Study protocol : the empirical investigation of methods to correct for measurement error in biobanks with dietary assessment

Peer reviewedPublisher PD

We favor formal models of heuristics rather than lists of loose dichotomies: a reply to Evans and Over

In their comment on Marewski et al. (good judgments do not require complex cognition, 2009) Evans and Over (heuristic thinking and human intelligence: a commentary on Marewski, Gaissmaier and Gigerenzer, 2009) conjectured that heuristics can often lead to biases and are not error free. This is a most surprising critique. The computational models of heuristics we have tested allow for quantitative predictions of how many errors a given heuristic will make, and we and others have measured the amount of error by analysis, computer simulation, and experiment. This is clear progress over simply giving heuristics labels, such as availability, that do not allow for quantitative comparisons of errors. Evans and Over argue that the reason people rely on heuristics is the accuracy-effort trade-off. However, the comparison between heuristics and more effortful strategies, such as multiple regression, has shown that there are many situations in which a heuristic is more accurate with less effort. Finally, we do not see how the fast and frugal heuristics program could benefit from a dual-process framework unless the dual-process framework is made more precise. Instead, the dual-process framework could benefit if its two “black boxes” (Type 1 and Type 2 processes) were substituted by computational models of both heuristics and other processes

Cancer risk management strategies and perceptions of unaffected women 5 years after predictive genetic testing for BRCA1/2 mutations

In a French national cohort of unaffected females carriers/non-carriers of a BRCA1/2 mutation, long-term preventive strategies and breast/ovarian cancer risk perceptions were followed up to 5 years after test result disclosure, using self-administered questionnaires. Response rate was 74%. Carriers (N=101) were younger (average age±SD=37±10) than non-carriers (N=145; 42±12). There were four management strategies that comprised 88% of the decisions made by the unaffected carriers: 50% opted for breast surveillance alone, based on either magnetic resonance imaging (MRI) and other imaging (31%) or mammography alone (19%); 38% opted for either risk reducing salpingo-oophorectomy (RRSO) and breast surveillance, based on MRI and other imaging (28%) or mammography alone (10%). The other three strategies were: risk reducing mastectomy (RRM) and RRSO (5%), RRM alone (2%) and neither RRM/RRSO nor surveillance (6%). The results obtained for various age groups are presented here. Non-carriers often opted for screening despite their low cancer risk. Result disclosure increased carriers' short-term high breast/ovarian cancer risk perceptions (P⩽0.02) and decreased non-carriers' short- and long-term perceptions (P<0.001). During follow-up, high breast cancer risk perceptions increased with time among those who had no RRM and decreased in the opposite case; high ovarian cancer risk perceptions increased further with time among those who had no RRSO and decreased in the opposite case; RRSO did not affect breast cancer risk perceptions. Informed decision-making involves letting women know whether opting for RRSO and breast MRI surveillance is as effective in terms of survival as RRM and RRSO

Mapping an atlas of tissue-specific drosophila melanogaster metabolomes by high resolution mass spectrometry

Metabolomics can provide exciting insights into organismal function, but most work on simple models has focussed on the whole organism metabolome, so missing the contributions of individual tissues. Comprehensive metabolite profiles for ten tissues from adult Drosophila melanogaster were obtained here by two chromatographic methods, a hydrophilic interaction (HILIC) method for polar metabolites and a lipid profiling method also based on HILIC, in combination with an Orbitrap Exactive instrument. Two hundred and forty two polar metabolites were putatively identified in the various tissues, and 251 lipids were observed in positive ion mode and 61 in negative ion mode. Although many metabolites were detected in all tissues, every tissue showed characteristically abundant metabolites which could be rationalised against specific tissue functions. For example, the cuticle contained high levels of glutathione, reflecting a role in oxidative defence; the alimentary canal (like vertebrate gut) had high levels of acylcarnitines for fatty acid metabolism, and the head contained high levels of ether lipids. The male accessory gland uniquely contained decarboxylated S-adenosylmethionine. These data thus both provide valuable insights into tissue function, and a reference baseline, compatible with the FlyAtlas.org transcriptomic resource, for further metabolomic analysis of this important model organism, for example in the modelling of human inborn errors of metabolism, aging or metabolic imbalances such as diabetes

