Physical activity and mortality: is the association explained by genetic selection?

Public health recommendations promote physical activity to improve health and longevity. Recent data suggest that the association between physical activity and mortality may be due to genetic selection. Using data on twins, the authors investigated whether genetic selection explains the association between physical activity and mortality. Data were based on a postal questionnaire answered by 13,109 Swedish twin pairs in 1972. The national Cause of Death Register was used for information about all-cause mortality (n=1,800) and cardiovascular disease mortality (n=638) during 1975-2004. The risk of death was reduced by 34% for men (relative risk=0.64, 95% confidence interval: 0.50, 0.83) and by 25% for women (relative risk=0.75, 95% confidence interval: 0.50, 1.14) reporting high physical activity levels. Within-pair comparisons of monozygotic twins showed that, compared with their less active co-twin, the more active twin had a 20% (odds ratio=0.80, 95% confidence interval: 0.65, 0.99) reduced risk of all-cause mortality and a 32% (odds ratio=0.68, 95% confidence interval: 0.49, 0.95) reduced risk of cardiovascular disease mortality. Results indicate that physical activity is associated with a reduced risk of mortality not due to genetic selection. This finding supports a causal link between physical activity and mortality.     

Two-stage residual inclusion for survival data and competing risks—An instrumental variable approach with application to SEER-Medicare linked data

Instrumental variable is an essential tool for addressing unmeasured confounding in observational studies. Two-stage predictor substitution (2SPS) estimator and two-stage residual inclusion (2SRI) are two commonly used approaches in applying instrumental variables. Recently, 2SPS was studied under the additive hazards model in the presence of competing risks of time-to-events data, where linearity was assumed for the relationship between the treatment and the instrument variable. This assumption may not be the most appropriate when we have binary treatments. In this paper, we consider the 2SRI estimator under the additive hazards model for general survival data and in the presence of competing risks, which allows generalized linear models for the relation between the treatment and the instrumental variable. We derive the asymptotic properties including a closed-form asymptotic variance estimate for the 2SRI estimator. We carry out numerical studies in finite samples and apply our methodology to the linked Surveillance, Epidemiology and End Results (SEER)–Medicare database comparing radical prostatectomy versus conservative treatment in early-stage prostate cancer patients.     

Using Bayes model averaging to leverage both gene main effects and G × E interactions to identify genomic regions in genome-wide association studies

Genome-wide association studies typically search for marginal associations between a single-nucleotide polymorphism (SNP) and a disease trait while gene-environment (G × E) interactions remain generally unexplored. More powerful methods beyond the simple case–control (CC) approach leverage either marginal effects or CC ascertainment to increase power. However, these potential gains depend on assumptions whose aptness is often unclear a priori. Here, we review G × E methods and use simulations to highlight performance as a function of main and interaction effects and the association of the two factors in the source population. Substantial variation in performance between methods leads to uncertainty as to which approach is most appropriate for any given analysis. We present a framework that (a) balances the robustness of a CC approach with the power of the case-only (CO) approach; (b) incorporates main SNP effects; (c) allows for incorporation of prior information; and (d) allows the data to determine the most appropriate model. Our framework is based on Bayes model averaging, which provides a principled statistical method for incorporating model uncertainty. We average over inclusion of parameters corresponding to the main and G × E interaction effects and the G–E association in controls. The resulting method exploits the joint evidence for main and interaction effects while gaining power from a CO equivalent analysis. Through simulations, we demonstrate that our approach detects SNPs within a wide range of scenarios with increased power over current methods. We illustrate the approach on a gene-environment scan in the USC Children's Health Study.     

How much of the data published in observational studies of the association between diet and prostate or bladder cancer is usable for meta-analysis?

Epidemiologic investigations often report dose-response associations, which may be combined in meta-analyses. The authors examined how often the log odds, risk, or hazard ratio per unit increase in exposure, and its standard error, can be estimated from results reported from observational studies of diet and prostate or bladder cancer so that results are usable in meta-analyses estimating dose-response associations. Eight electronic databases were searched for studies reporting on the association of diet, nutrition, or physical activity with these cancers. A total of 767 papers reported 3,284 results; 1,999 (61%) results, reported in 545 (71%) papers, were usable in dose-response meta-analyses. The most important reason that results were not usable was the absence of sufficient information on exposure levels in the different groups. The proportion of results usable in "high-low" meta-analyses (comparisons of extreme categories) was similar (62%). Results that showed evidence of an association were more likely to be usable than results that found no such evidence. Insufficient detail in reporting of results of observational studies can lead to exclusion of these results from meta-analyses and is an important threat to the validity of systematic reviews of such research. Results providing evidence of associations may be overrepresented in meta-analyses of observational studies.     

