Risk Factors of Gestational

Diabetes Mellitus in

Gombak District, Selangor –

A Case-Control StudyA Case-Control Study

By

Dr Siti Rohana Saad

MBBS (MAHE), MPH (UM)

Family Health Development Unit, Public Health Division, Selangor State Health Department

Outline

• Introduction

• Problem Statement

• Rationale of Study

• Methods

• Results

• Discussion

• Recommendations

• Conclusion

2

Introduction

• Gestational Diabetes Mellitus (GDM)

– Definition 1,2,3

– Represents most common metabolic

complication during pregnancy; earlycomplication during pregnancy; early

manifestation of type 2 diabetes 4,5

– Certain characteristics (risk factors) in the

women may predispose to development of

GDM during pregnancy 3,6

3

Problem statement

• Prevalence of GDM varies from 1-14% betweencountries1,4,6; varies in direct proportion toprevalence of type 2 diabetes in a given population7

• In Malaysia– Diabetes prevalence (among adult ≥ 30yrs of age)– Diabetes prevalence (among adult ≥ 30yrs of age)

had increased from 8.3% to 14.9% (1996 to 2006)8

– Diabetes admission based on type of diabetes (1994-2004): GDM represent ≈ 30% of total admission9

– GDM prevalence:

�1993 (UMMC):12.7%10

� 2001 (HUKM): 24.9%11

� 2003 (Alor Star): 18.3%21

4

• GDM was the cause for 90% of all pregnancies

complicated by diabetes22

• Associated with maternal and foetal morbidity 4,5

• High proportion (>50%) have GDM in the

subsequent pregnancy23

Problem statement (cont)

• Associated with an increased risk of subsequent

type 2 diabetes mellitus.

– approximately 50% of the women with GDM

progressed to DM within five years duration7

– 35-60% of women developed type 2 diabetes within

10 years after being diagnosed with GDM3

5

Rationale of Study

• Literature search done showed scarcity ofpublished article on study done in relation to GDMin this region

• Previous study done mostly at referral andspecialised unit – results may not represent thetrue picture of the diseasetrue picture of the disease

• Identification of GDM risks factors will provideinformation in strengthening public healthmeasures & prevent complications (maternal,foetal, development of overt diabetes &cardiovascular)

6

Study Objectives

• General Objectives– To determine the risk factors of GDM in Gombak

District, Selangor.

• Specific Objectives1. To describe socio-demographic and obstetric

characteristics of pregnant women with GDM.characteristics of pregnant women with GDM.

2. To determine the magnitude of associationbetween the socio-demographic and obstetriccharacteristics with development of GDM

3. To determine the independent risk factors of GDMamong pregnant women in Gombak District,Selangor

7

• Study design

– Case –control study (1:1)

• Study duration

– June 2007- February 2008

• Study population

– Pregnant women who had antenatal visits at MCH

Methods

– Pregnant women who had antenatal visits at MCH

clinics of Gombak District, Selangor.

• Case

– Pregnant women diagnosed with GDM using 75gm

OGTT : 2hpp plasma glucose level ≥ 7.8 mmol/l

• Control

– Pregnant women without GDM sampled from the same

clinic on the same day each case was identified

8

Location of Study Area - Gombak District of Selangor State

Land area

65,008 ha

Total land area

796,084 ha

9

Methods of data collection

1. Face to face

interview

• Single interviewer

• Pre-tested standardised

structured questionnaire

� Socio-demographic

2. Weight measurement• Using weighing machine

existing in the clinic

3. R/V of antenatal records

• Secondary data

� BMI, excessive � Socio-demographic

characteristics

� Obstetric

characteristics

• Past-obstetric

history

• Present Obstetric

history

� BMI, excessive weight gain, FBS, 2-HPP blood sugar, Urine sugar

• Additional information

� Medical history, Family History Countercheck information

10

Variables

• Dependent variable

� Gestational Diabetes

Mellitus

• Independent variables

� Socio-demographic

Age, ethnicity, educational

� Obstetric characteristics

1. Past-obstetric

history

LSCS, Big baby, GDM,

IUD, NND, Abortion,

Congenital defect, Age, ethnicity, educational

level, household income.

