Research in Developmental Disabilities 36 (2015) 428–436
Contents lists available at ScienceDirect
Research in Developmental Disabilities
Associations of physical activity with fatness and fitness in adolescents with Down syndrome: The UP&DOWN study Rocı´o Izquierdo-Gomez a,*, David Martı´nez-Go´mez a, Ariel Villagra a, ´ scar L. Veiga a on behalf of the UP&DOWN study group1 Bo Fernhall b, O a b
Department of Physical Education, Sport and Human Movement, Autonomous University of Madrid, Madrid, Spain Department of Kinesiology and Nutrition, University of Illinois, Chicago, IL, USA
A R T I C L E I N F O
A B S T R A C T
Article history: Received 7 October 2014 Received in revised form 12 October 2014 Accepted 15 October 2014 Available online 8 November 2014
The aim of the present study was to examine the associations of objectively measured physical activity (PA) with several markers of fatness and fitness in a relatively large sample of adolescents with Down syndrome (DS). This study comprised a total of 100 adolescents with DS (37 females) aged 11–20 years-old, and a sex-matched sample of 100 adolescents without disabilities, participating in the UP&DOWN study. The ALPHA healthrelated fitness test battery for adolescents was used to assess fatness and fitness. PA was measured by accelerometry. Adolescents with DS had higher fatness and significantly lower fitness levels in all variables measured than adolescents without DS (all p < 0.05). Moderate-to-large effects were observed in fatness variables (d = 0.65–1.42), but particularly large values were found in fitness variables (d = 2.05–2.43). In addition, PA levels was not associated with fatness variables, whereas total PA and vigorous PA were associated with all fitness variables (p < 0.05), and moderate-vigorous PA (MVPA) was associated with muscular fitness (p < 0.05), after adjusting for potential confounders. Further analysis revealed that there were differences in fitness by tertiles of vigorous PA between the lowest and the highest groups in all fitness variables (all p < 0.05). However, no significant differences were found in fitness by tertiles of MVPA according with PA guidelines (60 min in MVPA). Our findings indicate that PA levels are not associated with fatness variables, whereas high PA levels, in particular vigorous PA, are positively associated with high fitness in adolescents with DS. ß 2014 Elsevier Ltd. All rights reserved.
Keywords: Obesity Physical fitness Physical activity Adolescents Down syndrome
1. Introduction Obesity is considered a worldwide health problem in adolescence (WHO, 2004). Also, low levels of fitness have a detrimental effect on health (Ortega, Ruiz, Castillo, & Sjo¨stro¨m, 2008; Ruiz et al., 2009). Physical activity (PA) is a lifestyle factor with an important role on health across the lifespan (Physical Activity Guidelines Advisory Committee, 2008). In adolescence, several studies have reported that high levels of PA might have a beneficial impact in both fatness (Ortega, Ruiz, & Castillo, 2013) and fitness (Martinez-Gomez et al., 2011; Martinez-Gomez et al., 2010; Moliner-Urdiales et al., 2010; Ruiz
* Corresponding author at: Departamento de Educacio´n Fı´sica, Deporte y Motricidad Humana, Universidad Auto´noma de Madrid, Ctra. de Colmenar Km. 15, CP. 28049, Madrid, Spain. Tel.: +34 91 497 21 15; fax: +34 91 497 84 80. E-mail address: [email protected] (R. Izquierdo-Gomez). 1 See Appendix A. http://dx.doi.org/10.1016/j.ridd.2014.10.022 0891-4222/ß 2014 Elsevier Ltd. All rights reserved.
