Relationships Between Anthropometric Variables and the Internal Carotid Blood Flow

Assessment of peak systolic velocity (PSV) of the internal carotid artery (ICA) is utilized to examine stroke-symptomatic individuals for ICA stenosis. While a sedentary lifestyle is a common risk factor for ICA stenosis, a deeper understanding of how body composition affects ICA blood flow could provide insights before symptoms appear. PURPOSE: To examine the relationship between ICA blood flow and body composition variables. METHODS: ICA blood flow was assessed in eight healthy males (21.88 ± 2.25 years) on three different days to control for possible diurnal variability that could affect blood flow. Participants abstained from caffeine and physical activity for a minimum of 12 hours prior to each visit. Dual-energy X-ray absorptiometry was used to assess body fat percentage (BF%) and visceral fat area (VFA). Bioelectrical impedance (BIA) was used to assess body water percentage (BW%), metabolic age (MetA), and visceral fat rating (VFR). Participants rested supine with eyes closed for 5 minutes prior to assessment of ICA. B-mode doppler ultrasound sonography (7.5 MHz linear transducer) was used to measure PSV, end-diastolic velocity (EDV), resistance index (RI), and vessel diameter on the right ICA after 2 minutes of continual scanning with a 60° insonation angle. The relationship between ICA blood flow and body composition variables was examined via Pearson correlation analysis. RESULTS: BF% was positively correlated with ICA EDV (r = 0.669, p \u3c 0.001) and ICA PSV (r = 0.416, p = 0.043) but negatively correlated with ICA diameter (r = -0.424, p = 0.039). VFA was positively correlated with ICA EDV (r = 0.505, p = 0.012). BW% was negatively correlated with ICA PSV (r = -0.417, p = 0.043) and EDV (r = -0.620, p \u3c 0.001). MetA was positively correlated with ICA EDV (r = 0.630, p \u3c 0.001) but negatively correlated with ICA RI (r = -0.509, p = 0.011) and diameter (r = -0.513, p = 0.010). Similarly, VFR was positively correlated with ICA EDV (r = 0.644, p \u3c 0.001) but negatively correlated with ICA RI (r = -0.511, p = 0.011) and diameter (r = -0.496, p = 0.014). CONCLUSION: EDV has a greater correlation with body composition than PSV, suggesting that adiposity-related factors can describe ICA blood flow. Similarly, BIA might offer a solid and easy-to-attain procedure to indirectly assess ICA blood flow that warrants further research

The Impact of Nasal Breathing During Exercise on Cerebral Blood Flow

Achieving hypercapnic-induced vasodilation while exercising can increase cerebral blood flow (CBF) to a greater extent than during normoxic conditions. Evidence suggests that nasal breathing during a maximal aerobic effort can elicit a hypercapnic condition. PURPOSE: To compare the effect of combined (CB), oral (OB), and nasal (NB) breathing on CBF during a graded maximal exercise test (GXT). METHODS: Six healthy males (age: 21.83 ± 1.00 years) abstained from physical activity and caffeine for 12+ hours prior to a GXT. Three GXTs were performed (48+ hours between each trial) using a different randomized breathing condition (CB, OB, and NB). After a warm-up, participants completed a GXT until volitional fatigue on a semi-recumbent bicycle. Stages lasted 2 minutes and increased by a pre-set wattage at 70 rpm. Respiratory gases were assessed via a metabolic cart. Throughout the GXT, ultrasound sonography (7.5 MHz linear transducer) was utilized to assess the peak systolic velocity (PSV) and vessel diameter of the internal (ICA) and external (ECA) carotid artery on the right side of the neck. A one-way ANCOVA with mean arterial blood pressure and oxygen uptake (VO2) as covariates was utilized to compare the three breathing patterns at 40%, 55%, 70%, 85%, and 100% of VO2max. Data are presented as mean ± SEM. RESULTS: The partial pressure of exhaled CO2 (PECO2) was significantly greater (p = 0.008) during NB (33.16 ± 1.37 mmHg) compared to CB (26.63 ± 1.32 mmHg) and OB (26.72 ± 1.37) at 100% VO2max. While not statistically significant, there was a greater PSV in the ICA during NB (99.72 ± 7.12 cm/s) compared to CB (87.34 ± 9.36 cm/s) and OB (89.63 ± 9.77 cm/s) at 100% VO2max. Similarly, there was a greater PSV in the ICA during NB (102.53 ± 8.07 cm/s) compared to CB (93.13 ± 7.79 cm/s) and OB (81.25 ± 7.80 cm/s) at 85% VO2max. In contrast, there was a significantly greater (p = 0.027) PSV in the ICA during NB (126.12 ± 7.51 cm/s) compared to OB (92.47 ± 7.34 cm/s) but not CB (111.91 ± 7.14 cm/s) at 70% VO2max. There were no significant differences in the PSV of the ECA nor the diameter of the ICA and ECA. CONCLUSION: NB during a GXT increased PSV in the ICA compared to CB and OB, which might be partly related to an increased systemic concentration of CO2. A greater increase in PSV in the ICA represents a greater CBF that might provide greater cognitive health benefits than while exercising with either CB or OB. Studies with a bigger sample size will provide greater statistical power to examine the benefits of increasing the PSV in the ICA and its effect on cognitive health

