Gymnastik- och idrottshögskolan, GIH

Purpose: Beneficial acute effects of dietary nitrate have been demonstrated on working memory in adults, with changes in cerebral blood flow (CBF) being a potential mechanism. However, these effects have not been studied in adolescents. Moreover, having breakfast compared to skipping may also exhibit positive effects on working memory. Therefore, this randomized crossover trial investigated the acute effects of nitrate and breakfast on working memory and changes in task-related CBF in adolescents.  Methods: This trial will recruit at least 43 adolescents (13–15 years old). There were three experimental breakfast conditions: (1) none, (2) regular, and (3) regular breakfast with high nitrate in the form of concentrated beetroot juice. Working memory (1-, 2-, 3-back tests) and task-related CBF (prefrontal cortex oxygenated and deoxygenated-hemoglobin changes estimated using functional near-infrared spectroscopy) were measured immediately after breakfast and 130 min later. The data collection for this study is ongoing, thus results for 35 adolescents are presented here and due to blinding of the researcher we are unable to report at this time in which condition these effects occurred, but will be revealed by the time of the conference, as well as for the results on changes in CBF.  Results: Preliminary results from the ongoing study showed that from pretest to posttest there was a statistically significant improvement in reaction time in all three conditions for all three n-back tests, but no intervention effects. Accuracy, however, improved from pretest to posttest in only one condition, for all three nback tests (β [95% confidence interval] from linear mixed-effects models with subject as random effect: 1-back 2.8[1.2-4.3], 2-back 2.6[0.9-4.2], 3-back 3.6[2.2-5.0]), and there was a tendency towards an intervention effect between this breakfast condition and another on the accuracy of the 3-back test (P for time-by-condition interaction 0.07).   Conclusions: The results from this study will increase our understanding into the effects of breakfast and its composition (i.e., nitrate-rich) on acutely improving working memory in adolescents and the potential mechanisms. In turn, the results will inform on whether policies on providing breakfast in schools should be considered to improve students' cognitive performance.

BACKGROUND: Inorganic nitrate has been shown to acutely improve working memory in adults, potentially by altering cerebral and peripheral vasculature. However, this remains unknown in adolescents. Furthermore, breakfast is important for overall health and psychological well-being. Therefore, this study will investigate the acute effects of nitrate and breakfast on working memory performance, task-related cerebral blood flow (CBF), arterial stiffness, and psychological outcomes in Swedish adolescents.

METHODS: This randomised crossover trial will recruit at least 43 adolescents (13-15 years old). There will be three experimental breakfast conditions: (1) none, (2) low-nitrate (normal breakfast), and (3) high-nitrate (concentrated beetroot juice with normal breakfast). Working memory (n-back tests), CBF (task-related changes in oxygenated and deoxygenated haemoglobin in the prefrontal cortex), and arterial stiffness (pulse wave velocity and augmentation index) will be measured twice, immediately after breakfast and 130 min later. Measures of psychological factors and salivary nitrate/nitrite will be assessed once before the conditions and at two-time points after the conditions.

DISCUSSION: This study will provide insight into the acute effects of nitrate and breakfast on working memory in adolescents and to what extent any such effects can be explained by changes in CBF. This study will also shed light upon whether oral intake of nitrate may acutely improve arterial stiffness and psychological well-being, in adolescents. Consequently, results will indicate if nitrate intake from beetroot juice or if breakfast itself could acutely improve cognitive, vascular, and psychological health in adolescents, which can affect academic performance and have implications for policies regarding school meals.

TRIAL REGISTRATION: The trial has been prospectively registered on 21/02/2022 at https://doi.org/10.1186/ISRCTN16596056. Trial number: ISRCTN16596056.

AIM: Physical activity patterns in adolescents have been associated with general health. Stress, screen-time and sleep are other factors associated with physical activity that influence health in adolescents. Physical activity accounts for several health benefits; however, the impact of organised sports participation to achieve the same health benefits are less explored. This study explored the associations of organised sports participation with general health, stress, screen-time and sleep-duration in adolescents.

