Type 2 Diabetes in Older Well-Functioning People: Who Is Undiagnosed?: Data from the Health, Aging, and Body Composition Study

Article (PDF Available)inDiabetes Care 24(12):2065-70 · December 2001with15 Reads
DOI: 10.2337/diacare.24.12.2065 · Source: PubMed
Abstract
To assess, in an older population, the prevalence of diagnosed and undiagnosed diabetes, the number needed to screen (NNTS) to identify one individual with undiagnosed diabetes, and factors associated with undiagnosed diabetes. Socioeconomic and health-related factors were assessed at the baseline examination of the Health, Aging, and Body Composition (Health ABC) Study, a cohort of 3,075 well-functioning people aged 70-79 years living in Memphis, Tennessee and Pittsburgh, Pennsylvania (42% blacks and 48% men). Diabetes was defined according to the 1985 World Health Organization criteria (fasting glucose > or =7.8 mmol/l or 2-h glucose > or =11.1 mmol/l) and the 1997 American Diabetes Association criteria (fasting glucose > or =7.0 mmol/l). The prevalence of diagnosed and undiagnosed diabetes was 15.6 and 8.0%, respectively, among all participants (NNTS 10.6), 13.9 and 9.1% among white men (NNTS 9.5), 7.8 and 7.4% among white women (NNTS 12.4), 22.7 and 9.1% among black men (NNTS 8.5), and 21.6 and 6.2% among black women (NNTS 12.6). In multivariate analyses, compared with individuals without diabetes, individuals with undiagnosed diabetes were more likely to be men and were more likely to have a history of hypertension, higher BMI, and larger waist circumference. NNTS was lowest in men (9.1), individuals with hypertension (8.7), individuals in the highest BMI quartile (6.9), and individuals in the largest waist circumference quartile (6.8). In approximately one-third of all older people with diabetes, the condition remains undiagnosed. Screening for diabetes may be more efficient among men and individuals with hypertension, high BMI, and large waist circumference.
Type 2 Diabetes in Older Well-
Functioning People: Who Is
Undiagnosed?
Data from the Health, Aging, and Body Composition Study
LONNEKE V. FRANSE,
MS
C
1,2
MAURO DI BARI,
MD
,
PHD
1,3
RON I. SHORR,
MD
,
MS
1
HELAINE E. RESNICK,
PHD
4
JACQUES T. M. VAN EIJK,
PHD
5
DOUG C. BAUER,
MD
6
ANNE B. NEWMAN,
MD
,
PHD
7
MARCO PAHOR,
MD
8
FOR THE HEALTH,AGING, AND BODY
COMPOSITION STUDY GROUP
OBJECTIVE To assess, in an older population, the prevalence of diagnosed and undiag-
nosed diabetes, the number needed to screen (NNTS) to identify one individual with undiag-
nosed diabetes, and factors associated with undiagnosed diabetes.
RESEARCH DESIGN AND METHODS Socioeconomic and health-related factors
were assessed at the baseline examination of the Health, Aging, and Body Composition (Health
ABC) Study, a cohort of 3,075 well-functioning people aged 70–79 years living in Memphis,
Tennessee and Pittsburgh, Pennsylvania (42% blacks and 48% men). Diabetes was defined
according to the 1985 World Health Organization criteria (fasting glucose 7.8 mmol/l or 2-h
glucose 11.1 mmol/l) and the 1997 American Diabetes Association criteria (fasting glucose
7.0 mmol/l).
RESULTS The prevalence of diagnosed and undiagnosed diabetes was 15.6 and 8.0%,
respectively, among all participants (NNTS 10.6), 13.9 and 9.1% among white men (NNTS 9.5),
7.8 and 7.4% among white women (NNTS 12.4), 22.7 and 9.1% among black men (NNTS 8.5),
and 21.6 and 6.2% among black women (NNTS 12.6). In multivariate analyses, compared with
individuals without diabetes, individuals with undiagnosed diabetes were more likely to be men
and were more likely to have a history of hypertension, higher BMI, and larger waist circumfer-
ence. NNTS was lowest in men (9.1), individuals with hypertension (8.7), individuals in the
highest BMI quartile (6.9), and individuals in the largest waist circumference quartile (6.8).
CONCLUSIONS In approximately one-third of all older people with diabetes, the con-
dition remains undiagnosed. Screening for diabetes may be more efficient among men and
individuals with hypertension, high BMI, and large waist circumference.
