Comparison of the Prevalence and Trend of Malnutrition between 0-6 Years and 7-11 Years Old Iranian Children: A Systematic Review and Meta-Analysis.

BACKGROUND: To plan for decreasing the prevalence of malnutrition among children, reliable data of current status are required. The aim of the present cross-sectional study was to estimate the prevalence and trend of malnutrition among Iranian children.
METHODS: PubMed, ISI Web of Science, Scopus, Google Scholar, and Iranian databases including SID and Magiran were searched for studies published prior to October 2017 with MeSH terms of Malnutrition, Nutrition Disorders, Wasting, Stunting, Underweight, Undernutrition, Nutrition, Anthropometry, Weight, and Children and Iran. Three random effect models were applied to estimate the pooled prevalence of underweight, stunting, and wasting. Meta-regression and cumulative meta-analysis were performed. All analyses were also conducted separately for two different age groups including 0-6 years old (preschool) and 7-11 years old (primary school). Seventy-five studies (information of 1,069,815 individuals) were included in the final meta-analysis.
RESULTS: The overall prevalence of underweight, stunting, and wasting was estimated to be 8.4% [95% confidence interval (CI): 7.6-9.1], 14.5% (95% CI: 13.1-15.9) and 5.6% (95% CI: 5-6.2) in children age 0-6 years, and 6.6% (95% CI: 4.8-8.4), 7.3% (95% CI: 5.6-9.1), and 8.3% (95% CI: 6-10.7) in children age 7-11 years, respectively.
CONCLUSIONS: The cumulative meta-analysis showed a decrease in the general trend of malnutrition in both preschool and primary school children of Iran. Stunting and wasting were the most common form of malnutrition in Iranian preschool and primary school children, respectively. The decreasing trend of malnutrition was much more noticeable about stunting. Copyright:

Introduction

Lack of the provision of children's nutritional needs inhibits optimal growth and development. As a result, malnutrition occurs which is a big challenge that nations face. Although the estimated global prevalence of malnutrition has shown a decline from the 1990s, it still affects a lot of people in low- and middle-income countries. According to the United Nations International Children's Emergency Fund (UNICEF)/World Health Organization (WHO)/World Bank Group Joint Child Malnutrition Estimates in 2017, the worldwide prevalence of childhood stunting and wasting was 22.2% and 7.5%, respectively.[1] It has been estimated that 45% of deaths of children under 5 years of age are related to malnutrition.[2] Malnutrition also has long-term consequences such as poor physical and mental function, increased vulnerability to infections, developing noncommunicable diseases in adulthood, and economic burden for healthcare system.[3] Some of these effects can be persistent and irreversible.[4] Despite classification of Iran as an upper-middle income country by the World Bank and an increase in the number of overweight and obese children, malnutrition is still a problem in this country. In the UNICEF global nutrition report in 2016, Iran has been ranked 14th and 53rd regarding stunting and wasting among nearly 130 countries, respectively.[5] A national survey of the under-5-year Iranian children in 2010 showed that 5.7% were underweight, 10.13% were stunted, and the prevalence of wasting was 3.29%.[6]

Different factors may play roles in developing pediatrics malnutrition. Socioeconomic status, infectious diseases, maternal educational level, poor hygiene, and low health literacy are the most important factors determining undernutrition in children.[7] Lack of access to health services, low education,[8910] poverty, food insecurity, and lack of nutritional knowledge have been proposed as main risk factors of malnutrition in Iran.

To plan for decreasing the prevalence of malnutrition among children, reliable data sources are required. The huge amount of all national information in this field should be summarized with a systematic review study. In addition, evaluating national trend of malnutrition can help policymakers to assess the effectiveness of interventional programs designed to solve the problem. Therefore, we conducted a systematic review and meta-analysis to determine the prevalence and trend of malnutrition in 0–6 years compared with 7–11 years old Iranian children. To the best of our knowledge, our study is comprehensive because (1) it covers two age groups of children, (2) it is based on all three indices of malnutrition (underweight, stunting, and wasting), and (3) it investigates the trend of malnutrition. According to our knowledge, there is no comprehensive study evaluating the trend of malnutrition among Iranian children.