METHODS: For this cross-sectional study, data from 1139 adolescents (age 13-14 years) from 34 schools were analysed. Data were collected during autumn 2019. Data collection consisted of self-reported questionnaires and standard methods for height and weight measurements.

RESULTS: Adolescents with organised sports participation ≥3 times/week were twice as likely to report better general health (OR: 2.11, CI: 1.45-3.07) and lower screen-time (OR: 1.98, CI: 1.43-2.74). Adolescents with organised sports participation ≥3 times/week were less likely to meet the recommended sleep-duration on weekdays (OR: 0.43, 95% CI: 0.29-0.65).

CONCLUSIONS: Adolescents with frequent organised sports participation had better general health, lower amounts of screen-time and shorter sleep-duration on weekdays than those with no participation. Although the causal relationships remain unknown, these results can be relevant when developing strategies promoting physical activity and health in adolescents.

BACKGROUND: The COVID-19 pandemic has had major impact on the daily lives of adolescents. This study examined whether mental health outcomes had changed over the pandemic, and if such changes were related to changes in physical activity (PA), sedentary time, sleep, screen time, and participation in organized sports.

MATERIALS AND METHODS: In this longitudinal study, data were collected in autumn 2019 with follow-up measurements in spring 2021. In total, 558 schools were invited and 34 schools around Stockholm with a variation in socioeconomic background were included. Physical activity and sedentary time were measured for seven consecutive days by accelerometry (Actigraph). Anxiety, health-related quality of life (HRQoL), psychosomatic health, stress, sleep duration, screen time, and organized sports participation were self-reported in questionnaires. Linear models were applied to estimate associations between changes in mental health outcomes and exposures.

RESULTS: From the baseline sample of 1,139 participants, 585 (55% girls), mean (SD) age 14.9 (0.3) years, participated in the follow-up. Between 2019 and 2021, there was a decrease in HRQoL [mean difference -1.7 (-2.3, -1.2), p < 0.001], increase in psychosomatic health problems [mean difference 1.8 (1.3, 2.3), p < 0.001], and an increase in the number of participants with high stress [from 94 (28%) to 139 (42%), p < 0.001]. Weekly light PA and sleep duration decreased and weekly sedentary time and screen time increased unrelated to changes in mental health outcomes. An increase in sleep duration during weekdays was significantly related to both a decrease in anxiety (B = -0.71, CI: -1.36, -0.06) and an increase in HRQoL (B = 1.00, CI: 0.51, 1.49).

CONCLUSION: During the COVID-19 pandemic, mental health appears to have been impaired in Swedish adolescents, but unrelated to changes in PA, sedentary time, screen time, or participation in organized sports. However, increased sleep duration on weekdays was related to less anxiety and better HRQoL. The results may help policy makers and other stakeholders comprehend the differential effects of the COVID-19 pandemic on mental health outcomes and help guiding the planning of policy actions.

TRIAL REGISTRATION: ISRCTN15689873.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic had a huge impact on daily life, even in countries such as Sweden where the restrictions were relatively mild. This paper assesses the effects of the COVID-19 pandemic restrictions on physical activity (PA) patterns, screen time, and sleep among Swedish adolescents. The exposures explored include gender, parental education, anthropometrics, and cardiovascular fitness (CVF).

METHODS: Cohort data were collected from September 26th to December 6th, 2019, and from April 12th to June 9th, 2021. Participants were 13-14 years-old (7th graders) at baseline with 585 participating at both baseline and follow-up. At both baseline and follow-up PA and sedentary time were measured with accelerometers, and sleep and screen time with questionnaires. The exposure variables (gender, parental education, anthropometrics and CVF) were collected at baseline. Multilevel linear regression analyses were performed.

RESULTS: Moderate-to-vigorous-physical activity (MVPA) remained unchanged while light physical activity (LiPA) decreased and sedentary time increased. Sleep duration decreased and screen time increased. Girls, adolescents with overweight/obesity (BMI and percent body fat), and those with lower CVF at baseline had less favourable changes in PA patterns, sleep and screen time.

