoL. Influential variables on QoL include marital status, income, health status and social environment. Designing and implementing interventions to positively modify some of these factors may guarantee a better quality of life for older people by, for example, facilitating social participation, supporting networks, employing older workers and taking strong actions to eradicate ageism (Nakasato & Carnes, 2006).
Furthermore, QoL measures act as a predictor per se of age-related disorders--e.g. cardiovascular disease (CVD), Alzheimer Disease (AD)--but, again, further research in this area may help to clarify potential mechanisms involved in healthy ageing to discern the effect of QoL in longevity, morbidity and vice versa (Bowling & Iliffe, 2006).
In the meantime, public health practice continues its research into environmental and social determinants of health and disease. In this connection, the SAX Institute (an independent research centre established in 2002, comprising members of the Universities of Newcastle, New South Wales and Sydney, and NSW Department of Health) has initiated a 45 and up research study (Understanding Ageing: the 45 and up) with a view to improve health and increase the quality and performance of health services and programs in New South Wales (The 45 and up, 2008) .
This NSW longitudinal study, will track participants of age 45 and over with five-yearly questionnaires until they die, to explore how every aspect of their daily lives, from whom they meet to what they eat, has an impact upon their health. At present, there are 60,000 participants and another 100,000 people are expected to receive the questionnaire in the mail through Medicare. The research aims to survey 250,000 people (10 per cent of the eligible NSW population) and the study will have access to their medical records and, over time, biological samples.
The aim of the 45 and up research study is to create a databank of information on healthy ageing, an area in need of reliable evidence to inform government on policy services and intervention strategies for the coming decades. The data collected will be linked to State databases on such things as hospital admissions and deaths. It will also underpin further research on social and economic determinants of healthy ageing, including: income, education and retirement; the effects of being overweight, obesity and exercise; risk factors and early detection and management of cancer, cardiovascular disease and mental health problems; and the use of health services.
The advances brought about by scientific research and changes in the perceptions about genomic variations within populations are now targeted for increased health promotion messages and disease prevention programs specifically for at-risk genomic profiles such as susceptible individuals and families or subgroups of populations. As the controversial discourse in science and health politics shows, the integration of genomics into public health research, policy and practice is one of the major challenges that our health-care system is facing (Reid & Emery, 2006) and (Brand, Helmut & Tobias Schulte in den Baumen, 2008).
Since completion of the Human Genome Project in 2003 community expectations continue to rise on the information (and application) of human genome discoveries in disease prevention, especially in the area of common chronic diseases. Almost daily we are confronted with stories of scientific discoveries of human genetic variants that are suggested to affect our risks for one or more of the major common chronic diseases. Yet the immediate significance of most of these discoveries often remains vague; and scientific and personalised management of chronic disease prevention and drug treatment remain to be fully realized (Khoury, Burke & Thomson, 2000).
Bibliography
Bowling A & Iliffe S, 2006.Which model of successful ageing should be used? Baseline f ind ings from a British longitudinal survey of ageing, Age and Ageing 2006 35(6):607-614, http://ageing.oxfordjournals.org
Brand A, Helmut B and Tobias Schulte in den Baumen, 2008. The impact of genetics and genomics on public health, European Journal of Human Genetics ; 16: 5 -13, http://www.nature.com
Briones TL Environment, physical activity, and neurogenesis: implications for prevention and treatment of Alzheimer's disease. Curr Alzheimer Res. 2006; 3:49–54. [PubMed]
Calment Jeanne, http://en.wikipedia.org/wiki/Jeanne_Calment
Chen CH, Hales CN & Ozanne SE, 2007. DNA damage, cellular senescence and organismal ageing: causal or correlative? Nucleic Acids Research, 2007, Vol. 35, No. 22, pp 7417-7428, http://nar.oxfordjournals.org
Donald K Ingram, George S Roth, Mark A Lane, et al, 2006. The potential for dietary restriction to increase longevity in humans: extrapolation from monkey studies. Biogerontology, Volume 7:3; June 2006, Springer Netherlands, http://www.springerlink.com
Drewnowski A, Evans WJ, 2001. Nutrition, physical activity, and quality of life in older adults. Gerontol A Biol Sci Med Sci. 2001 Oct; 56 Spec No 2:89-94. http://www.ncbi.nlm.nih.gov/pubmed
Harman D, 2006. Alzheimer's disease pathogenesis: role of ageing. Ann N Y Acad Sci . 2006; 1067; 454-460.
Hayflick L, 2003. Living forever and dying in the attempt. Experimental Gerontology, Volume 38, No 11, November 2003, pp. 1231-1241(11), Elsevier
Khoury MJ, Burke W & Thomson E, 2000 (eds) Genetics and public health in the 21st century: using genetic information to improve health and prevent disease. New York: Oxford University Press; 2000.
