Screen time between Portuguese and Brazilian children: a cross-cultural study

Abstract

AIMS

To verify differences in screen time (ST) (hours watching TV, using computer and/or video game) and to compare the percentage of meeting ST recommendation between Portuguese and Brazilian children.

METHODS

The sample comprised 369 children aged 9 year-old from Portugal (n=95) and Brazil (n=274). ST average (h/day), physical activity (PA) and socioeconomic status (SES) were estimated by parental-report questionnaire. The Student t test or the Mann-Whitney U test and binary logistic regression analysis were used to verify differences and associations on ST (<2h/day) between cities. All analyses were stratified by gender and adjusted for age, BMI, PA and SES.

RESULTS

The prevalence of meet ST recommendation was 66.7% and 55.3% between Portuguese girls and boys and 25.0% and 16.4%between Brazilian girls and boys. Portuguese girls (1.58±0.84vs3.40 ± 1.76h/day, p<0.05) and boys (1.74 ± 1.18 vs 4.20 ± 2.30 h/day, p<0.05) had significantly less ST than their Brazilian counterparts. Brazilian girls (OR=7.593; p=0.0001) as well as Brazilian boys (OR=6.564; p=0.0001) were more likely to do not meet ST recommendation, compared with their Portuguese counterparts.

CONCLUSIONS

Portuguese children were approximately seven times more likely to meet ST recommendation than Brazilian children. Differences between countries should be considered in public policy strategies to reduce ST.

Keywords
sedentary lifestyle; cross-cultural comparison; children

Introduction

There has been an increased interest in research related to sedentary behavior (SB) and its correlates around the world¹,². SB, typically defined as activities that do not increase energy expenditure substantially above the resting level (≤1.5 METs)while in a sitting or reclining posture such as sleeping, sitting, lying down, and watching television, and other forms of screen-based entertainment³, has been measured by accelerometry as an objective approach and self- or proxy-report questionnaires, as a subjective approach⁴.

Currently, media, from television to the “newmedia”, including cell phones, tablets, and social media, are a dominant force in children’s lives⁵. Therefore, international guidelines recommend that children and adolescents should minimize the time they spend being sedentary each day to reduce health risks. This may be achieved by limiting the amount of total entertainment screen time (ST) to <1 to no more than 2 h/day, keeping the TV set and internet-connected electronic devices out of the child’s bedroom and break up long periods of sitting as often as possible⁵,⁶.

A systematic review examining the relationship between ST and health indicators in school-aged children and adolescents suggested that daily TV viewing in excess (≥2 hours) was associated with reduced physical and psychosocial health, and that lowering sedentary time leads to reductions in BMI⁷. This was true for all study designs, involving 39 countries, using both direct and indirect measurements, and regardless of participant sample size⁷. An updated publication with data from 71 different countries showed that higher duration of TV viewing and/or ST (e.g., TV, computer, electronic games) was associated with unfavorable health⁸. A gradient was observed across health indicators, indicating that less SB, especially ST, was associated with better health⁸. Further, the overall findings from a global matrix comparing 15 countries suggested that when SB was high, physical activity (PA) levels are lower, along with a significant global variation in SB⁹, suggesting that international comparisons can illustrate potentially important patterns and trends on SB⁹. The current globalized society, unhealthy behaviors can easily be set up in the person's lifestyle. Therefore, a cross-cultural vision may be particularly useful in understanding differences in lifestyle behaviors, and help to understand how different environments and diverse cultures may impact on ST. It is also worthy to contribute for assist interventions and policy recommendations.

In a population surveillance, 58.2% of the Brazilian children up to 9 year-old and 58.8% of the Brazilian adolescents aged 10-17 year-old spent more than 3h/day watching TV ¹⁰. The Brazilian National School-Based Health Survey (Pesquisa Nacional de Saúde do Escolar - PeNSE) showed that 60.0% of adolescents spend ≥ 2 h/day watching TV all over the country during weekdays and when asked about the time they were seated in a common weekday not only watching TV but performing other activities such as using the computer, playing video games or doing other sitting activities, 56.1% reported getting more than three hours sitting¹¹. In parallel, approximately 60% of Portuguese children aged11-year-old watched TV for ≥2h on weekdays¹², while 12.2% of children aged between 6-13 year-oldspent less than 1.5 hours watching TV and playing video games, either on weekdays or weekends¹³. Thus, we target to contribute in this field of knowledge, pointing out differences between distant countries geographically and culturally that should be considered whereas worldwide studies are recently paying attention on the increased prevalence of ST among children and adolescents¹⁴-¹⁶ and it has been reported with negative health outcomes^{1, 17-19}. Therefore, this study aimed to verify differences in ST (i.e. hours watching TV, using computer and/or video game) and to compare the percentage of Portuguese and Brazilian children meeting the ST recommendation (< 2 h/day).

