8
Opportunities to Generate Evidence on Older Adults and Move the Research Agenda Forward
Several presenters revisited the studies discussed during the workshop, with an eye toward lessons learned and how other studies might benefit from previous experiences.
Thinking back to the origins of the Mexican Health and Aging Study (MHAS) in 1999, Rebeca Wong said important beginning steps were to identify the key and unique scientific issues that needed to be addressed, and to plan for longitudinal national data and open data access for the scientific community. One unique element in MHAS, she said, was a focus on the migration of older adults to and from the United States, and the MHAS sample includes recent migrants, historical migrants who migrated 40 or 50 years ago, and individuals with family networks in the United States.
Having the right partners was crucial, she said, because field work in a longitudinal study requires the ability to follow individuals over time if they move to another part of a country or within a large city. Not every organization or company can do this. Fortunately for MHAS, the Instituto Nacional de Estadística, Geografía e Informática (INEGI) was one of the partners. MHAS had Dr. Beth Soldo from the University of Pennsylvania as a principal investigator during the study’s first round and collaborated with researchers from other universities and with the National Geriatrics Institute. Now, with biomarkers in the survey, MHAS collaborates with the National Public Health Institute. Having proper partners for political support also is important, Wong noted.
As a longitudinal study proceeds, Wong continued, it is necessary to take care of data quality by investing in sample maintenance and followup response. This is not an easy task, she observed, but it can be accomplished by working with partners such as INEGI to develop strategies for re-contact. Another point is that no study has value if people do not use the resulting data. Study teams should make data available quickly after collection (in the case of MHAS, 9–12 months after a survey wave), facilitate data use, and assist with production and dissemination of publications and policy summaries.
Wong stressed the importance of recognizing major social changes that occur during a study’s lifetime. Between MHAS rounds 2 and 3, reform and extension of public insurance in Mexico with the goal of reaching universal coverage took place, as did a financial crisis in the United States and the rest of the world. Mexican migration to the United States was greatly reduced, and she said MHAS must assess the impact of insurance reform and the impact of the financial crisis on older Mexicans and their families both in Mexico and the United States. One out of five Mexicans aged 50 and older has at least one son or daughter in the United States.
William Dow, University of California, Berkeley, provided more details on the Costa Rican Study of Longevity Healthy Aging (CRELES), funded by the Wellcome Trust and the U.S. National Institute on Aging. Dow’s coprincipal CRELES investigator, Luis Rosero-Bixby, spoke earlier in the workshop (see Chapter 3) about the study’s original goal of understanding the extraordinarily high longevity of older adults in Costa Rica.
Dow explained CRELES has two different cohorts. Rosero-Bixby spoke about data from the original cohort, which included individuals born before 1945 who were sampled from the 2000 Costa Rican Census and hence were aged 55 and older in 2000. This group, interviewed in 2005, 2007, and 2009, included an oversample at very old ages. Sample attrition was about 6 percent between waves, and there was approximately 10 percent mortality between waves. For each death, the study team interviewed family members to learn more about circumstances leading up to and surrounding the death.
The second CRELES cohort is called the CRELES Retirement Cohort, and includes individuals born between 1945 and 1955. They were interviewed in 2010 and 2012. Part of the rationale for selecting this cohort was to study retirement decisions. Dow noted a very rapid fertility decline in Costa Rica during the 1960s, in particular, and that the two CRELES
cohorts span much of this period. Combining data from the cohorts should allow researchers to understand some of the long-term effects of the fertility decline.
Given CRELES was originally focused on mortality and health, the study includes numerous objective health measures, he said. Among them are anthropometry, blood pressure measurement, and observed functioning (e.g., grip strength, spirometry, standing on one foot, bending and crouching, timed walk), many of the items discussed in the workshop discussion about biomarkers. The original CRELES cohort provided fasting blood samples in the baseline survey and in the 2007 follow-up, and an overnight urine sample in 2005. With the more recent retirement cohort, investigators mimicked the indicators that were collected in the U.S. Health and Retirement Study, using nonfasting venous blood to measure glycosylated hemoglobin for diabetes, total HDL cholesterol, and C-reactive protein. There also are DNA samples from these individuals that have been used to look at, for example, leukocyte telomere length.
Going forward, Dow said there are no plans for new survey waves. Current work is focused on several fronts: (1) harmonizing the CRELES data in the University of Southern California’s Global Aging Data Repository with information from the many HRS-type studies from other countries; (2) integrating GIS-related data, such as a mapping of government health facilities (hospitals and clinics) and information from neighborhood questionnaires that were filled out by interviewers at the time of the interviews (CRELES also did a survey of clinics to measure clinic quality and related aspects); and (3) continuing to follow individuals in the death registry and developing links to other datasets. Linkages with civil registries allow researchers to follow changes in family structure over time, as well as new fertility events, address changes, and other changes. There is the potential to link to pension data, though this has not yet been done. With regard to mortality analysis, researchers also developed a database of 20,000 individuals aged 35 and older drawn from the 1984 Costa Rican census, and have been following them over time in the death registry. This is an example of the type of administrative data linkages that Dow encourages other studies to do in order to increase sample sizes for analyses.