Outcome based subgroup analysis: a neglected concern

A subgroup of clinical trial subjects identified by baseline characteristics is a proper subgroup while a subgroup determined by post randomization events or measures is an improper subgroup. Both types of subgroups are often analyzed in clinical trial papers. Yet, the extensive scrutiny of subgroup analyses has almost exclusively attended to the former. The analysis of improper subgroups thereby not only flourishes in numerous disguised ways but also does so without a corresponding awareness of its pitfalls. Comparisons of the grade of angina in a heart disease trial, for example, usually include only the survivors. This paper highlights some of the distinct ways in which outcome based subgroup analysis occurs, describes the hazards associated with it, and proposes a simple alternative approach to counter its analytic bias. Data from six published trials show that outcome based subgroup analysis, like proper subgroup analysis, may be performed in a post-hoc fashion, overdone, selectively reported, and over interpreted. Six hypothetical trial scenarios illustrate the forms of hidden bias related to it. That bias can, however, be addressed by assigning clinically appropriate scores to the usually excluded subjects and performing an analysis that includes all the randomized subjects. A greater level of awareness about the practice and pitfalls of outcome based subgroup analysis is needed. When required, such an analysis should maintain the integrity of randomization. This issue needs greater practical and methodologic attention than has been accorded to it thus far

Primary care and pattern of skin diseases in a mediterranean island

BACKGROUND: In Greece where primary health care services are not fully developed, patients with simple or minor conditions have to attend to hospitals to be treated. We analysed the data of patients with cutaneous disorders attending the tertiary referral hospital on the Island of Crete, with the aim to identify the most common conditions that patients complain of, in order to define the areas where the education of General Practitioners in Dermatology must focus. METHODS: All patients attending the Dermatology ambulatory office in the Emergency Department of the University General Hospital of Heraklion from January 2003 to December 2003 were included in this retrospective analysis. The medical records of the patients (history, physical examination and laboratory investigations) were analysed to ascertain the diagnosis and the management of cases. All patients were evaluated by qualified dermatologists. RESULTS: A total of 3715 patients attended the Dermatology Clinic. Most patients were young adults in the age group 21–40 years (38.4%), and the male to female ratio was 1 to 1.2. Allergic skin diseases, mostly dermatitis and urticaria (35.7%) were the most common for attendance, followed by infectious diseases (26.1%) and insect bites (10.2%). Inflammatory and autoimmune disorders accounted for 7.9% of the cases. Pruritus of unknown origin was diagnosed in 6.3% of patients. Skin tumors were detected in 2.7%. The management of the vast majority of cases (85.0%) consisted of advice with or without a prescription, while only 4.8% of patients required admission. CONCLUSION: Allergic and infectious skin diseases were the most common cutaneous diseases in patients attending this tertiary University hospital, while the management of most patients did not require specialised care. On the basis of the present data, the training of primary health care providers in Dermatology should emphasize these common conditions, with the aim of improving primary care and alleviating the burden on hospital care

Risk perception after genetic counseling in patients with increased risk of cancer

