444 research outputs found

    A cohort study of the service-users of online contraception.

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    BACKGROUND: In January 2017, the first free service providing oral contraceptive pills (OCPs) ordered online and posted home became available in the London boroughs of Lambeth and Southwark - ethnically and socioeconomically diverse areas with high rates of unplanned pregnancy. There are concerns that online services can increase health inequalities; therefore, we aimed to describe service-users according to age, ethnicity and Index of Multiple Deprivation (IMD) quintile of area of residence and to examine the association of these with repeated use. METHODS: We analysed routinely collected data from January 2017 to April 2018 and described service-users using available sociodemographic factors and information on patterns of use. Logistic regression analysis examined factors associated with repeat ordering of OCPs. RESULTS: The service was accessed by 726 individuals; most aged between 20 and 29 years (72.5%); self-identified as being of white ethnic group (58.8%); and residents of the first and second most deprived IMD quintiles (79.2%). Compared with those of white ethnic group, those of black ethnic group were significantly less likely to make repeat orders (adjusted OR 0.53, 95% CI 0.31 to 0.89; p=0.001), as were those of Asian and mixed ethnic groups. CONCLUSIONS: These are the first empirical findings on free, online contraception and suggest that early adopters broadly reflect the population of the local area in terms of ethnic diversity and deprivation as measured by IMD. Ongoing service development should prioritise the identification and removal of barriers which may inhibit repeat use for black and minority ethnic groups

    Geospatial simulations of airborne ice-penetrating radar surveying reveal elevation under-measurement bias for ice-sheet bed topography

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    © The Author(s), 2020. Published by Cambridge University Press. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/).Airborne radio-echo sounding (RES) surveys are widely used to measure ice-sheet bed topography. Measuring bed topography as accurately and widely as possible is of critical importance to modelling ice dynamics and hence to constraining better future ice response to climate change. Measurement accuracy of RES surveys is influenced both by the geometry of bed topography and the survey design. Here we develop a novel approach for simulating RES surveys over glaciated terrain, to quantify the sensitivity of derived bed elevation to topographic geometry. Furthermore, we investigate how measurement errors influence the quantification of glacial valley geometry. We find a negative bias across RES measurements, where off-nadir return measurement error is typically -1.8 ± 11.6 m. Topographic highlands are under-measured an order of magnitude more than lowlands. Consequently, valley depth and cross-sectional area are largely under-estimated. While overall estimates of ice thickness are likely too high, we find large glacier valley cross-sectional area to be under-estimated by -2.8 ± 18.1%. Therefore, estimates of ice flux through large outlet glaciers are likely too low when this effect is not taken into account. Additionally, bed mismeasurements potentially impact our appreciation of outlet-glacier stability.Peer reviewedFinal Published versio

    Changes in, and factors associated with, frequency of sex in Britain: evidence from three National Surveys of Sexual Attitudes and Lifestyles (Natsal).

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    OBJECTIVES: To examine changes over time in the reported frequency of occurrence of sex and associations between sexual frequency and selected variables. DESIGN: Repeat, cross sectional, population based National Surveys of Sexual Attitudes and Lifestyles (Natsal-1, Natsal-2, and Natsal-3). SETTING: British general population. PARTICIPANTS: 18 876 men and women aged 16-59 and resident in Britain were interviewed in Natsal-1, completed in 1991; 11 161 aged 16-44 years in Natsal-2, completed in 2001, and 15 162 aged 16-74 years in Natsal-3, completed in 2012. Comparisons of actual and preferred sexual frequency in men and women aged 16-44 (the age range common to all surveys) between the three surveys. Factors associated with sexual frequency of at least once a week were examined using Natsal-3 data. MAIN OUTCOME MEASURES: Sexual activity in the past month; frequency of sex in the past month; preferred frequency of sex. RESULTS: Median number of occasions of sex in the past month was four in Natsal-1 and Natsal-2 and three in Natsal-3 among women; and three in Natsal-1, Natsal-2, and Natsal-3 among men. The proportion reporting no sex in the past month fell between Natsal-1 and Natsal-2 (from 28.5% to 23.0% in women and from 30.9% to 26.0% in men) but increased significantly in Natsal-3 (to 29.3% in women and 29.2% in men). The proportion reporting sex 10 times or more in the past month increased between Natsal-1 and Natsal-2, from 18.4% to 20.6% in women and from 19.9% to 20.2% in men, but fell in Natsal-3, to 13.2% in woman and 14.4% in men. Participants aged 25 and over, and those married or cohabiting, experienced the steepest declines in sexual frequency (P values for interaction <0.05). Alongside the declines in sexual frequency, there was an increase in the proportion reporting that they would prefer sex more often. Age adjusted odds ratios showed that men and women in better physical and mental health had sex more frequently, as did those who were fully employed and those with higher earnings. CONCLUSIONS: Frequency of sex has declined recently in Britain, more markedly among those in early middle age and those who are married or cohabiting. The findings and their implications need to be explained in the context of technological, demographic, and social change in Britain and warrant further investigation

