How effective and cost-effective is water fluoridation for adults and adolescents? The LOTUS 10-year retrospective cohort study

OBJECTIVE

To pragmatically assess the clinical and cost-effectiveness of water fluoridation for preventing dental treatment and improving oral health in a contemporary population of adults and adolescents, using a natural experiment design.

METHODS

A 10-year retrospective cohort study (2010-2020) using routinely collected NHS dental treatment claims data. Participants were patients aged 12 years and over, attending NHS primary dental care services in England (17.8 million patients). Using recorded residential locations, individuals exposed to drinking water with an optimal fluoride concentration (≥0.7 mg F/L) were matched to non-exposed individuals using propensity scores. Number of NHS invasive dental treatments, DMFT and missing teeth were compared between groups using negative binomial regression. Total NHS dental treatment costs and cost per invasive dental treatment avoided were calculated.

RESULTS

Matching resulted in an analytical sample of 6.4 million patients. Predicted mean number of invasive NHS dental treatments (restorations 'fillings'/extractions) was 3% lower in the optimally fluoridated group (5.4) than the non-optimally fluoridated group (5.6) (IRR 0.969, 95% CI 0.967, 0.971). Predicted mean DMFT was 2% lower in the optimally fluoridated group (IRR 0.984, 95% CI 0.983, 0.985). There was no difference in the predicted mean number of missing teeth per person (IRR 1.001, 95% CI 0.999, 1.003) and no compelling evidence that water fluoridation reduced social inequalities in dental health. Optimal water fluoridation in England 2010-2020 was estimated to cost £10.30 per person (excludes initial set-up costs). NHS dental treatment costs for optimally fluoridated patients 2010-2020 were 5.5% lower, by £22.26 per person (95% CI -£21.43, -£23.09).

CONCLUSIONS

Receipt of optimal water fluoridation 2010-2020 resulted in very small positive health effects which may not be meaningful for individuals. Existing fluoridation programmes in England produced a positive return on investment between 2010 and 2020 due to slightly lower NHS dental care utilization. This return should be evaluated against the projected costs and lifespan of any proposed capital investment in water fluoridation, including new programmes.

Effect of fluoridated water on invasive NHS dental treatments for adults: the LOTUS retrospective cohort study and economic evaluation

Background

Most water fluoridation studies were conducted on children before the widespread introduction of fluoride toothpastes. There is a lack of evidence that can be applied to contemporary populations, particularly adolescents and adults.

Objective

To pragmatically assess the clinical and cost effectiveness of water fluoridation for preventing dental treatment and improving oral health in a contemporary population of adults, using a natural experiment design.

Design

Retrospective cohort study using routinely collected National Health Service dental claims (FP17) data.

Setting

National Health Service primary dental care: general dental practices, prisons, community dental services, domiciliary settings, urgent/out-of-hours and specialised referral-only services.

Participants

Dental patients aged 12 years and over living in England (n = 6,370,280).

Intervention and comparison

Individuals exposed to drinking water with a fluoride concentration ≥ 0.7 mg F/l between 2010 and 2020 were matched to non-exposed individuals on key characteristics using propensity scores.

Outcome measures

Primary: number of National Health Service invasive dental treatments (restorations/'fillings' and extractions) received per person between 2010 and 2020. Secondary: decayed, missing and filled teeth, missing teeth, inequalities, cost effectiveness and return on investment.

Data sources

National Health Service Business Services Authority dental claims data. Water quality monitoring data.

Primary outcome

Predicted mean number of invasive dental treatments was 3% lower in the optimally fluoridated group than in the sub/non-optimally fluoridated group (incidence rate ratio 0.969, 95% CI 0.967 to 0.971), a difference of -0.173 invasive dental treatments (95% CI -0.185 to -0.161). This magnitude of effect is smaller than what most stakeholders we engaged with (n = 50/54) considered meaningful.

Secondary outcomes

Mean decayed, missing and filled teeth were 2% lower in the optimally fluoridated group, with a difference of -0.212 decayed, missing and filled teeth (95% CI -0.229 to -0.194). There was no statistically significant difference in the mean number of missing teeth per person (0.006, 95% CI -0.008 to 0.021). There was no compelling evidence that water fluoridation reduced social inequalities in treatments received or missing teeth; however, decayed, missing and filled teeth data did not demonstrate a typical inequalities gradient. Optimal water fluoridation in England in 2010-20 was estimated to cost £10.30 per person (excluding original setup costs). Mean National Health Service treatment costs for fluoridated patients 2010-20 were 5.5% lower per person, by £22.26 (95% CI -£23.09 to -£21.43), and patients paid £7.64 less in National Health Service dental charges per person (2020 prices).

Limitations

Pragmatic, observational study with potential for non-differential errors of misclassification in fluoridation assignment and outcome measurement and residual and/or unmeasured confounding. Decayed, missing and filled teeth data have not been validated. Water fluoridation cost estimates are based on existing programmes between 2010 and 2020, and therefore do not include the potentially significant capital investment required for new programmes.

Conclusions

Receipt of optimal water fluoridation between 2010 and 2020 resulted in very small health effects, which may not be meaningful for individuals, and we could find no evidence of a reduction in social inequalities. Existing water fluoridation programmes in England produced a positive return on investment between 2010 and 2020 due to slightly lower National Health Service treatment costs. These relatively small savings should be evaluated against the projected costs and lifespan of any proposed capital investment in water fluoridation, including new programmes.

Future work

National Health Service dental data are a valuable resource for research. Further validation and measures to improve quality and completeness are warranted.

Trial registrations

This trial is registered as ISRCTN96479279, CAG: 20/CAG/0072, IRAS: 20/NE/0144.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme (NIHR award ref: NIHR128533) and is published in full in Public Health Research; Vol. 12, No. 5. See the NIHR Funding and Awards website for further award information.

Cascade of atopic dermatitis comorbidities in children after birth for 15 years

BACKGROUND

Individuals with atopic dermatitis often develop other conditions.

OBJECTIVE

This study aimed to determine how atopic dermatitis comorbidities develop in children over time.

METHODS

This population-based administrative cohort study used national health insurance data. We traced individuals born in Korea between 2002 and 2003 to 2018. The date of initial atopic dermatitis diagnosis was set as the index date. Fifty-three childhood comorbidities of atopic dermatitis were identified as outcomes of interest by performing a comprehensive literature search and comparing the prevalence of diagnostic codes in children with and without atopic dermatitis. Four control children per individual in the atopic dermatitis group were randomly matched based on sex and index date. The association between atopic dermatitis and the development of each specified disease was assessed using proportional hazard assumption, followed by mapping of the temporal sequences of interconnected comorbidities.

RESULTS

The atopic dermatitis and control groups contained 67,632 and 270,528 individuals, respectively. The median age at the index date was 10 months, whereas the median follow-up period was 15 years. Twenty diseases that were associated with a higher risk of atopic dermatitis were identified and a chain of interconnected conditions created. The progression began in childhood with febrile seizures, constipation, and asthma, and was later associated with the emergence of food allergy, allergic rhinitis, psychiatric disorders, and autoimmune diseases.

CONCLUSION

Our study highlights the temporal nature of atopic dermatitis comorbidities in children, and indicates that an understanding of the comorbidities may inform its clinical management and treatment.

Associations between prenatal exposure to per- and polyfluoroalkyl substances and wheezing and asthma symptoms in 4-year-old children: The Japan Environment and Children's Study

The effects of early-life exposure to per- and polyfluoroalkyl substances (PFAS) on the onset of asthma in children have been unclear. We examined the association between prenatal PFAS exposure and wheezing and asthma symptoms among 4-year-old children in a total of 17,856 mother-child pairs from the Japan Environment and Children's Study. Maternal first-trimester serum concentrations of six PFAS were used for the exposure assessment. We defined "wheeze ever," "current wheeze," "current symptoms of severe asthma," and "asthma ever" at the age of 4 years by the responses to the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire, and "doctor-diagnosed asthma" by the response to a corresponding question. Multivariate logistic regression models were used to examine exposure-outcome associations. Our findings revealed that doubling of the PFOA concentration was associated with a reduced occurrence of "wheeze ever," yielding an adjusted odds ratio of 0.94 (95% CI: 0.90-0.98). Also, doubling in the concentrations of PFOA and PFHxS was associated with a decreased prevalence of "asthma ever," with adjusted odds ratios of 0.94 (95% CI: 0.88-1.00) and 0.95 (95% CI: 0.90-0.99), respectively. However, these associations were not significant after applying the Bonferroni correction. The estimated exposure-response curves were nearly linear with a subtle or flat slope. When stratified by the child's sex or the mother's history of asthma, most of the estimated confidence intervals were overlapped between each pair of strata. Regional stratification analysis indicated low-to-moderate heterogeneity in 12 exposure-outcome pairs and moderate-to-high heterogeneity in 9 out of the 30 examined pairs. This study found no clear associations between prenatal PFAS exposure and the prevalence of wheezing and asthma among children at the age of 4 years.

