4-Vafai

JRHS 2008; 8(1): 25-32

Copyright © Journal of Research in Health Sciences

Case-Control Study of acute diarrhea in Children

Vafaee A (PhD)a, Moradi A (MSc)b, Khabazkhoob M (MSc)b

a Department of Health and Management, School of Health and Paramedical Science, Mashhad University of Medical Science, Iran

b Department  of laboratory science technology, School of Health and Paramedical science, Mashhad University of Medical Sciences, Iran

*Corresponding author: Dr Ali Moradi, E-mail: moradia @mums.ac.ir,

Received: 27 September 2007; Accepted: 17 Jan 2008

Abstract

Background:  To determine the risk factor for acute diarrhea disease in children.

Methods: In the survey, 220 cases and 220 controls were involved. Cases were children with loose wa­tery feces, pathologically diagnosed as acute diarrhea by the physician, and enrolled from the Emer­gency Ward as the Incident Cases in Dr. Sheykh Hospital, Mashhad, northeast of Iran. Control group too, was enrolled from the same cases and the members were children whose risk factors dis­ease were not the risk factor for acute diarrhea, and were enrolled from emergency ward of burn pa­tients, accidents, acute respiratory diseases and eligible patients.

Results: By using univariate logistic regression models, variables consisting used milk up to 6 months age, antibiotic usage during the last 15 days, mother's employment, mother's acquaintance with ORS, oc­cupancy, and  water slack during the week before illness, were significantly related with acute diar­rhea. In a multiple logistic regression, the relationship between the said factors as the independent vari­ables and acute diarrhea was studied. Use of formulas before 6 month age with (95% CI 1.77-5.79) OR=3.21, and tenantry with (95% CI 1.24-2.71) OR=1.83, and mothers employment with (95% CI 1.2-5.06) OR= 2.48 were factors affecting acute diarrhea which remained in the multiple logistic model and had significant relationship with the disease.

Conclusion: During this study, important environmental risk factors were recognized. Endangered groups and mothers with children under 5 years old should be aware of these risk factors in order to pre­vent their children's diseases. Prevention of acute diarrhea in children can reduce massive detri­ments to health system.

Keywords: Acute Diarrhea, Case Control study, Children

Introduction

Several methodological issues may have an im­pact on the incidence rates of childhood acute diarrhea (A06.0) reported by commu­nity-based studies (1). In addition, it remains a major cause of childhood morbidity and mortality worldwide (2). In developing coun­tries, acute infectious diarrhea remains one of the leading causes of death among young children, especially those under 1 yr of age. In contrast, in industrialized na­tions the death rate is very low, although the disease is an important cause of morbidity and consumes substantial healthcare costs (3). According to Kowzak et al. from 60 re­searches during 1990 to 2000 it was deter­mined that cause of 21% of mortalities of chil­dren < 5 yr old was acute diarrhea and about 2.5 million mortali­ties were occurred be­cause of acute diarrhea annually and this showed the unchanged mor­bidity of this dis­ease comparing last decades (4). In year, 2000 Mory et al. also estimated that 13% of mortalities < 5 yr old were be­cause of diar­rhea that causes 1.4 million deaths each year (5). In comparison between two above re­searches, the decreasing rate of mor­tality and morbidity can be observed but still the im­portance of this disease determines it as a priority in some communities. Probabil­ity of diarrhea infection in infants is 4.8 in average yearly. Generally, in developing coun­tries the probability of diarrhea, infection is es­timated that for each child would be at least 3.2 times a year. This statistics in some develop­ing countries with a lower level of health con­dition is increases up to 9 cases (6). Ac­cording to the importance of acute diar­rhea in children health, different studies were con­ducted to identify the risk factors of this disease worldwide; by case-control study of Huffman et al. in Brazil, it is determined that the mortality caused by acute diarrhea among children who didnt use mother's milk are 25 times more than other chil­dren (7). Also in a case-control study for some factors of acute diarrhea in south Paki­stan, females were re­cruited for the risk fac­tors of acute diarrhea and the increase of moth­ers as well as chil­dren's age were identi­fied as a con­servational factor in diar­rheal patients (8). By Huttly et al. study in Ni­geria factors like: ingestion of contami­nated water, disregarding health of resi­den­tial environment, poor eco­nomi­cal status and nourishing milk powder are determined as risk factors of acute diarrhea (9).

