Abstracts

INTRODUCTION

Population ageing has been described as a global phenomenon. Brazil, unlike developed countries, has shown rapid growth in recent decades¹1 . Caramano AA. Envelhecimento da população brasileira: uma contribuição demográfica. In: Freitas EV et al. Tratado de Geriatria e Gerontologia. Rio de Janeiro: Guanabara Koogan; 2006. p. 88-105.. In 1977, the elderly accounted for 4.9% of the economically active population (EAP); in 1988, 9%, and expectations are that in 2020, they account for at least 13% of the economically active population²02 . Lopes do Nascimento RF, Argimon IIL, Lopes RMF. Atualidades sobre o idoso no mercado de trabalho. 2006. Disponível em: http://www.psicologia.pt/artigos/textos. (Acessado em 18 de maio de 2013).
http://www.psicologia.pt/artigos/textos... . The earned income of the elderly is crucial in the composition of their personal and family income, so that they can hardly expect compensatory mechanisms that allow them to lower their participation in the labor market³03 . Wajnman S, Oliveira AMHC, Oliveira EL. Os idosos no mercado de trabalho: tendências e consequências. Disponível em: http://www.ipea.gov.br/agencia/images/stories/PDFs/livros/Arq_23_Cap_14.pdf. (Acessado em 23 de maio de 2013).
http://www.ipea.gov.br/agencia/images/st... .

Work ability (WA) is the basis for well-being, and the variables that affect it may be influenced by factors related to the individual, the environment and life outside of work, according to the multidimensional conceptual model⁴4 . Gould R, Ilmarinen J, Järvisalo J, Koskinens S. Dimensions of work ability. Helsinki, Finland: Finnish Centre for Pensions, Waasa Graphics Oy; 2008.. Although functional ageing can be often noticed before chronological ageing in national⁵5 . d'Orsi E, Xavier AJ, Ramos LR. Trabalho, suporte social e lazer protegem idosos da perda funcional: Estudo Epidoso. Rev Saúde Pública 2011; 45(4): 685-92. and international⁶6 . Soer R, Brouwer S, Geertzen JH, van der Schans CP, Groothoff JW, Reneman MF. Decline of functional capacity in healthy aging workers. Arch Phys Med Rehabil 2012; 93(12): 2326-32. studies, there is evidence that formal or voluntary work⁷7 . Martinez IL, Frick K, Glass TA, Carlson M, Tanner E, Ricks M, et al. Engaging older adults in high impact volunteering that enhances health: recruitment and retention in the Experience Corps(r) Baltimore. J Urban Health. 2006; 83(5): 941-952. is an important protector of disability and is related to the maintenance of well-being, physical activity and active lifestyle life among the elderly⁷7 . Martinez IL, Frick K, Glass TA, Carlson M, Tanner E, Ricks M, et al. Engaging older adults in high impact volunteering that enhances health: recruitment and retention in the Experience Corps(r) Baltimore. J Urban Health. 2006; 83(5): 941-952. ^{, 8}8 . Seitsamo J, Tuomi K, Martikainen R. Activity, functional capacity and well-being in ageing Finish workers. Occupational Medicine 2007; 57(2): 85-91. .

Due to a greater susceptibility to conditions that reduce their ability to work, the elderly are frequent associated with impairments in body functions, difficulties in performing work activities and restrictions in social participation. However, it is noteworthy that the studies are not consistent with regard to the factors that promote the sustainability of the WA in the elderly, indicating a gap in the literature that needs to be completed for the development of public policies to promote the health of the elderly that remain at work.

The identification and stratification of risks in individual groups exposed to certain factors and conditions that place them in a position of priority for health care are important tools in the analysis of the health situation. Given the accelerated population ageing associated with increased participation of the elderly in the labor market, the aim of this systematic review was to summarize the evidence about the factors associated with maintenance of the work ability during the ageing process.

