The nature of behavioural correlates of healthy ageing: a twin study of lifestyle in mid to late life.
BACKGROUND
With the greying of the industrialized world has come increased interest in identifying the modifiable lifestyle factors that promote healthy and successful ageing. Whereas many of the behavioural correlates of late-life morbidity and mortality have been identified, relatively little is known about the origins of individual differences in these factors.


METHODS
A sample of 12,714 twins, including both members of 3806 pairs of known zygosity, ascertained through the Danish Twin Registry and aged 40 to 80 years, completed a self-report assessment of six lifestyle factors associated with ageing: smoking, drinking, diet and physical, social and intellectual activities. Standard biometric methods were used to analyse the twin data and determine the extent to which individual differences in each of the lifestyle factors are heritable.


RESULTS
For each of the six lifestyle factors, the estimate of heritability ranged from 32% (95% CI: 19-42%) for the diet scale to 69% (62-72%) for the smoking measure. Biometric estimates of the contribution of the twins' common rearing environment were uniformly small (≤6%). There was little evidence that standardized biometric estimates varied by gender or age.


CONCLUSIONS
Individuals likely construct lifestyles in part to complement and reinforce underlying genetically influenced dispositions and talents. The heritable nature of lifestyle factors implies that the behavioural and genetic contributors to ageing processes are not necessarily conceptually distinct but rather reflect the complexity of gene-environment interplay in ageing.
Department of Psychology, University of Minnesota, Minneapolis, MN USA, Department of Epidemiology, Institute of Public Health, University of Southern Denmark, Odense, Denmark, The Danish Twin Registry and Danish Ageing Research Centre, Institute of Public Health, University of Southern Denmark, Odense, Denmark Department of Clinical Genetics and Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark Department of Psychology, University of Minnesota, Minneapolis, MN USA, Department of Epidemiology, Institute of Public Health, University of Southern Denmark, Odense, Denmark, The Danish Twin Registry and Danish Ageing Research Centre, Institute of Public Health, University of Southern Denmark, Odense, Denmark Department of Clinical Genetics and Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark mcgue001@umn.edu.
Matt
M
McGue
Department of Psychology, University of Minnesota, Minneapolis, MN USA, Department of Epidemiology, Institute of Public Health, University of Southern Denmark, Odense, Denmark, The Danish Twin Registry and Danish Ageing Research Centre, Institute of Public Health, University of Southern Denmark, Odense, Denmark Department of Clinical Genetics and Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark Department of Psychology, University of Minnesota, Minneapolis, MN USA, Department of Epidemiology, Institute of Public Health, University of Southern Denmark, Odense, Denmark, The Danish Twin Registry and Danish Ageing Research Centre, Institute of Public Health, University of Southern Denmark, Odense, Denmark Department of Clinical Genetics and Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark.
Axel
A
Skytthe
Department of Psychology, University of Minnesota, Minneapolis, MN USA, Department of Epidemiology, Institute of Public Health, University of Southern Denmark, Odense, Denmark, The Danish Twin Registry and Danish Ageing Research Centre, Institute of Public Health, University of Southern Denmark, Odense, Denmark Department of Clinical Genetics and Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark Department of Psychology, University of Minnesota, Minneapolis, MN USA, Department of Epidemiology, Institute of Public Health, University of Southern Denmark, Odense, Denmark, The Danish Twin Registry and Danish Ageing Research Centre, Institute of Public Health, University of Southern Denmark, Odense, Denmark Department of Clinical Genetics and Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark Department of Psychology, University of Minnesota, Minneapolis, MN USA, Department of Epidemiology, Institute of Public Health, University of Southern Denmark, Odense, Denmark, The Danish Twin Registry and Danish Ageing Research Centre, Institute of Public Health, University of Southern Denmark, Odense, Denmark Department of Clinical Genetics and Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark.
Kaare
K
Christensen
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000428:Alcohol Drinking / Q000453:epidemiology; D003718:Denmark / Q000453:epidemiology; D004032:Diet; D015444:Exercise; D015438:Health Behavior; D006801:Humans; D007398:Interpersonal Relations; D008019:Life Style; D008603:Mental Health; D008875:Middle Aged; D012907:Smoking / Q000453:epidemiology; D014429:Twins, Dizygotic / Q000523:psychology / Q000706:statistics & numerical data*; D014430:Twins, Monozygotic / Q000523:psychology / Q000706:statistics & numerical data*
heritability; lifestyle and ageing; successful ageing; twin study