Introduction Obesity has emerged as a pervasive public health problem among the

world's children and adolescents that is increasing at an alarming rate.

In 2008, an estimated 170 million children aged less than 18 years were found to be overweight or obese, and it has been projected that about 30% of all children will be affected by this prominent nutritional and

metabolic disorder by the year 2030.

The disorder represents fat accumulation in adipocytes following an excess calorie intake through consumption of food that exceeds the body's

metabolic requirements for growth, development and physical activities.

An individual is considered obese if he or she becomes excessively

overweight with high level of accumulated fat in the body. Body Mass Index (BMI), defined as weight in kg/(height in meter)2 is by far

the most commonly used measure of obesity. Although BMI calculations are done the same way for children and adults, the

criteria for interpreting the BMI number is different for children and adolescents from the criteria used for adults.

Unlike adults, BMI is interpreted through categories that take into account sex and age in the case of children and adolescents.

This is based on the premise that the amount of body fat differs between boys and girls and changes with age.

Obesity in early life is crucial as it often leads to increased morbidity and mortality during young adulthood and posesincreased risk of being obese in adulthood.

For instance,obesity has been associated with a number of chronic disordersincluding hyperlipidaemia, hypertension, cardiovascular disease, metabolic

syndrome, glucose intolerance and kidney disorders in early childhood. Obesity led type 2 diabetes mellitus has been shown to increase dramatically

among children over the last two decades. Obese children are also at increased risk of suffering from several psychological problems including

depression. The economic implications of childhood obesity and its huge burden on health systems have been reported.

Cut off values of BMI for overweight

Agency Tendency for overweight

State of overweight

WHO > 25 kg/m2 > 30 kg/m2

IOTF > 23 kg/m2 > 25 kg/m2

NCHS > 85thcentile(90th centile recently)

> 95th centile(97th centile recently)

Although global recognition about the health hazards of obesity in childhood and adolescence is relatively recent, ithas been well established as a public health problem in economically developed countries.

While the problem was restricted to the developed countries of the world until recently, the situation has changed drastically in recent years with studies reporting a pronounced increase in obesity prevalence among children and adolescents in developing countries over the past few decades.

A recent well conducted systematic analysis of global, regional,and national

prevalence of overweight and obesity reported an increase in prevalence rates among children and adolescents in developing countries, from 8.1% to 12.9% among boys and from 8.4% to 13.4% among girls during 1980-2013.

Although childhood obesity prevalence is comparatively higher in developed countries, larger numbers of obese children tend to reside in low and middle income regions of the world due to the demographic profiles of their populations.

While countries in the South Asian region e Bangladesh, India, Pakistan, Nepal, Maldives, Bhutan and Sri Lanka e are predominantly economically underprivileged, an increasing trend in the prevalence of childhood obesity has been observed in recent years in countries where data are available.

For example, prevalence of childhood obesity (5-19 yrs)increased from 9.8% to 11.7% between 2006 and 2009 in India,22 and it almost doubled among school children (5-14 yrs) in Pakistan between 1994 and 2005.This increasing trend of obesity prevalence among the South Asian children is beyond expectation as a vast majority of childrenare reported to be undernourished.

The problem of obesity remain largely unrecognized in the region, and it would seem that the individual studies do not provide sufficient evidence on their own to warrant appropriate action.

This review aims to systematically synthesize the published literature on factors associated with overweight and obesity among childrenand adolescents in South Asian countries to inform policy,practice and future research.

Barker’s Hypothesis FOAD 1986

• Fetal origins of adult-onset diseases (FOAD)

• Under nutrition and unfavorable intrauterine environment at critical periods in early life can cause permanent changes (in both structure and function) in developing systems of the fetus (i.e. programming).

• May manifest as disease over a period of time due to `dysadaptation’ with changed environmental circumstances

Barker DJP. Mothers, babies and health in later life. Edinburgh: Churchill Livingstone, 1998.

