ORIGINAL

Niger J Paed 2012; 39 (3): 128 – 132

Okpere AN

Anochie IC

Eke FU

Evaluation of microalbuminuria in

obese adolescents

DOI:http://dx.doi.org/10.4314/njp.v39i3.8

Accepted: 20th February 2012

lence of obesity to be 8.6%. Micro-

albuminuria was present in 23

(35.4%) of the 65 obese subjects

without overt proteinuria. The pro-

portional prevalence was higher in

females (42.9%), in age group 10-

Abstract Background: Obesity is a

risk factor for metabolic syndrome

with insulin resistance. Its effect on

renal and cardiovascular diseases is

reported in developed countries, but

rarely established among adoles-

cents in developing countries.

(

)

Okpere AN

Anochie IC, Eke FU

Department of Pediatrics,

University of Port Harcourt

Teaching Hospital,

1

4years (42.2%), in subjects with

hypertension (57.1%), and family

history of hypertension (50.0%) and

diabetes mellitus (37.5%) [p >

PMB 6173,

Port-Harcourt, Rivers State,

Nigeria.

E-mail: anokpere@yahoo.com

Tel: +2348059150818

Subjects and methods: A cross-

sectional study of 846 adolescents

selected from 12 secondary schools

in Port Harcourt, Nigeria. Obese

subjects with Body Mass Index

0

.05].

Conclusion: There is high preva-

lence of adolescent obesity, and a

high prevalence of microalbuminu-

ria among obese adolescents in Port

Harcourt. We recommend efforts at

reducing obesity as a means of pre-

venting renal disease in adolescents.

(

9

BM_t_hI) equal to or greater than the

5

percentile for age and sex on

the United States CDC growth chart

were selected and studied. Urine

samples of subjects without overt

proteinuria were tested for microal-

buminuria using the micral test

strips.

Key words: obesity, microalbumin-

uria, end stage renal disease, ado-

lescents, Nigeria

Results: Seventy-three of the sub-

jects were obese giving the preva

Introduction

In Africa, there are few reported studies on t₁h₀_,e₁₁ preva-

lence of obesity in children and adolescents. How-

Obesity is a major worldwide public health problem₁ ,

ever, there is paucity on data on the prevalence of micro-

albuminuria in obese adolescents. This study aims to

determine the prevalence of obesity and microalbuminu-

ria among obese adolescents in Port Harcourt, Nigeria.

,2

and its prevalence is increasing like an epidemic.

Obese children are at greater risk for type 2 diabetes

mellitus, cardiovascular and ren₃al damage/disease as

adolescents and also in adult life. These complications

are attributed to the widespread vascular endothelial

4

dysfunction in obese subjects. Microalbuminuria is a

marker of endothelial dysfunction and an indicator of

5

early damage to the kidneys and cardiovascular system.

Subjects and methods

Previous community-based studies in children in the

United States of America (USA) showed that over-

weight c₆h_,₇ildren had less microalbuminuria than leaner

A cross-sectional study of 846 students, aged 10 –

19years was conducted_t_hover a period of ei_t_hght weeks

between September 29 to November 10 2008 in

twelve (eight private and four public) secondary schools

in Port Harcourt City. Students with the following

conditions were excluded from the selection; those that

had vigorous exercise or competitive sport twelve hours

prior to the study, fever at the time of study or a history

of febrile illness two weeks prior to the study, symptoms

children.

However, studies from obesity clinics also

in the USA reported that among overweight children,

presence of various cardiovascular risk factors such as

diabetes mellitus, insulin resistance and hy₈_,p₉ertension

were associated with more microalbuminuria.

1

29

and signs suggestive of pre-existing renal disease,

female students who were menstruating or within one

week of cessation of menses or history of vaginal

discharge, and male students with of history urethral

discharge.

Results

Out of the 846 students recruited for the study, 73 sub-

jects were obese giving a prevalence rate of 8.6%. Table

1 shows the characteristics of the obese subjects. There

were 24 (32.9%) males and 49 (67.1%) females with a

M:F ratio of 1:2.0. Majority (72.6%) of the obese sub-

jects were aged 10 – 14 years. The mean age was 13.6 ±

2.1 years, and mean BMI was 30.9 ± 3.5kg/m . Majority

(68.5%) of the subjects were in private schools and

64.4% belonged to socio-economic classes 1 and II.

