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Abstract
Objective The purpose of the study was to assess the prevalence and correlates of undiagnosed type 2 diabetes (UT2D) among adults (aged 18 years and older) in Iraq.
Design Cross-sectional, population-based study.
Setting Nationally representative sample of general community-dwelling adult population in Iraq from the 2015 Iraq STEPS survey.
Participants The sample included 3853 adults (mean age 41.8 years, SD=15.8), with complete fasting blood glucose values, from the 2015 Iraq STEPS survey.
Outcome measures Data collection included: (1) social and behavioural information, (2) physical parameters and blood pressure measurements and (3) biochemical measurements. UT2D was classified as not being diagnosed with T2D and fasting plasma glucose level ≥126 mg/dL. Multivariable multinomial and logistic regression was used to identify factors associated with UT2D.
Results The prevalence of UT2D was 8.1% and the prevalence of diagnosed T2D (DT2D) was 8.9%. Participants aged 50 years and older (adjusted relative risk ratio (ARRR): 2.11, 95% CI 1.30 to 3.43) and those with high cholesterol (ARRR: 1.54, 95% CI 1.05 to 2.24) had a higher risk of UT2D. Older age (≥50 years) (ARRR: 17.90, 95% CI 8.42 to 38.06), receipt of healthcare advice (ARRR: 2.15, 95% CI 1.56 to 2.96), history of cholesterol testing (ARRR: 2.17, 95% CI 1.58 to 2.99), stroke or heart attack (ARRR: 1.81, 95% CI 1.13 to 2.92), and high cholesterol (ARRR: 1.55, 95% CI 1.17 to 2.06) were positively associated with DT2D, and high physical activity (ARRR: 0.57, 95% CI 0.38 to 0.84) was negatively associated with DT2D. Higher than primary education (adjusted OR (AOR): 2.02, 95% CI 1.21 to 3.37) was positively associated with UT2D versus DT2D, while older age (≥50 years) (AOR: 0.12, 95% CI 0.06 to 0.25), healthcare advice (AOR: 0.45, 95% CI 0.29 to 0.70), and history of cholesterol screening (AOR: 0.37, 95% CI 0.24 to 0.58) were inversely associated with UT2D versus DT2D.
Conclusion Almost one in ten adults in Iraq had UT2D, and various associated factors were identified that could be useful in planning interventions.
- General diabetes
- EPIDEMIOLOGY
- Public health
Data availability statement
Data are available in a public, open access repository. The data source is publicly available at the WHO NCD Microdata Repository (URL: https://extranet.who.int/ncdsmicrodata/index.php/catalog).
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
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Strengths and limitations of this study
The study used a large, nationally representative community sample of adults of all ages in Iraq.
Two regression models estimating risk factors consisting of predisposing, enabling/disabling and need factors of undiagnosed type 2 diabetes (T2D), diagnosed T2D versus no T2D and undiagnosed T2D versus diagnosed T2D.
The study was limited due to its cross-sectional design, the use of some self-reported measures, and the non-inclusion of some potentially relevant variables, such as family history and awareness of diabetes.
Introduction
In 2019, 1.5 million people died from diabetes, although diabetes can be treated.1 If undiagnosed type 2 diabetes (UT2D) remains untreated serious morbidity2 3 and mortality4 5 may follow, emphasising the need for early diagnosis. Globally, almost half (44.7%) of the adult population with T2D had UT2D.6 In the general adult population of countries with lower resources, 4.9% had UT2D.7 For example, in Suriname, 39.6% of people with T2D had not been previously diagnosed,8 in northern Sudan among people with T2D 29.0% were newly diagnosed,9 in Basrah, Iraq, the proportion of UT2D was 11.0% (55.8% of total T2D),10 and among the Chinese adult population, the prevalence of UT2D was 6.9% (63.3% of total T2D).11 However, national prevalence data on UT2D in Iraq are lacking,12 which led to this study.
UT2D may be contextualised in terms of issues with healthcare use,13 14 including predisposing indicators (demographic characteristics), enabling indicators (enabling or limiting factors in relation to usage of healthcare) and need indicators (health services need).14 Predisposing indicators associated with UT2D included age (decreasing age,15–17 increasing age,13 18–20 lower among age ≥70 years vs 35–39 years21), male sex,16–18 living alone,17 22 marital or cohabitation status,22 ethnic minority,23 ethnicity24 and history of diabetes in the family.25 26 Enabling/disabling indicators correlated with UT2D consist of socioeconomic status,15 16 18 21 27 28 geolocation and region,13 15–17 healthcare usage frequency,17 health insurance status13 29 and lifestyle factors such as substance use and physical activity.12 19 21 30 Need indicators linked to UT2D consist of chronic conditions,13 such as hypertension,15 16 18 19 30 31 obesity,18–20 25 26 30 32 abnormal lipids26 32 33 and cardiovascular disease.16 19
The aim of the study was to assess prevalence and correlates of UT2D persons 18 years and older in Iraq.
