Does a history of depression actually mediate smoking-related pain? Findings from a cross-sectional general population-based study

Depression mediates the relationship between smoking and pain: Evidence from a nationally representative study in a low- and middle-income country

Evidence from high-income countries suggests that depressive symptoms may mediate the relationship between smoking and pain. However, the relationship remains poorly understood for the population in low- and middle-income countries (LMICs), who account for 80% of the current tobacco consumers. Using cross-sectional data from a nationally representative longitudinal survey in China, this study conducted the mediation analysis within the structural equation model (SEM) framework. It tested the indirect effect using the Monte Carlo method. Among the 16,575 participants, 29.2% (n = 4,839) reported being current smokers, 8.5% (n = 1,412) being former smokers, and 62.3% (n = 10,324) being never smokers. Phenotypic characteristics of smokers revealed some distinct characteristics concerning smoking rates, gender, and education attainment compared with results from high-income countries. Besides, current smokers reported significantly higher pain severity than never and former smokers and more depressive symptoms compared with never smokers. The mediation analysis indicated that the self-reported pain was mediated by depressive symptoms 62.7% of the association with smoking and 82.1% of the connection to the number of years quit. However, no mediation effect of depressive symptoms was found for the relationship between the amount smoked and pain severity. This study may fill the literature gap in examining depressive symptoms' mediating role in the relationship between smoking and pain severity for LMICs.

Chronic pain: a review of its epidemiology and associated factors in population-based studies

Chronic pain is a common, complex, and distressing problem that has a profound impact on individuals and society. It frequently presents as a result of a disease or an injury; however, it is not merely an accompanying symptom, but rather a separate condition in its own right, with its own medical definition and taxonomy. Studying the distribution and determinants of chronic pain allows us to understand and manage the problem at the individual and population levels. Targeted and appropriate prevention and management strategies need to take into account the biological, psychological, socio-demographic, and lifestyle determinants and outcomes of pain. We present a narrative review of the current understanding of these factors.

Characteristics of Urban Inpatient Smokers With and Without Chronic Pain: Foundations for Targeted Cessation Programs

BACKGROUND

Cigarette smoking and chronic pain are prevalent, comorbid conditions with significant consequences for individuals and society. Despite overlap between smoking and chronic pain, and pain's role as a potential barrier to quitting, there are no validated interventions targeted for smokers with chronic pains (SWCPs).

OBJECTIVE

To compare characteristics of urban inpatient smokers with and without chronic pain to inform the development of SWCP-targeted cessation interventions.

METHODS

This study reports partial results from a randomized comparative effectiveness trial of two smoking cessation interventions (NCT01363245). Participants were enrolled at two safety net hospitals in New York, NY in 2011-2014. Data were collected from the electronic health record and an interviewer-administered survey. Participants were considered to have chronic pain if they affirmed having "long-lasting, persistent, or chronic pain in the last six months" on survey.

RESULTS

Among smokers assessed for pain (n = 1093), the prevalence of chronic pain was 44%. SWCPs were more likely to report depressive symptoms and to have a history of psychiatric diagnosis (nonsubstance related) than smokers without pain. Severe problems with mobility and with performing usual activities were more common in SWCPs. No significant difference was observed in sex, race, education, nicotine dependence level, confidence in quit ability, or history of substance misuse. Conclusions/Importance: Chronic pain in smokers admitted to safety net hospitals is prevalent and associated with hindered mobility, history of psychiatric diagnosis, and prescription opioid use. Urban safety net hospitals are an appropriate setting in which to pilot SWCP-targeted cessation programs, which should be designed with consideration for patients' psychiatric history and mobility status.

