Obesity, overweight, screen time and physical activity in Mexican ...

Obesity and screen time in adolescents
Original article
Obesity, overweight, screen time
and physical activity in Mexican adolescents
María del Carmen Morales-Ruán, MSc,(1) Bernardo Hernández-Prado, DSc,1) Luz María Gómez-Acosta, MSc,(1)
Teresa Shamah-Levy, MSc,(1) Lucía Cuevas-Nasu, MSc.(1)
Morales-Ruán MC, Hernández-Prado B,
Morales-Ruán MC, Hernández-Prado B,
Gómez-Acosta LM, Shamah-Levy T, Cuevas-Nasu L.
Gómez-Acosta LM, Shamah-Levy T, Cuevas-Nasu L.
Obesity, overweight, screen time
Obesidad, sobrepeso, tiempo frente a la pantalla
and physical activity in Mexican adolescents.
y actividad física en adolescentes mexicanos.
Salud Publica Mex 2009;51 suppl 4:S613-S620.
Salud Publica Mex 2009;51 supl 4:S613-S620.
Abstract
Resumen
Objective. To determine whether screen time and physical
Objetivo. Determinar si el tiempo que los adolescentes
activity is related to overweight or obesity in adolescents.
permanecen frente a pantalla y realizan actividad física se
Material and Methods. Cross-sectional design. Adolescents
asocia con el sobrepeso o la obesidad. Material y métodos.
aged 10 to 19 were included in the Mexican National Health
Diseño transversal. Se incluyeron adolescentes de 10 a 19
and Nutrition Survey 2006 (ENSANUT 2006). The dependent
años de edad, de la Encuesta Nacional de Salud y Nutrición
variable was overweight or obesity; the independent variable
2006 (ENSANUT 2006). La variable dependiente fue el so-
was screen time. A logistic regression model was created to
brepeso u obesidad y la independiente el tiempo frente a la
estimate the relationship of overweight and obesity to vari-
pantalla. Se ajustó un modelo de regresión logística para esti-
ous factors, including screen time, physical activity, study vs.
mar la relación entre el sobrepeso u obesidad con el tiempo
no study, age, sex, indigenous ethnicity, alcohol consumption
frente a la pantalla, actividad física, edad, sexo, condición de
and tobacco use. Results. A total of 18 784 adolescents
estudiante, indigenismo, tabaquismo y consumo de alcohol.
were included. A positive relation between screen time and
Resultados. Se estudió a 18 784 adolescentes. Se encontró
overweight and obesity was found. Conclusions. Screen
una asociación positiva entre el tiempo frente a pantalla y
time is associated with overweight and obesity in Mexican
el sobrepeso u obesidad. Conclusiones. El tiempo que los
adolescents.
adolescentes mexicanos pasan frente a pantal a está asociado
con el sobrepeso u obesidad.
Key words: overweight; obesity; television/utilization; ado-
Palabras clave: sobrepeso; obesidad; televisión/utilización;
lescents; Mexico
adolescentes; México
(1) Instituto Nacional de Salud Pública. Cuernavaca, Morelos, México.
Received on: April 11, 2008 • Accepted on: February 25, 2009
Address reprint requests to: Ma. del Carmen Morales Ruán. Centro de Investigación en Nutrición y Salud, Instituto Nacional de Salud Pública.
Av. Universidad 655, col. Santa María Ahuacatitlán. 62100 Cuernavaca, Morelos México.
E-mail: cmruan@insp.mx
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Original article
Morales-Ruán MC et al.
Obesity is a worldwide health problem. In 2005, the Subjects: Our sample consisted of adolescents aged 10
WHO estimated that 1 600 mil ion people exceeded
to 19 living in selected homes at the time of the survey.
normal weight.1 Obesity is a risk factor for the develop-
Informed consent was obtained from the head of the
ment of chronic diseases and is increasingly observed
family and verbal consent was obtained from adoles-
among adolescents and children.
cents after the researchers explained the purpose of the

The majority of the 150-200 million children with
survey and the nature of the measurements to be taken
excess weight worldwide live in developing countries.2
from the adolescents. Study procedures were approved
According to the Mexican National Health and Nutrition
by the Research, Ethics and Biosafety Commissions of
Survey 2006 (ENSANUT 2006), 31.1% of Mexican male
the National Institute of Public Health (INSP).
adolescents and 32.5% of Mexican female adolescents
aged 12 to 19 are overweight or obese.3
Outcome measurements

Several studies have noted that obesity or over-
weight during childhood or adolescence increases the
Overweight and obesity. Height and weight were mea-
risk of obesity in adulthood4,5 and that obesity that
sured and used to calculate body mass index (weight in
begins in adolescence and continues into adulthood
kilograms/height in meters2). Weight was determined
increases morbidity and mortality risks.6-8 Moreover,
using Tanita electronic scales with 100 g accuracy. Height
obesity in adolescence may negatively impact self-
was measured using Dynatop anthropometers with a
image, resulting in low self-esteem and depression,9-11
capacity of 2 meters and accuracy to 1 mm. Standard-
social discrimination and difficulty in performing physi-
ization procedures using the Habitch technique24 were
cal activities.
established beforehand to minimize errors.

