ORIGINAL

Niger J Paed 2015; 42 (2): 137 –141

Jaja T

Yarhere IE

Risk factors for type 2 diabetes

mellitus in adolescents secondary

school students in Port Harcourt,

Nigeria

DOI:http://dx.doi.org/10.4314/njp.v42i2.13

Accepted: 11th February 2015

Abstract: Background: The

prevalence of Type 2 diabetes

mellitus (T2 DM) in children and

adolescents is on the increase,

therefore, prevention and early

detection are important.

tion criteria for identification of

those at risk for T2DM, 21(2.4%)

were identified. The frequency of

presence of risk factors was more

in females (3.3%), mid adolescent

age group (3.1%) and those with

positive family history of diabetes.

These findings were however not

statistically significant. There was

a statistically significant associa-

tion between presence of hyperten-

sion and impaired fasting glucose

and risk factor for type 2 DM.

Conclusion: The significant risk

factors identified in this study

were prehypertension/hypertension

and impaired fasting blood glu-

cose.

(

)

Jaja T

Yarhere IE

Department of Paediatrics,

University of Port Harcourt Teaching

Hospital. Rivers State, Nigeria

Email: Tamunopriyej@yahoo.com

Objective: To assess for easily

identifiable risk factors

(

overweight/obesity, hyperten-

sion, Impaired Fasting Glucose

IFG) and family history of diabe-

(

tes) for T2DM in adolescents in

public secondary schools

Result: Eight hundred and eighty

adolescents aged 10 to 19 years

were screened and 124(14.1%)

were overweight/obese. 457

(

51.9%) of students had none of

the risk factors while 272(30.9%)

had at least one risk factor. Using

the American Diabetes Associa-

Key words: Adolescence, Risk

factors, Type 2 diabetes mellitus

Introduction

light of increasing morbidity and mortality associated

with Type 2 DM in children , the American Diabetes

9

In the past, type 2 diabetes mellitus was considered as a

disease of adults . However, in the last decade, a world-

Association (ADA) developed guidelines to identify

children that are at risk and will require screening.

Based on these guidelines, children who are overweight

or obese and have any two of the following factors:

family history of type 2 DM, ethnic minority and signs

of insulin resistance or associated conditions

(hypertension, acanthosis nigricans, features of polycys-

tic ovarian syndrome, hypercholeste₁₀rolemia, and predia-

betes) should be referred for testing

1

wide increase in prevalence of type 2₂ diabetes in both

adults and children has been reported . The rise in the

incidence of type2 DM has mirrored the rise in preva-

lence of obesity in both developed and developing coun-

tries and this is attributed to a more sedentary lifestyle

3

and high consumption of refined foods . In a report by

The World Health Organization in 2003 in Geneva on

screening for type 2 DM, it predicted that there will be

at least 350million people in the world with type 2 DM

Type 2 DM is associated with chronic complications

such as micro vascular damage with end stage kidney

failure, blindness, and amputation which has huge finan-

cial cost. Early detection, prompt and adequate manage-

ment can prevent and halt progression of these compli-

cations. Studies on type 2 DM and risk factors for type 2

DM in African children are scarce. The aim of this study

is to report the prevalence of some easily identifiable

risk factors of type 2 DM amongst secondary school

students aged 10 to 19 years in Port Harcourt, Nigeria.

4

by the year 2030 .

There is paucity of information on the epidemiology of

type 2 DM in children in Nigeria. However, studies

mainly from America has shown that in children type 2

DM represents 8 to 45% of new cases and is commonly

diagnosed between the ages of 12 and 16 years₅a_,n₆ d in

those with positive family history of Type 2 DM. The

cause of type 2DM is multifactorial and include behav-

ioral, social and environmental factors which unmask an

7

underlying genetic susceptibility .

The susceptibility and risk factors for type 2 DM in chil-

dren has been fueled by the epidemic of obesity which is

8

now spreading even to the developing countries . In the

1

38

th

12

Methodology

95 percentile). Blood pressure percentiles based on

age and sex was also determined and classified into pre-

th

This report is based on a cross sectional study of secon-

dary school students in Port Harcourt. It is part of an

ongoing study on prediabetes in secondary schools in

Port Harcourt Local Government Area (LGA) of Rivers

State, Nigeria. It was carried out in 6 public secondary

schools over eight weeks, March to May, 2013.

hypertension (BP≥90 to <95 Percentile), hyperten_t_hsion

th

( ≥ 95 percentile) and normal blood pressure (< 90

1

3

percentile). Prehypertension and hypertension were

combined and analysed as hypertension.

