Abstract
Objective:
The aim of this study was to objectively measure physical activity and its association with sociodemographic factors among Malaysian primary school-age children.
Methods:
A total of 111 primary school children in Kuala Lumpur were selected through random sampling. Activity pattern was determined using pedometers and differences by sex, ethnicity and body mass index categories were analysed. The relationship between pedometer-determined physical activity and sociodemographic factors were also studied.
Results:
Overall, boys attained significantly higher daily step counts than girls (9573 ± 4145 vs 7313 ± 2697). Significant difference in daily step counts between boys and girls were observed during weekdays (p<0.01), weekends (p<0.05) and total mean step counts (p<0.01). Malay ethnicity showed higher daily step counts during weekdays than weekends (p<0.05). Compared with boys, girls had higher odds (OR=5.58; 95% CI 1.12, 27.77) of not meeting the recommended daily step counts. Those who had low physical activity levels had higher odds (OR=15.75; 95% CI 1.78, 139.33) of not meeting recommended daily step counts than children who had moderate physical activity level.
Conclusion:
Boys were significantly more active than girls and physical activity was greater during weekdays than on weekends. The primary schoolchildren in Kuala Lumpur were sedentary, with minimum physical activity being observed. Differences in sexes and physical activity levels influenced pedometer step counts in children.
Keywords
Introduction
Physical inactivity, along with other lifestyle-related health risk factors such as unhealthy diet, tobacco use and alcohol consumption, is becoming increasingly prevalent in developing countries that face rapid economic and social development, urbanization and industrialization. 1 Although participation in physical activity imparts numerous benefits in reducing non-communicable diseases, such as obesity, coronary heart disease, stroke, non-insulin–dependent diabetes, certain types of cancers and all-cause mortality,2–4 the majority of the population, including children and adolescents, is not physically active. 5
In the United States (USA), an expert panel reviewed the literature on physical activity and recommended that children and adolescents engage in moderate to vigorous, enjoyable and developmentally appropriate physical activity daily for 60 minutes or more. 6 To date, prospective and cross-sectional studies have observed that most childhood populations have limited physical activity. One study in the United Kingdom (UK) showed mean moderate to vigorous physical activity (MVPA) to be 19.7 minutes among 12-year-olds 7 ; while another study in the USA showed that only 42% of 6- to 11-year-olds had 60 minutes of physical activity daily, and only 8% of adolescents achieved this recommendation. 8 In Taiwan, 80% of adolescents engage in some physical activity; however, only 28.4% meet the recommendation. 9 A Singapore study revealed that adolescents appear to have higher pedometer step counts outside school than within school (mean (SD): 5568 (4796) vs 3881 (3149)). 10 Secondary data analysis using the Global School Health Survey dataset by the World Health Organisation (WHO) 11 revealed that over a seven-day period, only 23.9% of boys and 16.4% of girls in the tropics meet the physical activity recommendation of at least 60 minutes daily. 12
In Malaysia, the lack of physical activity among children and adolescents has been confirmed through a number of questionnaire-based studies. A 2012 nationwide Malaysian school-based nutrition survey reported 57.3% of school-going adolescents aged 10 to 17 years were physically inactive. 13 Farah Wahida et al. 14 reported that boys (35.0%) in Kuantan, Pahang, were more physically active than girls (17.3%). Adolescents from Sarawak were reported to display low physical activity, with 65.9%, 31.7% and 2.4% having low, moderate and high physical activity levels, respectively. 15 A recent study by Wong and colleagues revealed that sociodemographic characteristics are important factors in determining the physical activity domains among children. 16 Although these data on physical activity levels are available, studies employing objectively measured physical activity among children are still limited.