Strong determinants for overweight and obesity

Classification into overweight and obesity was
include a diet rich in fat and high calorie foods,12,13 with
made according to the International Obesity Task Force
inadequate fresh fruit and vegetable intake,14 limited
(IOTF) proposed distribution and cutoff-points.25 Nine
physical activity15 and increased TV viewing time.16-19
adolescents with BMI under 10 or above 58 k/m2 were
Watching TV for long hours may lead to an increased
excluded from the analysis. The dependent variable in
risk of obesity both through reduction of energy use and
this study was overweight plus obesity.
changes in diet.20

TV viewing time and a higher prevalence of obesity
Exposure measurements
have been documented in a US population,21 and to a
lesser extent in a Mexican population.22 While there is
Physical activity and screen time: Information on the
some evidence for this association in Mexico, there is
number of hours per week adolescents spent engaging
currently no research focusing on Mexican adolescents.
in active or passive activity was collected using a semi-
This study aims to determine whether screen time and
quantitative questionnaire. This instrument is based
physical activity are related to overweight and obesity
on the Youth Activity Questionnaire developed and
in a nationwide sample of Mexican adolescents.
validated in adolescents aged 10 to 14 from low and
middle income populations in Mexico City.26
Material and methods

Screen time was defined as time spent viewing
television, videos, or playing video games in TV or
Design: ENSANUT 2006 is a cross-sectional probabilistic
computers.
survey, representative at national, regional and state

Vigorous physical activity was defined as activity
levels in Mexico. This survey utilized a stratified mul-
requiring an energy expenditure > 6 MET/hour* (meta-
tistage sampling design. Basic Geographical Statistical
bolic equivalent), including playing soccer, basketball,
Areas (BGSAs) were selected in the first sampling stage.
vol eybal , practicing karate or other martial arts, riding
In a second stage, six blocks were selected at random for
a bicycle, skating or skateboarding, dancing or taking
each of the BGSA with a probability proportional to the
dancing lessons, swimming, and other games and sports
number of homes. Subsequently, in each of the blocks
a selection of six houses was chosen using systematic
random sampling. In each of the houses, using simple
random sampling, an adult, an adolescent, a child and
a user of health services were chosen to answer the
* A unit of metabolic equivalent (MET) represents a multiple of the
questionnaires. General methods for ENSANUT 2006
oxygen consumption at rest, which in turn corresponds to 3.5 mL
O
have been described elsewhere.23
2/kg min-1. For example, if a person exercising expends 10 MET,
that is 10 times the amount of oxygen consumed when at rest.
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Obesity and screen time in adolescents
Original article
requiring running or physical exertion; moderate physi-
6.99 hours of physical activity per week were consid-
cal activity was defined as activity requiring energy
ered moderately active, and those reporting less than
expenditure of 3.0 to 6 MET/hour including cleaning
4 hours of moderate or vigorous physical activity per
the house, walking (including walking to school) with
week were considered inactive.
weight (for example, a schoolbag).27 Sedentary/light

Additional y, an index including both physical
activities were defined as those requiring minimal en-
activity time and screen time was created to describe
ergy expenditure (< 3 MET/hour) including watching
categories of activity: adolescents who reported screen
TV, films, videos, or playing videogames.
time of 21 or more hours per week and performing less
than 4 hours of moderate or vigorous physical activity
Covariates
were described as very passive; those reporting screen
time less than 7 hours and performing less than 4 hours
Socio-demographic characteristics: Information on age,
of physical activity were categorized as moderately pas-
urban or rural place of residence, and indigenous eth-
sive; adolescents with screen time less than 7 hours and
nicity (using as proxy whether the head of the family
performing moderate to vigorous physical activity more
spoke an indigenous language) was col ected at the time
than 7 hours per week were classified as very active, and
measurements were taken. A socioeconomic status index
those with screen time more than 21 hours per week but
was constructed using variables on dwel ing conditions,
performing more than 7 hours of physical activity per
possession of appliances and other goods,28 and catego-
week were regarded as slightly active.
rized in tertiles (low, medium, high).