Ethical clearance was obtained from the Research and

Ethics Committee of the University of Port Harcourt

Teaching Hospital (UPTH). Permission was also

obtained from the Rivers State Ministry of Education,

principals of the selected schools as well as the selected

students and their parents/guardians.

2

Table 1: Characteristics of the Obese subjects

The study was carried out on school days in the various

schools. Obese subjects with Body Mass Index (BMI)

[

2 th

calculated as weight (kg) /height (m )] ≥95 percentile

Parameter

Number

49

%

for age and sex on the₂ United States sex-specific BMI-

Sex

1

for-age growth charts were selected and then studied.

A detailed history was obtained including family history

of diabetes mellitus or hypertension. The social class of

each subject was determined using the social

Female

Age group

67.1

(years)

1

3

classification described by Oyedeji. Hypertension was

1

0 - 14

5 - 17

8 - 19

53

16

4

72.6

21.9

5.5

defined as blood pressure greater than o₄ r equal to the

1

9

5th percentile for age, sex and height. Each subject

voided about ten milliliters (mls) of spot urine which

was shared into two universal containers (A) and (B). A

School Type

Private

Public

Social Class

50

23

68.5

31.5

dipstick urinalysis was performed on the urine sample

R

on container

A

using the Combi-Screen .10SL

manufactured by Macherey Nagel MN, Germany with

Lot number 56704. Presence of glycosuria in the

presence of polyuria, polyphagia or polydipsia was

suggestive of diabetes mellitus. However, the diagnosis

of diabetes mellitus was not confirmed with a fasting

blood sugar level because the investigators were not

permitted to collect blood samples from the students.

The subjects who were negative for proteinuria and

blood on dipstick urinalysis had their urine samples in

container B tested for microalbuminuria using the

Micral-test strips manufactured by Roche, USA with Lot

number 28989833. A reading of 20mg/L and above was

considered positive for microalbuminuria.

I

II

III

IV

V

40

7

13

12

1

54.8

9.6

17.8

16.4

1.4

Prevalence of Microalbuminuria in Obese Adolescents

Eight (11.0%) of the obese subjects had overt

proteinuria on dipstick urinalysis and were excluded

from further analysis. The remaining 65 (89.0%)

students were tested for microalbuminuria and analysed.

Microalbuminuria was present in 23 of the 65 obese

subjects giving a prevalence rate of 35.4%. They com-

prised of 5 (21.7%) males and 18 (78.3%) females. As

shown in Table 2, the proportional prevalence of MA

was higher in females (42.9%) although the difference

was not statistically significant (p = 0.089). Although,

MA was higher in subjects within age group 10 – 14

years (42.2%)), those in private schools (38.6%) and

those in socio-economic classes I and II (65.2%), the

differences were however not statistically significant (p

Data Analysis

Data from the study was analysed using the Statistical

Package for Social Sciences (SPSS) version 15.0. The

2

Chi- square (χ ) analysis, was used where appropriate

to test proportions. In all cases, a p value of < 0.05 was

regarded as statistically significant.

>

0.05).

1

30

Table 2: Characteristics of the Obese Subjects with and without Microalbuminuria

Characteristics

Microalbuminuria

Positive(%)

Microalbuminuria

Negative(%)

Total

No(%)

P value

Sex

Male

Female

5(21.7)

18(42.9)

18(78.3)

24(86.7)

23(100)

42(100)

0.089

Age group

(years)

1

0 – 14

5 -17

8- 19

19(42.2)

4(25.0)

0(0.0)

26(57.8)

12(75.0)

4(100)

45(100)

16(100)

4(100)

0.141

Type of School

Private

Public

17(38.6)

6(28.6)

27(61.4)

15(71.4)

44(100)

21(100)

0.581

0.807

Socio-economic class

I

II

III

IV

V

11(33.3)

4(57.1)

4(33.3)

0(0.0)

22(66.7)

3(42.9)

8(66.7)

1(100.0)

33(100)

7(100)

12(100)

1(100)

Factors associated with Microalbuminuria in Obese

Adolescents

Family history of Hypertension: Family history of

hypertension was documented in four (6.2%) of the

obese subjects. Microalbuminuria was present in two

(50.0%) of these subjects. The difference was not statis-

tically significant (p = 0.610). However, the odds of

microalbuminuria is higher in subjects with family his-

tory of hypertension (OR = 1.905; 95% CI = 1.905

(0.250 -14.501).

