Factors Contributing to the Link between Physical Well-Being and Chronic Pain in Young People from Galicia, Northwest Spain.

Introduction: The relation between physical well-being and chronic pain is complex and involves several subjective and objective covariates. We aimed to assess the role of mediator, confounder, or interactor played by covariates, including sleep quality, physical activity, perceived stress, smoking, and alcohol drinking in the relation between physical well-being and chronic pain. Method: We used Poisson regression to obtain incidence rate ratios (IRR) of the association between physical well-being and chronic pain in a cohort study carried out among university students. We applied General Structural Equation Modeling (GSEM) to assess mediation and stratum-specific analyses to distinguish confounding from interaction. We computed Relative Excess Risks due to Interaction (RERI), Attributable Proportion (AP), and the Synergy index (S) to measure additive interaction. Results: High physical well-being is related to a large decrease in the risk of chronic pain (IRRTotal Effect = 0.58; 95% CI: 0.50-0.81). Perceived stress mediates 12.5% of the total effect of physical well-being on chronic pain. The stratum-specific IRRs of current smokers and non-current smokers were different from each other and were larger than the crude IRR (IRR = 1.49; 95% CI: 1.24-1.80), which indicates that smoking could be both confounder and interactor. Interaction analyses showed that physical activity could act as a potential interactor (RERI = 0.25; 95% CI: 0.13, 0.60). Conclusions: Perceived stress is an important mediator of the relation between physical well-being and chronic pain, while smoking is both a confounder and an interactor. Our findings may prove useful in distinguishing high-risk groups from low-risk groups, in the interventions aimed at reducing chronic pain.

Social factors and chronic pain: the modifying effect of sex in the Stockholm Public Health Cohort Study.

OBJECTIVES: To assess the relationship between social factors (socio-economic status, household load and job strain) and chronic pain occurrence, and the role of gender in this relationship. METHODS: We used data corresponding to 8 years of follow-up of the Stockholm Public Health Cohort Study (2006-2014) to compute Adjusted Incidence Rate Ratios (IRRs) and additive interaction measures of chronic pain episodes, social factors, and sex in 16 687 subjects. RESULTS: For men, increased rates of chronic pain occurrence were observed for skilled workers (IRR = 1.27, 95% CI: 0.99, 1.61) and lower non-manual employees (IRR = 1.37, 95% CI: 1.05, 1.78), compared with unskilled workers; subjects with high household load (IRR = 1.39; 95% CI: 1.03, 1.88), compared with those with a null score; and subjects with active jobs (IRR = 1.27, 95% CI: 1.06, 1.51), compared with those with low-strain jobs. For women, we observed decreased rates of chronic pain occurrence in lower (IRR = 0.82, 95% CI: 0.68, 0.99), intermediate (IRR = 0.74, 95% CI: 0.63, 0.88) and higher non-manual employees (IRR = 0.65, 95% CI: 0.54, 0.79), compared with unskilled workers. Compared with subjects with a null score, women with low household load showed a lower rate of chronic pain occurrence (IRR = 0.85; 95% CI: 0.72, 1.00). Compared with subjects with low-strain jobs, those with passive jobs (IRR = 1.21; 95% CI: 1.02, 1.44) and high-strain jobs (IRR = 1.46; 95% CI: 1.02, 2.09) showed higher rates of chronic pain occurrence. CONCLUSION: In general, our analysis yielded different, if not opposite, results when data were stratified by sex. Sex may then represent an effect modifier of the relationship between social factors and chronic pain.

Social factors and pain worsening: a retrospective cohort study.