To date, there have been only three published studies reporting objectively measured physical activity in Malaysia children. Wafa et al. found obese children have significantly higher sedentary time spent compared with healthy-weight children. 17 Obese children also were found to accrue the greatest number of sedentary bouts during weekdays rather than at the weekend. 18 Similarly, Lee and colleagues found low levels of physical activity and high levels of sedentary behaviour among children aged 7 to 12 years, with 84.8% not meeting pedometer step count recommendations. 19 The same study also reported that Physical Activity Questionnaire (PAQ) scores and pedometer step counts were negatively associated with body mass index (BMI)-for-age Z-score, percentage body fat and waist circumference (WC). 19 However, these studies reported differences in physical activity levels only between sex and weight categories, while studies on sociodemographic factors, especially differences between ethnicity with pedometer step count among Malaysian children, remain scarce.
Hence, to address this gap in knowledge, this study aimed to measure physical activity levels among primary school-aged girls and boys and record patterns of physical activity between weekdays and weekends. Differences between the sexes, ethnicities, BMI category and physical activity levels were also analysed, and the influence of sociodemographic factors on recommended daily pedometer step counts was also studied. As Malaysia is a multiethnic country comprising mainly Malay, Chinese and Indian ethnicities who practise different cultures and lifestyles, the association of ethnicity with daily pedometer step counts is also of interest.
Methods
Study design
This cross-sectional study on pedometer-assessed physical activity was conducted as part of a larger study that examined diverse variables related to metabolic syndrome in primary school children aged 9 to 12 years. 20 The main study consisted of 402 children who were randomly selected from nine schools in Kuala Lumpur and its metropolitan suburbs, with a response rate of 44.9%. 20 Based on sample size calculation, a subsample of 30% of participants from the main study was then selected by simple random sampling to participate in this pedometer study. In each school, the selected children were then given a copy of the pedometer consent form. Children whose parents did not agree to their participation in the pedometer study were further excluded. Participants were then recruited until the desired sample size was achieved.
Healthy children aged between 9 and 12 years not on any medication at the time of the study were invited to participate in the main study. Children were excluded if they had any disease or syndrome that may affect the fat distribution or body composition based on information provided by the parents, had writing or speaking problems, or had not fasted the day of data collection.
Participants
Sample size for this pedometer study was determined by using Epi Info version 6 software. Referring to the 2008 study by Laurson et al., 21 we used a prevalence of 20.0%, which meets the pedometer step count recommendation. The power of study and confidence level was set at 80% and 95%, respectively, odds ratio (OR) at 3.5, and the suggested minimum sample size would have been 112 participants in total for both sexes. With an assumed 30% drop-out rate, the final total sample size was 146 children.
The 134 children studying at six primary schools in Kuala Lumpur participating in the study indicated a response rate of 91.8%. Approval was received from the Research Ethics Committee of Universiti Kebangsaan Malaysia, Ministry of Education, and school principals before the study was conducted. Parental written informed consent and child verbal assent were obtained prior to data collection.
Twenty-three children (17.2%) were subsequently excluded from this analysis because of incomplete pedometer data of fewer than 1000 steps, fewer than eight hours of wearing time and minimum numbers of valid days of two weekdays and one weekend day, resulting in a final sample of 111 participants in our analysis.
Sociodemographic variables
Sociodemographic characteristics of the children were obtained through a self-administered questionnaire filled in by the child’s parents or guardians, collecting information such as the child’s age, sex and ethnicity. Monthly household income was also parent-reported and then categorised into two groups: low socioeconomic status (Ringgit Malaysia (RM)) (<RM3500) and high socioeconomic status (>RM3500).
Anthropometry and body composition assessments
Weight was recorded in light clothing to the nearest 0.1 kg on a SECA digital weighing scale Model 813 (SECA, Germany), and height was measured without shoes to the nearest 0.1 cm using a SECA stadiometer Model 214 (SECA, Germany). WC was measured using a SECA measuring tape Model 200 (SECA, Germany) to the nearest 0.1 cm over skin, midway between the 10th rib and the iliac crest. The average of two values for each measurement was used in the data analysis.