Table 3 shows the identified factors associated with mi-

croalbuminuria in the obese subjects.

Hypertension: Hypertension was documented in seven

(

10.8%) of the obese subjects. The proportional preva-

lence of microalbuminuria was higher in subjects with

hypertension (51.7%) compared to those with normal

blood pressure (32.8%). However, the difference was

not statistically significant (p = 0.233; odds ratio [OR] =

Family history of Diabetes Mellitus: Family history of

diabetes mellitus was documented in eight (12.3%) of

the obese subjects. The proportional prevalence of

microalbuminuria was higher in subjects with family

history of diabetes mellitus (37.5%). Though the differ-

ence was not statistically significant (p = 1.000), but

odds of having microalbuminuria was higher in subjects

with family history of diabetes mellitus (OR = 1.110;

95% CI = 0.240 – 5.133).

0

.365; 95% Confidence Interval [CI] = 0.074 – 1.799).

Possible Diabetes Mellitus: One (1.5%) subject had

features suggestive of diabetes mellitus (presence of

glycosuria, polyuria, polyphagia or polydipsia). This

subject also had microalbuminuria but the difference

was not statistically significant when compared to the

subjects without features suggestive of diabetes mellitus

(

p = 0.354).

Table 3: Factors associated with Microalbuminuria in Obese Adolescents

Factor

Microalbuminuria

Positive(%)

Microalbuminuria

Negative(%)

P value

Odds ratio (95%CI)

0.365 (0.074 - 1.799)

0.344 (0.245 - 0.482)

1.905 (0.250 -14.501)

1.110 (0.240- 5.133)

Hypertension

Normal BP

2

19 (32.8)

3 (42.9)

39 (67.2)

0.233

Possible DM

No features of DM

1 (100.0)

22 (34.4)

0 (0)

42 (65.6)

0.354

0.61

1

Fx of Hypertension

No Fx of hypertension

2 (50.0)

21 (34.4)

2 (50.0)

40 (65.6)

Fx of DM

3 (37.5)

5 (62.5)

No Fx of DM

20 (35.1)

37 (64.9)

Key: CI = Confidence Interval; DM = Diabetes Mellitus; Fx = Family history

1

31

Discussion

endo₃thelial dysfunction that leads to microalbuminu-

2

ria. However, in contrast to the present study, previous

The global increase in childhood obesity has triggered

intensive research on the development and p₅revention of

community-based studies in children in the United

States showed that overweight c₆h_,₇ildren had less micro-

albuminuria than leaner children.

1

obesity in children in the western world. The preva-

lence of obesity reported in the present study is lower

than the 17.4% reported among children aged 2 – 19

The finding of decreasing prevalence of microalbuminu-

ria with increasing age in the present study is supported

by a previous study which s₄howed that proteinuria de-

1

6

years in the United States of A₇merica and the 35%

1

prevalence reported in England. The higher prevalence

2

of obesity in the developed countries may be attributed

to sedentary life style and high consumption of un-

healthy fatty food by children and adolescents in these

countries. The prevalence of obesity in the present study

is how₈ ever comparable to the 7.5% reported by Charkar

creased with increasing age. This is in sharp contrast to

a previous study which reported a₂₁positive correlation

between microalbuminuria and age.

We observed in this study that females had higher

prevalence of microalbuminuria compared to males.

This observation is similar to the findings recorded by

1

et al among Lebanese adolescents in a similar develop-

ing country. It is however much higher than the 0 –

6

2

.5% prevalence in males and 0 – 4.3% prevalence in

Nguyen et al in obese adolescents. The cause of the

females of over₁weight and obesity combined reported by

gender disparity cannot be readily explained but there is

1

Monyeki et al in a study conducted in children aged 3

evidence that there is in₅creased rate of albumin₂₆uria in

2

–

10 years in a rural community in South Africa. This

females during puberty. In addition, Davis et al noted

may probably be because the study in South Africa was

conducted among younger children living in rural areas

unlike the present study were majority of the subjects

were from high socioeconomic class and attending pri-

vate schools in an urban area. Obesity is strongly associ-

ated with microalbuminuria, which is a risk marker of

progressive renal damage in₁₉p_,₂a₀tients with known renal

that females have significantly higher daytime but not

night time urinary albumin excretion compared to boys,

which may suggest a higher possibility of orthostatic

albuminuria in females.

disease and healthy subjects.