Diabetes Care 24:2065–2070, 2001
D
iabetes and its complications are
significant causes of morbidity and
mortality in the U.S. (1,2). Al-
though the prevalence of hypertension
(3), hypercholesterolemia (4), and inci-
dence of and mortality from heart disease
(5,6) and stroke (7) are markedly declin-
ing, the prevalence of diabetes remains
high and is expected to increase further,
especially in the older population (8). Ac-
cording to the Third National Health and
Nutrition Examination Survey, 1988
1994 (NHANES III), the prevalence of
physician-diagnosed and undiagnosed
diabetes (based on the 1985 World
Health Organization [WHO] criteria) in
people aged 60 –74 years is 12.6 and
10.8%, respectively (9), resulting in a to-
tal prevalence of 23.4%.
Many individuals with diabetes re-
main unidentified, untreated, and at risk
for complications. Since the American Di-
abetes Association (ADA) introduced new
diagnostic criteria for type 2 diabetes
(10), the exclusive use of fasting glucose
to define glucose tolerance has been de-
bated. It has been suggested that by ap-
plying the new diagnostic criteria,
diabetes may remain undiagnosed in even
more individuals (11). Undiagnosed dia-
betes may have substantial public health
implications (12–15), but little is known
about the risk factors for undiagnosed di-
abetes. The objectives of this study were
to determine the prevalence of undiag-
nosed diabetes in a large population of
older adults, the number needed to screen
to identify one undiagnosed person, and
the characteristics of the individuals that
might be most effectively targeted with
screening programs.
RESEARCH DESIGN AND
METHODS Diabetes was assessed
at the baseline examination of the Health,
Aging, and Body Composition (Health
ABC) Study. Health ABC is a 7-year pro-
spective study of changes in body compo-
sition, weight-related health conditions,
●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●
From the
1
Department of Preventive Medicine, University of Tennessee, Memphis, Tennessee; the
2
Institute
for Research in Extramural Medicine (EMGO), Vrije Universiteit, Amsterdam, the Netherlands; the
3
Depart
-
ment of Gerontology and Geriatrics, University of Florence and ‘Careggi’ Hospital, Florence, Italy;
4
MedStar
Research Institute, Washington, DC; the
5
Department of Medical Sociology, University of Maastricht, Maas
-
tricht, the Netherlands; the
6
Prevention Sciences Group, University of California, San Francisco, California;
the
7
Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and the
8
Sticht Center on Aging, Department of Internal Medicine, Wake Forest University School of Medicine,
Winston-Salem, North Carolina.
Address correspondence and reprint requests to Lonneke Franse, MSc, Comprehensive Cancer Center
South, P.O. Box 231, 5600 AE, Eindhoven, the Netherlands. E-mail: l.vd.poll@ikz.nl.
Received for publication 16 May 2001 and accepted in revised form 21 August 2001.
Abbreviations: ADA, American Diabetes Association; Health ABC, Health, Aging, and Body Composi-
tion; NHANES III, Third National Health and Nutrition Examination Survey; NNTS, number needed to
screen; OGTT, oral glucose tolerance test; WHO, World Health Organization.
A table elsewhere in this issue shows conventional and Syste`me International (SI) units and conversion
factors for many substances.
Epidemiology/Health Services/Psychosocial Research
ORIGINAL ARTICLE
DIABETES CARE, VOLUME 24, NUMBER 12, DECEMBER 2001 2065
and incident functional limitation. The
study population consists of 3,075 indi-
viduals aged 7079 years, 42% of whom
are black and 48% of whom are men. Par-
ticipants were identied from the Medi-
care-eligible population residing in the
Memphis, Tennessee and Pittsburgh,
Pennsylvania area. To be eligible, partici-
pants had to report no difculty in walk-
ing for 0.25 mile (400 m), walking up 10
steps, getting in and out of bed or chairs,
bathing or showering, dressing, or eating
and must report no need of using a cane,
walker, crutches, or other special equip-
ment to get around. All procedures re-
lated to Health ABC received Institutional
Review Board approval from the partici-
pating institutions.
Measures
The baseline home visit questionnaire,
administered between April 1997 and
May 1998, assessed demographic and so-
cioeconomic characteristics, health be-
haviors, and health status, including
medical history. The subsequent baseline
clinic visit, conducted within 2 weeks of
the interview, included a fasting glucose
measurement and a 75-g oral glucose tol-
erance test (OGTT) performed after an
8-h overnight fast.