Evaluation of Body Fat Percentage with Vertical and Longitudinal Skinfolds

Subcutaneous fat content, as well as body fat percentage (BF%), can be effectively assessed using skinfold calipers. While skinfolds (SFs) are practical and easy to attain, their accuracy could be reduced if the SFs are not collected with the ideal fold orientation. PURPOSE: To determine if vertical or longitudinal SFs in the trunk area are better predictors of BF%. METHODS: A pool of thirty-eight male (21.29 ± 4.59 yrs, 15.68 ± 4.82 BF%) and twenty-two female (21.14 ± 4.05 yrs, 26.63 ± 5.34 BF%) participants completed the study. A dual-energy X-ray absorptiometry scan was utilized to assess BF%. Using a Lange caliper, one technician assessed all SFs within the trunk in triplicate using both a vertical pinch and a longitudinal pinch. SFs sites included: 2 cm left, right, superior, and inferior of the umbilicus; left and right anterior mid-axillary line at the level of the navel; 2 cm left and right of the vertebral column at the level of the navel; midsternal line at the slimmest part of the waist and at the level of the xiphoid process. In addition, two commonly assessed diagonal folds (right suprailiac and subscapular) were collected. The relationship between SFs orientation and BF% was assessed utilizing a Pearson correlation. Stepwise linear regression was utilized to predict BF%. Data are presented as mean ± SD. RESULTS: Overall, vertical folds for both males and females had a higher correlation with BF% than longitudinal folds. The right vertical mid-axillary (RVMA) SFs had a significant correlation with BF% for both male (r = 0.864, p \u3c 0.001) and female (r = 0.712, p \u3c 0.001) participants. Similarly, the subscapular (SS) SFs had a significant correlation with BF% for both male (r = 0.851, p \u3c 0.001) and female (r = 0.788, p \u3c 0.001) participants. BF% was successfully predicted [4.142 + (10.154 * Sex) + (0.255 * RVMA) + (0.516 * SS), adjusted R2 = 0.874], where sex (0 = male, 1 = female). The average RVMA SFs were 18.43 ± 7.85 mm for males and 19.91 ± 6.78 mm for females, while the SS SFs were 13.50 ± 4.95 mm for males and 14.05 ± 5.34 mm for females. CONCLUSION: Although RVMA SFs are not commonly utilized to estimate BF%, there is evidence of a high correlation with BF%. The applicability of utilizing the RVMA jointly with the SS SFs as a fast yet reliable method to estimate BF% should be examined in a large and diverse cohort

The Effect on Carbon Dioxide Production During Maximal Exercise with Distinct Breathing Mechanisms

Nasal breathing (NB) may lead to lower maximal oxygen uptake (VO2max) compared to oral breathing (OB) or nasal/oral combined breathing (CB) due to a transient increase in the systemic concentration of carbon dioxide (CO2) that can replicate the effects of a hypoxic environment. The exercise intensity at which NB can elicit this response is poorly understood. PURPOSE: To examine the increase in the fractional rate of exhaled CO2 (FECO2) and FEO2 with different breathing conditions during a graded maximal aerobic exercise test (GXT). METHODS: Eight healthy males (21.88 ± 0.46 years) completed 3 GXTs (separated by 48+ hours of recovery) using a different randomly assigned breathing condition (NB, OB, and CB). Participants exercised on a semi-recumbent bicycle at a pedaling speed of 70 rpm, increasing resistance every 2 minutes until volitional fatigue. Following the GXT, participants had a 2-minute recovery. Expired respiratory gases were collected via a metabolic cart. Six time points (40%, 55%, 70%, 85%, 100% VO2max, and recovery) were compared between NB, OB, and CB. Data are presented as mean ± SD. RESULTS: FECO2 was significantly higher during NB than OB at 70% [4.52 ± 0.37 vs. 4.07 ± 0.26%, p = 0.031 and 85% (4.49 ± 0.43% vs. 3.80 ± 0.32%, p = 0.009) of VO2max. Additionally, FECO2 at 100% of VO2max was significantly higher (p = 0.001) during NB (4.33 ± 0.69%) than OB (3.47 ± 0.29%) and CB (3.55 ± 0.19%). The transient change in FECO2 during exercise rapidly changed after the 2-minute recovery, where NB = 3.75 ± 0.71%, OB = 3.38 ± 0.17%, and CB = 3.30 ± 0.27%. FEO2 was significantly lower during NB than OB at 70% (16.34 ± 0.45% vs. 17.04 ± 0.3%, p = 0.011) and 85% (16.50 ± 0.53% vs. 17.32 ± 0.38%, p = 0.009) of VO2max. FEO2 was significantly lower (p = 0.003) during NB (16.66 ± 0.91%) compared to OB (17.67 ± 0.33%) and CB (17.61 ± 0.26%) at 100% VO2max. The transient change in FEO2 during exercise rapidly changed after the 2-minute recovery, where NB = 17.67 ± 1.00%, OB = 18.03 ± 0.23%, and CB = 18.20 ± 0.17%. CONCLUSION: NB elicits an exercised-induced increase in FECO2 that is analogous to a decrease in FEO2 starting at 70% of VO2max. Given the transient increase in FECO2, NB should be considered as a potential breathing method and further explored to replicate a temporary hypoxic environment that could promote a greater exercise adaptation than CB or OB might do

