diabetes and impaired glucose tolerance in jordan: prevalence and associated risk factors

Journal of Internal Medicine 1998; 244: 317–323

© 1998 Blackwell Science Ltd 317

Diabetes and impaired glucose tolerance in Jordan: prevalenceand associated risk factors

K. AJLOUNI, H. JADDOU & A. BATIEHAFrom the National Centre for Diabetes, Endocrine and Genetic Diseases, Amman, Jordan and the University of Science and Technology, Irbid, Jordan

Abstract. Ajlouni K, Jaddou H, Batieha A (NationalCentre for Diabetes, Endocrine and Genetic Diseases,Amman, Jordan and the University of Science andTechnology, Irbid, Jordan). Diabetes and impairedglucose tolerance in Jordan: prevalence and associat-ed risk factors. J Intern Med 1998; 244: 317]323.

Objectives. To study the prevalence of diabetes melli-tus (DM) and impaired glucose tolerance (IGT) andtheir risk factors in Jordan.Design. A cross-sectional study in four Jordaniancommunities was conducted: Sarih in the north,Sikhra in the middle of the country, Mazar in thesouth and Subha-Subheih in the east. Within eachcommunity, a systematic sample of households wasselected. All subjects $25 years of age within theselected households were invited to participate in thestudy. A total of 2836 subjects were actuallyincluded in the study with an overall response rate of 70.5% (45% in males and 86% in females).World Health Organization criteria were adopted for the diagnosis of DM (fasting plasma glucose

$7.8 mmol L21 or plasma glucose of $11.1 mmolL21, 2 h after an oral anhydrous glucose load of75 g) and IGT (fasting plasma glucose ,7.8 mmolL21 and plasma glucose between 7.8 mmol L21 and11.1 mmol L21, 2 h after an oral glucose load of75 g).Results. The overall prevalence of DM was 13.4%:14.9% in males and 12.5% in females. IGT wasfound in 9.8% of the study population: 9.0% inmales and 10.3% in females. Factors independentlyrelated to DM using stepwise logistic regressionanalysis were sex, age, family history of DM, hyper-tension, hypercholesterolaemia (HC), and hyper-triglyceridaemia (HTG).Conclusion. Diabetes mellitus and IGT are commonamong adult Jordanians. Considering the high preva-lence of this sickness makes it imperative to formu-late a national plan to face this disease and itscomplications.

Keywords: diabetes mellitus, Jordan, prevalence &risk factors.

Introduction

Epidemiological studies in different populationsaround the world demonstrated a marked variationin the prevalence of DM and IGT among differentcountries, ethnic groups in the same country, anddifferences within the same ethnic group before andafter migration from their countries of origin to thenew world [1]. Contrary to the traditional belief thatDM is a disease of the rich and developed world, highprevalence rates of DM in the developing countrieshave been reported [2]. In the Middle East, reliabledata upon this subject are scarce. However, based onthe few available reports, the prevalence of DM is inthe range of 4]14% [3]14]. This variation may be

partly due to the use of different criteria for diagnosisrendering the comparison among these differentcountries a very difficult task. The purpose of thispaper is to report the first phase of a national surveyof DM and IGT and related risk factors in Jordan.

Country background

Jordan is a country with a population of 4.1 million.It has a small economy, chronic water shortages, lim-ited (5%) arable land, and must import virtually allenergy sources. The recent world-wide recession andthe Gulf War have adversely affected Jordan’s econo-my, resulting in a major decline in income, and anincrease in unemployment and poverty.

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© 1998 Blackwell Science Ltd Journal of Internal Medicine 244: 317–323

Study population and methods

The survey was conducted to estimate prevalenceand risk factors of DM; hypertension, obesity, smok-ing, HC, and HTG, in four semi-urban communities.The town of Sarih was selected from the north,Sikhra from the middle of the country, Mazar fromthe south, and Sabha-Subheih from the east border-ing the desert region. Selection of these towns wasbased on geographical distribution as well as onlogistic considerations such as the presence of ahealth centre in which to perform the study, and theavailability of accommodation for the study team. Ineach community, a systematic sample of households(every fifth house) after a random start was selected.All residents $25 years in the selected householdswere invited to participate in the study. A 2-memberteam (a male and a female) visited the household,explained the purpose of the study, and invited eligi-ble persons to report to the health centre at a givenday after an overnight fast. To encourage participa-tion, we contacted community and religious leaders,local clubs, schools, and the municipality to securetheir co-operation. To encourage employed people toparticipate, the study team worked in all week daysincluding weekends. Free transportation to and fromthe health centre was offered upon request.