    Trends in sexual activity and demand for and use of modern contraceptive methods in 74 countries: a retrospective analysis of nationally representative surveys.

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    BACKGROUND: A quarter of a century ago, two global events-the International Conference on Population and Development in Cairo, and the Fourth World Conference on Women in Beijing-placed gender equality and reproductive health and rights at the centre of the development agenda. Progress towards these goals has been slower than hoped. We used survey data and national-level indicators of social determinants from 74 countries to examine change in satisfaction of contraceptive need from a contextual perspective. METHODS: We searched for individual-level data from repeated nationally representative surveys that included information on sexual and reproductive health, and created a single dataset by harmonising data from each survey to a standard data specification. We described the relative timings of sexual initiation, first union (cohabitation or marriage), and first birth and used logistic regression to show the change in prevalence of sexual activity, demand for contraception, and modern contraceptive use. We used linear regression to examine country-level associations between the gender development index and the expected length of time in education for women and the three outcomes: sexual activity, demand for contraception, and modern contraceptive use. We used principal component analysis to describe countries using a combination of social-structural and behavioural indicators and assessed how well the components explained country-level variation in the proportion of women using contraception with fractional logistic regression. FINDINGS: In 34 of the 74 countries examined, proportions of all women who were sexually active, not wanting to conceive, and not using a modern contraceptive method decreased over time. Proportions of women who had been sexually active in the past year changed over time in 43 countries, with increases in 30 countries; demand for contraception increased in 42 countries, and use of a modern method of contraception increased in 37 countries. Increases over time in met need for contraception were correlated with increases in gender equality and with women's time in education. Regression analysis on the principal components showed that country-level variation in met contraceptive need was largely explained by a single component that combined behavioural and social-contextual variables. INTERPRETATION: Progress towards satisfying demand for contraception should take account of the changing context in which it is practised. To remove the remaining barriers, policy responses-and therefore research priorities-could require a stronger focus on social-structural determinants and broader aspects of sexual health. FUNDING: UNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction

    Interpretation of psychiatric genome-wide association studies with multispecies heterogeneous functional genomic data integration.

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    Genome-wide association studies and other discovery genetics methods provide a means to identify previously unknown biological mechanisms underlying behavioral disorders that may point to new therapeutic avenues, augment diagnostic tools, and yield a deeper understanding of the biology of psychiatric conditions. Recent advances in psychiatric genetics have been made possible through large-scale collaborative efforts. These studies have begun to unearth many novel genetic variants associated with psychiatric disorders and behavioral traits in human populations. Significant challenges remain in characterizing the resulting disease-associated genetic variants and prioritizing functional follow-up to make them useful for mechanistic understanding and development of therapeutics. Model organism research has generated extensive genomic data that can provide insight into the neurobiological mechanisms of variant action, but a cohesive effort must be made to establish which aspects of the biological modulation of behavioral traits are evolutionarily conserved across species. Scalable computing, new data integration strategies, and advanced analysis methods outlined in this review provide a framework to efficiently harness model organism data in support of clinically relevant psychiatric phenotypes

    Contraception in Person-Contraception Online (CiP-CO) cohort study.

