58 research outputs found

    Screen Time and Body Image in Icelandic Adolescents : Sex-Specific Cross-Sectional and Longitudinal Associations

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    Funding Information: Funding: This research was funded by The University of Iceland Research Fund, grant number. HI16120043, and the Icelandic Centre for research (RANNIS), grant number 152509-051. Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Studies of adolescent body image and screen use are mostly limited to girls, and longitudinal data are scarce. We examined cross-sectional and longitudinal associations between these variables in mid-adolescent boys and girls. Data was collected when participants were at age 15 and 17, by questionnaire and objective measurements (n = 152 had complete data). Sex-specific linear regression was used to explore cross-sectional and longitudinal associations of self-reported screen use (total use, and time spent in gaming, TV/DVD/internet-based watching and internet use for communication) and body image, adjusting for vigorous physical activity, symptoms of depression, and body composition. Screen time was negatively associated with body image at both time points, although more strongly at age 15, and for girls only. Gaming and TV/DVD/internet watching was more strongly associated with body image than internet use for communication. Girls with above median screen time at both ages had 14% lower body image score at age 17 than girls with below median screen time at both time points. Our results suggest that screen use is likely to play a role in the development of body dissatisfaction among adolescent females. Limiting screen time may, therefore, help to mitigate body dissatisfaction in adolescent girls.Peer reviewe

    Extracellular nucleotides ATP and UTP induce a marked acute release of tissue-type plasminogen activator in vivo in man

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    Extracellular nucleotides such as ATP and UTP are released by activation of platelets and ischemic tissue injury. The aim of the present study was to investigate whether ATP and UTP can induce acute tPA release from the vascular endothelium in vivo. Nine healthy subjects were studied in a perfused-forearm model during stepwise intraarterial infusions of ATP and UTP (10-200 nmol/min), and UTP during inhibition of prostanoid and NO synthesis by indomethacin and L-NMMA. ATP and UTP induced a similar and marked stimulation of forearm tPA release which increased 11- and 18-fold above baseline (p < or =0.01 for both) in conjunction with pronounced vasodilation. Neither the acute tPA release nor the vasodilation could be abrogated by NO and prostanoid synthesis inhibition. The similar effect of ATP and UTP suggests that P2Y rather than adenosine receptors mediate the response. Release of extracellular nucleotides in ischemic tissue may induce a pronounced activation of the endogenous fibrinolytic system

    Forearm blood flow responses to neuropeptide Y, noradrenaline and adenosine 5'-triphosphate in hypertensive and normotensive subjects

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    Neuropeptide Y (NPY), noradrenaline (NA) and adenosine 5'-triphosphate (ATP) are important co-transmitters in the sympathetic nervous system, which has a central role in cardiovascular control. In order to evaluate if hypertension is associated with alterations in vascular responses to sympathetic co-transmitters we studied the effects of intra-arterial infusion of NPY, NA and ATP on forearm blood flow. Blood flow was measured by venous occlusion plethysmography in six hypertensive (mean arterial blood pressure (MAP) 113 +/- 4 mmHg) and six matched normotensive subjects (MAP 97 +/- 3 mmHg). NPY and NA significantly reduced forearm blood flow, while a powerful increase was seen with ATP. Forearm vascular resistance, calculated as MAP divided by forearm blood flow, was significantly increased by NPY and NA and strongly reduced by ATP. There was no difference between hypertensive and normotensive subjects in response to either transmitter. In conclusion, vascular reactivity to intra-arterial administration of NPY, NA and ATP seems to be intact in hypertensive patients without metabolic aberrations

    Consistency of blood pressure and impact on cardiovascular structure over 20 years in young men

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    To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldOBJECTIVE: To identify, in a prospective study, how blood pressure levels at the age of twenty predict hypertension and cardiovascular remodelling 20 years later. METHODS: Twenty-year-old men with blood pressure (BP) elevation [systolic blood pressure (SBP) 140-160 and/or diastolic blood pressure (DBP) 85-95 mmHg; blood pressure elevation (BPE) group] or normal BP [SBP 110-130 and DBP 60-80 mmHg; normal controls (NC) group] entered the study in 1987. In 2007, follow-up was conducted including ambulatory BP, echocardiography, anthropometric and intima media thickness (IMT) measurements. RESULTS: Assessed with 24-h ambulatory BP, the prevalence of hypertension was 35/47 (74.5%) and 1/17 (5.9%) in the BPE and NC group at follow-up respectively. Twenty-four hour mean arterial pressure (MAP) increased from 86.6 (0.8) to 97.2 (1.2) (P < 0.0001), and from 83.1 (1.5) to 88.1 (1.2) mmHg (P < 0.01) from baseline to follow-up in the BPE and NC group respectively. At follow-up, left ventricular mass index (LVMI) was 122 (4) and 106 (4) g m(-1) in the BPE and NC group (unpaired t-test; P < 0.01) respectively, whilst IMT was 0.61 (0.01) and 0.57 (0.01) mm in the BPE and NC group (P < 0.05) respectively. In a logistic regression model, prevalence of hypertension was best explained by office MAP and 24-h DBP at baseline (R(2) 0.333; P < 0.05). A combined model of office MAP, body mass index and insulin levels at baseline explained 56% of LVMI at follow-up. CONCLUSIONS: BP elevation in young age predicts hypertension and adverse cardiovascular remodelling at the age of 40 years. Baseline office MAP is the best predictor of hypertension, 24-h MAP and LVMI
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