Dr Jenna Hollis

© 2017 Macmillan Publishers Limited, part of Springer Nature. Background/Objectives:Pregnancy triggers a physiological change in weight status. Postpartum weight retention in the childbearing years can substantially alter a woman's weight gain trajectory, with several potential contributing factors identified. Most research has relied on women's recall of pre-pregnancy weight during pregnancy or later, and not considered risk factors in combination. Using measured pre-pregnancy weight, this study aimed to examine the associations of maternal postpartum weight retention with parity, pre-pregnancy BMI, excessive gestational weight gain (GWG), maternal serum vitamin D concentration and dietary Glycaemic Index in early and late pregnancy, and breastfeeding duration, including analysis of the combined impact of potentially modifiable risk factors.Subjects/Methods:Prospective cohort study of 12 583 non-pregnant women aged 20-34 years in Southampton (UK) who were assessed prior to pregnancy, with those who subsequently became pregnant followed up in early and late gestation, and after delivery (n=2559 in the final sample). Linear regression models examined potential predictors of weight retention in adjusted individual and multivariate analyses, and as a risk factor score.Results:Compared with pre-pregnancy weight, 73% of women retained some weight at 6 months postpartum (mean (s.d.): 3.5 (6.2) kg). In the adjusted multivariate model, women who were primiparous, had a lower pre-pregnancy BMI, excessive GWG, a lower early pregnancy vitamin D concentration and breastfed for <6 months had greater weight retention 6 months postpartum (P<0.05 for all variables). For each additional modifiable risk factor (excessive GWG, low vitamin D concentration in early pregnancy and short breastfeeding duration; scale 0-3), women retained an additional 2.49 kg (95% CI: 2.16, 2.82; P<0.001).Conclusions:Having a greater number of modifiable risk factors was associated with greater weight retention 6 months postpartum. Initiatives supporting women to target these risk factors in the years prior to, during and after pregnancy could impact on their weight gain trajectory and later risk of adverse weight-related outcomes.

© 2017 The Author(s). Background: Schools play an important role in physical activity promotion for adolescents. The systematic review aimed to determine the proportion of secondary (middle and high) school physical education (PE) lesson time that students spend in moderate to vigorous physical activity (MVPA), and to assess if MVPA was moderated by school level (middle and high school), type of physical activity measurement and type of PE activities. Methods: A systematic search of nine electronic databases was conducted (PROSPERO2014:CRD42014009649). Studies were eligible if they were published between 2005 and 2014; written in English; assessed MVPA in PE lessons of secondary (middle and high) school students; and used a quantitative MVPA measure (i.e., accelerometry, heart rate monitoring, pedometers or observational measures). Two reviewers examined the retrieved articles, assessed risk of bias, and performed data extraction. Random effects meta-analysis was used to calculate a pooled estimate of the percent of PE lesson time spent in MVPA and to assess moderator effects where data allowed. Results: The search yielded 5,132 potentially relevant articles; 28 articles representing 25 studies (7 middle and 18 high school) from seven countries were included. Twelve studies measured MVPA through observational measures, seven used accelerometers, five used heart rate monitors and four used pedometers (including three studies using a mix of measures). Meta-analysis of 15 studies found that overall, students spent a mean (95% CI) of 40.5% (34.8-46.2%) of PE in MVPA. Middle school students spent 48.6% (41.3-55.9%) of the lesson in MVPA (n=5 studies) and high school students 35.9% (28.3-43.6%) (n=10 studies). Studies measuring MVPA using accelerometers (n=5) showed that students spent 34.7% (25.1-44.4%) of the lesson in MVPA, while 44.4% (38.3-50.5%) was found for lessons assessed via observation (n=9), 43.1% (24.3-61.9%) of the lesson for a heart rate based study, and 35.9% (31.0-40.8%) for a pedometer-measured study. Conclusions: The proportion of PE spent in MVPA (40.5%) is below the US Centre for Disease Control and Prevention and the UK Associations for Physical Education recommendation of 50%. Findings differed according to the method of MVPA assessment. Additional strategies and intervention research are needed to build more active lesson time in PE.