Methods

Participants

In this school-based cross-sectional study, a convenience sample of 369 out of 1.021 children aged 9.83 ± 0.65 year-old was selected from Matosinhos, Portugal(n=95), and Uberaba, Brazil (n=274). Data from Portugal derived from the longitudinal project named Preschool Physical Activity, Body Composition and Lifestyle Study (PRESTYLE) and it was collected in the fall of 2013 and 2014. Data from Brazil derived from the cross-sectional study named “Infância Ativa” and it was collected in the spring of 2011 and 2012. It was scheduled meeting with school principals and it was presented the objectives and measures of the study for their agreement to participate. After informed written consent from parents or guardian consent children were evaluated during school days by trained professionals.

The comparison in the current study was between two different cities from very diverse cultural, social, and environmentally countries. Portuguese data were collected in Matosinhos, included in the metropolitan area of Porto located in the North region of the country. It has 62,2 km² of area, 175.478 inhabitants and 2821 inhabitants/km² as demographic density²⁰. Portugal’s Human Development Index (HDI) value for 2014 was 0.830, which put the country in the very high human development category, positioning it at 43° out of 188 countries and territories²¹. Brazilian data were collected in Uberaba located in the South-Eastern region of the country. It has 4533.81 km² of area, 295.988 inhabitants and 65.29 inhabitants/km² as demographic density²². Brazil’s HDI value for 2014 was 0.755, in the high human development category and 75° position²¹.

Anthropometry

Body mass was obtained by digital electronic scale with a150 kg maximum capacity and 100 g accuracy (Plena, modelo ICE, Brazil;Tanita Inner Scan BC 532, Portugal). The height was obtained using a portable stadiometer with a 2 m length and a scale of 0.1 cm (Welmy, Brazil; Holtain, Portugal). The average of two measurements was used for both height and weight. Body mass index (BMI) was calculated by dividing body mass (kg) by square of height (m).

Socioeconomic status

Parents’ education level was used as measure of socioeconomic status²³based on the Portuguese and Brazilian educational system. The SES was categorized as low (9 years’ education or less sub secondary level), middle (10-12 years’ education-secondary level) and high education (higher education). The highest level of education from mother or father and the children’s principal guardian for mono-parental families were selected.

Lifestyle questionnaire

Children’ ST and PA were assessed using a parent-reported lifestyle questionnaire. Parents were asked to recall the total average duration their child watched TV, used the computer and used videogames. The questions were made separately for weekdays and weekend days and reunited to analyzes (Cronbach's α: Brazil = 0,71; Portugal = 0,77). There were seven response categories offered and converted in the corresponding hours: 1 = not at all, 2 = 30 minutes, 3 = 1 hour, 4= 2 hours, 5 = 3 hours, 6 = 4 hours, 7 = >4 hours. The average time spent per day (h/day) engaged in these sedentary activities was calculated and considered the ST for the analyses. PA was considerate as a dichotomous adjustment variable based on positive or negative responses, regarding the children participation in organized sports outside school, classify as active, or not, not active. We assumed that engagement in organized sports is related to higher levels of objectively measured moderate PA, vigorous PA and achieving the recommended levels of MVPA in youth ²⁴.

Statistical Analysis

The Kolmogorov Smirnov test was used to verify the normal distribution of variables. Subsequently, Independent Student t test or Mann-Whitney U test were used to examine differences between cities and gender. Chi-square test evaluated the difference in prevalence between parental education and physical activity between countries. Binary logistic regression analysis was used to evaluate the magnitudes of the associations between ST recommendation and cities. Overall analyses were adjusted for age, BMI, PA and socioeconomic status, within genders. Data analysis was performed using SPSS version 22. The level of significance was set at 0.05.