A clearing house for diagnostic testing: the solution to ensure access to and use of patented genetic inventions?

In genetic diagnostics, the emergence of a so-called "patent thicket" is imminent. Such an overlapping set of patent rights may have restrictive effects on further research and development of diagnostic tests, and the provision of clinical diagnostic services. Currently, two models that may facilitate access to and use of patented genetic inventions are attracting much debate in various national and international fora: patent pools and clearing houses. In this article, we explore the concept of clearing houses. Several types of clearing houses are identified. First, we describe and discuss two types that would provide access to information on the patented inventions: the information clearing house and the technology exchange clearing house. Second, three types of clearing houses are analysed that not only offer access to information but also provide an instrument to facilitate the use of the patented inventions: the open access clearing house, the standardized licences clearing house and the royalty collection clearing house. A royalty collection clearing house for genetic diagnostic testing would be the most comprehensive as it would serve several functions: identifying patents and patent claims essential to diagnostic testing, matching licensees with licensors, developing and supplying standardized licences, collecting royalties, monitoring whether users respect licensing conditions, and providing dispute resolution services such as mediation and arbitration. In this way, it might function as an effective model for users to facilitate access to and use of the patented inventions. However, it remains to be seen whether patent holders with a strong patent portfolio will be convinced by the advantages of the royalty collection clearing house and be willing to participate.     

Patterns of alcohol drinking and its association with obesity: data from the third national health and nutrition examination survey, 1988–1994

Background  

Recent reports suggest that alcohol use may have a protective effect on obesity. This study explores association between obesity and alcohol consumption in the non-smoking U.S. adult population.     

Media content about vaccines in the United States and Canada, 2012–2014: An analysis using data from the Vaccine Sentimeter

BackgroundA system for monitoring vaccine-related media content was previously developed and studied from an international perspective. This monitoring approach could also have value at a regional level, but it has yet to be evaluated at this scale. We examined regional patterns of vaccine-related media topics and sentiment in the US and Canada.MethodsWe extracted vaccine-relevant US and Canadian online media reports between June 2012 and October 2014 from the Vaccine Sentimeter, a HealthMap-based automated media monitoring system for news aggregators and blogs. We analyzed regional distributions of reports about vaccines, categories (i.e., topics), sentiment, and measles outbreaks.FindingsThe Vaccine Sentimeter captured 10,715 reports during the study period. Negative sentiment was highest in reports about vaccine safety (47%), Hepatitis B (19%), and Vermont (18%). Analyses of measles outbreaks revealed geographical variation in media content. For example, religious beliefs were mentioned in 27% of measles reports in Texas and 22% of British Columbia reports, but there were no references to religion in media on measles from California.InterpretationsA regional analysis of online sentiment towards vaccine can provide insights that may give US and Canadian public health practitioners a deeper understanding of media influences on vaccine choices in their regions and consequently lead to more effective public health action.     

Global infant mortality trends and attributable determinants – an ecological study using data from 192 countries for the period 1990–2011

Background

Infant mortality rate (IMR) is regarded as an important indicator of population health. IMR rates vary substantially with the highest found in sub-Saharan Africa (SSA) compared to the lowest in Europe. Identifying spatial disparities in IMR and quantifying attributable risk factors is essential for policymakers when tailoring time-appropriate interventions at a global, regional, and country level.

Methods

Data for 192 countries were extracted from the World Bank Development Indicator database for the period 1990–2011. Spatial clustering was used to identify significant higher-risk IMR countries. A robust ecological generalized linear negative binomial regression model was used to quantify risk factors and associated decomposition values (Shapley).

