The Northern Ireland Longitudinal Study:
An Outline of the Research Potential for
Government Users
NILS Research Support Unit:
Fiona Johnston
Michael Rosato
Dr Gemma Catney
Seminar Outline
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Introduction & Background to the Northern Ireland Longitudinal
Study (NILS)
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Role of the NILS Research Support Unit
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Research Projects: Policy Relevant Themes

Policy Outreach & Government Users

Research Findings: Implications for Policy

Introduction & Background to the Northern Ireland Longitudinal
Study (NILS)

Role of the NILS Research Support Unit

Research Projects: Policy Relevant Themes

Policy Outreach & Government Users

Research Findings: Implications for Policy
Introduction to the NILS and NIMS
Northern Ireland Longitudinal Study (NILS) – 28% representative sample of
NI population (c. 500,000), based on health card registrations, linked to:
1.
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2001 Census returns
vital events (births, deaths and marriages)
demographic & migration events AND
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distinct Health & Care datasets
2.
Northern Ireland Mortality Study (NIMS) - enumerated population at Census
Day (c.1.6 million), linked to:
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2001 Census returns
subsequently registered mortality data
Both NILS and NIMS linked to contextual and area-based data:
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capital value of houses and property attributes
geographical indicators
settlement classifications
deprivation measures
Structure of the NILS
Datasets Routinely Linked
Census Dataset 2001
Variables include:
Age, sex and marital status
Religion and community background
Family, household or communal type
Housing, including tenure, rooms and amenities
Country of birth, ethnicity
Educational qualifications
Economic activity, occupation and social class
Migration (between 2000 and 2001)
Limiting, long-term illness, self-reported general
health, caregiving
Travel to work
LPS Property Data 2010
Capital and rating value (based on 2005 valuation
exercise)
Variables include:
- Household characteristics (no. of rooms,
property type, floor space, central heating) and
valuation
- Estimated capital value
GRO Vital Events Datasets 1997-2007
- New births into the sample
- Births to sample mothers and fathers
- Stillbirths to sample mothers
- Infant mortality of children of sample mothers
and fathers
- Deaths of sample members 2001-2007
- Marriages 2004-2006
- Widow(er)hoods 2004-2006
Health Card Registration Datasets 2001-2010
- Demographic data: age, status and location
- Migration events:
immigrants added to the sample
emigration of sample members
re-entry of sample members to NI
migration within NI
Background to the NILS and NIMS
1. Research-Driven
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cross-sectional studies: no information on change over time
other UK LS
health and socio-demographic profile of NI
2. Legislation
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confidentiality protected, and managed, by NISRA under census
legislation
NISRA have consulted the following about NILS:

Information Commissioner for Northern Ireland

Office of Research Ethics

Health and Social Care Privacy Advisory Committee
3. Funding
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infrastructure funded by the Health and Social Care R&D Division
of the PHA and NISRA
research support function funded by ESRC and NI Government
(OFMDFM)
NILS Research Support Unit
Background:
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Based: Centre for Public Health (QUB) and NISRA HQ (McAuley House)
Support: 2 full-time and 1 half-time Research Support Officers
Set-up: April 2009
Remit:
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raise awareness of the NILS research potential;
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assist with development of research ideas and projects;
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facilitate access to NILS data;
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training & advice in use and analysis of NILS datasets;
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promote policy relevance; and
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enhance NILS research capacity incl: specific duty to assist government
researchers and to undertake exemplar public policy research.
Research Support:
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raise awareness of the NILS research potential;
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development and feasibility of research ideas and projects: big and
small!
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gaining research approval & the application process;
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data preparation/analysis and interpretation of results (incl. training
on software); and
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dissemination and publishing of results e.g. reports and papers,
web-based publications and presentations at seminars,
conferences.
Access:
NILS data are sensitive and access is highly controlled:
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researchers can access data only within a ‘secure setting’ (NILSRSU office at McAuley House); arrangements can be made to run
analyses remotely;
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researchers must sign and abide by user licenses & security policies;
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disclosure control thresholds in place to protect confidentiality of the
data: no tabulated cell counts less than 10 are released; and
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all outputs must be cleared by NISRA staff.
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Introduction & Background to the Northern Ireland Longitudinal
Study (NILS)

Role of the NILS Research Support Unit

Research Projects: Policy Relevant Themes

Policy Outreach & Government Users

Research Findings: Implications for Policy
Health & Mortality
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Temperature-related mortality and housing (DSD)
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Socio-demographic and area correlates of suicides
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Distribution of cancer deaths in Northern Ireland by population and
household type (NI Cancer Registry)
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Variations in alcohol related deaths in Northern Ireland
Demographic Trends
 Fertility in the short-run in Northern Ireland?
 Fertility levels, and future school populations, by area of
residence and community background (DENI)
 Lone mothers at time of birth: who are they?
 Describing and modelling internal migration
 Vital events: Standard Table Outputs (DMB)
 Deprivation & ill-health a comparison of Scotland and NI
Education, Employment & Income
 Educational attainment and mobility (DEL)
 Unemployment and permanent sickness in NI
 Pervasive area poverty: modelled household income (OFMDFM)
 House value as an indicator of cumulative wealth in older people
Area-Based Analysis
 Rural aspects of health
 Population movement and the spatial distribution of socio-economic and
health status
 Inter-censal migration flows
 Residential concentration/segregation and poor health
Section 75 Related
 Equality assessment of health outcomes: cause-specific mortality for
Section 75 groups (DHSSPS)
 Mortality rates and life-expectancy: Section 75 groups and social
disadvantage (OFMDFM)
 Religious affiliation and self-reported health
 Denominational differences in short-term mortality
 Risk of admission to care homes for older people
 Social harm and the elderly in Northern Ireland
Distinct Linkage Projects (DLPs)
 Potential to link to health and social services data for specially defined
one-off studies; so far successfully linked to Breast Screening, Dental
Activity and Prescribing data
 Legal and ethical scrutiny and privacy protection protocols:
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Study period and specific data transfers agreed (DTA)
Legal basis for data transfer (DTA)
Health and Social Care Privacy Advisory Committee informed
Ethics – database modification application (ORECNI)
 One-way encryption methodology:
 developed in Scotland to safeguard sensitive census and health and care
data
 datasets are matched and merged on an encrypted unique identifier
 researchers not involved in the linkage processes; only have access to an
anonymised dataset
DLPs Based on the NILS
 BSO dental activity data:
- adolescent dental health and use of dental care services (PhD thesis)
- child dental health and use of dental care services (ongoing)
 QARC breast screening data: variations in breast screening uptake
(submitted as PhD thesis)
 BSO EPES data: use of antibiotics by demographic and area
characteristics
(ongoing prelim results available at NISRA Conference Nov 2010)
 Social services admin data: children and families with long term and
complex needs
(ongoing)
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Introduction & Background to the Northern Ireland Longitudinal
Study (NILS)

