Assessing the relevance of mental health factors in fibromyalgia severity: A data-driven case study using explainable AI.

BACKGROUND AND OBJECTIVE: Fibromyalgia is a chronic disease that causes pain and affects patients' quality of life. Current treatments focus on pharmacological therapies for pain reduction. However, patients' psychological well-being is also affected, with depression and pain catastrophizing being common. This research addresses the clinicians' need to assess the influence of mental health factors on FM severity compared to pain factors. METHODS: A co-development study between FM clinicians and data scientists analyzed data from 166 FM-diagnosed patients to assess the influence of mental health factors on FM severity in comparison to pain factors. The study used the Polysymptomatic Distress Scale (PDS) and Fibromyalgia Impact Questionnaire (FIQ) as FM severity indicators and collected 15 variables including regarding demographics, pain intensity perceived, and mental health factors. The team used an author's developed framework to identify the optimal FM severity classifier and explainability by selecting a number of features that lead to obtaining the best classification result. Machine learning classifiers employed in the framework were: decision trees, logistic regression, support vector machines, random forests, AdaBoost, extra trees, and RUSBoost. Explainability analyses were conducted using the following explainable AI techniques: SHapley Additive exPlanations (SHAP), Partial Dependence Plot (PDP), and Mean Decrease Impurity (MDI). RESULTS: A balanced random forest with 6 features achieved the best performance with PDS (AUC_ROC, mean = 0.81, std = 0.07). Being FIQ the target variable, due to the imbalance in FM severity levels, a binary and a multiclass classification approaches were considered achieving the optimal performance, respectively, a logistic regression classifier (AUC_ROC, mean = 0.83, std = 0.08) with 6 selected features, and a random forest (AUC_ROC, mean = 0.91, std = 0.04) with 8 selected features. Next, the explainability analysis determined mental health factors were found to be more relevant than pain perceived factors for FM severity. CONCLUSIONS: This study's findings, validated by clinicians, are potentially aligned with FM international guidelines that promote non-pharmacological interventions such as promoting mental well-being of FM patients.

The association between meat consumption and muscle strength index in young adults: the mediating role of total protein intake and lean mass percentage.

PURPOSE: The aim of this study was to analyse the associations between the consumption of different types of meat and the muscle strength index (MSI) and to examine whether this relationship is mediated by total protein intake (TPI) and lean mass percentage (LM%) in young adults. METHODS: We conducted a cross-sectional study with first-year university students from Castilla-La Mancha, Spain. Different types of meat consumption (total, red, processed, and white and fish) were separately evaluated using a Food-Frequency Questionnaire. MSI was determined from the handgrip and standing long jump tests. ANCOVA models were used to test the mean differences in MSI by categories of meat consumption. Serial multiple mediation models were used to explore the mediating role of TPI and LM% in the relationship between meat consumption and MSI. All analyses were adjusted for age, sex, and socioeconomic level, identified through a directed acyclic graph. Additional analyses were performed with a small subsample including alcohol intake, tobacco smoking, physical activity, cardiorespiratory fitness, and total energy intake as covariates in the multiple mediation models. RESULTS: A total of 230 students (mean age 21.1 ± 2.1 years, 66.5% women) were included in the analysis. Young adults with higher meat consumption (total, red, and white and fish) had higher MSI adjusted means than their peers with lower meat consumption (p < 0.05). These associations did not remain after controlling for TPI and LM%. In adjusted mediation analyses, a significant indirect effect was observed through TPI and LM% in the associations between each of the types of meat consumption and MSI. In the additional analyses, a greater effect of white and fish meat consumption on muscle strength through mediation of TPI and LM% was reported compared to red or processed meat consumption, and no significant effects were observed between processed meat consumption and MSI. CONCLUSION: Higher consumption of total, red, and white and fish meat was associated with increased MSI in young adults. TPI and LM% mediated this relationship.

Effectiveness of Transcranial Direct Current Stimulation Combined With Exercising in People With Fibromyalgia: A Randomized Sham-Controlled Clinical Trial.

OBJECTIVE: To evaluate the effectiveness of transcranial direct current stimulation (tDCS) combined with exercising in people with fibromyalgia. DESIGN: Randomized, triple-blind, sham-controlled, clinical trial. SETTING: Primary health care center. PARTICIPANTS: A total of 120 volunteer participants (N=120) between 18 and 65 years old and diagnosed with fibromyalgia. Four participants dropped out of the study for causes unrelated to the intervention. INTERVENTION: Participants were randomized into 3 groups (active tDCS+exercising, sham tDCS+exercising, no-intervention control). The intervention was delivered in 5 sessions over 2 weeks. MAIN OUTCOME MEASURES: Pain intensity and referred pain area after suprathreshold pressure stimulation. RESULTS: Pain intensity further decreased in the active tDCS group vs control (mean, -14.43; 95% confidence interval, -25.27 to -3.58) at post intervention, unlike the sham tDCS group. Both tDCS groups did not achieve greater reductions in referred pain vs control. In the active tDCS group, health status (mean, -14.80; 95% confidence interval, -23.10 to -6.50) and pain catastrophizing (mean, -6.68, 95% confidence interval, -11.62 to -1.73) improved at post intervention, and so did health status (mean, -8.81; 95% confidence interval, -17.11 to -0.51), pain catastrophizing (mean, -7.00; 95% confidence interval, -12.13 to -1.87), and depression (mean, -3.52; 95% confidence interval, -6.86 to -0.19) after 1 month. In the sham tDCS group, improvements were recorded in health status (mean, -13.21; 95% confidence interval, -21.52 to -4.91) and depression (mean, -3.35; 95% confidence interval, -6.35 to -0.35) at post intervention and in health status (mean, -8.77; 95% confidence interval, -17.06 to -0.47), pain catastrophizing (mean, -5.68; 95% confidence interval, -10.80 to -0.55), and depression (mean, -3.98; 95% confidence interval, -7.31 to -0.64) after 1 month. No intergroup differences were observed between active and sham tDCS. CONCLUSIONS: Active and sham tDCS improved health status, pain catastrophizing, and depression vs control, but pain intensity decreased only in the active tDCS group.