Methods

Study design and search strategy

PubMed, ISI Web of Science, Scopus, Google Scholar, and English and Persian Iranian databases including SID and Magiran were searched for studies published prior to October 2017 with MeSH terms “malnutrition OR wasting OR wasted OR stunting OR stunted OR underweight OR undernutrition OR undernourished OR nutrition OR anthropometry OR weight OR height OR stature OR failure to thrive OR nutrition status” AND “children OR child OR childhood” AND “Iran.”

Based on the definition of the WHO, malnutrition in children is diagnosed when weight for age, height for age (HAZ), or weight for height (WHZ) z-scores are below 2 standard deviation compared with the international reference median value.[11]

Inclusion and exclusion criteria

In addition to primary articles, articles' references were also manually searched for additional studies. After excluding duplicates, the titles and abstracts of each article were reviewed independently by two of the authors for inclusion. The inclusion criteria were as follows: studies that were conducted in Iran (published articles in either Persian or English languages), participants less than 12 years, and classification of malnutrition according to the National Center for Health Statistics (NCHS)/WHO criteria.

The exclusion criteria were reported malnutrition using percentiles or percent of median (not based on the WHO definition of malnutrition), studies on nonhealthy children, and studies which their full-texts were not found after contacting their journal office. In cases of disagreement between two authors, the third author was consulted.

Quality assessment and data extraction

The quality of studies was assessed through “Quality Assessment Checklist for Prevalence Studies” (adapted from Hoy et al.).[12] The total score of this checklist was categorized into three subgroups including low risk (0–3), moderate risk (4–6), and high risk (7–9) of bias. Studies with a low risk of bias were included in meta-analysis accordingly.

Data analysis

The variance of underweight, stunting, and wasting, as the three most commonly used anthropometric indices for the assessment of malnutrition in children, was computed using the binomial distribution formula in each study. Publication bias was evaluated through visual examination of funnel plots and through Egger's test. The heterogeneity index among different studies calculated using tau square (t2) test.

As the heterogeneity among studies was significant, three random effect models using Meta command in Stata was applied to estimate the pooled prevalence of underweight, stunting, and wasting. The effect of different variables as the source of the heterogeneity was investigated using meta-regression approach (quality score, mean age, age group, deprivation index, date of publication group, and sample size group were the variables that were included in the meta-regression approach). Cumulative meta-analysis was performed to evaluate the time-trend of each anthropometric index of children malnutrition after data sorting by publication date. The quality score of studies, mean age of participants, age group, sample size of studies, publication date, and deprivation index of cities were entered in meta-regression as independent variables. The sample size was categorized into extra small (n< 200), small (n = 201–500), medium (n = 501–1000), large (n = 1001–10,000), and extra-large (n ≥ 10,000). Publication date of studies was categorized into four groups: before 2000, 2000–2005, 2006–2011, and 2012–2017. Deprivation index of cities was determined according to Sheikh-Beiglou's study[13] in which cities have a score of 1–30 based on four methods used to measure the development level. All analyses were also conducted separately for two different age groups of target population including 0–6 years old (preschool) and 7–11 years old (primary school) and were compared. We used Stata version 11 (College Station, TX, USA) for conducting the analysis.

Results

Summary of included studies

Out of 513 identified studies through our search strategy, 75 studies (age group 0–6, 60; and age group 7–12, 15 studies) had our inclusion criteria and were included in the meta-analysis [Figure 1 and Table 1]. In total, the information of 1,052,143 children age 0–6 years and 17,672 children age 7–11 years were considered in meta-analysis.