CONCLUSIONS: Although no significant (α = 0.05) changes were seen in MVPA, both LiPA and sedentary time as well as sleep and screen time changed in unfavourable ways. More intense activities are often organised and seem to have withstood the pandemic, while less intense activities decreased. Some groups were more vulnerable and will need directed intervention in the post-pandemic period as well as when future pandemics hit.

Aim

In adults, prolonged periods of sitting have been linked to acute negative effects on vascular structure and function. The aim of this study was to evaluate the acute effects of physical activity (PA) breaks during prolonged sitting on arterial stiffness, cortisol and psychological factors in adolescents.

Methods

Adolescents underwent different short (3-min) breaks starting every 20 min, during 80 min of sitting on three separate days. Breaks were (A) social seated breaks (SOC), (B) low-intensity simple resistance activity PA breaks (SRA) and (C) moderate-intensity step-up PA breaks (STEP). The arterial stiffness measures were augmentation index (AIx), AIx@75 and pulse wave velocity (PWV). Cortisol was measured from saliva. Psychological factors were self-reported.

Results

Eleven girls and six boys (average age 13.6 ± 0.7 years) participated, with average baseline heart rates of 72 ± 11 bpm, systolic/diastolic blood pressure 111 ± 7/64 ± 6 mmHg and cortisol 10.9 ± 5.8 nmoL/L. PWV, cortisol and psychological factors did not change after any of the conditions. AIx@75 increased significantly (4.9 ± 8.7–9.2 ± 13.2) after the STEP intervention compared with SOC and SRA (time × condition p < 0.05).

Conclusion

Arterial stiffness increased after prolonged sitting with frequent, short step-up activity breaks. The results indicate potential important intensity-dependent effects of physical activity on vascular regulation in youth.

Purpose: The COVID-19 pandemic has had an impact on daily life around the world though in Sweden therestrictions have been rather mild. The aim is to explore whether the pandemic has led to changes in physicalactivity (PA) patterns, including sedentary time, Light Physical Activity (LiPA) and Moderate-to-Vigorous-Physical Activity (MVPA) during weekdays and weekends, as well as screen time and sleep. The potentialpredictors explored include gender, parental education, anthropometrics, and cardiovascular fitness (CVF).Methods: Data were collected in the fall of 2019 and the spring of 2021. The participants were 13-14 years-oldat baseline and lived in the Stockholm area. In total 585 participated at both baseline and follow-up. PA andsedentary time were measured with accelerometers and sleep and screen time with questionnaires at baselineand follow-up. The exposure variables were collected at baseline: gender and parental education viaquestionnaire, anthropometrics (BMI and body fat percentage measured with standard methods byresearchers) and CVF with a submaximal test. Multilevel linear regression analyses were performed.Results: MVPA remained unchanged while LiPA decreased by 25.5 minutes on weekdays and 10.3 minuteson weekends (both p<0.001) and sedentary time increased by 9.4 minutes on weekdays (p=0.023). Sleepduration decreased by 27.4 minutes on weekdays and 19.1 minutes on weekends (both p<0.001) and screentime increased by around 45 minutes both on weekdays and weekends (p<0.001). Girls, adolescents withoverweight/obesity (BMI and percent body fat), and those with lower CVF at baseline had less favourablechanges in PA patterns, sleep and screen time.Conclusions: Previous self-reported data seems to suggest a decrease in physical activity due to thepandemic; this study only found such changes to be present in the lower intensity levels of physical activity butnot in the MVPA. It is possible that more strenuous physical activity is more often part of organized sport whichseems to have prevailed in Sweden despite the pandemic while habitual less intense activity decreased. Somegroups were found to be more vulnerable and might need more support to maintain their physical activitylevels, both now in the post-pandemic periods and during future pandemics.

