Are the national guidelines for health behaviour appropriate for older Australians? Evidence from the Men, Women and Ageing project
Abstract
Aim: To review findings from the Men, Women and Ageing (MWA) longitudinal studies and consider their implications for national health guidelines.
Methods: Guidelines for good health for older adults in the areas of body mass index (BMI), physical activity, alcohol consumption and smoking behaviours are compared with MWA findings.
Results: Findings from MWA suggest that current BMI guidelines may be too narrow because BMI in the overweight range appears to be protective for both older men and women. Across all levels of BMI, even low levels of physical activity decrease mortality risk compared with being sedentary. Our findings suggest that consideration should be given to having different alcohol guidelines for older men and women and should include recommendations for alcohol-free days. The benefit of quitting smoking at any age is apparent for both women and men.
Conclusions: Current national guidelines in the areas discussed in this paper should be reviewed for older people.
Maintaining health and independent living are an increasingly important aim of Australia's rapidly expanding older population and, for this reason, the Australian Government established Ageing Well, Ageing Productively as a National Research Priority goal in 2003. In 2004, the National Health and Medical Research Council (NHMRC) and the Australian Research Council announced a joint strategic funding initiative to support this goal. The aim of this program was to develop an evidence base of research on ageing to inform policy and practice in Australia. This evidence was to provide the platform for setting priorities and defining strategies that would improve the health and well-being of older adults. The Men, Women and Ageing (MWA) project received funding for a 5-year program to capitalise on two existing large-scale, longitudinal studies: the Australian Longitudinal Study on Women's Health (ALSWH) involving a national sample of older women (1921–26 birth cohort) and the Health in Men Study (HIMS) involving older men from Perth, Western Australia. The general hypothesis underlying the MWA project was that there may be sex-specific differences in risk factors for mortality and morbidity in older age that are potentially amenable to intervention, and that these risk factors are not necessarily the same as those operating in younger adulthood. The aim of this paper is to review and provide commentary on findings arising from the MWA project and to consider the implications of these results for policy.
The two studies that form the Men, Women and Ageing project
The ALSWH is a nationally representative, longitudinal study of the health and well-being of three cohorts of women who were aged 18–23 years (1973–78 birth cohort), 45–50 years (1946–51 birth cohort) and 70–75 years (1921–26 birth cohort) when recruited in 1996. The study uses mailed questionnaires to collect self-report data on health and related variables every 3 years. Women were selected from the Australian national health insurance database (Medicare), which includes all citizens and permanent residents. Stratified random sampling was used with intentional oversampling of women from rural and remote areas. In the 1921–26 birth cohort, 39 000 women were initially invited to participate; of these 1100 were not contactable and 2366 were ineligible. Of the remaining women (35 534), 12 614 responded. This cohort were aged 70–75 when first surveyed in 1996, and have been resurveyed in 1999, 2002, 2005 and 2008 to provide five waves of longitudinal data on women now in their 80s. Most women were Australian-born (68%), and another 22% were born in another English-speaking country or in Europe. The project has already generated substantial scientific output through peer-reviewed journal papers, policy-relevant reports, numerous conference presentations and invited keynote lectures. Findings have contributed significantly to policy development, in areas ranging from continence management and quality use of medicines, to mental health among older women.
The HIMS cohort was formed from a community-representative sample of men who were originally recruited into a randomised trial of screening for abdominal aortic aneurysm that was conducted in Perth, Western Australia in 1996–98. Eligible men were aged 65–79 years, resident in Perth (the capital of Western Australia), and not in long stay institutional accommodation. A list of all potentially eligible men was drawn from an electronic copy of the electoral roll in 1996 (voting is compulsory for adult Australians) and, after excluding 8801 who were no longer resident in Perth and 2296 who had died, the remaining men were randomised into the screening group (n= 19 352) or control group (n= 19,352). Of those invited to be screened, 1836 were ineligible, 5303 did not respond or refused and 12 203 were screened. These 12 203 screened men formed the HIMS cohort and have been continuously followed since their recruitment using health administrative record linkage and new postal and face-to-face surveys. Among these men, 55% were Australian-born and 37% were born in Europe.
The detailed methods for both studies have been described elsewhere [1,2]. Early discussions between the ALSWH and HIMS investigators resulted in harmonisation of questionnaires.