Adverse COVID-19 outcomes in American Veterans with age-related macular degeneration: a case-control study

OBJECTIVES

Prior studies suggest that patients with age-related macular degeneration (AMD) have poorer COVID-19 outcomes. This study aims to evaluate whether AMD is associated with adverse COVID-19 outcomes in a large clinical database.

DESIGN

Case-control study.

SETTING

We obtained demographic and clinical data from a national US Veterans Affairs (VA) database for all Veterans aged 50 years or older with positive COVID-19 testing prior to 2 May 2021.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure was hospitalisation. Secondary outcome measures were intensive care unit admission, mechanical ventilation and death. Potential associations between AMD and outcome measures occurring within 60 days of COVID-19 diagnosis were evaluated using multiple logistic regression analyses.

RESULTS

Of the 171 325 patients in the study cohort, 7913 (5%) had AMD and 2152 (1%) had severe AMD, defined as advanced atrophic or exudative AMD disease coding. Multiple logistic regression adjusting for age, Charlson Comorbidity Index, sex, race, ethnicity and COVID-19 timing showed that an AMD diagnosis did not significantly increase the odds of hospitalisation (p=0.11). Using a Bonferroni-adjusted significance level of 0.006, AMD and severe AMD also were not significant predictors for the secondary outcomes, except for AMD being modestly protective for death (p=0.002).

CONCLUSIONS

After adjusting for other variables, neither AMD nor severe AMD was a risk factor for adverse COVID-19 outcomes in the VA healthcare system. These findings indicate that an AMD diagnosis alone should not alter recommended ophthalmic management based on COVID-19 adverse outcome risk.

Sex Differences in Temporal Trends and Risk Factors of Aortic Dissection in Taiwan

Background Although sex differences in the epidemiological features of aortic dissection (AD) are known, whether there were sex differences in the associations of comorbidities and risk factors with AD is unclear. We evaluated the temporal trends and risk factors of AD by sex. Methods and Results Using claims data from a universal health insurance program linked to the National Death Registry in Taiwan, we identified 16 368 men and 7052 women with newly diagnosed AD from 2005 to 2018. In the case-control analysis, a matched control group without AD was selected for men and women separately. Conditional logistic regression was used to evaluate risk factors of AD and sex differences. Over the 14 years, the annual incidence of diagnosed AD was 12.69 and 5.34 per 100 000 in men and women, respectively. The 30-day mortality was greater in women than in men (18.1% versus 14.1%; adjusted odds ratio [95% CI], 1.19 [1.10-1.29]), and the sex difference was observed mainly in patients not treated with surgery. The 30-day mortality declined over time in male patients undergoing surgical treatments, but no significantly temporal change was found in other patient groups stratified by sex and surgery. After multivariable adjustments, atrial fibrillation, chronic kidney disease, and coronary artery bypass graft surgery were associated with a greater increase in the odds of AD occurrence in women than in men. Conclusions Greater 30-day mortality and stronger associations of atrial fibrillation, chronic kidney disease, and coronary artery bypass graft surgery with AD in women than in men require further attention.

The effects of multi-nutrient formulas containing a combination of n-3 PUFA and B vitamins on cognition in the older adult: a systematic review and meta-analysis

There is now evidence to suggest that there may be an interaction between B vitamins and n-3 PUFA, with suggestions that increasing intake of both nutrients simultaneously may benefit cognition in older adults. The aim of this systematic review was to investigate whether supplementation with a combination of n-3 PUFA and B vitamins can prevent cognitive decline in older adults. Randomised controlled trials conducted in older adults that measured cognitive function were retrieved. The included trials provided a combination of n-3 PUFA and B vitamins alone, or in combination with other nutrients. Trials that provided n-3 PUFA alone and also measured B vitamin status or provided B vitamin supplementation alone and measured n-3 PUFA status were also included. The databases searched were The Cochrane Library, EMBASE, CINAHL, Scopus and MEDLINE. A total of 14 papers were included in the analysis (n 4913; age: 60-70 years; follow-up 24 weeks to 4 years). The meta-analysis results found a significant benefit of nutrient formulas, which included both n-3 PUFA and B vitamins alongside other nutrients, v. placebo on global cognition assessed using composite scores from a neuropsychological test battery (G = 0·23, P = 0·002), global cognition using single measures of cognition (G = 0·28, P = 0·004) and episodic memory (G = 0·32, P = 0·001). The results indicate that providing a combination of n-3 PUFA and B vitamins as part of a multi-nutrient formula benefits cognition in older adults v. a placebo, and the potential for an interaction between these key nutrients should be considered in future experimental work.

Overweight, obesity, and individual symptoms of depression: A multicohort study with replication in UK Biobank

OBJECTIVES

Obesity is associated with increased risk of depression, but the extent to which this association is symptom-specific is unknown. We examined the associations of overweight and obesity with individual depressive symptoms.

METHODS

We pooled data from 15 population-based cohorts comprising 57,532 individuals aged 18 to 100 years at study entry. Primary analyses were replicated in an independent cohort, the UK Biobank study (n = 122,341, age range 38 to 72). Height and weight were assessed at baseline and body mass index (BMI) was computed. Using validated self-report measures, 24 depressive symptoms were ascertained once in 16 cross-sectional, and twice in 7 prospective cohort studies (mean follow-up 3.2 years).

RESULTS

In the pooled analysis of the primary cohorts, 22,045 (38.3 %) participants were overweight (BMI between 25 and 29.9 kg/m2), 12,025 (20.9 %) class I obese (BMI between 30 and 34.9 kg/m2), 7,467 (13.0 %) class II-III obese (BMI ≥ 35 kg/m2); and 7,046 (12.3 %) were classified as depressed. After multivariable adjustment, obesity class I was cross-sectionally associated with 1.11-fold (95 % confidence interval 1.01-1.22), and obesity class II-III with 1.31-fold (1.16-1.49) higher odds of overall depression. In symptom-specific analyses, robust associations were apparent for 4 of the 24 depressive symptoms ('could not get going/lack of energy', 'little interest in doing things', 'feeling bad about yourself, and 'feeling depressed'), with confounder-adjusted odds ratios of having 3 or 4 of these symptoms being 1.32 (1.10-1.57) for individuals with obesity class I, and 1.70 (1.34-2.14) for those with obesity class II-III. Elevated C-reactive protein and 21 obesity-related diseases explained 23 %-31 % of these associations. Symptom-specific associations were confirmed in longitudinal analyses where obesity preceded symptom onset, were stronger in women compared with men, and were replicated in UK Biobank.

CONCLUSIONS

Obesity is associated with a distinct set of depressive symptoms. These associations are partially explained by systemic inflammation and obesity-related morbidity. Awareness of this obesity-related symptom profile and its underlying biological correlates may inform better targeted treatments for comorbid obesity and depression.

Reporting only relative effect measures was potentially misleading: some good practices for improving the soundness of epidemiological results

OBJECTIVE

In the medical and epidemiological literature there is a growing tendency to report an excessive number of decimal digits (often three, sometimes four), especially when measures of relative occurrence are small; this can be misleading.

STUDY DESIGN AND SETTING

We combined mathematical and statistical reasoning about the precision of relative risks with the meaning of the decimal part of the same measures from biological and public health perspectives.

RESULTS

We identified a general rule for minimizing the mathematical error due to rounding of relative risks, depending on the background absolute rate, which justifies the use of one or more decimal digits for estimates close to 1.

CONCLUSIONS

We suggest that both relative and absolute risk measures (expressed as a rates) should be reported, and two decimal digits should be used for relative risk close to 1 only if the background rate is at least 1/1,000 py. The use of more than two decimal digits is justified only when the background rate is high (ie, 1/10 py).

Cardiovascular risk factors and mortality in hospitalized patients with COVID-19: systematic review and meta-analysis of 45 studies and 18,300 patients

BACKGROUND

A high prevalence of cardiovascular risk factors including age, male sex, hypertension, diabetes, and tobacco use, has been reported in patients with Coronavirus disease 2019 (COVID-19) who experienced adverse outcome. The aim of this study was to investigate the relationship between cardiovascular risk factors and in-hospital mortality in patients with COVID-19.

METHODS

MEDLINE, Cochrane, Web of Sciences, and SCOPUS were searched for retrospective or prospective observational studies reporting data on cardiovascular risk factors and in-hospital mortality in patients with COVID-19. Univariable and multivariable age-adjusted analyses were conducted to evaluate the association between cardiovascular risk factors and the occurrence of in-hospital death.

