Riviste scientifiche

Humans have shaped the Serengeti’s ecosystems since the Stone Age

New Scientist - Me, 29/08/2018 - 19:00
Remains of dung from 3700 years ago reveal how it was nomadic herders, not nature, that seeded the Serengeti’s unique ecosystems

CERN’s mini particle accelerator could finally smash apart electrons

New Scientist - Me, 29/08/2018 - 19:00
We’ve never accelerated electrons to high enough energies to smash them apart before, but a new machine at the home of the Large Hadron Collider is a step towards doing so

Prehistoric girl had parents belonging to different human species

New Scientist - Me, 29/08/2018 - 18:00
A sliver of bone once belonged to “Denny”, the child of a Neanderthal mother and a Denisovan father – the first such first-generation hybrid ever found

Why an orbiting moon station is the worst idea of the new space age

New Scientist - Me, 29/08/2018 - 16:26
US Vice President Mike Pence says a habitable base orbiting the moon will be built and in use by 2024. It's a pointless distraction, warns Mars Society president Robert Zubrin

Ebola outbreak has killed 75 in the Democratic Republic of Congo

New Scientist - Me, 29/08/2018 - 15:00
There has been an uptick in deaths caused by the Ebola virus in the Democratic Republic of Congo, bringing the death count for the current outbreak up to 75

Subtle patterns in your typing could reveal early signs of Parkinson’s

New Scientist - Me, 29/08/2018 - 14:33
How you type could reveal early signs of Parkinson’s disease, including subtle tremors, before serious changes in the brain have occurred

Breastfeeding in low-resource settings: Not a “small matter”

PLoS Medicine - Ma, 28/08/2018 - 22:00

by Lars Åke Persson

Despite its clear biological benefits, many infants globally do not receive exclusive breastfeeding. In a Guest Editorial, Lars Åke Persson discusses what is needed to make breastfeeding the social norm.

Crowdsourcing to expand HIV testing among men who have sex with men in China: A closed cohort stepped wedge cluster randomized controlled trial

PLoS Medicine - Ma, 28/08/2018 - 22:00

by Weiming Tang, Chongyi Wei, Bolin Cao, Dan Wu, Katherine T. Li, Haidong Lu, Wei Ma, Dianmin Kang, Haochu Li, Meizhen Liao, Katie R. Mollan, Michael G. Hudgens, Chuncheng Liu, Wenting Huang, Aifeng Liu, Ye Zhang, M. Kumi Smith, Kate M. Mitchell, Jason J. Ong, Hongyun Fu, Peter Vickerman, Ligang Yang, Cheng Wang, Heping Zheng, Bin Yang, Joseph D. Tucker

Background

HIV testing rates are suboptimal among at-risk men. Crowdsourcing may be a useful tool for designing innovative, community-based HIV testing strategies to increase HIV testing. The purpose of this study was to use a stepped wedge cluster randomized controlled trial (RCT) to evaluate the effect of a crowdsourced HIV intervention on HIV testing uptake among men who have sex with men (MSM) in eight Chinese cities.

Methods and findings

An HIV testing intervention was developed through a national image contest, a regional strategy designathon, and local message contests. The final intervention included a multimedia HIV testing campaign, an online HIV testing service, and local testing promotion campaigns tailored for MSM. This intervention was evaluated using a closed cohort stepped wedge cluster RCT in eight Chinese cities (Guangzhou, Shenzhen, Zhuhai, and Jiangmen in Guangdong province; Jinan, Qingdao, Yantai, and Jining in Shandong province) from August 2016 to August 2017. MSM were recruited through Blued, a social networking mobile application for MSM, from July 29 to August 21 of 2016. The primary outcome was self-reported HIV testing in the past 3 months. Secondary outcomes included HIV self-testing, facility-based HIV testing, condom use, and syphilis testing. Generalized linear mixed models (GLMMs) were used to analyze primary and secondary outcomes. We enrolled a total of 1,381 MSM. Most were ≤30 years old (82%), unmarried (86%), and had a college degree or higher (65%). The proportion of individuals receiving an HIV test during the intervention periods within a city was 8.9% (95% confidence interval [CI] 2.2–15.5) greater than during the control periods. In addition, the intention-to-treat analysis showed a higher probability of receiving an HIV test during the intervention periods as compared to the control periods (estimated risk ratio [RR] = 1.43, 95% CI 1.19–1.73). The intervention also increased HIV self-testing (RR = 1.89, 95% CI 1.50–2.38). There was no effect on facility-based HIV testing (RR = 1.00, 95% CI 0.79–1.26), condom use (RR = 1.00, 95% CI 0.86–1.17), or syphilis testing (RR = 0.92, 95% CI 0.70–1.21). A total of 48.6% (593/1,219) of participants reported that they received HIV self-testing. Among men who received two HIV tests, 32 individuals seroconverted during the 1-year study period. Study limitations include the use of self-reported HIV testing data among a subset of men and non-completion of the final survey by 23% of participants. Our study population was a young online group in urban China and the relevance of our findings to other populations will require further investigation.