In the health centre, a pilot-tested structured ques-tionnaire prepared specifically for the study wasadministered by a trained interviewer to collect infor-mation on socio-demographic factors as well as infor-mation on DM, hypertension, hyperlipidaemia, andsmoking habits, and their risk factors. Measurementsof height, weight, blood pressure, plasma sugar levels(both fasting and 2 h post a 75 g oral glucose load-ing), total cholesterol, HDL, LDL, and triglycerideswere also obtained for each subject.

A random sample of non-respondents was selectedand interviewed using the same questionnaire withthe addition of one question about the reason fornon-participation. Work outside the town was themain reason for non-participation. Comparison ofthis sample of non-respondents with the study sam-ple revealed no difference in the rate of previouslydiagnosed DM or family history of DM.

Blood pressure was measured using standardizedmercury sphygmomanometer. Hypertension wasdefined as a systolic blood pressure of $160 mmHg,diastolic blood pressure of $95 mmHg, or currentuse of antihypertensive medications [15, 16]. Body

mass index (BMI) was calculated as weight in kilosdivided by height2 in meters. Obesity was defined asBMI of $27 in men and $25 in women [12, 14, 17].DM was diagnosed according to the recommenda-tions of a WHO Study Group, that is: a fasting plas-ma glucose level of $7.8 mmol L21, or 2 h plasmaglucose level of $11.1 mmol L21 [18]. Impaired glu-cose tolerance was classified as a fasting plasma glu-cose , 7.8 mmol L21 and a 2 h plasma glucoseconcentration between 7.8 mmol L21 and 11.1 mmolL21 [18]. hypercholesterolaemia was defined as aserum cholesterol level of $6.2 mmol L21 [19].Hypertriglyceridaemia was defined as a serumtriglyceride level of . 2.2 mmol L21 [19]. Educationwas classified into illiteracy, 1]12 years of formalschooling, and . 12 years of formal schooling.Smoking refers to current regular smoking irrespec-tive of amount and duration of smoking. Fastingblood samples for all biochemical measurements andthe 2 h-post-prandial-glucose sample were drawn inplain tubes and centrifuged within 1 h. All biochemi-cal measurements were carried out in the same dayof blood collection and by the same team of laborato-ry technicians. Blood glucose was measured by theoxidase method, using a Hitachi analyser. Every 10th

sample was tested a second time to asses the correla-tion coefficient between duplicates tested which wasfound to be 0.991. Serum cholesterol and triglyceridelevels were measured enzymatically using commer-cial kits obtained from Boehringer Mannheim.

Statistical analysis

Descriptive and bivariate analyses were performedusing the Statistical Package for Social SciencesPersonal Computer (SPSSPC). Multiple logisticregression analyses were performed to test for theindependent effect of selected risk factors on diabetes.The odds ratio (OR) was the antilogarithm of theregression coefficient of an indicator term that corre-sponded to a certain level of the independent vari-able. The 95% confidence interval was calculatedusing the standard error of the regression coefficient.

Results

A total of 2836 subjects were examined, represent-ing an overall response rate of 70.5% (54% in malesand 86% in females). The response rate varied from45% in southern Mazar to 79% in Sikhra with a con-

DIABETES IN JORDAN 319


sistent pattern of over representation of females in allfour locations. The final study population consisted of1046 males and 1790 females.

Table 1 shows the prevalence of DM by a numberof variables. As expected, the rate of DM increasedwith age, from around 1% in the age group 25]29,to 15% in the fifth decade and 24% after the age of50 years. Women were more likely to have DM butthe difference was not statistically significant. Familyhistory of diabetes, hypertension, HC, HTG, and obe-sity were found to be significantly associated withdiabetes. Illiterate people were found to be at thehighest risk of having diabetes (20%) compared to

around 6% among those with education. A signifi-cant inverse trend was observed between educationand DM (P , 0.001). There was no statistically sig-nificant difference in the prevalence rate of DMamong the four communities.