RESULTS

The analysis included 45 studies enrolling 18,300 patients. The pooled estimate of in-hospital mortality was 12% (95% CI 9-15%). The univariable meta-regression analysis showed a significant association between age (coefficient: 1.06; 95% CI 1.04-1.09; p < 0.001), diabetes (coefficient: 1.04; 95% CI 1.02-1.07; p < 0.001) and hypertension (coefficient: 1.01; 95% CI 1.01-1.03; p = 0.013) with in-hospital death. Male sex and smoking did not significantly affect mortality. At multivariable age-adjusted meta-regression analysis, diabetes was significantly associated with in-hospital mortality (coefficient: 1.02; 95% CI 1.01-1.05; p = 0.043); conversely, hypertension was no longer significant after adjustment for age (coefficient: 1.00; 95% CI 0.99-1.01; p = 0.820). A significant association between age and in-hospital mortality was confirmed in all multivariable models.

CONCLUSIONS

This meta-analysis suggests that older age and diabetes are associated with higher risk of in-hospital mortality in patients infected by SARS-CoV-2. Conversely, male sex, hypertension, and smoking did not independently correlate with fatal outcome.

Factors associated with low birth weight at term: a population-based linkage study of the 100 million Brazilian cohort

BACKGROUND

Factors associated with low birth weight at term (TLBW), a proxy for intrauterine growth restriction (IUGR), are not well-elucidated in socioeconomically vulnerable populations. This study aimed to identify the factors associated with TLBW in impoverished Brazilian women.

METHODS

Records in the 100 Million Brazilian Cohort database were linked to those in the National System of Information on Live Births (SINASC) to obtain obstetric, maternal, birth and socioeconomic data between 2001 and 2015. Multivariate logistic regression was performed to investigate associations between variables of exposure and TLBW.

RESULTS

Of 8,768,930 term live births analyzed, 3.7% presented TLBW. The highest odds of TLBW were associated with female newborns (OR: 1.49; 95% CI: 1.47-1.50), whose mothers were black (OR: 1.20; 95% CI: 1.18-1.22), had a low educational level (OR: 1.57; 95% CI: 1.53-1.62), were aged ≥35 years (OR: 1.44; 95% CI: 1.43-1.46), had a low number of prenatal care visits (OR: 2.48; 95% CI: 2.42-2.54) and were primiparous (OR: 1.62; 95% CI: 1.60-1.64). Lower odds of TLBW were found among infants whose mothers lived in the North, Northeast and Center-West regions of Brazil compared to those in the South.

CONCLUSION

Multiple aspects were associated with TLBW, highlighting the need to comprehensively examine the mechanisms underlying these factors, especially in more vulnerable Brazilian populations, in order to contribute to the elaboration of health policies and promote better conditions of life for poor and extremely poor mothers and children.

Association between socioeconomic status and the development of mental and physical health conditions in adulthood: a multi-cohort study

BACKGROUND

Socioeconomic disadvantage is a risk factor for many diseases. We characterised cascades of these conditions by using a data-driven approach to examine the association between socioeconomic status and temporal sequences in the development of 56 common diseases and health conditions.

METHODS

In this multi-cohort study, we used data from two Finnish prospective cohort studies: the Health and Social Support study and the Finnish Public Sector study. Our pooled prospective primary analysis data comprised 109 246 Finnish adults aged 17-77 years at study entry. We captured socioeconomic status using area deprivation and education at baseline (1998-2013). Participants were followed up for health conditions diagnosed according to the WHO International Classification of Diseases until 2016 using linkage to national health records. We tested the generalisability of our findings with an independent UK cohort study-the Whitehall II study (9838 people, baseline in 1997, follow-up to 2017)-using a further socioeconomic status indicator, occupational position.

FINDINGS

During 1 110 831 person-years at risk, we recorded 245 573 hospitalisations in the Finnish cohorts; the corresponding numbers in the UK study were 60 946 hospitalisations in 186 572 person-years. Across the three socioeconomic position indicators and after adjustment for lifestyle factors, compared with more advantaged groups, low socioeconomic status was associated with increased risk for 18 (32·1%) of the 56 conditions. 16 diseases formed a cascade of inter-related health conditions with a hazard ratio greater than 5. This sequence began with psychiatric disorders, substance abuse, and self-harm, which were associated with later liver and renal diseases, ischaemic heart disease, cerebral infarction, chronic obstructive bronchitis, lung cancer, and dementia.

INTERPRETATION

Our findings highlight the importance of mental health and behavioural problems in setting in motion the development of a range of socioeconomically patterned physical illnesses. Policy and health-care practice addressing psychological health issues in social context and early in the life course could be effective strategies for reducing health inequalities.

FUNDING

UK Medical Research Council, US National Institute on Aging, NordForsk, British Heart Foundation, Academy of Finland, and Helsinki Institute of Life Science.

Online randomized controlled experiments at scale: lessons and extensions to medicine

Background

Many technology companies, including Airbnb, Amazon, Booking.com, eBay, Facebook, Google, LinkedIn, Lyft, Microsoft, Netflix, Twitter, Uber, and Yahoo!/Oath, run online randomized controlled experiments at scale, namely hundreds of concurrent controlled experiments on millions of users each, commonly referred to as A/B tests. Originally derived from the same statistical roots, randomized controlled trials (RCTs) in medicine are now criticized for being expensive and difficult, while in technology, the marginal cost of such experiments is approaching zero and the value for data-driven decision-making is broadly recognized.

Methods and results

This is an overview of key scaling lessons learned in the technology field. They include (1) a focus on metrics, an overall evaluation criterion and thousands of metrics for insights and debugging, automatically computed for every experiment; (2) quick release cycles with automated ramp-up and shut-down that afford agile and safe experimentation, leading to consistent incremental progress over time; and (3) a culture of ‘test everything’ because most ideas fail and tiny changes sometimes show surprising outcomes worth millions of dollars annually.

Technological advances, online interactions, and the availability of large-scale data allowed technology companies to take the science of RCTs and use them as online randomized controlled experiments at large scale with hundreds of such concurrent experiments running on any given day on a wide range of software products, be they web sites, mobile applications, or desktop applications. Rather than hindering innovation, these experiments enabled accelerated innovation with clear improvements to key metrics, including user experience and revenue. As healthcare increases interactions with patients utilizing these modern channels of web sites and digital health applications, many of the lessons apply. The most innovative technological field has recognized that systematic series of randomized trials with numerous failures of the most promising ideas leads to sustainable improvement.

Conclusion

While there are many differences between technology and medicine, it is worth considering whether and how similar designs can be applied via simple RCTs that focus on healthcare decision-making or service delivery. Changes – small and large – should undergo continuous and repeated evaluations in randomized trials and learning from their results will enable accelerated healthcare improvements.

Evidence Collection and Evaluation for the Development of Dietary Guidelines and Public Policy on Nutrition

Dietary guidelines and recommendations, usually developed by government bodies or large authoritative organizations, have major downstream effects on public policy. A growing body of evidence supports the notion that there are serious deficiencies in the methods used to develop dietary guidelines. Such deficiencies include the failure to access or conduct comprehensive systematic reviews, a lack of systematic or rigorous evaluation of the quality of the evidence, a failure to acknowledge the limitations of the evidence base underlying recommendations, and insufficiently stringent management of conflicts of interest. These issues may be addressed by adhering to international standards for guideline development, including adopting systematic review methodology and using rigorous systems to evaluate the certainty of the evidence and to move from evidence to recommendations, of which the GRADE approach (Grading of Recommendations Assessment,Development and Evaluation) is the most rigorous and fully developed. Improving the methods by which dietary guidelines are produced has considerable potential to substantially improve public policy decision-making.

Limitations and Misinterpretations of E-Values for Sensitivity Analyses of Observational Studies

The E-value was recently introduced on the basis of earlier work as "the minimum strength of association…that an unmeasured confounder would need to have with both the treatment and the outcome to fully explain away a specific treatment-outcome association, conditional on the measured covariates." E-values have been proposed for wide application in observational studies evaluating causality. However, they have limitations and are prone to misinterpretation. E-values have a monotonic, almost linear relationship with effect estimates and thus offer no additional information beyond what effect estimates can convey. Whereas effect estimates are based on real data, E-values may make unrealistic assumptions. No general rule can exist about what is a "small enough" E-value, and users of the biomedical literature are not familiar with how to interpret a range of E-values. Problems arise for any measure dependent on effect estimates and their CIs-for example, bias due to selective reporting and dependence on choice of exposure contrast and level of confidence. The automation of E-values may give an excuse not to think seriously about confounding. Moreover, biases other than confounding may still undermine results. Instead of misused or misinterpreted E-values, the authors recommend judicious use of existing methods for sensitivity analyses with careful assumptions; systematic assessments of whether and how known confounders have been handled, along with consideration of their prevalence and magnitude; thorough discussion of the potential for unknown confounders considering the study design and field of application; and explicit caution in making causal claims from observational studies.

The intriguing evolution of effect sizes in biomedical research over time: smaller but more often statistically significant

Background

In medicine, effect sizes (ESs) allow the effects of independent variables (including risk/protective factors or treatment interventions) on dependent variables (e.g., health outcomes) to be quantified. Given that many public health decisions and health care policies are based on ES estimates, it is important to assess how ESs are used in the biomedical literature and to investigate potential trends in their reporting over time.