Purpose: Physical activity breaks in schools have been suggested as a promising strategy to acutely improvecognitive performance in children and adolescents. Most previous studies have explored the effects of singlephysical activity bouts, but they are infeasible in a school setting (e.g. long duration/high-intensity or requiringequipment/space). Further, studies investigating the underlying physiological mechanisms in adolescents arelacking. Therefore, the aim of this study was to investigate the effects of short, frequent physical activity breaksof different intensities on adolescents’ working memory (WM) and cerebral blood flow (CBF) during prolongedsitting.Methods: This randomized crossover study was performed in adolescents (13-15 years of age). In 80-minutesessions, one of the following types of breaks was performed four times in three minutes durations on threedifferent days: simple resistance training (SRA), step-up at a pre-determined pace (STEP), or remainingseated (SOCIAL). Before and after each session, WM (accuracy and reaction time during the 1,2,3-back test)were measured, with simultaneous measurement of task-related CBF (assessed by prefrontal oxygenationusing functional near-infrared spectroscopy). Analysis of CBF is ongoing and will be presented at theconference.Results: A total of 17 students participated (mean age 13.6 years, 11 girls). In the most demanding task (3-back) the following results were seen: improvement in reaction time following SRA (-30.1, p=0.04) and STEP (-34.3 ms, p=0.05) and no improvement following prolonged sitting. We also found a moderating effect (p <0.01)of WM performance at baseline (using a mean split), such that students with poor WM significantly improvedtheir accuracy and reaction time following the higher-intensity breaks (STEP) while students with highperformance did not.Conclusion: We found that implementing physical activity breaks of both moderate and high intensities wasbeneficial for WM performance. For students with low WM performance, high-intensity breaks were morebeneficial. Implementing physical activity breaks during periods of prolonged sitting, such as long schoolclasses could improve the students’ cognitive performance. However, future studies should investigate if thesebreaks are feasible, acceptable, and beneficial to implement in the school setting.

BACKGROUND: Physical activity breaks are widely being implemented in school settings as a solution to increase academic performance and reduce sitting time. However, the underlying physiological mechanisms suggested to improve cognitive function from physical activity and the frequency, intensity, and duration of the breaks remain unknown. This study will investigate the effects of frequent, short physical activity breaks during prolonged sitting on task-related prefrontal cerebral blood flow, cognitive performance, and psychological factors. Additionally, the moderating and mediating effects of arterial stiffness on changes in cerebral blood flow will be tested.

METHODS: This is a protocol for a randomized crossover study that will recruit 16 adolescents (13-14 years old). Participants will undergo three different conditions in a randomized order, on three separate days, involving sitting 80 min with a different type of break every 17 min for 3 min. The breaks will consist of (1) seated social breaks, (2) simple resistance activities, and (3) step-up activities. Before and after the 80-min conditions, prefrontal cerebral blood flow changes will be measured using functional near-infrared spectroscopy (primary outcome), while performing working memory tasks (1-, 2-, and 3-back tests). Arterial stiffness (augmentation index and pulse wave velocity) and psychological factors will also be assessed pre and post the 80-min interventions.

DISCUSSION: Publication of this protocol will help to increase rigor in science. The results will inform regarding the underlying mechanisms driving the association between physical activity breaks and cognitive performance. This information can be used for designing effective and feasible interventions to be implemented in schools.

TRIAL REGISTRATION: www.ClinicalTrials.gov , NCT04552626 . Retrospectively registered on September 21, 2020.

OBJECTIVES: To investigate the associations between physical activity pattern, sports participation, screen time and mental health in Swedish adolescents.

DESIGN, SETTING AND PARTICIPANTS: A total of 1139 Swedish adolescents (mean age 13.4) from 34 schools participated in the cross-sectional study 'Physical Activity for Healthy Brain Functions in School Youth' in 2019.

METHODS: Time spent sedentary and in moderate-to-vigorous physical activity (MVPA) was measured using accelerometers for seven consecutive days. Screen time and sports participation were self-reported. Anxiety and health-related quality of life (HRQoL) were assessed using a Short version of the Spence Children's Anxiety Scale and Kidscreen-10.