Maternal malnutrition

FETAL UNDERNUTRITION(Nutrient demand exceeds supply)

HYPERLIPIDAEMIAHYPERTENSION CENTRAL OBESITY INSULIN RESISTANCE

Type 2 Diabetes and CHD

Muscle mass Cortisol Impaired development Fat mass (Liver, Pancreas, Blood vessels)

Placental transfer

Fetal genome

Altered body composition Early maturation Brain sparingDown regulation of growth

Fall CHD. The fetal and early origins of adult disease. Review. Indian Pediatr 2003; 40:480-502

Developmental origins of adult disease: hypothesis

MethodsA systematic review design was employed to identify, appraise and summarize the existing evidence on factors associated with overweight and obesity among children and adolescents for this study. This design was considered to be advantageous as systematic reviews allow the systematic collation and appraisal of existing evidence to generate unbiased, accurate and reliable information. The overall review question was framed using Population, Intervention (exposures), Comparator, Outcome and Study design (PICOS) framework.The population comprised of children and adolescents aged 0-18 years in South Asian countries i.e., India, Bangladesh, Pakistan, Bhutan, Nepal, Maldives, Afghanistan and Sri Lanka. The primary outcome measure was overweight and obesity measured using Body Mass Index (BMI). The study design included quantitative and qualitative primary studies.

Data sourcesA range of electronic data bases were used to locate primary studies published between January 1990 and June 2013 from India, Pakistan, Nepal, Bangladesh, Sri Lanka, Bhutan and The Maldives. Searched databases included: PubMed, PubMed central, EMBASE, MEDLINE, BioMed central, Directory of Open Access Journals (DOAJ) and the electronic libraries of the authors‘ institutions.Additionally a number of other specialist databases were searched, including the Cochrane Database of Systematic Reviews, and other online resources to identify potentially eligible primary reports, reviewarticles, and reports that might contain relevant citations. Bibliographies of full text articleswere also inspected to find any additional relevant studies

Study selectionThe initial search resulted in 1287 titles of which 971 were excluded based on the title and abstract. 316 full text articles were retrieved and screened against a checklist of inclusion criteria including geographical location, population (aged 0-18 years), and the use of Body Mass Index (BMI) as the measurement tool of obesity. The inclusion criteria are presented indetail in Table 1.. Five more studies were found by

searching reference lists and contacting experts in the field. A total of 27 articles met the study selection criteria ofwhich 16were further excluded due to issues relating to quality and the reported measures. 11 studies were included in the final review

The selected studies were critically appraised for their methodologicalquality using a modified Quality Assessment Tool, devised by the Effective Public Health Practice Project (EPHPP).27 Studies were graded against four methodological quality criteria: •sample representativeness; •study design and •appropriateness of the outcomemeasure;• aspects of data collection; data analysis and•interpretation. The search and selection process are illustrated in Fig. 1..

ResultsAll the selected studies were school based and majority (nine) employed a cross-sectional descriptive study design.Of the remaining, one used a case-control design37 and the other used a case-control design following a cross-sectional design. All the selected studies were based on primary research conducted in South Asian region and published in English language between 2000 and 2013 in peer reviewed journals. Majority of the studies were done in India (7), followed by Pakistan (3) and Bangladesh (1) and the population consisted of children and adolescents under the age of 18 years. For classifying overweight and obesity, four studies employed Centres for Disease Control and Prevention's (CDC) age and sex specific growth chart and three studies used World Health Organisation's (WHO) growthchart as reference standard. The other reference standards used included Indian Academy of Paediatrics Growth Monitoring guidelines from birth to 18 years28 and InternationalObesity Task Force (IOTF) criteria. Two studies did not specify the population reference standards that were used.

Prevalence of overweight and obesityPrevalence of overweight and obesity showed wide variations among the included studies. Overall, prevalence of overweight ranged from 3.1% to 19.7% . Obesity ranged between 1.2% to 14.5%. Prevalence rates for overweight were higher than that of obesity in more than half of thestudies. Two studies reported higher prevalence of obesity compared to overweight. Although overweight and obesity prevalence were relatively higher amongboys compared to that of girls in many studies the difference was mostly statistically insignificant.