A logistic regression model was fit to estimate the
Studying at present: Adolescents were asked whether
relationship between being overweight or obese and
they were students at the time of the survey.
screen time and one was fit to estimate the relationship
Habits on alcohol consumption and tobacco use: Adolescents
between being overweight or obese and its associa-
were asked whether they smoked or drank alcohol.
tion with screen time and time devoted to vigorous or
moderate physical activity per week. The first model
Statistical analysis
was controlled for gender, urban or rural environment,
indigenous ethnicity, studying at present, tobacco use,
Analyses were adjusted according to the sampling
alcohol consumption, and physical activity classifica-
design of ENSANUT 2006 using the SVY module for
tion. The second model was control ed for the same
complex samples of STATA Version 9.2.*
variables except physical activity. A 0.05 level of signifi-

The analysis was carried out considering the de-
cance was used for all results.
pendent variable (BMI) as dichotomous (absence or
presence of overweight or obesity).
Results

Screen time was classified as acceptable, borderline
excessive, and excessive. Screen time was regarded as
There were 24 921 adolescent respondents to the physi-
acceptable if it was up to 7 hours but less than 14 hours
cal activity questionnaire. A BMI for 18 784 adolescents
per week (the equivalent of 1 to 2 hours per day). The
was obtained (9 582 females and 9 202 males). Seventy-
American Academy of Pediatrics recommends no more
one percent of the adolescents lived in an urban setting
than one to two hours per day.29 Screen time was con-
and 10% belonged to indigenous groups. A total of 38.0%
sidered borderline excessive if it was between 14 and
were of low socioeconomic status, 33.0% of medium and
21 hours per week (average 2 hours and 30 minutes per
29% of high socioeconomic status (Table I). Mean age
day), and excessive if it was over 21 hours per week
was 14.04±0.032 years and mean weight in adolescents
(three or more hours per day).
was 52.3±15.3 kg, with a mean height of 154.0±11.8 cm

Adolescents were classified according to the
and a mean BMI of 21.7±4.6. Table II shows means by
amount of time they practiced moderate and vigorous
age groups. Overal , overweight and obesity prevalences
physical activities as active, moderately active and
were 21.6% and 9.3%, respectively.
inactive. Adolescents who reported performing 7 or

A total of 23.6% (95% CI; 22.1, 25.3) of males and
more hours a week of moderate or vigorous physical
31.4% (95% CI; 29.6, 33.2) of females spent at least 7
activity were classified as active.30 Those reporting 4 to
hours per week on screen time and 23.3% (95% CI; 22.0-
24.6) of males and 28.7% (95% CI; 27.4-30.1) of females
spent between 7 and 13.9 hours per week on screen
time; for 19.1% (95% CI; 17.9,20.3) of female adolescents
screen time was between 14 to 20.9 hours and for 33.5%
* Stata Corp. Intercooled Stata 9.2 College Station Texas, USA, 2006.
(95% CI; 31.8,35.2) of males it was more than 21 hours
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Original article
Morales-Ruán MC et al.
Table I
the prevalence of overweight and obesity, after adjust-
Socio-demographic characteriSticS of mexican
ment for age, sex, studying at present, tobacco use,
adoleScentS aged 10 to 19 yearS. mexico,
alcohol consumption, urban or rural set ing, indigenous
enSanUt 2006
ethnicity, and physical activity (Table IV). Adolescents
from rural settings were less likely to be overweight or
Variable
Mean
SD
Age
14.04
0.032
obese when compared to those living in urban settings
n
N* (thousands)
%
(OR 0.63, 95% CI; 0.56, 0.72). Adolescents not attending
school were more prone to be overweight or obese when
Gender
compared to those who attended school.
Male
9 202
8 595.0
49.0

In the second logistic regression model (Table V),
Female
9 582
8 700.8
51.0
adolescents who were very active (screen time less than
7 hours per week and physical y active) were less likely
Setting
to be overweight or obese when compared to the al the
Urban
13 063
12 196.4
71.0
other adolescents together (OR 0.59, 95% CI; 0.48, 0.73).
Rural
5 721
5 099.5
29.0
Region
Discussion
North
4 243
3 091.7
17.9
Screen time was positively associated with overweight
Center
7 210
6 908.2
39.9
or obesity in a probabilistic sample of Mexican ado-
Mexico City
440
1 142.0
6.6
lescents. There was no association between intense or
South
6 891
6 153.9
35.6
moderate physical activity and overweight or obesity.
Furthermore, in the analysis with variables that consider
Socioeconomic level
screen time and time dedicated to physical activities, the
Low
7 113
6 616.6
38.0
categories with higher odds of obesity and overweight
Medium
6 588
5 770.8
33.0
were the ones that had high screen time, suggesting
High
5 083
4 908.5
29.0
a high relevance of this variable in the prevention of
obesity and overweight
Indigenous ethnicity