Results

Through a big data approach, the text mining process automatically extracted 814 120 ESs from 13 322 754 PubMed abstracts. Eligible ESs were risk ratio, odds ratio, and hazard ratio, along with their confidence intervals. Here we show a remarkable decrease of ES values in PubMed abstracts between 1990 and 2015 while, concomitantly, results become more often statistically significant. Medians of ES values have decreased over time for both “risk” and “protective” values. This trend was found in nearly all fields of biomedical research, with the most marked downward tendency in genetics. Over the same period, the proportion of statistically significant ESs increased regularly: among the abstracts with at least 1 ES, 74% were statistically significant in 1990–1995, vs 85% in 2010–2015.

Conclusions

whereas decreasing ESs could be an intrinsic evolution in biomedical research, the concomitant increase of statistically significant results is more intriguing. Although it is likely that growing sample sizes in biomedical research could explain these results, another explanation may lie in the “publish or perish” context of scientific research, with the probability of a growing orientation toward sensationalism in research reports. Important provisions must be made to improve the credibility of biomedical research and limit waste of resources.

The Failure to Measure Dietary Intake Engendered a Fictional Discourse on Diet-Disease Relations

Controversies regarding the putative health effects of dietary sugar, salt, fat, and cholesterol are not driven by legitimate differences in scientific inference from valid evidence, but by a fictional discourse on diet-disease relations driven by decades of deeply flawed and demonstrably misleading epidemiologic research. Over the past 60 years, epidemiologists published tens of thousands of reports asserting that dietary intake was a major contributing factor to chronic non-communicable diseases despite the fact that epidemiologic methods do not measure dietary intake. In lieu of measuring actual dietary intake, epidemiologists collected millions of unverified verbal and textual reports of memories of perceptions of dietary intake. Given that actual dietary intake and reported memories of perceptions of intake are not in the same ontological category, epidemiologists committed the logical fallacy of "Misplaced Concreteness." This error was exacerbated when the anecdotal (self-reported) data were impermissibly transformed (i.e., pseudo-quantified) into proxy-estimates of nutrient and caloric consumption via the assignment of "reference" values from databases of questionable validity and comprehensiveness. These errors were further compounded when statistical analyses of diet-disease relations were performed using the pseudo-quantified anecdotal data. These fatal measurement, analytic, and inferential flaws were obscured when epidemiologists failed to cite decades of research demonstrating that the proxy-estimates they created were often physiologically implausible (i.e., meaningless) and had no verifiable quantitative relation to the actual nutrient or caloric consumption of participants. In this critical analysis, we present substantial evidence to support our contention that current controversies and public confusion regarding diet-disease relations were generated by tens of thousands of deeply flawed, demonstrably misleading, and pseudoscientific epidemiologic reports. We challenge the field of nutrition to regain lost credibility by acknowledging the empirical and theoretical refutations of their memory-based methods and ensure that rigorous (objective) scientific methods are used to study the role of diet in chronic disease.

Overdiagnosis and overtreatment in rheumatology: a little caution is in order

Overdiagnosis is a term coined by experts in cancer screening to point to indolent cancers detected by screening that would have never led to manifest health problems. Overdiagnosis leads to unnecessary medical care (overtreatment), anxiety and cost. In rheumatology overdiagnosis and overtreatment are hardly discussed but likely present. This viewpoint examines how our prevailing views on the management of inflammatory rheumatic diseases may relate to overdiagnosis and overtreatment. Six paradigms of modern rheumatology will be discussed: early diagnosis, intensive treatment, remission, prognosis and risk stratification, evidence-based rheumatology, and precision medicine. It is concluded that, in spite of the enormous progress that they have brought, all paradigms bear the intrinsic dangers of overdiagnosis and overtreatment. So a little caution is in order.

Perspective: Limiting Dependence on Nonrandomized Studies and Improving Randomized Trials in Human Nutrition Research: Why and How

A large majority of human nutrition research uses nonrandomized observational designs, but this has led to little reliable progress. This is mostly due to many epistemologic problems, the most important of which are as follows: difficulty detecting small (or even tiny) effect sizes reliably for nutritional risk factors and nutrition-related interventions; difficulty properly accounting for massive confounding among many nutrients, clinical outcomes, and other variables; difficulty measuring diet accurately; and suboptimal research reporting. Tiny effect sizes and massive confounding are largely unfixable problems that narrowly confine the scenarios in which nonrandomized observational research is useful. Although nonrandomized studies and randomized trials have different priorities (assessment of long-term causality compared with assessment of treatment effects), the odds for obtaining reliable information with the former are limited. Randomized study designs should therefore largely replace nonrandomized studies in human nutrition research going forward. To achieve this, many of the limitations that have traditionally plagued most randomized trials in nutrition, such as small sample size, short length of follow-up, high cost, and selective reporting, among others, must be overcome. Pivotal megatrials with tens of thousands of participants and lifelong follow-up are possible in nutrition science with proper streamlining of operational costs. Fixable problems that have undermined observational research, such as dietary measurement error and selective reporting, need to be addressed in randomized trials. For focused questions in which dietary adherence is important to maximize, trials with direct observation of participants in experimental in-house settings may offer clean answers on short-term metabolic outcomes. Other study designs of randomized trials to consider in nutrition include registry-based designs and "N-of-1" designs. Mendelian randomization designs may also offer some more reliable leads for testing interventions in trials. Collectively, an improved randomized agenda may clarify many things in nutrition science that might never be answered credibly with nonrandomized observational designs.

Reporting bias in the literature on the associations of health-related behaviors and statins with cardiovascular disease and all-cause mortality

Reporting bias in the literature occurs when there is selective revealing or suppression of results, influenced by the direction of findings. We assessed the risk of reporting bias in the epidemiological literature on health-related behavior (tobacco, alcohol, diet, physical activity, and sedentary behavior) and cardiovascular disease mortality and all-cause mortality and provided a comparative assessment of reporting bias between health-related behavior and statin (in primary prevention) meta-analyses. We searched Medline, Embase, Cochrane Methodology Register Database, and Web of Science for systematic reviews synthesizing the associations of health-related behavior and statins with cardiovascular disease mortality and all-cause mortality published between 2010 and 2016. Risk of bias in systematic reviews was assessed using the ROBIS tool. Reporting bias in the literature was evaluated via small-study effect and excess significance tests. We included 49 systematic reviews in our study. The majority of these reviews exhibited a high overall risk of bias, with a higher extent in health-related behavior reviews, relative to statins. We reperformed 111 meta-analyses conducted across these reviews, of which 65% had statistically significant results (P < 0.05). Around 22% of health-related behavior meta-analyses showed small-study effect, as compared to none of statin meta-analyses. Physical activity and the smoking research areas had more than 40% of meta-analyses with small-study effect. We found evidence of excess significance in 26% of health-related behavior meta-analyses, as compared to none of statin meta-analyses. Half of the meta-analyses from physical activity, 26% from diet, 18% from sedentary behavior, 14% for smoking, and 12% from alcohol showed evidence of excess significance bias. These biases may be distorting the body of evidence available by providing inaccurate estimates of preventive effects on cardiovascular and all-cause mortality.

When addiction symptoms and life problems diverge: a latent class analysis of problematic gaming in a representative multinational sample of European adolescents

The proposed diagnosis of Internet gaming disorder (IGD) in DSM-5 has been criticized for "borrowing" criteria related to substance addiction, as this might result in misclassifying highly involved gamers as having a disorder. In this paper, we took a person-centered statistical approach to group adolescent gamers by levels of addiction-related symptoms and gaming-related problems, compared these groups to traditional scale scores for IGD, and checked how groups were related to psychosocial well-being using a preregistered analysis plan. We performed latent class analysis and regression with items from IGD and psychosocial well-being scales in a representative sample of 7865 adolescent European gamers. Symptoms and problems matched in only two groups: an IGD class (2.2%) having a high level of symptoms and problems and a Normative class (63.5%) having low levels of symptoms and problems. We also identified two classes comprising 30.9% of our sample that would be misclassified based on their report of gaming-related problems: an Engaged class (7.3%) that seemed to correspond to the engaged gamers described in previous literature, and a Concerned class (23.6%) reporting few symptoms but moderate to high levels of problems. Our findings suggest that a reformulation of IGD is needed. Treating Engaged gamers as having IGD when their poor well-being might not be gaming related may delay appropriate treatment, while Concerned gamers may need help to reduce gaming but would not be identified as such. Additional work to describe the phenomenology of these two groups would help refine diagnosis, prevention and treatment for IGD.

