Abstract
Background and aims: Relatively little is known about how region of residence influences frailty of seniors. Frailty indexes can be used to investigate these effects. We constructed and validated a frailty index, to investigate the differences in health status between rural and urban seniors. Methods: We studied rural (n=949) and urban (n=7598) older adults in the Canadian Study of Health and Aging, of whom 22% died over 72 months. The frailty index was generated from 40 self- reported health deficits (symptoms, diseases, disabilities, unfavourable living conditions). Results: The average value of the frailty index increased exponentially with age in both groups (rural: r=0.94; urban: r=0.97, p<0.01) and was highly correlated with mortality (r=0.96 for rural, r=0.97 for urban, p<0.01). Up to age 80, there were few rural- urban differences in frailty. After age 80, the rural sample showed higher mortality than the urban sample. The hazard ratio for death for each increment in the frailty index was 1.38 (1.14–1.72) in rural participants vs 1.18 (1.11–1.26) in urban participants. Women lived longer than men at any index value. Conclusions: Frailty index analysis readily summarizes health and mortality differences between very old rural and urban dwellers, which reflect differences in deficit accumulation, and in the impact of gender on survival. The frailty index provides efficient dimensionality reduction for studying group differences in the health of older adults.
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References
Hays RB. Common international themes in rural medicine. Aust J Rural Health 1999; 7: 191–4.
Eberhardt MS, Ingram DD, Makuc DM, et al. Urban and Rural Health Chartbook. Health, United States, 2001. Hyattsville, Maryland: National Center for Health Statistics, 2001.
Eberhardt MS, Pmuk ER. The important of place of residence: examining health in rural and nonrural areas. Am J Public Health 2004; 94: 1682–6.
Shields M, Tremblay S. The health of Canada’s communities. Health Reports 2002; 13 (Suppl): 1–24.
Statistics Canada. 2001 Census Analysis Series: A Profile of the Canadian Population: Where We Live. 2002.
Vukmir RB, Sodium Bicarbonate Study Group. The influence of urban, suburban, or rural locale on survival from refractory pre-hospital cardiac arrest. Am J Emerg Med 2004; 22: 90–3.
Bassuk SS, Berkman LF, Amick BC. Socioeconomic status and mortality among the elderly: findings from four US communities. Am J Epidemiol 2002; 155: 520–33.
Meyer HE, Berntsen GKR, Søgaard AJ, et al. Higher bone mineral density in rural compared with urban dwellers: The NOREPOS Study. Am J Epidemiol 2004; 160: 1039–46.
Hogan DB, MacKnight C, Bergman H, et al. Canadian initiative on frailty and aging. Models, definitions, and criteria of frailty. Aging Clin Exp Res 2003; 15 (3 Suppl): 1–29.
Gill TM, Kurland BF. Prognostic effect of prior disability episodes among nondisabled community-living older persons. Am J Epidemiol 2003; 158: 1090–6.
Fried LP, Ferrucci L, Darer J, et al. Untangling the concepts of disability, frailty, and comorbidity: implications for improved targeting and care. J Gerontol A Biol Sci Med Sci 2004; 59: 255–63.
Gill TM, Allore H, Holford TR, et al. The development of insidious disability in activities of daily living among community-living older persons. Am J Med 2004; 117: 484–91.
Yates FE. Complexity of a human being: changes with age. Neurobiol Aging 2002; 23: 17–9.
Bennett AK. Older age underwriting: frisky vs frail. J Insur Med 2004; 36: 74–83.
Rockwood K, Fox RA, Stolee P, et al. Frailty in elderly people: an evolving concept. CMAJ 1994; 150: 489–95.
Morley JE, Perry HM III, Miller DK. Something about frailty. J Gerontol Med Sci. 2002; 57A: M698–704.
Mitnitski AB, Mogilner AJ, Rockwood K. Accumulation of deficits as a proxy measure of aging. Scientific World Journal 2001; 1: 323–36.
Rockwood K, Mitnitski A, MacKnight C. Some mathematical models of frailty and their clinical implications. Rev Clin Gerontol 2002; 12: 109–17.
Mitnitski AB, Mogilner AJ, MacKnight C, et al. The mortality rate as a function of accumulated deficits in a frailty index. Mech Ageing Dev 2003; 123: 1457–60.
Mitnitski AB, Song X, Rockwood K. The estimation of relative fitness and frailty in community-dwelling older adults using self-report data. J Gerontol A Biol Sci Med Sci 2004; 59: M627–32.