This finding is very important because it is the
Yes
1 831
1 804.9
10.0
first to document the time that adolescents performed
No
16 953
15 490.9
90.0
physical activity and screen time at the national level
in Mexican adolescents. In addition, this study can be a
Studying at present
basis for intervention programs to reduce screen time,
Yes
15 036
13 695.6
79.2
given the high prevalence of overweight and obesity in
No
3 748
3 600.3
20.8
adolescents in the country.
* N expanded to estimate the number of case in the population using the

The results of this study corroborate the findings of
sample weighting factors at national level
the Youth Risk Behavior Survey 1999,21 which also found
an association between TV viewing time and overweight
and a weak association between physical activity and a
reduction in BMI. In a European cross-sectional study31
researchers have also reported a positive association
per week, or the equivalent of over three hours every
between TV viewing time and overweight or obesity.
day; this percentage was lower for females (20.8%, 95%

Other studies with the objective of investigating
CI; 19.4, 22.3) (Table III).
the association of TV viewing and physical activity with

A total of 42.5% (95% CI; 40.8, 44.3) of females were
overweight in adolescents32 have found that adolescents
classified as passive, 24.6% (95% CI; 23.3, 26.0) as mod-
watching low levels of TV did not have increased odds
erately active and 32.9% (95% CI; 31.3, 34.5) as active.
of overweight, with the exception of females with low
This was dif erent from males, 36.6% of whom were
TV viewing and low physical activity (OR 1.48); females
classified as passive (95% CI; 35.0, 38.3), 25.1% (95%CI;
with high TV viewing and low physical activity had the
23.7, 26.5) as moderately active and 38.3% (95%CI; 36.7,
highest odds of overweight (OR 3.11).
40.0) as active (Table III).

One of the limits of this study was the lack of

Results from the first logistic regression model
information about food consumption practices during
showed that screen time was positively associated with
screen time. It is not possible to distinguish whether the
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Obesity and screen time in adolescents
Original article
Table II
anthropometric characteriSticS of adoleScentS. mexico, enSanUt 2006
Age groups
Female
Male
Both
Variable
n
N*( thousands) Median
SD
n
N* (thousands) Median
SD
n
N *( thousands) Median SD
Weight (kg)
10-13 years
4 437
3 950.0
43.9
11.7
4 519
4 031.3
44.1
13.58
8 956
7 981.3
44.0
12.7
14-16 years
2 733
2 586.1
55.6
12.0
2 769
2 728.5
59.6
13.62
5 502
5 314.6
57.7
13.0
17-19 years
2 412
2 164.7
58.2
13.2
1 914
1 835.3
66.3
14.13
4 326
4 000.0
61.9
14.2
Total
9 582
8 700.8
51.0
13.8
9 202
8 595.1
53.8
16.61 18 784
17 295.9
52.3
15.3
Height (cm)
10-13 years
4 437
3 950.0
146.4
9.3
4 519
4 031.3
146.9
11.39
8 956
7 981.3
146.6
10.4
14-16 years
2 733
2 586.1
155.2
6.8
2 769
2 728.5
164.0
8.09
5 502
5 314.6
159.7
8.7
17-19 years
2 412
2 164.7
155.8
6.7
1 914
1 835.3
167.3
7.86
4 326
4 000.0
161.0
9.3
Total
9 582
8 700.8
151.3
9.2
9 202
8 595.1
156.7
13.44 18 784
17 295.9
154.0
11.8
BMI (kg/m2)
10-13 years
4 437
3 950.0
20.3
4.0
4519
4 031.3
20.1
4.18
8 956
7 981.3
20.2
4.1
14-16 years
2 733
2 586.1
23.0
4.4
2769
2 728.5
22.0
4.18
5 502
5 314.6
22.5
4.3
17-19 years
2 412
2 164.7
23.9
4.9
1914
1 835.3
23.6
4.51
4 326
4 000.0
23.8
4.7
Total
9 582
8 700.8
22.0
4.6
9202
8 595.1
21.5
4.48 18 784
17 295.9
21.7
4.6
IOTF category
%
%
%
Normal
6 372
5 941.6
68.3
6 191
6 012.7
67.3
12 563
11 954.3
69.1
Overweight
2 293
1 975.0
22.7
1 994
1 764.6
21.7
4 287
3 739.7
21.6
Obese
917
784.1
9.0
1 017
817.8
11.0
1 934
1 601.9
9.3
* N expanded to estimate the number of cases in the population using the sample weighting factors at national level
IOTF: International Obesity Task Force
association between screen time, especial y TV viewing,
for the Mexican population, has been proven to be valid,
and overweight and obesity occurs due to a reduction
and yielded reproducible results for screen time and
of physical activity or an increase in energy consump-
moderate and vigorous activity measurements.26
tion at ributable to snacking while watching TV. Studies