According to limited studies in the field of studying risk factors of acute diarrhea in our country it is considered to design a study for some factors which has not investigated the di­rect relation of risk factors with diarrhea dis­ease till now so the aim of this study was to determine the relation of some demo­graphic and environmental factors related to life circumstances with acute diarrhea dis­ease in children of Mashhad. Maybe by identi­fying these factors we can truly de­crease the access of this disease.

Methods

This case-control study investigated children < 5 yr old. After presenting child accompa­nying parents or other person to emer­gency ward in Dr Sheykh Hospital, Mashhad, northeast of Iran this Hospital, chil­dren who had three loose and watery stools within 24-h period for last 3 days with determination of specialist as an acute di­arrhea, were enrolled as cases. Children with­out acute diarrhea and their identified cause disease was not the risk factor of investi­gated disease, were enrolled as con­trols. Under 5 age and permanent re­sides in Mashhad were the matched variables in both groups. Matching method was a kind of fre­quency matching.

After under-5, second measure for controls and enrollment in study was not being diar­rheal during last 6 months. Sampling for en­rollment of controls was according to the measures of cases. Cases were enrolled from patients presented to emergency ward and con­trols were enrolled from emergency ward of burn patients, accidents, acute respiratory diseases, and eligible patients. Control chil­dren were investigated and acute diarrhea was rejected. Having enrolled the cases and controls, information needed were collected through a questionnaire involved investi­gated variables.

It is important to say that the opinion of pro­fessional professors was used for determin­ing of validity of questionnaire and reliabil­ity were confirmed by means of test pretest method among 10 selected individuals with 82% index Cronbach Alfa.

According to the type of study and one of pri­mary aims of this study which was compar­ing the lack of nourishment rate of mother's milk till six months of age between controls and cases, volume of samples was de­termined according to this fact that if the nourishment rate of mother's milk in cases were 16% lesser than controls, to reject the hy­pothesis of ineffective nourishment of mother's milk till 6 months of age in diar­rheal episode in a two range test with error level of= 0.05) and power of (1-β= 0.80). According to this fact that there is not any reli­able information to examine the relation of mother's milk nourishment till 6 months of age on acute diarrhea and concerning some cultural differences of our country and developed countries and limitations of using their results, in a random process the rate of nourishment of mother's milk in cases were considered 50% and in controls 16% more and concerning 5% confidence level and power of 80%, 216 person were selected in each group.  In order to use random methods these samples were selected by systematic method in which at odd days recruit cases en­rolled with even file number and at even days recruit odd file number.

Parents testimonial was taken before enroll­ing each child to take their agreements. All of the information about children was gath­ered without name and surname by the number of file and the executive of this pro­ject pledged morally in testimonial to keep the information confidential.

According to type of this study odds ratio was used to convey the power of relationship which was estimated by logistic regression sin­gle-model. For more precise analysis, identi­fying and separating the manipulators from logistic regression multi-model with backward method. Descriptive indexes and charts of frequency distributions were used to describe other information.

Results

Considering sample, 229(52%) cases were male at the age between 1 month to 60 months and their average age was 19.35 yr. In both sexes the chance of diarrhea infec­tion, statistically was not significant. The aver­age ages in case group and control group, respectively, were 18.58 yr (95%, CI=16.66-20.50) and 20.13 yr (with 95%, CI= 17.99-22.27) which the average age differ­ence in both case and control groups sta­tistically was not significant. After omis­sion of sex impact, this relation turned to be significant as the chance of diarrhea infec­tion of boys is significantly decreased by in­creasing in age (P<0.05). Age distribution in both case and control groups according to sex presents in chart 1.