R. Izquierdo-Gomez et al. / Research in Developmental Disabilities 36 (2015) 428–436
429
et al., 2006). However, this has been shown in the general population and little is known regarding population with disabilities. Down syndrome (DS) is a chromosomal disorder with an estimated incidence of 1 in 1000 live births (Roizen & Patterson, 2003). Individuals with DS exhibit more than 80 clinical characteristics (e.g. congenital heart defects, muscle hypotonicity, etc.) that may influence body fat and levels of fitness (Bull & Committee on Genetics, 2011). In fact, youth with DS continue to exhibit higher obesity and lower levels of fitness compared with their counterpart without disabilities, even those with intellectual disabilities without DS (Pitteti, Baynard, & Agiovlasitis, 2013). There are different methods of assessing PA in free-living conditions in adolescence (Ortega et al., 2013). In general, subjective PA measures obtained from questionnaires have poor accurate compared with objective measures, especially in adolescents with intellectual disabilities (Cervantes & Porretta, 2010). Thus, objective measurements of PA, such as accelerometry, are preferred in this population. To date, most of the studies exploring the association of objectively measured PA with fatness and fitness in adolescents with DS are limited to single indicators of fatness (i.e. body mass index [BMI]) and fitness (i.e. cardiorespiratory fitness) (Esposito, MacDonald, Hornyak, & Ulrich, 2012; Matute-Llorente, Gonza´lezAgu¨ero, Go´mez-Cabello, Vicente-Rodrı´guez, & Casaju´s, 2013; Nordstrøm, Hansen, Paus, & Kolset, 2013; Shields, Dodd, & Abblitt, 2009), when other indicators of these outcomes may be equally or more relevant for this population. Therefore, the aim of the present study was to examine the association of objectively measured PA with several markers of fatness (i.e. body mass index, waist circumference and percentage of body fat) and fitness (i.e. motor fitness, muscular fitness and cardiorespiratory fitness) in a relatively large sample of adolescents with DS. 2. Methods 2.1. Participants Participants included for this study were enrolled in the UP&DOWN study (Follow UP school children AND in adolescents with DOWN syndrome: psycho-environmental and genetic determinants of PA and its impact on fitness, cardiovascular ˜ ero et al., 2014). For the purpose of this cross-sectional diseases, inflammatory biomarkers and mental health) (Castro-Pin study, we had baseline data of a total of 100 adolescents with DS (37 females) aged 11–20 years-old, recruited from special education schools, associations and foundations for people with intellectual disabilities from the regions of Madrid and Toledo (Spain). In addition, we selected a sex-matched sample of 100 participants (1:1) from adolescent without disabilities ˜ ero et al., 2014) to confirm whether our sample of adolescents with DS was cohort belong to the UP&DOWN study (Castro-Pin at risk for obesity and low levels of fitness, recruited from high-schools in Madrid (Spain). All participants with DS met two specific inclusion criteria: having an intelligence quotient over 35 and not having any physical disabilities impacting PA. Data were collected from October 2011 to December 2012. Parents, adolescents and institution supervisors were informed about the study characteristics, and then they were asked to sign an informed consent form before participation. The study protocols were approved by the Ethics Committee of the Hospital Puerta de Hierro (Madrid, Spain) and the Bioethics Committee of the National Research Council (Madrid, Spain). 2.2. Measurements Body fat. Weight and height were measured with participants without shoes and wearing lightweight clothing. Weight was recorded to the nearest 0.1 kg using an electronic scale (model SECA 701, Hamburg, Germany) and height was measured to the nearest 1 mm using a telescopic height-measuring instrument (model SECA 220). BMI was calculated as weight in kilograms divided by height in metres squared (kg/m2). Skinfold thickness was measured on the non-dominant side of the body to the nearest 0.1 mm with a Holtain calliper at the triceps and subscapular sites. Body fat percentage (BF%) was calculated from triceps and subscapular skinfold thicknesses using the Slaughter equations (Slaughter et al., 1988). Waist circumference (indicator of abdominal body fat) was measured with a non-elastic tape (SECA 200; SSECA, Hamburg, Germany) to the nearest 0.1 cm. Anthropometric measures were performed twice and the average was recorded (TejeroGonzalez et al., 2013). Physical fitness. Fitness was examined using the Assessing Level of Physical Activity (ALPHA) and health-related fitness test battery for youth (Castro-Pinero et al., 2010; Ruiz et al., 2011). Reliability of the ALPHA health-related fitness test was good