271 research outputs found
A DIET ENRICHED IN STEARIC ACID PROTECTS AGAINST THE PROGRESSION OF TYPE 2 DIABETES IN LEPTIN RECEPTOR DEFICIENT MICE (DB/DB)
Dietary saturated fat intake contributes to diabetes and cardiovascular disease, as shown in numerous animal and human studies. However, the hypothesis that stearic acid, a saturated fat, has beneficial effects on these conditions has not been adequately tested. Leptin receptor deficient mice (db/db) and wild-type mice were fed either chow or a high fat diet enriched in either stearic acid or oleic acid for ten weeks. The progression of diabetes was evaluated with blood glucose, insulin, and metabolic parameter measurements. At the conclusion of the study, pancreatic islet organization was examined, and blood, liver and feces were assayed for fatty acid content.
The stearic acid enriched diet prevented increases in blood glucose levels independently of weight loss in db/db mice compared to an oleic acid or chow diet. Diabetic mice fed stearic acid maintained insulin responsiveness and pancreatic islet organization compared to the db/db mice fed chow and oleic diets. The islet organization of the stearic acid fed mice did not change over the course of the study and was similar to that of wild-type mice fed the same diet. Conversely, diabetic mice fed oleic acid and chow diets had decreased insulin responsiveness and disorganized islets. Stearic acid fed db/db mice had high fecal fat content and caloric intake calculations indicated low absorption of this fat.
Switching to stearic acid after prolonged hyperglycemia had a rescue effect on blood glucose levels. After feeding diabetic and wild-type mice standard chow diets for 6, 8, and 10 weeks to establish hyperglycemia, mice switched to a high fat diet enriched in stearic acid, but not one enriched in oleic acid diet, had significant reductions in blood glucose levels.
The ability of a stearic acid enriched high fat diet to slow the progression of diabetes and reverse hyperglycemia in db/db mice argues that risks and benefits of fats in the diet depend on the chemical structure, rather than the chemical class, of fats ingested. The beneficial effect of stearic acid appears to be associated with a decreased absorption of dietary fat
A Productive Relationship? Testing the Connections between Professional Learning and Practitioner Research
This article is written in response to a recent report on a review of teacher education in Scotland undertaken by Graham Donaldson (2010). In particular it questions the recommendation that engaging teachers in professional enquiry and research-informed teaching is the way forward for developing the professional capabilities required of "21st Century teachers". The report reflects an increasing emphasis in the literature on school effectiveness and improvement of the need to further teachers' professional learning and of a pedagogic pressure for equipping them to adopt constructivist approaches to teaching that are based on research evidence about how children and young people learn best. Practitioner research is seen by policy makers as an important strategy for achieving these objectives. This article, based on a series of empirical studies, sets out to identify some of the issues revealed by the attempt to use practitioner research as a vehicle for affecting classroom practice within the context of a policy initiative to support the development of accomplished teaching. It argues that, if such a strategy is to be effective, it is important to conceive of it in systemic terms and to confront the challenges involved in developing the sets of networked relations that will be essential if such a strategy is to prove worthwhile
The rise of hunger among low-income households: an analysis of the risks of food insecurity between 2004 and 2016 in a population-based study of UK adults
Background: Rising food bank use in the past decade in the UK raises questions about whether food insecurity has increased. Using the 2016 Food and You survey, we describe the magnitude and severity of the problem, examine characteristics associated with severity of food insecurity, and examine how vulnerability has changed among low-income households by comparing 2016 data to the 2004 Low Income Diet and Nutrition Survey. Methods: The Food and You survey is a representative survey of adults living in England, Wales, and Northern Ireland (n=3118). Generalised ordered logistic regression models were used to examine how socioeconomic characteristics related to severity of food insecurity. Coarsened exact matching was used to match respondents to respondents in the 2004 survey. Logistic regression models were used to examine if food insecurity rose between survey years. Results: 20.7% (95% CI 18.7% to 22.8%) of adults experienced food insecurity in 2016, and 2.72% (95% CI 2.07% to 3.58%) were severely food insecure. Younger age, non-white ethnicity, low education, disability, unemployment, and low income were all associated with food insecurity, but only the latter three characteristics were associated with severe food insecurity. Controlling for socioeconomic variables, the probability of low-income adults being food insecure rose from 27.7% (95% CI 24.8% to 30.6 %) in 2004 to 45.8% (95% CI 41.6% to 49.9%) in 2016. The rise was most pronounced for people with disabilities. Conclusions: Food insecurity affects economically deprived groups in the UK, but unemployment, disability and low income are characteristics specifically associated with severe food insecurity. Vulnerability to food insecurity has worsened among low-income adults since 2004, particularly among those with disabilities
Family policy and food insecurity: an observational analysis in 142 countries