Figure 1: Distribution of case and control by age

After evaluation of relation between inde­pend­ent variations and acute diarrheal dis­ease with logistic regression models, these results were separately obtained; 16.8% of case group and 15.5% of control group had weight < 2500gr at the commence­ment of the birth which the under­weight difference this time in both groups was not statistically significant. Although there was not statisti­cally significant differ­ence in both case and control groups regard­ing consumption of refrigerated stale food dur­ing one weak before affection but 11% of case group and 6.8% of control group con­sumed refrigerated stale food.

The relation of acute diarrhea with variations like parent's education, water pressure fall, traveling during two weeks before affection, family size, and having vendor's food 10 days before affection was reviewed which the relation of none of these variations with acute diarrhea was significant. The con­sump­tion of milk powder in case group be­fore six months of age clearly was more than control group which had significant differ­ence in both groups (P<0.001). Mother's employment was a factor of significantly in­crease in the chance of diarrhea infec­tion (P<0.013). Indeed, after more precise sur­vey it was defined that day nursery as a de­facing factor demonstrate consequent rela­tion of affection and mother's employee weak, for this reason that children who have operative mothers spend their time in day nurs­ery more than other children. Role of mothers' lack of knowledge of ORS powder consump­tion in rising the chance of acute diar­rhea infection was significantly higher in case group (P<0.001). Taking antibiotics, lodg­ing and water stoppage one weak before af­fection were the factors which were signifi­cantly more in case group than control group (P<0.05). Table1 shows frequency distri­bution of case and control groups regard­ing effective cause of acute diarrhea. In one logistic regression multi-model the rela­tion between mentioned factors as inde­pendent variations and acute diarrheal dis­ease was reviewed in which milk powder con­sumption before six months of age, resi­dence status and mother's employment re­mained as effective cause in this model.

Table 1: Distribution of case and control by risk factors


Case

Control


n

%

n

%

Used milk up to 6 month age

Milk

171

77.7

202

91.8

Powder Milk

49

22.3

18

8.2

Antibiotic usage during the last 15 days

Yes

80

36.4

59

27.2

No

140

63.6

158

72.8

Mother's employment

Yes

26

11.8

13

5.9

No

194

88.2

207

94.1

Mother's  acquaintance with ORS

Yes

73

66.8

130

39.5

No

147

33.2

85

60.5

Occupancy

Landlord

98

44.7

130

59.4

Tenant

121

55.3

89

40.6

Water slack during the week

Yes

85

38.8

109

49.5

No

134

61.2

111

50.5

Having vendors food

Yes

11

5

9

4.1

No

209

95

210

95.9

Refrigerated stale food

Yes

22

10

15

6.8

No

197

90

204

93.2

Water pressure fall

Yes

123

56.4

126

57.3

No

95

43.6

94

42.7

Traveling during two weeks

Yes

78

35.5

73

33.2


No

142

64.5

147

66.8

Pre­dominance rates Obtained by logistic re­gression multi and single-models present in Ta­ble 2 and 3.

Table 2: Distribution of case and control by parent's education


Case

Control


n

%

n

%

Elementary School

Father

67

30.6

53

24.3

Mother

73

33.2

79

35.9

Guidance School

Father

58

26.5

55

25.2

Mother

40

18.2

46

20.9

High School

Father

62

28.3

81

37.2

Mother

78

15.5

75

34.2

University

Father

32

14.6

29

13.3


Mother

29

13.2

20

9.1

Table 3: Association of acute diarrhea with risk factors by univariate logistic regression

Variable



OR*

95% CI

P

Used milk up to 6 month age

Milk

1


<0.001

Powder Milk

3.21

5.72-1.80


Antibiotic usage during the last 15 days

Yes

1


0.040

No

1.53

2.29-1.01


Mother's employment

Yes

1


0.032

No

2.13

4.27-1.06


Mother's  acquaintance with ORS

Yes

1


<0.001

No

3.07

4.55-2.08


Occupancy

Landlord

1


0.002

Tenant

1.80

2.63-1.23


Water slack during the week

Yes

1


0.024

* Adjusted odds ratio;              † 95% Confidence Interval

Table 4: Association of acute diarrhea with risk factors by multivariate logistic regression