Methods
Sample and procedures
The study analysed cross-sectional data from the 2015 Iraq STEPS survey,34 35 including those with fasting blood glucose values (response rate 93.0%).36 One person (≥18 years) was randomly selected from each household using multi-stage stratified sampling (urban–rural, primary sampling units=70 plus households, one household); inclusion criteria were at least 1 month residing in Iraq and exclusion criteria were temporary residence, displaced and institutionalised adults.36 Following the STEPS survey procedures, data collection included three steps: (1) social and behavioural information, (2) physical and blood pressure (BP) and (3) biochemical measurements.35 Blood glucose, total cholesterol (TC) and triglycerides were measured in peripheral (capillary) blood at the data collection site using dry chemical methods, biochemical analysis and automated analyser.36
Measures
Dependent variable
UT2D was classified as responding ‘no’ to the question ‘Have you ever been told by a doctor or other health worker that you have raised blood sugar or diabetes?’ and had fasting plasma glucose level ≥126 mg/dL; diagnosed T2D (DT2D) was defined as those who answered ‘yes’ to the question ‘Have you ever been told by a doctor or other health worker that you have raised blood sugar or diabetes?’.35
Predisposing indicators
Marital status, sex and age.
Enabling/disabling indicators
Healthcare advice, history of cholesterol testing, sedentary behaviour, physical activity and smoking history. Healthcare advice included, ‘During the past 3 years, has a doctor or other health worker advised you to maintain a healthy body weight or lose weight?’ (yes/no). Smoking history was asked with questions on current and past use of any tobacco products.36 Physical activity levels (low, moderate and high) and sedentary behaviour (≥8 hours sitting/day) were measured with the Global Physical Activity Questionnaire.37 38
Need indications
High TC, stroke or heart attack, hypertension and body mass index (BMI). Definitions were as follows:
BMI: underweight (<18.5 kg/m2), normal weight (18.5–24.9 kg/m2), overweight (25.0–29.9 kg/m2) and obesity (≥30.0 kg/m2)35; hypertension: systolic BP ≥140 mm Hg and/or diastolic BP ≥90 mm Hg and/or previously or current treatment with antihypertensive drugs39; stroke or heart attack: ‘Have you ever had a heart attack or chest pain from heart disease (angina) or a stroke (cerebrovascular accident or incident)?’ (yes/no)36; elevated TC: being on antilipidemic medication or having elevated TC: ≥5.17 mmol/L (200 mg/dL).40
Statistical analysis
All statistical analyses were conducted with STATA software V.14.0 (Stata Corporation) by taking the complex study design into account.36 Frequencies and percentage are used to describe the sample. Multinomial logistic regression was used to assess variables associated with UT2D and DT2D (reference category: no T2D). Binary logistic regression calculated associations with UT2D versus DT2D. Predisposing, enabling/disabling and need variables were included as covariates in the logistic regression models. Variables that turned out to be significant in univariate analyses were retained in the multivariable models. P values <0.05 were accepted as significant.
Patient and public involvement
None.
Results
Participant characteristics
The final sample included 3853 adults aged 18 years and older (M=41.8 years, SD=15.8 years) in 2015. The proportion of UT2D was 8.1% (47.6% of total T2D), DT2D 8.9% and total T2D 17.0%. More details are shown in table 1.
Characteristics of the sample (N=3853) according to type 2 diabetes (T2D) status in adults, Iraq, 2015
Associations with UT2D and DT2D versus no diabetes
In the final adjusted model, 50 years and older (adjusted relative risk ratio (ARRR): 2.11, 95% CI 1.30 to 3.43) and high cholesterol (ARRR: 1.54, 95% CI 1.05 to 2.24) were positively associated with UT2D. Participants ≥50 years and older (ARRR: 17.90, 95% CI 8.42 to 38.06), received advice from the healthcare provider (ARRR: 2.15, 95% CI 1.56 to 2.96), history of cholesterol testing (ARRR: 2.17, 95% CI 1.58 to 2.99), stroke or heart attack (ARRR: 1.81, 95% CI 1.13 to 2.92) and high cholesterol (ARRR: 1.55, 95% CI 1.17 to 2.06) were positively associated with DT2D, and high physical activity (ARRR: 0.57, 95% CI 0.38 to 0.84) was negatively associated with DT2D. In addition, in unadjusted analyses, past tobacco smoking, obesity and hypertension were positively associated, and high physical activity was negatively associated, with UT2D (see tables 2 and 3).
Unadjusted associations with undiagnosed type 2 diabetes (UT2D) and diagnosed (DT2D) in adults in Iraq, 2015
Adjusted associations with undiagnosed type 2 diabetes (UT2D) and diagnosed (DT2D) in adults in Iraq, 2015 (adjusted for all variables in the table)
Associations with UT2D versus DT2D
In the adjusted logistic regression model, higher education (adjusted OR (AOR): 2.02, 95% CI 1.21 to 3.37) was positive, 50 years and older (AOR: 0.12, 95% CI 0.06 to 0.25), healthcare advice (AOR: 0.45, 95% CI 0.29 to 0.70) and history of cholesterol tests (AOR: 0.37, 95% CI 0.24 to 0.58) were negatively associated with UT2D versus DT2D (see table 4).
