










Lifestyle intervention as a treatment for obesity among
school-age-children in Celaya, Guanajuato: An experimental study


Lifestyle intervention as a treatment for obesity among
school-age-children in Celaya, Guanajuato: An experimental study

Nicolas Padilla-Raygoza1, Rosalina
Diaz-Guerrero2, Ma. Laura Ruiz-Paloalto3




1Department of Nursing and Obstetrics, Health
Sciences and Engineering
Division, Celaya-Salvatierra Campus, University of Guanajuato,
2Department of Clinical Nursing, Health Sciences
and Engineering
division, Celaya-Salvatierra Campus, University of Guanajuato,
3Division of Health Sciences and Engineering,
Campus Celaya
Salvatierra, University of Guanajuato




Abstract



Introduction:
Obesity is a risk factor in chronic diseases, and its
frequency among children in Mexico is increasing. Objective: To
determine the effect of lifestyle intervention as a treatment for
obesity in school-age-children from Celaya, Mexico.




Methodology:
For this experimental study, four schools were randomly
selected. Children and parents participated voluntarily and signed
consent forms. Two schools were chosen as the experimental group and
the other two formed the control group. Age, gender, weight, height,
BMI and blood pressure were recorded for each participant.




Intervention:
Children and parents were asked to walk in their schools
for 30 minutes a day Monday through Friday and to attend 8
instructional sessions over a period of four months dedicated to the
selection and preparation of meals. Statistical Analysis: The OR and
95% CI were calculated to determine the effect of the intervention; a
Z-test for two proportions for overweight and obesity in the control
and experimental groups were carried out for comparison.




Results:
157 children were included in the experimental group and 144
in the control group. To compare the proportions of the overweight and
the obese between the groups, a Z-test = - 0.36 (p-value 0.72) were
obtained showing no effect of the intervention in lifestyle; OR =1.09,
95% CI (0.67, 1.77). It was adjusted according to the attendance to the
sessions resulting in an OR = 2.00, 95% CI (0.69, 5.77), demonstrating
that not attending the sessions was a confounder.




Conclusions:
Intervention in lifestyle should be measured over a longer
period of time in order to determine what effects it may have on
changes in body mass index.




Keywords: hypertension; physical activity; meals




Introduction




Obesity is a chronic condition that contributes to many diseases and
affects more children and adolescents each day. One of the most
important concerns is the emergence of type-II diabetes and metabolic
syndrome at earlier ages.1



Obesity is the result of an imbalance between energy consumption and
expenditure due to diets high in caloric density and low in fiber, as
well as high consumption of sugary drinks accompanied by little or no
physical activity.2



In Mexico, according to the National Surveys on Health and Nutrition,
the frequency of obesity in male and female children and adolescents
has increased from 18.6% in 1999 to 26% in 2006, The percentage of
overweight children and adolescents has also increased from 12.9% in
1999 to 21.2% in 2006.3,4



In the United States, the Centers for Disease Control and Prevention
(CDC) is also concerned with this issue. Their studies show that no
state reported an obesity rate above 15% in children and adolescents in
1990, but in 1995 more than half the states reported an obesity rate
between 15 and 19 %. By the year 2000, over 22 states had rates higher
than 20%, and in 2005 17 states had rates above 25%.5



From 2003 to 2004, the National Health and Nutrition Examination Survey
(NHANES) reported that 33.6% of children and adolescents had some
degree of obesity; 17.1% were obese and 16.5% at risk of obesity.6



Early weaning, increased intake of processed foods with a high caloric
density, a decrease in consumption of low caloric density foods (fruits
and vegetables), urbanization, mechanization of transport and use of
technology, a decrease in energy expenditure, less time spent on
leisure activities, and decreased time and intensity in physical
education and sports at school all contribute to obesity at an early
age.3



An obese patient is 2.5 times more likely to develop coronary heart
disease, 4 times more likely to develop hypertension, 3-4 times more
likely to develop type-II diabetes and at 5 times higher risk of stroke
than a person with a BMI in the normal range.7



The percentage of newly-enrolled elementary school students in Mexico
who are obese has increased by a factor of three, suggesting that
approximately 26% of Mexican children reach obesity before the onset of
puberty.3



The effects of obesity and being overweight among children are
numerous, leading to conditions such as: glucose intolerance, insulin
resistance, type-II diabetes, hypertension, dyslipidemia, hepatic
steatosis, sleep apnea, orthopedic problems, low self-esteem, negative
body image and depression, discrimination, negative stereotypes,
anorexia and bulimia, among others. These effects prove an overwhelming
burden to the healthcare system.



