Paola Chivers

Body mass index, adiposity rebound and early feeding in a longitudinal cohort (Raine Study).

Objective:This study examined the influence of type and duration of infant feeding on adiposity rebound and the tracking of body mass index (BMI) from birth to 14 years of age.Methods:A sample of 1330 individuals over eight follows-ups was drawn from the Western Australian Pregnancy Cohort (Raine) Study. Trajectories of BMI from birth to adolescence using linear mixed model analysis investigated the influence of age at which breastfeeding was stopped and the age at which other milk was introduced (binomial 4-month cutoff point). A subsample of linear mixed model-predicted BMI was used to determine BMI and age at nadir for early infant feeding groups.Results:Chi-square analysis between early feeding and weight status (normal weight, overweight and obese) groups found a significant difference between thee age at which breastfeeding was stopped (P<0.001) and the age at which other milk was introduced (P=0.011), with a higher proportion of overweight and obese in the ⩽4-month group, even after controlling for maternal education. Using the linear mixed model, the BMI determined was higher over time for the group that was breastfed for ⩽4 months (P=0.015), with a significant interaction effect with the group in which other milk was introduced at ⩽4 months (P=0.011). Using predicted BMI from the linear mixed model, significant differences for nadirs of adiposity rebound between early feeding groups were found (P<0.005).Conclusions:Early infant feeding was important in the timing of, and BMI at, adiposity rebound. The relationship between infant feeding and BMI remained up to the age of 14 years. Although confounding factors cannot be excluded, these findings support the importance of exclusive breastfeeding for longer than 4 months as a protective behaviour against the development of adolescent obesity.

The associations between physical activity, screen time and weight from 6 to 14 yrs: the Raine Study.

To examine the strength and direction of the relationship between physical activity level, screen use and BMI in a cohort at ages 6, 8, 10 and 14 yrs as part of a prospective longitudinal cohort study. The sample comprised 1403 males and females who participated in the follow-up survey at 14 yrs of age between 2003 and 2005. Exploratory structural equation modelling was used to examine the interrelationships between physical activity level, BMI and screen time at 6, 8, 10 and 14 yrs. Predictors of BMI at 6, 8, 10 and 14 yrs explained 1.3, 76.1, 80.1 and 73.1 percent of the variances, respectively, with previous BMI the largest predictor [χ(2)=43.082, df=36, p=194]. Increased screen time predicted higher BMI and lower physical activity at 8 and 10 yrs but not 14 yrs. At 14 yrs, physical activity predicted BMI. Sedentary patterns of behaviour in early childhood were predictive of later and concurrent obesity, whereas physical activity was predictive of obesity in adolescence. Different intervention targets are required for children and adolescents.

Early infant feeding and adiposity risk: from infancy to adulthood

Introduction: Systematic reviews suggest that a longer duration of breast-feeding is associated with a reduction in the risk of later overweight and obesity. Most studies examining breast-feeding in relation to adiposity have not used longitudinal analysis. In our study, we aimed to examine early infant feeding and adiposity risk in a longitudinal cohort from birth to young adulthood using new as well as published data. Methods: Data from the Western Australian Pregnancy Cohort (Raine) Study in Perth, W.A., Australia, were used to examine associations between breast-feeding and measures of adiposity at 1, 2, 3, 6, 8, 10, 14, 17, and 20 years. Results: Breast-feeding was measured in a number of ways. Longer breast-feeding (in months) was associated with reductions in weight z-scores between birth and 1 year (β = -0.027; p < 0.001) in the adjusted analysis. At 3 years, breast-feeding for <4 months increased the odds of infants experiencing early rapid growth (OR 2.05; 95% CI 1.43-2.94; p < 0.001). From 1 to 8 years, children breast-fed for ≤4 months compared to ≥12 months had a significantly greater probability of exceeding the 95th percentile of weight. The age at which breast-feeding was stopped and a milk other than breast milk was introduced (introduction of formula milk) played a significant role in the trajectory of the BMI from birth to 14 years; the 4-month cutoff point was consistently associated with a higher BMI trajectory. Introduction of a milk other than breast milk before 6 months compared to at 6 months or later was a risk factor for being overweight or obese at 20 years of age (OR 1.47; 95% CI 1.12-1.93; p = 0.005). Discussion: Breast-feeding until 6 months of age and beyond should be encouraged and is recommended for protection against increased adiposity in childhood, adolescence, and young adulthood. Adverse long-term effects of early growth acceleration are fundamental in later overweight and obesity. Formula feeding stimulates a higher postnatal growth velocity, whereas breast-feeding promotes slower growth and a reduced likelihood of overweight and obesity. Biological mechanisms underlying the protective effect of breast-feeding against obesity are based on the unique composition and metabolic and physiological responses to human milk.

