Effectiveness of the Walking in ScHools (WISH) Study, a peer-led walking intervention for adolescent girls: results of a cluster randomised controlled trial.

BACKGROUND: Most adolescent girls fail to meet current physical activity guidelines. Physical activity behaviours track from childhood into adulthood and providing adolescent girls with opportunities to be physically active may have health benefits beyond childhood. The effects of walking interventions on adult cardiometabolic health are known, however less is understood about the potential of walking to promote physical activity in adolescents. Following the Walking In ScHools (WISH) feasibility study, this definitive trial aimed to evaluate the effectiveness of a novel, low-cost, school-based walking intervention at increasing physical activity levels of adolescent girls (aged 12-14 years). METHODS: Female pupils were recruited from eighteen schools across the border region of Ireland and in Northern Ireland. In intervention schools (n = 9), girls aged 15-18 years, were trained as walk leaders, and led the younger pupils in 10-15 min walks before school, at break and lunch recess. All walks took place in school grounds and pupils were encouraged to participate in as many walks as possible each week. The primary outcome measure was accelerometer determined total physical activity (counts per minutes, cpm). RESULTS: In total, 589 pupils were recruited to the study. At baseline, pupils engaged in a median (interquartile range (IQR)) 35.7 (21.2) mins moderate-vigorous physical activity (MVPA) per day and only 12% (n = 66) of participants met physical activity guidelines (60 min MVPA per day). The intervention was delivered for a mean (standard deviation (SD)) 19.9 ± 0.97 weeks. The mean post-intervention total physical activity for the intervention group was 676 cpm and 710 cpm in the control group. Post-intervention total physical activity did not statistically differ between groups when adjusted for age, body mass index z-scores and baseline physical activity (mean difference, -33.5, 95% CI = -21.2 to 88.1; p = 0.213). CONCLUSIONS: 'Scaling-up' physical activity interventions is challenging and despite a promising feasibility study, the results of this fully powered trial suggest that in this context, the WISH intervention did not increase device measured physical activity. Since the COVID-19 pandemic, school environments have changed and although pupils enjoyed the programme, attendance at walks was low, indicating that there is a need to better understand how to implement interventions within schools. TRIAL REGISTRATION: ISRCTN; ISRCTN12847782; Registered 2nd July 2019.

A peer-led walking intervention for adolescent girls (the WISH study): a cluster-randomised controlled trial.

BACKGROUND: Adolescent girls in the UK and Ireland fail to meet physical activity (PA) guidelines. PA behaviours track from childhood into adulthood. The effects of walking interventions on adult health are known; however, the potential of walking to promote PA in adolescents is less known. This study evaluated the effectiveness of a novel, school-based walking intervention aimed at increasing PA levels of adolescent girls. METHODS: In this cluster-randomised controlled trial, female pupils aged 12-14 years were recruited from 18 (mixed or single-sex) schools across the border region of Ireland and Northern Ireland. Schools were randomly assigned to either the control group (usual physical activity; n=9) or the intervention group (n=9) by independent faculty staff using an online randomisation tool (randomization.com). In intervention schools, female pupils aged 15-18 years were trained as walk leaders and led the younger pupils in 10-15 min walks before school, at break, and at lunchtime. Walks were in school grounds and pupils were encouraged to join as many walks as possible. The intervention was delivered for a full school year excluding holidays (for a total of 18-21 weeks). Accelerometers measured PA, and the primary outcome was total PA (counts per minute [cpm]). Ethics approval was granted by Ulster University Research Ethics Committee and written informed consent (parent or guardian) and assent (pupils) was obtained. This study is registered with the ISRCTN Registry, 12847782. FINDINGS: The study took place from Sept 1, 2021, to May 31, 2023. In total, 589 pupils were recruited (n=286 in intervention group; n=303 in control group). Median moderate-vigorous PA (MVPA) at baseline was 36·1 min/day (IQR 23·0) for the intervention group and 35·3 min/day (19·8) for the control group. Only 37 (15%) girls in the intervention group and 29 (10%) girls in the control group met PA guidelines (60 min/day of MVPA). The mean total PA after intervention was 676 cpm (SD 18·7) for the intervention group and 710 cpm (SD 17·7) for the control group. Post-intervention total PA did not differ between groups when adjusted for age, body-mass index, z-scores, and baseline PA (mean difference -33·5, 95% CI -21·2 to 88·1; p=0·213). INTERPRETATION: Scaling up PA interventions is challenging. Despite a promising feasibility study, the results of this fully powered trial indicate that in this context, the walking programme did not increase PA. Since the COVID-19 pandemic, school environments have changed, and although pupils enjoyed the programme, attendance at walks was low. There is a need to better understand the implementation of interventions such as this within schools. FUNDING: Cross-border Healthcare Intervention Trials in Ireland Network (CHITIN).

