Indian Pediatrics 2003; 40:332-336 

Prevalence of Overweight and Obesity in Affluent Adolescent Girls in Chennai in 1981 and 1998

Key words: Adolescence, Obesity, Overweight, Prevalence.

India is undergoing a rapid epidemio-logical transition(1). The burden of chronic diseases is overtaking the burden of infectious diseases(2). In the year 1998, the World Health Organization designated obesity as a global epidemic(2).

Childhood obesity is related to adult levels of lipids, lipoproteins, blood pressure, insulin and, to morbidity from coronary heart disease(3). Overweight children are twice as likely as normal children to be obese adults. Evidence from a systematic review of risk factors for obesity showed, that the children with overweight or obese parents have a higher risk for obesity(4). Therefore, with almost 20% of South East Asia’s popula-tion being constituted by adolescents(5), there is an urgent need to know the burden of this problem in India. There has been no data on the prevalence of overweight/obesity in southern India. This study was done with this in view.

Subjects and Methods

This was a school based cross sectional study in the years 1981 and 1998 at Chennai. In 1981 the school selected was an English medium girls matriculation school run by Christian missionaries located in the heart of the city. This school had ample space for playground. Physical education formed part of their curriculum. Parents belonged to the higher economic status who could pay the school fees of about Rs. 500/- per month which at that period of time was considered high. In the year 1998, the school selected was an English medium girls matriculation school run by christian missionaries and was about 10 km from the school surveyed earlier. The students paid a school fees of about Rs. 2000/- per month and had ample opportunity to play. Parents were affluent economically.

These surveys were conducted basically to collect information regarding the sexual maturity ratings (SMR), menarcheal age and growth pattern during the various stages of sexual maturity. However, for this paper only the information of the girls between the ages of 10-15 years is being considered for analysis.

Consent from parents was obtained by the school authorities as per instructions from the principal investigator including the need to change into a gown. Surveyors were all women, consisting of three Senior House Officers and a Registrar – a different team for each of the survey. They were trained by the principal investigator. Principal investigator personally attended the survey.

Information regarding age was obtained from the school records and was also rechecked from each student. This was later converted into the decimal age(6,7). Time taken for the survey was two weeks in July of 1981 and 1998.

Balance beam type of weighing scale was used to record weight to the nearest 50 grams and each girl wore a gown of known weight(6,7). Height was measured in the 1981 survey with the inbuilt attachment for measur-ing height, provided in the balance beam type of weighing scale supplied by the UNICEF to the Department of Pediatrics, Kilpauk Medical College, Chennai. Whereas, a stadio-meter supplied by the Kabi Pharmacia Company was used in 1998. Each student stood straight with head held in Frankfurt horizontal plane.

Information was sorted out according to the decimal age and stored as physical records and later was transferred to computer for analysis.

BMI was calculated after the second survey by one of the authors. The BMI values were analyzed at exactly half yearly intervals and at percentiles 50th, 85th and 95th. 85th and 95th centiles were taken to correspond to overweight and obesity respectively(8,9). The first study done in 1981 constituted the group I while that conducted in 1998 was designated group II.

Results

There were 707 girls in Group I (1981) and 610 in Group II (1998), after exclduing 3 (with skeletal defects) in group I and none from group II between the ages 10-15 years (Table I). In Group I, overweight prevalence varied from 7.4% to 10.42% with two peaks at 11.5 and 12.5 years of age whereas in group II the prevalence range has been from 8.0% to 10.81% with three peaks at 10, 12.5 and 13.0 years (Table I). Obesity in group I ranged from 5.10% to 8.33% and peaked in 10, 13, and 15 years. In group II, range of obesity has been from 5.26% to 9.52% with peaks at 12 and 14.5 years. Overall, a greater proportion of overweight and obese adolescent girls were observed in the 12 to 14 years of age (Table I). Though overweight in adolescents is a reality (1981-9.62%, 1998-9.67%) the aggregate numbers did not show an increase between the two groups. The same was (1981-5.94%, 1998-6.23%) true for obesity also (Table I).

Table I
Prevalence of Overweight (85th percentile) and Obesity (95th percentile) in Adolescent
Girls - Chennai in 1981 and 1998