in adolescents with DS with some adaptations, which have been reported elsewhere (Tejero-Gonzalez et al., 2013). All assessments were conducted with one or two instructors to guide and help the adolescents when necessary. Muscular fitness was measured using the handgrip strength and the standing long jump test (lower limb explosive strength). To assess handgrip strength, a hand dynamometer with an adjustable grip (TKK 5101 Grip D, Takey, Tokyo Japan) was used. The adolescents with DS squeezed the dynamometer gradually and continuously for at least 2-s in sitting position, performing the test with both hands and with the elbow in full extension (Tejero-Gonzalez et al., 2013). The test was completed twice and the maximum score in kilograms for each hand was recorded, and the average score of the left and right hand was calculated. To assess lower limb explosive strength, adolescent had to jump as far as possible from a starting position behind a line standing with feet approximately shoulder’s width apart. The test was completed twice and the longer distance was recorded in centimetres (Ortega, Artero, et al., 2008). A single muscular fitness score was calculated from the two muscular tests. A final muscular fitness score was estimated as the mean of the two standardized scores
430
R. Izquierdo-Gomez et al. / Research in Developmental Disabilities 36 (2015) 428–436
(Martinez-Gomez et al., 2011). The individual score of each test was standardized as follows: Z-standardized value = (value-mean)/SD. Motor fitness was measured using the 4 10 m shuttle-run test of speed-of-movement, agility and coordination. The adolescent was required to run between two parallel lines 10-m apart. They run as fast as possible from the starting line to the other line and they should pick up (the first time) or exchange (second and third time) a sponge that has earlier been placed behind the lines. The test was performed twice and the fastest time was recorded in seconds (Ortega, Artero, et al., 2008). Since the lower the score, the better the performance, it was multiplied by 1. Hence, a higher score indicates a better motor fitness. Cardiorespiratory fitness was measured using the 20-m shuttle-run test. The adolescents were required to run between two lines 20-m apart, while keeping pace with a pre-recorded audio CD. The initial speed was 8.5 km/h, which was increased by 0.5 km/h each minute (1 min equals one stage). The adolescents were instructed to run in a straight line, to pivot on completing a shuttle (20-m), and to pace themselves in accordance with the audio signals. The test was finished when the adolescent failed to reach the end lines concurrent with the audio signals on two consecutive occasions. The score for adolescents with DS was the number of laps completed (Ortega, Artero, et al., 2008). Physical activity. The Actigraph accelerometer, models GT1M, GT3X and GT3X+ (ActigraphTM, Pensacola, FL, USA), were used to direct measure objectively PA. This accelerometer has been widely validated in laboratory settings and free-living conditions with children and adolescents without disabilities (Freedson, Pober, & Janz, 2005). Recent studies have showed that there is strong agreement among the three models (Robusto & Trost, 2013; Vanhelst et al., 2012). Adolescents were instructed to wear the accelerometer for 7 consecutives days at the lower back fitted with an elastic belt, excepted during sleep hours and water-based activities. The Freedson’s age-specific cut-points were used to estimate intensities of total PA, moderate PA and vigorous PA (Freedson et al., 2005). Variables obtained by the ActiGraph accelerometer were analyzed as counts per minute (cpm) for total PA and min/day for levels of PA. The time spent in moderate-vigorous PA (MVPA) was computed by summing the time in moderate and vigorous PA intensities (min/day). This score was also dichotomized into two categories ( 0.05) (Fig. 1).
Table 2 Differences in levels of fatness and fitness among adolescents with or without Down syndrome.
Age (years) Weight (kg) Height (cm) Body mass index (kg/m2) Body fat (%) Waist circumference (cm) Muscular fitness (Z-score) Motor fitness (sec 1) Cardiorespiratory fitness (laps)
Down syndrome
Non-Down syndrome
n
n
100 100 100 100 100 100 97 98 98
15.43 2.54 52.61 12.25 148.20 9.56 23.78 3.96 34.88 12.76 73.36 9.42 0.66 0.58 19.22 4.49 8.21 5.96
100 100 100 100 100 100 100 100 100
13.57 1.74 54.98 11.42 161.76 11.29 20.85 2.90 19.61 8.36 68.20 6.23 0.66 0.70 11.91 1.13 50.54 23.84
DS vs. non DS Mean difference (95% CI)
1.86 2.38 13.58 2.93 15.27 5.16 1.31 7.31 42.32
(1.25 to 2.5) ( 5.66 to 0.91) ( 16.48 to 10.65) (1.98 to 3.90) (12.26 to 18.28) (2.93 to 7.38) ( 1.50 to 1.14) (6.40 to 8.22) ( 47.22 to 37.43)
Statically significant are showed in bold. Values are mean SD. P1, unadjusted; P2, age-adjusted.
