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"Downing, Jill"
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Preclinical Left Ventricular Diastolic Dysfunction in Metabolic Syndrome
by
Colucci, Wilson S.
,
Mooney, Deirdre M.
,
Downing, Jill
in
Adult
,
Body mass index
,
Cardiovascular
2014
Metabolic syndrome (MS) is commonly associated with left ventricular (LV) diastolic dysfunction and LV hypertrophy. We sought to examine whether preclinical LV diastolic dysfunction can occur independent of LV hypertrophy in MS. We recruited 90 consecutive participants with MS and without cardiovascular disease (mean age 46 years, 78% women) and 26 controls (no risk factors for MS; mean age 43 years, 65% women). Participants underwent echocardiography with tissue Doppler imaging. In age- and gender-adjusted analyses, MS was associated with higher left atrial (LA) diameter, higher LV mass, lower E/A ratio, and lower mean e′ (p <0.001 for all). These associations remained significant after further adjusting for blood pressure, antihypertensive medication use, and body mass index. After adjusting for LV mass, MS remained independently associated with higher LA diameter, lower E/A ratio, and lower mean e′ (p ≤0.01 for all). Specifically, subjects with MS had a 1.8 cm/s lower mean e′ compared with controls (p = 0.01). Notably, differences in mean e′ between those with and without MS were more pronounced at younger ages (p for interaction = 0.003). In conclusion, MS was associated with preclinical LV diastolic dysfunction independent of LV mass, as reflected by higher LA diameter, lower E/A ratio, and lower mean e′. This suggests that MS can lead to the development of diastolic dysfunction through mechanisms independent of hypertrophy. Differences in diastolic function were more pronounced at younger ages, highlighting the potential importance of early risk factor modification and preventive strategies in MS.
Journal Article
Assessing the Safety of Anthrax Immunization in US Army Aircrew Members via Physical Examination
2007
Objective: Anthrax in weaponized form is the bioterrorism agent of most concern. Questions raised about the safety of the anthrax vaccine can be addressed by comparing immunized and unimmunized people in population-based studies. Methods: A retrospective evaluation of data from periodic physical examinations collected on anthraximmunized and -unimmunized US Army aircrew members between 1998 and 2005 was performed to evaluate the safety of anthrax immunization. Mean changes in variables found on physical examination and laboratory analysis were compared by use oft tests. Multiple linear regression predicted change in outcome from baseline characteristics. Results: We compared 6820 immunized subjects and 4145 unimmunized controls based on US Army aircrew physical examination and screening laboratory tests. No association between anthrax immunization and a clinically relevant change in a tested physiologic parameter was detected. Conclusions: No attributable risk of anthrax immunization was observed in this group of Army aircrew members.
Journal Article
Pupil Preferences and the Premack Principle
by
Gentile, J. Ronald
,
Hosie, Thomas W.
,
Carroll, Jill Downing
in
Candies
,
Classroom observations
,
Dinosaurs
1974
Journal Article
Do the correlates of screen time and sedentary time differ in preschool children?
2017
Background
Preschool children can spend up to 12 h a day in sedentary time and few meet current recommendations for screen time. Little is known about ecological correlates that could be targeted to decrease specific versus total sedentary behaviour. This study examined whether the correlates of screen time and sedentary time differ in preschool boys and girls.
Methods
Parents participating in the HAPPY Study in 2008/09 in Melbourne, Australia reported their child’s usual screen time and potential individual, social and physical environment correlates. Children wore ActiGraph GT1M accelerometers for eight days to objectively assess sedentary time (<100 counts.min
−1
). Multivariable linear regression analyses were performed, stratified by sex and controlling for child age, preschool/childcare attendance and clustering by centre of recruitment. Correlates significantly associated with screen time or sedentary time in individual models (
p
< 0.05) were included in final combined models.