Associations with undiagnosed type 2 diabetes (UT2D) versus diagnosed (DT2D) in adults in Iraq, 2015
Discussion
This national survey showed a prevalence of UT2D of 8.1% (47.6% of total T2D), which is higher than global figures (44.7%)6 and in lower resourced countries (4.9%),7 and higher than in Suriname (39.6%),8 in northern Sudan (29.0%),9 and China (6.9%, 63.3% of total T2D),11 but lower than in Basrah, Iraq (11.0%).10 In people with UT2D versus DT2D fewer diabetes-related comorbidities were observed, including the absence of obesity and hypertension as well as younger age. This finding may be explained by people with UT2D often at an earlier phase of T2D being generally healthier and younger than those with DT2D.12
According to previous studies,13 16–20 24 the predisposing indicator of increasing age was associated with UT2D versus no T2D. In addition, in unadjusted analysis, not married increased the odds of UT2D versus DT2D, which agrees with some previous studies.17 22
Consistent with some research,12 17 29 the disabling or enabling indicators higher education, high physical activity, no history of cholesterol testing and no recent healthcare advice (to lose weight) were associated with UT2D versus DT2D. Participants who use healthcare services more often through, for example, cholesterol testing and receiving health advice have greater chances of being screened for T2D and can become DT2D.13 Furthermore, compared with UT2D patients DT2D patients are expected to visit their healthcare provider more often according to the T2D management guidelines in Iraq.17 41 Consistent with some findings,18 21 we found that higher education was associated with UT2D versus DT2D. Unlike some previous research,13 15 this survey did not show a significant association between urban residence and DT2D. This could mean that rural adults have similar access to health services and similar risk factors for T2D than urban adults in Iraq.
In agreement with previous studies,13 26 32 33 need indicators (perceived need for health services) in terms of high cholesterol was associated with UT2D. Some previous research15 16 18–20 25 26 30–32 showed a correlation between hypertension and obesity with UT2D versus no T2D, while we found negative associations with UT2D versus DT2D. Only cardiovascular disease was positively associated with DT2D, which again may be explained by a higher likelihood of being screened for T2D when attending to healthcare for cardiovascular disease management.
Study strengths and limitations
Study strengths included the use of standardised STEPS assessment measures and the inclusion of a nationally representative sample of all adult ages. However, institutionalised adults were excluded from the survey. The study was limited due to its cross-sectional design, the dated data, the use of some self-reported measures and non-inclusion of some potentially relevant variables, such as family history and awareness of diabetes.
Public health implications
Intensified efforts are needed to increase awareness and screen for T2D in Iraq. The Iraq national non-communicable diseases policy emphasises public awareness campaigns, screening, early diagnosis and integrated care of T2D, strengthening the capacities of health workers in primary healthcare centres to provide advice regarding early detection of diabetes, and inclusion for first-line treatment for diabetes as essential medicines list for primary healthcare centres.42 In addition, an expert panel recommended further screening for diabetes and pre-diabetes across the various regions of Iraq, and that the Finnish Diabetes Risk Score is an appropriate screening tool for T2DM that should be made available to all asymptomatic patients across the country.41
Conclusion
Almost one in ten adults in Iraq had UT2D. Predisposing indicators, such as increasing age, and need indicators or perceived need for health services, such as high cholesterol, were identified as associated with UT2D versus no T2D, and decreasing age, higher education, and low healthcare service use in terms of healthcare advice and cholesterol testing, were found to increase the odds of UT2D versus DT2D, which can be included in improving uptake of early T2D detection.
Data availability statement
Data are available in a public, open access repository. The data source is publicly available at the WHO NCD Microdata Repository (URL: https://extranet.who.int/ncdsmicrodata/index.php/catalog).
Ethics statements
Patient consent for publication
Ethics approval
Ethics approval for the STEPS survey was obtained from the Republic of Iraq Ministry of Health/Environment Public Health Directorate and participants provided informed consent. Additional ethics approval was not necessary for the use of anonymised data from STEPS in the present analysis.
Acknowledgments
“This paper uses data from the Global School-Based Student Health Survey (GSHS). GSHS is supported by the World Health Organization and the US Centers for Disease Control and Prevention.”
References
Footnotes
Contributors All authors fulfil the criteria for authorship. SP and KP conceived and designed the research, performed statistical analysis, drafted the manuscript and made critical revision of the manuscript for key intellectual content. All authors read and approved the final version of the manuscript and have agreed to authorship and order of authorship for this manuscript. KP is the guarantor accepting full responsibility for the work and/or the conduct of the study, had access to the data, and controlled the decision to publish.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer reviewed.