Rockwood K, Mogilner A, Mitnitski AB. Changes with age in the distribution of a frailty index. Mech Ageing Dev 2004; 124: 517–9.
Canadian Study of Health and Aging Working Group. Canadian Study of Health and Aging: study methods and prevalence of dementia. CMAJ 1994; 150: 899–913.
Canadian Study of Health and Aging Working Group. The incidence of dementia in Canada: The Canadian Study of Health and Aging Working Group. Neurology 2000; 55: 66–73.
Rockwood K, Wolfson C, McDowell I. The Canadian Study of Health and Aging. Int Psychogeriatr 2001; 13 (Suppl 1): 1–237.
Teng EL, Chui HC. The modified mini-mental state (3MS) examination. J Clin Psychiat 1987; 48: 314–8.
Song X, Mitnitski AB, MacKnight C, et al. Assessment of individual risk of death using self-report data: an artificial neural network compared with a frailty index. J Am Geriatr Soc 2004; 52: 1180–4.
Fried LF, Katz R, Sarnak MJ. Kidney function as a predictor of noncardiovascular mortality. J Am Soc Nephrol 2005; 16: 3728–35.
Porell FW, Miltiades HB. Regional differences in functional status among the aged. Soc Sci Med 2002; 54: 1181–98.
St John PD, Havens B, van Ineveld CHM, et al. Rural-urban differences in health status of elderly Manitobans. Can J Rural Med 2002; 7: 89–93.
Milan G, Iavarone A, Vargas NF, et al. Effects of demographic and environmental variables on cognitive performance in a rural community sample of elderly people living in Southern Italy. Aging Clin Exp Res 2004; 16: 398–402.
Coburn AF, EH Kilbreth, SH Long, et al. Urban-rural differences in employer-based health insurance coverage of workers. Medical Care Research and Review 1998: 55: 484–96.
Eng PM, Rimm EB, Fitzmaurice G, et al. Social ties and change in social ties in relation to subsequent total and cause-specific mortality and coronary heart disease incidence in men. Am J Epidemiol 2002; 155: 700–9.
Steenland K, Henley J, Calle E, et al. Individual- and area-level socioeconomic status variables as predictors of mortality in a cohort of 179,383 persons. Am J Epidemiol 2004; 159: 1047–56.
Rothwell N, Bollman RD, Tremblay J, et al. Migration to and from rural and small town Canada. Rural and Small Town Canada Analysis Bulletin 2002; 3: 1–24.
Rockwood K. What would make a definition of frailty successful? Age Ageing 2005; 34: 432–4.
Jones DM, Song X, Rockwood K. Operationalizing a frailty index from a standardized comprehensive geriatric assessment. J Am Geriatr Soc 2004; 52: 1929–33.
Mitnitski AB, Song X, Skoog I, et al. Relative fitness and frailty of elderly men and women in developed countries and their relationship with mortality. J Am Geriatric Soc 2005; 53: 2184–9.
Rockwood K, Song X, MacKnight C, et al. A global clinical measure of fitness and frailty in elderly people. CMAJ 2005; 173: 489–95.
Jones DM, Song X, Mitnitski AB, Rockwood K. Evaluation of a frailty index based on a Comprehensive Geriatric Assessment in a population based study of elderly Canadians. Aging Clin Exp Res 2005; 17: 465–71.
Mitnitski AB, Rockwood K. Decrease in the relative heterogeneity of health with age: A cross-national comparison. Mech Ageing Dev 2006; 127: 70–2.
Goggins WB, Woo J, Sham A, Ho HC. Frailty index as a measure of biological age in a Chinese population. J Gerontol A Biol Sci Med Sci 2005; 60: 1046–51.
Woo J, Goggins W, Sham A, Ho SC. Social determinants of frailty. Gerontology 2005; 51: 402–8.
Rockwood K. Frailty and its definition: a worthy challenge. J Am Geriatr Soc 2005; 53: 1069–70.
Fisher AL. Just what defines frailty? J Am Geriatr Soc 2005; 53: 2229–30.
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Song, X., MacKnight, C., Latta, R. et al. Frailty and survival of rural and urban seniors: results from the Canadian Study of Health and Aging. Aging Clin Exp Res 19, 145–153 (2007). https://doi.org/10.1007/BF03324681
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DOI: https://doi.org/10.1007/BF03324681