METHODS

This is systematic review of literature, exploratory in nature and of quantitative approach, which used a combination of the descriptors "assessment of work ability" AND "elderly" OR "ageing" AND "workers" and their Portuguese and Spanish equivalents, according to the health sciences descriptors (DeCS). Articles that had the searched keywords in its title or abstract and were published between 2000 and 2013 were screened. The search took place between March 29th and April 25th, 2013. A bibliographic survey was conducted in indexed databases MedLine, SciELO and LILACS.

Unlike the term "job performance", the concept of work ability in this review was based on studies by Ilmarinen⁹9 . Ilmarinen J, Tuomi K, Eskelinen L, Nygård CH, Huuhtanen P, Klockars M. Background and objectives of the Finnish research project on aging workers in municipal occupations. Scand J Work Environ Health. 1991; 17Suppl 1: 7-11., discussed by Sampaio and Augusto¹⁰10 . Sampaio RF, Augusto VG. Envelhecimento e trabalho: um desafio para a agenda da reabilitação. Rev Bras Fisioter 2012; 16(2): 94-101., which is the combination of human resources in relation to physical, mental and social demands of work activity, incorporating individual resources, factors related to work and the environment outside of work.

SELECTION OF ARTICLES

The selection of articles found with the search in different databases was conducted in three distinct stages. First, we selected items with abstracts available, with a quantitative methodology (cohort or cross-sectional), for the evaluation of AW and the effect of aging. We excluded studies whose samples did not include older people, those interested in analyzing the clinical course of age- and/or work-related illnesses and those published in the form of editorials, interviews, projects, clinical notes, preliminary or conceptual data, descriptive and revisions.

The articles found in journals should contain the terms listed above, not necessarily all, but the term "assessment of the work ability" was the primary inclusion factor, and should be related to ageing, with individuals that are healthy and/or capable of continuing with their work. They could not focus on diseases.

DATA EXTRACTION AND ANALYSIS

With the studies previously established, a reading was performed in an exploratory way, and a specific form was developed specifically to analyze the articles for the review and extract the data. This tool was based on the recommendations of The Cochrane Library¹¹11 . Higgins JPT, Green S, editors. Cochrane Handbook for Systematic Reviews of Interventions 4.2.6 [updated September 2006] . In: The Cochrane Library, Issue 4, 2006. Chichester, UK: John Wiley & Sons, Ltd., adjusted according to the interests of authors. The extraction of data considered the following:

The selection of articles was performed by two independent reviewers, based on information from the title and abstract of the articles. If there was some disagreement, the reviewers would read the study in its entirety, discuss and even consult a third reviewer. After this step, the data were consolidated into a database. Variables related to AW in the articles were categorized according to the didactic model described by Sampaio and Augusto¹⁰10 . Sampaio RF, Augusto VG. Envelhecimento e trabalho: um desafio para a agenda da reabilitação. Rev Bras Fisioter 2012; 16(2): 94-101. and presented in this review if there was a statistically significant relationship with the outcome measure indicated by the studies.

RESULTS

In the search performed, 924 articles were obtained after defining descriptors and applying the inclusion criteria. The characteristics of the articles selected are presented in Tables 1 and 2. Among the 17 studies included, the number of longitudinal studies with follow-up represented minority (35.2%), with mean follow-up of 4.8 years (SD ±3,9 years). Although only studies involving elderly in the sample have been selected, the result reveals that only 35.2% of these studies investigated individuals above 60 years of age who had some sort of work activity. Brazil represented the largest number of publications on the topic, representing 41.1% of the studies analyzed, but conducted only cross-sectional studies (64.7% of the total).

The instruments for outcome assessment used by most articles were: Work Ability Index (WAI) (35.2%), self-rated health (35.2%), SF-12 (23.5%), Instrumental Activities of Daily Living scale (IADLs), of life satisfaction, and the Nordic Musculoskeletal Questionnaire (NMQ) (17.6%).

