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Health inequalities and dementia
Tom Russ
Alzheimer Scotland Dementia Research Centre & Division of PsychiatryUniversity of Edinburgh
28th January 2015
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Dementia
Dementia describes a syndrome of cognitive & functional decline
Often accompanied by behavioural and psychological symptoms
The commonest cause is Alzheimer disease (50-75%)
Approximately one in 20 older adults is a↵ected
Growing numbers; falling prevalence??
850,000 people in the UK; 36 million worldwide
If dementia were a country it would have a G20 seat
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 3 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Public health importance
Financial cost greater than cardiovascular disease and cancer
Personal cost to those a↵ected unmeasurable
Approximately half of people are not diagnosed
Post-diagnostic support now guaranteed in Scotland
Early treatment can a↵ect outcome, including preservingfunction and keeping people at home for as long as possible
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 4 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Mysterious dementia
Alois Alzheimer described the first case in 1906
There has been over two decades of intensive research. . .
. . . and there are still no disease-modifying treatments
There is an urgent need to understand dementia aetiology
Delaying or preventing onset would have substantial e↵ects
Two health inequalities: unscheduled admissions and geography
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 5 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Dementia in the general hospital
People with dementia are often admitted to hospital
6% of people with dementia are in hospital now(vs 0.6% of the general older population)
25% of general hospital inpatients have cognitive impairment
Only half will have been given a diagnosis
People with dementia are vulnerable in hospital
Unscheduled admissions should be avoided, where possible
But. . . what factors put someone at risk of admission?
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 6 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Scottish Dementia Research Interest Register
People from across Scotland
Diagnosed with dementia (and carers)
Who have expressed an interest in research
Demographic, cognitive, functional, and behavioural measures
Consent to linkage to electronic health records
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 7 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Electronic health records
Scottish Morbidity Records 01 and 04
All general and psychiatric hospital admissions in Scotland
Community Health Index (chi) number is a unique identifier:
28 01 15 1234Allows linkage of all health data pertaining to this individual
e.g. identifying who has been admitted to hospital and when
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 8 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Data recorded
Addenbrookes Clinical Examination — Revised
Instrumental Activities of Daily Living scale
Personal Self-Maintenance scales
Neuropsychiatric Inventory including Carer Distress
Clinical Dementia Rating scale
Details of illnesses and prescribed medications
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 9 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Survival analysis
www.unc.edu
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 10 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Survival analysis
www.unc.edu
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 11 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
SDRIR sample
N = 730
47.8% female
Mean (SD) age 76.3 (8.2)
Range 50 to 94 years
Mean follow up 1.2 years
Range 2 days to 3.3 years
37.5% admitted
Various reasons
Dementia recorded 53.3%
Russ TC et al. (2015) Prediction of general hospital admission in people with dementia: cohort study. Brit J Psychiatry
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 12 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Predictors of admission
Male (HR; 95% CI: 1.32, 1.04–1.68)
Non-AD, non-vascular dementia (1.67, 1.09–2.56)
Comorbidity (1.28, 1.00–1.65)
Physical Self-Maintenance scale (1.18, 1.04–1.33)
Neuropsychiatric Inventory (1.22, 1.09–1.37)
NPI carer distress (1.14, 1.02–1.28)
Russ TC et al. (2015) Prediction of general hospital admission in people with dementia: cohort study. Brit J Psychiatry
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 13 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Neuropsychiatric symptoms predict admission
NPI score was the onlyindependent predictor
One standard deviationincrease in score increasedrisk of admission by 21%
Risk highest in highest levelsof distress
Agitation may be the mostimportant symptom
Time (days)10957303650
Cum
ulat
ive
Surv
ival
1.0
0.8
0.6
0.4
0.2
0.0
>141-140
NPI score
Page 1
Russ TC et al. (2015) Prediction of general hospital admission in people with dementia: cohort study. Brit J Psychiatry
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 14 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Interim conclusions
Dementia is common and important
Many people with dementia are admitted to hospital
Neuropsychiatric symptoms might increase risk of admission
Can we reduce these symptoms and thus risk of admission?