Cohen’s d
P1
P2
0.85 0.20 1.30 0.84 1.42 0.65 2.05 2.24 2.43
Contents lists available at ScienceDirect
Research in Developmental Disabilities
Associations of physical activity with fatness and fitness in adolescents with Down syndrome: The UP&DOWN study Rocı´o Izquierdo-Gomez a,*, David Martı´nez-Go´mez a, Ariel Villagra a, ´ scar L. Veiga a on behalf of the UP&DOWN study group1 Bo Fernhall b, O a b
Department of Physical Education, Sport and Human Movement, Autonomous University of Madrid, Madrid, Spain Department of Kinesiology and Nutrition, University of Illinois, Chicago, IL, USA
A R T I C L E I N F O
A B S T R A C T
Article history: Received 7 October 2014 Received in revised form 12 October 2014 Accepted 15 October 2014 Available online 8 November 2014
The aim of the present study was to examine the associations of objectively measured physical activity (PA) with several markers of fatness and fitness in a relatively large sample of adolescents with Down syndrome (DS). This study comprised a total of 100 adolescents with DS (37 females) aged 11–20 years-old, and a sex-matched sample of 100 adolescents without disabilities, participating in the UP&DOWN study. The ALPHA healthrelated fitness test battery for adolescents was used to assess fatness and fitness. PA was measured by accelerometry. Adolescents with DS had higher fatness and significantly lower fitness levels in all variables measured than adolescents without DS (all p < 0.05). Moderate-to-large effects were observed in fatness variables (d = 0.65–1.42), but particularly large values were found in fitness variables (d = 2.05–2.43). In addition, PA levels was not associated with fatness variables, whereas total PA and vigorous PA were associated with all fitness variables (p < 0.05), and moderate-vigorous PA (MVPA) was associated with muscular fitness (p < 0.05), after adjusting for potential confounders. Further analysis revealed that there were differences in fitness by tertiles of vigorous PA between the lowest and the highest groups in all fitness variables (all p < 0.05). However, no significant differences were found in fitness by tertiles of MVPA according with PA guidelines (60 min in MVPA). Our findings indicate that PA levels are not associated with fatness variables, whereas high PA levels, in particular vigorous PA, are positively associated with high fitness in adolescents with DS. ß 2014 Elsevier Ltd. All rights reserved.
Keywords: Obesity Physical fitness Physical activity Adolescents Down syndrome
1. Introduction Obesity is considered a worldwide health problem in adolescence (WHO, 2004). Also, low levels of fitness have a detrimental effect on health (Ortega, Ruiz, Castillo, & Sjo¨stro¨m, 2008; Ruiz et al., 2009). Physical activity (PA) is a lifestyle factor with an important role on health across the lifespan (Physical Activity Guidelines Advisory Committee, 2008). In adolescence, several studies have reported that high levels of PA might have a beneficial impact in both fatness (Ortega, Ruiz, & Castillo, 2013) and fitness (Martinez-Gomez et al., 2011; Martinez-Gomez et al., 2010; Moliner-Urdiales et al., 2010; Ruiz
* Corresponding author at: Departamento de Educacio´n Fı´sica, Deporte y Motricidad Humana, Universidad Auto´noma de Madrid, Ctra. de Colmenar Km. 15, CP. 28049, Madrid, Spain. Tel.: +34 91 497 21 15; fax: +34 91 497 84 80. E-mail address: [email protected] (R. Izquierdo-Gomez). 1 See Appendix A. http://dx.doi.org/10.1016/j.ridd.2014.10.022 0891-4222/ß 2014 Elsevier Ltd. All rights reserved.