Longitudinal Modelling of Body Mass Index from Birth to 14 Years

Background: To examine the tracking of BMI from birth to age 14 years. Participants and Methods: Linear mixed model (LMM) analysis was used to model the trajectories of BMI (n = 1,403). Adiposity rebound was investigated for a subset of individuals (n = 173). Results: Adolescents who were overweight or obese at 14 years followed a different BMI trajectory from birth compared to those of normal weight. There was a difference between weight status groups for the timing of adiposity rebound (p < 0.001) and BMI at nadir (p < 0.001). The LMM depicted a significant difference in rate of change of BMI over time for males and females (p < 0.001), with female BMI increasing at a faster rate, and for weight status groups (p < 0.005), with the obese cohort having the faster increase in BMI over time. BMI at birth was significantly lower for the normal weight cohort compared to the overweight (p = 0.029) and obese (p = 0.019) cohorts. Conclusion: This study introduces a powerful analytic tool, LMM, to model BMI and shows that weight status at 14 years is the result of a distinct path in earlier years. Compared to their normal weight peers, overweight and obese adolescents experience an earlier adiposity rebound, with a higher BMI at rebound.

Exercise can improve physical self perceptions in adolescents with low motor competence

Adolescents with low motor competence have diminished perceptions of their physical self and tend to avoid physical activities. This study examined the outcomes of an exercise intervention that focused on improving aerobic fitness, strength, and self-perceptions in the physical domain in adolescents with poor motor coordination. The sample included 35 adolescents with low motor competence, comprising boys (n = 25) and girls (n = 10) ranging in age from 13 to 17 years, who attended two sessions per week in the 13 week exercise intervention study (AMP it up). Physical self-perceptions were measured before and after the intervention using the Physical Self Perception Profile and Perceived Importance Profile. Significant improvements in perceived Physical Condition, Attractive Body and Physical Strength sub domain scores were identified between pre and post-test. Adjusting for age, gender, BMI and attendance, regression analyses revealed that Attractive Body was the strongest predictor of Physical Self Worth at pre-test, joined by Physical Condition at post-test. This exercise intervention had a positive impact on adolescent physical self-perceptions, in particular males, with improvements in those sub domains specifically related to the exercise program. Changes in specific aspects of Physical Self Worth can be facilitated by exercise interventions, after a relatively short period of time, in adolescents with poor motor coordination.

Parental and early childhood influences on adolescent obesity: A longitudinal study

The influence of parental and early childhood factors on adolescent obesity was investigated using a longitudinal model of body mass index (BMI) from birth to 14 years. Trajectories of BMI using linear mixed model (LMM) analysis were used to investigate the influence of early parental and childhood factors on BMI at 14 years in the Raine birth cohort study over eight follow-ups (n = 1403). An inverse relationship between parental education attainment and BMI was found (mothers χ 2 = 21.75, p = 0.016; LMM p = 0.043; fathers χ 2 = 21.19, p = 0.020; LMM p > 0.05). More overweight adolescents had mothers who smoked during pregnancy (χ 2 = 12.60, p = 0.002). Parental birth weight and BMI across years (p < 0.001) were strongly associated with adolescent obesity (LMM p < 0.05). Obese adolescents visited the park or playground infrequently as toddlers (p < 0.05). Results for early home environment factors were mixed. Maternal education, parental birth weight, and parental BMI were the strongest influences on their childs BMI from birth to adolescence.

Low motor performance scores among overweight children: poor coordination or morphological constraints?

This study examined whether lower motor performance scores can be full attributed to poor coordination, or whether weight related morphological constraints may also affect motor performance. Data for 666 children and adolescents from the longitudinal Western Australian Pregnancy Cohort (Raine) Study were grouped into normal weight, overweight and obese categories based on the International Obesity Task Force cut points. Participants completed the 10-item McCarron Assessment of Neuromuscular Development (MAND) at the 10 and 14 year follow-up. The prevalence of overweight and obese participants classified with mild or moderate motor difficulties was not different from the normal weight group at 10 years (χ2 = 5.8 p = .215), but higher at 14 years (χ2 = 11.3 p = .023). There were no significant differences in overall motor performance scores between weight status groups at 10 years, but at 14 years, the normal weight group achieved better scores than the obese group (p<.05). For specific items, the normal weight group consistently scored higher than the overweight and obese groups on the jump task at 10 (p<.001) and 14 (p<.01)years but lower on the hand strength task at both ages (p<.01). Our findings raise the question as to whether some test items commonly used for assessing motor competence are appropriate for an increasingly overweight and obese population.