Changes in Physical Activity, Sleep, Mental Health, and Social Media Use During COVID-19 Lockdown Among Adolescent Girls: A Mixed-Methods Study.

BACKGROUND: To suppress the transmission of coronavirus, many governments, including that of the island of Ireland, implemented a societal lockdown, which included school closures, limits on social gatherings, and time outdoors. This study aimed to evaluate changes in physical activity (PA), mental health, sleep, and social media use among adolescent girls during lockdown. METHODS: 281 female pupils (12-14 y) taking part in the ongoing Walking In Schools study on the island of Ireland self-reported PA, mental health, sleep, and social media use before (September-October 2019) and during lockdown (May-June 2020), via questionnaires. These were supplemented with open-ended structured interviews conducted with 16 girls during lockdown. RESULTS: During the period of lockdown and school closures, pupils tried new forms of PA and undertook PA with family, but there was no significant change in self-reported PA. There was a decline in health-related quality of life and motivation for exercise; however, self-efficacy for walking and happiness with appearance increased. There was no change in sleep quality or social media usage. CONCLUSIONS: Despite the many challenges that schools face as they reopen, there is a need to continue to prioritize PA and motivation for exercise to support health and well-being in adolescent girls.

A study protocol for a clustered randomised controlled trial to evaluate the effectiveness of a peer-led school-based walking intervention on adolescent girls' physical activity: the Walking In ScHools (WISH) study.

BACKGROUND: Adolescent girls in the UK and Ireland are failing to meet current physical activity guidelines. Physical activity behaviours track from childhood to adulthood and it is important that adolescent girls are provided with opportunities to be physically active. Walking has been a central focus for physical activity promotion in adults and may effectively increase physical activity levels among younger people. Following on from a pilot feasibility trial, the purpose of this cluster randomised controlled trial (c-RCT) is to evaluate the effectiveness of a novel, low-cost, peer-led school-based walking intervention delivered across the school year at increasing physical activity levels of adolescent girls. METHODS: The Walking In ScHools (WISH) Study is a school-based c-RCT conducted with girls aged 12-14 years from eighteen schools across the Border Region of Ireland / Northern Ireland. Following baseline data collection, schools will be randomly allocated to intervention or control group. In intervention schools, female pupils aged 15-18 years will be invited to train as walk leaders and will lead younger pupils in 10-15 min walks before school, at break and lunch recess. All walks will take place in school grounds and pupils will be encouraged to participate in as many walks as possible each week. The intervention will be delivered for the whole school year (minimum 20-22 weeks). The primary outcome measure is accelerometer-measured total physical activity (counts per minute) (end of intervention). Secondary outcomes will include time spent in sedentary behaviour, light, moderate and vigorous intensity physical activity, anthropometry measures, social media usage and sleep. A mixed-methods process evaluation will also be undertaken. DISCUSSION: The WISH Study will examine the effectiveness of a low-cost, school-based, peer-led walking intervention in increasing physical activity in adolescent girls when delivered across the school year. If the intervention increases physical activity, it would benefit adolescent girls in the defined target area with potential for wider adoption by schools across the UK and Ireland. TRIAL REGISTRATION: ISRCTN; ISRCTN12847782; Registered 2nd July 2019.

Cow Milk Consumption Increases Iodine Status in Women of Childbearing Age in a Randomized Controlled Trial.

Background: Recent evidence has highlighted the prevalence of mild-to-moderate iodine deficiency in women of childbearing age and pregnant women, with important public health ramifications due to the role of iodine, which is required for thyroid hormone production, in neurodevelopment. Cow milk contributes the greatest amount to iodine intakes in several countries. Objective: The objective of this study was to investigate the effect of increased cow milk consumption on iodine status, thyroid hormone concentrations, and selenium status. Methods: A 12-wk randomized controlled trial was conducted in 78 low-moderate milk-consuming (<250 mL/d) healthy women (aged 18-45 y). The intervention group was asked to consume 3 L semiskimmed milk/wk, whereas the control group continued their usual milk consumption (baseline median: 140 mL/d; IQR: 40-240 mL/d). At baseline and weeks 6 and 12, participants provided a spot urine sample [urinary iodine concentration (UIC), creatinine] and a fasting blood sample (thyroid hormone concentrations, serum total selenium, selenoprotein P). Results: At baseline, the median (IQR) UIC of all participants was 78.5 µg/L (39.1-126.1 µg/L). Changes in the median UIC from baseline to week 6 (35.4 compared with 0.6 µg/L; P = 0.014) and week 12 (51.6 compared with -3.8 µg/L; P = 0.045) were significantly greater in the intervention group compared with the control group. However, despite being higher within the intervention group at weeks 6 and 12, the change in the iodine:creatinine ratio from baseline was not significantly different between groups at either week 6 (P = 0.637) or week 12 (P = 0.178). There were no significant differences in thyroid hormone concentrations or selenium status between groups at any time point. Conclusions: The present study shows that the consumption of additional cow milk can significantly increase UIC in women of childbearing age. These results suggest that cow milk is a potentially important dietary source of iodine in this population group. This trial was registered at www.clinicaltrials.gov as NCT02767167.