Diabetic status was dened by self-
reported response to the question Has a
doctor ever told you that you have diabe-
tes or sugar diabetes? (excluding diabetes
that only occurred during pregnancy). If
so, participants were asked if they cur-
rently used insulin or hypoglycemic
agents. Except for those who reported
taking insulin or oral hypoglycemic
agents, participants underwent an OGTT.
Participants who did not report prior di-
agnosis of diabetes were classied accord-
ing to the 1985 WHO criteria: fasting
glucose concentration 7.8 mmol/l
(140 mg/dl) or a 2-h glucose concentra-
tion of 11.1 mmol/l (200 mg/dl). For
additional analyses, participants who did
not report prior diagnosis of diabetes
were also classied according to the 1997
ADA criteria: fasting glucose concentra-
tion 7.0 mmol/l (126 mg/dl). Partici-
pants were classied as undiagnosed if
they reported no prior diagnosis of diabe-
tes but met the WHO or ADA criteria for
diabetes.
We used both WHO criteria and
1997 ADA criteria because at the time of
most baseline interviews, the ADA criteria
were just being disseminated. To com-
pare our results with older and current
reports, we applied both WHO and ADA
criteria in analyses. For both classica-
tions, we included only participants who
had both fasting and 2-h glucose mea-
surements. Of the 3,075 participants in
Health ABC, 125 were missing either fast-
ing glucose or the OGTT and were ex-
cluded from this analysis, leaving an
analysis sample of 2,950 participants
(95.9% of the cohort).
The demographic and socioeconomic
characteristics assessed included partici-
pants self-reported age, sex, race, years of
education, and annual family income.
Health behavior included self-reported
current and past smoking and alcohol use
in the past 12 months. Health service use
involved measures of having a usual
source of care (Do you have a doctor or
place that you usually go to for health care
or advice about your health care?), hav-
ing a health insurance plan in addition to
Medicare, and hospitalization in the year
before the baseline interview.
Health conditions were assessed
based on self-reported history of cancer,
hypertension, and cardiovascular disease
(myocardial infarction, angina pectoris,
congestive heart failure, intermittent
claudication, transient ischemic attack,
stroke, and rheumatic heart disease) or
any medical procedure in heart, neck, or
blood vessels, such as an angioplasty or
bypass surgery. Height (mm) was mea-
sured twice by a Harpenden stadiometer
(Holtain, Crosswell, U.K.) and weight was
measured by a standard balance-beam
scale to the nearest 0.1 kg. Using the mean
of the two height measurements, BMI (kg/
m
2
) was calculated as weight divided by
the square of height. Waist circumference
was measured in centimeters.
For the analyses of each potential pre-
dictor, we excluded participants who had
missing information on that particular
variable. Except for annual family income
(410 participants [14%] were missing this
information), 020 participants (1%)
were missing information for all variables.
Analyses
Statistical analyses were performed using
the SPSS version 8.0 for Windows soft-
ware package (SPSS, Chicago, IL) (16).
Analysis of variance for multiple depen-
dent variables by one or more factor vari-
ables was used to assess differences in
fasting glucose and HbA
1c
between diag
-
nosed and undiagnosed diabetic partici-
pants. A
2
test was used to assess
differences in prevalence of diabetes be-
tween different race and sex groups. Lo-
gistic regression analysis was used to
assess associations between potential pre-
dictors and (un)diagnosed diabetes (ver-
sus no diabetes), after adjusting for age,
sex, and race. Risk factors for diagnosed
diabetes are presented so that direct com-
parison with risk factors for undiagnosed
diabetes is possible. To calculate the num-
ber needed to screen (NNTS) to identify
one individual with undiagnosed diabetes
in each individual subgroup, the number
of undiagnosed plus nondiabetic subjects
was divided by the number of undiag-
nosed diabetic subjects.
RESULTS The prevalence of diabe-
tes, using the 1980 1985 WHO criteria,
was highest in black men (31.8%) com-
pared with white men and women (P
0.001 versus white men and women) (Ta-
ble 1). White women had the lowest prev-
alence of diabetes (15.3%; P 0.001
versus other subgroups), which was al-
most half the prevalence in black women
(27.8%). The prevalence of undiagnosed
diabetes was not signicantly different in
white women (7.4%) compared with
black women (6.2%). The prevalence of
undiagnosed diabetes was similar among
white and black men (9.1%). Additional
analyses, using the fasting 1997 ADA cri-
teria, revealed that the total prevalence of
diabetes was 4 6% lower than the 1985
WHO criteria (Table 1). The prevalence
of undiagnosed diabetes was again higher
in men (white men 5.1%, black men
5.3%) than in women (white women
1.5%, black women 2.8%).