Men, Women and Ageing and current guidelines for health and well-being in older adults
The promotion of good health practices has been an international focus particularly since the inception of the World Health Organization (WHO) in 1948. WHO has generated norms and standards for health and has promoted policies that have been adopted and pursued by many governments worldwide. While a large number of guidelines and recommendations for promoting and sustaining good health have been developed, few of these focus specifically on older adults. This paper focuses on four areas where the findings of our research are relevant to national guidelines and recommendations for older adults: healthy weight, physical activity, alcohol consumption and tobacco smoking.
Body mass index
World Health Organization has classified thresholds for healthy weight, defined by body mass index (BMI), that are largely based on evidence from studies of morbidity and mortality risk in young to mid-aged adults [3,4]. The categories suggested are: underweight (less than 18.5 kg/m2), normal weight (18.5 to 24.9 kg/m2), overweight (25.0 to 29.9 kg/m2) and obese (more than 30.0 kg/m2). While WHO acknowledges the limitations of available reference data for older people, it makes no specific recommendations for optimal BMI in late adulthood. Further, there are no distinctions among BMI recommendations for differences attributable to sex.
Research on optimal BMI in older adults has recently been summarised in meta-analyses which have shown that the risk of mortality associated with BMI in the overweight range decreases with increasing age [5]. Previous work in younger adults has suggested that physical activity may ameliorate the health hazard of obesity for both men and women [6]; however, the question of the joint effect of BMI and physical activity on mortality remains unresolved, particularly for people over the age of 70 years. Recently, both weight and physical activity have been targeted by Australian Government public health campaigns as important, potentially modifiable lifestyle risk factors. The examination of these factors in relation to mortality in older Australian men and women was therefore one of the first studies undertaken by the MWA project. Our aim was to examine the level of BMI associated with the lowest mortality risk in older people (taking level of physical activity into account) and to determine if there were sex differences in this association [7]. Analyses revealed that mortality risk was lowest in the overweight BMI category, with minimum risk at BMI of between 26 and 27. Sex did not affect the relationship, with similar relative effects observed for both men and women [7].
Physical activity
Although there are specific recommendations for optimum physical activity for older adults (over 65 years of age) [8], these are based largely on evidence in the 1996 US Surgeon General's report on physical activity and health [9], which summarised data from earlier large cohort studies, most of which involved male, mid-aged participants. Although updates of the evidence were used to inform the development of the National Physical Activity Guidelines for Older Australians [10], there were comparatively few data from large cohort studies of older people. The guidelines suggest that older adults should perform some form of physical activity, suitable to their age and health status, on as many days of the week as possible. Specifically, older adults are advised to accumulate at least 30 minutes of moderate intensity physical activity on most days. There are no sex-specific recommendations.
Our findings have demonstrated that the effect on mortality of being sedentary differed for men and women, with the protective effect of physical activity more pronounced in women than in men. Being sedentary doubled the mortality risk in women across all levels of BMI, but resulted in only a one-third greater risk for men [7].
Alcohol consumption
Recommendations on alcohol consumption released in 2009 by the NHMRC [11] are for no more than two standard drinks on any day for adult men and women. These guidelines provide no recommendations specifically for older adults, although people over the age of 60 years who drink alcohol are identified as members of a potentially high-risk group. This identification has largely been based on theoretical concerns about the alterations in the distribution and metabolism of alcohol that occur with ageing and the potential for interactions with the increased number of medications commonly prescribed to older people. Evidence of the risks and benefits of drinking alcohol in late adulthood suggests that light to moderate alcohol consumption (one to two drinks per day) by older adults may lower the risk of some chronic conditions; however, this is tempered by the increased risk of falls and injuries associated with alcohol use in older adults [11]. Although the Australian guidelines refer to men and women, no specific sex differences of the effects of alcohol are described.
While high levels of alcohol use are generally regarded as detrimental for older people, there is little research evidence on the amount or frequency of alcohol consumption that constitutes high levels in this age group. Among MWA participants, the risk of all-cause mortality was lower in men who reported using up to four standard drinks per day and in women who reported one or two drinks per day, compared with older adults who did not usually consume alcohol in a normal week. We found, however, that for older men, mortality risk was reduced further if consumption was associated with one or two alcohol-free days per week (there were insufficient data to obtain reliable estimates for older women) [12].