� Life style

BMI, excessive wt gain, Hb

level

� F/H of DM

Congenital defect,

Prematurity, Gest.

Hypertension

2. Present obstetric

history

Glycosuria, PV

discharge, Pruritus

vulvae, UTI, Gest.

Hypertension

11

Factors associated with GDM

Characteristics Non-GDM

(n-337)

GDM

(n-337)

Crude OR

(95% CI)

Maternal Age

(yrs)

< 25

25 – 35

>35

93 (27.6%)

214(63.5%)

30(8.9%)

35 (10.4%)

200 (59.3%)

102(30.3%)

Ref

2.48 (1.61, 3.83)

9.03 (5.15, 15.86)

Income

(RM)

< 2000

≥2000

162 (48.1%)

175 (51.9%)

134 (39.8%)

203 (60.2%)

Ref

1.40 (1.03 , 1.90)

Prepregnant

BMI

(Kg/m²)

< 18.5

18.5-24.9

25.0-29.9

≥30.0

49 (14.5%)

180 (53.4%)

77 (22.9%)

31 (9.2%)

17 (5.1%)

144 (42.7%)

90 (26.7%)

86 (25.5%)

Ref

2.31 (1.27 , 4.18)

3.37 (1.79 , 6.33)

7.99 (4.02 , 15.91)

Factors Associated with GDM

Characteristics Non-GDM

(n-337)

GDM

(n-337)

Crude OR

(95% CI)

P/H LSCS No

Yes

310 (92.0%)

27 (8.0%)

289 (85.8%)

48 (14.2%)

Ref

1.91 (1.16 , 3.14)

P/H

Abortion

No

Yes

291 (86.4%)

46 (13.6%)

262 (77.7%)

75 (22.3%)

Ref

1.81 (1.21 , 2.71)

P/H of Big

baby

No

Yes

333 (98.8%)

4 (1.2%)

312 (92.6%)

25 (7.4%)

Ref

6.67 (2.30 , 19.38)

H/O

Glycosuria

No

Yes

335 (99.4%)

2 (0.6%)

323 (95.8%)

14 (4.2%)

Ref

7.26 (1.64 , 32.20)

Factors Associated with GDM

Characteristics Non-GDM

(n-337)

GDM

(n-337)

Crude OR

95% CI

H/O excess.

Weight gain

No

Yes

208 (61.7%)

129 (38.3%)

112 (33.2%)

225 (66.8%)

Ref

3.21 (2.35, 4.40)

H/O

Gestational

Hypertension

No

Yes

322 (95.5%)

15 (4.5%)

298 (88.4%)

39 (11.6%)

Ref

3.24 (2.36, 4.44)

H/O PV

discharge

No

Yes

291 (86.4%)

46 (13.6%)

264(78.3%)

73 (21.7%)

Ref

1.75 (1.17, 2.62)

H/O Pruritus

vulvae

No

Yes

297 (88.1%)

40 (11.9%)

278 (82.5%)

59 (17.5%)

Ref

1.58 (1.02, 2.43)

Independent risk factors for GDM

Characteristics Adjusted OR (95% CI)

Maternal age

(Years)

< 25

25 – 34

≥35

Ref

2.03 (1.22 , 3.37)

11.95 (6.13, 23.29)

Pre pregnant BMI

(kg/m2)

< 18.5 Ref

(kg/m2) 18.5-24.99

25.0-29.99

≥30.0

1.18 (0.59 , 2.35)

1.37 (0.66 , 2.85)

3.71 (1.38, 6.76)

Household Income

/month (RM)

<2000

≥2000

Ref

1.49 (1.02 , 2.18)

Family History of

DM

No

Yes

Ref

3.62 (2.44, 5.36)