Conclusions

In this setting, crowdsourcing was effective for developing and strengthening community-based HIV testing services for MSM. Crowdsourced interventions may be an important tool for the scale-up of HIV testing services among MSM in low- and middle-income countries (LMIC).

Trial registration

ClinicalTrials.gov NCT02796963

Relationship between very low low-density lipoprotein cholesterol concentrations not due to statin therapy and risk of type 2 diabetes: A US-based cross-sectional observational study using electronic health records

PLoS Medicine - Ma, 28/08/2018 - 22:00

by QiPing Feng, Wei-Qi Wei, Cecilia P. Chung, Rebecca T. Levinson, Alexandra C. Sundermann, Jonathan D. Mosley, Lisa Bastarache, Jane F. Ferguson, Nancy J. Cox, Dan M. Roden, Joshua C. Denny, MacRae F. Linton, Digna R. Velez Edwards, C. Michael Stein

Background

Observations from statin clinical trials and from Mendelian randomization studies suggest that low low-density lipoprotein cholesterol (LDL-C) concentrations may be associated with increased risk of type 2 diabetes mellitus (T2DM). Despite the findings from statin clinical trials and genetic studies, there is little direct evidence implicating low LDL-C concentrations in increased risk of T2DM.

Methods and findings

We used de-identified electronic health records (EHRs) at Vanderbilt University Medical Center to compare the risk of T2DM in a cross-sectional study among individuals with very low (≤60 mg/dl, N = 8,943) and normal (90–130 mg/dl, N = 71,343) LDL-C levels calculated using the Friedewald formula. LDL-C levels associated with statin use, hospitalization, or a serum albumin level < 3 g/dl were excluded. We used a 2-phase approach: in 1/3 of the sample (discovery) we used T2DM phenome-wide association study codes (phecodes) to identify cases and controls, and in the remaining 2/3 (validation) we identified T2DM cases and controls using a validated algorithm. The analysis plan for the validation phase was constructed at the time of the design of that component of the study. The prevalence of T2DM in the very low and normal LDL-C groups was compared using logistic regression with adjustment for age, race, sex, body mass index (BMI), high-density lipoprotein cholesterol, triglycerides, and duration of care. Secondary analyses included prespecified stratification by sex, race, BMI, and LDL-C level. In the discovery cohort, phecodes related to T2DM were significantly more frequent in the very low LDL-C group. In the validation cohort (N = 33,039 after applying the T2DM algorithm to identify cases and controls), the risk of T2DM was increased in the very low compared to normal LDL-C group (odds ratio [OR] 2.06, 95% CI 1.80–2.37; P < 2 × 10−16). The findings remained significant in sensitivity analyses. The association between low LDL-C levels and T2DM was significant in males (OR 2.43, 95% CI 2.00–2.95; P < 2 × 10−16) and females (OR 1.74, 95% CI 1.42–2.12; P = 6.88 × 10−8); in normal weight (OR 2.18, 95% CI 1.59–2.98; P = 1.1× 10−6), overweight (OR 2.17, 95% CI 1.65–2.83; P = 1.73× 10−8), and obese (OR 2.00, 95% CI 1.65–2.41; P = 8 × 10−13) categories; and in individuals with LDL-C < 40 mg/dl (OR 2.31, 95% CI 1.71–3.10; P = 3.01× 10−8) and LDL-C 40–60 mg/dl (OR 1.99, 95% CI 1.71–2.32; P < 2.0× 10−16). The association was significant in individuals of European ancestry (OR 2.67, 95% CI 2.25–3.17; P < 2 × 10−16) but not in those of African ancestry (OR 1.09, 95% CI 0.81–1.46; P = 0.56). A limitation was that we only compared groups with very low and normal LDL-C levels; also, since this was not an inception cohort, we cannot exclude the possibility of reverse causation.