Therefore, we must seek strategies to prevent or decrease the number of
obese and overweight children.



The objective of this study was to apply an educational and physical
activity intervention program to treat or prevent increased weight in
order to lower the frequency of this syndrome in school age children
from Celaya, Guanajuato, Mexico.



We developed the following hypothesis:
Children in the experimental group will have a 10% decreased frequency
of overweightness/obesity compared with the control group.




Materials and
Methods




The protocol was reviewed and approved by Bioethics Committee from the
School of Nursing and Obstetrics of Celaya, University of Guanajuato.



Type of study: This prospective, controlled,
longitudinal study was
carried out in public elementary schools from Celaya, Guanajuato,
Mexico.




Population: Male and female school-age-children,
enrolled in Celaya
public elementary schools incorporated to the Guanajuato Ministry of
Education.



Inclusion criteria: Children 6 to 13 years old, male
or female enrolled
in public elementary schools, whose parents accepted their
participation in the study by signing the corresponding consent form.



Exclusion criteria: Children with diseases that
inhibited physical
activity, children whose parents did not sign the consent form, and
children over the age of 8 who did not consent.



Sampling: Four schools were selected at random from
the 168 existing
public schools in Celaya in 2007. Two schools randomly formed the
experimental group and the other two were the control group. At each
school, parents were invited to an informative meeting where the
objectives of the study were explained. Parents were asked to sign a
consent form allowing their children to participate in the study.
Children 8 or older were asked to sign an additional form demonstrating
their own wish to participate. All participants answered questions in
reference to their age, gender, residence, and socioeconomic level
(SELI).8 Participants were weighed using the
Medidata Serie MS ®
digital scale. They wore only essential clothing and did not wear
shoes. They stood on the scale looking forward while both weight and
height appeared on the screen of the scale. Blood pressure was measured
3 times using a digital monitor. The average of the three readings was
calculated. A correlation between measurements was established by
measuring the blood pressure of 30 children using a digital and a
mercurial monitor (adjusting the cuff to the age of the participant).
The correlation was r= 0.79.




Body Mass Index (BMI) was calculated by dividing weight in kilograms by
height (in centimeters) squared. The mothers of the children answered a
questionnaire on food habits (SNUT)9 and a
software was used to process
the SNUT and obtained the daily average of calorie consumption.
All measurements were carried out at the beginning of the study and at
sixteen weeks. The results found in the control and experimental groups
were used to define the impact of the lifestyle intervention program.




Intervention: It was decided that the lifestyle
intervention program be
administered at the schools to avoid contamination of the control group
by the experimental group in a non-school
environment.



The lifestyle intervention program in the experimental group had two
phases:



Phase 1: All school-age-children,
whose parents agreed to participate in the study, had monitored
30-minute walking sessions at school from
Monday through Friday where attendance was checked. To maximize the
participation in the walking sessions, they were carried out at the end
of their school day (12:30 PM).




Phase 2: 8 instructive sessions with the
children´smothers were
carried out. In these sessions, mothers were taught to prepare and
select healthy meals for their children. The sessions took place every
two weeks throughout the 16 weeks of the study. Two nutritionists were
in charge of the sessions. Table 1 shows the descriptive content of the
sessions. Attendance was checked at each session.



Table 1: Descriptive chart of contents from instructional
sessions with mothers to help to select and prepare meals, Celaya, Gto.
2009


	Session
	Topic
	Objective
	Teaching
Strategy
	1	Growth and development	To know the importance of foods in childhood 	Lecture with slides
	2	Nutrients needed for growth and development	To recognize which are the most important nutrients for
growth and development in children	Lecture with slides
	3	Foods groups	To familiarize mothers with the food groups for an
appropriate nutrition.	Workshop style and collaborative group work. 
	4	Food portions	To recognize the appropriate food portions for each
child.	Workshop style and collaborative group work. 
	5	Practical advice	To learn practical ways to get your child to eat
healthy meals.	Lecture with slides
	6	Myths and realities about feeding	To answer frequently asked questions about child
nutrition.	Lecture with slides
	7	Food preparation workshop I	To empower mothers in preparing nutritious meals.	Preparation and tasting of healthy meals
	8	Food preparation workshop II	To empower mothers in preparing nutritious meals.	Preparation and tasting of healthy meals






Follow-up: After sixteen weeks, anthropometric
measurements and blood
pressure were measured. The SNUT survey was then applied to both the
experimental and control groups.
The control group did not receive any lifestyle intervention. However,
after the study was over, a meeting was held with the mothers of the
control group to instruct them on the advantages of physical activity
and selection and preparation of healthy meals as preventive measures
to avoid overweight/obesity. This was done in order to meet the
bio-ethical principles of justice.