Misrepresentation and distortion of research in biomedical literature

Publication in peer-reviewed journals is an essential step in the scientific process. However, publication is not simply the reporting of facts arising from a straightforward analysis thereof. Authors have broad latitude when writing their reports and may be tempted to consciously or unconsciously "spin" their study findings. Spin has been defined as a specific intentional or unintentional reporting that fails to faithfully reflect the nature and range of findings and that could affect the impression the results produce in readers. This article, based on a literature review, reports the various practices of spin from misreporting by "beautification" of methods to misreporting by misinterpreting the results. It provides data on the prevalence of some forms of spin in specific fields and the possible effects of some types of spin on readers' interpretation and research dissemination. We also discuss why researchers would spin their reports and possible ways to avoid it.

Welfare-to-work interventions and their effects on the mental and physical health of lone parents and their children

BACKGROUND

Lone parents in high-income countries have high rates of poverty (including in-work poverty) and poor health. Employment requirements for these parents are increasingly common. 'Welfare-to-work' (WtW) interventions involving financial sanctions and incentives, training, childcare subsidies and lifetime limits on benefit receipt have been used to support or mandate employment among lone parents. These and other interventions that affect employment and income may also affect people's health, and it is important to understand the available evidence on these effects in lone parents.

OBJECTIVES

To assess the effects of WtW interventions on mental and physical health in lone parents and their children living in high-income countries. The secondary objective is to assess the effects of welfare-to-work interventions on employment and income.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE Ovid, Embase Ovid, PsycINFO EBSCO, ERIC EBSCO, SocINDEX EBSCO, CINAHL EBSCO, Econlit EBSCO, Web of Science ISI, Applied Social Sciences Index and Abstracts (ASSIA) via Proquest, International Bibliography of the Social Sciences (IBSS) via ProQuest, Social Services Abstracts via Proquest, Sociological Abstracts via Proquest, Campbell Library, NHS Economic Evaluation Database (NHS EED) (CRD York), Turning Research into Practice (TRIP), OpenGrey and Planex. We also searched bibliographies of included publications and relevant reviews, in addition to many relevant websites. We identified many included publications by handsearching. We performed the searches in 2011, 2013 and April 2016.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of mandatory or voluntary WtW interventions for lone parents in high-income countries, reporting impacts on parental mental health, parental physical health, child mental health or child physical health.

DATA COLLECTION AND ANALYSIS

One review author extracted data using a standardised extraction form, and another checked them. Two authors independently assessed risk of bias and the quality of the evidence. We contacted study authors to obtain measures of variance and conducted meta-analyses where possible. We synthesised data at three time points: 18 to 24 months (T1), 25 to 48 months (T2) and 49 to 72 months (T3).

MAIN RESULTS

Twelve studies involving 27,482 participants met the inclusion criteria. Interventions were either mandatory or voluntary and included up to 10 discrete components in varying combinations. All but one study took place in North America. Although we searched for parental health outcomes, the vast majority of the sample in all included studies were female. Therefore, we describe adult health outcomes as 'maternal' throughout the results section. We downgraded the quality of all evidence at least one level because outcome assessors were not blinded. Follow-up ranged from 18 months to six years. The effects of welfare-to-work interventions on health were generally positive but of a magnitude unlikely to have any tangible effects.At T1 there was moderate-quality evidence of a very small negative impact on maternal mental health (standardised mean difference (SMD) 0.07, 95% Confidence Interval (CI) 0.00 to 0.14; N = 3352; studies = 2)); at T2, moderate-quality evidence of no effect (SMD 0.00, 95% CI 0.05 to 0.05; N = 7091; studies = 3); and at T3, low-quality evidence of a very small positive effect (SMD -0.07, 95% CI -0.15 to 0.00; N = 8873; studies = 4). There was evidence of very small positive effects on maternal physical health at T1 (risk ratio (RR) 0.85, 95% CI 0.54 to 1.36; N = 311; 1 study, low quality) and T2 (RR 1.06, 95% CI 0.95 to 1.18; N = 2551; 2 studies, moderate quality), and of a very small negative effect at T3 (RR 0.97, 95% CI 0.91 to 1.04; N = 1854; 1 study, low quality).At T1, there was moderate-quality evidence of a very small negative impact on child mental health (SMD 0.01, 95% CI -0.06 to 0.09; N = 2762; studies = 1); at T2, of a very small positive effect (SMD -0.04, 95% CI -0.08 to 0.01; N = 7560; studies = 5), and at T3, there was low-quality evidence of a very small positive effect (SMD -0.05, 95% CI -0.16 to 0.05; N = 3643; studies = 3). Moderate-quality evidence for effects on child physical health showed a very small negative effect at T1 (SMD -0.05, 95% CI -0.12 to 0.03; N = 2762; studies = 1), a very small positive effect at T2 (SMD 0.07, 95% CI 0.01 to 0.12; N = 7195; studies = 3), and a very small positive effect at T3 (SMD 0.01, 95% CI -0.04 to 0.06; N = 8083; studies = 5). There was some evidence of larger negative effects on health, but this was of low or very low quality.There were small positive effects on employment and income at 18 to 48 months (moderate-quality evidence), but these were largely absent at 49 to 72 months (very low to moderate-quality evidence), often due to control group members moving into work independently. Since the majority of the studies were conducted in North America before the year 2000, generalisabilty may be limited. However, all study sites were similar in that they were high-income countries with developed social welfare systems.

AUTHORS' CONCLUSIONS

The effects of WtW on health are largely of a magnitude that is unlikely to have tangible impacts. Since income and employment are hypothesised to mediate effects on health, it is possible that these negligible health impacts result from the small effects on economic outcomes. Even where employment and income were higher for the lone parents in WtW, poverty was still high for the majority of the lone parents in many of the studies. Perhaps because of this, depression also remained very high for lone parents whether they were in WtW or not. There is a lack of robust evidence on the health effects of WtW for lone parents outside North America.

An Evaluation of Army Wellness Center Clients' Health-Related Outcomes

PURPOSE

To examine whether Army community members participating in a best-practice based workplace health promotion program (WHPP) experience goal-moderated improvements in health-related outcomes.

DESIGN

Pretest/posttest outcome evaluation examining an autonomously participating client cohort over 1 year.

SETTING

Army Wellness Center facilities on 19 Army installations.

PARTICIPANTS

Army community members sample (N = 5703), mostly Active Duty Soldiers (64%).

INTERVENTION

Assessment of health risks with feedback, health assessments, health education classes, and health coaching sessions conducted by health educators at a recommended frequency of once a month for 3 to 12 months.

MEASURES

Initial and follow-up outcome assessments of body mass index (BMI), body fat, cardiorespiratory fitness, blood pressure, and perceived stress.

ANALYSIS

Mixed model linear regression testing for goal-moderated improvements in outcomes.

RESULTS

Clients experienced significant improvements in body fat (-2% change), perceived stress (-6% to -12% change), cardiorespiratory fitness (+6% change), and blood pressure (-1% change) regardless of health-related goal. Only clients with a weight loss goal experienced BMI improvement (-1% change). Follow-up outcome assessment rates ranged from 44% (N = 2509) for BMI to 6% (N = 342) for perceived stress.

CONCLUSION

Army Wellness Center clients with at least 1 follow-up outcome assessment experienced improvements in military readiness correlates and chronic disease risk factors. Evaluation design and follow-up-related limitations notwithstanding results suggest that best practices in WHPPs can effectively serve a globally distributed military force.

Welfare-to-work interventions and their effects on the mental and physical health of lone parents and their children

BACKGROUND

Lone parents in high-income countries have high rates of poverty (including in-work poverty) and poor health. Employment requirements for these parents are increasingly common. 'Welfare-to-work' (WtW) interventions involving financial sanctions and incentives, training, childcare subsidies and lifetime limits on benefit receipt have been used to support or mandate employment among lone parents. These and other interventions that affect employment and income may also affect people's health, and it is important to understand the available evidence on these effects in lone parents.

OBJECTIVES

To assess the effects of WtW interventions on mental and physical health in lone parents and their children living in high-income countries. The secondary objective is to assess the effects of welfare-to-work interventions on employment and income.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE Ovid, Embase Ovid, PsycINFO EBSCO, ERIC EBSCO, SocINDEX EBSCO, CINAHL EBSCO, Econlit EBSCO, Web of Science ISI, Applied Social Sciences Index and Abstracts (ASSIA) via Proquest, International Bibliography of the Social Sciences (IBSS) via ProQuest, Social Services Abstracts via Proquest, Sociological Abstracts via Proquest, Campbell Library, NHS Economic Evaluation Database (NHS EED) (CRD York), Turning Research into Practice (TRIP), OpenGrey and Planex. We also searched bibliographies of included publications and relevant reviews, in addition to many relevant websites. We identified many included publications by handsearching. We performed the searches in 2011, 2013 and April 2016.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of mandatory or voluntary WtW interventions for lone parents in high-income countries, reporting impacts on parental mental health, parental physical health, child mental health or child physical health.