Glomerular hyperfiltra-

tion, hyperinsulinaemia with insulin resistance, low

grade inflammation and leptin found in obesity have

been₂₀postulated as possible mechanisms of renal dam-

age.

Conclusion

The prevalence of obesity and microalbuminuria in

obese Nigerian adolescents is high. We recommend ef-

forts at reducing obesity in children through regular ex-

ercises and changes in lifestyle. Furthermore, screening

of all obese adolescents for microalbuminuria should be

included as part of the school health programme to en-

able detection and so that appropriate interventions can

be commenced early to prevent rapid deterioration in

renal function and subsequent development of end stage

renal disease.

The prevalence of microalbuminuria of 35.4% among

obese adolescents in the current study is much higher

6

than the 8.9% by Nguyen et al and 10.1% by Burgert et

8

al in the United States of America. The smaller sample

size studied in the present study may have accounted for

this disparity. Also, the non exclusion of orthostatic pro-

teinuria in the subjects in the present study may be a

contributory factor to the high prevalence of microalbu-

8

minuria, but this is not absolute. While Burgert et al

Limitations of the Study

used first early morning urine in their studies to elimi-

nate orthostatic proteinuria in the subjects, Nguyen et

al , similar to the present study, used random urine sam-

ples of their subjects and reported a lower prevalence of

microalbuminuria.

These include inability to identify and exclude students

with orthostatic proteinuria and physiologic proteinuria

which may result from routine physical activity such as

trekking to school. The study also did not determine

those students with transient proteinuria because only a

single urine sample was tested for albuminuria.

6

This present study shows that microalbuminuria was

more prevalent in obese subjects with hypertension, pos-

sible diabetes mellitus, family history of hypertension

and diabetes mellitus. This finding is supported by pre-

vious studies which reported that presence of cardiovas-

cular risk factors such as hypertension, impaired fasting

glucose, insulin resistance, metabolic syndrome, high

triglyceride and low high density liproprotein (HDL)

cholesterol levels increased the risk of m₆_,i₁c₁r_,₂o₁albuminuria

Conflict of interest : None

Funding : None

Acknowledgement

We are sincerely grateful to the students of the following

schools in Port Harcourt- Government Girls Secondary School,

Comprehensive Boys Secondary School, Navy Secondary

School, Community Secondary School, Tantua High School,

Christian Council College, Stella Maris Secondary School,

Baptist High School, Holy Rosary Secondary School, Method-

ist Secondary School, Methodist Girls Secondary School and

Aladumo Secondary School for participating in the study.

in overweight and obese adolescents.

Obesity is

associated with increase intraglomerular cap₂illary pres-

2

sure resulting in glomerular hyperfiltration. Therefore,

the presence of hypertension and/or diabetes mellitus in

these obese patients may provide a second ‘hit’, causing

1

32

References

1

.

Norman J. Some Basic

10. Cameron N, Getz B. Sex

differences in the prevalence of

obesity in rural African

adolescents. Int J Obes Relat

Metab Disord 1997; 21:775-782.

11. Monyeki KD, van Lenthe FJ, Steyn

NP. Obesity: does it occur in

African children in rural

community in South Africa? Int J

Epidemiol 1999; 28:287-292.

12. United States National Centre for

Health Statistics in collaboration

for the National Centre for Chronic

disease Prevention and Health pro-

motion, 2000.

13. Oyedeji GA. Socio-economic and

cultural background of hospitalized

children in Ilesha. Nig J Paed.

1985;12:111-7.

14. Report of the second task force on

blood pressure control in children.

Pediatrics 1987;79:1-25.

15. Daniels SR, Jacobson MS,

McCrindle BW, Eckel RH, Sanner

BM. American Heart Association

Childhood Obesity Research Sum-

mit Report. Circulation 2009; 119:

e489-e517.