Kirkwood TB 2008. Understanding ageing from an evolutionary perspective, Journal of Internal Medicine, Volume 263, Number 2, February 2008, pp. 117-127(11), Blackwell Publishing, http://auscathuniaus.library.ingentaconnect.com
Martin GM, Bergman A, Barzilai N, 2007. Genetic determinants of human health span and life span: progress and new opportunities, PLoS Genet 3(7): e125, Public Library of Science, http://genetics.plosjournals.org
Nakasato YR & Carnes BA, 2006. Health promotion in older adults: Promoting successful ageing in primary care settings, Geriatrics, 2006, Vol.61, No 4, pp.27-31.
Reid G, Emery J 2006. Chronic disease prevention in general practice--Applying the family history. Australian Family Physician. 2006 Nov; 35(11):879-82, 884-5.
Schachter F, Cohen D & Kirkwood TB, 1993. Prospects for the genetics of human longevity. Hum Genet . 1993 Jul; 91(6):519-26, Public Library of Science, http://www.ncbi.nlm.nih.gov/pubmed
The SAX Institute, 45 and Up, http://www.45andup.org.au
US Office of Disease Prevention and Health Promotion, Healthy People 2000, http://www.crisny.org/health/us/health7.html
US Office of Disease Prevention and Health Promotion, Healthy People 2010, http://www.faqs.org/nutrition/Hea-Irr/Healthy-People-2010-Report.html
[2] Community Update
Book Review
1. Biology of life span: A quantitative approach
By Leonid A Gavrilov and Natalia S Gavrilova (eds) VP Skulachev, Harwood Academic Publishers, 1991
This work, which is translated from the original Russian, summarises the significant facts and theories concerning the finite life span. It takes an interdisciplinary approach based on the quantitative analysis of survival regularities both in human populations and in animal models. Questions considered include whether life span is programmed or not, whether there is an absolute upper limit to the duration of life, the relative role of social and biological factors, why women live longer than men, and prospects for, and ways of prolonging, the life span.
Professor Nathan Keyfitz of the International Institute for Applied Systems Analysis, Laxenburg, Austria, in his review says Gavrilov makes the best attempt I know of to distinguish how long people could live from how long they actually live -- one of the more difficult tasks for both biology and statistics... Gavrilov's scholarship is impressive. Keyfitz, Mathematical Population Studies, 1991, Vol 3, No 2, p.161.
Research ReportsThe Australian Institute of Health and Welfare (AIHW) has released two new dental reports:
1. Water fluoridation and children's dental health: the child dental health survey, Australia 2002This publication by the AIHW Dental Statistics and Research Unit presents the results of The Child Dental Health Survey, Australia 2002 and examines the differences in oral health of children residing in areas of different concentration of fluoride in the public water supply. The findings demonstrate that decay experience differs across areas of different water fluoride concentration, with children residing in areas with water fluoridation having better oral health than children residing in areas with no or negligible fluoride concentrations in the public water. The publication also reveals the state of oral health in Australia's school-age children, including age-specific and age-standardised measures of dental decay experience within each state and territory, and national estimates of these measures for 2002.
Australian children experience low levels of dental decay compared to their international counterparts. However, a minority of children still experience extensive decay and carry most of the burden of this disease. Information regarding children's oral health can serve as a guide for policy development in order to further improve the oral health of, and service delivery to, Australian children.
2. Geographic distribution of the Australian dental labour force, 2003
Geographic distribution of the Australian dental labour force 2003 presents results from the 2003 National Dental Labourforce Data Collection. The collection includes all dentists, dental therapists, dental hygienists and dental prosthetists across Australia. This publication presents the overall numbers and the practice status of the dental labour-force in each State and Territory, across geographic remoteness regions and nationally. Other statistics describe the demographic distribution, area and type of practice and the usual hours worked per week of the four dental occupational groups. Where possible, the results are compared with those from previous dental labour force collections.
NEWS
Health Minister Nicola Roxon last month (January 2008) launched a program for nurses to visit Indigenous children and their families at their homes to ensure they get the support they need earlier.
Professor David Olds, the US-based architect of this revolutionary program, was present for the launch.
Australia is only the second country (after the United Kingdom) given permission to use this program. This is an important part of the Government's commitment to closing the 17-year life expectancy gap between Indigenous and non-Indigenous people within a generation.
This program, along with our other programs that are part of the government's $260 million down-payment on Indigenous women's and children's health, will help ensure that Indigenous children are healthy, happy and ready to learn. It is aimed at giving Indigenous children a healthier start in life through ongoing home visits.