DATA COLLECTION AND ANALYSIS

One review author extracted data using a standardised extraction form, and another checked them. Two authors independently assessed risk of bias and the quality of the evidence. We contacted study authors to obtain measures of variance and conducted meta-analyses where possible. We synthesised data at three time points: 18 to 24 months (T1), 25 to 48 months (T2) and 49 to 72 months (T3).

MAIN RESULTS

Twelve studies involving 27,482 participants met the inclusion criteria. Interventions were either mandatory or voluntary and included up to 10 discrete components in varying combinations. All but one study took place in North America. Although we searched for parental health outcomes, the vast majority of the sample in all included studies were female. Therefore, we describe adult health outcomes as 'maternal' throughout the results section. We downgraded the quality of all evidence at least one level because outcome assessors were not blinded. Follow-up ranged from 18 months to six years. The effects of welfare-to-work interventions on health were generally positive but of a magnitude unlikely to have any tangible effects.At T1 there was moderate-quality evidence of a very small negative impact on maternal mental health (standardised mean difference (SMD) 0.07, 95% Confidence Interval (CI) 0.00 to 0.14; N = 3352; studies = 2)); at T2, moderate-quality evidence of no effect (SMD 0.00, 95% CI 0.05 to 0.05; N = 7091; studies = 3); and at T3, low-quality evidence of a very small positive effect (SMD -0.07, 95% CI -0.15 to 0.00; N = 8873; studies = 4). There was evidence of very small positive effects on maternal physical health at T1 (risk ratio (RR) 0.85, 95% CI 0.54 to 1.36; N = 311; 1 study, low quality) and T2 (RR 1.06, 95% CI 0.95 to 1.18; N = 2551; 2 studies, moderate quality), and of a very small negative effect at T3 (RR 0.97, 95% CI 0.91 to 1.04; N = 1854; 1 study, low quality).At T1, there was moderate-quality evidence of a very small negative impact on child mental health (SMD 0.01, 95% CI -0.06 to 0.09; N = 2762; studies = 1); at T2, of a very small positive effect (SMD -0.04, 95% CI -0.08 to 0.01; N = 7560; studies = 5), and at T3, there was low-quality evidence of a very small positive effect (SMD -0.05, 95% CI -0.16 to 0.05; N = 3643; studies = 3). Moderate-quality evidence for effects on child physical health showed a very small negative effect at T1 (SMD -0.05, 95% CI -0.12 to 0.03; N = 2762; studies = 1), a very small positive effect at T2 (SMD 0.07, 95% CI 0.01 to 0.12; N = 7195; studies = 3), and a very small positive effect at T3 (SMD 0.01, 95% CI -0.04 to 0.06; N = 8083; studies = 5). There was some evidence of larger negative effects on health, but this was of low or very low quality.There were small positive effects on employment and income at 18 to 48 months (moderate-quality evidence), but these were largely absent at 49 to 72 months (very low to moderate-quality evidence), often due to control group members moving into work independently. Since the majority of the studies were conducted in North America before the year 2000, generalisabilty may be limited. However, all study sites were similar in that they were high-income countries with developed social welfare systems.

AUTHORS' CONCLUSIONS

The effects of WtW on health are largely of a magnitude that is unlikely to have tangible impacts. Since income and employment are hypothesised to mediate effects on health, it is possible that these negligible health impacts result from the small effects on economic outcomes. Even where employment and income were higher for the lone parents in WtW, poverty was still high for the majority of the lone parents in many of the studies. Perhaps because of this, depression also remained very high for lone parents whether they were in WtW or not. There is a lack of robust evidence on the health effects of WtW for lone parents outside North America.

The tyranny of the averages and the indiscriminate use of risk factors in public health: The case of coronary heart disease

Modern medicine is overwhelmed by a plethora of both established risk factors and novel biomarkers for diseases. The majority of this information is expressed by probabilistic measures of association such as the odds ratio (OR) obtained by calculating differences in average “risk” between exposed and unexposed groups. However, recent research demonstrates that even ORs of considerable magnitude are insufficient for assessing the ability of risk factors or biomarkers to distinguish the individuals who will develop the disease from those who will not. In regards to coronary heart disease (CHD), we already know that novel biomarkers add very little to the discriminatory accuracy (DA) of traditional risk factors. However, the value added by traditional risk factors alongside simple demographic variables such as age and sex has been the subject of less discussion. Moreover, in public health, we use the OR to calculate the population attributable fraction (PAF), although this measure fails to consider the DA of the risk factor it represents. Therefore, focusing on CHD and applying measures of DA, we re-examine the role of individual demographic characteristics, risk factors, novel biomarkers and PAFs in public health and epidemiology. In so doing, we also raise a more general criticism of the traditional risk factors’ epidemiology. We investigated a cohort of 6103 men and women who participated in the baseline (1991–1996) of the Malmö Diet and Cancer study and were followed for 18 years. We found that neither traditional risk factors nor biomarkers substantially improved the DA obtained by models considering only age and sex. We concluded that the PAF measure provided insufficient information for the planning of preventive strategies in the population. We need a better understanding of the individual heterogeneity around the averages and, thereby, a fundamental change in the way we interpret risk factors in public health and epidemiology.

•

There is a plethora of differences in “average” risk between exposed and unexposed groups of individuals.

•

Individual heterogeneity around average values is seldom considered in Public Health.

•

Measures of discriminatory accuracy (DA) informs on the underlying individual heterogeneity.

•

Most know risk factors and other categorizations associated with diseases have low DA.

•

We need a fundamental change in the way we investigate risk factors and other categorizations in Public Health.

When Null Hypothesis Significance Testing Is Unsuitable for Research: A Reassessment

Null hypothesis significance testing (NHST) has several shortcomings that are likely contributing factors behind the widely debated replication crisis of (cognitive) neuroscience, psychology, and biomedical science in general. We review these shortcomings and suggest that, after sustained negative experience, NHST should no longer be the default, dominant statistical practice of all biomedical and psychological research. If theoretical predictions are weak we should not rely on all or nothing hypothesis tests. Different inferential methods may be most suitable for different types of research questions. Whenever researchers use NHST they should justify its use, and publish pre-study power calculations and effect sizes, including negative findings. Hypothesis-testing studies should be pre-registered and optimally raw data published. The current statistics lite educational approach for students that has sustained the widespread, spurious use of NHST should be phased out.

Perspective: Improving Nutritional Guidelines for Sustainable Health Policies: Current Status and Perspectives

A large body of evidence supports the notion that incorrect or insufficient nutrition contributes to disease development. A pivotal goal is thus to understand what exactly is appropriate and what is inappropriate in food ingestion and the consequent nutritional status and health. The effective application of these concepts requires the translation of scientific information into practical approaches that have a tangible and measurable impact at both individual and population levels. The agenda for the future is expected to support available methodology in nutrition research to personalize guideline recommendations, properly grading the quality of the available evidence, promoting adherence to the well-established evidence hierarchy in nutrition, and enhancing strategies for appropriate vetting and transparent reporting that will solidify the recommendations for health promotion. The final goal is to build a constructive coalition among scientists, policy makers, and communication professionals for sustainable health and nutritional policies. Currently, a strong rationale and available data support a personalized dietary approach according to personal variables, including sex and age, circulating metabolic biomarkers, food quality and intake frequency, lifestyle variables such as physical activity, and environmental variables including one's microbiome profile. There is a strong and urgent need to develop a successful commitment among all the stakeholders to define novel and sustainable approaches toward the management of the health value of nutrition at individual and population levels. Moving forward requires adherence to well-established principles of evidence evaluation as well as identification of effective tools to obtain better quality evidence. Much remains to be done in the near future.

Comparative effects of the restriction method in two large observational studies of body mass index and mortality among adults

BACKGROUND

A method applied in some large studies of weight and mortality is to begin with a well-defined analytic cohort and use successive restrictions to control for methodologic bias and arrive at final analytic results.

MATERIALS AND METHODS

Two observational studies of body mass index and mortality allow a comparative assessment of these restrictions in very large data sets. One was a meta-analysis of individual participant data with a sample size of 8 million. The second was a study of a South Korean cohort with a sample size of 12 million. Both presented results for participants without pre-existing disease before and after restricting the sample to never-smokers and deleting the first 5 years of follow-up.

RESULTS

Initial results from both studies were generally similar, with hazard ratios (HRs) below 1 for overweight and above 1 for underweight and obesity. The meta-analysis showed higher HRs for overweight and obesity after the restrictions, including a change in the direction of the HR for overweight from 0·99 (95% CI: 0·98-1·01) to 1·11 (95% CI: 1·10, 1·11). The South Korean data showed little effect of the restrictions and the HR for overweight changed from 0·85 (95% CI: 0·84-0·86) to 0·91 (95% CI: 0·90, 0·91). The summary effect size for overweight was 0·90 (95% CI: 0·89-0·91) before restrictions and 1·02 (95% CI: 1·02, 1·03) after restrictions.

CONCLUSIONS

The effect of the restrictions is not consistent across studies, weakening the argument that analyses without such restrictions lack validity.