Results

The descriptive characteristics of the sample are shown in Table 1. For total sample, the variables of age (9.43 ± 0.45 vs 9.97 ± 0.66; p < 0.05), BMI (19.07 ± 3.29 vs 18.22 ± 3.90; p < 0.05) and ST (1.66 ± 1.02 vs 3.79 ± 2.08; p < 0.05) were significantly different between Portuguese and Brazilian children, respectively. There was no difference in parental education prevalence between the two countries (χ² = 4,23; p = 0,121) and Portuguese children participated in organized sports outside school significantly more than Brazilian children (χ² = 32,30; p = 0.0001). ST was significantly lower in Portuguese children than Brazilian children, regardless of gender. BMI was significantly higher in Portuguese than Brazilian boys.

Table 1
Descriptive characteristics (mean (standard deviation) or percentage)

• ^Note
  ST: screen time; BMI: body mass index.
• ^*
  denote significant difference between cities, within gender (p<0.05);
• ^**
  denote significant difference between gender, within city (p<0.05).

The binary logistic regression analysis pointed out the relationship between ST and cities, by gender (Table 2). Regarding the ST, the prevalence of meet the recommendation (< 2 h/day) was 66.7% and 55.3% between Portuguese girls and boys and 25.0% and 16.4% between Brazilian girls and boys, respectively. Further, our data also showed that Brazilian girls (OR=7.593; p=0.0001) as well as Brazilian boys (OR=6.564; p=0.0001) were more likely to do not meet ST recommendation, compared with Portuguese girls and boys, respectively.

Table 2
Association between screen time recommendation and cities, by gender, in children from Matosinhos, Portugal and Uberaba, Brazil

• ^*
  Adjusted by age, body mass index, physical activity and socioeconomic status.

Discussion

This study aimed to verify differences in ST and to compare the percentage of Portuguese and Brazilian children meeting the ST recommendation (<2 h/day). Our major finding was that Portuguese girls and boys presented significantly lower time spent in ST than Brazilian children. The majority of Portuguese children meet the ST recommendation (61.1%) while the Brazilian children (20.8%) did not. Brazilian girls were 7.4 times more likely to do not meet the ST recommendations than Portuguese girls while Brazilian boys were 6.7 times more likely to do not meet the ST recommendation than Portuguese boys. These data may be important in understanding cultural differences and assist ST recommendation between children from different geographical locations.

Culturally, Brazilian children have only a half-day period at school (morning or afternoon). Given that organization, Brazilian children spent approximately only four hours at schools while the remaining time might easily be spent at home with access to TV, computer and video games. Further, significant differences between SES groups was found for sedentary behavior with higher SES groups spending less time watching TV than low SES groups²⁵. Additionally, parental education maybe inversely related with your child ST when considered correlates as presence of TV in the child's bedroom, eating meals in front of a TV, parental modeling for TV/DVD and parental co-viewing²⁶. This scenario contributes for children to stay in front of screens and often without adult supervision even during their leisure time. Rather, the Portuguese educational system provides full-time schools which reduce the time available for ST. Suggesting a potential impact of the time organization and management which lies on social, geographic and cultural environmental factors that should be considered. However, it seems that a single strategy to reduce sedentary behavior measured by accelerometer²⁷ and ST may be unlikely to be effective across many countries¹. Guidelines or recommendations are not common in developing countries yet and it seems that public health messages about limiting ST, in particular, may be important as there are changes in lifestyles occurring throughout all over the world⁹. Additionally, in Portuguese schoolchildren, the prevalence of overweight is high^{28, 29},around 30.0%³⁰-³² and it is among the highest in Europe³¹. However, stabilization seems to have occurred during the last decade²⁹,³²,³³. Increased BMI have been observed in the Brazilian population, even in comparison to children from other countries³⁴, although there are variations in the prevalence rates of overweight and obesity in the different regions of Brazil, the values identified are high and worrying³⁵.

Few international studies involving data from Portugal showed that 45% of girls and 52% of boys aged 11 year-old did not meet the ST recommendation³⁶ and it was found ST prevalence between 14.5 to 17.5 h/week in children aged 6-8year-old³⁷. The ISCOLE was the only study that compared data from Portugal and Brazil adding interesting findings including Portugal among the countries with high level of sitting time assessed by accelerometer (9.2 h/day) and with ST values below the ISCOLE average (2.3 h/day) while Brazil showed sitting time values below the ISCOLE average (8.3 h/day) and it had the lowest percent of participants meeting the ST guidelines (27.6%)¹.