Results

Significant reductions were observed in IMR for all of the World Health Organization regions for the period 1990–2011 except for SSA, which indicated a reversal of this trend in the 1990s due to HIV. Significant high-risk clustering of IMR is also indicated in SSA countries and parts of Asia. Maternal mortality (survival), lack of water and sanitation and female education were confirmed as prominent and high attributable risk factors for IMR. Distinct temporal changes in the attributability of these factors were observed, as well as significant heterogeneity with regards to the most attributable factor by region and country.

Conclusions

Our study suggests that maternal mortality is the most prominent attributable risk factor for infant mortality, followed by lack of access to sanitation, lack of access to water, and lower female education. Variation exists across regions and countries with regards to the most attributable factor. Our study also suggests significant underestimation of IMR in regions known for poorer data quality. The results will aid policymakers in re-tailoring time-appropriate interventions to more effectively reduce IMR in line with Millennium Development Goal 4.

     

Why invest in a national public health program for stroke?: An example using Australian data to estimate the potential benefits and cost implications

OBJECTIVES: Stroke is the world's second leading cause of death in people aged over 60 years. Approximately 50,000 strokes occur annually in Australia with numbers predicted to increase by about one third over 10-years. Our objectives were to assess the economic implications of a public health program for stroke by: (1) predicting what potential health-gains and cost-offsets could be achieved; and (2) determining the net level of annual investment that would offer value-for-money. METHODS: Lifetime costs and outcomes were calculated for additional cases that would benefit if 'current practice' was feasibly improved, estimated for one indicative year using: (i) local epidemiological data, coverage rates and costs; and (ii) pooled effect sizes from systematic reviews. Interventions: blood pressure lowering; warfarin for atrial fibrillation; increased access to stroke units; intravenous thrombolysis and aspirin for ischemic events; and carotid endarterectomy. Value-for-money threshold: AUD$30,000/DALY recovered. RESULTS: Improved, prevention and management could prevent about 27,000 (38%) strokes in 2015. In present terms (2004), about 85,000 DALYs and AUD$1.06 billion in lifetime cost-offsets could be recovered. The net level of annual warranted investment was AUD$3.63 billion. CONCLUSIONS: Primary prevention, in particular blood pressure lowering, was most effective. A public health program for stroke is warranted.     

Hospital admissions for asthma,diabetes and COPD: is there an association with practice nurse staffing? A cross sectional study using routinely collected data

Background  

Delivering good quality primary care for patients with chronic conditions has the potential to reduce non-elective hospital admissions. Practice nurse staffing levels in England have been linked to attainment of general practice performance targets for some chronic conditions. The aim of this study was to examine whether practice nurse staffing level is similarly associated with non-elective hospital admissions in three clinical areas: asthma, Chronic Obstructive Pulmonary Disease (COPD) and diabetes.     

‘I’m searching for solutions’: why are obese individuals turning to the Internet for help and support with ‘being fat’?

Introduction This study explores what types of information obese individuals search for on the Internet, their motivations for seeking information and how they apply it in their daily lives. Method In‐depth telephone interviews with an Australian community sample of 142 individuals with a BMI ≥ 30 were conducted. Theoretical, purposive and strategic samplings were employed. Data were analysed using a constant comparative method. Results Of the 142 individuals who participated in the study, 111 (78%) searched for information about weight loss or obesity. Of these, about three quarters searched for weight loss solutions. The higher the individual’s weight, the more they appeared to search for weight loss solutions. Participants also searched for information about health risks associated with obesity (n = 28), how to prevent poor health outcomes (n = 30) and for peer support forums with other obese individuals (n = 25). Whilst participants visited a range of websites, including government‐sponsored sites, community groups and weight loss companies, they overwhelmingly acted upon the advice given on commercial diet websites. However, safe, non‐judgemental spaces such as the Fatosphere (online fat acceptance community) provided much needed solidarity and support. Conclusions The Internet provides a convenient source of support and information for obese individuals. However, many turn to the same unsuccessful solutions online (e.g. fad dieting) they turn to in the community. Government and community organisations could draw upon some lessons learned in other consumer‐driven online spaces (e.g. the Fatosphere) to provide supportive environments for obese individuals that resonate with their health and social experiences, and address their needs.     