BMI was calculated from weight and height, and the 2007 WHO growth reference 22 was used to categorise the children based on BMI-for-age Z-score (BAZ) into non-overweight/obese (BAZ <1 SD) and overweight/obese groups (BAZ ⩾1 SD). Fat mass (FM) and fat-free mass (FFM) were measured using bioelectrical impedance analyses, Maltron BioScan 916 (Maltron, UK). Participants fasted overnight prior to the day of data collection, and measurement was taken after the participants had emptied their bladder and rested in a supine position for 5 to 10 minutes.
Physical activity assessment
Objective measurement of physical activity
Physical activity was assessed using the Omron pedometer Model HJ 113 (Omron, Japan) for seven consecutive days. The Omron pedometer Model HJ113 is a reliable and valid device to measure children’s ambulatory activity 23 and has demonstrated high accuracy when validated against a treadmill at all speeds. 24 Participants were given information sheets with instructions prior to wearing the pedometer. Participants placed the pedometer in the right pocket of their school uniform, and during weekends wore pants or a skirt with pockets to ensure that the pedometer was kept in the same position. Participants were instructed to wear the pedometer upon waking up in the morning and to remove the pedometer before going to bed, as well as for activities involving water, such as swimming or showering. Participants were reminded to go about their usual activities during the pedometer-wearing period. Additionally, participants were also given a pedometer form to verify that the pedometers were worn for the entire time of the study.
Daily step counts were stored in the internal memory of the pedometer, enabling recall of each day’s step counts upon collection of the pedometer at the end of seven days. The average pedometer step counts for weekdays and weekends were then calculated. Daily step counts of fewer than 1000 steps and fewer than eight hours wearing time 25 were excluded from analysis, and a minimum of at least two weekdays and one weekend day of acceptable counts were needed for the calculation of average pedometer step counts. Based on pedometer steps recommendation by Tudor-Locke and colleagues, cut-off values of 13,000 steps and 11,000 steps per day were used for boys and girls aged 9 to 11 years, respectively, while for adolescents aged 12 years, a cut-off of 10,000 steps per day was applied to both sexes. 26
Subjective measurement of physical activity
Physical activity was assessed subjectively using the modified Physical Activity Questionnaire for Older Children (PAQ-C),27,28 which was validated by Wilson et al. 29 The questionnaire was translated into the Malay and Chinese languages and back-translated into English for consistency and accuracy. The translated questionnaire was also pretested among children aged 9 to 12 years before data collection. Activity patterns during school, physical education (PE) classes, recess time, after school, during the weekend, as well as leisure time activities and sedentary behaviours were assessed. Participants were asked to recall activities over the past seven days. Physical activity level was then determined based on a five-point scale, with ‘no activity’ scoring 1, and ‘7 times or more’ scoring 5. Final composite scores were then calculated. Lower scores indicated low physical activity level and vice versa. Overall physical activity, based on Dan and colleagues, 30 was designated low (1.00–2.33), moderate (2.34–3.66) or high (3.67–5.00).
Statistical analysis
Data were analysed using the Statistical Package for Social Sciences version 16.0 (SPSS Inc, Chicago, IL, USA). Appropriate statistical analysis was carried out with a two-sided alpha level of 0.05 or 95% confidence interval (CI). For continuous data, descriptive analyses were reported as means and SD. Independent t-test, paired t-test and one-way analysis of variance were employed to analyse continuous dependent variables. Binary logistic regression analysis was employed to test the association between demographic factors like age, sex, socioeconomic status, BMI category and ethnicity with the recommended daily pedometer step counts. Association between subjectively measured physical activity levels with recommended daily pedometer step counts were also further explored. Observed associations were expressed as OR with 95% CIs.