Outcome measurements: “Overweight” was defined as a
BMI between the
75th and 84th percentile in accordance with the CDC 2000 curves by age
and gender”.10 “Obesity” was defined as a BMI in
the 85th-96th
percentile in accordance with the CDC 2000 curves, by age and
gender”.10 “Severe obesity” was defined as a BMI
above the 97th
percentile in accordance with the CDC 2000 curves, by age and
gender”.10 “Hypertension” was defined as
pressure levels higher than
the 95th percentile in the blood pressure charts, by gender, age and
height”.11



Sample size: The expected proportion of
overweight/obese was 26% in the
control group and 16% in the experimental group. The minimum sample
size with a 95% of precision and an 80% of power is 101 in each group.
An increase to 150 should be considered due to conglomerate sampling
(design factor 1.5) (EpiInfo 2000 version 1.1 CDC, Atlanta, GA, EUA).



Statistical Analysis: Children were classified as
overweight/obese, or
appropriate weight. Another classification was hypertensive or with
appropriate blood pressure. The proportion of overweight/obese in each
group was compared with the Z-test and p-value to test the hypothesis.
The same test was used to compare rates of hypertension between the
experimental and control groups. To measure the effects of the
lifestyle intervention program, the Odds Ratio (OR) and 95% Confidence
Intervals (CI) between groups were calculated for overweight/obese and
for hypertension. It was adjusted in accordance with the attendance to
the walking sessions and the preparation and selection of meals
sessions.



As a second step, the subjects were classified by status of obesity:
low/adequate weight, overweight, obese, and severely obese. Proportions
between the experimental and control group were compared with the
Z-test for two proportions and p-value.



Using a Chi-squared test and p-value, tabulation was elaborated
comparing the status of hypertension and the status of obesity to
determine if there was a relationship between variables.



Mean differences in weight, height, BMI, systolic blood pressure,
diastolic blood pressure, and daily calorie intake before and after the
intervention were calculated with the Z-test and p-value.



In all cases, the p-value used to demonstrate statistical significance
was 0.05. All statistical analysis was calculated using STATA 10.0®
(Stata Corp, Texas, EUA).



Results




400 parents from the 4 selected schools were invited to attend the
informational meetings. Among these 400 parents, 297 (74.25%) permitted
their children to participate in the study and signed the consent form.
The experimental group was comprised of 157 children and the control
group of 144.



Qualitative baseline characteristics in each group are shown in Table
2.



Table 2: Qualitative baseline characteristics of both groups,
Celaya,Gto., 2009 (n= 301)

	Variables	Experimental
Group

n=157	Control
Group

n=144


		n	%	n	%


	Age Group (years)		


	6-8	78	49.68	61	42.36
	9-11	67	42.68	75	52.08
	12-14	12	7.64	8	5.56


	Gender


	Male	90	57.32	68	47.22
	Female	67	42.68	76	52.78


	SELI


	Low	0	0	1	0.69
	Regular	11	7.01	8	5.56
	High	136	92.99	135	93.75


Source: questionnaires from this study


SELI = Socioeconomic level index




In terms of age, X2 = 1.16, df = 2, p = 0.6,
point to no significant
difference in the groups. In terms of gender, there was also no
significant difference among groups with X2 =
2.68, df = 1, p = 0.1. In
terms of the socioeconomic level index, the Z-test for two proportions
between height (SELI), was Z = 0.03, p = 0.97.



In the walking sessions, the mean of the absences of children was
2.71±1.25 and in the instructional sessions for mothers on selecting
and preparing the children’s meals was 14±0.35. No participant had more
than 20% absence in both activities.