The instrument used to assess physical activity or
have found evidence that food consumption increases
screen time, although validated in the Mexican popu-
during the time spent watching TV.33-35 This limitation,
lation, may have non-random measurement errors
however, does not invalidate the association between
that could attenuate the association between physical
screen time and being overweight and obese, since the
activity and screen time with obesity. Therefore, the
study controlled for physical activity.
estimates presented may be conservative and the as-

The cross-sectional design does not distinguish the
sociations may be stronger than the ones documented
direction of the association; it is possible that excess body
in this paper.
weight causes reduced physical activity and sedentary

The strength of this study lies in its design, which
behavior.
is probabilistic and includes a national representative

Another possible limitation is the instrument used
sample. However, since this was a cross-sectional study,
to measure screen time and physical activity. The instru-
it was not possible to determine a cause-effect relation
ment is based on reports from the adolescents and not
between screen time and overweight and obesity in
on direct observation or the use of an accelerometer.
adolescents. Other longitudinal studies corroborate a
Nevertheless, this instrument that has been validated
similar relationship.36 Randomized trials in which the
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Original article
Morales-Ruán MC et al.
Table III
claSSification of adoleScentS according to Screen time and phySical activity, by age groUpS.
mexico, enSanUt 2006


Screen time (hours per week)






< 7 h‡

≥ 7 < 14 h‡

≥ 14 < 21 h

≥ 21 h


n
N* (thousands)
%
95% CI
%
95% CI
%
95% CI

95% CI
Women










10-13 years
4 437
3 950.0
32.8
(30.5 , 35.2 )
28.1
(26.1 , 30.3 )
18.9
(17.2 , 20.8 )
20.1 (18.2 , 22.1 )
14-16 years
2 733
2 586.1
28.2
(25.7 , 30.8 )
30.8
(28.4 , 33.2 )
19.9
(17.9 , 22.1 )
21.2 (19.0 , 23.6 )
17-19 years
2 412
2 164.7
32.5
(29.5 , 35.7 )
27.2
(24.6 , 30.0 )
18.5
(16.4 , 20.8 )
21.8 (19.0 , 24.8 )
Total
9 582
8 700.8
31.4
(29.6 , 33.2 )
28.7
(27.4 , 30.1 )
19.1
(17.9 , 20.3 )
20.8 (19.4 , 22.3 )
Men






10-13 years
4 519
4 031.3
23.5
(21.4 , 25.6 )
23.9
(22.0 , 25.8 )
19.8
(18.1 , 21.6 )
32.9 (30.6 , 35.3 )
14-16 years
2 769
2 728.5
24.5
(22.1 , 27.1 )
21.0
(18.9 , 23.3 )
19.4
(17.3 , 21.7 )
35.1 (32.3 , 37.9 )
17-19 years
1 914
1 835.3
22.6
(19.7 , 25.8 )
25.4
(22.5 , 28.6 )
19.4
(16.9 , 22.1 )
32.5 (29.4 , 35.9 )
Total
9 202
8 595.0
23.6
(22.1 , 25.3 )
23.3
(22.0 , 24.6 )
19.6
(18.3 , 20.9 )
33.5 (31.8 , 35.2 )


Physical activity (hours per week)

Moderately



Passive
(< 4 h)
Active (≥4 <

Active (≥7 h)§



7 h)
Women









10-13 years
4 437
3 950.0
43.0
(40.6 , 45.4 )
27.0
(25.0 , 29.1 )
30.0
(28.1 , 32.1 )


14-16 years
2 733
2 586.1
39.8
(37.1 , 42.7 )
24.9
(22.7 , 27.2 )
35.3
(32.6 , 38.1 )


17-19 years
2 412
2 164.7
44.9
(41.9 , 47.9 )
19.9
(17.6 , 22.5 )
35.2
(32.2 , 38.3 )


Total
9 582
8 700.8
42.5
(40.8 , 44.3 )
24.6
(23.3 , 26.0 )
32.9
(31.3 , 34.5 )


Men







10-13 years
4 519
4 031.3
37.1
(34.9 , 39.3 )
24.4
(22.7 , 26.3 )
38.5
(36.2 , 40.8 )


14-16 years
2 769
2 728.5
35.4
(32.7 , 38.2 )
26.7
(24.2 , 29.4 )
37.9
(35.0 , 40.8 )