BACKGROUND: Pain, specifically chronic pain, is a major public health issue worldwide with considerable health-related consequences and large economic impact. The relation between socioeconomic status and pain occurrence is well established. However, little is known on the relation between socioeconomic factors and worsening of pain, including progression from non-chronic pain to chronic pain. METHODS: To assess the relation between socioeconomic status and pain worsening, we used the Stockholm Public Health Cohort Study from 2006 to 2014 and analysed data of 9721 participants who completed follow-up. The adjusted incidence rate ratios (IRRs) of moderate and severe pain worsening episodes were computed, using a pain amplification model, which encompasses spreading, somatisation, and psychological distress components. Multiple imputation analysis was performed subsequently to adjust for cohort attrition. RESULTS: Compared with non-skilled workers, self-employed subjects (IRR=1.18; 95% confidence interval [CI], 1.01-1.39) and non-manual employees were at higher risk of moderate worsening (lower non-manual employees: IRR=1.21; 95% CI, 1.03-1.41; intermediate non-manual employees: IRR=1.26; 95% CI, 1.10-1.44; higher non-manual employees: IRR=1.25; 95% CI, 1.08-1.45). This risk increase was limited to worsening starting at stage 0 (non-chronic pain). No association was found between socioeconomic status and severe pain worsening. CONCLUSION: Our results support a moderate association between intermediate and high socioeconomic status, and moderate pain worsening. This association could be explained by the heterogeneous composition of the socioeconomic variable used in this cohort, and by changes in exposure and other time-varying covariables' status during follow-up.

Paracetamol Intake and Hematologic Malignancies: A Meta-Analysis of Observational Studies.

Hematologic malignancies cause more than half a million deaths every year worldwide. Analgesics were suggested as chemopreventive agents for several cancers but so far, results from individual studies about the relationship between paracetamol (acetaminophen) use and hematologic malignancies are conflicting. Therefore, we decided to perform a systematic review and meta-analysis. We retrieved studies published in any language by systematically searching Medline, Embase, Conference Proceedings Citation Index, Open Access Theses and Dissertations, and the five regional bibliographic databases of the World Health Organization until December 2020. Pooled odds ratios (OR) and their 95% confidence intervals (CI) were calculated according to the inverse of their variances. We performed separate analyses by histologic type. We also evaluated publication bias and assessed quality. A total of 17 study units met our inclusion criteria. The results show an association of hematologic malignancies with any paracetamol intake (OR 1.49, 95% CI 1.23-1.80) and with high paracetamol intake (OR 1.77, 95% CI 1.45-2.16). By subtype, risk was higher for multiple myeloma (OR 2.13, 95% CI 1.54-2.94) for any use and OR 3.16, 95% CI 1.96-5.10 for high intake, while risk was lower and non-significant for non-Hodgkin lymphoma. This meta-analysis provides evidence that paracetamol intake may be associated with hematologic malignancies and suggests that a dose-response effect is plausible. These results are unlikely to be due to publication bias or low quality of studies. Future research should focus on assessing the dose-response relationship.

Socioeconomic status and occurrence of chronic pain: a meta-analysis.

OBJECTIVE: To examine the association between socioeconomic status (SES) and the occurrence of chronic pain, defined as pain that persists or recurs for >3 months. METHODS: We performed a structured search in Medline, Embase, WHO Global Index Medicus and Conference Proceedings Citation Index-Science databases to identify cohort and case-control studies on chronic pain and SES and its subgroups (SES combined index, educational level, income and occupational status). We extracted study characteristics, outcome measures and measures of association and their 95% CIs. Literature search, data extraction and risk of bias assessment were conducted by two independent researchers. We performed main and subgroup meta-analyses using random-effects model, and formally assessed heterogeneity and publication bias. RESULTS: A total of 45 studies, covering a population of ∼175 000 individuals, were meta-analysed, yielding a pooled Odds Ratio (OR) of 1.32 (95% CI: 1.21, 1.44) and 1.16 (95% CI: 1.09, 1.23) for low and medium SES levels, respectively, compared with high level. We obtained similar results in all the subgroup analyses. Heterogeneity was generally moderate to high across strata, and some evidence of publication bias for low socioeconomic status was found. CONCLUSION: Our results support a moderate increase in the risk of chronic pain for low and medium SES when compared with high SES, a feature that remained constant in all measures of exposure or outcome used. Further prospective research on populations from developing countries are needed to confirm our findings as the studies available for this meta-analysis were carried out exclusively in developed countries.