RESULTS: MVPA was positively associated (95% CI 0.01 to 0.05 in girls and 0.02 to 0.07 in boys) whereas screen time on weekdays was inversely associated with HRQoL (-4.79 to -2.22 in girls and -2.66 to -0.41 in boys). The largest effect sizes were observed between the high/low MVPA group in boys (Cohen's d=0.51) and screen time groups in girls (Cohen's d=0.59 on weekdays). With regards to anxiety, high compared with lower time spent in MVPA during leisure time on weekdays was associated with lower anxiety scores (95% CI -0.13 to -0.05 in girls and -0.07 to -0.01 in boys). Gender differences were observed, boys who participated in organised sports had low anxiety scores (95% CI -3.49 to -0.13) whereas girls who reported 5 hours or more of screen time had high scores (95% CI 1.94 to 6.18 on weekdays and 1.39 to 5.29 on weekend days).

CONCLUSIONS: This study showed that MVPA was associated with better mental health, whereas the opposite was seen for screen time. These associations were not consistently significant throughout all time domains, between the genders and mental health outcomes. Our results could create a paradigm for future studies to decide which types of PA patterns and time domains to target in intervention studies with the aim improve mental health among adolescents.

Most adolescents do not consume a high-quality diet, while self-reported mental health problems within this group are increasing. This study aimed to investigate the association between diet quality and health-related quality of life, and to explore the differences in diet quality and health-related quality of life between gender and parental education status. In this cross-sectional study, a detailed web-based recall method was implemented to determine dietary intake, which was analysed using the newly developed Swedish Healthy Eating Index for Adolescents 2015 (SHEIA15) and the Riksmaten Adolescents Diet Diversity Score (RADDS), to determine diet quality. The KIDSCREEN-10 questionnaire was used to measure health-related quality of life, and parental education was self-reported through questionnaires. Parental education was divided into two groups: ≤12 years or &gt;12 years. The study included 1139 adolescents from grade 7 (13-14 years old), 51% were girls. The results showed that girls had higher scores for healthy eating and diet diversity but lower scores for health-related quality of life. A positive association was found between diet diversity and health-related quality of life (Adj R² = 0.072, p = 0.001), between vegetable/fruit consumption and health-related quality of life (Adj R² = 0.071, p = 0.002), and between healthy eating and diet diversity (Adj R² = 0.214, p &lt; 0.001). No association was found between healthy eating and health-related quality of life for all participants. The mean scores for healthy eating and diet diversity were significantly higher in the higher education parental group. In conclusion, higher diet diversity and increased fruit and vegetable consumption could be a strategy to improve health-related quality of life among adolescents. There is a need to promote better diet quality, especially in households of low parental education. In addition, there is a further need to investigate the potential benefits of improved diet quality on mental health and overall well-being.

Background

The covid-19 pandemic has had a large impact on the daily lives of adolescents, even in Sweden where the restrictions were relatively mild. The aim of this study was to examine if there had been a change in mental health outcomes and if these changes were related to changes in physical activity patterns before and during the pandemic.

Methods

In this longitudinal study, data were collected in the autumn 2019 and in follow-up measurements in the spring 2021. Physical activity and sedentary time were measured for seven consecutive days by accelerometry (Actigraph). The mental health outcomes, health-related quality of life (HRQoL) and psychosomatic health were measured with questionnaires (KIDSCREEN-10 and PSP). ANCOVA analyses were applied to estimate the associations between change in physical activity patterns and mental health outcomes.

Results

In total, 585 boys (45%) and girls (55%), aged 13-14 years (baseline) from 34 schools around Stockholm, were included in the study. Between 2019-2021 there was a decrease in HRQoL (p > 0.001) and increase in psychosomatic problems (p > 0.001) among both boys and girls. There was a significant positive relationship between change in MVPA and change in HRQoL (β = 0.02, CI: 0.00, 0.05).

Conclusions

The results suggest that the COVID-19 pandemic has impaired the mental health of Swedish adolescents but increased physical activity was related to positive changes in the mental health outcome HRQoL.