Conclusions

Very low LDL-C concentrations occurring in the absence of statin treatment were significantly associated with T2DM risk in a large EHR population; this increased risk was present in both sexes and all BMI categories, and in individuals of European ancestry but not of African ancestry. Longitudinal cohort studies to assess the relationship between very low LDL-C levels not associated with lipid-lowering therapy and risk of developing T2DM will be important.

Influence of puberty timing on adiposity and cardiometabolic traits: A Mendelian randomisation study

PLoS Medicine - Ma, 28/08/2018 - 22:00

by Joshua A. Bell, David Carslake, Kaitlin H. Wade, Rebecca C. Richmond, Ryan J. Langdon, Emma E. Vincent, Michael V. Holmes, Nicholas J. Timpson, George Davey Smith

Background

Earlier puberty is widely linked with future obesity and cardiometabolic disease. We examined whether age at puberty onset likely influences adiposity and cardiometabolic traits independent of childhood adiposity.

Methods and findings

One-sample Mendelian randomisation (MR) analyses were conducted on up to 3,611 white-European female and male offspring from the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort recruited at birth via mothers between 1 April 1991 and 31 December 1992. Time-sensitive exposures were age at menarche and age at voice breaking. Outcomes measured at age 18 y were body mass index (BMI), dual-energy X-ray absorptiometry–based fat and lean mass indices, blood pressure, and 230 cardiometabolic traits derived from targeted metabolomics (150 concentrations plus 80 ratios from nuclear magnetic resonance [NMR] spectroscopy covering lipoprotein subclasses of cholesterol and triglycerides, amino acids, inflammatory glycoproteins, and others). Adjustment was made for pre-pubertal BMI measured at age 8 y. For negative control MR analyses, BMI and cardiometabolic trait measures taken at age 8 y (before puberty, and which therefore cannot be an outcome of puberty itself) were used. For replication analyses, 2-sample MR was conducted using summary genome-wide association study data on up to 322,154 adults for post-pubertal BMI, 24,925 adults for post-pubertal NMR cardiometabolic traits, and 13,848 children for pre-pubertal obesity (negative control). Like observational estimates, 1-sample MR estimates in ALSPAC using 351 polymorphisms for age at menarche (explaining 10.6% of variance) among 2,053 females suggested that later age at menarche (per year) was associated with −1.38 kg/m2 of BMI at age 18 y (or −0.34 SD units, 95% CI −0.46, −0.23; P = 9.77 × 10−09). This coefficient attenuated 10-fold upon adjustment for BMI at age 8 y, to −0.12 kg/m2 (or −0.03 SDs, 95% CI −0.13, 0.07; P = 0.55). Associations with blood pressure were similar, but associations across other traits were small and inconsistent. In negative control MR analyses, later age at menarche was associated with −0.77 kg/m2 of pre-pubertal BMI measured at age 8 y (or −0.39 SDs, 95% CI −0.50, −0.29; P = 6.28 × 10−13), indicating that variants influencing menarche also influence BMI before menarche. Cardiometabolic trait associations were weaker and less consistent among males and both sexes combined. Higher BMI at age 8 y (per 1 kg/m2 using 95 polymorphisms for BMI explaining 3.4% of variance) was associated with earlier menarche among 2,648 females (by −0.26 y, 95% CI −0.37, −0.16; P = 1.16 × 10−06), likewise among males and both sexes combined. In 2-sample MR analyses using 234 polymorphisms and inverse variance weighted (IVW) regression, each year later age at menarche was associated with −0.81 kg/m2 of adult BMI (or −0.17 SD units, 95% CI −0.21, −0.12; P = 4.00 × 10−15). Associations were weaker with cardiometabolic traits. Using 202 polymorphisms, later menarche was associated with lower odds of childhood obesity (IVW-based odds ratio = 0.52 per year later, 95% CI 0.48, 0.57; P = 6.64 × 10−15). Study limitations include modest sample sizes for 1-sample MR, lack of inference to non-white-European populations, potential selection bias through modest completion rates of puberty questionnaires, and likely disproportionate measurement error of exposures by sex. The cardiometabolic traits examined were heavily lipid-focused and did not include hormone-related traits such as insulin and insulin-like growth factors.

Conclusions

Our results suggest that puberty timing has a small influence on adiposity and cardiometabolic traits and that preventive interventions should instead focus on reducing childhood adiposity.