The association of age, race, sex, and
site with diagnosed and undiagnosed di-
abetes (according to the 1985 WHO cri-
teria) compared with no diabetes was
assessed in a multivariate logistic regres-
sion model. Compared with women, men
had a higher risk of both diagnosed and
undiagnosed diabetes. Black race was
strongly and signicantly associated with
a higher risk of diagnosed diabetes, inde-
pendent of age and sex (Table 2). Race
was not signicantly associated with un-
diagnosed diabetes.
In subsequent multivariate logistic re-
gression analyses adjusted for age, race,
and sex, the risk of having diagnosed di-
abetes decreased with increasing years of
education, increasing income levels, and
increasing use of alcohol (Table 3). The
Undiagnosed diabetes
2066 DIABETES CARE, VOLUME 24, NUMBER 12, DECEMBER 2001
risk of having diagnosed diabetes was
positively associated with access to a doc-
tor for health care, hospitalization during
the last year, history of hypertension, his-
tory of cardiovascular disease, and in-
creasing quartiles of BMI and waist
circumference. The risk of having undiag-
nosed diabetes was positively associated
with a history of hypertension and in-
creasing BMI and waist circumference
quartiles. In a multivariate model includ-
ing age, race, sex, history of hypertension,
BMI, and circumference, only male sex
(odds ratio 1.4, 95% CI 1.11.9) and his-
tory of hypertension (1.5, 1.12.0) were
signicantly associated with undiagnosed
diabetes.
The results were virtually unchanged
when the same multivariate logistic re-
gression analyses were performed using
the 1997 ADA fasting glucose criteria
(data not shown). Applying these criteria,
men were at even higher risk for having
undiagnosed diabetes (odds ratio 2.8,
95% CI 1.8 4.3) than women. In addi-
tion, using the 1985 WHO fasting criteria
(fasting glucose 7.8 mmol/l) without
using the OGTT, the same risk factors for
undiagnosed diabetes were again identi-
ed. The prevalence of diabetes was
17.5%.
Comparing race and sex groups, the
NNTS to identify one person with undi-
agnosed diabetes was lowest in black men
(8.5) and signicantly lower than the
NNTS in black women (12.6; P 0.02)
and white women (12.4; P 0.03) (Table
1). Furthermore, small NNTS were found
among people with a history of hyperten-
sion (8.7) and those in the highest quar-
tiles of BMI (6.9) or waist circumference
(6.8). Consequently, combinations of
these risk factors result in lower NNTS
(Fig. 1). Because the prevalence of undi-
agnosed diabetes was 4 6% lower using
the 1997 ADA criteria, the calculated
NNTS was signicantly higher in all sub-
groups (Table 1).
CONCLUSIONS The present
study shows that diabetes remains undi-
agnosed in approximately one-third of all
older individuals. In this study of health-
ier older adults, men, individuals with a
history of hypertension, and individuals
with high BMI and large waist circumfer-
ence were at highest risk of having undi-
agnosed diabetes. Screening for diabetes
may be more efcient among these sub-
groups, especially among individuals
with combinations of these risk factors, in
which the NNTS to identify one undiag-
nosed diabetic was lowest.
The prevalence of diabetes in this
study was similar to estimates reported in
NHANES III (9). Overall, American mi-
norities were more frequently affected by
diabetes, but the racial difference de-
clined in older age groups. Indeed, 22.7%
Table 1Prevalence of diagnosed diabetes, undiagnosed diabetes, and NNTS according to 1985 WHO criteria and 1997 ADA criteria,
stratified by race and sex
Total
(n 2,950)
White (n 1,732) Black (n 1,218)
Men (n 913) Women (n 819) Men (n 528) Women (n 690)
Diagnosed diabetes 460 (15.6) 127 (13.9) 64 (7.8) 120 (22.7) 149 (21.6)
1985 WHO criteria
Undiagnosed diabetes 235 (8.0) 83 (9.1) 61 (7.4) 48 (9.1) 43 (6.2)
Total diabetes prevalence* 695 (23.6) 210 (23.0) 125 (15.3) 168 (31.8) 192 (27.6)
NNTS§ 10.6 9.5 12.4 8.5 12.6
1997 ADA criteria
Undiagnosed diabetes 106 (3.6) 47 (5.1) 12 (1.5) 28 (5.3) 19 (2.8)
Total diabetes prevalence* 566 (19.2) 174 (19.1) 76 (9.3) 148 (28.0) 168 (24.3)
NNTS 23.5 16.7 62.9 14.6 28.5
Data are n (%). *Undiagnosed plus diagnosed diabetes; participants who reported prior diagnosis by a physician; participants who met diabetes criteria but
responded noto the question Has a doctor ever told you that you have diabetes?; §NNTS smaller in all subgroups compared with ADA criteria; P 0.05 versus
white and black women; P 0.05 versus white women.