Funding: The Public Health Authority and Skandia

Cardiovascular fitness (CVF) has been associated with cardiovascular risk factors in adolescents. CVF levels are determined by non-modifiable and modifiable factors; one modifiable factor is physical activity (PA). There is a lack of studies investigating the associations between PA patterns and CVF and how gender, parental education, BMI status and country of birth are associated with CVF. The aim of this study was to explore the cross-sectional associations between PA patterns and CVF in Swedish 13–14-year-old adolescents. CVF was estimated using the Ekblom-Bak submaximal test, data on PA patterns were collected using hip-worn accelerometers and a questionnaire. The mean CVF was 44.8 mL/kg/min in girls (n = 569) and 55.5 mL/kg/min in boys (n = 451) p < 0.01. The results showed a significant association between participation in organised sports (β = 3.32 CI: 2.14, 4.51, β = 4.38, CI: 2.80, 5.96), MVPA (β = 0.07, CI: 0.04, 0.11, β = 0.07, CI: 0.03, 0.11), a high proportion of SED (β = −0.47, CI: −0.70, −0.25, β = −0.41, CI: −0.64, −0.18) and CVF in girls and boys, respectively. More than five hours of screen time on weekdays was associated with lower CVF (β = −2.32 CI: −3.92, −0.71 in girls and boys β = −2.82, CI: −5.14, −0.50). While causal relations remain unknown, these findings could be relevant when designing future interventions with the aim to improve CVF.

Knowledge about associations between school-based initiatives and physical activity patterns is limited. The purpose of this paper was to examine associations between factors in the school environment, physical activity and sedentary time during school time. The cross-sectional study included 1139 adolescents aged 13–14 from 34 schools. Physical activity and sedentary time were measured using hip-worn accelerometers. Factors in the school environment included health policy, a mobile phone ban during breaks, organized physical activities during breaks and activity breaks during lessons reported by teachers. The frequency and duration of breaks and physical education (PE) lessons were collected from school schedules. The results showed significant associations between health policy (β = 3.87, 95% confidence interval (CI): 2.37, 5.23), the mobile phone ban (β = 2.51, 95% CI: 1.29, 3.94) and PE; total duration (β = 0.08, 95% CI: 0.05, 0.11), average duration (β = 0.08, 95% CI: 0.01, 0.13) and frequency (β = 1.73, 95% CI: 0.50, 3.04) and moderate-vigorous physical activity. There were negative associations between health policy (β = −6.41, 95% CI: −10.24, −2.67), the mobile phone ban (β = −3.75, 95% CI: −7.25, −0.77) and PE; total duration (β = −0.15, 95% CI: −0.23, −0.08) and average duration (β = −0.14, 95% CI: −0.27, −0.03) and time spent sedentary. Adolescents attending schools with health policies, mobile phone bans and more time for PE showed higher levels of physical activity and lower sedentary time.

This study explored whether breakfast habits were associated with intake of fruits and vegetables, minutes in moderate-to-vigorous physical activity (MVPA), minutes spent sedentary, and screen time among adolescents. Cross-sectional data were collected among 13&ndash;14-year-old boys and girls (n = 1139). Breakfast habits and screen time were determined via questionnaire, fruit and vegetable intake were determined through dietary recall, and physical activity and sedentary time were determined via accelerometers. Multilevel mixed models and general estimation equation models were applied. Almost 40% of participants skipped breakfast at least one day of the week. Participants with irregular breakfast habits on weekdays had lower fruit and vegetable consumption by 26.7 g (95% CI = &minus;49.3, &minus;5.9) while irregular breakfast habits during the whole week were associated with higher levels of screen time (OR = 1.5, 95% CI = 1.1, 2.1) compared to regular breakfast habits. Girls with irregular breakfast habits on weekdays had 7.7 min more sedentary time (95% CI = 0.8, 15.7) than girls with regular breakfast habits, while the opposite was found in boys (&beta; = &minus;13.3, 95% CI = &minus;25.3, &minus;2.6)). No significant associations were found for MVPA. Regular breakfast habits should be encouraged, as they might contribute to a higher intake of fruit and vegetables and are associated with lower levels of screen time, although further studies are necessary to establish causation.

AIM: The aim of this study was to investigate self-reported physical activity and sedentary behaviour by sex, age and parental education in a large representative sample of Swedish adolescents.