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 15 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Geographical variation in disease
The “Scottish” e↵ect
Cardiovascular disease
Leukaemia
Multiple sclerosis
Schizophrenia
Dementia?
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 16 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Geographical variation in dementia
‘Quantitative integrations of the literature’I e.g. eurodem, eurocode
Methodological di�culties in comparing studiesI diagnostic criteriaI methodologyI population studied
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 17 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Geographical variation in dementia
Evidence at most scales of geographical variation in dementia
Wide variation in quality of studies
Rural living is associated with an increased risk of AD
Small area research (most informative) is most scarce
Geographical variation may help identify risk/protective factors
Russ TC et al. (2012) Geographical variation in dementia: systematic review and meta-analysis. Int J Epidemiol 41: 1012-32.
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 19 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Association between rurality and dementia
Prevalence:OR 1.11, 90% CI 0.79-1.57
Incidence: 1.20, 0.84-1.71
Stronger for AD, particularlyearly life exposure:
I prevalence 2.22, 1.19-4.16I incidence 1.64, 1.08-2.50
Definition of rurality
Study
Ogunniyi et al (2000)Ogunniyi et al (2000)Lin et al (1998)Zhang et al (2006)Jean et al (1996)
Overall
OR (90% CI)
1.57 (0.44−5.56)2.49 (1.21−5.12)1.17 (0.74−1.85)1.50 (1.29−1.75)1.52 (1.21−1.90)
1.64 (1.08−2.50)
0 1 2 3
Odds ratio
Russ TC et al. (2012) Geographical variation in dementia: systematic review and meta-analysis. Int J Epidemiol 41: 1012-32.
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 20 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Media coverage
“People who grow up in countryside ‘twice as likely to developAlzheimer’s”
“Being raised in the countryside ‘doubles Alzheimer’s risk’ butresearchers have no idea why”
“Alzheimer’s: ‘Growing up in rural area doubles risk”’
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 21 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Media coverage
“People who grew up in rural areas ‘at twice the risk of Alzheimer’s’. . .Alzheimer’s experts have urged caution about the findings
and say there is no compelling reason to flee the countryside
for urban life”!
WebMD UK Health News“Health information you can trust”
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 22 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Small area studies of dementia
Frecker (1991) J Epidemiol Commun H. Whalley et al. (1995) Brit J Psych.
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 23 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Questions
Does the prevalence and incidence of dementia vary by place?
Is such variation real or artifactual?
What factors might be associated with this variation?
Are any of them potentially modifiable?
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 24 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Swedish Twin Registry
Established in 1961
Comprehensive twin register
1886 births onwards
Questionnaire data collected
All dementia cases identified
Gatz, M. et al. (2005) Neurobiol Aging 26: 439–47.
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 26 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
1932 Scottish Mental Survey
Intelligence test of all11-year-old children (87,498)
Repeated in 1947
Unique in the world
Moray House Test
Findings published in 1933
S.C.R.E. (1933) The intelligence of Scottish children: a national survey of an age-group. London: University of London Press.
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 27 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
1932 Scottish Mental Survey: follow up
Ledgers discovered by accident
Local follow-up since 1997I
www.lothianbirthcohort.ed.ac.uk
Iwww.disconnectedmind.ed.ac.uk
Iwww.abdn.ac.uk/aberdeen-birth-cohort
They form a narrow age cohort
Record linkage of entire cohort by the Information and StatisticsDivision of NHS National Services Scotland (linkage rate 44%)
Hospital discharge data
Mortality data
Greater Glasgow & Clyde Nursing Homes Medical PracticeDeary, Whalley & Starr (2009) A lifetime of intelligence. Washington: American Psychological Association.Deary, Gow, Pattie & Starr (2012) Cohort Profile: The Lothian Birth Cohorts of 1921 and 1936. Int J Epi 41: 1576–84.