Figure 1

Study selection process based on PRISMA 2009 flow diagram

Table 1

Description of studies that met our eligibility criteria

Authors	Year of publication	Province/city	Sample Size	Prevalence (%)			Age	Quality score
				WAZ	HAZ	WHZ
0-6 years old
Farrokh-Eslamlou et al.[23]	2013	West Azarbaijan Province	3341	4.3	8.7	7.5	Under 5 years	1
Holakoui-Naieni et al.[24]	2002	Eslamshahr_Rey_Qom	1624	5.4	24.4	4.5	Under 5 years	2
Yarparvar et al.[25]	2006	Bam	500	15.2	8.9	5.6	6-59 months	1
Farajzadeh et al.[26]	2012	Birjand	1132	9.9	3.6	25	5-7 years	1
Fesharakinia et al.[27]	2013	Birjand	480	6.3	9.8	0.8	Under 5 years	1
Poorabdollahi et al.[28]	2004	Tabriz	400	6.6	9.4	2.0	Under 6 years	2
Nasiri-Rineh et al.[29]	2003	Tonekabon	425	37.0	80.0		Under 5 years	1
Naderi-Beni et al.[30]	2013	Chadegan	403	6.5	12.7	2.7	Under 5 years	1
Ramazani et al.[31]	2009	South Khorasan Province	700	10.6	5.3	11.6	0-24 months	1
Sharifzadeh et al.[32]	2008	South Khorasan Province	1807	12.9	16.6	7.5	Under 6 years	1
Moradi-Lake et al.[33]	2009	Robat-Karim	1406		7.7		Under 6 years	1
Salem et al.[34]	2002	Rafsanjan	1070	11.5	10.3	5.8	1-5 years	1
Ansari et al.[35]	2009	Zahedan	1245	3.4	7.6	4.2	2-5 years	2
Sheykhi et al.[36]	2012	Zahedan	514	17.3	25.3	6.8	6-59 months	2
Nakhshab et al.[37]	2002	Sari	700	3.9			Under 2 years	1
Rimaz[38]	2004	Savojbolagh	1243	4.1	9.4	3.9	Under 5 years	1
Emamian et al.[39]	2011	Shahrood	1395	5.7	10.3	4.7	Under 6 years	1
Zabihi et al.[39]	2013	Babol	782	2.8	2.7	6.9	Under 2 years	2
Nojomi et al.[40]	2003	Karaj	600	13.9	20.3	4.9	Under 5 years	1
Ahmadipour et al.[41]	2016	Kerman	360	9.2	6.4	15.2	2-5 years	2
Razavieh et al.[42]	2001	Kermanshah	400	17.5	8.8	14.3	0-36 months	3
Veghari et al.[43]	1999	Gorgan	491	4.7	40.3		Under 5 years	2
Kabir et al.[44]	2006	Golestan Province	1473	4.1	10.8	3.2	Under 2 years	2
Soheili-Azad et al.[45]	2004	Nahavand	300	3.0	13.3	2.7	0-36 months	2
Gholami et al.[46]	2013	Neishabour	1621	8.1			3-6 years	2
Dehghan et al.[47]	2004	Dayer	450	14.4	15.4	9.1	Under 5 years	2
Hooshyarrad et al.[48]	2008	National	2562	7.6	13.1	4.5	Under 5 years	0
Sheikholeslam et al.[49]	2008	National	34200	5.2	4.7	3.7	Under 5 years	0
Veghari et al.[50]	2007	Gorgan	2802	6.4	48.3		Under 6 years	2
Veghari et al.[51]	1997	Gorgan	2639	6.7	45.5	4.3	Under 5 years	2
Veghari et al.[51]	2004	Gorgan	2858	5.0	19.3	3.4	Under 5 years	2
Nouri-Saeidlou et al.[52]	2014	West Azerbaijan	902	2.3	7.3	1.4	6-59 months	1
Nouri-Saeidlou et al.[52]	2014	Kermanshah	829	3.6	3.3	2.6	6-59 months	1
Nouri-Saeidlou et al.[52]	2014	Isfahan	794	5.9	11.2	5.0	6-59 months	1
Malekafzali et al.[53]	2000	Sibak_Borujen	99	11.0		9.0	Under 5 years	3