Variable


OR*

95% CI

P

Used milk up to 6 month age

Milk

1


<0.001

Powder Milk

3.21

5.79-1.77


Mother's employment

No

1


0.013

Yes

2.48

5.06-1.2


Occupancy

Landlord

1


0.002


Tenant

1.83

2.71-1.24


Adjusted odds ratio ;      † 95% Confidence Interval

Discussion

The recent survey is a case-control study con­ducted to investigate factors which is effec­tive in acute diarrhea of children <5 yr of age. Control group selection in case-control study always has been a sensitive and determinative part of this study and al­though control group is selected from pre­sented patient which their risk factor had the least relation with acute diarrhea disease but concerning the limitation of patients selec­tion, again, there is some selection inaccu­racy. All comparisons must be carried out with great care because of this inaccuracy and for previous studies that did not investi­gate some of these variations.

According to findings of recent study no rela­tion has been observed between sex and children's age in diarrheal episode, indeed af­ter restrict analysis separately in two sexes it was defined that the chance of diarrhea in­fection in boys is decreased by increasing in age, which demonstrate the correlation of age and sex effects. The relation between sex - age and acute diarrhea reports in vari­ous studies, some shows female sex is more li­able to the risk of diarrhea episode and some other contradicts to this. In many stud­ies increasing in age mentioned as conserva­tional factor (10) and some studies contra­dicted this. Age, compared to sex in general, has more significant effect on acute diarrheal episode (11-16).

Mother's milk ingestion until six months of age is one of the findings of recent study, which is verified by various studies. This find­ing can be reiterative on presence of imino-globin and anti-chores in mother's milk that inactively can prevent this disease (17-22).

Inappropriate environmental condition (23) and weak economical status are the impor­tant risk factors of acute diarrhea. Although this study did not measure economical and en­vironmental status directly but concerning that residence status can be indirect assess­ment of economical status, being possessor or lodger is investigated and determined that the chance of diarrhea infection in the in­di­vidu­als with lodging circumstances are more which is reiterative to previous find­ings, if residence status can be acceptable as one of the economical status factors. It is men­tionable that investigations of economi­cal status as an independent factor needs more accurate and wider study (3, 12, 24-28-26).

According to findings of this study, type of in­jective water had no relation with diarrhea disease, which contradicts to previous stud­ies. Various studies, which were conducted in this field, all emphasis on impact of unsani­tary and plumbing water on diarrhea and use of sanitary and packing water, can pre­vent this disease (13, 16, 29).

A disputable fact of this study is the relation of disease with mother's employment. Mother's employment rate of case group is nearly two with comparison to control group. Making reasonable decision concern­ing number of studies conducted in this field is slightly difficult. Indeed, after more pre­cise investigation it was determined that this is because of operative mother's children who are going to day nursery, diarrhea in this cohort can happen because of the day nurs­ery circumstances, and day nursery is a de­facing factor.

Since Mothers were not informed from ill­ness symptoms and did not know how to use ORS at home, then a better and more teach­ing of the family members is necessary in knowing acute diarrhea symptoms, how to use ORS, prescribed drugs and foods during di­arrhea and preventing ways and referring system at times necessary by health cen­ters (30).

Although this study purveys valuable informa­tion and outcomes to identify effec­tive risk factor of acute diarrhea but there was a limitation concerning the hospital was the case and control source. Thus in order to generalize the outcomes to whole society, wider study in the same field as population must be designed. Consider the importance of acute diarrhea's impact on children health with less than five years of age also more over studies in different part of country is rec­ommended.

In conclusion, the necessity of educational and interventionist programs were deter­mined to develop mothers knowledge about ef­fective factors of acute diarrhea.

Acknowledgements

This paper is as a result of a research pro­posal No: 85151 supported by Vice-Chancellor of Mashhad University of Medi­cal Sciences. The authors appreciate and ac­knowledge col­leagues that help us with gath­ering of in­formation.

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