Different scientific approaches are needed to generate stronger evidence for population health improvement

PLoS Medicine - Ma, 28/08/2018 - 22:00

by Martin White, Jean Adams

In a Perspective, Martin White and Jean Adams discuss challenges in the evaluation of interventions intended to benefit population health.

Facebook bans Myanmar’s military leader in unprecedented move

New Scientist - Ma, 28/08/2018 - 17:34
Facebook has banned top military accounts in Myanmar, including the commander-in-chief's. This is the first time it has banned a country's military or political leaders

We dream even when under general anaesthetic

New Scientist - Ma, 28/08/2018 - 16:00
When we're under general anaesthesia, we are still internally conscious and we even have dreams, but we don't remember them because anaesthesia gives us amnesia

[Comment] Diagnosing myocardial infarction: a highly sensitive issue

The Lancet - Ma, 28/08/2018 - 13:30
The advent of high-sensitivity troponin assays to enable the quantification of troponin concentration in up to 95% of the general population is thought to improve clinical care in patients presenting with suspected infarction.1,2 The application of high-sensitivity troponin assays could be beneficial by enabling the early ruling out of myocardial infarction on the basis of very low troponin concentrations;3–7 precise and rapid diagnosis of myocardial infarction on the basis of troponin-based algorithms8,9 followed by early treatment initiation; and improved risk stratification on the basis of low troponin concentrations that are only detectable by high-sensitivity assays.

[Comment] Imaging of coronary inflammation for cardiovascular risk prediction

The Lancet - Ma, 28/08/2018 - 13:30
Inflammation plays an important part in the development of atherosclerosis and is a predictor of cardiovascular disease manifestation.1 Although circulating biomarkers of inflammation—eg, high sensitivity C-reactive protein—are associated with cardiovascular risk, they might not adequately reflect inflammatory activity in the coronary arteries at the individual patient level. Epicardial and perivascular adipose tissue—surrounding the heart and coronary arteries—secretes proinflammatory and anti-inflammatory cytokines and chemokines locally, and these tissues are associated with the extent and progression of coronary atherosclerosis and hard coronary events.

[Articles] High-sensitivity troponin in the evaluation of patients with suspected acute coronary syndrome: a stepped-wedge, cluster-randomised controlled trial

The Lancet - Ma, 28/08/2018 - 13:30
Use of a high-sensitivity assay prompted reclassification of 1771 (17%) of 10 360 patients with myocardial injury or infarction, but was not associated with a lower subsequent incidence of myocardial infarction or cardiovascular death at 1 year. Our findings question whether the diagnostic threshold for myocardial infarction should be based on the 99th centile derived from a normal reference population.

[Articles] Non-invasive detection of coronary inflammation using computed tomography and prediction of residual cardiovascular risk (the CRISP CT study): a post-hoc analysis of prospective outcome data

The Lancet - Ma, 28/08/2018 - 13:30
The perivascular FAI enhances cardiac risk prediction and restratification over and above current state-of-the-art assessment in coronary CTA by providing a quantitative measure of coronary inflammation. High perivascular FAI values (cutoff ≥–70·1 HU) are an indicator of increased cardiac mortality and, therefore, could guide early targeted primary prevention and intensive secondary prevention in patients.

[Comment] BASKET-SMALL 2: advancing DCB beyond in-stent restenosis

The Lancet - Ma, 28/08/2018 - 10:15
Drug-coated balloons (DCB) were first used as a new therapeutic option in the treatment of in-stent restenosis, with proven inhibition of restenosis in clinical studies.1–3 DCB have received a class 1 indication in the 2014 European Society of Cardiology guidelines4 for the treatment of both bare metal stent (BMS) and drug-eluting stent (DES) in-stent restenosis. The next question is whether DCB are effective in de-novo coronary lesions, specifically in small coronary vessels.

[Articles] Drug-coated balloons for small coronary artery disease (BASKET-SMALL 2): an open-label randomised non-inferiority trial

The Lancet - Ma, 28/08/2018 - 10:15
In small native coronary artery disease, DCB was non-inferior to DES regarding MACE up to 12 months, with similar event rates for both treatment groups.

Genoan bridge collapse shows the importance of structural redundancy

New Scientist - Ma, 28/08/2018 - 10:00
Signs Genoa’s Morandi motorway bridge needed repair were ignored or missed, but its initial structure didn’t have enough built-in fail-safes anyway
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