Dementia - what can Public Health do to respond to the scope for Prevention? - Olga Cleary IPH, Open, Conference, Belfast, Northern, Ireland, Dublin, Titanic, October, 2014, Public, Health

1. Dementia –what role
for prevention?
Institute of Public Health
Alzheimer’s Society of Ireland
Olga Cleary PhD
IPH Open Conference 14th October 2014

2. Overview
• Prevalence
• Impact
• Evidence
• Terminology
• Dementia protective and risk factors
• Population attributable risk for
modifiable factors in Ireland
• Population approach to dementia
prevention
• Process – embedding dementia
prevention in research, policy and
practice
Why?
What?
How?

3. Emergence of
Neurodegenerative disorders
Epidemiological transition is underway as a result
of demographic ageing, characterised by an
increase in neurodegenerative disorders which will
gradually come to replace the current burden of
chronic degenerative disorders as the primary
cause of morbidity and mortality in the
21st century!

4. Dementia prevalence estimates
• Worldwide - 44 million living with dementia (ADI, 2013)
• Western Europe - 7 million living with dementia in
2010 (Prince, 2009)
• Ireland – 47,744 living with dementia in 2011 (Cahill, and
Pierce 2013).
• Expected to double every 20 years
• By 2031 (if current assumptions hold) estimated to
be 90,000 people living with dementia in Ireland

5. Impact
Care setting Proportion of people
with dementia
Community 63%
Residential Long-stay Care 34%
Acute Care 2%
Psychiatric Care 1%
All 100%
Connolly et al, 2014
• €40,500 - average cost per person with dementia per annum
• €1.69 billion in 2010
Lowin et al, 2001; Trepel 2012
• At the individual level, the economic burden of dementia ranks higher
than stroke, heart disease and cancer combined - allocated resources
substantially lower than each of these individual disease groups

6. Question..?
Resource allocation………….
Management
Treatment
Diagnosis
Prevention

7. Terminology

8. Alcohol
Physical
inactivity
Coron. heart dis.
Chron. kidney disease
Diabetes
Cholesterol
Smoking
Midlife obesity
High cognitive activity
Depressed mood
Healthy diet
Midlife hypertension
In-MINDD
dementia risk
model

9. Modelling modifiable dementia risk in Ireland
Methodology
- Lancet Neurology
Barnes and Yaffe (2011) and Norton et al (2014)
Systematic reviews & meta-analyses – potentially modifiable factors associated with
increase in Alzheimer’s Disease and cognitive decline (Daviglus et al 2010; McGuiness et al
2009; Profenno 2010)
7 Factors with most consistent evidence:
• Diabetes Mellitus
• Current smoking
• Depression
• Low educational attainment
• Physical inactivity
• Obesity
• Hypertension
• Poor diet (high sat fat/low veg)
Calculated PAR based on RRs from Cochrane reviews/meta-analyses
- Assuming causal relationship between risk factor and disease, PAR is number of cases of a
disease in a population attributable to the risk factor.
Irish prevalence estimates taken from Cahill and Pierce (2013) applying EuroCoDe
dementia prevalence to 2011 census data

10. Population attributable risk and estimated
number of attributable cases in Ireland 2011.
Risk factors TILDA
weighted
prevalence
%
Relative Risk
95% CI’s
PAR
95% CI’s
Number of attributable cases
in 2011 (47,744)
95% CIs
Low
education
38% 1.59 (1.35-1.86) 18.3% (11.7-24.6) 8,737 (5,586-11,745)
Obesity 34% 1.6 (1.34-1.92) 16.9% (10.4-23.8) 8,069 (4,965-11,363)
High Blood
32% 1.61 (1.16-2.24) 16.5% (4.9-28.7) 7,878 (2,339-13,703)
Pressure
Physical
Inactivity
32% 1.82 (1.19-2.78) 20.8% (5.7-36.3) 9,930 (2,721-17,331)
Smoking 20% 1.59 (1.15-2.2) 10.6% (2.9-19.3) 5,060 (1,385-9,215)
Diabetes 8% 1.46 (1.2-1.77) 3.5% (1.6-5.8) 1,671 (764-2,769)
Depression 5% 1.65 (1.42-1.92) 3.1% (2.1-4.4) 1,480 (1,003-2,101)
COMBINED 62.5% (33.6-81.0) 29,840 (16,042-38,673)

11. Strengths and limitations
• Estimates based on best available evidence
• PAR estimates assume a causal relationship between risk factor
and dementia outcome, however dementia is multi-factorial
and it is not known if removal/reduction of single risk factors
will lower incidence
• Relative risks while robust, are not based on Irish data
• Risk relations are taken at particular ages and it was not
possible to model the dynamic interplay of risk factors over the
lifecycle.
• Have not adjusted for the non-independence of risk factors
• May be other important factors influencing risk not accounted
for in analyses.
• Community dwelling population in TILDA (excludes
institutionalised and dementia diagnosed)

12. Implications of study findings
• Reductions in prevalence of key modifiable risk factors for dementia is
likely to lead to a reduction in the onset and prevalence of dementia at
a population level in Ireland.
• Estimated combined PAR for Ireland (independent) = 62.5%
• Pooled methods, accounting for non-independence of the risk factors
examined, estimated a much more conservative effect (Norton, 2014).
• Estimated combined PAR for Europe (independent) = 52.7%
• Estimated pooled combined PAR for Europe (non-independence) =
30.6%
• True effect in modifying risk factors remains unknown and we require
further studies to fully investigate this, but it is likely to lie in the
magnitude of 30-60% in Ireland.
• This equates to 14,243 – 28,468 people living with dementia at any one
time in Ireland.
• €576,841,500 per annum cost of dementia patients

13. Developing a population health approach to
dementia prevention
• Need to mitigate burden of dementia
• Moving from:
• Treatment and management to prevention
• Clinical concepts to public health
• Individual focus to population health focus (WHO, 2012)
• Research to policy and practice
Older people with better vascular health, who have been more
physically, mentally and socially active, whose diet is lower in saturated
fats and higher in vegetable and fruit consumption, who don’t smoke
and who drink alcohol in moderation are significantly less likely on
average to develop dementia.

14. Development of a public health approach to dementia
prevention that is strategic, evidence-based and
comprehensive
(McDaid and McAvoy, 2012 - National Dementia Strategy submission)
• Potential for public health interventions
• Synergies in prevention
• Embed dementia prevention in policy and practice
• Enhance current DoH and HSE strategies and programmes
• Afford priority to counteracting risk factors for CVD
• Appropriate intervention for CVD risk factors and
preventative health practices in primary care
• Concept of brain health emerging as an important
paradigm on the neuroscience and public health agenda
• Social patterning and early years intervention

15. Thank You!
Contact:
olga.cleary@publichealth.ie
Acknowledgements:
Helen McAvoy and Owen Metcalf (Institute of Public Health)
Margaret Crean, Emer Begley and Grainne McGettrick (Alzheimer’s Society
of Ireland)
TILDA team