Namakin et al.[54]	2014	Birjand	822	5.2	11.8	1.8	Under 2 years	1
Veghari et al.[55]	2015	Gorgan	2530	6.4	15.4	2.6	Under 5 years	2
Shafieian et al.[56]	2013	Mashhad	671	4.3	3.1	4.3	24-59 months	1
Motlagh et al.[57]	2010	National	862433	19.1	6.5		6-7 y	0
Delvarianzadeh et al.[58]	2017	Shahroud	706	7.1	5.9	4.5	Under 2 years	1
Zahraei et al.[59]	2016	Sistan-va-Baluchestan	263		11.4		12 months	1
Maddah et al.[60]	2007	Rasht	1319	7.1	8.6	8.0	3-6 years	1
Veghari et al.[61]	2009	Gorgan	1569	5.2	21.7		25-60 months	2
Almasian Kia et al.[6]	2017	National	8443	5.7	10.1	3.3	Under 2 years	0
Jahanihashemi et al.[62]	2017	Qazvin	1351	4.8	5.8	10.3	0-72 months	1
Akhlaghi et al.[63]	2013	Yasuj	285	2.8	1.4	5.0	≤18 months	2
NouriSaeidlou et al.[64]	2014	Salmas (west Azerbijan)	902	9.0	28.7	5.8	0-59 months	1
Sheikholeslam et al.[65]	2004	Ilam	1178	10.6	19.6	1.1	6-35 months	1
Sheikholeslam et al.[65]	2004	Borazjan (Bushehr)	1117	17.7	27.8	6.8	6-35 months	1
Sheikholeslam et al.[65]	2004	Bardsir (Kerman)	1031	25.9	34.0	3.9	6-35 months	1
Ahmadi et al.[66]	2014	Shiraz	150	1.4	4.8	2.7	36-48 months	1
Zavoshy et al.[67]	2012	Qazvin	2385			4.1	3-6 years	1
Kavosi et al.[68]	2014	Fars Province	15408	9.7	9.5	8.2	0-6 years	1
Payandeh et al.[69]	2013	Khorasan	70339	7.5	12.5	4.4	0-5 years	1
Karajibani et al.[70]	2014	Sistan and Baluchestan	1570	19.4	32.1	9.4	0-6 years	1
Sharifzadeh et al.[71]	2010	South Khorasan Province	1807	12.8	16.6	7.4	Under 6 years	1
Mahyar et al.[72]	2010	Qazvin	804	1.3	2.8		0-24 months	1
Khatibi et al.[73]	2016	Kerman	443	25.2	3.1		2-6 years	1
Haratipour et al.[74]	2016	Shahroud	1850	6.7	5.8	7.7	4-6 years	1
Edalat et al.[75]	2014	Shiraz	202	12.3	4.9	12.3	3-6 years	1
7-11 years old
Hooshmand et al.[76]	2012	Ahwaz	2232	1.4	5.6	1.7	6-9 years	1
Aghamolaei et al.[77]	2003	Bandar Abbas	1300	12.2	11.7	15.7	7-12 years	1
Mahboob et al.[78]	2004	Tabriz	480		4.4	4.6	6-12 years	2
Pourhashemi et al.[79]	2007	Tehran	788	1.5	1.8	5.2	7 years	1
Delvarianzadeh et al.[80]	2005	Shahrood	630	6.5	8.1	5.9	6-12 years	2
Delvarianzadeh et al.[81]	2006	Shahrood	890	14.7	15.3	11.6	6-12 years	2
Darvishi et al.[82]	2009	Kordestan Province	1100	6.9	5.6	10.8	7-11 years	1
Alavi-Naeini et al.[83]	2002	Kerman	905	8.8	11.8		10 years	1
Noroozi et al.[84]	2011	Golpayegan	1062	5.4	3.0		7-11 years	2
Dehghan et al.[85]	2010	Larestan	876	7.3	6.5	9.8	7-11 years	1
Alipour et al.[86]	2016	Tabriz	330	1.2		3.6	7-11 years	1
Nematian et al.[87]	2008	Tehran	209		2.8	21.0	7-11 years	1
Hamedi-Shahraki et al.[88]	2016	Sistan and Baluchestan	610	12.8	16.9		7-11 years	1
Veghari et al.[9]	2013	Gorgan	5698	3.2	4.9	5.1	6-10 years	2
Soheili Azad et al.[45]	2004	Tehran	562	6.5	6.5	9.6	6-10 years	1

