Prevalence of Childhood Obesity in Developing Countries

The prevalence of childhood obesity is increasing worldwide. In fact, some argue that rates of childhood obesity are increasing most dramatically in developing countries. The term developing country is defined by the World Bank as low- and middle-income economies, technically those with a Gross National Product (GNP) per capita of less than $3,465. Chronic undernutrition and infectious disease have long been associated with developing countries; however, in recent years many developing countries have shown a concurrent increase in both obesity and undernutrition often referred to as the “dual burden” of malnutrition.

Globalization, economic development, and other factors such as commercialization of agriculture and urbanization have led to changing patterns of living, which can be viewed as part of the nutrition transition. Nutrition transition is generally defined as the shift away from diets high in fiber and complex carbohydrates toward more energy-dense diets that are high in sugars, refined foods, and saturated animal fats, coupled with increasingly sedentary lifestyles. These dietary and lifestyle shifts have been attributed to changes such as the low cost of highly refined oils and carbohydrates, the move toward motorized transportation, the increase in sedentary occupations as well as ownership of a television.

While children are exposed to these influences, it seems the impact of the nutrition transition increases with age, meaning that older individuals are more likely to become obese. In addition, the pattern of obesity within developing economies varies greatly according to class, gender, age, and region (urban–rural). For example, while certain countries, such as Brazil, Mexico, and Chile, show an inverted relationship between social class and obesity, this pattern is not yet observed in India. Regardless of the distribution of obesity within country, in developing countries it has been recognized that rates of obesity are increasing rapidly in children.

It must be acknowledged that these prevalence statistics should be read with awareness of their limitation. Given the importance of monitoring overweight and obesity prevalence, it is remarkable that there is a general lack of precise data by country. Part of the explanation for this is that obesity rates are increasing so fast that prevalence statistics become quickly outdated. In addition, it is difficult to make comparisons between studies because of a lack of consensus on the most appropriate way to define obesity in childhood. For example, before 2000, there was no internationally accepted definition of childhood obesity. In adult populations, a body mass index (BMI) cutoff has been selected to reflect functional impairment and health risk; however, many of the detrimental health effects of childhood obesity appear in adult life, not necessarily in childhood. Prior to 2000, some studies [Page 625]defined obesity in children as weight-for-height Z-scores over two standard deviations above the World Health Organization (WHO)/National Center for Health Statistics (NCHS), while others used this cutoff to define overweight.

In 2000, the International Obesity Task Force devised a set of guidelines for defining overweight and obesity in childhood based on nationally representative cross-sectional surveys on growth from six countries (Brazil, Great Britain, Hong Kong, the Netherlands, Singapore, and the United States). These standards provide cutoff points for BMI in childhood using data set-specific centiles linked to adult cutoff points of a BMI of 30 at age 18 years. However, given that functional impairments occur at different BMIs for different populations, some epidemiologists have argued that a flexible BMI standard should be used.

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