Table 2Risk of having diagnosed or undiagnosed diabetes (according to 1985 WHO criteria) compared with no diabetes
n (%)
Odds ratio (95% CI) of
having diagnosed type
2 diabetes
Odds ratio (95% CI) of
having undiagnosed
type 2 diabetes NNTS
Age
73 years (median age)* 1,538 (52.1) 1.0 1.0 11.1
73 years 1,412 (47.9) 1.0 (0.81.3) 1.1 (0.81.4) 10.1
Sex
Female 1,509 (51.2) 1.0 1.0 12.5
Male 1,441 (48.8) 1.4 (1.21.7)§ 1.4 (1.11.9)§ 9.1
Race
Black 1,218 (41.3) 1.0 1.0 10.4
White 1,732 (58.7) 0.4 (0.30.5) 0.9 (0.71.2) 10.7
*Adjusted for sex and race, adjusted for age and race. adjusted for age and sex; §P 0.05; P 0.001; P 0.05 compared with male sex.
Franse and Associates
DIABETES CARE, VOLUME 24, NUMBER 12, DECEMBER 2001 2067
Table 3Risk of having diagnosed or undiagnosed diabetes (according to 1985 WHO criteria) compared with no diabetes
n (%)
Odds ratio (95% CI) of
having diagnosed type
2 diabetes*
Odds ratio (95% CI) of
having undiagnosed
type 2 diabetes* NNTS
Socioeconomic
Education (years)
011 711 (24.1) 1.0 1.0 9.6
1214 1,000 (33.9) 0.9 (0.71.2) 1.1 (0.71.5) 9.6
15 1,232 (41.8) 0.7 (0.50.9) 0.8 (0.51.1) 12.4
P trend 0.01 P trend 0.08
Annual family Income ($)
10,000 347 (11.8) 1.0 1.0 11.4
10,00025,000 1,008 (34.2) 0.7 (0.51.0) 1.1 (0.71.8) 10.3
25,00050,000 779 (26.4) 0.7 (0.50.9) 1.1 (0.61.9) 10.3
50,000 406 (13.8) 0.5 (0.30.7) 1.0 (0.61.9) 10.4
P trend 0.002 P trend 0.99
Health behavior
Smoking
Never 1,294 (43.9) 1.0 1.0 11.7
Ever smoked 1,358 (46.0) 1.1 (0.91.4) 1.2 (0.91.6) 9.2
Currently smoking 293 (9.9) 0.7 (0.51.1) 0.7 (0.41.2) 14.7
Alcohol use in past 12 months
Never 1,482 (50.2) 1.0 1.0 11.3
Occasional 612 (20.7) 0.5 (0.40.7) 1.1 (0.81.6) 10.2
17 drinks/week 632 (21.4) 0.4 (0.30.5) 1.0 (0.71.5) 10.7
8 drinks/week 213 (7.2) 0.2 (0.10.4) 1.3 (0.82.1) 8.4
P trend 0.001 P trend 0.46
Health service use
Doctor to usually go to
No 167 (5.7) 1.0 1.0 8.1
Yes 2,775 (94.1) 7.3 (3.018.0) 0.7 (0.51.2) 10.8
Health insurance plan in addition to Medicare
No 560 (19.0) 1.0 1.0 9.6
Yes 2,370 (80.3) 1.0 (0.81.3) 0.9 (0.61.3) 10.9
Hospitalization last year
No 2,505 (84.9) 1.0 1.0 10.9
Yes 439 (14.9) 1.5 (1.11.9) 1.2 (0.81.7) 9.2
Physical health conditions
History of cancer
No 2,381 (80.7) 1.0 1.0 10.9
Yes 562 (19.1) 0.9 (0.71.2) 1.2 (0.81.6) 9.4
History of hypertension
No 1,419 (48.1) 1.0 1.0 13.4
Yes 1,508 (51.1) 2.2 (1.82.8) 1.7 (1.32.2) 8.7§
History of cardiovascular disease/procedures
No 2,023 (68.6) 1.0 1.0 11.4
Yes 927 (31.4) 1.5 (1.21.8) 1.2 (0.91.7) 9.0
BMI (kg/m
2
)
24.1 734 (24.9) 1.0 1.0 15.6
24.126.8 738 (25.0) 1.5 (1.02.0) 1.0 (0.71.6) 14.6
26.930.0 734 (24.9) 2.0 (1.42.8) 1.7 (1.12.6) 9.3
30.1 744 (25.2) 3.2 (2.34.3) 2.6 (1.73.8) 6.9
P trend 0.001 P trend 0.001
Waist circumference (cm)
91.8 736 (24.9) 1.0 1.0 17.3
91.899.3 743 (25.2) 1.8 (1.32.5) 1.3 (0.82.0) 13.4
99.4107.1 731 (24.8) 2.4 (2.73.3) 1.9 (1.22.9) 9.2
107.2 734 (24.9) 3.8 (2.85.2) 2.7 (1.84.1) 6.8
P trend 0.001 P trend 0.001
*Adjusted for age, sex, and race; P 0.05; P 0.001; §P 0.05; P 0.05 compared with rst and second quartile; quartiles.
Undiagnosed diabetes
2068 DIABETES CARE, VOLUME 24, NUMBER 12, DECEMBER 2001
of white men, 22.1% of white women,