Results
Children were sedentary for 301.1 (SD 34.1) minutes/day and spent 108.5 (SD 69.6) minutes/day in screen time. There were no sex differences in screen or sedentary time. In the final models, sleep duration was inversely associated with girls’ sedentary time and boys’ screen time. The only other consistent correlates for boys and girls were parental self-efficacy to limit screen time and screen time rules, which were inversely associated with screen time for both sexes. Parents reporting that they get bored watching their child play was inversely associated and maternal television viewing was positively associated with boys’ screen time. Paternal age was positively associated with boys’ sedentary time. Maternal ethnicity was inversely associated and paternal education, child preferences for sedentary behaviour, and parental concerns about child’s physical activity and sedentary behaviour were positively associated with girls’ screen time.
Conclusions
The modifiable correlates of total sedentary and screen time identified in this study could be targeted in interventions to reduce these behaviours. With correlates differing for screen and sedentary time, and between boys and girls, interventions may also benefit from including behaviour- and sex-specific strategies.
Journal Article
Outdoor time, screen time and sleep reported across early childhood: concurrent trajectories and maternal predictors
by
Zheng, Miaobing
,
Hesketh, Kylie D.
,
del Pozo Cruz, Borja
in
24-h movement behaviours
,
Behavior
,
Behavioral Sciences
2022
Background
Understanding the developmental trajectories of outdoor time, screen time and sleep is necessary to inform early interventions that promote healthy behaviours. This study aimed to describe concurrent trajectories of outdoor time, screen time and sleep across the early childhood period and their maternal predictors.
Methods
Data across five time points at child age 4, 9, 19, 42 and 60 months from the INFANT intervention were analysed. Mothers reported their child’s usual outdoor time, screen time and sleep duration, in addition to a range of maternal beliefs, attitudes, expectations and behaviours. Group-based multi-trajectory modelling was used to model concurrent trajectories of children’s behaviours. Multinomial logistic regression models determined the associations of maternal predictors with trajectory groups, adjusting for child sex and baseline age, intervention allocation, and clustering by recruitment.
Results
Of the 542 children recruited, 528 had data for outdoor time, screen time and sleep at one or more time points and were included in trajectory analyses Four trajectories were identified:
‘unstable sleep, increasing outdoor time, low screen’
(~ 22% of sample),
‘high outdoor time, low screen, high sleep’
(~ 24%),
‘high sleep, increasing outdoor time, low screen’
(~ 45%),
‘high screen, increasing outdoor time, high sleep’
(~ 10%). The
‘high sleep, increasing outdoor time, low screen’
group, comprising the largest percentage of the sample, demonstrated the healthiest behaviours. Predictors of group membership included: views of physically active children, screen time knowledge, screen time use, self-efficacy, physical activity optimism, future expectations for children’s physical activity and screen time, perceptions of floor play safety, and maternal physical activity, screen time, and sleep quality.
Conclusions
Four distinct trajectories of outdoor time, screen time and sleep were identified, with the most common (and healthiest) characterized by high levels of sleep. Maternal beliefs, attitudes, expectations and behaviours are important in the development of movement behaviour trajectories across early childhood. Future interventions and public policy may benefit from targeting these factors to support healthy movement behaviours from a young age.
Journal Article
Discovery of active off-axis hydrothermal vents at 9° 54′N East Pacific Rise
by
Dowd, William S.
,
Fornari, Daniel J.
,
Pittoors, Nicole C.
in
Active control
,
Dynamic stability
,
Earth, Atmospheric, and Planetary Sciences
2022
Comprehensive knowledge of the distribution of active hydrothermal vent fields along midocean ridges is essential to understanding global chemical and heat fluxes and endemic faunal distributions. However, current knowledge is biased by a historical preference for on-axis surveys. A scarcity of high-resolution bathymetric surveys in off-axis regions limits vent identification, which implies that the number of vents may be underestimated. Here, we present the discovery of an active, high-temperature, off-axis hydrothermal field on a fast-spreading ridge. The vent field is located 750 m east of the East Pacific Rise axis and ∼7 km north of on-axis vents at 9° 50′N, which are situated in a 50- to 100-m-wide trough. This site is currently the largest vent field known on the East Pacific Rise between 9 and 10° N. Its proximity to a normal fault suggests that hydrothermal fluid pathways are tectonically controlled. Geochemical evidence reveals deep fluid circulation to depths only 160 m above the axial magma lens. Relative to on-axis vents at 9° 50′N, these off-axis fluids attain higher temperatures and pressures. This tectonically controlled vent field may therefore exhibit greater stability in fluid composition, in contrast to more dynamic, dike-controlled, on-axis vents. The location of this site indicates that high-temperature convective circulation cells extend to greater distances off axis than previously realized. Thorough high-resolution mapping is necessary to understand the distribution, frequency, and physical controls on active off-axis vent fields so that their contribution to global heat and chemical fluxes and role in metacommunity dynamics can be determined.