	Group I - 1981					Group II - 1998
		Over weight		Obese			Over weight		Obese
Age in years	Total surveyed	No.	%	No.	%	Total surveyed	No.	%	No.	%
10.0	41	4	(9.76)	3	(7.32)	37	4	(10.81)	2	(5.41)
10.5	104	10	(9.62)	6	(5.77)	105	9	(8.57)	7	(6.67)
11.0	31	3	(9.68)	2	(6.45)	42	4	(9.52)	3	(7.14)
11.5	98	10	(10.20)	5	(5.10)	103	10	(9.71)	6	(5.83)
12.0	34	3	(8.82)	2	(5.88)	25	2	(8.00)	2	(8.00)
12.5	96	10	(10.42)	5	(5.21)	95	10	(10.53)	5	(5.26)
13.0	27	2	(7.41)	2	(7.41)	28	3	(10.71)	2	(7.14)
13.5	125	12	(9.60)	7	(5.60)	82	8	(9.76)	5	(6.10)
14.0	24	2	(8.33)	2	(8.33)	19	2	(10.53)	1	(5.26)
14.5	86	8	(9.30)	5	(5.81)	21	2	(9.52)	2	(9.52)
15.0	41	4	(9.76)	3	(7.32)	53	5	(9.43)	3	(5.66)
Total	707	68	(9.62)	42	(5.94)	610	59	(9.67)	38	(6.23)

 

Body Mass Index (BMI) at the 50th percentile in Group I & II is shown in Table II. BMI above the 95th percentile in groups I & II upto the age of 13 years at yearly intervals is shown in Table III.

Table II
Adolescent Girls: BMI 50th Percentile in the Year 1981 and 1998, Chennai.

Age in years	BMI (1981)	BMI (1998)
10	15.03	15.09
11	15.60	15.40
12	16.23	17.67
13	16.87	16.68
14	17.62	16.89
15	19.34	19.91

 

Table III
Adolescent Girls: BMI above 95th Percentile in the Year 1981 and
1998 (Chennai and International Values).

Age in years	BMI (1981)	BMI (1998)	International reference standard
10	20.00	22.04	24.11
11	21.97	22.95	24.42
12	21.17	23.26	26.67
13	23.40	27.23	27.76

Discussion

Life style transition and economic improvement have contributed to the problem of adolescent obesity. It has been suggested that three stages of growth may be critical for the development of "persistent obesity" that influences co-morbidities in adulthood, namely, the prenatal period, the period of adiposity rebound 4-8 years of age, and adolescence(4). Adolescent girls gain more fat than muscle compared to adolescent boys and are at greater risk for becoming overweight. The distribution curve of overweight has become skewed to the right over time, indicating that children who are already overweight are getting fatter(10). Whether female adolescent obesity tracks to adulthood have been the subject of earlier studies(11). There are no deterministic views regarding this(10,11). However, a consistent observa-tion regarding female obesity seen at ages 9 and 13 years tracking to adulthood needs to be verified in the Indian context(10,12). We have also observed a higher BMI around age 13 years (Table III). Freedman et al.(4) with a mean follow up of seventeen years have found that an yearly average increase of 0.5 kg/m2 of BMI in children have adverse changes in risk factor levels for hypertension, heperlipidemia and type II diabetes mellitus. If this rate of increase in BMI and its relation to the risk factors as mentioned above, is applicable to our country, it would be a valuable means to detect overweight early.

For definition of overweight and obesity, the 85th and 95th centile of the BMI values have been in use(9). Recently, the International Task Force on Obesity has recommended the cut off values as 25 kg and 30 kg/m2 for overweight and obesity respectively, based on the data from many countries but, none was included from Asia and Africa(8).

An interesting observation was that the 50th percentile of BMI in the two groups had not shown any variation, meaning thereby, that the average adolescent girls in Chennai have not shown a change in the their BMI (Table II). Their BMI had ranged between 15 kg/m2 and 19 kg/m2 in both the groups of girls between the ages of 10-15 years.

Adolescents at the 95th percentiles of BMI in 1998 were heavier than the adolescents in these same percentiles of BMI in 1981, concurring with the findings of Edmunds et al.(10). At age 13 years their BMI parallelled the international estimate even though, at earlier ages their BMI were consistently lower than the international estimates.

Almost 10% of the studied population were overweight and 6% have been obese. However, there was no statistically significant change in the prevalence of this problem in the two surveys in Chennai.

The limitations in this tudy are, that it is not a community based study and the number of children in some age groups are small. All the same, the prevalence of overweight and obesity in adolescent girl population is evident.

Acknowledgement

Dr. Sreelatha R and team for the survey of the year 1981. Dr. Shanti Ramesh and team for the survey of the year 1998. Dr. Shafi Ahamed S. for statistical guidance. Mr. Shankar, Head, Electronic data processing department of Kanchi Kamakoti Childs Trust Hospital, for streamlining the data for statistical analysis. Prof. N. Deivanayagam, Clinical Epidemiologist, Chennai for assist-ance in epidemiological evaluation.

Contributors: VS conceived, designed and conducted both the surveys. She coordinated data preservation and later analysis and will act as guarantor for the work and manuscript. JR assisted in the primary manuscript preparation and preliminary data analysis. MR calculated all the BMI and assisted in the preliminary data analysis.

Funding: None.

Competing interests: None stated.

 References