OCTO Twin
Origins of Variance in the Old-Old
Life span
General presentation
Boo Johansson
National Institute on Aging: AG 08861
Acknowledgements
• Funded in part by Grant R13AG030995-01A1
from the National Institute on Aging
• The views expressed in written conference
materials or publications and by speakers and
moderators do not necessarily reflect the official
policies of the Department of Health and Human
Services; nor does mention by trade names,
commercial practices, or organizations imply
endorsement by the U.S. Government.
Friday Harbor
Psychometrics
Major Swedish Longitudinal Aging Studies
..at that time
- population-based
- longitudinal design
- possible to conduct
- informative
H70 (70+), OCTO (84+), …. SATSA (55+) ….??
1988
Background for the OCTO Twin Study
- Observations of substantial individual differences in rate
and patterns of aging
- Understanding the origins of this variability is of
fundamental importance – What are the relative
contributions of genetic and environmental influences?
- Limited information about the oldest old age segement in
the above respect
The planning for a Twin Study of the
started ~ 20 years ago (1988)
H70,OCTO, SATSA
..the missing ‘piece’
OCTO Twin
Old-Old (80 +)
OCTO Twin - OVERALL AIM
• To estimate the relative contributions of
environmental and genetic influences to
the variability in health and biobehavioral
functioning …..
• at each measurement occasion as well as to
longitudinal change and continuity during interoccasion intervals
..in a life span genetic and
environmental influence
perspective
An individual difference approach
focus on variance among individuals within a population
------------------------
Directs our attention to the origins of variability
within an age group
-----------------------
Thus,
we become compelled to search for the fundamental
sources for observed differences
in a specific phenotype
The prototypic twin design
Monozygotic (MZ) pairs
and
Dizygotic (like-sex) pairs
• compared with respect to
intra-pair similarities
MZ - monozygotic twins share 100% of all genetic influences
Same birthday
Same parents
DZ - dizygotic twins share on average 50% of genetic influences
The OCTO Twin Design
Wave 1
Wave 2
Wave 3
Wave 4
Wave 5
5 measurement occasions, 2-years apart
1991 
1993
March
May
April
March
March





1994
March

1996
March
 1995
 1998
March


1997
2000
March
 1999

2002
March
Domains at focus
Health and functional capacity
Cognitive functioning
Personality and personal control
Psychological well-being
Interpersonal functioning
Using largely the same measures as in reference studies (H70, OCTO, SATSA
Health and functional capacity
- Self-rated health
- Self-reported medical history (”checklist”)
- Sensory (Vision, hearing)
- PB, Pulse, BMI
- Functional tests of balance and gait
- Grip strength, lung capacity
- Contacts with the health care system (district
nurse, physicans, and hospital)
- Information from medical (ICD-10 coded) and dental
records
- Medications (ATC –codes)
- Blood chemistry panel
Memory and Cognition
- Cog.status – MMSE, Clock Test, Coin Test
- Inductive reasoning – figure logic
- Psychomotor speed - Psif, Digit-Symbol
- Visuospatial ability – Koh’s Block
- Primary memory – Digit Span
- Semantic memory – Synonyms - Information
- Episodic memory – Prose, MIR, Thurstone Picture memory
Dementia work-up
individuals suspected for dementia
- Review of memory and cognitive tests
- Informant neuropsychological interview
- Review of medical records and supplement information
- A consensus diagnosis conference
(DSM, ICD, NINCDS-ADRA, NINDS-AIREN, etc)
Personality and Personal Control
- Eysenck Personality Inventory (EPI)
- Global Locus of Control
- Heatlh Locus of Control
Psychological Well-being
- Life Satisfaction Scale (LSI-Z)
- Depressive symptoms scale (CES-D)
- Open ended questions, e.g. significant life events
Interpersonal functioning
- Social networks
- Contact frequencies
- Confidants
- Loneliness
Functional capacity
- ADL Apparatus Test
- ADL and IADL Scales (Self and RN ratings)
- Need for help in ADL/IADL
- Home help/institutional care
- Technical aids, mobility, hearing, vision
e
s
t
i
n
g
s
e
s
s
i
o
n
Supplement information
Twin Registry
Ratings by RNs’ and PD
Medical records
Dental records
Death certificates
Dementia work-up
Autopsy/neuropathology
Procedure
- In-person/individual examinations in place of residence
across the country
- by trained and supervised RNs
- using a broad-based biobehavioral battery
Members of a twin pair never investigated by same RN
to avoid expectation bias.
The RNs’ blind to zygosity.
The OCTO Twin Sample
• Twins in complete pairs, 80 years and older at
baseline (< 1913)
• MZ (monozygotic) twin pairs (N=149) and samesex DZ (dizygotic) twin pairs (N=202)
• All survivors followed longitudinally across
5 waves, 2-years apart
Population selection in OCTO Twin:
Number of tested individuals and pairs across waves (8y)
W1
W2
W3
W4
W5
MZ DZ
MZ DZ
MZ DZ
MZ DZ
MZ DZ
65 79
43 43
20 23
Pairs
149 202 98 137
Men
Women
56 61
93 141
38 40
60 97
22 23
43 56
12 10
32 33
5 4
15 19
Total
351
235
144
86
43
MZ %
42,5
41,7
45,1
50,0
46,5
298 404
235 333
178 252
142 173
100 122
Men
Women
112 122
186 282
90 101
145 232
65 77
113 175
47 43
95 130
31 26
69 96
Total
702 (704)
568
430
315
MZ %
42,5
41,4
41,4
45,1
Individuals
222
42,5
R-rate > 90%
Ongoing Swedish Twin Studies
on Aging
• SATSA
• OCTO Twin
• Gender
• Harmony
Boo Johansson