© 2015 Elsevier Inc. Objective: To examine elementary school students' moderate-to-vigorous physical activity (MVPA) levels during physical education (PE) lessons. Methods: A systematic search of nine electronic databases was conducted (PROSPERO2014:CRD42014009649). Studies were eligible if they were in English; published between 2005-April 2014; assessed MVPA levels in PE lessons of elementary school children (aged four-12 years); and used an objective MVPA measure. Two reviewers retrieved articles, assessed risk of bias, and performed data extraction. The findings were synthesised using a meta-analysis. Results: The search yielded 5132 articles. Thirteen studies from nine countries met the inclusion criteria. Eight studies measured MVPA through observational measures, five used accelerometry and one used heart rate monitoring. The percentage of PE lesson time spent in MVPA ranged between 11.4-88.5%. Meta-analysis of seven studies (direct observations; 4 accelerometers) found that children spent a mean (95% CI) 44.8 (28.2-61.4)% of PE lesson time in MVPA. When measured using direct observation and accelerometers, children spent 57.6 (47.3-68.2) and 32.6 (5.9-59.3)% of PE lesson time in MVPA, respectively. The review has limitations; the search strategy was restricted to studies in English; theses, dissertations and conference abstracts were excluded; and six studies that provided insufficient data were excluded from the meta-analysis. Conclusion: MVPA levels during elementary school PE lessons do not meet the United States Centre for Disease Control and Prevention and the United Kingdom's Association of Physical Education recommendation (50% of lesson time), but is higher than estimated in the previous review (34.2%). Interventions to increase MVPA in PE lessons are needed.

Background: Adolescence is a recognised period of physical activity decline, particularly among low-income communities. We report the 12-month (midpoint) effects of a 2-year multicomponent physical activity intervention implemented in disadvantaged secondary schools. Methods: A cluster randomised trial was undertaken in 10 secondary schools located in disadvantaged areas in New South Wales, Australia. Students in Grade 7 were recruited, with follow-up in Grade 8. The intervention was guided by socioecological theory and included seven physical activity strategies, and six implementation adoption strategies. The primary outcome was mean minutes of moderate-to-vigorous physical activity (MVPA) per day assessed using Actigraph GT3X accelerometers. Outcome data were analysed using repeated measures linear mixed models. Results: At baseline, 1150 (93%) students participated in the data collection (mean age 12 years, 48% boys) and 1050 (79%) students participated at 12-month follow-up. By the 12-month follow-up, the six implementation adoption strategies had been used to support schools to deliver four of the seven physical activity elements. There was a significant group-by-time interaction for mean minutes of MVPA per day in favour of the intervention group (adjusted difference between groups at follow-up=3.85 min, 95% CI (0.79 to 6.91), p=0.01), including significantly more vigorous physical activity (2.45 min, p=0.01), equating to 27 min more MVPA per week. Summary: At 12-month follow-up, the intervention had reduced the decline in physical activity among adolescents from disadvantaged schools. The intervention may assist students to meet physical activity guidelines.

© 2015 Dietitians Association of Australia. Aim: The 40-Something Randomised Controlled Trial (RCT) aimed to determine if a 12-month health professional-led intervention could improve dietary intake and increase physical activity for weight gain prevention in non-obese premenopausal women. Methods: Fifty-four women were randomised to a motivational interviewing intervention (MI) (n = 28; five health professional consultations) or a self-directed intervention (SDI; n = 26; written advice). Weight control behaviours including dietary intake (four-day weighed food record) and physical activity (pedometer steps; minutes spent in light, moderate and vigorous activity; sitting time) were measured at baseline, and at 3 and 12 months. Participants completed a questionnaire containing demographic questions, Short Form 36 and the International Physical Activity Questionnaire at baseline and 12 months. Linear mixed model analyses adjusting for baseline and 3-month behaviour, covariates and interactions were used to test for between-group differences. Results: At 12 months, the MI group had diets significantly more nutrient dense in iron (P = 0.01) and potassium (P = 0.04), and consumed more fruits (P = 0.02) than the SDI women. Women who achieved their weight control goals consumed significantly more daily fruit servings (+0.76 servings/day, P = 0.02) and less meat/meat alternatives (-0.34 servings/day, P < 0.01) than women who did not achieve weight control. The lack of changes in physical activity indicates that more emphasis may need to be placed on promoting physical activity. Conclusions: The findings demonstrated the effectiveness of the 40-Something RCT in improving iron and potassium nutrient density and fruit servings per day in women soon to commence menopause.