Results
Participants included 46 boys and 65 girls with mean ages of 11.0 ± 0.8 years and 10.9 ± 0.9 years, respectively. The sample population was made up of 64.0% Malay, 20.7% Chinese and 15.3% Indian participants. Table 1 shows the physical characteristics of the participants by sex. The differences in weekday and weekend patterns of daily pedometer step counts and physical activity levels by BMI category, sex and ethnicity are shown in Table 2. Boys and girls alike showed low physical activity level with a mean score of 1.92 (95% CI: 1.86, 1.99). Among the three ethnic groups, Indians were found to have slightly higher self-reported physical activity levels compared to Malays and Chinese; however, the differences were not significant. There were also no significant differences in physical activity level between the BMI categories. For pedometer step counts, boys attained significantly higher overall mean daily step counts (9573 vs 7313, p<0.01), weekday step counts (9938 vs 7463, p<0.01) and weekend step counts (9208 vs 7163, p<0.05) than girls. However, there were no significant differences in pedometer step counts during weekdays or weekend days among BMI categories as well as ethnicities. For comparison of mean step counts during weekdays and weekend day, paired sample t-test revealed that a significant difference was observed for Malay children whereby they were found to be more active during weekdays than weekends (8713 vs 7867, p<0.05).
Physical characteristics of participants (n = 111).
BAZ: BMI-for-age Z score; BMI: body mass index.
Differences in weekday and weekend pattern and mean (SD) steps count by BMI categories, sex and ethnicity.
PAL denotes physical activity levels.
BMI: body mass index; PA: physical activity; PE: physical education.
Independent t-test showed mean values were significantly different between the sexes during weekday steps/day, at bp<0.01, during weekend steps/day at cp<0.05 and daily mean steps/day, at bp<0.01.
Paired sample t-test showed mean values were significantly different between weekday steps/day and weekend steps/day within Malay ethnicity at dp<0.05.
Figure 1 shows the mean total daily pedometer step counts for the various age groups. Table 3 shows the association between sociodemographic factors and achieving the recommended pedometer steps guidelines. Only 18.0% of children (28.3% boys and 10.8% girls) met the minimum daily pedometer steps of 13,000 (boys) and 11,000 (girls) recommended for 6–11 years; and 10,000 steps recommended for 12 years and older. 21 Girls were found to have higher odds (OR=5.58; 95% CI 1.12, 27.77) of not meeting the recommended step count compared with boys. Children with low physical activity level had odds of 15.75 (95% CI: 1.78, 139.33) of not meeting recommended daily step counts compared with children with moderate physical activity levels. For other sociodemographic characteristics such as age, socioeconomic status and ethnicity, we could not find any significant association with achievement of recommended step counts.
Differences in pedometer step counts among age groups.
Association between sociodemographic factors and meeting recommended guidelines a .
According to Tudor-Locke et al. 26
Measured by the Physical Activity Questionnaire for Older Children.
OR calculated from logistic regression test by using enter method.
BMI: body mass index; CI: confidence interval; OR: odds ratio.
Discussion
Our study indicates that the majority of children (82.0%) in Kuala Lumpur do not meet the minimum recommended step counts and can thus be considered as physically inactive. Boys had an average of 9573 steps per day while girls had 7313 steps per day. Malay children were typically more active during weekdays than at weekends. Only a small percentage of children (28.3% boys, 10.8% girls) met the recommended step counts. Similarly, another local study also reported a high proportion (84.8%) of children not meeting the recommended daily pedometer step count. The mean step counts of boys (9708) and girls (8339) of that study were similar to our results. 19 Contrary to studies in other countries where higher step counts were recorded, for example in New Zealand (16,133 daily step counts for boys and 14,124 daily step counts for girls), USA (12,709 daily step counts for boys and 10,834 daily step counts for girls), Saudi Arabia (13,489 daily step counts for boys) and Sweden (16,973 daily step counts for boys and 15,141 daily step counts for girls), our study indicates much lower daily step counts in Malaysian children.31–34 We also observed sex differences, with boys demonstrating significantly more step counts than girls during weekdays, weekends, and overall on average. Results from the physical activity questionnaire showed that boys engaged in more activities during recess, outside school and during weekends, resulting in higher total physical activity scores than girls. This implied that boys were more physically active than girls. Such results were similar to studies conducted in most countries, including in New Zealand, 31 the USA, 32 Sweden 33 , Canada 35 and Cyprus. 36
Between the two sexes and among Malay schoolchildren, daily step counts were observed to be higher during weekdays as compared to weekends. Possible explanations for higher step counts include involvement in more physical activities during school days (e.g. PE class), or after-school activities in which participation in the co-curriculum activities are deemed compulsory by the school. However, the influence of segmented activities during school hours on step counts is not conclusive because we were not able to provide relevant evidence. Another study had confirmed that lunchtime physical activity represents the most important source of daily physical activity (15% to 16%) obtained during school hours both for boys and girls, whereas recess accounts for 8% to 9% and PE class accounts for 8% to 11% of total step counts. 37 Regardless, almost half of daily step counts are attributable to after-school activities. 37
Another interesting finding observed from the present study is that Indian children showed higher physical activity scores but lower step counts than other ethnicities. Further analysis on the domains of the physical activity revealed that Indian children were more active during recess time, and before and after school as well as during weekends. Such a phenomenon could possibly be caused by over-reporting of the Indian children, as subjective measurement depends solely on participant recall over the last seven days.