Background: Levels of child malnutrition and hunger across the world have decreased substantially over the past century, and this has had an important role in reducing mortality and improving health. However, progress has stalled. We examined whether family policies (eg, cash transfers from governments that aim to support households with children) are associated with reduced food insecurity. Methods: In this observational analysis, we used a dataset of individual-level data that captured experience-based measures of food insecurity and sociodemographic characteristics collected by the Gallup World Poll in 142 countries for 2014–17. We then combined this dataset with indicators of the type and generosity of family policies in these countries, taken from the University of California, Los Angeles’ World Policy Analysis Center. We used multilevel regression models to examine the association between the presence of family policies for households with children and the probability of reporting moderate or severe food insecurity or severe food insecurity (moderate or severe food insecurity was defined as a “yes” response to at least four of eight questions on the Gallup Food Insecurity Experience Scale, and severe food insecurity was defined as a “yes” response to at least seven questions). We controlled for multiple covariates, including individual-level measures of social position and country-level measures, such as gross domestic product. We further examined whether this association varied by household income level. Findings: Using data from 503 713 households, we found that, on average, moderate or severe food insecurity is 4·09 percentage points (95% CI 3·50–4·68) higher in households with at least one child younger than 15 years than in households with no children and severe food insecurity is 2·20 percentage points (1·76–2·63) higher. However, the additional risk of food insecurity among households with children is lower in countries that provide financial support (either means-tested or universal) for families than for countries with little or no financial assistance. These policies not only reduce food insecurity on average, but they also reduce inequalities in food insecurity by benefiting the poorest households most. Interpretation: In some countries, family policies have been cut back in the past decade and such retrenchment might expose low-income households to increased risk of food insecurity. By increasing investment in family policies, progress towards Sustainable Development Goal 2, zero hunger, might be accelerated and, in turn, improve health for all. Funding: Wellcome Trust
Reported frequency of physical activity in a large epidemiological study: relationship to specific activities and repeatability over time
BACKGROUND How overall physical activity relates to specific activities and how reported activity changes over time may influence interpretation of observed associations between physical activity and health. We examine the relationships between various physical activities self-reported at different times in a large cohort study of middle-aged UK women. METHODS At recruitment, Million Women Study participants completed a baseline questionnaire including questions on frequency of strenuous and of any physical activity. About 3 years later 589,896 women also completed a follow-up questionnaire reporting the hours they spent on a range of specific activities. Time spent on each activity was used to estimate the associated excess metabolic equivalent hours (MET-hours) and this value was compared across categories of physical activity reported at recruitment. Additionally, 18,655 women completed the baseline questionnaire twice, at intervals of up to 4 years; repeatability over time was assessed using the weighted kappa coefficient (κweighted) and absolute percentage agreement. RESULTS The average number of hours per week women reported doing specific activities was 14.0 for housework, 4.5 for walking, 3.0 for gardening, 0.2 for cycling, and 1.4 for all strenuous activity. Time spent and the estimated excess MET-hours associated with each activity increased with increasing frequency of any or strenuous physical activity reported at baseline (tests for trend, P < 0.003), although the associations for housework were by far the weakest (Spearman correlations, 0.01 and -0.03 respectively for housework, and 0.11-0.37 for all other activities). Repeatability of responses to physical activity questions on the baseline questionnaire declined significantly over time. For strenuous activity, absolute agreement was 64% (κweighted = 0.71) for questionnaires administered less than 6 months apart, and 52% (κweighted = 0.51) for questionnaires more than 2 years apart. Corresponding values for any physical activity were 57% (κweighted = 0.67) and 47% (κweighted = 0.58). CONCLUSIONS In this cohort, responses to simple questions on the frequency of any physical activity and of strenuous activity asked at baseline were associated with hours spent on specific activities and the associated estimated excess MET-hours expended, reported 3 years later. The weakest associations were with housework. Agreement for identical questions asked on two occasions about the frequency of physical activity decreased over time.This work was supported by public funds from Cancer
Research UK and the UK Medical Research Council
Body mass index and incident coronary heart disease in women: a population-based prospective study
BACKGROUND A high body mass index (BMI) is associated with an increased risk of mortality from coronary heart disease (CHD); however, a low BMI may also be associated with an increased mortality risk. There is limited information on the relation of incident CHD risk across a wide range of BMI, particularly in women. We examined the relation between BMI and incident CHD overall and across different risk factors of the disease in the Million Women Study. METHODS 1.2 million women (mean age=56 years) participants without heart disease, stroke, or cancer (except non-melanoma skin cancer) at baseline (1996 to 2001) were followed prospectively for 9 years on average. Adjusted relative risks and 20-year cumulative incidence from age 55 to 74 years were calculated for CHD using Cox regression. RESULTS After excluding the first 4 years of follow-up, we found that 32,465 women had a first coronary event (hospitalization or death) during follow-up. The adjusted relative risk for incident CHD per 5 kg/m2 increase in BMI was 1.23 (95% confidence interval (CI) 1.22 to 1.25). The cumulative incidence of CHD from age 55 to 74 years increased progressively with BMI, from 1 in 11 (95% CI 1 in 10 to 12) for BMI of 20 kg/m2, to 