16. Overweight and Obesity. Atlanta,

Ga: Centers for Disease Control

andPrevention, US Department of

Health & Human Services.

Available at: http://www.cdc.gov/

nccdphp/dnpa/obesity/index.htm.

Accessed 27 November 2011.

17. Lobstein TJ, James WP, Cole TJ.

Increasing levels of excess weight

among children in England. Int J

Obes Relat Metab Disord 2003;

27:1136-1138.

19. PE de Jong, JC Verhave, SJ Pinto-

Sietsma, HL Hillege for the

PREVEND study group. Obesity

and target organ damage: the

kidney. Int J Obes Relat Metab

Disord suppl 2002; 26: 21 – 24.

20. Hall JE, Crook ED, Jones DW,

Wofford MR, Dubbert PM.

Mechanisms of obesity-associated

cardiovascular and renal disease.

Am J Med Sci 2002; 324: 127–137.

21. Unuigbe EI, Ighoroje AD,

Imariagbe FA, Alozie OK.

Considerations of Obesity as a

Public Health Problem. Am J

Public Health Nations Health

1

953;43(8): 989–992.

2

3

.

Caballero B. The global epidemic

of obesity: An overview.

Epidemiol Rev 2007; 29: 1–5.

Reilly JJ, Methven E, McDowell

ZC, Hacking B, Alexander D,

Stewart, et al. Health

consequences of obesity. Arch Dis

Child. 2003;88:748–752

Shankar SS, Steinberg HO.

Obesity and endothelial

4

5

.

Screening for microalbuminuria

amongst medical students in

University of Benin: a pilot study.

JMBR 2002; 1:29 – 33.

dysfunction. Semin Vasc Med

2

005; 5:56-64.

Verhave JC, Gansevoort RT, Hil-

lege HL, Bakker SJ, de Zeeuw D,

de Jong PE for the PREVEND

study group. An elevated urinary

albumin excretion predicts de

novo development of renal

22. Chagnac A, Weinstein T, Korzerts

A, Ramadan E, Hirsch J,Gafter U.

Glomerular hemodynamics in

severe obesity. Am J Physiol 2000;

278: F817–F822.

23. Nevon VD, Taal, MW, Sakharova

OV, Brenner BM. Multi-hit nature

of chronic renal disease. Curr Opin

Nephrol Hypertens 2000; 9:85-97.

24. Miltényi M. Urinary protein

excretion in healthy children. Clin

Nephrol 1979; 12: 216-21.

25. Bangstand HJ, Dahl-Jorgensen K,

Kjaersgaad P , Hanssen KF, Try K.

Urinary albumin excretion rate in

puberty in non-diabetic children

and adolescents. Acta Paediatr

1993; 82: 875-862.

26. Davies AG, Postlethwaite RJ,

Price DA, Burn JL, Houlton CA,

Fielding BA. Urinary albumin

excretion in school children. Arch

Dis Child 1984; 59:625-630.

function impairment in the general

population. Kidney Int suppl 2004;

6

6: 18-21.

6

.

Nguyen S, McCulloch C,

Brakeman P, Portale A, Hsu C.

Being Overweight Modifies the

Association Between

Cardiovascular Risk Factors and

Microalbuminuria in Adolescents.

Pediatrics 2008;121:37- 45.

Bangstad HJ, Dahl-Jorgensen K,

Kjaersgaard P, Mevold K,

Hanssen KF. Urinary albumin

excretion rate and puberty in non-

diabetic children and adolescents.

Acta Paediatr 1993;82: 857–862.

Burgert TS, Dziura J, Yeckel C,

Tasksali SE, Weiss r, Tambolane

W,et al. Microalbuminuria in

pediatric obesity: prevalence and

relation to other cardiovascular

risk factors. Int J Obes (Lond)

7

.

8

18. Chakar H, Salameh PR. Adolescent

obesity in Lebanese private

schools. Eur J Public Health

2006;16:648–651.

2

005;30:273–280.

9

.

Csernus K, Lanyi E, Erhardt E,

Molnar D. Effect of childhood

obesity and obesity-related

cardiovascular risk factors on

glomerular and tubular protein

excretion. Eur J Pediatr

2

005;164:44–49.