Unexpectedly, we did not find any significant differences in the daily step counts as well as physical activity levels between normal-weight and overweight/obese children, even though another study has shown that overweight/obese individuals had less physical activity and the lowest MVPA reported. 38 As evidenced in a large-scale cross-sectional study in the UK involving 5500 12-year-olds, a strong negative dose response is associated with objectively measured MVPA and FM as well as obesity. 7 Another study in Malaysia conducted among healthy-weight and obese children reported similar results, namely that physical activity levels are low both in normal-weight and overweight children. 17 Interestingly, that study found no significant differences in the amount of time spent in low, moderate and high-intensity activity among 6555 underweight, normal-weight and overweight girls and boys aged 11 to 15 years in Malaysia, which was suggested to be due to the misreporting of activities among the overweight group. 39 We believe children in the overweight/obese group in our study were not severely obese and as such could still have levels of physical activity comparable to their normal weight counterparts.
Children pedometer step counts were found to be lower among the older age groups compared with the younger age group, with an inverse relationship between age and daily step counts. A review paper by Müller et al. 40 further confirmed that physical activity participation decreases with age, with younger youths demonstrating higher physical activity participation than older ones. This implies that children are more active when they are young and that their activity tends to decrease as they grow older. This may be due to the reduction in the number of PE sessions in the upper primary classes because more attention is focused on classroom teaching and preparation for major examinations for all 12-year-olds in Malaysia. Similarly, a study conducted in secondary schools in Peninsular Malaysia also reported that older adolescents (15–17 years) are more inactive compared with younger adolescents (13–14 years). 41 The decrease in activity could also be due to more indoor sedentary activities, such as computer games and watching television, which children prefer as they grow older. 42 Safety issues are also one of the major concerns resulting in parents not allowing their kids to play outdoors. 43 In addition, the humid Malaysian tropical climate with frequent rainstorms during the evening could be part of the reason why children do not participate in outdoor activities.
We found that girls displayed higher odds of not meeting recommended pedometer guidelines than boys. This could be because girls are less active than boys with lower step counts observed. This finding is consistent with a study conducted in Australia among 415 adolescents that found girls who have fewer than 10,000 step counts are found to be significantly more likely to have low cardiorespiratory fitness and more likely to be overweight or obese. 44
Children with low physical activity level as assessed by self-report were found to have higher odds of not meeting the recommended step counts than children with moderate physical activity levels. This supports our findings that children in the lower physical activity levels were not meeting the recommended pedometer step counts. Children who reported lower physical activity level may be more sedentary and less active physically, and thus had lower pedometer step counts. As evident from two longitudinal studies by Arundell and colleagues, 45 there has been a decrease in moderate and vigorous after-school activity, but increased time is spent on sedentary activities among children. This may be explained by increases in screen time usage such as television viewing and usage of other electronic media. In Malaysia, children are also found to spend almost half their sedentary time on screen activities, with an average of 3.1 hours screen time daily. 19
However, we could not find any significant association between age, weight status, socioeconomic status and ethnicity with recommended step counts. According to Metcalf et al., sociodemographic factors do not show any significant association with physical activity, thus suggesting other factors such as biological or environmental factors that perhaps influence individuals to become less active. 46 In another study, Cleland et al. further confirmed that correlates of pedometer-determined activity tended toward being biological in nature, while correlates of self-reported activity were more commonly demographic or behavioural. 25 Another possible reason could be because of the lower power of the present study due to the smaller sample size and its cross-sectional design. Nevertheless, previous studies also found no31,47 or little 48 significant association between step counts and BMI groups.