1 in 6(95% CI 1 in 5 to 7) for BMI of 34 kg/m2. A 10 kg/m2 increase in BMI conferred a similar risk to a 5-year increment in chronological age. The 20 year cumulative incidence increased with BMI in smokers and non-smokers, alcohol drinkers and non-drinkers, physically active and inactive, and in the upper and lower socioeconomic classes. In contrast to incident disease, the relation between BMI and CHD mortality (n=2,431) was J-shaped. For the less than 20 kg/m2 and ≥35 kg/m2 BMI categories, the respective relative risks were 1.27 (95% CI 1.06 to 1.53) and 2.84 (95% CI 2.51 to 3.21) for CHD deaths, and 0.89 (95% CI 0.83 to 0.94) and 1.85 (95% CI 1.78 to 1.92) for incident CHD. CONCLUSIONS CHD incidence in women increases progressively with BMI, an association consistently seen in different subgroups. The shape of the relation with BMI differs for incident and fatal disease.The Million Women Study is funded by Cancer Research UK, the Medical
Research Council, and the NHS Breast Screening Programme. The funding
organizations were not involved in the study design or conduct, data
analysis or interpretation, manuscript preparation or review, final version
approval, or decision to submit the manuscript
Liberal trade policy and food insecurity across the income distribution: an observational analysis in 132 countries, 2014–17
Background: Eradicating food insecurity is necessary for achieving global health goals. Liberal trade policies might increase food supplies but how these policies influence individual-level food insecurity remains uncertain. We aimed to assess the association between liberal trade policies and food insecurity at the individual level, and whether this association varies across country-income and household-income groups. Methods: For this observational analysis, we combined individual-level data from the Food and Agricultural Organization of the UN with a country-level trade policy index from the Konjunkturforschungsstelle Swiss Economic Institute. We examined the association between a country's trade policy score and the probability of individuals reporting moderate-severe or severe food insecurity using regression models and algorithmic weighting procedures. We controlled for multiple covariates, including gross domestic product, democratisation level, and population size. Additionally, we examined heterogeneity by country and household income. Results: Our sample comprised 460 102 individuals in 132 countries for the period of 2014–17. Liberal trade policy was not significantly associated with moderate-severe or severe food insecurity after covariate adjustment. However, among households in high-income countries with incomes higher than US450 per person per year) in low-income countries, a unit increase in the trade policy index was associated with a 0·35% (0·06 to 0·60) increase in the predicted probability of reporting moderate-severe food insecurity. Interpretation: The relationship between liberal trade policy and food insecurity varied across countries and households. Liberal trade policy was predominantly associated with lower food insecurity in high-income countries but corresponded to increased food insecurity among the world's poorest households in low-income countries. Funding: Joseph Rowntree Foundation, Economic and Social Research Council
Linear law for the logarithms of the Riemann periods at simple critical zeta zeros
Each simple zero 1/2 + iγn of the Riemann zeta function on the critical line with γn > 0 is a center for the flow s˙ = ξ(s) of the Riemann xi function with an associated period Tn. It is shown that, as γn →∞, log Tn ≥ π/4 γn + O(log γn).
Numerical evaluation leads to the conjecture that this inequality can be replaced by an equality. Assuming the Riemann Hypothesis and a zeta zero separation conjecture γn+1 − γn≥ γn-θ for some exponent θ > 0, we obtain the upper bound log Tn ≤ γn2 + θ Assuming a weakened form of a conjecture of Gonek, giving a bound for the reciprocal of the derivative of zeta at each zero, we obtain the expected upper bound for the periods so, conditionally, log Tn = π/ 4 γn +O(log γn). Indeed, this linear relationship is equivalent to the given weakened conjecture, which implies the zero separation conjecture, provided the exponent is sufficiently large. The frequencies corresponding to the periods relate to natural eigenvalues for the Hilbert–Polya conjecture. They may provide a goal for those seeking a self-adjoint operator related to the Riemann hypothesis
A Productive Relationship? Testing the Connections between
ABSTRACT This article is written in response to a recent report on a review of teacher education in Scotland undertaken by Graham Donaldson (2011). In particular it questions the recommendation that engaging teachers in professional enquiry and research-informed teaching is the way forward for developing the professional capabilities required of "21 st Century teachers". The report reflects an increasing emphasis in the literature on school effectiveness and improvement of the need to further teachers' professional learning and a pedagogic pressure for them to adopt constructivist approaches to teaching that are based on research evidence about how children and young people learn best. Practitioner research is seen by policy makers as an important strategy for achieving these objectives. This article, based on a series of empirical studies, sets out to identify some of the issues revealed by the attempt to use practitioner research as a vehicle for affecting classroom practice within the context of a policy initiative to support the development of accomplished teaching. It argues that, if such a strategy is to be effective, it is important to conceive of it in systemic terms and to confront the challenges involved in developing the sets of networked relations that will be essential if such a strategy is to prove worthwhile
Oral bisphosphonates and risk of cancer of oesophagus, stomach, and colorectum: case-control analysis within a UK primary care cohort
Objective To examine the hypothesis that risk of oesophageal, but not of gastric or colorectal, cancer is increased in users of oral bisphosphonates
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