Randomised controlled trial comparing daily VerSus depot vitamin D3 therapy in 0-16-year-old newly settled refugees in Western Australia over a period of 40 weeks

Vitamin D deficiency is highly prevalent in newly settled refugees in Western Australia (WA). If adherence to daily vitamin D therapy is problematic, depot therapy is a therapeutic alternative. The aim of this study was to compare daily versus depot treatment and factors influencing the therapeutic outcome. Newly settled refugees (n = 151) with 25(OH)D levels less than 78 nmol/L were randomised to receive daily or depot vitamin D therapy with eight weekly interval follow up to 40 weeks. Biochemical and clinical parameters were collected at each visit. Generalized Linear Mixed Models (GLMM) examined the longitudinal changes over time controlling for confounders including age, gender, treatment arm, season, country of refuge/origin and sun exposure score. Participants were aged 5.5 months to 16.0 years (75 males, 83 females). Both treatment groups achieved vitamin D sufficiency. The daily treatment group had significantly higher 25(OH)D levels at each visit post baseline and a higher proportion of participants with levels above 50 nmol/L at all time points. Time, treatment group, calcium and sun exposure score were significant predictors of 25(OH)D serum levels. Depot vitamin D therapy is an alternative to daily treatment in this at-risk group of children and adolescents in whom treatment adherence is problematic.

Don't know, don't care or confused: what do Australian adolescents know about Australian Dietary Guidelines?

ABSTRACT Western Australian adolescents are not adhering to the Australian Dietary Guidelines yet little research has considered what adolescents know about the Healthy Living Pyramid (HLP), the recommended daily serves. Four studies assessed nutrition-related knowledge or influences on food preference. Studies one and two investigated adolescents perceptions of healthy and unhealthy food and what influences their food choice by conducting 24 gender-specific focus groups (n = 150, 12–16 years). Study three (n = 28, 13–14 year) assessed the test–retest reliability of a nutrition questionnaire that measured knowledge of the HLP and the recommended daily serves. Study four (n = 38, 12–16 years) measured changes in HLP knowledge after a six session community-based cooking and food-literacy program. Participants knowledge about discretionary foods and vegetables was high, however, knowledge about intake of the other food groups especially grains was poor. Body image emerged as the strongest influence over food preference with media reinforcing girls desire to be thin and boys desire to be muscular.

Advanced Training of Gynecologic Surgeons and Incidence of Intraoperative Complications after Total Laparoscopic Hysterectomy: a Retrospective Study of More Than 2000 Cases at a Single Institution

STUDY OBJECTIVE To investigate whether surgeon factors including level of training undertaken in laparoscopic surgery, time in specialist practice, and case volume were associated with surgical morbidity for total laparoscopic hysterectomy (TLH). DESIGN A retrospective cohort study (Canadian Task Force classification II-2). SETTING A tertiary care setting in Western Australia. PATIENTS Two thousand thirteen patients who underwent TLH for benign or malignant indications. INTERVENTIONS Women undergoing TLH were allocated to 1 of 3 groups of surgeons: general gynecologists, gynecologic endoscopists, and subspecialists. MEASUREMENTS AND MAIN RESULTS All patients undergoing elective TLH at St John of God Subiaco Hospital, Subiaco, Perth, Western Australia, between January 1, 2011, and December 31, 2016, were included for analysis. Variables recorded included cystotomy, ureteric injury, enterotomy/colostomy, bowel serosa injury, vascular injury, conversion to laparotomy, return to the operating room, hemorrhage, blood transfusion, operating time, length of stay, and postoperative complications to 42 days. The primary outcome was any major intraoperative complication. The incidence of any major intraoperative complication was 1.8% (36/2013 cases). Forty-five patients (2.2%) had a postoperative complication, and 74 (3.7%) patients were readmitted to the hospital after discharge. The incidence of any major intraoperative complication was significantly higher among general gynecologists compared with subspecialists (3.3% vs 1.1%, p = .002). No association was found between time in specialist practice and the incidence of major intraoperative complications (p = .629). A significant association for major intraoperative complications was observed for surgeons who had performed <100 laparoscopic hysterectomies during the study period (p = .032). CONCLUSION In this study, despite a higher level of surgical acuity and the performance of additional and more complex procedures, surgical morbidity was lower in patients undergoing TLH by gynecologic surgeons with a higher level of subspecialist training.