In view of the high percentage of inactivity among our school children, it is important that action is taken by schools to increase the number of PE classes. Parents should also encourage physical activity and outdoor play and monitor their children while they are playing outdoors. Intervention programs should be targeted at young children because obesity tends to continue into adulthood. 49
The strength of this study is that we reported the physical activity of children in different domains such as structured activities, activities during recess, activities during PE classes, activities outside schools and activities during weekends as featured in the physical activity questionnaire, thus providing children’s overall physical activity patterns. In addition, the use of the pedometer in capturing total step counts provides a more accurate and valid measurement of the children’s activities, thus overcoming the limitations of subjective measurement through questionnaires.
Nevertheless, there are a few limitations of this study. First, the participants were a subsample recruited from an existing sample of the main study. Thus the sample size is relatively small and may be representative only of Malaysian children in Kuala Lumpur. In addition, the pedometer, which records body movements in total step counts, was not able to show the type and intensity of activities. Nonetheless, this study also reported the subjective measures of the PAQ-C, which covers different aspects of physical activities, for example, types and non-incidental activities. Thus, this study has provided an overview of the activity pattern of school-aged children during weekdays and weekends and sex differences in physical activity levels. More sophisticated objective methods of physical activity measurements are needed to further explore the factors affecting physical activity levels among children.
Conclusion
The majority of primary schoolchildren in Kuala Lumpur are considered physical inactive as they (82.0%) did not meet daily pedometer step count recommendations. Only 28.3% of boys and 10.8% of girls met the recommended guidelines for daily step counts. Physical activity was greater during weekdays compared to weekends, with boys being more active than girls. Older children had lower activity counts compared with younger children. In general, urban Malaysian children are sedentary and have minimal physical activity. The findings of this study highlight that sex and physical activity levels are two main factors that influence pedometer step counts in Malaysian schoolchildren aged 9 to 12 years in Kuala Lumpur.
Footnotes
Acknowledgements
The authors would like to thank all participants for their involvement and cooperation, and also their parents for permission and support during the course of this study. We are also grateful to the school principals, teachers, administrators and the Ministry of Education for their cooperation and assistance.
Authors’ contributions
BS Wee and BK Poh researched literature and conceived the study. BS Wee performed the measurements, gaining of ethical approval, participant recruitment and data analysis. AB, AT Ruzita, MN Noor and BK Poh supervised the work. AB aided in interpreting the results. BS Wee wrote the first draft of the manuscript. All authors reviewed and edited the manuscript and approved the final version of the manuscript.
Availability of data
The datasets generated and/or analysed during the current study are available from the first author.
Conflict of interest
The authors declare that there is no conflict of interest.
Ethical approval
Ethical approval to report these cases was obtained from the Research Ethics Committee of Universiti Kebangsaan Malaysia (UKM 1.5.3.5/244/SPP3).
Funding
This project was funded by the Ministry of Science, Technology and Innovation Research Grant (ScienceFund 06-01-02-SF0314) and was partially supported by the International Atomic Energy Agency Technical Cooperation Project (RAS/6/050).
Informed consent
Written informed consent was obtained from all participants and/or their parents before the study.