The lower values of ST and high prevalence of meet the ST recommendation in Portuguese children can be found in other studies with Portuguese samples, such as data from Portuguese Prevalence Study of Obesity in Childhood, with 1.517 children aged 7-10 year-old, found around only 28% of boys and 26% of girls watched≥2 h of TV³⁸, while data from Braga, North of Portugal, in children aged 8-10 year-old showed 1.4 h/day ST^{39, 40}. However, higher values of ST in Portuguese youngsters were also described approaching our Brazilian outcomes. For instance, data from urban and rural communities in the Portuguese Midlands comprising 100 boys and 115 girls aged 13-14 year-old found 3.34 ± 1.79 h/day and 2.63±1.39 h/day of ST, respectively⁴¹.

Recently, a systematic review described the methodological characteristics and assessed variables associated with SB among Brazilian children and adolescents and identified a great number of cross-sectional studies around the country⁴². Besides a global matrix comparing 15 countries suggest that SB in general are better in low-income countries⁹, we found high ST values (Girls: 3.36 ± 1.83; Boys: 4.2 ± 2.28 h/day; p<0.05) and prevalence of ST ≥2 h/day (Girls: 81.0%; Boys: 76.4%). Despite that, our data seems to be in accordance with recent studies. For instance, data from 879 adolescents aged 14-19 year-old from São José, Santa Catarina, showed that they spent 6.5 ± 4.9 hours (85.4% ≥2 h/day) in front of TV, computer and videogame, 7.0 ± 4.9 h (90.3% ≥2 h/day) among boys and 5.9 ± 4.8 h (81.2% ≥2 h/day)among girls⁴³. Data from 515 boys and 716 girls aged 14-17 year-old from Londrina, Paraná, found that most adolescents (93.8% of boys and 87.2% of girls) spent ≥2 h/day in ST⁴⁴. Data from the 1993 Pelotas birth cohort study showed that the frequency of adolescents that did not accomplished the ST recommendation was 75% (median 4.5 h/day), 80.2% (median 5.5 h/day) and 77.4% (median 4.5 h/day) at 11, 15 and 18 year-old, respectively. Those values were very similar between boys (75.6 %, 82.3% and 78.8% at 11, 15 and 18) and girls (74.5%, 78.3% and 76% at 11, 15 and 18)⁴⁵.

In addition to these figure, the ST can happen in different ways in their assessments. A representative sample of 8,610 Portuguese adolescents aged 11-17 year-old, from three different cohorts in 2002, 2006, and 2010 found that for the two screen-based media assessed there was a trend reversal. Time spent watching TV/video/DVD decreased significantly from 2002 to 2010 for boys and girls. Conversely, time spent on the computer increased significantly over the years for boys and girls⁴⁶. In Brazil, a comparative analysis of two cross-sectional surveys including 5.028 and 6.529 students in 2001 and 2011, aged 15-19 year-old from Santa Catarina state found a decrease in TV watching after a decade and this appears to be compensated by the increased time spent in computer/video game use, either in boys orgirls⁴⁷. Therefore, children may behave differently according to the different screens/devices and we must take this into account.

Our study has some limitations that should be mentioned. The cross-sectional design provides associations but not causal relationships. The sample contains information of only one city of each country, so the results here should be interpreted with caution and attention to generalizations. Measures of ST and PA relied on parent-report and were possibly biased. Unfortunately, there are not yet, self-report or proxy-report sedentary behavior questionnaires for children and adolescents available that are both valid and reliable⁴⁸. Besides that, we did not evaluate the use of new media such as handheld videogames, cell phones and music devices that recently has contributed to increased screen time⁴⁹.

Conclusions

Portuguese children were approximately seven times more likely to meet the ST recommendations than Brazilian children. Difference between countries should be considered in public policy strategies to reduce ST. More research is needed to confirm and expand this data.

Acknowledgment

The group thanks to the children, their parents, as well as the staff from all schools. This study was supported by CIAFEL (Faculty of Sport, University of Porto) and by the following Portuguese Foundation for Science and Technology (FCT) grants: UID/DTP/00617/2013; SFRH/BD/86538/2012; And sponsorship grant by Coordination for the Improvement of Higher Education Personnel (CAPES) Nº 6099/13-0.

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Publication Dates

• Publication in this collection
  2017

History

• Received
  11 Oct 2016
• Accepted
  13 Dec 2016