Tobacco smoking
Tobacco smoking has been clearly and consistently linked to increased morbidity and mortality and has been identified as a major driver of health-care costs worldwide. The WHO's Framework Convention on Tobacco Control [13] was ratified by the Australian Government in 2004 and led to the development of the National Tobacco Strategy [14]. While the dose–response relationship between cigarette consumption and numerous respiratory and cardiovascular diseases has been well documented, there is less evidence on sex differences in the magnitude of risk associated with smoking, especially in older adults. Results from MWA have shown that all-cause and cause-specific mortality hazards associated with smoking were very similar for men and women for the same levels of amount smoked. Additionally, for past smokers (both men and women), the longer the time since quitting, the lower the risk of death. Our results provide powerful evidence that the harmful effects of smoking are the same for men and women and, indeed, women who smoke like men die like men who smoke [15]. Moreover, the benefits of quitting, for both men and women, are substantial even at older ages.
Implications of our findings for policy
Our findings stress several important issues relating to current Australian guidelines in the areas of BMI, physical activity, alcohol and smoking. MWA results suggest that evidence from younger adults may not be generalisable to older adults. For instance, our findings, and a substantial body of evidence from other countries [5,7,16], on BMI and mortality show that the WHO BMI thresholds for overweight and obesity are overly restrictive for older people. Our study suggests that risks and benefits in relation to weight for people who survive to age 70 in reasonable health may be different from those for younger people. Possibly, changes in body composition with ageing may mean that BMI is a less appropriate indicator of health risk in older adults than it is in younger people [16]. Our data suggest that Australian guidelines should be reviewed to reflect this important age-related difference in optimal BMI.
Our analyses also stress the importance of age-related recommendations for physical activity. While current physical activity guidelines emphasise the importance of any physical activity for older adults [8], our analyses show that women may gain more benefit than men for the same level of physical activity.
We also observed sex differences in the relationship between alcohol consumption and mortality which are not reflected in the recently updated guidelines published by the NHMRC [11]. The current guideline of two standard drinks per day may be appropriate for older women, but for older men lowest mortality risk is associated with an alcohol intake of up to four standard drinks per day, accompanied by one or two alcohol-free days per week. We acknowledge, however, that further work is required to determine whether the incidence of events, such as injuries, are also lower in older men who drink up to four standard drinks per day. Earlier Australian alcohol guidelines reflected the importance of alcohol-free days, but this recommendation is absent in the latest guidelines [17].
In contrast to the sex differences apparent in physical activity and alcohol, our results on smoking show that tobacco is equally harmful for older men and women, and there are benefits of quitting even in late adulthood. This finding provides further evidence for the National Tobacco Strategy's Quit campaign [14] and emphasises that it is never too late to reap the health benefits of smoking cessation.
An important caveat is that the MWA analyses reported here examined these health factors in relation to mortality but not morbidity. Successful ageing is related not only to length of life, but also to quality of life. For example, the influence of excess weight on conditions such as arthritis or diabetes may substantially reduce the ability of an older person to participate in many social and physical activities that could enhance life satisfaction.
Conclusion
The MWA project was conceived and funded to provide a rich and unique source of data on the health of older Australians. In particular, the project has focused on the role of sex and its influence on ageing well and successfully. Sex is an important factor in shaping people's social and biological experiences of ageing. While women have longer life expectancy than men in most parts of the world, they are also more likely to report higher morbidity, and have lower levels of education and financial security. Evidence that is accruing from this project and other studies worldwide suggests that both age and sex may differentially influence risk factors for optimal health and well-being in older adults and that these differences should be reflected in the national guidelines.
Acknowledgements
We thank participants of the ALSWH and the HIMS for their valuable contribution to this project. We also thank Dr Judy Straton for her helpful comments on this manuscript.
We would like to acknowledge the contribution of Professor Konrad Jamrozik, who died in March 2010. Professor Jamrozik was instrumental in the conception of the MWA project and was involved in the studies and the policy implications discussed in this paper.
The MWA project is funded by an NHMRC of Australia/Australian Research Council Ageing Well, Ageing Productively Strategic Award (409953). The SLSWH is funded by the Australian Government Department of Health and Ageing. The HIMS has been supported by grants from the National Health and Medical Research Council of Australia (project grant numbers 279408, 379600, 403963) and the BUPA Foundation (project grant DS 080608).
Key Points
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Current guidelines and recommendations for good health may not all be appropriate for older adults.
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Body mass index in the overweight category is associated with lower mortality risk than the normal weight category in both older men and women.
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Across all levels of BMI, even low levels of physical activity are associated with lower mortality risk compared with being sedentary.
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Consideration should be given to having different alcohol guidelines for older women and men; a recommendation on alcohol-free days should be included.
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The benefit of quitting smoking at any age is apparent for both men and women.