R. Izquierdo-Gomez et al. / Research in Developmental Disabilities 36 (2015) 428–436
429
et al., 2006). However, this has been shown in the general population and little is known regarding population with disabilities. Down syndrome (DS) is a chromosomal disorder with an estimated incidence of 1 in 1000 live births (Roizen & Patterson, 2003). Individuals with DS exhibit more than 80 clinical characteristics (e.g. congenital heart defects, muscle hypotonicity, etc.) that may influence body fat and levels of fitness (Bull & Committee on Genetics, 2011). In fact, youth with DS continue to exhibit higher obesity and lower levels of fitness compared with their counterpart without disabilities, even those with intellectual disabilities without DS (Pitteti, Baynard, & Agiovlasitis, 2013). There are different methods of assessing PA in free-living conditions in adolescence (Ortega et al., 2013). In general, subjective PA measures obtained from questionnaires have poor accurate compared with objective measures, especially in adolescents with intellectual disabilities (Cervantes & Porretta, 2010). Thus, objective measurements of PA, such as accelerometry, are preferred in this population. To date, most of the studies exploring the association of objectively measured PA with fatness and fitness in adolescents with DS are limited to single indicators of fatness (i.e. body mass index [BMI]) and fitness (i.e. cardiorespiratory fitness) (Esposito, MacDonald, Hornyak, & Ulrich, 2012; Matute-Llorente, Gonza´lezAgu¨ero, Go´mez-Cabello, Vicente-Rodrı´guez, & Casaju´s, 2013; Nordstrøm, Hansen, Paus, & Kolset, 2013; Shields, Dodd, & Abblitt, 2009), when other indicators of these outcomes may be equally or more relevant for this population. Therefore, the aim of the present study was to examine the association of objectively measured PA with several markers of fatness (i.e. body mass index, waist circumference and percentage of body fat) and fitness (i.e. motor fitness, muscular fitness and cardiorespiratory fitness) in a relatively large sample of adolescents with DS. 2. Methods 2.1. Participants Participants included for this study were enrolled in the UP&DOWN study (Follow UP school children AND in adolescents with DOWN syndrome: psycho-environmental and genetic determinants of PA and its impact on fitness, cardiovascular ˜ ero et al., 2014). For the purpose of this cross-sectional diseases, inflammatory biomarkers and mental health) (Castro-Pin study, we had baseline data of a total of 100 adolescents with DS (37 females) aged 11–20 years-old, recruited from special education schools, associations and foundations for people with intellectual disabilities from the regions of Madrid and Toledo (Spain). In addition, we selected a sex-matched sample of 100 participants (1:1) from adolescent without disabilities ˜ ero et al., 2014) to confirm whether our sample of adolescents with DS was cohort belong to the UP&DOWN study (Castro-Pin at risk for obesity and low levels of fitness, recruited from high-schools in Madrid (Spain). All participants with DS met two specific inclusion criteria: having an intelligence quotient over 35 and not having any physical disabilities impacting PA. Data were collected from October 2011 to December 2012. Parents, adolescents and institution supervisors were informed about the study characteristics, and then they were asked to sign an informed consent form before participation. The study protocols were approved by the Ethics Committee of the Hospital Puerta de Hierro (Madrid, Spain) and the Bioethics Committee of the National Research Council (Madrid, Spain). 2.2. Measurements Body fat. Weight and height were measured with participants without shoes and wearing lightweight clothing. Weight was recorded to the nearest 0.1 kg using an electronic scale (model SECA 701, Hamburg, Germany) and height was measured to the nearest 1 mm using a telescopic height-measuring instrument (model SECA 220). BMI was calculated as weight in kilograms divided by height in metres squared (kg/m2). Skinfold thickness was measured on the non-dominant side of the body to the nearest 0.1 mm with a Holtain calliper at the triceps and subscapular sites. Body fat percentage (BF%) was calculated from triceps and subscapular skinfold thicknesses using the Slaughter equations (Slaughter et al., 1988). Waist circumference (indicator of abdominal body fat) was measured with a non-elastic tape (SECA 200; SSECA, Hamburg, Germany) to the nearest 0.1 cm. Anthropometric measures were performed twice and the average was recorded (TejeroGonzalez et al., 2013). Physical fitness. Fitness was examined using the Assessing Level of Physical Activity (ALPHA) and health-related fitness test battery for youth (Castro-Pinero et al., 2010; Ruiz et al., 2011). Reliability of the ALPHA health-related fitness test was good in adolescents with DS with