Genetic Factors and Susceptibility to Falls in Older Women
Genetic Factors and Susceptibility to Falls in Older Women
Objectives: To determine whether genetic influences account for individual differences in susceptibility to falls in older women.
Design: Prospective twin cohort study.
Setting: Research laboratory and residential environment.
Participants: Ninety-nine monozygotic (MZ) and 114 dizygotic (DZ) female twin pairs aged 63 to 76 from the Finnish Twin Cohort study.
Measurements: The participants recorded their falls on a calendar for an average ± standard deviation of 344 ± 41 days. Reported falls were verified via telephone interview, and circumstances, causes, and consequences of the fall were asked about.
Results: The total number of falls was 434, of which 188 were injurious; 91 participants had two or more falls. Casewise concordance was 0.61 (95% confidence interval (CI) = 5 0.49-0.72) for MZ twins and 0.49 (95% CI = 0.37-0.62) for DZ twins for at least one fall, 0.38 (95% CI = 0.23-0.53) for MZ and 0.33 (95% CI = 0.17-0.50) for DZ twins for at least one injurious fall, and 0.43 (95% CI = 0.26-0.60) for MZ and 0.36 (95% CI = 0.17-0.55) for DZ twins for recurrent falls. On average, the proportion of familial influences accounting for the individual differences in susceptibility to at least one fall was 30% and to recurrent falls was 40%; nongenetic familial and nonfamilial factors alone accounted for susceptibility to at least one injurious fall.
Conclusion: In community-dwelling older women, familial factors underlie the risk of falling but not the risk of injurious falls.
In older people, falls are associated with risk for onset of disability and institutionalization, contributing thereby to the burden on the healthcare system. One-third of persons aged 65 and older experience at least one fall annually, and thereafter, fall risk increases. Falling in older people is usually a result of functional limitations caused by factors such as arthritis, poor vision, impaired balance, and poor muscle strength in combination with challenges connected with the environment and with the activities performed. In younger and healthier old people, falls are more often related to environmental and behavioral risk factors than they are in older and frailer old people.
Although falls in older people are widely studied, thus far estimates of the genetic contribution to susceptibility to falls are lacking. A large-scale Finnish twin study failed to find a significant genetic contribution to fall-related osteoporotic fractures. It may be inferred from this that, in older people, factors other than familial factors may predominantly determine causes of osteoporotic fractures such as falling, although, because genetic influences are known to contribute to fall-related factors such as postural balance, muscle function, cognitive abilities, and physical activity, genetics may contribute to fall risk as well. Knowledge of the role of genetics in fall susceptibility in older people is useful in designing effective fall-prevention programs.
The aim of the present study was to examine the proportion of genetic factors accounting for individual differences in susceptibility to falls, with and without injury, over a 12-month follow-up in 63-to 76-year-old women.
Objectives: To determine whether genetic influences account for individual differences in susceptibility to falls in older women.
Design: Prospective twin cohort study.
Setting: Research laboratory and residential environment.
Participants: Ninety-nine monozygotic (MZ) and 114 dizygotic (DZ) female twin pairs aged 63 to 76 from the Finnish Twin Cohort study.
Measurements: The participants recorded their falls on a calendar for an average ± standard deviation of 344 ± 41 days. Reported falls were verified via telephone interview, and circumstances, causes, and consequences of the fall were asked about.
Results: The total number of falls was 434, of which 188 were injurious; 91 participants had two or more falls. Casewise concordance was 0.61 (95% confidence interval (CI) = 5 0.49-0.72) for MZ twins and 0.49 (95% CI = 0.37-0.62) for DZ twins for at least one fall, 0.38 (95% CI = 0.23-0.53) for MZ and 0.33 (95% CI = 0.17-0.50) for DZ twins for at least one injurious fall, and 0.43 (95% CI = 0.26-0.60) for MZ and 0.36 (95% CI = 0.17-0.55) for DZ twins for recurrent falls. On average, the proportion of familial influences accounting for the individual differences in susceptibility to at least one fall was 30% and to recurrent falls was 40%; nongenetic familial and nonfamilial factors alone accounted for susceptibility to at least one injurious fall.
Conclusion: In community-dwelling older women, familial factors underlie the risk of falling but not the risk of injurious falls.
In older people, falls are associated with risk for onset of disability and institutionalization, contributing thereby to the burden on the healthcare system. One-third of persons aged 65 and older experience at least one fall annually, and thereafter, fall risk increases. Falling in older people is usually a result of functional limitations caused by factors such as arthritis, poor vision, impaired balance, and poor muscle strength in combination with challenges connected with the environment and with the activities performed. In younger and healthier old people, falls are more often related to environmental and behavioral risk factors than they are in older and frailer old people.
Although falls in older people are widely studied, thus far estimates of the genetic contribution to susceptibility to falls are lacking. A large-scale Finnish twin study failed to find a significant genetic contribution to fall-related osteoporotic fractures. It may be inferred from this that, in older people, factors other than familial factors may predominantly determine causes of osteoporotic fractures such as falling, although, because genetic influences are known to contribute to fall-related factors such as postural balance, muscle function, cognitive abilities, and physical activity, genetics may contribute to fall risk as well. Knowledge of the role of genetics in fall susceptibility in older people is useful in designing effective fall-prevention programs.
The aim of the present study was to examine the proportion of genetic factors accounting for individual differences in susceptibility to falls, with and without injury, over a 12-month follow-up in 63-to 76-year-old women.
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