26.5% of black men, and 31.7% of black
women aged 60 74 years were diabetic in
NHANES III, using WHO criteria. The
percentage of undiagnosed diabetes in
this older population was 11.8% in white
men, 10.4% in white women, 9.7% in
black men, and 7.8% in black women.
The higher prevalence of diabetes
found when applying WHO compared
with the fasting glucose ADA criteria may
be explained by the higher sensitivity of
the glucose tolerance test in older individ-
uals (11), particularly in women, who
tend to have higher post challenge glu-
cose levels than men (17). Furthermore,
American men generally have higher fast-
ing glucose levels than women (9). Higher
post challenge glucose levels in combina-
tion with lower fasting glucose levels
could also explain our nding that
women, compared with men, were at sig-
nicantly lower risk for undiagnosed dia-
betes when we used the ADA or WHO
fasting criteria. Longitudinal studies
showed that the new fasting ADA criteria
were less predictive than the WHO crite-
ria for the burden of cardiovascular dis-
ease (1) and mortality (2) associated with
abnormal glucose, especially in the el-
derly. Therefore, a screening program
based only on fasting glucose would miss
a large proportion of older people with
important metabolic disorders.
In contrast with NHANES III (9), we
did not nd an association between age
and the risk of undiagnosed or diagnosed
diabetes, probably because of the narrow
age range (70 79 years) in our study. The
higher risk of undiagnosed diabetes in in-
dividuals with hypertension, high BMI,
and large waist circumference probably
point to the common ground of diabetes
and cardiovascular disease (18) and con-
rms the importance of monitoring glu-
cose levels in people with cardiovascular
risk factors.
In subgroups with a low risk of diag-
nosed diabetes, such as whites, those with
higher income, and more years of educa-
tion, the risk of having undiagnosed dia-
betes was not signicantly lower
compared with blacks, individuals with
lower income, and individuals with fewer
years of education. These subgroups may
be characterized by mildertypes of dia-
betes and may have a higher probability of
remaining undiagnosed. The severity of
diabetes, as measured by mean fasting
glucose and HbA
1c
, was less in individu
-
als undiagnosed according to the WHO
criteria (125 mg/dl and 6.9%, respec-
tively) compared with individuals with
diagnosed diabetes (155 mg/dl and 8.0%,
respectively; P 0.001 when comparing
both groups). These people are probably
less likely to develop complications com-
pared with those with higher glucose lev-
els who are aware of their condition.
Another explanation could be that certain
subgroups are considered to be at low risk
of diabetes and, therefore, are less fre-
quently evaluated. Analyses of NHANES
II (19761980) showed that screening
rates increased with increasing number of
risk factors for diabetes, but even among
those with three risk factors, only 38.6%
reported to be evaluated in the year before
the study (19). Longitudinal cost-
effectiveness analyses are necessary to
fully assess the benets of early detection
and treatment in different subgroups
(20).