The program will be based on the Nurse Family Partnership, pioneered in the United States by Professor Olds, Director of the Prevention Research Centre for Family and Child Health at the University of Colorado, USA. The Nurse Family Partnership has produced impressive short- and long-term benefits for children and their families and has been proven to improve the health, welfare and life choices of both mothers and their children.
Results have shown that children who receive the nurse visits have improved birth weights, cognitive ability and school readiness. Mothers smoke less, have increased intervals between births and have improved parental skills. They also use community services more effectively and are more likely to hold jobs.
Originally designed for first-time, financially-disadvantaged mothers, the Nurse Family Partnership will be adapted here to reflect the Australian health care system and the geographic and cultural diversity across Indigenous communities.
Most current home visiting programs in Australia provide only a single visit, often by a volunteer rather than a trained health professional. This new program is different - it will provide structured, sustained home visiting by skilled health professionals, starting from pregnancy and continuing through to the child's second birthday. In the long-term, the program aims to provide home visits to children up to the age of eight.
Professor Olds is currently in Australia for talks with the Government and Indigenous stakeholders about the introduction of this scheme. He is also meeting with key academics and health practitioners in the child and maternal health fields and visiting Indigenous communities in the Northern Territory as well as Queensland.
In the initial stage, the program will establish up to ten sites across Australia that will be funded under the Government's initiative Directions: an equal start in life for Indigenous children. Approximately 1,900 families will receive support, over five years, through both the New Directions and Health@Home Plus initiatives.
Consultations will soon commence on a wider roll-out of Indigenous mums and bubs program to enhance this intensive home visiting service.
Source: http://www.health.gov.au/
2. Expansion of Medicare-eligible MRI servicesThe Australian Government on 12 February 2008 confirmed the locations for the 2007-08 expansion of Medicare-eligible Magnetic Resonance Imaging (MRI) services.
MRI uses strong magnetic fields to generate images to assist in diagnosing illnesses. It is especially effective on soft tissue, making it important for diseases such as cancer and strokes. The 15 locations are:
NSW: Bankstown, Maitland-Newcastle-Hunter (replacing the previous Newcastle-Hunter location), Sutherland Shire, Wollongong Hospital;
VIC: Clayton-Oakleigh, Inner Melbourne;
QLD: Bundaberg, Cairns Base Hospital (replacing the previous Cairns location), Rockhampton Hospital;
SA: Morphett Vale, Port Augusta;
WA: Armadale, Joondalup; and
TAS: North-West Tasmania, Launceston General Hospital.
These locations take into account those announced in 2007 by the previous Government. In addition, it recognises that patients and communities value access to affordable MRI services. Therefore, expanding Medicare-eligible MRI services will improve access to this important diagnostic tool for many communities.
The Department of Health and Ageing is moving forward with the various application and direct listing processes for the confirmed locations. Where appropriate, the processes commenced by the previous government will be continued.
Further announcements about the outcomes of individual application and direct listing processes will be made by the Government as each is finalised.
Source: http://www.health.gov.au
3. New changes to Pharmaceutical Benefits Scheme (PBS) in 2008People with pleural mesothelioma, eye conditions, those who want to stop smoking, and infants with chest infections will benefit from changes to the Pharmaceutical Benefits Scheme (PBS) that commenced last month (January 2008).
The listing of pemetrexed disodium (Alimta) in combination with the drug cisplatin has been extended to include the treatment of pleural mesothelioma. About 300 patients are expected to use pemetrexed disodium each year, at a cost of around $26 million to the PBS and Repatriation Pharmaceutical Benefits Scheme (RPBS) between 2007-08 to 2010-11.
This is an important announcement, coming after the tireless campaigning of Bernie Banton, who recently passed away. Bernie was a great Australian hero, and it is due to his efforts that many people will understand the significance of this decision.
Vaxigrip junior is a new form of influenza vaccine suitable for children up to 35 months of age who are at risk of adverse consequences from lower respiratory tract infections (chest infections). This will provide doctors with a more convenient form of influenza vaccine for young children.
From 1 January 2008, optometrists authorised to prescribe certain preparations under State or Territory legislation will be able to apply to Medicare Australia for approval to prescribe a limited list of PBS eye medicines. This initiative will cost about $10.7 million over four years. It will improve access to eye treatments for many Australians, particularly concession card holders and people in rural areas.
The addition of varenicline (Champix) will help people who want to stop smoking. This is a new smoking cessation therapy treatment, which assists in reducing the craving and withdrawal symptoms that happen when a person gives up smoking. It is expected around 195,000 people will use varenicline in the first year of listing, at an additional cost to the PBS and RPBS of around $76.3 million over four years to 2010-11.
Further information about medicines subsidised by the Australian Government through the PBS is available at www.pbs.gov.au
Monika Bhatia
Editor, Health and Ageing
22 Februry 2008