Independent risk factors for GDM

Characteristics Adjusted OR (95% CI)

P/H of GDM No

Yes

Ref

3.41 (1.37 , 8.51)

P/H of Big baby No RefP/H of Big baby No

Yes

Ref

5.83 (1.77 , 19.20)

H/O Exc. vaginal

discharge

No

Yes

Ref

2.25 (1.39 , 3.65)

H/O Excessive

weight gain

No

Yes

Ref

3.95 (2.69, 5.80)

Discussion

• Socio-demographic

– Maternal age ≥ 25 yrs and the odds increases as age

≥ 35 yrs with OR and 95% CI of 2.48 (1.61, 3.83) &

9.03 (5.15, 15.86) respectively 11,13, 15, 16, 19

– Gravidity – the odds was 2.56 x higher in multigravid

women (1.66, 3.94) 13, 16women (1.66, 3.94)

– Economic status – The odds was 1.40x higher in

higher household income → supported by other

study16 but other studies 14, 15 were contradicting

• Lifestyle

– Pre pregnant BMI – odds ↑ as BMI ↑, highest in

obesity (7.99: 4.02, 15.91) 13, 15, 16, 19

– Excessive weight gain – OR: 3.21 (2.36, 4.44)18

17

Discussion (cont)

• Obstetric Characteristics– Previous H/O GDM 11, 17

– Previous H/O Big baby 15, 16

– Previous H/O LSCS 16

– Previous H/O Abortions 11, 15, 16

– H/O glycosuria 15

– H/O gestational hypertension 15, 20

– H/O excessive vaginal discharge– H/O excessive vaginal discharge

• Independent risk factors– This study confirms results from the previous studies that risk

factors for GDM are:

• Maternal age 11,13, 15, 16, 19; Pre pregnant obesity 13, 15, 16, 19;Excessive weight gain 18; Family history of DM 15, 17, 18, 19;Previous history of GDM 11,17; Previous history of big baby 15, 16

• Higher income16 and excessive vaginal discharge

18

Strength of study

• Case and control group were comparable since they

came from the same population – pregnant women

from the same clinic

• High responds rate – as the respondents were not put

into any risk and not subjected to any inconvenienceinto any risk and not subjected to any inconvenience

of OGTT

• Study was done in Government Maternal and Child

Health Clinics which covers almost 80% of antenatal

population of the - Community Based

19

Limitation

• The study design – temporality cannot be ascertained

• Information bias– Respondents are subjected to recall bias

– Interviewer bias in getting information

– Steps taken:

• compared information from the antenatal records

• Single interviewer – reduced inter observer bias

• Selection bias– In selecting controls and cases – based on presence of risk factor/s– In selecting controls and cases – based on presence of risk factor/s

• Measurement bias– Weight measurement not properly done or weighing machine not properly

calibrated

– In defining cases – false positive/ negative result of plasma glucose level

• Confounding bias– Confounders are statistically controlled by subjecting variables to multiple

logistic regression

• Generalizability– Result of study can only be generalised to the antenatal population

attending the government health clinics

20

Recommendation

• Having GDM registry at periphery and the central level

• Considering maternal age ≥ 25 yrs, exc. vaginal discharge

for OGTT

• Concerted effort, multidisciplinary approach in preventing

and managing GDM

– Antenatal services– Antenatal services

– Pre marital health care programme

– Strengthening of family planning programme

• Strengthening the promotive and preventive health care in

tackling the lifestyle factors associated with GDM

• Policy on universal screening of GDM using GCT

21

Conclusion

• Development of GDM is associated with presence of

risk factors

• Strong and significant association between GDM and

the identified independent risk factors in this study

warrants serious attention in its prevention andwarrants serious attention in its prevention and

management prior to and throughout pregnancy

• Screening of GDM using risk criteria should consider

– Maternal age ≥ 25 yrs

– Presence of excessive vaginal discharge in indexpregnancy

22

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