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    BACKGROUND: Online contraception services increasingly provide information, clinical assessment and home-delivered oral contraceptives (OCs). Evidence is lacking on the effects of online contraceptive service use on short-term contraceptive continuation. METHODS: Cohort study comparing contraceptive continuation between new users of a free-to-access online OC service in South East London with those from other, face-to-face services in the same area. Online questionnaires collected data on participants' sociodemographic characteristics, motivations for OC access, service ratings, OC knowledge and contraceptive use. Contraceptive use in the 4-month study period was measured using health service records. Unadjusted and multivariable logistic regression models compared outcomes between the online service group and those using other services. RESULTS: Online service-users (n=138) were more likely to experience short-term continuation of OCs compared with participants using other services (n=98) after adjusting for sociodemographic and other characteristics (adjusted OR 2.94, 95% CI 1.52 to 5.70). Online service-users rated their service more highly (mean 25.22, SD 3.77) than the other services group (mean 22.70, SD 4.35; p<0.001), valuing convenience and speed of access. Among progestogen-only pill users, knowledge scores were higher for the online group (mean 4.83, SD 1.90) than the other services group (mean 3.87, SD 1.73; p=0.007). Among combined oral contraceptive users, knowledge scores were similar between groups. CONCLUSIONS: Free-to-access, online contraception has the potential to improve short-term continuation of OCs. Further research using a larger study population and analysis of longer-term outcomes are required to understand the impact of online services on unintended pregnancy

    Aβ degradation or cerebral perfusion? Divergent effects of multifunctional enzymes:Divergent effects of multifunctional enzymes

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    There is increasing evidence that deficient clearance of β-amyloid (Aβ) contributes to its accumulation in late-onset Alzheimer disease (AD). Several Aβ-degrading enzymes, including neprilysin (NEP), endothelin-converting enzyme (ECE), and angiotensin-converting enzyme (ACE) reduce Aβ levels and protect against cognitive impairment in mouse models of AD. In post-mortem human brain tissue we have found that the activity of these Aβ-degrading enzymes rise with age and increases still further in AD, perhaps as a physiological response that helps to minimize the build-up of Aβ. ECE-1/-2 and ACE are also rate-limiting enzymes in the production of endothelin-1 (ET-1) and angiotensin II (Ang II), two potent vasoconstrictors, increases in the levels of which are likely to contribute to reduced blood flow in AD. This review considers the possible interdependence between Aβ-degrading enzymes, ischemia and Aβ in AD: ischemia has been shown to increase Aβ production both in vitro and in vivo, whereas increased Aβ probably enhances ischemia by vasoconstriction, mediated at least in part by increased ECE and ACE activity. In contrast, NEP activity may help to maintain cerebral perfusion, by reducing the accumulation of Aβ in cerebral blood vessels and lessening its toxicity to vascular smooth muscle cells. In assessing the role of Aβ-degrading proteases in the pathogenesis of AD and, particularly, their potential as therapeutic agents, it is important to bear in mind the multifunctional nature of these enzymes and to consider their effects on other substrates and pathways

    Sexual health interventions delivered to participants by mobile technology: a systematic review and meta-analysis of randomised controlled trials.

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    BACKGROUND: The use of mobile technologies to prevent STIs is recognised as a promising approach worldwide; however, evidence has been inconclusive, and the field has developed rapidly. With about 1 million new STIs a day globally, up-to-date evidence is urgently needed. OBJECTIVE: To assess the effectiveness of mobile health interventions delivered to participants for preventing STIs and promoting preventive behaviour. METHODS: We searched seven databases and reference lists of 49 related reviews (January 1990-February 2020) and contacted experts in the field. We included randomised controlled trials of mobile interventions delivered to adolescents and adults to prevent sexual transmission of STIs. We conducted meta-analyses and assessed risk of bias and certainty of evidence following Cochrane guidance. RESULTS: After double screening 6683 records, we included 22 trials into the systematic review and 20 into meta-analyses; 18 trials used text messages, 3 used smartphone applications and 1 used Facebook messages as delivery modes. The certainty of evidence regarding intervention effects on STI/HIV occurrence and adverse events was low or very low. There was moderate certainty of evidence that in the short/medium-term text messaging interventions had little or no effect on condom use (standardised mean differences (SMD) 0.02, 95% CI -0.09 to 0.14, nine trials), but increased STI/HIV testing (OR 1.83, 95% CI 1.41 to 2.36, seven trials), although not if the standard-of-care control already contained an active text messaging component (OR 1.00, 95% CI 0.68 to 1.47, two trials). Smartphone application messages also increased STI/HIV testing (risk ratio 1.40, 95% CI 1.22 to 1.60, subgroup analysis, two trials). The effects on other outcomes or of social media or blended interventions is uncertain due to low or very low certainty evidence. CONCLUSIONS: Text messaging interventions probably increase STI/HIV testing but not condom use in the short/medium term. Ongoing trials will report the effects on biological and other outcomes
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