Fasting blood glucose level of each of the participants

was determined following 8 to 10 hours overnight fast-

ing instruction, using the Accu-chek Active Roche Diag-

nostics glucometer. Results were classified based on the

ISPAD criteria into normal, impaired fasting glucose

and diabetic range glucose level. Impaired fasting glu-

cose (IFG) is defined by the ISPAD as fasting blood

glucose of 5.6 -6.9mmol/l (100 -125mg/dl). Accuracy

of the glucometers was checked each morning using the

Accu-chek control solutions.

Port Harcourt is the capital of Rivers State, a major in-

dustrial area of the Niger Delta region of Nigeria with a

huge oil exploration and urbanization. Rivers State has

an estimated population of 5.3million, using the 2006

1

census . The PH LGA is one of the largest local Gov-

ernment Areas in the State.

1

4

Ethical approval was obtained from the Ethics Commit-

tee of the University of Port Harcourt Teaching Hospi-

tal. Permission was obtained from the Rivers State

Ministry of Education and the head teachers of schools

selected. Assent and consent were also obtained from

students and parents, respectively.

Determination of risk factor for type 2 diabetes is as

described by the American Diabetes Association

1

0

(ADA). According to the ADA, children who are over-

weight or obese and have any two of the following fac-

tors: family history of type 2 DM, ethnic minority and

signs of insulin resistance or associated conditions

(hypertension, acanthosis nigricans, features of polycys-

tic ovarian syndrome, hypercholesterolemia, Prediabe-

Students aged 10 to 19 years were selected from six

public secondary schools in the Port Harcourt LGA,

using a multistage sampling from a list of 67 schools

categorized into three districts provided by the Rivers

state Ministry of Education a total of six public schools

with two each from each district were selected. Using a

prevalence of 50% due to the various risk factors consid-

ered, a minimum sample size of 1180 was recruited

from the three districts in a simple proportion for which

a total of 880 students met inclusion criteria and were

analyzed. We assessed four risk factors namely over-

weight/obesity, impaired fasting blood glucose (IFG),

hypertension and family history of diabetes. Plasma

cholesterol and triglyceride levels and evidence of poly-

cystic ovarian syndrome in girls were not assessed for

due to financial constraints.

1

0

tes) should be referred for testing .

All data were entered into an excel sheet and analyzed

using SPSS version 17. Results were presented in cross

tabulations and frequency tables. The age, sex, family

history of DM, hypertension and fasting blood glucose

status of adolescents at risk were compared with those

of their counterparts who are not at risk. Significance

level was determined by Pearson Chi square test and

Level of statistical significance was considered at P

value <0.05.

Data collection was carried out by the investigators and

trained field assistants who are medical officers of the

University Teaching Hospital.

Result

Of the 880 participants, 577(65.6%) were females. The

mean age of students studied was 15.01± 2.1 years.

There was no statistically significant difference between

the mean age of males (15.69±2.3) and mean age of fe-

males (14.65± 2.6). As shown in Table 1, 47.5% of the

participants were in the mid adolescent age group 13 to

15.9years. Overall 124(14.1%) of th_t_he students were

overweight and obese with BMI ≥ 85 percentile. The

highest prevalence of overweight was found among in-

dividuals with the following characteristics: females

17.7%, age between 13 and 15.9years 16.5%, IFG

21.1%, hypertension 22.8% and positive family history

of DM 18.2%. Among the participants, 99(11.2%) re-

ported positive family history of diabetes mellitus, 219

A pretested self-administered questionnaire was used to

obtain information on bio data, medical and family his-

tory of diabetes mellitus for recruited students. Standing

height was measured to the nearest 0.1cm using a wall

mounted stadiometer calibrated up to two meters.

Weight in Kg to the nearest 0.1Kg without shoes was

taken by an electronic weighing scale (Seca Alpha

Model 777). The scale was calibrated weekly and

checked for zero adjustment after each reading. Each

anthropometry was assigned specifically to two mem-

bers of the trained staff for uniformity and to avoid inter

observer errors. The fasting blood glucose levels of the

participants were determined.

(

24.9%) had prehypertension and hypertension and 152

The Body Mass Index (BMI) of each of the participant

was computed from the height and weight. Individual

BMI percentiles was determined for each subject based

on age and sex and categorized into underweight (BMI

(17.3%) had IFG.