WAZ=Weight for age, HAZ=Height for age, WHZ=Weight for height

Meta-analysis

The overall prevalence of underweight was 8.1% [95% confidence interval (CI): 7.3–8.8], stunting was 13.1% (95% CI: 11.9–14.2), and wasting was 6.1% (95% CI: 5.5–6.6) in both age groups.

The corresponding figure in two subgroups of age is shown in Table 2, Figures 2a-f and 3. The results of meta-regression showed the date of publication (coefficient = −0.02; 95% CI: −0.04; −0.004) and deprivation index (coefficient = 0.002; 95% CI: 0.11–0.35) for underweight; the date of publication (coefficient = −0.06; 95% CI: −0.09, −0.03) for stunting; and the mean age of children in each age group (coefficient = 0.02; 95% CI: 0.009–0.03) and age group (coefficient = −0.09; 95% CI: −0.16, −0.02) for wasting were the main sources of the heterogeneity [Table 3].

Table 2

Prevalence of underweight, stunting, and wasting in 0-6 and 7-11 years old Iranian children

	0-6 years	7-11 years
Underweight % (95% CI)	8.4 (7.6-9.1)	6.6 (4.8-8.4)
Stunting % (95% CI)	14.5 (13.1-15.9)	7.3 (5.6-9.1)
Wasting %(95% CI)	5.6 ( 5-6.2)	8.3 (6-10.7)

CI=confidence interval

Figure 2a

Forest plot of the prevalence of underweight in 0–6 years old Iranian children

Figure 2f

Forest plot of the prevalence of wasting in 7–11 years old Iranian children

Figure 3

The prevalence of malnutrition in 0–6 years old Iranian children compared with 7–11 years old children. WAZ = Weight for age, HAZ = Height for age, WHZ = Weight for height

Table 3

Results of meta-regression model for underweight, stunting, and wasting in Iranian children (for studies published prior to October 2017)

Predictors	WAZ		HAZ		WHZ
	Coefficient (95% CI)	P	Coefficient (95% CI)	P	Coefficient (95% CI)	P
Quality score	−0.01 (−0.04-0.1)	0.25	0.01 (−0.04-0.06)	0.66	0.007 (−0.01-0.03)	0.49
Mean age	0.01 (−0.004-0.02)	0.15	−0.004 (−0.03-0.02)	0.74	0.02 (0.009-0.03)	0.00*
Age group (reference group: 0-6 years)	−0.08 (−0.17-0.01)	0.08	−0.06 (−0.24-0.11)	0.46	−0.09 (−0.16- -0.02)	0.01*
Sample size group	−0.01 (−0.026-0.006)	0.22	0.005 (−0.03-0.04)	0.74	−0.0009 (−0.01-0.01)	0.88
Date of publication group	−0.02 (−0.04- -0.004)	0.02*	−0.06 (−0.09- -0.03)	<0.001*	−0.001 (−0.01-0.01)	0.83
Deprivation index	0.002 (0.11-0.35)	0.02*	0.0008 (−0.002-0.004)	0.57	0.0006 (−0.0005-0.002)	0.27

WAZ=Weight for age, HAZ=Height for age, WHZ=Weight for height; CI=Confidence interval. *Significant coefficient

Forest plot of the prevalence of underweight in 7–11 years old Iranian children

Forest plot of the prevalence of stunting in 0–6 years old Iranian children

Forest plot of the prevalence of stunting in 7–11 years old Iranian children

Forest plot of the prevalence of wasting in 0–6 years old Iranian children

Cumulative meta-analysis

The results of meta-regression and cumulative meta-analysis showed the significant decreasing trends of underweight and stunting in both age groups; however, the trend of wasting was decreasing but not significant. This trend was more obvious in age group 0–6 years old. Moreover, the trend of reduction was more noticeable for stunting in both age groups [Table 3 and Figure 4a-f].

Figure 4a

Cumulative meta-analyses of the prevalence of underweight in 0–6 years old Iranian children

Figure 4f

Cumulative meta-analyses of the prevalence of wasting in 7–11 years old Iranian children

Cumulative meta-analyses of the prevalence of underweight in 7–11 years old Iranian children

Cumulative meta-analyses of the prevalence of stunting in 0–6 years old Iranian children

Cumulative meta-analyses of the prevalence of stunting in 7–11 years old Iranian children

Cumulative meta-analyses of the prevalence of wasting in 0–6 years old Iranian children

