Some problems in planning a high school commercial curriculum

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An investigation into skeletal muscle insulin signalling and systemic inflammation as potential mechanisms responsible for the impairment in glucose regulation following acute sleep restriction in healthy males

Sleep restriction is associated with impaired glucose regulation, which is a risk factor for developing type 2 diabetes. However, the underlying mechanisms leading to this impairment are unknown. This thesis aims to examine the effects of partial sleep restriction on whole body metabolism, and investigate whether the impairment in insulin sensitivity observed after sleep restriction is coupled with changes in systemic inflammation and skeletal muscle insulin signalling. A pilot study was carried out to assess whether or not two nights of partial sleep restriction would alter glucose regulation and substrate utilisation. 10 healthy males then participated in a separate randomised crossover study involving two nights of habitual sleep (control) and two nights of 50% of habitual sleep (sleep restriction). An oral glucose tolerance test was carried out after the second night of each condition to assess whole body glucose tolerance, insulin sensitivity and inflammation, and to examine skeletal muscle insulin signalling. The pilot study findings confirmed that two nights of partial sleep restriction impaired glucose tolerance. Findings from the main study revealed no effect of trial on glucose tolerance (P = .222). Insulin sensitivity estimated by the Matsuda Index was 18.6% lower in the sleep restriction condition (P = .010). CRP and TNFα were similar between trials (P > 0.05). Fold change in PKB activity from baseline tended to be lower following sleep restriction at 30 min (P = .098) and 120 min (P = .087). AUC for insulin to PKB index was significantly higher in the sleep restriction condition (P = .012). Phosphorylated to total PKB was similar between conditions (P = .217). Two nights of sleep restriction decreased insulin sensitivity in healthy males. This impairment was not coupled by increased systemic inflammation. Skeletal muscle insulin signalling showed conflicting findings, suggesting a possible disruption of skeletal muscle insulin signalling

The effect of short sleep duration and exercise on glycaemic control in healthy adults

Short sleep durations are common amongst adults across the world. They have been linked to metabolic disorders, and, more specifically, impaired glycaemic control. Acute and chronic physical activity are known to have beneficial effects on metabolic health, and therefore may be able to attenuate the link between short sleep and impaired glycaemic control. The purpose of this thesis was to explore the potential for exercise to alter glycaemic control in short sleep durations. Specifically, the aims were threefold: (a) to understand the impaired glycaemic response to glucose intake over consecutive nights of sleep restriction (Chapter 4); (b) to investigate if exercise could alleviate the sleep restriction induced impairment in insulin sensitivity (Chapter 5); and (c) to determine if these factors act in a similar manner when transferred to the free-living environment (Chapter 6). The findings in Chapter 4 demonstrated that the number of nights of sleep restriction did not appear to affect the impairment in glycaemic control. These findings informed the study in Chapter 5, which used a randomised cross-over design to explore the potential for acute exercise to attenuate the impairment in glucose regulation after a single night of sleep restriction. The findings suggest that sprint interval exercise may be beneficial for the late postprandial period after sleep restriction, as demonstrated by a reduced insulin area under the curve. However, when examined in the free-living environment (Chapter 6), habitual short sleep duration did not show any evidence of impairing markers of glycaemic control when confounding factors such as sex, diet, and body composition were taken into consideration. Collectively, the studies in this thesis confirm that short-term short sleep impairs glucose regulation and suggest that exercise may be beneficial for glucose regulation after short sleep in the acute setting, but findings may be contradictory in chronic settings. Further study is warranted to establish the effects of different exercise modalities on glucose regulation after sleep restriction and to fully understand the link between habitual sleep duration, physical activity, and glycaemic control. However, a session of sprint interval exercise could be recommended to individuals after acute sleep restriction to alleviate the impairment in insulin sensitivity

An examination of self-defining memories, cognitive avoidance and metacognitive processes in depressed and non-depressed older adults