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 28 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Bayesian disease mapping
Many statistical methods assume independence of observations
Tobler’s first law of geography: close things are more similarthan things which are further apart
Smooths out random variation in disease prevalence/incidence
Very computer intensive – longest model ran for 10 days!
Result is relative e↵ect for each small area
Tobler (1970) Econ Geogr 46: 234–40.
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 29 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Oesophageal cancer in Germany
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Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 30 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Swedish study
Male and female Swedish twins analysed separately
Total sample size 27,680 (50% female; 25% monozygotic)
Mean (sd; range) age:I Men: 78.2 years (8.2; 41–103)I Women: 80.2 years (8.1; 28–110)
993 dementia cases
Located by 5-digit zipcode of adult residence(mapped by 3-digit zipcode; N = 568)
Russ et al. (2015) Geographical variation in dementia examining the role of environmental factors in Sweden & Scotland. Epidemiology.
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 32 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Swedish twins — genetic e↵ects removed
Russ et al. (2015) Geographical variation in dementia examining the role of environmental factors in Sweden & Scotland. Epidemiology.
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 33 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Scottish study
Male and female participants analysed separately
Total sample size 37,597 (48.7% female; all born in 1921)
3605 dementia cases
Located at age 11 by county of school attended (N=38)
Located in adulthood by postcode sector (N = 953)
7854 missing adult location
Russ et al. (2015) Geographical variation in dementia examining the role of environmental factors in Sweden & Scotland. Epidemiology.
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 35 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Scotland: childhood location
Russ et al. (2015) Geographical variation in dementia examining the role of environmental factors in Sweden & Scotland. Epidemiology.
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 36 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Scotland: adult location
Russ et al. (2015) Geographical variation in dementia examining the role of environmental factors in Sweden & Scotland. Epidemiology.
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 37 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Hypotheses redux
Both studies support geographical variation of dementia rates
This was not completely explained by genetic/familial factors
Something(s) acting in adolescence or later?
We can speculate whether there is an e↵ect of latitude
Russ et al. (2015) Geographical variation in dementia examining the role of environmental factors in Sweden & Scotland. Epidemiology.
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 38 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Some speculations on mechanisms
Both studies seem to point to a north-south e↵ect so might there bea risk or protective factor related to latitude?
Selenium may have a role in dementia (Loef et al., 2011) andconcentrations vary with latitude in Sweden (low in the north)
Lower vitamin D levels have been linked to poorer cognition andincreased risk of AD (Balion et al., 2012; Littlejohns et al., 2014)
Previous work suggested the importance of proximity to mining;the majority of mines in Sweden are in the north of the country.
Balion (2012) Neurology 79: 1397–405; Littlejohns (2014) Neurology 83: 920–8; Loef (2011) J Alzheimers Dis 26: 81–104.
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 39 / 42
Dementia Unscheduled admissions Geographical clustering Disease mapping Sweden & Scotland Discussion
Concluding remarks
Dementia is a major and growing public health concern
Neuropsychiatric symptoms relate to risk of hospital admission
Dementia rates do seem to vary with geographical location
Should resources be redirected to areas with increased need?
If environmental factor(s) are responsible, what are they?
Can we optimise them in everyone and halve dementia rates?
Tom Russ (University of Edinburgh) Twitter: @AlzScotDRC 28th January 2015 41 / 42
Acknowledgements
Margaret Gatz, Nancy L. Pedersen, Jean Hannah, Grant Wyper,G. David Batty, Ian J. Deary & John M. Starr
TR was supported by Alzheimer Scotland and the Scottish Dementia ClinicalResearch Network during the course of this work. He is now employed by the
University of Edinburgh and NHS Lothian. He is a member of both theAlzheimer Scotland Dementia Research Centre funded by Alzheimer Scotlandand the University of Edinburgh Centre for Cognitive Ageing and Cognitive
Epidemiology, part of the cross council Lifelong Health and WellbeingInitiative (G0700704/84698). Funding from the BBSRC, EPSRC, ESRC and
MRC is gratefully acknowledged.
www.alzscotdrc.ed.ac.uk
@AlzScotDRC