17-19 years
1 914
1 835.3
37.3
(34.0 , 40.7 )
24.0
(21.0 , 27.2 )
38.7
(35.5 , 42.1 )


Total
9 202
8 595.0
36.6
(35.0 , 38.3 )
25.1
(23.7 , 26.5 )
38.3
(36.7 , 40.0 )


* N expanded to estimate the number of cases in the population using the sample weighting factors at national level
‡ Time recommended by the American Academy of Pediatrics (1 to 2 hours per day)29
§ Recommended physical activity time30
intervention was a reduction in TV viewing time have

This recommendation is important and applicable
found a reduction in obesity.37,38
to the adolescent population in Mexico, given the high

In the US and UK, there is consensus that children
prevalence of adolescents who are inactive and the
should have at least 60 minutes of moderate to vigor-
inadequate prevalence of screen time.
ous physical activity daily.39,40 In Canada, public health

Obesity prevalence among adolescents in Mexico
policies recommend not only increasing moderate and
and lack of physical activity indicate the need to promote
intense physical activity but also reducing sedentary
intense physical activity and to reduce sedentary activity
activity.
such as TV viewing and videogame playing.
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Obesity and screen time in adolescents
Original article
Table IV
logiStic regreSSion model for overweight and
References
obeSity related to Screen time in adoleScentS.
mexico, enSanUt 2006
1. Organización Mundial de la Salud. Obesidad y sobrepeso. Descriptive
note 311. September 2006. [Consulted 2007 March 13]. Available at:
Adjusted
www.who.int.
Variables
Crude OR
95% CI
95% CI
OR*
2. Lobstein T, Baur L, Uauy R, IASO. International Obesity Task Force.
Obesity in children and young people: a crisis in public health. Obes Rev
Screen time (hours per week)
2004;5 (suppl 1):4-104.
< 7 hours
1
1
≥
3. Olaiz-Fernández G, Rivera-Dommarco J, Shamah-Levy T, Rojas R,
7 hours to < 14 hours
1.32 (1.16 , 1.51)
1.20 (1.05 , 1.36)
≥
Villalpando-Hernández S, Hernández-Ávila M, et al. Encuesta Nacional de
14 hours to < 21 hours
1.32 (1.14 , 1.53)
1.18 (1.02 , 1.36)
≥
Salud y Nutrición 2006. Cuernavaca, México: Instituto Nacional de Salud
21 hours
1.51 (1.32 , 1.72)
1.29 (1.13 , 1.48)
Pública, 2006.
Female
1
1
4. Stark O, Atkins E, Wolff OH, Douglas JWB. Longitudinal study of
Male
0.88 (0.80 , 0.97)
0.90 (0.82 , 0.99)
obesity in the National Survey of Health and Development. Br Med J
Age (in years)
1.01 (0.99 , 1.02)
0.99 (0.97 , 1.01)
1981;283:12-17.
Studying at present (yes)
1
1
5. Freedman D, Kettel L, Serdula M, Dietz W, Srinivasan S, Berenson G. The
Studying at present (no)
1.13 (1.00 , 1.27)
1.14 (1.00 , 1.29)
relation of childhood BMI to adult adiposity: the Bogalusa Heart Study.
Tobacco use (no)
1
1
Pediatrics 2005;115:22-27.
Tobacco use (yes)
1.04 ( 0.92 , 1.17)
0.94 (0.83 , 1.07)
6. Must A, Jacques PF, Dallal GE, Bajema CJ, Dietz WH. Long-term morbidity
Alcohol consumption (no)
1
1
and mortality of overweight adolescents: a follow-up of the Harvard
Alcohol consumption (yes)
1.15 (0.99 , 1.33)
1.12 (0.95 , 1.32)
Growth Study of 1922 to 1935. N Engl J Med 1992;327:1350-1355.
Urban setting
1
1
7. Dietz W. J. Childhood weight affects adult morbidity and Mortality. J
Rural setting
0.63 (0.56 , 0.72)
0.66 (0.58 , 0.75)
Nutr 1998;128: 411S-414S.
Indigenous ethnicity (no)
1
1
8. Dietz W. Health consequences of obesity in youth: childhood predictors
Indigenous ethnicity (yes)
0.62 (0.52 , 0.75)
0.69 (0.58 , 0.82)
of adult disease. Pediatrics 1998;101;518-525.
9. Erickson SJ, Robinson TN, Haydel KF, Killen JD. Are overweight children
Physical activity (hours per week)
unhappy? Body mass index, depressive symptoms, and overweight
Inactive (< 4 hours)
1
1
concerns in elementary school children. Arch Pediatr Adolesc Med
Moderately Active (≥4 < 7 hours)
0.99 (0.88 , 1.10)
0.96 (0.86 , 1.08)
2000;154:931-935.