Finally, he mentioned CRELES researchers have been working with environmental health sciences colleagues to use satellite data on weather and air quality, at the time of the surveys, in each of the small areas within the survey. Dow suggested other studies should consider the incorporation of such information.
Cesar de Oliveira spoke about two factors instrumental for the launch of the Brazilian Longitudinal Study of Aging and Wellbeing (ELSI-Brazil), described in Chapter 3. The first was the support of the Brazilian government through the Ministry of Health, which has provided full funding for the project. In any country, he noted, specific issues will be of particular importance. In the case of Brazil, assessment of public policies concerning older people (described by Cassio Turra during the workshop; see Chapter 6) are very important to the Ministry of Health. ELSI-Brazil has a special module addressing that topic. In other countries across Latin America and the Caribbean, said de Oliveira, the development of ELSI-Brazil-type studies might benefit from a focus on issues of country-specific importance.
The second factor, which has been mentioned in other sessions, is the role that the international community has played, particularly the close collaboration with researchers involved with the English Longitudinal Study of Ageing that helped define core survey modules and key variables. He suggested the experiences of MHAS and ELSI-Brazil would be of use for the development of new studies in other countries in Latin America and the Caribbean, particularly because most if not all countries share a history of social and health inequalities.
Somnath Chatterji, World Health Organization (WHO), spoke about the WHO experience in designing and fielding a multicountry study known as the Study on Ageing and Adult Health (SAGE).1 One of WHO’s core functions is the monitoring of health of trends and determinants, and WHO has been involved in the Global Burden of Disease study discussed during the workshop. Historically, however, WHO did not engage much in primary data collection. About 15 years ago, this began to change with the development of a large 70-country study called the World Health Survey that focused on various aspects of health and its determinants, largely in adult populations. At that point in time, a focus on aging was not central to what WHO was doing, and the importance of noncommunicable diseases in much of the world was not well recognized. Chatterji explained some aging experts around the world, notably Richard Suzman from the U.S. National Institute on Aging, began to question why there was not more attention given to older adults in this survey exercise. This served as the stimulus for WHO to think more specifically about older adults and the aging process.
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1See http://www.who.int/healthinfo/sage/en/ [August 2015].
WHO developed its Study on Ageing and Adult Health based on oversamples of adults aged 50 and older in several countries that participated in the World Health Survey. WHO has partnered with the HRS-type surveys to look not only at health and its determinants, but also the relationship between health and well-being. WHO recognized the need, as James Smith mentioned in his workshop presentation (see Chapter 2), to understand the circumstances in which people live and grow old, and therefore incorporated aspects of household living conditions, economics, subjective well-being, and time use into SAGE.
Six nationally representative SAGE surveys have been conducted, in China, India, Russia, Mexico, Ghana, and South Africa. The surveys involve about 45,000 people aged 50 and older, with a comparative cohort between the ages of 18 and 49, and incorporate most of the variables discussed during this workshop, including household health examinations and the collection of biomarkers using dry blood spots. Going forward, Chatterji said, SAGE will also collect DNA. The second wave of SAGE currently is in the field, and wave three will begin 2 years later.
Chatterji said since SAGE was launched, there has been a recognition within WHO that aging and the health of older adults is an important component of the public health agenda. The organization will issue a World Report on Aging in 2015 and launch its Global Action and Strategy on Aging. These developments would not have happened, he stated, without the support of the HRS family. WHO, as an intergovernmental organization, is concerned not only with research, but also with the use of evidence in policy formation, and is now engaged in knowledge translation exercises involving SAGE data from Ghana and China.
David Bravo revisited the beginnings of the longitudinal Social Protection Study in Chile in 2002 and reiterated Rebeca Wong’s points about the importance of academic support in the study’s development stages and with data development. He stressed the importance of maintaining the study given its demonstrated impact on public policy and promise for future analyses. He said it will be important to better link study data with civil registry and administrative data, and to consider the potential value added from incorporating measures found in HRS-type surveys. While such measures would increase costs, in his view, it would be very useful to add the additional dimensions of family structure, intergenerational transfers, and biomarkers.
It is necessary, he said, for Chile to have a survey of people aged 50 and older that is harmonized with HRS-type surveys. At the same time, he said,
it is necessary to better utilize information from other longitudinal studies in Chile that are not so well known, such as the health study described by Cecilia Albala (Chapter 7), and to focus on linking databases and samples. Financing for these efforts, he said, should come from within the country, although there is a role for international agencies as well.
Maria Teresa Calzada presented further information on the SABE Colombia study she described earlier (see Chapter 4). SABE Colombia is a joint initiative between the Colombian Ministry of Health and Social Protection and the Universidad del Valle in conjunction with the National Consultancy Center, an entity that does field work. Design and planning began in 2013, and a study sample was identified in 2014 based on a master sample from the Ministry of Health and Social Protection, which was interested in a focus on adults aged 60 and older. The SABE sample includes nearly 31,000 older adults living in households.