Risk factors of overweight and obesityLack of physical activityEight studies examined the association between lack of physical activities and overweight/obesity in childhood and adolescence, of which six reported a significant positive association . The duration of activities ranged from less than 2 hours/week32 toless than 30 minutes/day. Although, two studies found no significant positive correlation between physical activities and overweight/obesity, one study found activities at home such as regular exercise for 30 minutes/day as a protective factor against overweight/obesity.The same study also noted a positive association between engaging in sedentary activities for more than 4 hours/day and overweight/obesity

Watching television and/or playing computer gamesOf the five studies that looked at associations between overweight/ obesity and long durations of watching television and/or playing computer games, four found a significant positive correlation with either or both of these factors. Theduration of these activities ranged from 2 to 4 hours/day. The reported odds of becoming overweight or obese ranged from 5.4 to 7.3 Although one study reported a positive association between shorter duration of watching television for 30 minutes/day, the association was not found to be statisticallysignificant.

Dietary intake patternThe association between dietary habits and overweight/ obesity was assessed in five studies of which two found significant associations between frequent consumption of calorie dense food items and overweight and obesity.Although another study found associations between high calorie intake and higher prevalence of childhood obesity, relationship was statistically insignificant. All the four studies that examined association between frequent consumption of fast food/junk food and the risk of overweight and obesity found a significant positive correlation. Mixed dietary pattern, involving high meat consumption, was examined as a risk factors for overweight/obesity in three Studies but none found a significant positive correlation.

Family history of obesityFour studies examined family history of obesity as a risk factor of which three found a significant positive association with overweight/obesity. Participants with at least one overweight parent were nearly three times more likely to become overweight or obese compared to those who hadnone, and obese children were nearly 50 times more likely tohave a family history of obesity

Socio-economic status (SES)Association between SES and overweight and obesity was evaluated in six studies, of which four reported a significant positive association between higher SES and overweight/ obesity.In general, different SES measures were used such as the Kuppuswamy classification, place of residence (urban/rural),monthly school fee, parent's education and occupation, wealth tertile using sociodemographic status, socio-economic stratification,maternal education and monthly family expenditure. One study reported that children and adolescents with higher SES and urban residence were 18 times more likely to become overweight or obese compared to those with low SES and rural residence.Although positive correlations between higher SES and increased prevalence of overweight and obesity was reported in the remaining two studies, they failed to establish the significance of the association.

DiscussionThe present review was undertaken to synthesize the evidence on key determinants of overweight and obesity among children and adolescents in South Asian countries. In spite of a comprehensive search, the authors could not find any other reviews focussing on this issue from the South Asia region or other developing regions, so this appears to be the first attempt in this direction.The review indicates that obesity and overweight among children and adolescents is an increasing problem in South Asia. This concurs with conclusions from other recent reviews that South Asia is significantly affected by the obesity epidemic. The review also identifies a number of contributors to overweight and obesity among children and adolescents in the region which are consistent with findings reported from other developing countries.

The review showed that lack of physical activity is one of the key factorsassociated with childhood obesity. Children who are likely to be involved in physical activities such as playing general outdoor games were less at risk of being overweight or obese. Scarcity of safe, open recreation spaces and play areas following rapid urbanization in South Asia region coupled with lack of time for parents to oversee their children's play time in an era of economic transition and increasing labour market participation could all be reasons for reduced play time for children. As indicated elsewhere, due to overriding concerns of safety on the roads along with higher use of mechanized vehicles, parents may also be reluctant to allow their children to walk or cycle to school. Lack of recreationalfunds in schools and the increasing pressure to perform academically has also been indicated as reasons for reductions in physical activity levels in schools in recent years

Technological advances and devices such as computer games and an array of widely accessible television channels in countries of the region appear to be resulting in long sedentary hours at home for many children and adolescents. This in turn appears to contribute to overweight and obesity as shown in the review. Long hours of watching television and playing video games have been reported as an independent risk factor of childhood overweight and obesity by other studies as well. Watching television for long hours also tend to promote high calorie snacking and/or tempting children towards calorie rich unhealthy foods with flashy advertisements.Some TV programs for children contain frequent advertisements of unhealthy soft drinks and energy dense food items. As came up in the review, and shown by other studies, obesity tend to run in families and children of overweightparents are at increased risk of being overweight or obese.