Active (≥7 hours)
0.92 (0.83 , 1.01)
0.93 (0.83 , 1.03)
10. Xie B, Chou CP, Spurjit-Metz D, Liu C, Xia J, Gong J, et al. Effects of
* Adjust for gender, urban o rural setting, and indigenous ethnicity, studying
perceived peer isolation and social support availability on the relationship
at present, tobacco use, alcohol consumption and physical activity
between body mass index and depressive symptoms. Int J Obes (Lond)
2005;29(9):1137-1143.
Table V
logiStic regreSSion model for overweight and obeSity and their aSSociation to Screen time
and doing phySical activity in adoleScentS. mexico, enSanUt 2006
Variables
Crude OR
95% CI
Adjusted OR*
95% CI
Categories by screen time and time performing physical activity (hours per week)
Very passive (≥ 21 screen time hours, <4 physical activity hours)
1
1
Moderately passive (< 7 screen time hours, <4 physical activity hours)
0.69
(0.56 , 0.85)
0.79
(0.64 , 0.98)
Slightly active (≥ 21screen time hours, ≥ 7 physical activity hours)
0.93
(0.75 , 1.14)
0.95
(0.77 , 1.17)
Very active (< 7 screen time hours, ≥ 7 physical activity hours)
0.59
(0.48 , 0.73)
0.70
(0.57 , 0.88)
Female
1
1
Male
0.82
(0.71 , 0.95)
0.85
(0.73 , 0.98)
Age
1.00
(0.97 , 1.02)
0.98
(0.95 , 1.01)
Studying at present (yes)
1
1
Studying at present (no)
1.13
(0.95 , 1.35)
1.18
(0.98 , 1.43)
Tobacco use (no)
1
1
Tobacco use (yes)
0.84
(0.70 , 1.01)
0.74
(0.61 , 0.91)
Alcohol consumption (no)
1
1
Alcohol consumption (yes)
1.21
(0.96 , 1.52)
1.32
(1.02 , 1.72)
Urban setting
1
1
Rural setting
0.64
(0.53 , 0.78)
0.68
(0.56 , 0.83)
Indigenous ethnicity (no)
1
1
Indigenous ethnicity (yes)
0.52
(0.41 , 0.67)
0.59
(0.45 , 0.76)
* Adjust for gender, urban o rural setting, indigenous ethnicity, studying at present, tobacco use and alcohol consumption
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Original article
Morales-Ruán MC et al.
11. Needhham BL, Crosnoe R. Overweight status and depressive
26. Hernández B, Gortmarker S, Larid N, Colditz G, Parra-Cabrera,
symptoms during adolescence. J Adolesc Health 2005;36(1):48-55.
Peterson K. Validez y reproducibilidad de un cuestionario de actividad e
12. WHO/FAO. Diet, nutrition and the prevention of chronic diseases.
inactividad física para escolares de la ciudad de México. Salud Publica Mex
Report of a Joint WHO/FAO Expert Consultation. World Health Organ
2000;42:315-323.
Tech Rep Ser 2003;916:i–viii, 1-149.
27. Ainsworth BE, Haskell WL, Whitt MC, Irwin ML, Swartz AM, Strath SJ,
13. Quatromoni PA, Copenhafer DL, D’Agostino RB, Millen BE. Dietary
et al. Compendium of physical activities. Med Sci Sports Exerc 2000;32(9
patterns predict the development of overweight in women: The
Suppl):S498-S504.
Framingham Nutrition Studies. J Am Diet Assoc 2002;102:1239-1246.
28. Resano E, Méndez I, Shamah T, Rivera J, Sepúlveda J. Methods of
14. Schulz M, Nothlings U, Hoffmann K, Bergmann MM, Boeing H.
the National Nutrition Survey 1999. Salud Publica Mex 2003:45 Suppl
Identification of a food pattern characterized by high-fiber and low-fat
4:S558-S564.
food choices associated with low prospective weight change in the
29. American Academy of Pediatrics. Committee on Public Education
EPICPotsdam cohort. J Nutr 2005;135:1183-1189.
Pediatrics. Pediatrics 2001;108:1222-1225.
15. US Department of Health and Human Services. Physical activity and
30. Council on Sports Medicine and Fitness and Council on School
health: a report of the surgeon general. Atlanta (GA): US Department of
Health. Active Healthy Living: Prevention of Childhood Obesity Through
Health and Human Services, Center for Chronic Diseases Prevention and
Increased Physical Activity. Pediatrics 2006;117:1834-1842.
Health Promotion, 1996.
31. Velde S, De Bourdeaudhuij I,Thorsdottir I, Rasmussen M, Hagströmer
16. Maffeis C, Talamini G, Tatò L. Influence of diet, physical activity and
