Time, space and form: Necessary for causation in health, disease and intervention?

Hip Manipulation Increases Electromyography Amplitude and Hip Joint Performance: A Double-Blind Randomized Controlled Study

(1) Background: Activation of the gluteus medius (GM) muscle while minimizing the involvement of the tensor fascia latae (TFL) is crucial in treating many lower limb and lumbar spine injuries. Previous studies have demonstrated the effectiveness of joint manipulations in regulating muscle activity. The main objective of this study was to evaluate the effects of hip joint manipulation (HJM) on the muscle strength and activity (GM and TFL) of hip abductors in asymptomatic young participants. (2) Methods: The study followed a double-blind randomized controlled design. Thirty healthy, physically active women and men, free from spinal and lower limb injuries, voluntarily participated. The participants were allocated to two groups: those allocated to the HJM intervention and those in the control group receiving a sham intervention. They were assessed before and after the intervention using surface electromyography to measure muscle activation (EMGRMS) of the GM and TFL during maximal voluntary isometric hip abduction. (3) Results: HJM resulted in a significant increase in EMGRMS amplitude solely within the GM muscle (p < 0.01); (4) Conclusions: This study suggests that HJM may increase EMGRMS amplitude in the GM muscle; however, the effects are neither statistically nor clinically significant when compared to the control group for most of the muscles analyzed.

Temporal uncertainty in disease diagnosis

There is a profound paradox in modern medical knowledge production: The more we know, the more we know that we (still) do not know. Nowhere is this more visible than in diagnostics and early detection of disease. As we identify ever more markers, predictors, precursors, and risk factors of disease ever earlier, we realize that we need knowledge about whether they develop into something experienced by the person and threatening to the person's health. This study investigates how advancements in science and technology alter one type of uncertainty, i.e., temporal uncertainty of disease diagnosis. As diagnosis is related to anamnesis and prognosis it identifies how uncertainties in all these fields are interconnected. In particular, the study finds that uncertainty in disease diagnosis has become more subject to prognostic uncertainty because diagnosis is more connected to technologically detected indicators and less closely connected to manifest and experienced disease. These temporal uncertainties pose basic epistemological and ethical challenges as they can result in overdiagnosis, overtreatment, unnecessary anxiety and fear, useless and even harmful diagnostic odysseys, as well as vast opportunity costs. The point is not to stop our quest for knowledge about disease but to encourage real diagnostic improvements that help more people in ever better manner as early as possible. To do so, we need to pay careful attention to specific types of temporal uncertainty in modern diagnostics.

What is manipulation? A new definition

BACKGROUND

Definitions are important in healthcare. Unfortunately, problems can be found withall existing definitions of manipulation.

METHODS

This paper derives a set of eligibility criteria from prior definitions of manipulation to inform what should (and should not) be incorporated within a valid definition. These criteria were then used to select components from currently available empirical data to create a new definition.

RESULTS

The resulting definition of manipulation is: "Separation (gapping) of opposing articular surfaces of a synovial joint, caused by a force applied perpendicularly to those articular surfaces, that results in cavitation within the synovial fluid of that joint." The corresponding definition for the mechanical response of a manipulation is: "Separation (gapping) of opposing articular surfaces of a synovial joint that results in cavitation within the synovial fluid of that joint." In turn, the action of a manipulation can be defined as: "A force applied perpendicularly to the articular surfaces."

CONCLUSIONS

We believe these definitions to be valid (derived from and consistent with all available empirical data), complete (containing all necessary components), minimally sufficient (minimal redundancy, and sufficient to distinguish manipulation from other physical interventions), and robust (able to withstand important limitations embodied within sensible eligibility criteria). It is hoped that the simplicity and clarity of these definitions, and the transparency of their formation, will encourage their wide adoption in clinical, research, educational and professional settings.

How to gain evidence for causation in disease and therapeutic intervention: from Koch’s postulates to counter-counterfactuals

Researchers, clinicians, and patients have good reasons for wanting answers to causal questions of disease and therapeutic intervention. This paper uses microbiologist Robert Koch’s pioneering work and famous postulates to extrapolate a logical sequence of evidence for confirming the causes of disease: association between individuals with and without a disease; isolation of causal agents; and the creation of a counterfactual (demonstrating that an agent is sufficient to reproduce the disease anew). This paper formally introduces counter-counterfactuals, which appear to have been used, perhaps intuitively, since the time of Koch and possibly earlier. An argument is presented that counter-counterfactuals (disease-preventers) are a useful tool for identifying necessary causes of disease, and sometimes must be used in place of isolation which is not always possible. In addition, a logical sequence of causal evidence for a therapeutic intervention is presented: creating a counterfactual (demonstrating that the intervention is sufficient to change the natural course of a disease), comparisons between subjects in receipt of treatment versus those who are not (typically within a randomised controlled trial, which can quantify effects of intervention), and counter-counterfactuals (treatment-preventers, which can identify the intervention’s mechanisms of action).