Background: Self-defining memories (SDMs) are key memories that describe how a person has come to be the person they currently are. Key events in one’s life, and the way that they are recalled can have a dramatic impact on sense of self, and this can contribute to depression. Therefore understanding SDMs and the processes that affect their recall is of important clinical value. This research extends Singer et al.’s (2007) research by examining OAs with depression. Research questions: This study examined the characteristics of depressed and non-depressed OAs SDMs along the dimensions of content, affective valence, memory specificity and the ability to derive meaning from memories. Additionally, the study explored contributors to overgeneral memory by measuring cognitive avoidance and assessing metacognitive factors in meaning making ability. Methods: A cross-sectional between groups study of 16 depressed and 19 non-depressed OAs. Participants completed the Montreal Cognitive Assessment, the Geriatric Depression Scale, the Metacognitions Questionnaire-30, the White Bear Suppression Inventory, the Self-defining Memory Task and the Self-defining Memory Rating Sheet. The groups were reasonably well matched on demographic variables except for education, gender and physical health problems. Results: Depressed OAs recalled fewer specific memories than non-depressed OAs and were less able to derive meaning from their memories. However, when years of education was controlled for in a partial correlation, the correlations between depression scores, memory specificity and meaning making ability were no longer significant. Cognitive avoidance was not significantly correlated with memory specificity and metacognition was not significantly correlated with meaning making ability. Conclusions: These results are broadly consistent with previous studies of overgeneral memory in individuals with depression. The results raise the possibility that years of education also contributed to the differences between the two groups and so potential interpretations of this finding are also presented. None of the psychological mechanisms investigated were significantly correlated with memory specificity or integrative meaning. Larger samples and demographically matched groups are required to conduct mediation analyses on factors influencing over general memory and meaning making ability in SDMs. Keywords: Depression; self-defining memories; memory specificity; avoidance; and metacognition

Fruit and vegetable intake and body adiposity among populations in Eastern Canada: The Atlantic Partnership for Tomorrow's Health Study

Objectives The prevalence of obesity among populations in the Atlantic provinces is the highest in Canada. Some studies suggest that adequate fruit and vegetable consumption may help body weight management. We assessed the associations between fruit and vegetable intake with body adiposity among individuals who participated in the baseline survey of the Atlantic Partnership for Tomorrow’s Health (Atlantic PATH) cohort study.Methods We carried out a cross-sectional analysis among 26 340 individuals (7979 men and 18 361 women) aged 35–69 years who were recruited in the baseline survey of the Atlantic PATH study. Data on fruit and vegetable intake, sociodemographic and behavioural factors, chronic disease, anthropometric measurements and body composition were included in the analysis.Results In the multivariable regression analyses, 1 SD increment of total fruit and vegetable intake was inversely associated with body mass index (−0.12 kg/m2; 95% CI −0.19 to –0.05), waist circumference (−0.40 cm; 95% CI −0.58 to –0.23), percentage fat mass (−0.30%; 95% CI −0.44 to –0.17) and fat mass index (−0.14 kg/m2; 95% CI −0.19 to –0.08). Fruit intake, but not vegetable intake, was consistently inversely associated with anthropometric indices, fat mass, obesity and abdominal obesity.Conclusions Fruit and vegetable consumption was inversely associated with body adiposity among the participant population in Atlantic Canada. This association was primarily attributable to fruit intake. Longitudinal studies and randomised trials are warranted to confirm these observations and investigate the underlying mechanisms

Adiposity Measures and Plasma Adipokines in Females with Rheumatoid and Osteoarthritis