In many developing countries, overweight and obesity in general tend to be perceived as a sign of affluence of the family. The review indicated that children with higher SES are at increased risk of becoming overweight or obese. Similar findings were also reported in other studies from low andmiddle income countries. Over the past few decades, most of the developing countries have experienced improved socioeconomic status among its population, better health has been linked to access to resources. On the other hand, improved socio-economic status in low and middle income countriesmight mean the ability to afford a more mechanized, less labour intensive daily life routine, increased access to high calorie, fast food and a more sedentary life style in general.

Socio-economic status of the household has also shown to be associated with breastfeeding even though this wasn't included as a relevant factor in this study. While prolonged breastfeeding is associated with reduced adiposity in later childhoodhigher socio-economic status of the household is a contributory factor for early stoppage of breastfeeding in developing countires.It may be possible that better economic position brings in higher affordability of bottle milk andother breast milk substitutes and this coupled with a notion of ‘chubby’ babies as mark of affluence and health tend to lead to early stoppage of breast feeding.

The review has certain limitations, however. The selected studies were confined to three South Asian countries e India, Pakistan and Bangladesh e as no relevant studies were found from other countries in the region. This may limit the generalizability of the findings to the region as a whole. Individual studies were also confined to specific cities with participantscomprising of children and adolescents attending schools, and as such the studies may be limited in producing a nationally representative picture of the respective countries ontheir own. As indicated by recent reports, there are a total of 27 million children out of school in Bangladesh, India, Pakistan and Sri Lanka, of whom 17 million are of primary school-age and 9.9 million of lower secondary school-age.57 As most of the studies included in the review adopted a cross-sectionaldesign, the authors were unable to establish temporal associationbetween exposures and outcome, thus failing to confirm whether exposures preceded or followed outcomes as in case-control or cohort studies.

ConclusionThe review provides evidence of the increasing burden of obesity and overweight among children and adolescents in South Asia, and demonstrates a nutritional transition that characterizes other developing countries and regions around the world. Rapid urbanization replacing traditional farming to industry oriented food production and consumption of unhealthy energy-rich foods and increasing technology mediated sedentary lifestyle with decreasing physical activities allappear to contribute to increasing prevalence of childhood and adolescent overweight and obesity in South Asia. On the other hand, as mentioned before, most countries in the regioncontinue to have a high rate of under-nutrition among children, and this epidemiological paradox of malnutrition and over nutrition poses dual public health burden in the region.The nutrition transition which is a characteristic of many developing countries is argued to be visible not only at the country level, but also at community, household and individual levels.

The findings from this review have important implications for a range of stakeholders such as planners, policymakers, academics and researchers in public health and health policy at national, regional, and international levels towards combating the increasing problem of obesity and overweightamong children and adolescents. As in other developing countries, there have been several attempts to address the issue of malnutrition in the region, but the problem of obesityremains largely unrecognized. The identified contributors point to the need for a cross-sectoral approach involving interventions at various levels such as home, school and the wider community. The review also identifies a number of areas for future research. As mentioned before, although there is adequate evidence to show that childhood obesity and overweight is an increasing problem in the region, there is a dearth of nationally representative data from majority of thecountries in the region to inform concerted action to tackle theissue.

Acanthosis Nigricans Indian studies

• This simple diagnostic marker in a clinical examination in office practice was seen in seen in 20% of obese adolescents,

• who also had high insulin and C-peptide levels with normal HbA1c level

Subramaniam V, Jayashree R, Rafi M. Prevalence Overweight and obesity in Chennai 1981& 1998. Indian Pediatrics 2003; 40: 332-336.

KEY MESSAGES• India : alarming epidemic of T2 DM, CHD & other LSD

associated with the IRS (metabolic syndrome X). Ethnically, Indians have lower muscle mass and higher body fat (especially central obesity).

• The fetal origins hypothesis proposes : dysadaptation between fetal growth restriction (LBW ) & subsequent over nutrition (obesity).

• The FOAD epidemic is potentially preventable with life style changes in childhood and adolescence.

• Targeted effectively through school / college campaigns to focus on healthy eating, increased physical activity and reduction in sedentary habits.

Thank you