Epidemiology of uveitis in a US population-based study

Background

The purpose of this study is to assess the relationship between self-reported uveitis and purported demographic and clinical risk factors, using an American adult population extracted from the National Health and Nutrition Examination Survey (NHANES) for the years 2009 and 2010. This is a cross-sectional, population-based study using a sample of 5106 subjects between 20 and 69 years old. The main outcome for our study was the self-report of a diagnosis of uveitis. The demographic analysis included age, gender, and ethnicity. Potential predictors were having a diagnosis of ankylosing spondylitis (AS), ulcerative colitis (UC), or Crohn’s disease (CD); a history of cigarette smoking; vitamin D deficiency; and different mental health measures. Univariate and multivariate analyses were conducted using RStudio.

Results

Of the 5106 participants, 27 had reported a diagnosis of uveitis, showing an adjusted prevalence of 5.4 per 1000 subjects (95% CI 3.4–8.5/1000). Increased age was associated with higher uveitis prevalence in the multivariate analysis (odds ratio [OR] = 1.04, 95% CI 1.01–1.07; p = 0.02). Positive smoking history was reported in 59.2% of patients. Multivariate analysis comparing smoking with the presence of uveitis showed an OR of 3.18 (95% CI 1.59–6.37; p = 0.003), adjusting for age and gender. Moreover, 11.1% of the participants from the uveitis group self-reported a diagnosis of AS and 11.7% informed a diagnosis of UC and 7.1% of CD. The ORs were of 16.64 (95% CI 3.64-76.09; p = 0.001), 11.34 (95% CI 2.69-47.88; p = 0.003), and 22.16 (95% CI 2.64-186.17; p = 0.007), respectively when compared with the non-uveitis group in the multivariate analysis.

Conclusions

Age, cigarette smoking, AS, UC, and CD are positively associated with self-reported uveitis. There is previous evidence that smoking and female gender are positive risk factors for uveitis, as well as evidence that HLA-B27-positive spondyloarthritides have the highest association with non-infectious uveitis in the adult population in North America and Europe. However, there are no prior studies that have utilized a representative US population-based sample to validate these findings. The present study supports smoking as a risk factor, which has clinical relevance since this is a modifiable habit.

The form of causation in health, disease and intervention: biopsychosocial dispositionalism, conserved quantity transfers and dualist mechanistic chains

Causation is important when considering: how an organism maintains health; why disease arises in a healthy person; and, how one may intervene to change the course of a disease. This paper explores the form of causative relationships in health, disease and intervention, with particular regard to the pathological and biopsychosocial models. Consistent with the philosophical view of dispositionalism, we believe that objects are the fundamental relata of causation. By accepting the broad scope of the biopsychosocial model, we argue that psychological and social constructs be considered objects. We think that this 'biopsychosocial dispositionalism' offers the flexibility required to describe causation throughout health, disease and intervention pathways. When constructing mechanistic chains to describe causative pathways, we argue that an object will causally connect with others through actions; transfers of energy from one object to another, initiated by the manifestation of one or more dispositional property. Finally, our analysis of causative interactions utilises the concept that a common form of interaction exists between disease and intervention pathways. This common form will always be an object, but the mode of interaction will vary with each disease. We describe how intervention may act through objects being shared between converging mechanistic chains, or through the removal and/or insertion of objects in such chains. We believe that this analysis provides novel insight to the forms of causative transactions that can occur. In addition, we hope that the findings of this analysis represent the first step towards developing a framework for appraising the composition of mechanistic theories.

Adolescent idiopathic scoliosis and back pain

This broad narrative review addresses the relationship between adolescent idiopathic scoliosis (AIS) and back pain. AIS can be responsible for low back pain, particularly major cases. However, a linear relationship between back pain and the magnitude of the deformity cannot be expected for any individual patient. A large number of juvenile patients can remain pain-free. The long-term prognosis is rather benign for many cases and thus a tailored approach to the individual patient seems mandatory. The level of evidence available does not allow stringent recommendations for any of the disorders included in this review.

Association between self-reported bupropion use and glaucoma: a population-based study

PURPOSE

To investigate the relationship between self-reported bupropion use and self-reported glaucoma in a nationally representative sample of the US population.

METHODS

This cross-sectional study included 6760 participants in the National Health and Nutrition Examination Survey (NHANES) between 2005 and 2008, age ≥40 years, who responded to a question regarding their glaucoma status. Participants were interviewed regarding the use of prescription medications, and those ascertained as having used bupropion were further divided into groups based on duration of usage. Other relevant information, including demographics, comorbidities and health-related behaviours, was obtained via interview. Multivariate logistic regression was performed to determine the OR and 95% CIs for association between bupropion use and prevalent glaucoma. Covariates in the final multivariate model included parameters associated with glaucoma at p<0.1: age, gender, ethnicity and annual income.

RESULTS

453 participants self-reported a diagnosis of glaucoma, and 108 reported bupropion medication use. Participants who reported using bupropion for more than 1 year had decreased odds of self-reporting a diagnosis of glaucoma (unadjusted OR=0.5, 95% CI 0.01 to 0.52; adjusted OR=0.1, 95% CI 0.01 to 0.81) compared with those not using bupropion or using it for less than a year.

CONCLUSIONS

Bupropion use, particularly for an extended period of time, may be associated with a reduced risk of glaucomatous disease.