Computerized Clinical Decision Support Systems and Antibiotic Prescribing: A Systematic Review and Meta-analysis.

PURPOSE: The aim of this study was to perform a systematic review and meta-analysis of studies performed in primary care centers and hospital facilities that evaluated the effectiveness of computerized clinical decision support systems (CDSSs) in decision making on the prescription of any given antibiotic. METHODS: We conducted a search of the MEDLINE and EMBASE databases. A meta-analysis was then conducted of all variables with results reported in >2 studies. FINDINGS: A total of 42 of the 46 studies included in the review identified a statistically significant advantage for CDSSs in ≥1 study variables. The effect of CDSSs on the percentage accuracy of the antibiotic spectrum prescribed empirically with respect to the microbial agent's susceptibility, which is one of the most frequently studied outcome variables, was examined in 7 studies, all undertaken in hospital settings. In all these studies but one, CDSSs resulted in a statistically significant increase in percentage accuracy. The other study variables present in >2 studies had more inconsistent results. Although the results of the meta-analysis of the variables percentage accuracy, antibiotic prescription rate in hospital, percentage adherence to antibiotic prescription guidelines in primary care or hospital, and percentage of inappropriate prescriptions for antibiotics in primary care were statistically significantly favorable to CDSSs; in the case of hospital length of stay and mortality, they were favorable although not statistically significantly. IMPLICATIONS: CDSSs appear to be useful for variables such as the percentage of appropriate empirical treatment in the hospital setting or to induce changes in antibiotics prescription rate. Even so, more better quality studies are required to draw clearer conclusions in respect of morbidity and mortality outcome variables and other settings.

Polyunsaturated Fatty Acids and Chronic Pain: A Systematic Review and Meta-analysis.

BACKGROUND: Chronic pain is one of the most frequent disease symptoms and represents a global health problem with a considerable economic burden. The role of polyunsaturated fatty acids (PUFA) in chronic pain conditions was debated during the last decade with conflicting results. OBJECTIVE: To assess whether polyunsaturated fatty acids intake is useful as a preventive or curative tool in chronic pain. STUDY DESIGN: Systematic review and meta-analysis. SETTING: This study examined all published studies, either preventive or curative, on PUFA supplementation and chronic pain. METHODS: We retrieved studies published in any language by searching systematically Medline, Embase, Conference Proceedings Citation Index, dissertations databases, and the 5 regional bibliographic databases of the World Health Organization until May 2015. We included both observational and intervention studies reporting effect measures and their confidence intervals of polyunsaturated fatty acids intake in the regular diet or supplementation and pain. Two investigators selected studies; extracted data independently on baseline characteristics, exposure, and outcomes; and rated the quality of interventional studies using Jadad score. We calculated pooled standardized mean differences (SMDs) of pain indexes such as the Visual Analogue Score. We further carried out subgroup analyses by disease, type of PUFA, outcome scale, quality index, dose, and time of supplementation. RESULTS: We retrieved 5 observational and 46 intervention studies. Only one observational study showed a protective effect of PUFA. On the contrary, the interventional studies yielded a pooled random effects SMD of -0.40 (95% CI -0.58, -0.22), which indicates improvement, as 0 is the value that indicates absence of effect. The largest effect was found for dysmenorrhea (SMD -0.82, 95% CI -1.21, -0.43), Ω-3 supplementation (-0.47, 95% CI -0.68, -0.26) and composite scores (-0.58, 95% CI -1.07, -0.09). Mitigation of pain was stronger for low doses (-0.55, 95% CI -0.79, -0.30) and short supplementation periods (-0.56, 95% CI -0.86, -0.25). LIMITATIONS: While the number of curative studies was large, that of preventive studies available was limited. CONCLUSION: Our results suggest that Ω-3 PUFA supplementation moderately improves chronic pain, mainly that due to dysmenorrhea. Further investigation on the preventive potential of PUFA supplementation is needed, as the amount of evidence is scarce. Key words: Meta-analysis, systematic review, chronic pain, PUFA, supplementation, Ω-3, dysmenorrhea.