Why clinical trial outcomes fail to translate into benefits for patients

Clinical research should ultimately improve patient care. For this to be possible, trials must evaluate outcomes that genuinely reflect real-world settings and concerns. However, many trials continue to measure and report outcomes that fall short of this clear requirement. We highlight problems with trial outcomes that make evidence difficult or impossible to interpret and that undermine the translation of research into practice and policy. These complex issues include the use of surrogate, composite and subjective endpoints; a failure to take account of patients' perspectives when designing research outcomes; publication and other outcome reporting biases, including the under-reporting of adverse events; the reporting of relative measures at the expense of more informative absolute outcomes; misleading reporting; multiplicity of outcomes; and a lack of core outcome sets. Trial outcomes can be developed with patients in mind, however, and can be reported completely, transparently and competently. Clinicians, patients, researchers and those who pay for health services are entitled to demand reliable evidence demonstrating whether interventions improve patient-relevant clinical outcomes.

Why clinical trial outcomes fail to translate into benefits for patients

Clinical research should ultimately improve patient care. For this to be possible, trials must evaluate outcomes that genuinely reflect real-world settings and concerns. However, many trials continue to measure and report outcomes that fall short of this clear requirement. We highlight problems with trial outcomes that make evidence difficult or impossible to interpret and that undermine the translation of research into practice and policy. These complex issues include the use of surrogate, composite and subjective endpoints; a failure to take account of patients' perspectives when designing research outcomes; publication and other outcome reporting biases, including the under-reporting of adverse events; the reporting of relative measures at the expense of more informative absolute outcomes; misleading reporting; multiplicity of outcomes; and a lack of core outcome sets. Trial outcomes can be developed with patients in mind, however, and can be reported completely, transparently and competently. Clinicians, patients, researchers and those who pay for health services are entitled to demand reliable evidence demonstrating whether interventions improve patient-relevant clinical outcomes.

Ecoinformatics (Big Data) for Agricultural Entomology: Pitfalls, Progress, and Promise

Ecoinformatics, as defined in this review, is the use of preexisting data sets to address questions in ecology. We provide the first review of ecoinformatics methods in agricultural entomology. Ecoinformatics methods have been used to address the full range of questions studied by agricultural entomologists, enabled by the special opportunities associated with data sets, nearly all of which have been observational, that are larger and more diverse and that embrace larger spatial and temporal scales than most experimental studies do. We argue that ecoinformatics research methods and traditional, experimental research methods have strengths and weaknesses that are largely complementary. We address the important interpretational challenges associated with observational data sets, highlight common pitfalls, and propose some best practices for researchers using these methods. Ecoinformatics methods hold great promise as a vehicle for capitalizing on the explosion of data emanating from farmers, researchers, and the public, as novel sampling and sensing techniques are developed and digital data sharing becomes more widespread.

Worldwide Exposures to Cardiovascular Risk Factors and Associated Health Effects: Current Knowledge and Data Gaps

Information on exposure to, and health effects of, cardiovascular disease (CVD) risk factors is needed to develop effective strategies to prevent CVD events and deaths. Here, we provide an overview of the data and evidence on worldwide exposures to CVD risk factors and the associated health effects. Global comparative risk assessment studies have estimated that hundreds of thousands or millions of CVD deaths are attributable to established CVD risk factors (high blood pressure and serum cholesterol, smoking, and high blood glucose), high body mass index, harmful alcohol use, some dietary and environmental exposures, and physical inactivity. The established risk factors plus body mass index are collectively responsible for ≈9.7 million annual CVD deaths, with high blood pressure accounting for more CVD deaths than any other risk factor. Age-standardized CVD death rates attributable to established risk factors plus high body mass index are lowest in high-income countries, followed by Latin America and the Caribbean; they are highest in the region of central and eastern Europe and central Asia. However, estimates of the health effects of CVD risk factors are highly uncertain because there are insufficient population-based data on exposure to most CVD risk factors and because the magnitudes of their effects on CVDs in observational studies are likely to be biased. We identify directions for research and surveillance to better estimate the effects of CVD risk factors and policy options for reducing CVD burden by modifying preventable risk factors.

The magnitude and temporal changes of response in the placebo arm of surgical randomized controlled trials: a systematic review and meta-analysis

BACKGROUND

Understanding changes in the placebo arm is essential for correct design and interpretation of randomized controlled trials (RCTs). It is assumed that placebo response, defined as the total improvement in the placebo arm of surgical trials, is large; however, its precise magnitude and properties remain to be characterized. To the best of our knowledge, the temporal changes in the placebo arm have not been investigated. The aim of this paper was to determine, in surgical RCTs, the magnitude of placebo response and how it is affected by duration of follow-up.

METHODS

The databases of MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov were searched from their inception to 20 October 2015 for studies comparing the efficacy of a surgical intervention with placebo. Inclusion was not limited to any particular condition, intervention, outcome or patient population. The magnitude of placebo response was estimated using standardized mean differences (SMDs). Study estimates were pooled using random effects meta-analysis. Potential sources of heterogeneity were evaluated using stratification and meta-regression.

RESULTS

Database searches returned 88 studies, but for 41 studies SMDs could not be calculated, leaving 47 trials (involving 1744 participants) eligible for inclusion. There were no temporal changes in placebo response within the analysed trials. Meta-regression analysis showed that duration of follow-up did not have a significant effect on the magnitude of the placebo response and that the strongest predictor of placebo response was subjectivity of the outcome. The pooled effect in the placebo arm of studies with subjective outcomes was large (0.64, 95% CI 0.5 to 0.8) and remained significantly different from zero regardless of the duration of follow-up, whereas for objective outcomes, the effect was small (0.11, 95% CI 0.04 to 0.26) or non-significant across all time points.

CONCLUSIONS

This is the first study to investigate the temporal changes of placebo response in surgical trials and the first to investigate the sources of heterogeneity of placebo response. Placebo response in surgical trials was large for subjective outcomes, persisting as a time-invariant effect throughout blinded follow-up. Therefore, placebo response cannot be minimized in these types of outcomes through their appraisal at alternative time points. The analyses suggest that objective outcomes may be preferable as trial end-points. Where subjective outcomes are of primary interest, a placebo arm is necessary to control for placebo response.

Optimizing the use of intravenous magnesium sulfate for acute asthma treatment in children

BACKGROUND

Asthma is the most common pediatric chronic disease and currently affects 7.1 million children in the United States. Many children experience acute asthma exacerbations. Many children also require hospitalization despite treatment in an emergency department with current standard therapy (corticosteroids, albuterol, and ipratropium). These hospitalizations may be avoided if effective adjunctive therapies can be developed to adequately treat severe exacerbations.

METHODS

Publications were searched in the PubMed database using the following keywords: magnesium AND asthma AND children AND randomized controlled trial. A total of 30 publications were returned. References of relevant articles were also screened. We included publications of controlled randomized trials where intravenous magnesium sulfate was studied in children (age < 18 years) with acute asthma (n = 7). We excluded studies in adults or trials with other formulations of magnesium (e.g., nebulized).

RESULTS

Previous studies have demonstrated that intravenous magnesium sulfate (IV MgSO₄ ) significantly improves respiratory function and reduces hospitalization rate in children with moderate to severe asthma exacerbations. Current dosing regimens involve a short infusion of 25-75 mg/kg over 20 min (maximum 2-2.5 g/dose), though no studies have directly compared dosages for relative efficacy. Several studies suggest utilizing a peak plasma concentration of magnesium higher than 4 mg/dL as a surrogate of efficacy. This review summarizes the literature regarding the use of IV MgSO₄ for the treatment of pediatric acute asthma.

CONCLUSIONS

We suggest that optimized dosing regimens could be developed using a linked pharmacokinetic-pharmacodynamic modeling and simulation approach. We propose the factors that should be considered in future clinical trial design in order to better understand the use of IV MgSO₄ in pediatric acute asthma. Pediatr Pulmonol. 2016;51:1414-1421. © 2016 Wiley Periodicals, Inc.

Diet, body size, physical activity and risk of prostate cancer: An umbrella review of the evidence

The existing literature on the relationship between diet, body size, physical activity and prostate cancer risk was summarised by the World Cancer Research Fund Continuous Update Project (CUP). An evaluation of the robustness of this evidence is required to help inform public health policy. The robustness of this evidence was evaluated using several criteria addressing evidence strength and validity, including the statistical significance of the random effects summary estimate and of the largest study in a meta-analysis, number of prostate cancer cases, between-study heterogeneity, 95% prediction intervals, small-study effects bias, excess significance bias and sensitivity analyses with credibility ceilings. A total of 248 meta-analyses were extracted from the CUP, which studied associations of 23 foods, 31 nutrients, eight indices of body size and three indices of physical activity with risk of total prostate cancer development, mortality or cancer development by stage and grade. Of the 176 meta-analyses using a continuous scale to measure the exposures, no association presented strong evidence by satisfying all the aforementioned criteria. Only the association of height with total prostate cancer incidence and mortality presented highly suggestive evidence with a 4% higher risk per 5 cm greater height (95% confidence interval, 1.03, 1.05). Associations for body mass index, weight, height, dietary calcium and spirits intake were supported by suggestive evidence. Overall, the association of diet, body size, physical activity and prostate cancer has been extensively studied, but no association was graded with strong evidence.