The fact that the risk of undiagnosed
diabetes was similar in black and white
individuals could also suggest that the
message about increased risk of diabetes
is reaching some parts of the black com-
munity (at least this cohort) and their
health care providers. However, we do
not know from our data whether those
with diagnosed diabetes are getting ade-
quate treatment. In addition, our sample
may not be representative of black people
in general.
Several limitations of our study must
be acknowledged. First, the cross-
sectional study design makes it difcult to
draw inferences about causal pathways.
Second, fasting glucose and 2-h glucose
were only measured once. Because the di-
agnostic criteria of WHO and ADA both
require two independent fasting samples
to diagnose diabetes, this could lead to
misclassication of some individuals.
However, it is unlikely that this would
have changed the set of predictors of un-
diagnosed diabetes that we identied, be-
cause they were virtually the same when
using WHO, ADA, or WHO-exclusive
fasting criteria. Third, because 14% of the
participants were missing information on
annual family income, we must be careful
with the interpretation of income as a risk
factor for (un)diagnosed diabetes. Last,
this study population represents the well-
functioning fraction of the older popula-
tion, in an equally balanced racial design
that may not be a representative sample of
the overall U.S. population aged 70 79
years. The selection of relatively healthier
people might have resulted in a lower
prevalence of diabetes. Unlike NHANES,
Health ABC was not intended to reect
the Medicare population of the U.S., and
extrapolation of our ndings to all elderly
individuals in the U.S. should be done
with caution.
Public health implications
Our ndings have potentially relevant
public health implications. It is estimated
that there will be a 42% increase in prev-
alence of diabetes among adults in devel-
oped countries by the year 2025; the U.S.
will be one of the three countries with the
largest number of people with the disease
(8). In the future, this increase could off-
set the benets of better control of hyper-
tension, hypercholesterolemia, and
reduction of smoking on the risk of car-
diovascular disease in the community, es-
pecially if one-third of the individuals
with the disease remain undiagnosed. In
the clinical recommendations of 2001,
the ADA states that, based on the current
lack of scientic evidence, community
screening for diabetes, even in high-risk
populations, is not recommended. Never-
theless, there is sufcient indirect evi-
dence to justify opportunistic screening
in a clinical setting of individuals at high
risk (21). The NNTS found in our study
suggests that screening for diabetes may
be more efcient among men and individ-
uals with hypertension, high BMI, and
large waist circumference.
AcknowledgmentsThis study was sup-
ported by the National Institute on Aging Con-
tract nos. N01-AG-6-2,106; N01-AG-6-
2,102; and N01-AG-6-2,103. Marco Pahor
was supported by the Claude D. Pepper Older
Figure 1—NNTS among different subgroups.
HTN, hypertension.
Franse and Associates
DIABETES CARE, VOLUME 24, NUMBER 12, DECEMBER 2001 2069
Americans Independence Center Grant no.
NIA P60 AG10484
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    • "Nonetheless, these findings may reflect poorer access to health services for those in lower socioeconomic groups and those who reside in areas outside of Ireland's major city and warrant further investigation . Previous studies have indicated that undiagnosed diabetes may be more common in men, those with a history of hypertension [41] and obese individuals [42], which was not evident in this study. Due to the small number of cases of undiagnosed diabetes, the analysis may have been underpowered to detect significant differences for these and other factors. "
    [Show abstract] [Hide abstract] ABSTRACT: Aims: The prevalence of type 2 diabetes and pre-diabetes has increased rapidly in recent decades and this trend will continue as the global population ages. This study investigates the prevalence of, and factors associated with, diagnosed and undiagnosed type 2 diabetes mellitus and pre-diabetes in older adults in Ireland. Methods: Cross-sectional data from 5377 men and women aged 50 and over from Wave 1 of the Irish Longitudinal Study on Ageing (TILDA) was analysed. Diagnosed diabetes was defined using self-reported doctors' diagnosis and medications data. Glycated haemoglobin (HbA1c) analysis was used to identify undiagnosed and pre-diabetes. Age and sex-specific prevalence estimates were generated. Logistic regression was used to investigate the association between diabetes classification and the demographic, health and lifestyle characteristics of the population. Results: The prevalence of diagnosed and undiagnosed type 2 diabetes was 8.6% (95% confidence interval (CI): 7.6-9.5%) and 0.9% (95% CI: 0.6-1.1%) respectively. Diabetes was more prevalent in men than women and increased with age. The prevalence of pre-diabetes was 5.5% (95% CI: 4.8-6.3%) and increased with age. Diabetes and pre-diabetes were independently associated with male sex, central obesity and a history of hypertension, while undiagnosed diabetes was associated with geographic location and medical costs cover. Conclusion: Despite high rates of obesity and other undiagnosed health conditions, the prevalence of undiagnosed and pre-diabetes is relatively low in community-dwelling older adults in Ireland. Addressing lifestyle factors in this population may help to further reduce the prevalence of pre-diabetes and improve outcomes for those with a previous diagnosis.