Describing Visceral Fat via Girth and Skinfold Measurements

While girth ratios (GR), such as waist-to-height ratio (WHtR) and waist-to-hip ratio (WHR), and body fat percentage (BF%) have been widely used to describe visceral fat (VF), the applicability of skinfold (SF) measurements has been given less attention for the same purpose. PURPOSE: This study examined the associations between BF%, GR, SF, and VF. METHODS: Sixty healthy participants (38 males and 22 females, age = 21.23 ± 4.37 years, BMI = 24.87 ± 3.02 kg/m2, BF% = 19.70 ± 7.28%) participated in the study. Girth ratios, including WHtR and WHR, were assessed using a Gulick tape specifically at the level of the navel and slimmest part of the waist. SF thickness was assessed using a Lange skinfold caliper at 5 different regions, including the navel, upper abdomen, axillary, lumbar, and subscapular. Dual-energy X-ray absorptiometry was used to determine VF. A Pearson correlation was utilized to examine the associations among BF%, GR, SF, and VF. RESULTS: Females’ VF (33.9 ± 16.9 cm2) was significantly correlated with BMI (23.9 ± 3.7 kg/m2, r = .451, p = .035) and BF% (26.6 ± 5.3%, r = .590, p = .004), while males’ VF (49.6 ± 10.9 cm2) was not correlated with BMI (25.4 ± 2.4 kg/m2, r = -.021, p = .899) nor BF% (15.7 ± 4.8%, r = -.084, p = .616). In addition, WHR (.85 ± .04) was correlated with VF in males (r = .462, p = .004), while WHtR (.47 ± .06) was correlated with VF (r = .616, p = .002) in females. When participants were clustered into two groups based on BMI (\u3c 25 or ≥ 25 kg/m2), VF was correlated with the WHR in males (n = 18) with a BMI ≥ 25 kg/m2 (r = .522, p = .026) and in women (n = 14) with a BMI \u3c 25 kg/m2 (r = .567, p = .035). However, males (n = 20) with a BMI \u3c 25 kg/m2 and women (n = 8) with a BMI ≥ 25 kg/m2 had no correlations between VF and any GR or SF measurements. Although there was no correlation between VF and SF in males, VF in females was correlated with SF at the anterior slimmest part of the waist (16.1 ± 4.9 mm, r = .450, p = .035), iliac crest (14.0 ± 5.4 mm, r = .527, p = .012), and subscapular (14.0 ± 5.3 mm, r = .51, p = .018). CONCLUSION: BF% has a greater correlation with VF in females than in males, while WHR (a marker of body fat distribution) better explains VF in males. In addition, SF only held a degree of applicability within females. Furthermore, fat content seems to play a more important role in females when assessing VF content, while fat distribution seems to be more important in males

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same regio

A framework of transient hypercapnia to achieve an increased cerebral blood flow induced by nasal breathing during aerobic exercise