A New Approach to Assess Blinding for Transcranial Direct Current Stimulation Treatment in Patients with Fibromyalgia. A Randomized Clinical Trial.

Correct blinding is essential for preventing potential biases. The aim of this study was to assess the blinding of participants and a therapist following treatment with transcranial direct current stimulation in subjects with fibromyalgia using James' and Bang's blinding indexes. Eighty subjects were randomly allocated either active or sham stimulation groups in an intervention of five sessions lasting 20 min each. A questionnaire was delivered to both the therapist and patients after the last session to record their guess of which treatment had been applied. No differences between the groups were noted at baseline in terms of demographic or clinical data. James' BI was 0.83 (CI 95%: 0.76-0.90) for the patients and 0.55 (CI 95%: 0.45-0.64) for the therapist. Bang's BI for subjects was -0.08 (CI 95%: -0.24-0.09) and -0.8 (CI 95%: -0.26-0.1) for the active and sham transcranial direct current stimulation groups, respectively. Bang's BI for the therapist was 0.21 (CI 95%: -0.02-0.43) and 0.13 (CI 95%: -0.09-0.35) for the active and sham transcranial direct current stimulation groups, respectively. Protocols of active and sham transcranial direct current stimulation applied in this study have shown satisfactory blinding of the therapist and subjects with fibromyalgia.

Pressure-Induced Referred Pain as a Biomarker of Pain Sensitivity in Fibromyalgia.

BACKGROUND: Fibromyalgia (FM) syndrome is characterized by widespread pain, fatigue, and generalized increased pain sensitivity. Appropriate and simple pain models are methods employed to assess pain mechanisms that can potentially lead to improved treatments. Pressure pain thresholds (PPTs) or mapping the referred pain area produced by pressure stimulation at suprathreshold intensities are used to assess pain mechanisms. The optimal suprathreshold stimulation intensity to elicit referred pain with minimal discomfort for patients with FM has yet to be determined. OBJECTIVES: The aim of this study was to compare the area and intensity of pressure-induced referred pain in patients with FM as elicited by systematic increases in PPTs, compared with controls. STUDY DESIGN: Observational, crossed-section study. SETTING: Research laboratory. METHODS: Twenty-six patients with FM and 26 healthy controls, age- and gender-matched, were included. Suprathreshold stimulation was applied to the infraspinatus muscle of the dominant side at 4 different intensities (PPT +20%, +30%, +40%, and +50%), after which referred pain was evaluated by measuring the area of pain in pixels using a digital body chart and its intensity on a Visual Analog Scale. Factors related to anxiety condition, pain catastrophizing, depression, and quality of life were recorded. RESULTS: The referred pain areas were larger in the FM group compared with healthy individuals at 120% (P = 0.024), 130% (P = 0.001), 140% (P = 0.001), and 150% (P = 0.001) PPT, however, within the FM group no differences were found between the intensity of suprathreshold stimulation and the size of the referred pain areas (P = 0.135) or pain intensity (P > 0.05). There was a positive correlation between the size of referred pain areas and pain catastrophizing in the FM group (r = 0.457, P = 0.032). LIMITATIONS: This study presents some limitations, among which is the variability found in the referred pain areas. CONCLUSIONS: These findings show that referred pain induced by applying a suprathreshold pressure of 120% PPT can be a useful biomarker to assess sensitized pain mechanisms in patients suffering from FM. KEY WORDS: Referred pain, pain sensitivity, fibromyalgia, central sensitization, suprathreshold, pressure pain threshold, biomarker, facilitated pain mechanisms.

Adherence to the Mediterranean Diet and Its Association with Body Composition and Physical Fitness in Spanish University Students.

The aims of this study were to assess the association of adherence to the Mediterranean diet (MD) with physical fitness and body composition in Spanish university students and to determine the ability to predict the MD adherence of each Mediterranean Diet Adherence Screener (MEDAS) item. A cross-sectional study was performed involving 310 first-year university students. Adherence to the MD was evaluated with MEDAS-14 items. Anthropometric variables, body composition, and physical fitness were assessed. Muscle strength was determined based on handgrip strength and the standing long jump test. Cardiorespiratory fitness (CRF) was measured using the Course-Navette test. Only 24% of the university students had good adherence to the MD. The ANCOVA models showed a significant difference between participants with high adherence to the MD and those with medium and low adherence in CRF (p = 0.017) and dynamometry (p = 0.005). Logistic binary regression showed that consuming >2 vegetables/day (OR = 20.1; CI: 10.1-30.1; p < 0.001), using olive oil (OR = 10.6; CI: 1.4-19.8; p = 0.021), consuming <3 commercial sweets/week (OR = 10.1; IC: 5.1-19.7; p < 0.001), and consuming ≥3 fruits/day (OR = 8.8; CI: 4.9-15.7; p < 0.001) were the items most associated with high adherence to the MD. In conclusion, a high level of adherence to the MD is associated with high-level muscular fitness and CRF in Spanish university students.