The objective of this study was to examine the relationship between adipokines and adiposity in individuals with rheumatoid and osteoarthritis in the Atlantic PATH cohort. Using a nested case-control analysis, participants in the Atlantic PATH cohort with rheumatoid or osteoarthritis were matched for measures of adiposity with participants without a history of arthritis. Both measured and self-reported data were used to examine disease status, adiposity, and lifestyle factors. Immunoassays were used to measure plasma markers. BMI was positively correlated with percentage body fat, fat mass index (FMI), and a change in BMI from 18 years of age in all 3 groups. There were no statistical differences between levels of plasma adipokines; adiponectin levels were 6.6, 7.9, and 8.2 μg/ml, leptin levels were 10.3, 13.7, and 11.5 ng/ml, and resistin levels were 10.0, 12.1, and 10.8 ng/ml in participants without arthritis, with rheumatoid arthritis, and with osteoarthritis, respectively. Those with higher levels of adiponectin were more likely to have osteoarthritis (but not rheumatoid arthritis). No association was found between arthritis types and leptin or resistin. This study demonstrates differences in measures of adiposity and adipokines in specific types of arthritis and highlights the need for more research targeting specific adipokines during arthritic disease progression

Adverse pregnancy and birth outcomes associated with Mycoplasma hominis, Ureaplasma urealyticum and Ureaplasma parvum: a systematic review and meta-analysis.

OBJECTIVES Mycoplasma hominis, Ureaplasma urealyticum and Ureaplasma parvum (genital mycoplasmas) commonly colonise the urogenital tract in pregnant women. This systematic review aims to investigate their role in adverse pregnancy and birth outcomes, alone or in combination with bacterial vaginosis (BV). METHODS We searched Embase, Medline and CINAHL databases from January 1971 to February 2021. Eligible studies tested for any of the three genital mycoplasmas during pregnancy and reported on the primary outcome, preterm birth (PTB) and/or secondary outcomes low birth weight (LBW), premature rupture of membranes (PROM), spontaneous abortion (SA) and/or perinatal or neonatal death (PND).Two reviewers independently screened titles and abstracts, read potentially eligible full texts and extracted data. Two reviewers independently assessed risks of bias using published checklists. Random effects meta-analysis was used to estimate summary ORs (with 95% CIs and prediction intervals). Multivariable and stratified analyses were synthesised descriptively. RESULTS Of 57/1194 included studies, 39 were from high-income countries. In meta-analysis of unadjusted ORs, M. hominis was associated with PTB (OR 1.87, 95% CI 1.49 to 2.34), PROM, LBW and PND but not SA. U. urealyticum was associated with PTB (OR 1.84, 95% CI 1.34 to 2.55), PROM, LBW, SA and PND. U. parvum was associated with PTB (1.60, 95% CI 1.12 to 2.30), PROM and SA. Nine of 57 studies reported any multivariable analysis. In two studies, analyses stratified by BV status showed that M. hominis and U. parvum were more strongly associated with PTB in the presence than in the absence of BV. The most frequent source of bias was a failure to control for confounding. CONCLUSIONS The currently available literature does not allow conclusions about the role of mycoplasmas in adverse pregnancy and birth outcomes, alone or with coexisting BV. Future studies that consider genital mycoplasmas in the context of the vaginal microbiome are needed. PROSPERO REGISTRATION NUMBER CRD42016050962

The relationship between anthropometric measures and cardiometabolic health in shift work: findings from the Atlantic PATH Cohort Study

PurposeTo evaluate the relationship between anthropometric measures and cardiometabolic health in shift workers compared to non-shift workers.MethodsA population health study was conducted with 4155 shift workers and 8258 non-shift workers from the Atlantic Partnership for Tomorrow’s Health (PATH) cohort. Linear and logistic regression models were used to assess the differences in anthropometric measures (body adiposity) and self-reported cardiometabolic disease outcomes (obesity, diabetes, and cardiovascular disease) between shift workers and non-shift workers.ResultsThere was a significant increased risk of cardiovascular disease, obesity, and diabetes among shift workers compared to matched controls despite higher levels of physical activity and lower levels of sedentary behaviour. Shift workers were 17% more likely to be obese (95% CI 7–27) and 27% more likely to have diabetes (95% CI 8–51). The strength of this association was demonstrated by also controlling for body mass index and fat mass index.ConclusionsShift work is associated with obesity, cardiovascular disease, and diabetes despite higher levels of physical activity and lower levels of sedentary behaviour. The association between shift work and cardiometabolic health was independent of body mass index for cardiovascular disease and diabetes, and independent of fat mass index for diabetes