North West
Adelaide
Health Study
Cumulative diabetes incidence:
ten-fold risk among those
with impaired fasting glucose
Patrick Phillips, Catherine Chittleborough, Anne
Taylor,
& the North West Adelaide Study Team
North West
Adelaide
Health Study
Background
v
Impaired fasting glucose (IFG) is a significant
pre-cursor for the development of diabetes
Î
Aim to examine cumulative incidence of
diabetes in a representative sample among
those with and without IFG
North West
Adelaide
Health Study
The North West Adelaide
Health Study
v
Biomedical cohort study
v
Established in 2000
v
Collaboration between The Queen Elizabeth
Hospital, Lyell McEwin Health Service,
South Australian Department of Health,
University of Adelaide, University of South
Australia
v
Designed to assess prevalence of priority
conditions, risk factors and determinants
across continuum, and progression over time
North West
Adelaide
Health Study
North West Adelaide, South Australia
North West
Adelaide
Health Study
Methods
v Households randomly selected from Electronic
White Pages
v Approach letter sent to households
v CATI
v Person last to have birthday, aged 18+ years,
selected
v Appointment made to attend clinic
v Information pack sent including questionnaire
Response rate - Stage 1
North West
Adelaide
Health Study
Initial sample
n=10096
Eligible sample
n=8213
Interviewed
n=5850
Attended clinic
n=4060
Ineligible
n=1883
18.7%
Non-contacts
n=215
2.6%
Refused interview
n=2148
26.2%
Refused clinic
n=1790
30.6%
Attended clinic / interviewed
= 69.4% participation rate
Attended clinic / eligible sample
= 49.4% response rate
North West
Adelaide
Health Study
Response rate - Stage 2
Initial sample
n=4060
Deceased n=100
Duplicate IDs n=3
Eligible sample
n=3957 (97.5%)
Non-contacts
n=233 (5.9%)
No information obtained
n=160 (4.0%)
Information obtained
n=3564 (90.1%)
Telephone interview
n=3485
88.1%
Questionnaire
n=3145
81.2%
Attended clinic
n=3206
81.0%
Diabetes continuum
STAGE 1 (n=4060)
North West
Adelaide
Health Study
No diabetes
79.6%
IFG
≥ 5.6 mmol/L
13.8%
Undiagnosed
diabetes
≥ 7.0 mmol/L
1.0%
Diagnosed
diabetes
5.6%
North West
Adelaide
Health Study
Progression along diabetes
continuum
Status at Stage 1
Cumulative incidence of
diabetes at Stage 2
No diabetes or IFG
(n=3233)
1.0%
IFG ≥ 5.6 mmol/L
(n=561)
9.6%
North West
Adelaide
Health Study
Proportion IFG Î Diabetes
25
Proportion (%)
20
15
10
5
0
Male
Female
Sex
<55 years
55+ years
Age
> $20,000 ≤ $20,000
Income
North West
Adelaide
Health Study
Proportion IFG Î Diabetes
Proportion (%)
20
15
10
5
0
No
Yes
Family history diabetes
< 130/85
≥ 130/85
BP
< 30
≥ 30
BMI
North West
Adelaide
Health Study
Proportion IFG Î Diabetes
35
Proportion (%)
30
25
20
15
10
5
0
≤ 1.7
> 1.7
Triglycerides
≥ 0.9 men, ≥ <0.9 men,
1.1 women <1.1 women
HDL
No
Yes
Smoker
North West
Adelaide
Health Study
Conclusions
v The cumulative incidence of diabetes is almost
10 times greater among those with IFG than
those with normal glucose.
v Early detection of diabetes, particularly among
those with IFG, remains a priority.
North West
Adelaide
Health Study
Contact details
v North West Adelaide Health Study website
http://www.nwadelaidehealthstudy.org
v Population Research & Outcome Studies Unit
(SA Department of Health)
http://www.health.sa.gov.au/pehs/PROS.html