Table 2 shows adjusted ORs of DM for a number ofvariables using stepwise logistic regression. All fac-tors in Table 1 were included in the model. Age, sex,family history of DM, HC, HTG, and hypertensionwere all significantly and independently related toDM. Obesity, Education, and smoking were not inde-pendently related to DM and therefore, were excludedfrom the model by the stepwise procedure. Separate

Table 1 Prevalence of diabetes mellitus by selected variables and significance of the associations, Jordan, 1997

Variable Population Diabetics % P

Total 2836 379 13.4

SexM 1046 156 14.9F 1790 223 12.5 ,0.07

Age ( years)25–29 0534 006 01.130–39 0627 021 03.440–49 0604 091 15.150–59 0537 128 23.860–69 0350 087 24.970–79 0124 033 26.6801 0034 005 14.7 ,0.001

BMI (kg/m2)M ,27, F ,25 0858 072 08.4M $27, F $25 1932 301 15.6 ,0.001

Family historyNo 1102 202 09.8Yes 1404 137 18.3 ,0.001

HypertensionNo 2243 235 10.5Yes 0416 102 24.5 ,0.001

SmokingNo 2383 323 13.6Yes 0438 052 11.9 ,0.38

HypercholesterolaemiaNo 1975 205 10.4Yes 0857 171 20.0 ,0.001

HypertriglyceridaemiaNo 2082 205 09.9Yes 0744 170 22.9 ,0.001

EducationIlliterate 1022 204 20.01–12 years 1437 151 10.5.12 years 0373 022 05.9 ,0.001

Variability in totals is due to missing data on some variables.



analyses were performed for males and females todetect any sex differences in the risk factors of DM.No such differences were observed.

The ratio of diabetics diagnosed before the studyand those discovered by the survey was 2:1. Theoverall prevalence rate of IGT was 9.8% with no sexdifference. The prevalence of IGT as demonstrated inTable 3 revealed significant association with age,family history of DM, hypertension, HTG, and educa-tion. No significant relation between IGT and smok-ing or hypercholesterolaemia was found.

Discussion

Our data demonstrate a prevalence rate of DM high-er than that reported from most countries in theregion. Table 4 demonstrates highlights of somestudies published from the Arabic countries. A com-parison of our data with these reports is difficultbecause of the different criteria used, the differentage groups studied, and the different methodologiesadopted.

In the present study, males were more likely to bediabetic than females after adjustment for a numberof potential confounders as shown in Table 2.Previous reports from the region were variableregarding gender differences in the prevalence ofDM. Our data are consistent with those reported fromSaudi Arabia [11], and Tunisia [13] but not withreports from Iraq [8] and Abu-Dhabi [4]. It is unlikelythat the gender difference observed in this study ismerely due to the lower response rate among malesalthough it could not be completely excluded for anumber of reasons. The main reason for this state-ment is that the same gender differences wereobserved in all locations irrespective of their responserates which varied from as low as 45% in southernMazar to as high as 79% in Sikhra. If men workingoutside the town were less likely to be diabetic and

less likely to participate in the study we would expectthat locations with low response would have a highergender difference in DM than areas with a betterresponse.

The percentage of subjects with diabetes diag-nosed in any particular survey not knowing thatthey have diabetes varies widely: while it is about50% in Europe and North America [1], it reached100% in the pacific population [1] and was less than50% in some industrialized communities [1]. Theratio in Jordan of diabetes diagnosed during the sur-vey to that known before the survey was carried outis 1:2. This may indicate an increased awareness ofthis disease.

While these alarming results in Jordan may comeas a surprise to many, they fit easily with the generalconclusion ] that populations who lived formerly in aharsh environment, developed through evolution athrifty genotype [20,21], which resulted in selectivesurvival advantage by allowing high efficient storageof calories in times of excessive supply. This advan-tage became detrimental when food supply becameconstant and abundant. Carter et al. [8] reported thatall minorities in the USA have prevalence of noninsulin dependent diabetes mellitus two to six timesgreater than that of white persons. They attributetheir finding to genetics, change in diet, lack of exer-cise and improved socio-economic standards. Wethink that these factors are behind the high preva-lence rate of DM in Jordan.

Obesity and education which were significantlyrelated to DM in the univariate analysis lost theirrelationship after adjustment to other factors in themultivariate analysis (Table 2). The apparent rela-tionship of obesity and education with DM was large-ly due to their association with gender, HC, and HTG.