Journal Article
Proportion of infants meeting the Australian 24-hour Movement Guidelines for the Early Years: data from the Melbourne InFANT Program
2017
Background
Little information is available on the movement behaviours of infants, despite evidence that these are important for development. The release of new Australian 24-hour Movement Guidelines provides an opportunity to document the current state of movement behaviours in infants relative to these guidelines. The aim of this study was to report the prevalence of 4 month old Australian infants meeting the 24-hour Movement Guidelines, individually, and in combination, and to describe associations with individual characteristics.
Methods
Maternal report baseline data from the Melbourne Infant Feeding, Activity and Nutrition Trial Program were used to determine prevalence of infants meeting physical activity (30 min of tummy time per day), sedentary behaviour (no more than 1 h at a time kept restrained; zero screen time), and sleep guidelines (14–17 h for 0–3 month olds or 12–16 h for 4–11 month olds). Prevalence of infants meeting combined guidelines was also described. The odds of meeting guidelines based on infant and family characteristics was determined.
Results
Data are reported for 455 infants with a mean age of 3.6 months (SD = 1.0). The proportion of infants meeting each of the guidelines was 29.7% for tummy time, 56.9% for kept restrained, 27.9% for screen time, 58.7% for sleep and 3.5% for the combined guidelines (i.e. meeting all four guidelines). A significantly higher proportion of girls than boys met the screen time guideline (32.5% versus 24.0%,
p
= 0.04) and the combined guidelines (5.7% versus 1.6%,
p
= 0.01). Few associations were observed between infant and family characteristics and proportion of infants meeting individual guidelines.
Conclusions
Very few infants met all of the guidelines contained in the new Australian 24-hour Movement Guidelines suggesting there is much room for improvement in movement behaviours from early life. Fewer infants met the tummy time and screen time guidelines hence these appear to be the behaviours requiring most attention. Parents and others providing care to infants require support and strategies to assist them in adhering to the guidelines to ensure optimal health and development for the youngest in our population.
Journal Article
Interventions to reduce sedentary behaviour in 0–5-year-olds: a systematic review and meta-analysis of randomised controlled trials
by
Hnatiuk, Jill A
,
Hesketh, Kylie D
,
Hinkley, Trina
in
Behavior
,
Child Behavior
,
Child, Preschool
2018
Aim or objectiveTo evaluate the effectiveness of behavioural interventions that report sedentary behaviour outcomes during early childhood.DesignSystematic review and meta-analysis.Data sourcesAcademic Search Complete, CINAHL Complete, Global Health, MEDLINE Complete, PsycINFO, SPORTDiscus with Full Text and EMBASE electronic databases were searched in March 2016.Eligibility criteria for selecting studiesInclusion criteria were: (1) published in a peer-reviewed English language journal; (2) sedentary behaviour outcomes reported; (3) randomised controlled trial (RCT) study design; and (4) participants were children with a mean age of ≤5.9 years and not yet attending primary/elementary school at postintervention.Results31 studies were included in the systematic review and 17 studies in the meta-analysis. The overall mean difference in screen time outcomes between groups was −17.12 (95% CI −28.82 to −5.42) min/day with a significant overall intervention effect (Z=2.87, p=0.004). The overall mean difference in sedentary time between groups was −18.91 (95% CI −33.31 to −4.51) min/day with a significant overall intervention effect (Z=2.57, p=0.01). Subgroup analyses suggest that for screen time, interventions of ≥6 months duration and those conducted in a community-based setting are most effective. For sedentary time, interventions targeting physical activity (and reporting changes in sedentary time) are more effective than those directly targeting sedentary time.Summary/conclusionsDespite heterogeneity in study methods and results, overall interventions to reduce sedentary behaviour in early childhood show significant reductions, suggesting that this may be an opportune time to intervene.Trial registration numberCRD42015017090.