‘I’m not sure if they speak to everyone about this option’: analyzing disparate access to and use of genetic health services in the US from the perspective of genetic counselors

Much research has documented disparities in access to and uses of health care services in the US. With the rise of genomic medicine and its use of complex technology, some scholars are concerned that such inequalities of health care will not only continue but also grow. Drawing on 27 semi-structured interviews with front-line genetic workers – master’s-level genetic counselors – this qualitative study explores the factors they view as contributing to variable uptake of genetic health services among US population groups. Patient-centered factors such as attitudes, norms, and education were perceived by some genetic counselors as explanations for disparities in uptake of genetic services. However, genetic counselors more frequently discussed structural and institutional factors (e.g. cost, insurance, type and location of hospital/clinic, and/or staffing issues) when accounting for different rates of usage of genetic services among populations. The prominence of structural impediments to access found in genetic counselors’ narratives about population differences in the uptake of genetic services suggests that genetic medicine could exacerbate rather than ameliorate health disparities in the US.     

Do we facilitate the scientific process and the development of dietary guidance when findings from single studies are publicized? An American Society for Nutritional Sciences controversy session report.

This American Society for Nutritional Sciences Controversy Session presented at the 1997 Experimental Biology meeting considered whether publicity of findings from single studies facilitates or hampers the scientific process and the development of scientifically sound dietary guidance. In a 1995 survey, 78% of primary household shoppers believed it "very likely" or "somewhat likely" that in the next 5 y experts would have a completely different idea about which foods were healthy and which were not. This skepticism is fueled by the media's emphasis on reporting new and often controversial findings about food and nutrition. Media efforts are reinforced by the fact that some scientific journals regularly publicize newly published research findings. As a consequence, journalists frequently mediate scientific debate in a public forum-debate that previously was conducted among knowledgeable peers. Tight deadlines often make it difficult for reporters to thoroughly investigate findings publicized in press releases. Headlines can make results from single studies appear important, even when results are inconclusive. Finally, scientists and public policymakers have limited opportunity for making timely comments in response to an issue reported in the media. Nevertheless, the public has a right to be informed about health-related research findings to help them make decisions about their diets. The media are a valuable resource for educating the public and maintaining public interest in the importance of diet in overall health status. Nutrition scientists should be more involved in helping the media accurately convey diet and health messages.     

Evaluating and establishing national norms for mental wellbeing using the short Warwick–Edinburgh Mental Well-being Scale (SWEMWBS): findings from the Health Survey for England

Purpose

The Warwick–Edinburgh Mental Well-being Scale (WEMWBS), 14 positively worded statements, is a validated instrument to measure mental wellbeing on a population level. Less is known about the population distribution of the shorter seven-item version (SWEMWBS) or its performance as an instrument to measure wellbeing.

Methods

Using the Health Survey for England 2010–2013 (n = 27,169 adults aged 16+, nationally representative of the population), age- and sex-specific norms were estimated using means and percentiles. Criterion validity was examined using: (1) Spearman correlations (ρ) for SWEMWBS with General Health Questionnaire (GHQ-12), happiness index, EQ-VAS (2) a multinomial logit model with SWEMWBS (low, medium and high wellbeing) as the outcome and demographic, social and health behaviours as explanatory variables. Relative validity was examined by comparing SWEMWBS with WEMWBS using: (1) Spearman correlations (continuous data), and (2) the weighted kappa statistic (categorical), within population subgroups.

Results

Mean (median) SWEMWBS was 23.7 (23.2) for men and 23.2 (23.2) for women (p = 0.100). Spearman correlations were moderately sized for the happiness index (ρ = 0.53, P < 0.001), GHQ-12 (ρ = ?0.52, p < 0.001) and EQ-VAS (ρ = 0.40, p < 0.001). Participants consuming <1 portion of fruit and vegetables a day versus ≥5 (odds ratio = 1.43 95% Confidence Interval = (1.22–1.66)) and current smokers versus non-smokers (1.28 (1.15–1.41)) were more likely to have low vs medium wellbeing. Participants who binge drank versus non-drinkers were less likely to have high versus medium wellbeing (0.81 (0.71–0.92)). Spearman correlations between SWEMWBS and WEMWBS were above 0.95; weighted kappa statistics showed almost perfect agreement (0.79–0.85).

Conclusion

SWEMWBS distinguishes mental wellbeing between subgroups, similarly to WEMWBS, but is less sensitive to gender differences.