Table 3: Attendance to walking sessions and instructional
sessions in
to select and prepare meals in experimental group, Celaya, Gto, 2009
(n=154)
		n	%


	Absences in
Walking Sessions


	0	2	1.30
	1	24	15.58
	2	42	27.27
	3	50	32.47
	4	25	16.23
	5	7	4.55
	6	3	1.95
	7	1	0.65


	Absences to Instructional Sessions


	0	132	85.71
	1	22	14.29


Source: checklist of attendance




Table 4 shows the quantitative baseline characteristics between the
experimental and the control groups. The Z-test was calculated for two
independent means. In terms of age, the average difference was Z =
-0.47, p = 0.64; in terms of weight in kilograms, the average
difference was 1.85 with Z = 1.24 and p = 0.2. Height was measured in
meters and the difference was 0 with Z = 0 and p = 1.0. The differences
in these variables were not statistically significant. On the other
hand, when measuring systolic blood pressure in mm Hg, the difference
was 4.96, with Z = 3.18, p = 0.001. The difference in diastolic blood
pressure was 4.45 with Z = 3.45, p = 0.0006; in terms of BMI, the
difference in the mean was 1.21 with Z = 2.25, p = 0.03. With regards
to daily consumption of calories, the average difference was 465 with Z
= 4.88, p = 0.0000. These differences were statistically significant.



Table 4: Quantitative baseline characteristics of both
groups,
Celaya,
Gto., 2009 (n=301)
	Variables By Group	Range
	Mean ± SD



	Age (in years)


	Experimental (n=157)
	6 to 13	8.74 ± 1.93
	Control (n=144)
	6 to 13	8.84 ± 1.73


	Systolic Blood Pressure (mmHg)


	Experimental (n=157)
	80 to 100	115.06 ± 16.03
	Control (n=144)
	85 to 155	110.12 ± 10.68


	Diastolic Blood Pressure (mmHg)


	Experimental (n=157)
	42 to 125	75.24 ± 12.44
	Control (n=144)
	46 to 122	70.79 ± 9.59


	Weight (kg)


	Experimental (n=157)
	17.850 to 84.950	37.28 ± 13.87
	Control (n=144)
	17.800 to 76.950	35.43 ± 12.79


	Height (Mt)


	Experimental (n=157)
	0.82 to 1.64	1.32 ± 0.13
	Control (n=144)
	1.06 to 1.61	1.32 ± 0.12


	Body Mass Index (Kg/m2)


	Experimental (n=157)
	13.52 to 42.24	20.88 ± 4.84
	Control (n=144)
	13.49 to 33.75	19.67 ± 4.47


	Mean of Daily Calorie Consumption


	Experimental (n=157)
	1471.23to 6909.62	2803.75 ± 859.52
	Control (n=144)
	755.05 to 6049.45	2338.29 ± 790.80


Source: Questionnaires of study, SNUT survey


SD = Standard deviation




Three children from the experimental group (1.9%) and two from the
control group (1.4%) decided to drop out from the study.



To test the hypothesis of comparing the proportions of the
overweight/obese between experimental and control groups, a Z-test
resulting in -0.36 was calculated and p = 0.72. This demonstrates that
there is no significant statistical difference between both groups and
that the lifestyle intervention program had no effect, with OR = 1.09
and
a 95% CI = 0.67 to 1.77.



When adjusting the OR with absences to the walking and instructional
sessions on selecting and preparing meals, the OR adjusted was 2.00 [CI
95% (0.69, 5.77)], showing that the attendance to the walking sessions
and instructional sessions were factors of confusion.



Proportions of overweight/obese children, BMI, and hypertension were
compared before and after the intervention program.



Table 5: Comparison before and after intervention by
overweight/obesity
status and hypertension, Celaya, Gto, 2009 (n=301)
		Before	After	Difference
of Proportions	Z	p-value
	n	%	n	%
	Experimental
	Overweight/Obesity	115	73.25	100	64.94	0.0831	1.59	0.11
	Without
Overweight/Obesity	42	26.75	54	35.06	-0.0831	-1.59	0.11
	Control
	Overweight/Obesity	84	58.33	95	66.90	-0.0857	-1.50	0.13
	Without
Overweight/Obesity	60	41.67	47	33.10	0.0857	1.50	0.13
	Experimental
	Severe Obesity	60	38.22	40	25.97	0.1225	2.31	0.02
	Obesity	35	22.29	45	29.22	-0.0693	-1.40	0.16
	Overweight	20	12.74	15	9.74	0.03	0.84	0.40
	Without Overweight	42	26.75	54	35.06	-0.0831	-1.59	0.11
	Control
	Severe Obesity	34	23.61	32	22.54	0.0107	0.21	0.83
	Obesity	36	25.00	37	26.06	-0.0106	-0.21	0.83
	Overweight	14	9.72	26	18.31	-0.0859	-2.09	0.04
	Without Overweight	60	41.67	47	33.10	0.0857	1.50	0.13
	Experimental
	Hypertension	20	12.74	0	0	0.1274	4.58	0.0000
	Without Hypertension	137	87.26	154	100.0	-0.1274	-4.58	0.0000
	Control
	Hypertension	4	2.78	1	0.70	0.0208	1.34	0.18
	Without Hypertension	140	97.22	141	99.30	-0.0208	-1.34	0.18