Being satisfied with life (17.6%), having higher income (11.7%), doing any kind of physical activity (11.7%), volunteering (5.8%) and mental labor demand (5.8%) were presented as positive associations of the determinants against functional loss (Table 3). Table 4 shows the main negative associations, identified as risk variables, which showed correlation with WA. Noteworthy are the variables being elderly (41.1%), not having a partner, physical demand at work (11.7%), being a smoker and prolonged time of service in years (5.8%). The variables education, health status, comorbidity, functionality, cognition and number of hours worked in the week showed no statistically significant associations.

DISCUSSION

The relationship between ageing and work is being approached from different aspects. In this review, the fact that the elderly remains inserted in the labor market, which leads to a good expectation of its future, is reinforced. The main associations that negatively influence the WA, such as age, smoking, time of service in years and physical work demands, are stressed. The positive association between factors that can maintain a good WA during the ageing process tend to satisfaction with life, better financial conditions, regular physical activity, volunteer work and occupational activities with prevalence of mental demand, protecting the elderly from functional declines.

Due to the heterogeneity of the sample, the small number of articles included at the end of this review and the different statistical methods applied, it was constrained in inferences regarding the magnitude and the impact of factors associated with WA in the elderly, since the tendency of the results cannot be accurately measured, a situation often found in systematic reviews of observational studies¹²12 . Egger M, Smith GD, Altman DG. Systematic reviews in health care: meta-analysis in context. London: Publishing Group, 2007.. However, in this review, 41.1% of the studies presented estimates of relative risk, odds ratio or attributable risk, which are important to verify the association between exposures and outcomes. The statistical power is not the best indicator to analyze the susceptibility of the study for being biased¹²12 . Egger M, Smith GD, Altman DG. Systematic reviews in health care: meta-analysis in context. London: Publishing Group, 2007., being also necessary to determine the sample composition and size. Few studies have examined only the elderly and the majority of studies were cross-sectional and, as a consequence, causality could not be determined.

Further studies on this topic are worth mentioning, and this review does not exhaust the possibility that other relevant evidence have not been located for being available in other bases, sources or different languages from those considered. However, the selection of studies included only considered publications in databases that require peer review of submitted articles, which gives them greater credibility regarding the methodology used.

Schwingel¹³13 . Schwingel A, Niti MM, Tang C, Ng TP. Continued work employment and volunteerism and mental well-being of older adults: Singapore longitudinal ageing studies. Age Ageing 2009; 38(5): 531-7. describes that seniors who volunteer and/or to remain active and busy after retirement have better cognitive conditions, greater life satisfaction, well-being and continue to exert their ADLs independently. Elderly who engage in productive activities are less likely to develop frailty syndrome regardless of age¹⁴14 . Jung Y, Gruenewald TL, Seeman TE, Sarkisian CA. Productive activities and development of frailty in older adults. J Gerontol B Psychol Sci Soc Sci. 2009; 65Bi(2): 256-61.. Aged people who retire and become inactive have higher rates of depression¹³13 . Schwingel A, Niti MM, Tang C, Ng TP. Continued work employment and volunteerism and mental well-being of older adults: Singapore longitudinal ageing studies. Age Ageing 2009; 38(5): 531-7..

Staying in the labor market seems to be strongly determined by physical capacity. Longitudinal study by Savinainen et al.¹⁵15 . Savinainen M, Nygard CH, Ilmarinen J. Workload and physical capacity among ageing municipal employees - a 16-year follow-up study. International Journal of Industry Ergonomics 2004; 34: 519-33. concluded that the strength of isometric trunk extension and good aerobic capacity are found most often in workers with low workload, less time and intensity of exposure to physical work activity. These data may explain the emergence of work-related diseases and injuries^l.