During exercise, cerebral blood flow (CBF) is expected to only increase to a maximal volume up to a moderate intensity aerobic effort, suggesting that CBF is expected to decline past 70 % of a maximal aerobic effort. Increasing CBF during exercise permits an increased cerebral metabolic activity that stimulates neuroplasticity and other key processes of cerebral adaptations that ultimately improve cognitive health. Recent work has focused on utilizing gas-induced exposure to intermittent hypoxia during aerobic exercise to maximize the improvements in cognitive function compared to those seen under normoxic conditions. However, it is postulated that exercising by isolating breathing only to the nasal route may provide a similar effect by stimulating a transient hypercapnic condition that is non-gas dependent. Because nasal breathing prevents hyperventilation during exercise, it promotes an increase in the partial arterial pressure of CO2. The rise in systemic CO2 stimulates hypercapnia and permits the upregulation of hypoxia-related genes. In addition, the rise in systemic CO2 stimulates cerebral vasodilation, promoting a greater increase in CBF than seen during normoxic conditions. While more research is warranted, nasal breathing might also promote benefits related to improved sleep, greater immunity, and body fat loss. Altogether, this narrative review presents a theoretical framework by which exercise-induced hypercapnia by utilizing nasal breathing during moderate-intensity aerobic exercise may promote greater health adaptations and cognitive improvements than utilizing oronasal breathing

Global, regional, and national burden of traumatic brain injury and spinal cord injury, 1990-2016 : a systematic analysis for the Global Burden of Disease Study 2016

Background Traumatic brain injury (TBI) and spinal cord injury (SCI) are increasingly recognised as global health priorities in view of the preventability of most injuries and the complex and expensive medical care they necessitate. We aimed to measure the incidence, prevalence, and years of life lived with disability (YLDs) for TBI and SCI from all causes of injury in every country, to describe how these measures have changed between 1990 and 2016, and to estimate the proportion of TBI and SCI cases caused by different types of injury. Methods We used results from the Global Burden of Diseases, Injuries, and Risk Factors (GBD) Study 2016 to measure the global, regional, and national burden of TBI and SCI by age and sex. We measured the incidence and prevalence of all causes of injury requiring medical care in inpatient and outpatient records, literature studies, and survey data. By use of clinical record data, we estimated the proportion of each cause of injury that required medical care that would result in TBI or SCI being considered as the nature of injury. We used literature studies to establish standardised mortality ratios and applied differential equations to convert incidence to prevalence of long-term disability. Finally, we applied GBD disability weights to calculate YLDs. We used a Bayesian meta-regression tool for epidemiological modelling, used cause-specific mortality rates for non-fatal estimation, and adjusted our results for disability experienced with comorbid conditions. We also analysed results on the basis of the Socio-demographic Index, a compound measure of income per capita, education, and fertility. Findings In 2016, there were 27.08 million (95% uncertainty interval [UI] 24.30-30.30 million) new cases of TBI and 0.93 million (0.78-1.16 million) new cases of SCI, with age-standardised incidence rates of 369 (331-412) per 100 000 population for TBI and 13 (11-16) per 100 000 for SCI. In 2016, the number of prevalent cases of TBI was 55.50 million (53.40-57.62 million) and of SCI was 27.04 million (24 .98-30 .15 million). From 1990 to 2016, the age-standardised prevalence of TBI increased by 8.4% (95% UI 7.7 to 9.2), whereas that of SCI did not change significantly (-0.2% [-2.1 to 2.7]). Age-standardised incidence rates increased by 3.6% (1.8 to 5.5) for TBI, but did not change significantly for SCI (-3.6% [-7.4 to 4.0]). TBI caused 8.1 million (95% UI 6. 0-10. 4 million) YLDs and SCI caused 9.5 million (6.7-12.4 million) YLDs in 2016, corresponding to age-standardised rates of 111 (82-141) per 100 000 for TBI and 130 (90-170) per 100 000 for SCI. Falls and road injuries were the leading causes of new cases of TBI and SCI in most regions. Interpretation TBI and SCI constitute a considerable portion of the global injury burden and are caused primarily by falls and road injuries. The increase in incidence of TBI over time might continue in view of increases in population density, population ageing, and increasing use of motor vehicles, motorcycles, and bicycles. The number of individuals living with SCI is expected to increase in view of population growth, which is concerning because of the specialised care that people with SCI can require. Our study was limited by data sparsity in some regions, and it will be important to invest greater resources in collection of data for TBI and SCI to improve the accuracy of future assessments. Copyright (C) 2018 The Author(s). Published by Elsevier Ltd.Peer reviewe

Multiple loci on 8q24 associated with prostate cancer susceptibility

Previous studies have identified multiple loci on 8q24 associated with prostate cancer risk. We performed a comprehensive analysis of SNP associations across 8q24 by genotyping tag SNPs in 5,504 prostate cancer cases and 5,834 controls. We confirmed associations at three previously reported loci and identified additional loci in two other linkage disequilibrium blocks (rs1006908: per-allele OR = 0.87, P = 7.9 x 10(-8); rs620861: OR = 0.90, P = 4.8 x 10(-8)). Eight SNPs in five linkage disequilibrium blocks were independently associated with prostate cancer susceptibility