some adaptations, which have been reported elsewhere (Tejero-Gonzalez et al., 2013). All assessments were conducted with one or two instructors to guide and help the adolescents when necessary. Muscular fitness was measured using the handgrip strength and the standing long jump test (lower limb explosive strength). To assess handgrip strength, a hand dynamometer with an adjustable grip (TKK 5101 Grip D, Takey, Tokyo Japan) was used. The adolescents with DS squeezed the dynamometer gradually and continuously for at least 2-s in sitting position, performing the test with both hands and with the elbow in full extension (Tejero-Gonzalez et al., 2013). The test was completed twice and the maximum score in kilograms for each hand was recorded, and the average score of the left and right hand was calculated. To assess lower limb explosive strength, adolescent had to jump as far as possible from a starting position behind a line standing with feet approximately shoulder’s width apart. The test was completed twice and the longer distance was recorded in centimetres (Ortega, Artero, et al., 2008). A single muscular fitness score was calculated from the two muscular tests. A final muscular fitness score was estimated as the mean of the two standardized scores
430
R. Izquierdo-Gomez et al. / Research in Developmental Disabilities 36 (2015) 428–436
(Martinez-Gomez et al., 2011). The individual score of each test was standardized as follows: Z-standardized value = (value-mean)/SD. Motor fitness was measured using the 4 10 m shuttle-run test of speed-of-movement, agility and coordination. The adolescent was required to run between two parallel lines 10-m apart. They run as fast as possible from the starting line to the other line and they should pick up (the first time) or exchange (second and third time) a sponge that has earlier been placed behind the lines. The test was performed twice and the fastest time was recorded in seconds (Ortega, Artero, et al., 2008). Since the lower the score, the better the performance, it was multiplied by 1. Hence, a higher score indicates a better motor fitness. Cardiorespiratory fitness was measured using the 20-m shuttle-run test. The adolescents were required to run between two lines 20-m apart, while keeping pace with a pre-recorded audio CD. The initial speed was 8.5 km/h, which was increased by 0.5 km/h each minute (1 min equals one stage). The adolescents were instructed to run in a straight line, to pivot on completing a shuttle (20-m), and to pace themselves in accordance with the audio signals. The test was finished when the adolescent failed to reach the end lines concurrent with the audio signals on two consecutive occasions. The score for adolescents with DS was the number of laps completed (Ortega, Artero, et al., 2008). Physical activity. The Actigraph accelerometer, models GT1M, GT3X and GT3X+ (ActigraphTM, Pensacola, FL, USA), were used to direct measure objectively PA. This accelerometer has been widely validated in laboratory settings and free-living conditions with children and adolescents without disabilities (Freedson, Pober, & Janz, 2005). Recent studies have showed that there is strong agreement among the three models (Robusto & Trost, 2013; Vanhelst et al., 2012). Adolescents were instructed to wear the accelerometer for 7 consecutives days at the lower back fitted with an elastic belt, excepted during sleep hours and water-based activities. The Freedson’s age-specific cut-points were used to estimate intensities of total PA, moderate PA and vigorous PA (Freedson et al., 2005). Variables obtained by the ActiGraph accelerometer were analyzed as counts per minute (cpm) for total PA and min/day for levels of PA. The time spent in moderate-vigorous PA (MVPA) was computed by summing the time in moderate and vigorous PA intensities (min/day). This score was also dichotomized into two categories ( 0.05) (Fig. 1).
Table 2 Differences in levels of fatness and fitness among adolescents with or without Down syndrome.
Age (years) Weight (kg) Height (cm) Body mass index (kg/m2) Body fat (%) Waist circumference (cm) Muscular fitness (Z-score) Motor fitness (sec 1) Cardiorespiratory fitness (laps)
Down syndrome
Non-Down syndrome
n
n
100 100 100 100 100 100 97 98 98
15.43 2.54 52.61 12.25 148.20 9.56 23.78 3.96 34.88 12.76 73.36 9.42 0.66 0.58 19.22 4.49 8.21 5.96
100 100 100 100 100 100 100 100 100
13.57 1.74 54.98 11.42 161.76 11.29 20.85 2.90 19.61 8.36 68.20 6.23 0.66 0.70 11.91 1.13 50.54 23.84
DS vs. non DS Mean difference (95% CI)
1.86 2.38 13.58 2.93 15.27 5.16 1.31 7.31 42.32
(1.25 to 2.5) ( 5.66 to 0.91) ( 16.48 to 10.65) (1.98 to 3.90) (12.26 to 18.28) (2.93 to 7.38) ( 1.50 to 1.14) (6.40 to 8.22) ( 47.22 to 37.43)
Statically significant are showed in bold. Values are mean SD. P1, unadjusted; P2, age-adjusted.
Cohen’s d
P1
P2
0.85 0.20 1.30 0.84 1.42 0.65 2.05 2.24 2.43