Commentary: Epidemiology in the era of big data

Big Data has increasingly been promoted as a revolutionary development in the future of science, including epidemiology. However, the definition and implications of Big Data for epidemiology remain unclear. We here provide a working definition of Big Data predicated on the so-called "three V's": variety, volume, and velocity. From this definition, we argue that Big Data has evolutionary and revolutionary implications for identifying and intervening on the determinants of population health. We suggest that as more sources of diverse data become publicly available, the ability to combine and refine these data to yield valid answers to epidemiologic questions will be invaluable. We conclude that while epidemiology as practiced today will continue to be practiced in the Big Data future, a component of our field's future value lies in integrating subject matter knowledge with increased technical savvy. Our training programs and our visions for future public health interventions should reflect this future.

Can Sibling Sex Ratios Be Used as a Valid Test for the Prenatal Androgen Hypothesis of Autism Spectrum Disorders?

BACKGROUND

Sibling sex ratios have been applied as an indirect test of a hypothesized association between prenatal testosterone levels and risk for autism, a developmental disorder disproportionately affecting males. Differences in sibling sex ratios between those with and without autism would provide evidence of a shared risk factor for autism and offspring sex. Conclusions related to prenatal testosterone, however, require additional assumptions. Here, we used directed acyclic graphs (DAGs) to clarify the elements required for a valid test of the hypothesis that sibling sex ratios differ between children with and without autism. We then conducted such a test using a large, population-based sample of children.

METHODS

Over 1.1 million subjects, born in California from 1992-2007, and identified through birth records, were included. The association between autism diagnosis, determined using the administrative database of the California Department of Developmental Services, and the sex of the subsequent sibling was examined using generalized estimating equations. Sources of potential bias identified using DAGs were addressed.

RESULTS

Among male children with autism, 52.2% of next-born siblings were brothers, versus 51.0% for unaffected males. For females with autism, 50.2% of following siblings were brothers versus 51.2% among control females. The relative risk of a subsequent male sibling associated with autism diagnosis was 1.02 (95% confidence interval: 0.99, 1.04).

CONCLUSIONS

In a large, population-based sample we failed to find evidence suggesting an excess of brothers among children with autism while controlling for several threats to validity. This test cannot rule out a role of any given exposure, including prenatal testosterone, in either risk of autism or offspring sex ratio, but suggests against a common cause of both.

Temporal evolution of organic carbon concentrations in Swiss lakes: trends of allochthonous and autochthonous organic carbon

Evaluation of time series of organic carbon (OC) concentrations in lakes is useful for monitoring some of the effects of global change on lakes and their catchments. Isolating the evolution of autochthonous and allochthonous lake OC might be a useful way to differentiate between drivers of soil and photosynthetic OC related changes. However, there are no temporal series for autochthonous and allochthonous lake OC. In this study, a new approach has been developed to construct time series of these two categories of OC from existing dissolved organic carbon (DOC) data. First, temporal series (longer than ten years) of OC have been compiled for seven big Swiss lakes and another 27 smaller ones and evaluated by using appropriate non-parametric statistical methods. Subsequently, the new approach has been applied to construct time series of autochthonous and allochthonous lake OC in the seven big lakes. Doing this was possible because long term series of DOC concentrations at different depths are available for these lakes. Organic carbon concentrations generally increase in big lakes and decrease in smaller ones, although only in some cases are these trends statistically significant. The magnitude of the observed changes is generally small in big lakes (<1% annual change) and larger in smaller lakes. Autochthonous DOC concentrations in big lakes increase or decrease depending on the lake and the station but allochthonous DOC concentrations generally increase. This pattern is consistent with an increase in the OC input from the lakes' catchments and/or an increase in the refractoriness of the OC in question, and with a temporal evolution of autochthonous DOC depending on the degree of recovery from past eutrophication of each particular lake. In small lakes, OC dynamics are mainly driven by decreasing biological productivity, which in many, but not all cases, outweighs the probable increase of allochthonous OC.

Industry-sponsored clinical research outside high-income countries: an empirical analysis of registered clinical trials from 2006 to 2013

Background

Industry-sponsored clinical trials, in the past performed almost exclusively in more developed countries, now often recruit participants globally. However, recruitment from outside high-income countries may not represent the ultimate target population for the intervention. Clinical trial registries provide an opportunity to quantify and examine the type of clinical research performed in various geographic regions. We sought to characterize industry-sponsored randomized controlled trials conducted in high-income countries and to compare these trials to those performed outside high-income countries.

Methods

Clinical trial data on all industry-funded randomized controlled trials conducted between 2006 and 2014 were obtained from the registry ClinicalTrials.gov. Trials were classified according to their study sites as conducted in high or non-high income countries, and data on trial characteristics were collected.

Results

Of 22,511 relevant trials, a total of 6,085 (27.0 %) trials included study sites outside a high-income country, and 2,045 (9.1 %) were conducted exclusively outside high-income countries. Of country groups, Central Europe had the greatest number of trials (3,127), followed by Eastern Europe (2,075). The percentage of trials with study sites outside high-income countries remained relatively constant over the study period. Studies with sites outside high-income countries tended to recruit more participants (median enrolled participants 265 vs. 71, P <0.001), to be longer (median study duration 20 vs. 13 months, P <0.05), and to study more advanced phase interventions (Phase 3 or 4 trial 58 % vs. 33 %, P <0.001).

Conclusions

More than a quarter of industry-sponsored trials include participants from outside high-income countries and this rate remained stable over the 7-year study period. Trials conducted outside high-income countries tend to be larger, have a longer duration, and study later phase interventions compared to studies performed exclusively in high-income countries.

Electronic supplementary material

The online version of this article (doi:10.1186/s12961-015-0019-6) contains supplementary material, which is available to authorized users.

Temporal trends in organic carbon content in the main Swiss rivers, 1974-2010

Increases in dissolved organic carbon (DOC) concentrations have often been reported in rivers and lakes of the Northern Hemisphere over the last few decades. High-quality organic carbon (OC) concentration data have been used to study the change in DOC and total (TOC) organic carbon concentrations in the main rivers of Switzerland (Rhône, Rhine, Thur and Aar) between 1974 and 2010. These rivers are characterized by high discharge regimes (due to their Alpine origin) and by running in populated areas. Small long term trends (a general statistically significant decrease in TOC and a less clear increase in DOC concentrations), on the order of 1% of mean OC concentration per year, have been observed. An upward trend before 1999 reversed direction to a more marked downward trend from 1999 to 2010. Of the potential causes of OC temporal variation analysed (water temperature, dissolved reactive phosphorus and river discharge), only discharge explains a significant, albeit still small, part of TOC variability (8-31%), while accounting for barely 2.5% of DOC variability. Estimated anthropogenic TOC and DOC loads (treated sewage) to the rivers could account for a maximum of 4-20% of the temporal trends. Such low predictability is a good example of the limitations faced when studying causality and drivers behind small variations in complex systems. River export of OC from Switzerland has decreased significantly over the period. Since about 5.5% of estimated NEP of Switzerland is exported by the rivers, riverine OC fluxes should be taken into account in a detailed carbon budget of the country.

Body mass index categories in observational studies of weight and risk of death

The World Health Organization (Geneva, Switzerland) and the National Heart, Lung, and Blood Institute (Bethesda, Maryland) have developed standard categories of body mass index (BMI) (calculated as weight (kg)/height (m)(2)) of less than 18.5 (underweight), 18.5-24.9 (normal weight), 25.0-29.9 (overweight), and 30.0 or more (obesity). Nevertheless, studies of BMI and the risk of death sometimes use nonstandard BMI categories that vary across studies. In a meta-analysis of 8 large studies that used nonstandard BMI categories and were published between 1999 and 2014 and included 5.8 million participants, hazard ratios tended to be small throughout the range of overweight and normal weight. Risks were similar between subjects of high-normal weight (BMI of approximately 23.0-24.9) and those of low overweight (BMI of approximately 25.0-27.4). In an example using national survey data, minor variations in the reference category affected hazard ratios. For example, choosing high-normal weight (BMI of 23.0-24.9) instead of standard normal weight (BMI of 18.5-24.9) as the reference category produced higher nonsignificant hazard ratios (1.05 vs. 0.97 for men and 1.06 vs. 1.02 for women) for the standard overweight category (BMI of 25.0-29.9). Use of the standard BMI groupings avoids problems of ad hoc and post hoc category selection and facilitates between-study comparisons. The ways in which BMI data are categorized and reported may shape inferences about the degree of risk for various BMI categories.