Journal Article
Individuals aged 1-64 years with documented congenital heart defects at healthcare encounters, five U.S. surveillance sites, 2011-2013
2021
Many individuals born with congenital heart defects (CHD) survive to adulthood. However, population estimates of CHD beyond early childhood are limited in the U.S.
To estimate the percentage of individuals aged 1-to-64 years at five U.S. sites with CHD documented at a healthcare encounter during a three-year period and describe their characteristics.
Sites conducted population-based surveillance of CHD among 1 to 10-year-olds (three sites) and 11 to 64-year-olds (all five sites) by linking healthcare data. Eligible cases resided in the population catchment areas and had one or more healthcare encounters during the surveillance period (January 1, 2011-December 31, 2013) with a CHD-related ICD-9-CM code. Site-specific population census estimates from the same age groups and time period were used to assess percentage of individuals in the catchment area with a CHD-related ICD-9-CM code documented at a healthcare encounter (hereafter referred to as CHD cases). Severe and non-severe CHD were based on an established mutually exclusive anatomic hierarchy.
Among 42,646 CHD cases, 23.7% had severe CHD and 51.5% were male. Percentage of CHD cases among 1 to 10-year-olds, was 6.36/1,000 (range: 4.33-9.96/1,000) but varied by CHD severity [severe: 1.56/1,000 (range: 1.04-2.64/1,000); non-severe: 4.80/1,000 (range: 3.28-7.32/1,000)]. Percentage of cases across all sites in 11 to 64-year-olds was 1.47/1,000 (range: 1.02-2.18/1,000) and varied by CHD severity [severe: 0.34/1,000 (range: 0.26-0.49/1,000); non-severe: 1.13/1,000 (range: 0.76-1.69/1,000)]. Percentage of CHD cases decreased with age until 20 to 44 years and, for non-severe CHD only, increased slightly for ages 45 to 64 years.
CHD cases varied by site, CHD severity, and age. These findings will inform planning for the needs of this growing population.
Journal Article
Discovery of active off-axis hydrothermal vents at 9° 54'N East Pacific Rise
by
Downing, Connor C
,
Dowd, William S
,
Parnell-Turner, Ross
in
Biodiversity
,
Ecosystem
,
Hydrothermal Vents
2022
Comprehensive knowledge of the distribution of active hydrothermal vent fields along midocean ridges is essential to understanding global chemical and heat fluxes and endemic faunal distributions. However, current knowledge is biased by a historical preference for on-axis surveys. A scarcity of high-resolution bathymetric surveys in off-axis regions limits vent identification, which implies that the number of vents may be underestimated. Here, we present the discovery of an active, high-temperature, off-axis hydrothermal field on a fast-spreading ridge. The vent field is located 750 m east of the East Pacific Rise axis and ∼7 km north of on-axis vents at 9° 50'N, which are situated in a 50- to 100-m-wide trough. This site is currently the largest vent field known on the East Pacific Rise between 9 and 10° N. Its proximity to a normal fault suggests that hydrothermal fluid pathways are tectonically controlled. Geochemical evidence reveals deep fluid circulation to depths only 160 m above the axial magma lens. Relative to on-axis vents at 9° 50'N, these off-axis fluids attain higher temperatures and pressures. This tectonically controlled vent field may therefore exhibit greater stability in fluid composition, in contrast to more dynamic, dike-controlled, on-axis vents. The location of this site indicates that high-temperature convective circulation cells extend to greater distances off axis than previously realized. Thorough high-resolution mapping is necessary to understand the distribution, frequency, and physical controls on active off-axis vent fields so that their contribution to global heat and chemical fluxes and role in metacommunity dynamics can be determined.
Journal Article