Source: Questionnaires of the study




Statistically significant differences were found in the hypertension
category in the experimental group, in the overweight/obesity category,
and in the BMI categories (p<0.05).



In pre and post-intervention analysis of the quantitative variables, we
calculated the differences between the first and the second
measurements, the mean of the differences, the standard deviation, the
paired t-test, and p-value.



Table 6: Comparison of quantitative parameters pre and
post-intervention, per group, Celaya, Gto, 2009 (n=301)
		Before	After	δ ± sd	t-paired 	Df	p-value
	Mean ± s	Mean ± s	(IC95%)
	Weight(kg)
	Experimental	37.28±13.87	38.39±13.93	-1.25±1.23

(-1.45 to -1.05)	-12.61	153	0.0000
	Control	35.43±12.79	38.05±14.77	-2.75±5.89

(-3.73 to -1.77)
	-5.56	141	0.0000
	Height(Mt)
	Experimental	1.32±0.13	1.35±0.14	-0.04±0.02

(-0.04 to -0.036)
	-24.82	153	0.0000
	Control	1.32±0.12	1.34±0.13	-0.02±0.06

(-0.04 to -0.037)
	-23.83	141	0.0000
	BMI
	Experimental	20.88±4.84	20.41±4.59	-0.46±0.96

(-0.61 to -0.31)	-5.95	153	0.000
	Control	19.67±4.47	20.09±4.33	-0.45±1.65

(-0.72 to -0.18)	-3.25	141	0.001
	SAT(mmHg)
	Esperimental	115.06±16.03	109.97±8.69	5.05±14.85
(2.69 to 7.41)	4.22	153	0.0000
	Control	110.12±10.68	112.14±8.25	-1.95±7.64
(-3.22 to -0.68)	-3.04	141	0.003
	DAT(mmHg)
	Experimental	75.24±12.44	71.86±6.24	3.21±11.88
(1.32 to 5.10)	3.35	153	0.001
	Control	70.79±9.59	72.69±5.68	-1.81±8.96
(-3.30 to -0.32)	-2.41	141	0.017
	MDIC
	Experimental	2803.75±859.52	1988.41±639.51	803.25±879.42
(663.25 to 943.25)	11.33	153	0.0000
	Control	2338.29±790.80	2502.67±661.65	-164.16±522.91
(-250.91 to -77.41)	-3.74	141	0.0003


BMI= Body mass index 

δ± sd Mean of differences ± standard deviation

SAT= systolic blood pressure 

DAT= diastolic blood pressure 

MDIC= Mean daily intake of calories




In terms of weight, a significant statistical difference was found
between the groups (p < 0.05). For height, differences between
the
experimental and the control group were statistically significant as
well (p < 0.05). The same was obtained in the BMI (p <
0.05),
in systolic blood pressure (p < 0.05), and in diastolic blood
pressure (p < 0.05) for both groups; and the same was obtained
for
the average of daily consumption of calories in the experimental and
control group (p < 0.05) (Table 6).



Discussion




The sample of schools was obtained by random selection, which helps
control for potential bias; however, the children participating were
invited to partake. This introduces a possibility of bias since the
parents that were interested in the study and accepted the invitation
to participate probably had obese children. Evidence for this can be
seen in the difference in baseline values between groups (Table 4).



3 subjects (1.9% of the group) from the experimental group and 2 (1.4%
of the group) from control group decided to drop out of the study, but
this did not affect the analysis of the data.



Results obtained from this study do not support the hypothesis that
children in the experimental group will have a 10% decrease compared
with the control group (Table 5).



The percentages of 64.94% in the experimental group and 66.90% in the
control group were higher than those reported by the National Survey on
Health and Nutrition in Mexico during 2006 of 26%4.