Table 2 shows the distribution of risk factors among the

participants. Overall, about half 457(51.9%) of partici-

pants did not have any of the risks factor. Two (0.2%)

participants had all four risk factors that were assessed.

th th

5 percentile), normal weight (BMI> 5 percentile but

th th

<

less than 85 percentile), overweight (BMI ≥ 85 per-

th

centile but less than 95 percentile) and obesity (BMI ≥

1

39

Based on the ADA guideline, 21(2.4%) of the students

Table 3: Gender, Age, Blood pressure, Blood glucose and

Family history of diabetes by Risk group

1

0

were identified as at risk for type 2 DM . Table 3 shows

that there was no statistically significant gender differ-

ence in relation to presence of risk for type 2 DM. In

assessing the difference between the age groups, the age

At risk for

Type 2 DM

Not at Risk OR

(% of total)

P value

(% of total)

1

0 to 12.9 years was used as the reference group. There

Total

Gender

Male

Female

Age group

21(2.4)

858(97.5)

301(99.3)

was no significant difference found between the students

in the three age groups as shown in Table 3. Partici-

pants with family history of diabetes mellitus were more

likely to be at risk for type 2 DM; however this differ-

ence was not statistically significant. (p = 0.558). A

highly significant difference was found between partici-

pants with impaired fasting glucose compared with

those with normal blood glucose. (p<0.0001) A signifi-

cant difference was found for hypertension. (p<0.0001)

Children with prehypertension or hypertension were

2(0.6)

19(3.3)

558(96.7)

0.20

0.289

1

0-12.9

3-15.9

6-19

2(1.4)

13(3.1)

6(1.9)

137(98.6)

405(96.9)

317(98.1)

0.45

0.77

0.304

0.752

FH of DM

Negative

Positive

BP

Normal

Hypertension 16(7.3)

8(1.0)

13(13.1)

773(99.0)

86(86.9)

14.9

0.558

5 (0.8)

656(99.2)

203(92.7)

3

4% more likely to be at risk for type 2 DM.

10.34 <0.0001

Blood glucose

Normal

IFG

Children identified to be at risk for type 2 DM were

referred to the Paediatric endocrinology unit of the Uni-

versity Teaching Hospital for counselling and further

evaluation and follow up.

7(1.0)

14(9.2)

721(99.0)

138(90.8)

0.1

<

0

.0001

FH– Family history, BP-Blood pressure

Table1: Demographic Characteristics, Fasting blood glucose,

Blood pressure, and Family history of Diabetes mellitus and

overweight status of school children

Discussion

Variable

N (%)

Ove_tr_hweight (BMI

85 Percentile)

This study shows a low prevalence of risk factors for

T2DM in adolescents in public secondary schools in

Port Harcourt using the ADA criteria. This finding is not

consistent with rep₉o_,₁r₀t_,s₁₅from developed countries which

>

Age(yrs.)

1

0-12.9

3-15.9

6 -19

139(15.8)

418(47.5)

323 (36.7)

17(12.2)

69(16.5)

38 (11.8)

are usually higher

. In a study in Texas USA on

Gender

Male

Female

Fasting blood glucose

prevalence of risk factors for type 2 DM in children

aged 8 to 13 years, 22.6% of children aged 10 to 12

years we₉re at risk for type 2 DM according to the ADA

criteria, this was much higher than the 1.4% found in

children aged 10-12.9 years in our study. In Nigeria, no

study has been done on prevalence of risk factors for

Type 2 DM in adolescents. Studies in adults in Africa

have however shown that risk factors for Type 2 DM are

prev₆a_,₁l₇ent and the prevalence of Type 2 DM is increas-

303(34.4)

577(65.6)

22(7.3)

102(17.7)

Normal

IFG

Diabetic

Blood Pressure

Normal

Prehypertension/Hypertension 219(24.9)

Family History of DM

Positive

Negative

727(82.6)

152(17.3)

1(0.001)

92(12.7)

32(21.1)

0(0)

661(75.1)

74(11.2)

50(22.8)

1

99(11.2)

781(88.8)

18(18.2)

106(13.6)

ing . Reports on Type 2 DM in children and adoles-

cents in developing countries and in Africa is still

scarce, in a report in Sudan, prevalence of Type 2 DM in

children aged 11 to 18 years was 4%.The risk factors

common amongst the children with Type 2DM were

obesity, positive family history of diabetes and hyper-

IFG (Impaired fasting glucose), BMI (Body mass index), DM

(Diabetes mellitus)

Table 2: Distribution of participants according to number of

risk factors present

1

8

tension . In children, overweight is the risk factor most

9

Number of risk

factors present

Total (%)

strongly associated with the development of T2DM . In

Africa, there is a shift from underweight to overweight

along with rapid socioeconomic and₉n_,₂u₀tritional transi-

Male

Female

1

None

171

94

30

8

286

178

80

457(51.9)