M, Klepp KI, et al. Patterns in sedentary and exercise behaviors and
parent’s obesity on children’s adiposity: a four year longitudinal study. Int J
associations with overweight in 9-14-year-old boys and girls –a cross-
Obes Relat Metab Disord 1998;22:758-764.
sectional study. BMC Public Health 2007;31:7-16.
17. Crespo CJ, Smit E, Trojano RP, Barlet SJ, MaceraCA, Andersen RE.
32. Eisenmann JC, Bartee RT, Smith DT, Welk GJ, Fu Q. Combined
Television watching, energy intake, and obesity in US children: results from
influence of physical activity and television viewing on the risk of
the third National Health and Nutrition Examination Survey, 1988-1994.
overweight in US youth. Int J Obes 2008;32:613-618.
Arch Pediatr Adolesc Med 2001;155(3):360-365.
33. Cleland VJ, Schmidt MD, Dwyer T, Venn AJ. Television viewing and
18. Dietz WH. Physical activity and childhood obesity. Nutrition
abdominal obesity in young adults: is the association mediated by food
1991;7:295-297.
and beverage consumption during viewing time or reduced leisure-time
19. Gortmaker S, Must A, Sobol A, Peterson K, Colditz G, Dietz W.
physical activity? Am J Clin Nutr 2008;87(5):1148-1155.
Television viewing as a cause of increasing obesity among children in the
34. Coon KA, Goldberg J, Rogers BL, Tucker KL. Relationships between
United States, 1986-1990. Arch Pediatr Adolesc Med 1996;150:356-362.
use of television during meals and children’s food consumption patterns.
20. Dietz WH, Gortmaker SL. Do we fatten our children at the television
Pediatrics 2001;107:E7.
set? Obesity and television viewing in children and adolescents. Pediatrics
35. Stroebele N, de Castro JM. Television viewing is associated with an
1985;75:807-812.
increase in meal frequency in humans. Appetite 2004;42:111-113.
21. Einsenmann J, Bartee T, WANG Q. Physical Activity, TV viewing,
36. Xu F, Li J, Ware RS, Owen N. Associations of television viewing time
and weight in US youth: 1999 Youth Risk Behavior Survey. Obes Res
with excess body weight among urban and rural high-school students in
2002;10:379-385.
regional mainland China. Public Health Nutr 2008;11(9):891-896.
22. Hernandez B, Gortmaker SL, Colditz GA, Peterson KE, Laird NM,
37. Robinson TN. Reducing children’s television viewing to prevent
Parra-Cabrera S. Association of obesity with physical activity, television
obesity: a randomized controlled trial. JAMA 1999;282:1561-1567.
programs and other forms of video viewing among children in Mexico
38. Gortmaker SL, Peterson K, Wiecha J, Sobol AM, Dixit S, Fox MK, et al .
City. Int J Obes 1999;23:845-854.
Reducing obesity via a school-based interdisciplinary intervention among
23. Palma O Shamah-Levy T, Franco A, Olaiz G, Méndez-Ramírez I.
youth: Planet Health. Arch Pediatr Adolesc Med 1999;153:409-418.
Metodología. In: Olaiz-Fernández G, Rivera-Dommarco J, Shamah-Levy
39. Biddle S, Sallis J, Cavill N. Policy framework for young people and
T, Rojas R, Villalpando-Hernández S, Hernández-Avila M, et al. Encuesta
health-enhancing physical activity. In: Biddle S, Sallis J, Cavill N, Ed. Young
Nacional de Salud y Nutrición 2006. Cuernavaca, México: Instituto
and active: young people and physical activity. London, England: Health
Nacional de Salud Pública, 2006: 19-33.
Education Authority, 1998: 3-16.
24. Habitch JP. Estandarización de métodos epidemiológicos cuantitativos
40. Strong WB, Malina RM, Blimkie CJ, Daniels SR, Dishman RK, Gutin
sobre el terreno. (Standardization of anthropometric methods in the
B, et al. Evidence based physical activity for school-age youth. J Pediatr
field.) PAHO Bull 1974;76:375-384.
2005;146:732-737.
25. Cole T, Bellizi M. Establishing a standard definition for child overweight
and obesity worldwide: international survey. BMJ 2000;320:1-6.
S620
salud pública de méxico / vol. 51, suplemento 4 de 2009

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