115 (73.25%) children in the experimental group were already overweight
/ obese before the lifestyle intervention program began. After the
intervention program only 100 (64.94%) children were overweight /
obese. Although this may not be statistically significant, there was a
substantial decrease in this particular group. The control group
started out with 84 (58.33%) children that were overweight / obese and
after the 16 weeks it increased to 95 (66.90%) children. (Table 5).



It can also be observed that obese and overweight children in the
experimental group lost weight after the lifestyle intervention program
(p < 0.05), and that the number of children with appropriate
weight increased. This demonstrates, in a way, that our lifestyle
intervention program was effective. In the control group, the number of
students with appropriate weight decreased from 60 to 47 (p >
0.05) and the increase in overweight school children was statistically
significant (p < 0.05) (Table 5).



An important and unexpected finding was the frequency of hypertension,
12.74% in the experimental group and 2.78% in the control group, since
in Mexico the hypertension rate is considered to be at 1% in
children.12 In the experimental group, it was
detected that after 4
months of the application of the intervention program, there were no
children with hypertension in the experimental group and only 1 child
with hypertension in the control group (Table 5). These results could
be biased because in the first visit, the children were unfamiliar con
observers and maybe they felt stress; this could decrease after 16
weeks. Steinberger et al. reported an association between obesity and
hypertension in children and adolescents13.
Physical activity at least
30 minutes, 3 times/week, reduces blood pressure in youth with mild
essential hypertension.14



The intervention of physical activity and adequate preparation and
selection of meals proved to be effective. The experimental group
showed an average increase of 1.25 Kg, in weight; whereas the control
group had an average increase of 2.75 Kg after the four months of the
study. There was also a change in height after the follow-up time, but
this may be due to the natural growth of the children. (Table 6).



Average difference in BMI was similar; 0.45 in the experimental group
and 0.46 in the control group, (Table 6).



Systolic blood pressure in the experimental group had an average
decrease of 5.05 mmHg after the lifestyle intervention program, while
in the control group it increased 1.95 mmHg. There were also
differences in the diastolic blood pressure; the average decrease in
the experimental group was 3.21 mmHg; there was an average increase of
1.81 mmHg in the control group (Table 6). Even though the analyses
performed before and after the intervention program were statistically
significant for both groups, the results were less significant in the
experimental group as compared to the control group. It must be pointed
out that the experimental group showed positive differences in systolic
and diastolic blood pressure, indicating the second measurements were
lower than the first measures. In contrast, the control group had a
negative difference, indicating that the second measurements were
higher than the first (Table 6).



Average daily calorie intake decreased by 823 calories in the
experimental group, while the control group increased their intake by
164 calories (Table 6). Even though in the analyses made before and
after the intervention program for both groups were statistically
significant, the experimental group showed positive differences for
daily mean intake of calories, indicating that the second measurements
were lower than the first measures. In contrast, the control group had
a negative difference, indicating that the second measurements were
higher than the first (Table 6).



Klesges et al. monitored a group of females for 2
years whom were
following an intervention program designed to prevent obesity. The
major foci of the program were: drinking more water, increasing the
consumption of vegetables and fruits, and lowering the intake of
sweetened beverages. They measured the BMI of the experimental and
control groups and significant differences were not found.15
The
intervention program in our study lasted four months. BMI was slightly
modified in the experimental and control groups but the change was not
statistically significant.



The World Health Organization recommends that changes in lifestyle
(such as increased physical activity) is an important part in the
prevention and treatment of hypertension and also helps in the
treatment of obesity.16,17



Conclusions



The null hypothesis could not be rejected because the differences in
proportions of school children with in the experimental and control
group were not statistically significant.



With physical activity intervention and changes in the selection and
preparation of meals, the number of children with hypertension
decreased.



Both increased physical activity and changes in food selection and
preparation should be studied over a longer period of time because four
months did not show sufficient effect on BMI. An important effect of
the intervention was a decrease in blood pressure.



These results warrant further investigation of the effects of healthy
lifestyles on changes in BMI in school children because of the
far-reaching benefits that may come from improving the health of young
people.



Acknowledgements



Thanks to PROMEP from the Ministry of
Education in Mexico, for the support for this study with
the 103.5/08/5163 grant; also, thanks to
Antonia
Vazquez Raya y Carolina Trejo Mancera for their help
in this study.



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