METHODS: This study is based on data from the national dietary survey Riksmaten Adolescents that was conducted by the Swedish Food Agency in 2016-2017. In total, 3477 students in grade five (11-12 years), eight (14-15 years), and eleven (17-18 years) were included. A web questionnaire was used to collect information about physical activity and sedentary behaviour.

RESULTS: In total, 53% reported active transport to and from school, 93% that they usually participate in the physical education, 76% reported a physically active leisure time, and 66% that they participated in organised physical activities. In addition, 12% and 6% reported two hours or less of screen time on weekdays and weekends, respectively. Participation in physical activity was generally lower among girls, older adolescents and for those from families with low parental education.

CONCLUSION: This study provide reference values for self-reported physical activities and sedentary behaviours among adolescents in Sweden. Strategies to increase physical activity and reduce screen time are needed, particularly among girls, older adolescents and among those with low parental education.

AIM: This study investigated objectively measured physical activity and sedentary time by sex, age and socioeconomic status in a large representative sample of Swedish adolescents.

METHODS: In this cross-sectional national survey between 2016 and 2017, students aged 11-12, 14-15 and 17-18 years from 131 schools were invited to participate. Physical activity and sedentary time were measured objectively with accelerometers for seven consecutive days. Socioeconomic status (parental education) and country of birth were self-reported in a questionnaire. Weight and height were measured by trained staff.

RESULTS: A total of 3477 adolescents participated in the study, and 2419 (73%) had at least 3 days of valid accelerometer data. The results showed that 43% of boys and 23% of girls reached the recommendation of 60 minutes of daily moderate-to-vigorous physical activity. Boys were more physically active than girls in all age groups. Girls with high socioeconomic status were more physically active than girls with low socioeconomic status (P < .001), and this difference was not found in boys.

CONCLUSION: The majority of Swedish adolescents did not reach the physical activity recommendation, and boys were more active than girls. Effective strategies to increase physical activity, especially among girls with low socioeconomic status, are urgently needed.

BACKGROUND: Dietary assessment methods that are user-friendly, simple, yet valid are of interest to both researchers and participants, particularly for use in disadvantaged settings, where language barriers and low levels of education are often present. We tested if parents taking photos of what children ate, using mobile phones, would be a feasible, acceptable method that could still provide information with adequate relative validity.

METHODS: We used a mixed-methods design, with parents of 21 5- to 7-year-olds from disadvantaged areas in Sweden. Parents reported all dietary intake, during non-school hours, on three days (two weekdays) using a photo method (PM). The PM consisted of simple instructions and a fiduciary card, but no training, equipment or software. Text messages could be sent if necessary. As a reference method, parents completed three 24-h recalls (24HRs) with an interviewer each following day. The next week, parents completed a 9-item semi-FFQ regarding the preceding week. The outcomes were intakes (in dl) of 9 food groups, categorised as fruits and vegetables, energy-dense sweet/salty foods, and sweet drinks. Agreement with the reference 24HRs was assessed using correlations, median differences and Bland-Altman plots. Parents completed an open-ended questionnaire on barriers and facilitators. Data collectors provided complementary information. Qualitative data was analysed using qualitative manifest analysis.

RESULTS: Nineteen parents (90%) provided complete data. The majority (n = 13) spoke Swedish as a second language, few (n = 4) were proficient. Compared to 24HRs, intakes measured by PM correlated well for all categories (Spearman's rho = 0.609-0.845). However, intakes were underreported, significantly so for fruits and vegetables; Bland-Altman plots indicated that the underestimation was fairly constant across intake levels. When the FFQ was compared to the 24HRs, parameters of agreement were generally inferior than for the PM. Parents found the PM a positive experience, primarily facilitated by its simplicity and familiarity. Barriers, mainly related to time and logistics, can inform further methodological refinements.

CONCLUSIONS: The PM was an acceptable and feasible way to measure children's diet outside of school hours in this population of parents from disadvantaged areas. While the absolute validity should be evaluated further, this relatively simple method has potential for assessing intakes of well-defined foods at group level.