Role of the NILS Research Support Unit

Research Projects: Policy Relevant Themes

Policy Outreach & Government Users

Research Findings: Implications for Policy
Policy Outreach
NILS/NIMS data have obvious policy-relevance.
There are two main ways there can be policy engagement:
1. government researchers become involved in NILS projects
2. researchers (academic and government) engage policymakers with their findings
 personal contact (formalised through project applications)
 dissemination of findings through:
- RSU Ezine ‘NILS Newsletter’
- Policy/Research Briefs
- NILS-RSU website
www.nils-rsu.census.ac.uk
Research Findings: Examples of Two
NILS Projects
 A study of the socio-demographic and area correlates of
suicides in NI (005)
O’ Reilly, D., Rosato, M., Connolly, S. and Cardwell, C. (2008) Area
factors and suicide: 5-year follow-up of the Northern Ireland population.
Br J Psychiatry 192(2):106-11.
 Influence of demographic, socio-economic and area level
factors on uptake of routine breast screening in NI (021)
Kinnear, H., Uptake of Breast Screening: Where You live Also
Matters.Presented at Society for Social Medicine Conference , QUB,
Sept 2010
Area Factors & Suicide (i)
Background:
Suicide rates vary between areas: is this due to individual characteristics
(composition) or area characteristics (context)?
Aim:
To determine if area factors are independently related to
suicide risk after adjustment for individual and family
characteristics.
Method:
A 5-year record linkage study, based on the NIMS database, was
conducted of c. 1.1 million individuals (not in communal establishments)
aged 16–74 years, enumerated at the 2001 Northern Ireland Census.
- data anonymised and held in a safe setting
Area Factors & Suicide (ii)
Results:
1. The cohort experienced 566 suicides during follow-up.
2. Suicide risks:
i. lowest for women and for those who were married or
cohabiting;
ii. strongly related to individual and household disadvantage
and economic and health status.
3. The higher rates of suicide in the more deprived and socially
fragmented areas disappeared after adjustment for individual
and household factors.
4. There was no significant relationship between population
density and risk of suicide.
Area Factors & Suicide (iii)
Conclusions:
Differences in rates of suicide between areas are
predominantly due to population characteristics rather
than to area-level factors.
Policy implication? Policies targeted at area-level factors
are unlikely to significantly influence suicides rates.
Suicide (Daily Mirror)
Uptake of Breast Screening
Background:
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All women aged between 50-64 invited once every 3 years for breast
screening in NI
Current uptake rate in UK is about 76-77%
Uptake is lower in inner city areas (London ~ 64%)
Aim:
To describe and explain demographic, socio-economic and area-level variations in
attendance at breast screening for women who were routinely invited during the
2001-2004 period.
Method:
Linking of 2 highly sensitive datasets (NILS and Breast Screening data) and
therefore involved following processes:
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ORECNI ethical approval
PAC commendation
one-way encryption
all analyses carried out in NISRA – safe setting
Uptake: demographic factors
Results slides removed due to dissemination restrictions
Uptake: socio-economic factors
Results slides removed due to dissemination restrictions
Uptake: area differentials
Results slides removed due to dissemination restrictions
Policy implications
 Urban dwellers less concerned about health?
 Difficulties informing women in some areas?
 Difficulties with access to clinics and/or opening
times?
 Perhaps not non-attenders but non-invitees?
 Perhaps many women in more urban areas do not
receive their invitation letters because the address used
by the call-recall system for the invitation letter is
incorrect.
Future Plans
Potential Projects
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Pharmaco-epidemiological studies using EPES
Travel-to-work: do longer distance commutes lead to residential
moves?
Research Ideas
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Cancer research Northern Ireland Cancer Registry data
Hospital admissions using Hospital Inpatient System data
Rural inequalities in health
NILS-RSU Activity
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NILS Research User Forum
STATA training
Working/Technical Paper Series
Acknowledgements
The help provided by the staff of the Northern Ireland
Longitudinal Study and the Northern Ireland Mortality
Study (NILS and NIMS) and the NILS Research Support
Unit is acknowledged.
The NILS and NIMS are funded by the Health and Social
Care Research and Development Division of the Public
Health Agency (HSC R&D Division) and NISRA. The
NILS-RSU is funded by the ESRC and Northern Ireland
Government.
The authors alone are responsible for the
interpretation of the data.
NILS Research Support Unit
Northern Ireland Statistics and Research Agency
McAuley House
2-14 Castle Street
Belfast
BT1 1SA
Tel: 028 90 348138
Email: [email protected]
Website: nils-rsu.census.ac.uk