Regular physical activity can be an important tool for health promotion for older people to continue working. In this review, sectional and longitudinal studies show the effects of this regular practice on the performance at work, thus corroborating the revisions by Kenny¹⁶16 . Kenny GP, Yardley JE, Martineau L, Jay O. Physical work capacity in older adults: implications for the aging worker. Am J Ind Med. 2008; 51(8): 610-25. and Crawford¹⁷17 . Crawford JO, Graveling RA, Cowie HA, Dixon K. The healthy safety and health promotion needs of older workers. Occupational Medicine 2010; 60(3): 184-92., in which the protection of the elderly against functional loss at work was evidenced. The increase in oxygen consumption by 25%, and consequently the improvements in cardiorespiratory and muscular performance, the promotion of sociability, mental and emotional well-being are directly linked to improved self-perceived health, and a strong association has been shown with the lowest rate of absenteeism¹⁸18 . Seibt R, Spitzer S, Blank M, Scheuch K. Predictors of work ability in occupations with psychological stress. J Public Health. 2009; 17(1): 9-18. ^{- 19}19 . Pohjonen T. Perceived work ability of home care workers in relation to individual and work-related factors in different age groups. Occup Med (Lond) 2001; 51(3): 209-17..

The relationship of gender and social participation were not apparent in the primary studies in this review, whether by low statistical power or lack of association, contrary to what we expected. Females are increasing participation in the labor market, prevailing the double shift, justified by lower incomes and need for relationships, not by satisfaction. These events put them at disadvantage in maintaining WA compared with males²¹21 . Pérez ER. Saúde e Trabalho dos Idosos em São Paulo: um estudo através da SABE. (Dissertação de Mestrado). Centro de Desenvolvimento e Planejamento Regional da Faculdade de Ciências Econômicas, Universidade Federal de Minas Gerais. Disponível em: http://www.cedeplar.ufmg.br/demografia/dissertacoes/2005/ELISENDA_RENTERIA_PEREZ.pdf.
http://www.cedeplar.ufmg.br/demografia/d... . According to Pèrez²¹21 . Pérez ER. Saúde e Trabalho dos Idosos em São Paulo: um estudo através da SABE. (Dissertação de Mestrado). Centro de Desenvolvimento e Planejamento Regional da Faculdade de Ciências Econômicas, Universidade Federal de Minas Gerais. Disponível em: http://www.cedeplar.ufmg.br/demografia/dissertacoes/2005/ELISENDA_RENTERIA_PEREZ.pdf.
http://www.cedeplar.ufmg.br/demografia/d... , it has been increasingly observed that elderly adults provide financial aid to their adult sons and daughters, a phenomenon called intergenerational transfer.

In relation to social participation, studies indicate that work is a source of maintenance of independence in ADLs, because the contact with other people provides fundamental relations of cooperation and interactivity. The labor activity may also involve mechanisms of beneficial competition to some extent, since they involve daily challenges that keep the worker active and assist in maintaining functional capacity¹³13 . Schwingel A, Niti MM, Tang C, Ng TP. Continued work employment and volunteerism and mental well-being of older adults: Singapore longitudinal ageing studies. Age Ageing 2009; 38(5): 531-7. ^{, 14}14 . Jung Y, Gruenewald TL, Seeman TE, Sarkisian CA. Productive activities and development of frailty in older adults. J Gerontol B Psychol Sci Soc Sci. 2009; 65Bi(2): 256-61. ^{, 21}21 . Pérez ER. Saúde e Trabalho dos Idosos em São Paulo: um estudo através da SABE. (Dissertação de Mestrado). Centro de Desenvolvimento e Planejamento Regional da Faculdade de Ciências Econômicas, Universidade Federal de Minas Gerais. Disponível em: http://www.cedeplar.ufmg.br/demografia/dissertacoes/2005/ELISENDA_RENTERIA_PEREZ.pdf.
http://www.cedeplar.ufmg.br/demografia/d... ^{, 22}22 . Gómez-Lomelí ZM, Dávalos-Guzmán JC, Celis-de la Rosa AJ, Ozozco-Valerio MJ. . Gac Med Mex 2010; 146(2): 90-7..