The SABE Colombia instrument contains 404 questions organized into 12 thematic groups. The study includes anthropometric measurements and assessments of functionality and will collect biomarkers from a subsample of respondents. SABE results will be complemented by data from a second, smaller (N = 1000) survey of caregivers conducted by the Universidad del Valle, which includes 70 questions designed to study caregiver burden. The SABE design also includes a qualitative component based on focus group interviews.
Several databases will be developed and become part of the National System for Health Population Studies and Surveys. SABE data will be readily available to the scientific community through two platforms maintained by the Ministry of Health and Social Protection. One, called SISPRO, is a comprehensive system for social information. The second, called ROSS, contains digital health information. Plans also call for the establishment of a serum repository of SABE biomarker samples within the Colombian National Health Institute. Calzada suggested working together with the ELSI-Brazil team on ways to make biomarker information available to scientific research.
In response to a participant question regarding the extent to which data can be derived from sources other than population surveys, Dow noted vast amounts of clinical data and medical records increasingly are computerized. He said in the United States, the HRS has been able to link to the vast trove of Medicare claims data, thus greatly increasing analytical power and possibilities. This model could prove valuable in other countries if the bureaucratic obstacles can be overcome.
Responding to a question from Carlos Cano about the value of biomarkers given their collection costs and uncertain clinical relevance, Dow pointed to the data reported by Soham Al-Snih showing the high percentage of undiagnosed diabetes, and stated that it is crucial to have information that cannot or is not captured in clinical settings. He argued much of what biomarkers can do is to provide preclinical indications of disease in individuals, as well as population-level warnings of what might emerge in the future. Further, he said it often is imperative to have objective measures of health status rather than relying on people’s self-reports, especially since the relationship between objective and subjective measures is seen to vary by socioeconomic status. Cecilia Albala said researchers should agree on a small set of key biomarkers to better influence public policy. She noted many studies measure C-reactive protein, but said this is not useful for policy.
Chatterji responded to participant comments suggesting that more emphasis should be given to improving the quality of data from existing health information systems. Chatterji said while it is important to improve current routine reporting systems, the fact is that fewer than one-third of WHO member countries are able to provide usable levels and causes of deaths. Waiting for present reporting systems to provide the necessary data for policymaking will be too late, he asserted. He stressed the need for more innovative methods of obtaining population health information, particularly surveys that can target behaviors and be linked to the growing quantity of information from other sources.
Enrique Vega, Pan American Health Organization, commented that the multinational SABE project in 1999–2000 represented a leap for the LAC region that at the time did not have a significant aging study. He said SABE spawned other national studies, including in Ecuador and Puerto Rico, that have not been mentioned during the workshop, and raised the profile of aging in the region. In 2009, the Americas was the first WHO region to develop an action plan on aging and health, and later in 2015 will become the first WHO region to approve, at the ministerial level, an action plan on dementia. He said many of the data and studies presented in the workshop have played a role in the development of public policy in the LAC region, and additional cross-national analyses are needed to move the policy process forward.
Several participants suggested the need to train students in how to use these increasingly complex data. Luis Rosero-Bixby agreed, noting most medically trained personnel in LAC do not have the corresponding training
and ability to use such data. Enrique Vega said politicians also need training in how to understand and interpret the results.
By way of conclusion, David Weir noted the purpose of the workshop was to discuss the needs for strengthening the scientific foundations for aging research, and the possibilities for doing so. Victor Garcia directly addressed the question of data needs, and Luis Miguel Gutiérrez gave a succinct picture of the complex lives of older people. Weir stated this complexity underlies the origins studies in the HRS network and explains why these studies employ a multidisciplinary approach to the assessment of older people’s lives. He also referred to the opening session of the workshop, when Eduardo Sojo commented that it is not necessary to reinvent the wheel. The HRS network has many wheels, he said, and now many good research models. Both Rebeca Wong and Fernanda Lima-Costa talked about how their respective studies in Mexico and Brazil have benefitted from the experience of the international community, and how they are now in a position to benefit other researchers interested in pushing the agenda forward.
Weir said while it may seem difficult and expensive to initiate longitudinal studies, there may be rich cross-sectional studies in some countries that have already identified participants, know their ages, and could be used as a basis for longitudinal samples. He explained the English Longitudinal Study of Ageing began by recruiting participants from the already-established English National Health Survey. He also pointed to the potential role of the international research community in helping build support for new studies, which proved useful in Brazil, India, and China.
Wong noted a group of researchers who are engaged in longitudinal studies meet every 2 years in different countries to discuss their projects. The group often tackles hard questions, such as about biomarkers, shares histories and experiences, discusses technical issues, and learns from each other. This type of information exchange affords researchers the opportunity to correct mistakes and try new approaches, she observed.
Gutiérrez suggested an important next step is to think strategically about funding. In Mexico, he said, responsible parties in the Ministry of Health and elsewhere in the government now recognize and understand the salience of the aging process. Mexico has had a program for the care of the elderly for 15 years, but the program has not had its own financing; rather, it is funded by global financing for chronic disease. What is needed is to better connect the type of research presented in the workshop with the health and caregiving costs that countries will encounter as their populations age, he urged, as more effective cost projections and potential savings projections would help persuade governments to reallocate resources.