272(30.9)

128(14.5)

21( 2.4)

tion particularly in urban population . In this study,

One factor

Two factor

Three Factors

Four Factors

14.1% of students were overweight and obese, higher

than earlier findings from Nigerian adolescents with sex

specific prevalence ranging between 0 to 8.1% for males

26

6

0

2( 0.2 )

21

and 1.3 to 8.1% for females . Also in a Systematic re-

view of evidence of overweight and obesity in school

aged children and youths in South Africa, a combined

prevalence of overweight and obesity was 13.1% similar

2

to the rate reported in this study . About 85% of chil-

dren with type 2 DM are overweight or obese with de-

velopment of insulin resistance and toxicity to beta cells

due to high levels of free fatty acids in obese

1

40

2

3

14

individuals .

cose based on the ISPAD criteria , 17.3% of the stu-

dents had impaired fasting glucose also referred to as

prediabetes. IFG is a feature of insulin resistance that

may eventually progress to diabetes mellitus. It is usu-

ally commoner in overweight adolescents as was seen in

this study where about a fifth of the adolescents with

IFG were overweight compared to 13% in normal

weight adolescents.

In this study, although the prevalence of those at risk for

Type 2 DM using the ADA criteria was low, prevalence

of individual risk factors and combination of risk factors

were worrisome. In this study, about a quarter of the

students had at least one risk factor and about 2.4% had

three risk factors and only 0.2% had four risk factors. In

a study done in Brazil amongst public secondary school

adolescents aged 12 to 17 years, 7.5% of students had

three risk factors and 1% had four risk factors . In an-

other study on risk factors for T2DM amongst adoles-

cents aged 12 to 17 years in private schools in Brazil the

prevalence of individual risk factors were higher than in

our study and the study in Brazil done in public secon-

dary schools showing that students from private schools

were more vulnerable to development of type 2 DM .

In America, a progressive increase in prevalence of

overweight and obesity noted over the years especially

in minority ethnic groups and people of low income

have been blamed for the increase in prevalence of Type

DM . The increase in weight is due to an improvement

24

There is need to avert the consequences of the increasing

incidence of Type 2 DM in children and adolescents,

research has shown that the higher the number of risk

factors, the higher the probability of acquiring the dis-

2

7

ease . In individuals with risk factors, it has been re-

ported that changes in lifestyle can reduce the chances of

progression to Type 2 DM by 58% over a period of 3

years. Such changes in lifestyle are aimed at reducing

and maintaining a normal weight, increased consump-

tion of fiber, restriction of fat, especia₈lly saturated fat

2

5

2

and increased regular physical exercise .

9

2

in standard of living experienced at this time. The low

prevalence rate therefore documented in this study may

be the beginning of the rise with better assess to energy

dense foods and transformation to more sedentary life-

style experienced in many developing countries in Af-

Conclusion

Conclusion The prevalence of risk factors for type 2 DM

according to the ADA criteria amongst students in Pub-

lic secondary schools in Port Harcourt, Southern Nigeria

was 2.4%. Prevalence of individual risk factors are of

concern and presence of one or more risk factors is

highly prevalent and seen in about half of the students

studied.

Considering the profile of risk factors recorded in this

study, there should be creation of awareness amongst

health workers and the general public and need for pub-

lic policies in schools, homes, health care centres to pre-

vent and control the increasing prevalence of these risk

factors.

1

6,17

.

rica such as Nigeria

Family history of diabetes mellitus is a very important

risk₈_,f₂a₆ctor for development of Type 2 Diabetes melli-

1

tus . Data from our study show that approximately

one out of every ten participant had a positive family

history of DM. In this study, although more students

with family history of DM were at risk for type 2 DM,

this was not statistically significant. The finding in this

report is however much lower than the report from the

Brazilian study where about half of the children studied

had a positive family history which may have accounted

2

4

for the higher prevalence of risk factors .

Conflict of interest: None

Funding: None

Other risk factors evaluated were blood pressure and

fasting blood glucose levels. In this study, about one

quarter of the students had prehypertension and hyper-

tension; although this is a concern, however the rate may

partially be accounted for by the anxiety created by the

study amongst the students and there is need for follow

up. In the study on Type 2DM in Sudanese children and

adolescents, more than fifty percent of the adolescents

Acknowledgement

We would like to say thank you to all medical officers

who assisted in data collection, the students and school

teachers of the various schools for their participation in

this study.

1

8

with Type 2 DM had hypertension . A considerable

percentage of the children also had impaired fasting glu-

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