What is remarkable in our study is the high preva-lence of IGT reaching around 10%. Many studiesdemonstrated beyond any doubt that patients with

Table 2 Factors independently related to diabetes mellitus using stepwise logistic regression, Jordan, 1997

Variable OR 95% CL P

Sex (M vs. F) 02.0 1.4–2.8 ,0.001Age ($40 vs. ,40 Y) 12.7 7.4–21.8 ,0.001Family history (Y vs. N) 02.5 1.9–3.3 ,0.001Hypercholesterolaemia (Y vs. N) 01.6 1.2–2.2 ,0.001Hypertriglyceridaemia (Y vs. N) 02.1 1.6–2.8 ,0.001Hypertension (Y vs. N) 01.6 1.1–2.1 ,0.01

Education, smoking, and BMI were excluded from the model by the stepwise procedure.



this disorder may already have cardiovascular riskfactors, with insulin resistance which leads to centralobesity and accelerated atherosclerosis [20]. Holman[21] has indicated that the prevalence of IGT variesamong different populations but is particularly highin communities in developing countries which haveadopted a western life style and we believe Jordan isone of these. Our data failed to demonstrate any dif-ference in IGT rates between men and womenalthough the reports of male: female ratio in IGTvaries widely across populations [22]. At present wehave no data on the progress rate of IGT to NIDDM[23], a follow-up study is certainly indicated. It is of

interest that HTG was a significant risk factor in DMand IGT. This was not the case with HC which hasrelevance in DM only and not in IGT.Hypertriglyceridaemia is a significant predictor ofsubsequent cardiovascular mortality in persons withdiabetes and IGT [24]. A study from Japan revealedsubjects with IGT to have higher triglyceride andblood pressure levels than a control group matchedfor age, sex, and BMI. Whatever the explanation forthe association, further studies are indicated to eluci-date, and further validate this observation [25]. Inconclusion with the high prevalence rates of the riskfactors; hypertension (15%) [16], HC (23%) [19],

Table 3 Prevalence of impaired glucose tolerance by selected variables and significance of the associations, Jordan, 1997

Variable Population IGT % P

Total 2531 249 09.8

SexM 0915 082 09.0F 1615 167 10.3 ,0.47

Age (years)25–29 0507 012 02.430–39 0602 037 06.240–49 0547 070 12.850–59 0443 056 12.660–69 0279 046 16.570–79 0099 014 14.1$80 0028 007 25.0 ,0.001

BMI (Kg/m2)M ,27, F ,25 0771 043 05.6M $27, F $25 1716 199 11.6 ,0.001

Family HistoryNo 1298 105 08.1Yes 0933 107 11.5 ,0.01

HypertensionNo 2041 167 08.2Yes 0338 071 21.0 ,0.001

SmokingNo 2118 217 10.3Yes 0395 030 07.6 ,0.24

HypercholesterolaemiaNo 1796 171 09.5Yes 0732 077 10.5 ,0.40

HypertriglyceridaemiaNo 1905 173 09.1Yes 0618 074 12.0 ,0.01

EducationIlliterate 0867 123 14.21–12 years 1310 101 07.7.12 years 0346 024 07.0 ,0.001

Variability in totals is due to missing values on some variables.



and HTG (24%) [19] in Jordan, and with improvedlife expectancy, we expect a significant increase in theprevalence of diabetes and its complications in thenext 20 years. This makes further research a nation-al priority in order to draft and implement a plan forthe primary and secondary prevention of diabetes.

Acknowledgements

This study was supported by grants from JordanUniversity of Science and Technology, MutahUniversity, Al al-Bayt University, HC ST, JU, WHO,and the Ministry of health of Jordan.

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Egypt [6] .10 Y WHO criteriaUrban — — 05.7Rural — — 04.1Desert — — 01.5Egypt [7] $20 Y WHO criteriaRural — — 04.9Urban (low SES) — — 13.5Urban (high SES) — — 20.5Iraq [8] 2.9 5.9 — $15 Y 50 gm OGTTOman [9] — — 10 $20 Y WHO criteriaSaudi Arabia [10] $18 Y FBS .7.2 mmol L21

Khaybar — — 16.5Hofuf — — 10.9Al-ula — — 09.8Najran — — 02.4Gizan — — 08.9Saudi Arabia [11] 5.5 3.1 04.6 .10 Y Capil.blood glucose

$200 mg% after noon mealSudan [12] 3.5 3.4 — 25 Y WHO criteriaTunisia [13] 4.6 3.5 — .20 Y FBS .165 mg%Tunisia [13] 9.2 9.1 — .30 Y WHO criteria

OGTT: oral glucose tolerance test.



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Received 26 November 1997; accepted 3 February 1998.

Correspondence: Dr Kamel Ajlouni, National Centre for Diabetes,Endocrine, and Genetic Diseases, Amman, Jordan, PO Box: 13165fax: 1832086).

diabetes and impaired glucose tolerance in jordan: prevalence and associated risk factors

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