    Full-text · Article · Nov 2015
    • "MS may increase the risk for coronary artery disease, stroke, and diabetes [11, 12]. Undiagnosed metabolic disorders may also impose substantial public health implications because these subjects remain untreated and at risk for complications [13]. Very recently a research group from Japan has done an electronic health review and found that obesity and hypertension are very high among the general population of Bangladesh [14]. "
    [Show abstract] [Hide abstract] ABSTRACT: Selecting healthy control for any research has become a serious problem in developing countries. General populations are usually unaware of their health condition and progress towards abnormal complication(s) unknowingly. The present study was aimed to estimate health status in the general population of Khulna division in Bangladesh. Purposely adult subjects were selected who were above 30 years and free from any known ailment. Both anthropometric and biochemical parameters were measured and calculated by standard procedures. Health screening of the population indicated that a substantial number of subjects were suffering from undiagnosed hyperglycemia, hyperlipidemia (triglyceride, cholesterol and low density lipoprotein), and abnormal level of high density lipoprotein, creatinine and serum glutamate-pyruvate transaminase. A considerable number of subjects were found to be underweight, overweight or obese. The ratio of abnormality was higher in female compared to its male counterpart.
    Full-text · Article · Aug 2015 · Journal of Bio-Science
    • "Considering the dangers of not controlling diabetes, it is scary how many have diabetes undiagnosed. The United States estimated to have an undiagnosed diabetes population of 2.7% of the entire adult population over the age of 20 and prevalence of undiagnosed diabetes was similar among white and black men (9.1%) (Franse et al. 2001). In Sardinian population, the prevalence of undiagnosed diabetes was 5.65% (5.20% and 6.15%, females and males, respectively) (Muntoni et al. 2008). "
    [Show abstract] [Hide abstract] ABSTRACT: Context: Undiagnosed cases of diabetes mellitus constitute a major proportion of diabetic patients in the developing countries due to lack of proper screening and primary care facilities. Generation of evidence on undiagnosed cases is highly important for the estimation of the true burden of this disease. Objectives: The present study was undertaken to explore the proportion of undiagnosed diabetes and associated disorders in a middle aged Bangladeshi population living in the capital city of Bangladesh. Materials and Methods: Under a cross-sectional observational design a group of 254 middle aged (35-60 yrs) subjects (146♂ and 108) were included in the study who previously were unaware about the existence of diabetes or its complications. A 2-sample OGTT was done and blood glucose was estimated by glucose-oxidase method and Serum total cholesterol, HDL and TG by enzymatic colorimetric (Cholesterol Oxidase /Peroxidase, CHOD-PAP) method. Glycemic and other abnormalities were diagnosed and classified as per WHO criteria. Results: Out of the total 254 subjects 34 (15.1%) were found to have type 2 diabetes mellitus (T2DM) and 49 (19.29%) were prediabetics (24.5%-IFG, 75.5% -IGT and 20.4% had combined IFG-IGT). WHR (the indicator of central obesity) was present in higher proportions of diabetic (93.9%) and prediabetics (89.9%) compared to 76.0% control (λ2=8.815; p=0.017). Male subjects had significantly higher central obesity compared to females both in the controls (t=3.929; p<0.0001) and in T2DM groups (t=2.608; p=0.015). Dyslipidemia (judged by triglyceride value) was present among 64.7% in T2DM, 40.8% in Prediabetes and 47.9% in the Controls). In Prediabetes group 80% males had dyslipidemia compared to 20% females (p=0.008). Conclusion: Almost twice the proportion of reported diabetic and prediabetic cases in Bangladesh is still undiagnosed and a substantial proportion of these cases have generalized as well as central obesity and dyslipidemia.
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    M DasM DasZ HassanZ HassanO FaruqueO Faruque+1more author...[...]
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