The mental demand of work was shown as positive association that can protect the elderly from the loss of WA. The reverse relationship is also true, in that the work preserves cognitive function during ageing. The memory, learning, attention and information processing are influenced by the kind of work and ageing itself, which can be reversed with the development of competence to perform the work²⁰20 . Martinez MC, Latorre MRDO, Fischer FM. Capacidade para o trabalho: revisão de literatura. Cien Saude Colet. 2010; 15(1): 1553-61.. These changes do not occur in a systematic manner, and can be compensated by experience, ability to work independently and greater bonding to their jobs that older workers tend to have²⁰20 . Martinez MC, Latorre MRDO, Fischer FM. Capacidade para o trabalho: revisão de literatura. Cien Saude Colet. 2010; 15(1): 1553-61.. It is recommended, therefore, that high productivity demands, stress, time pressure and complex decisions be avoided by the elderly, but the workload should be adjusted in order to promote the social inclusion process²³23 . Luis BL, Diaz S. Revisión bibliográfica de la capacidad funcional en trabajadores mayores de 65 años. Med Segur Trab 2011; 57(222): 63-76..

The decline in sensory function and deterioration of muscle performance may explain work accidents. The review by Luis and Díaz²³23 . Luis BL, Diaz S. Revisión bibliográfica de la capacidad funcional en trabajadores mayores de 65 años. Med Segur Trab 2011; 57(222): 63-76. points out that falls remain one of the most frequent events. These data provide important information to our study, in which none of the articles addressed the relationship between these variables, possibly because studies involving workplace accidents were excluded.

The evaluation of WA should include physical, mental and social abilities, as well as other disabilities²⁴24 . Chan G, Tan V, Koh D. Ageing and fitness to work. Occup Med 2000; 50(7): 483-91.. In addition to clinical or laboratory measures, several authors have suggested the use of the WAI as a practical means to monitor the changes related to the functional ageing of workers. In the studies included in this review, 35.2% have adopted the WAI as an outcome measure, determining which workers need support from health services. Costa et al.²⁵25 . Costa AF, Puga-Leal R, Nunes IL. An exploratory study of the work ability index (WAI) and its components in a group of computer workers. Work. 2011; 39(4): 357-67. demonstrated a negative relationship between all items of the WAI and age and point out that the use of this instrument can make the workplace better adapted to the elderly. Although the Brazilian version has been translated²⁶26 . Tuomi K, Ilmarinen J, Jahkola A, Katajarinne L; Tulkki A. Índice de capacidade para o trabalho. São Carlos: EduFSCar; 2005., validated and has good psychometric properties²⁷27 . Martinez MC, Latorre MRDO, Fischer FM. Validade e confiabilidade da versão brasileira do Índice de Capacidade para o Trabalho. Rev Saúde Pública 2009; 43(3): 525-32., it has not yet been developed for longitudinal studies to establish normative values according to the WAI scores for the general population and in the elderly.

Our findings support a study conducted by van den Berg et al.²⁸28 . van den Berg T, Robroek SJ, Plat JF, Koopmanschap MA, Burdorf A. The importance of job control for workers with decreased work ability to remain productive at work. Int Arch Occup Environ Health 2011; 84(6): 705-12. when analyzing the determinants of WA related to the instrument. Unlike our study, the authors emphasize overweight, changes in body balance, low income, high mental demands and lack of job autonomy as negative associations for the loss of ability to work.

CONCLUSION

This review shows a shortage of studies in elderly inserted in the labor market, despite the great importance of the subject and of numerous publications related to diseases. Likewise, few studies have reported the value of older workers as a healthy individual who is able to continue their work activities.

The permanence of elderly people in the labor market becomes increasingly emerging, since the Health Care and Social Security systems have shown their bankruptcy. However, to keep working requires careful adjustments so that undesirable damage to the elderly are avoided or minimized. The work was considered positive in this study as an important protective mechanism against depression, disability and frailty, maintaining well-being, good cognitive function and independence in daily activities. However, for this to occur, greater investment in the health of this population are needed, particularly with regard to musculoskeletal and cardiorespiratory fitness, and physical activity in the workplace should be encouraged by incentive policies as a health promotion strategy. Alcohol consumption, long working hours and physical demands of work activity were negatively associated with WA, which may favor the early functional ageing. However, more longitudinal studies, mainly Brazilian, are needed to determine causality of these factors among the elderly.

REFERENCES

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