Discussion

This systematic review and meta-analysis was conducted on the published literature to estimate the prevalence of malnutrition among Iranian children. Totally, 75 published studies gained eligibility for inclusion in this review, most of which were published during the past decade. The national prevalence of underweight, stunting, and wasting in children age 0–6 years was as follows: 8.4%, 14.5%, and 5.6%. The corresponding figures for children age 7–11 years was 6.6%, 7.3%, and 8.3%. According to the reported statistics of malnutrition in neighboring countries of Iran including Turkey in 2008:[14] (underweight 2.8%, stunting 10.3%, and wasting 0.9%) and Pakistan in 2012:[15] (underweight 39.4%, stunting 63.9%, and wasting 17.9%), Iran represents an intermediate state. This variation could be related to the differences in risk factors of pediatrics malnutrition including short birth spacing, socioeconomic status, mother's low level of education, and insufficient nutritional knowledge.[16]

Interestingly, stunting was more prevalent among 0–6 years old children. This observed prevalence was higher than the World Bank data (7.1% in 2004)[17] and lower than the global prevalence of stunting among children under 5 years of age (25% in 2013).[18] In addition, compared with the latest WHO website statistics,[1] our finding is more promising. Our findings confirm that stunting is the most common form of malnutrition in children below 6 years of age.[18] Stunting is associated with higher morbidity and mortality rates, retardate physical and mental growth, and an increased risk of adulthood diseases.[18] As stunting is reflective of chronic malnutrition, performing more accurate screening programs might result in achieving global nutrition targets for 2025.[19]

In children age 7–11 years, wasting was more noticeable than underweight and stunting. In contrast to HAZ, WHZ is a measure of more acute malnutrition. This finding was comparable with a study in Nigeria by Adedeji et al. In this study, the prevalence of thinness was 11.1%, underweight had a prevalence of 10.7%, and 10.1% of children were stunted.[20] Inadequate intake of carbohydrate, having a large family size, and household food insecurity have been introduced as determinants of malnutrition in school children.[21]

The results of cumulative meta-analysis can be interpreted in two ways: first, regarding the last line of cumulative meta-analysis result, the cumulative prevalence of underweight, stunting, and wasting was 6.5% (95% CI: 6.4–6.6), 6.9% (95% CI: 6.8–6.9), and 4.3% (95% CI: 4.2–4.4) in children age 0–6 years, and 3.4% (95% CI: 3.1–3.6), 5.3% (95% CI: 5–5.7), and 4.7% (95% CI: 4.4–5) in children age 7—11 years, respectively. Second, the general trend of malnutrition is decreasing in both preschool and primary school Iranian children; this is much more noticeable about stunting. Our results are comparable with the world trend in malnutrition. A decrease in the global prevalence of malnutrition has been reported from nearly 40% in 1990 to 25% in 2013.[18] This illustrates Iran's significant success in achieving global nutrition targets for 2025. This reduction was highly significant for Asian countries. According to the “ first 1000 days theory,”[22] failure to grow in the period between conception and child's second birthday has a critical role in being stunted. So, our further reduction in stunting compared with wasting and underweight could be attributed to improved prenatal health cares.

Limitation of Study

This study can be considered as an important step in highlighting the extent of the problem by producing reliable data sources and help policymakers improve children nutrition policies. However, several limitations should be considered when interpreting our findings. Mentioned heterogeneity could confound the observed results. In addition, some studies included in the review did not report all malnutrition indicators, or few studies had presented their results divided by sex; therefore, we were unable to perform subgroup analysis by sex. Moreover, any potential misclassification bias is possible to have been occurred in the results of included studies.

Conclusions

To the best of our knowledge, this systematic review is the first study that compared the pooled prevalence and trend of malnutrition between Iranian preschool and primary school children. Stunting and wasting were the most common form of malnutrition in Iranian preschool and primary school children, respectively. The general trend of malnutrition is decreasing in both preschool and primary school Iranian children; this is much more noticeable about stunting. In summary, the prevalence of malnutrition in Iran was in the lower limit of the global statistics. Higher number of stunted children under 5 years of age is an alarm for politicians to design preventive national programs for controlling chronic malnutrition.

Financial support and sponsorship

This research was supported by Arak University of Medical Sciences.

Conflict of interest

There is no conflict of interest.