Recent studies indicated that the Iranian population is experiencing rapid changes in diet and physical activity(Reference Ghassemi, Harrison and Mohammad1). Available data have shown that one-fifth of Iranian children and adolescents are overweight or obese(Reference Mohammadpour-Ahranjani, Rashidi and Karandish2, Reference Maddah3), and metabolic syndrome is highly prevalent among them(Reference Esmailzadeh, Mirmiran and Azadbakht4). While most of these data were taken from the developed parts of the country in urban areas, there is little information on children from the less privileged parts of Iran.
Zahedan is the centre of Sistan and Bluchestan province in south-east Iran. In the last two decades, nutritional surveys focused on children under 5 years of age and high prevalences of stunting and underweight among children were reported in this region(5). Meanwhile, a secular trend in decreasing thinness and increasing the prevalence of overweight among adults has been reported in southern Iran(Reference Janghorbani and Parvin6, Reference Shahraki, Shahraki and Ansari7). However, few data are available on overweight and underweight in school age children in southern Iran. We therefore aimed to study the prevalence of overweight and underweight in a group of primary-school children with special focus on their maternal education in Zahedan, south-east Iran.
Methods and subjects
The present study was designed to evaluate the prevalence of overweight/obesity and underweight among the elementary-school children (7–11 years) in urban areas in Zahedan, southern Iran. A random sample of 1184 students was selected between October 2008 and March 2009 from all elementary schools in Zahedan. Selection of the subjects was initially made at school level, not by age of the students. As the age of 105 students was not in the range of the protocol, they were excluded and 1079 observations (boys = 500 and girls = 579) were included in the data analysis.
Information on child’s age and parental educational levels were gathered using a questionnaire filled in by the parents. Anthropometric measurements were performed in lightly dressed children without shoes in the morning. Body weight was measured to the nearest 0·1 kg using a balanced-beam scale, height was measured to the nearest 0·5 cm with the children standing up, and with head, back and buttock on the vertical land of the height gauge. Age- and sex-specific BMI cut-offs proposed by the WHO were used to define underweight and overweight/obesity. Underweight and overweight/obesity were defined as age-adjusted BMI less than 3rd and above 85th percentile of the WHO chart, respectively(8).
All the parents gave written consent for participation in the present study. The study protocol was approved by the ethical committee of the Research Center for Children and Adolescent Health at Zahedan University of Medical Sciences and Health Services.
Statistical analysis
The χ 2 test was used for detecting differences in the prevalence of overweight/obesity as well as underweight between groups. In data analysis, mothers’ educational level was classified as either ≤ 7 years of schooling or > 7 years of schooling.
Values are given as means. P values < 0·05 were considered as the level of significance. Analyses were performed using the Statistical Package for Social Sciences statistical software package version 10·01 for Windows (SPSS Inc., Chicago, IL, USA).
Results and discussion
These results showed that 8·9 % of the boys and 10·3 % of the girls were overweight or obese (P < 0·05), and 22·8 % of the boys and 19·9 % of the girls were underweight (P < 0·001).
Prevalence of overweight/obesity and underweight by age is shown in Table 1. Overweight was more prevalent at higher age groups than lower ones and it was more prevalent among the girls than the boys. Underweight was more prevalent than overweight in boys and girls except in 11-year-old girls. Table 2 shows that the prevalence of overweight was directly related to maternal education in boys and girls.
Frequency of overweight and underweight in boys and girls in Zahedan, Iran
Prevalence of overweight and underweight by maternal educational levels in boys and girls in Zahedan, Iran
*P < 0·001; **P < 0·05.
Provinces in southern Iran, including Kerman, Sistan and Bluchestan, were known to have high prevalence of underweight and stunting among children and adults(5, Reference Janghorbani and Parvin6). However, secular changes in increasing overweight/obesity, especially in women, have been documented in these areas(Reference Janghorbani, Amini and Willet9). The present study suggests that while underweight is still the main nutritional problem among young children, it might be replaced by overweight as children grow to adolescence. This is of concern because early chronic undernutrition and poor growth with subsequent rapid increase in fat mass near to adolescence may predispose this population to risk of chronic diseases in adulthood(Reference Painter, de Rooij and Bossuyt10). Studies undertaken in the adult population in Zahedan have shown that overweight, and especially central obesity, is not uncommon in this economically least privileged part of Iran(Reference Shahraki, Shahraki and Ansari7).
The present study showed that girls were more at risk of overweight than boys. This finding is concordant with the results of similar studies in other parts of Iran that showed women at any age are more prone to obesity than men(Reference Mohammadpour-Ahranjani, Rashidi and Karandish2, Reference Hamidi, Fakhrzadeh and Moaweri11). This sex difference in the prevalence of obesity in Iran and other Islamic Arabic countries in the region calls for further studies to investigate the possible association of Islamic dressing style or other cultural beliefs with obesity prevalence. In addition, the present study showed that overweight among children is directly associated with maternal educational level. Shahraki et al.(Reference Shahraki, Shahraki and Ansari7) reported that BMI was inversely related to educational level in Iranian women in Zahedan. Furthermore, in spite of a high prevalence of obesity in adult women of low educational level in northern Iran, overweight in children was directly related to maternal education(Reference Maddah and Nikooyeh12). In developing countries, and especially in lower socio-economic groups, heaviness may be believed as an indicator of good health for children(Reference Jain, Sherman and Chamberlin13). We did not collect data on economic status of this population and further studies are needed to clarify the relation between socio-economic status and obesity in children in Iran.
In conclusion, the present study indicated that: (i) underweight is possibly the most important nutritional problem among pre-school children in Zahedan; and (ii) weight problem of the study population varies by their age group. While most of the young children were underweight, overweight was prevalent among those near to adolescence, especially in girls. This rapid increase in fat mass near adolescence is of concern because obesity at this age is more likely to be related to adulthood obesity and metabolic diseases. More detailed studies are needed to clarify whether the current overweight adolescents are the past underweight children.
Acknowledgements
This work was supported by the Sistan–Bluchestan Unversity of Medical Sciences, and also by the Research Committee of Zahedan University of Medical Sciences. The authors declare that there are no conflicts of interest. The authors thank the students and their parents for their participation, as well as the school personnel for their cooperation in the present study. M.M. designed the study and wrote the paper. T.S. helped in the data analysis and collected the data. M.S. helped in collecting data and writing the paper.