<p>Abstract</p> <p>Background</p> <p>Counselees are more aware of genetics and seek information, reassurance, screening and genetic testing. Risk counseling is a key component of genetic counseling process helping patients to achieve a realistic view for their own personal risk and therefore adapt to the medical, psychological and familial implications of disease and to encourage the patient to make informed choices <abbrgrp><abbr bid="B1">1</abbr><abbr bid="B2">2</abbr></abbrgrp>.</p> <p>The aim of this study was to conceptualize risk perception and anxiety about cancer in individuals attending to genetic counseling.</p> <p>Methods</p> <p>The questionnaire study measured risk perception and anxiety about cancer at three time points: before and one week after initial genetic counseling and one year after completed genetic investigations. Eligibility criteria were designed to include only index patients without a previous genetic consultation in the family. A total of 215 individuals were included. Data was collected during three years period.</p> <p>Results</p> <p>Before genetic counseling all of the unaffected participants subjectively estimated their risk as higher than their objective risk. Participants with a similar risk as the population overestimated their risk most. All risk groups estimated the risk for children's/siblings to be lower than their own. The benefits of preventive surveillance program were well understood among unaffected participants.</p> <p>The difference in subjective risk perception before and directly after genetic counseling was statistically significantly lower in all risk groups. Difference in risk perception for children as well as for population was also statistically significant. Experienced anxiety about developing cancer in the unaffected subjects was lower after genetic counseling compared to baseline in all groups. Anxiety about cancer had clear correlation to perceived risk of cancer before and one year after genetic investigations.</p> <p>The affected participants overestimated their children's risk as well as risk for anyone in population. Difference in risk perception for children/siblings as for the general population was significant between the first and second measurement time points. Anxiety about developing cancer again among affected participants continued to be high throughout this investigation.</p> <p>Conclusion</p> <p>The participant's accuracy in risk perception was poor, especially in low risk individuals before genetic counseling. There was a general trend towards more accurate estimation in all risk groups after genetic counseling. The importance of preventive programs was well understood. Cancer anxiety was prevalent and associated with risk perception, but decreased after genetic counseling.</p> <p><abbrgrp><abbr bid="B1">1</abbr></abbrgrp> National Society of Genetic Counselors (2005), Genetic Counseling as a Profession. Available at <url>http://www.nsgc.org/about/definition.cfm</url> (accessed November 25th 2007)</p> <p><abbrgrp><abbr bid="B2">2</abbr></abbrgrp> Julian-Reynier C., Welkenhuysen M-, Hagoel L., Decruyenaere M., Hopwood P. (2003) Risk communication strategies: state of the art and effectiveness in the context of cancer genetic services. Eur J of Human Genetics 11, 725736.</p

Independent effect of prior exacerbation frequency and disease severity on the risk of future exacerbations of COPD: a retrospective cohort study

Few studies have researched the independent effect of COPD severity on the risk of future exacerbations adjusted by previous exacerbation frequency. We aimed to analyse the independent effect of COPD severity on the risk of exacerbations in the following year, and whether this effect was stronger or not than the effect of a previous history of exacerbations. We conducted a retrospective population-based cohort study including 900 patients with confirmed COPD. Exacerbation frequency was observed for the previous year and for the following year. Patients were defined as ‘Frequent Exacerbator’ (FE) phenotype if they suffered ?2 exacerbations in a year, and were categorised according to the severity of COPD (GOLD Grades 1–4). Odds ratios (ORs) were estimated by logistic regression adjusting for age, gender, smoking status, severity of COPD and being FE in the previous year. The main predictor of being FE among all grades of COPD severity was a history of frequent exacerbations in the previous year: adjusted OR 4.97; 95% confidence interval (CI) (3.54–6.97). COPD severity was associated with a higher risk of being FE: Crude OR GOLD Grade 4 3.86; 95% CI (1.50–9.93). However, this association diminished after adjusting for being FE in the previous year: adjusted OR 2.08; 95% CI (0.75–5.82). Our results support that a history of frequent exacerbations in the previous year is the most important independent predictor of exacerbations in the following year, also among the most severe COPD patients. Severity of COPD would be associated with a higher risk of exacerbations, but this effect would be partly determined by the exacerbations suffered in the previous year

Global and local concerns: What attitudes and beliefs motivate farmers to mitigate and adapt to climate change?

In response to agriculture\u27s vulnerability and contribution to climate change, many governments are developing initiatives that promote the adoption of mitigation and adaptation practices among farmers. Since most climate policies affecting agriculture rely on voluntary efforts by individual farmers, success requires a sound understanding of the factors that motivate farmers to change practices. Recent evidence suggests that past experience with the effects of climate change and the psychological distance associated with people\u27s concern for global and local impacts can influence environmental behavior. Here we surveyed farmers in a representative rural county in California\u27s Central Valley to examine how their intention to adopt mitigation and adaptation practices is influenced by previous climate experiences and their global and local concerns about climate change. Perceived changes in water availability had significant effects on farmers\u27 intention to adopt mitigation and adaptation strategies, which were mediated through global and local concerns respectively. This suggests that mitigation is largely motivated by psychologically distant concerns and beliefs about climate change, while adaptation is driven by psychologically proximate concerns for local impacts. This match between attitudes and behaviors according to the psychological distance at which they are cognitively construed indicates that policy and outreach initiatives may benefit by framing climate impacts and behavioral goals concordantly; either in a global context for mitigation or a local context for adaptation