The Effect of Processing and Seasonality on the Iodine and Selenium Concentration of Cow's Milk Produced in Northern Ireland (NI): Implications for Population Dietary Intake.

Cow's milk is the most important dietary source of iodine in the UK and Ireland, and also contributes to dietary selenium intakes. The aim of this study was to investigate the effect of season, milk fat class (whole; semi-skimmed; skimmed) and pasteurisation on iodine and selenium concentrations in Northern Ireland (NI) milk, and to estimate the contribution of this milk to consumer iodine and selenium intakes. Milk samples (unpasteurised, whole, semi-skimmed and skimmed) were collected weekly from two large NI creameries between May 2013 and April 2014 and were analysed by inductively coupled plasma-mass spectrometry (ICP-MS). Using milk consumption data from the National Diet and Nutrition Survey (NDNS) Rolling Programme, the contribution of milk (at iodine and selenium concentrations measured in the present study) to UK dietary intakes was estimated. The mean ± standard deviation (SD) iodine concentration of milk was 475.9 ± 63.5 µg/kg and the mean selenium concentration of milk was 17.8 ± 2.7 µg/kg. Season had an important determining effect on the iodine, but not the selenium, content of cow's milk, where iodine concentrations were highest in milk produced in spring compared to autumn months (534.3 ± 53.7 vs. 433.6 ± 57.8 µg/kg, respectively; p = 0.001). The measured iodine and selenium concentrations of NI milk were higher than those listed in current UK Food Composition Databases (Food Standards Agency (FSA) (2002); FSA (2015)). The dietary modelling analysis confirmed that milk makes an important contribution to iodine and selenium intakes. This contribution may be higher than previously estimated if iodine and selenium (+25.0 and +1.1 µg/day respectively) concentrations measured in the present study were replicable across the UK at the current level of milk consumption. Iodine intakes were theoretically shown to vary by season concurrent with the seasonal variation in NI milk iodine concentrations. Routine monitoring of milk iodine concentrations is required and efforts should be made to understand reasons for fluctuations in milk iodine concentrations, in order to realise the nutritional impact to consumers.

Micronutrients, iodine status and concentrations of thyroid hormones: a systematic review.

Context: The metabolism of thyroid hormones, which are essential for normal development, involves many proteins and enzymes. It requires iodine as a key component but is also influenced by several other micronutrients, including selenium, zinc, iron, and vitamin A. Objective: This systematic review was designed to investigate the effect of micronutrient status and supplementation on iodine status and thyroid hormone concentrations. Data Sources: Using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines, electronic databases were searched from their inception to April 2016. Study Selection: Human studies published in English and reporting data on micronutrient status and iodine status and/or thyroid hormone concentrations were included. Studies that examined the effect of micronutrient supplementation on iodine status and/or thyroid hormone concentrations were also included. Data Extraction: A predesigned and piloted data extraction form was used to compile data from individual studies. Results: A total of 57 studies were included: 20 intervention studies and 37 observational studies. Although observational evidence suggests that concentrations of selenium, zinc, and iron are positively associated with iodine status, data from randomized controlled trials fail to confirm this relationship. Conclusions: Further studies are needed to provide greater understanding of the role of micronutrient status in iodine nutrition and thyroid function to ascertain the public health implications for populations worldwide.

Iodine knowledge is positively associated with dietary iodine intake among women of childbearing age in the UK and Ireland.

Adequate I intake is important before conception and during pregnancy for optimal infant neurodevelopment. Recent studies have highlighted the prevalence of I deficiency in the UK and Ireland. It is possible that optimal I intake may be impeded by a poor knowledge of I nutrition. This study aimed to investigate I knowledge among women of childbearing age in the UK and Ireland and to determine whether a relationship exists between I knowledge and dietary I intake. Females (aged 18-45 years) were invited to complete an online questionnaire, which assessed knowledge of I and estimated dietary I intake using a FFQ. A total of 520 females of childbearing age completed the study. I knowledge was poor; only one-third (32 %) of the participants correctly identified pregnancy as the most important stage of the lifecycle for I, and 41 % of participants could not correctly identify any health problem related to I deficiency. The median daily I intake was estimated as 152 µg/d. Almost half (46 %) of the participants failed to meet dietary recommendations (140 µg/d) for I. A higher dietary I intake was positively associated with greater I knowledge (r 0·107; P=0·016). This study suggests that knowledge of I nutrition is low among women of childbearing age, and those with a greater knowledge of I nutrition had a higher dietary I intake. Initiatives to educate women of childbearing age on the importance of I nutrition should be considered as part of a larger public health strategy to address I deficiency.