A Reciprocal Model of Pain and Substance Use: Transdiagnostic Considerations, Clinical Implications, and Future Directions

Pain and substance use are highly prevalent and co-occurring conditions that continue to garner increasing clinical and empirical interest. Although nicotine and tobacco, alcohol, and cannabis each confer acute analgesic effects, frequent or heavy use may contribute to the development and progression of chronic pain, and pain may be heightened during abstinence. Additionally, pain can be a potent motivator of substance self-administration, and it may contribute to escalating use and poorer substance-related treatment outcomes. We integrated converging lines of evidence to propose a reciprocal model in which pain and substance use are hypothesized to interact in the manner of a positive feedback loop, resulting in the exacerbation and maintenance of both conditions over time. Theoretical mechanisms in bidirectional pain-substance use relations are reviewed, including negative reinforcement, social cognitive processes, and allostatic load in overlapping neural circuitry. Finally, candidate transdiagnostic factors are identified, and we conclude with a discussion of clinical implications and future research directions.

Chronic pain, depression and cardiovascular disease linked through a shared genetic predisposition: Analysis of a family-based cohort and twin study

BACKGROUND

Depression and chronic pain are the two most important causes of disability (Global Burden of Disease Study 2013). They occur together more frequently than expected and both conditions have been shown to be co-morbid with cardiovascular disease. Although shared socio-demographic risk factors (e.g. gender, deprivation) might explain the co-morbidity of these three conditions, we hypothesised that these three long-term, highly prevalent conditions co-occur and may be due to shared familial risk, and/or genetic factors.

METHODS AND FINDINGS

We employed three different study designs in two independent cohorts, namely Generation Scotland and TwinsUK, having standardised, validated questionnaire data on the three traits of interest. First, we estimated the prevalence and co-occurrence of chronic pain, depression and angina among 24,024 participants of a population-based cohort of extended families (Generation Scotland: Scottish Family Health Study), adjusting for age, gender, education, smoking status, and deprivation. Secondly, we compared the odds of co-morbidity in sibling-pairs with the odds in unrelated individuals for the three conditions in the same cohort. Lastly, examination of similar traits in a sample of female twins (TwinsUK, n = 2,902), adjusting for age and BMI, allowed independent replication of the findings and exploration of the influence of additive genetic (A) factors and shared (C) and non-shared (E) environmental factors predisposing to co-occurring chronic widespread pain (CWP) and cardiovascular disease (hypertension, angina, stroke, heart attack, elevated cholesterol, angioplasty or bypass surgery). In the Generation Scotland cohort, individuals with depression were more than twice as likely to have chronic pain as those without depression (adjusted OR 2·64 [95% CI 2·34-2·97]); those with angina were four times more likely to have chronic pain (OR 4·19 [3·64-4·82]); those with depression were twice as likely to have angina (OR 2·20 [1·90-2·54]). Similar odds were obtained when the outcomes and predictors were reversed and similar effects seen among sibling pairs; depression in one sibling predicted chronic pain in the other (OR 1·34 [1·05-1·71]), angina predicted chronic pain in the other (OR 2·19 [1·63-2·95]), and depression, angina (OR 1·98 [1·49-2·65]). Individuals with chronic pain and angina showed almost four-fold greater odds of depression compared with those manifesting neither trait (OR 3·78 [2·99-4·78]); angina showed seven-fold increased odds in the presence of chronic pain and depression (OR 7·76 [6·05-9·95]) and chronic pain nine-fold in the presence of depression and angina (OR 9·43 [6·85-12·98]). In TwinsUK, the relationship between CWP and depression has been published (R = 0.34, p<0.01). Considering the CWP-cardiovascular relationship, the most suitable model to describe the observed data was a combination of A, C and E, with a small but significant genetic predisposition, shared between the two traits (2·2% [95% CI 0·06-0·23]).

CONCLUSION

We found an increased co-occurrence of chronic pain, depression and cardiovascular disease in two independent cohorts (general population-based cohort, twins cohort) suggesting a shared genetic contribution. Adjustment for known environmental influences, particularly those relating to socio-economic status (Generation Scotland: age, gender, deprivation, smoking, education; Twins UK: age,BMI) did not explain the relationship observed between chronic pain, depression and cardiovascular disease. Our findings from two independent cohorts challenge the concept of traditional disease boundaries and warrant further investigation of shared biological mechanisms.

Anxiety and Depression in Bidirectional Relations Between Pain and Smoking: Implications for Smoking Cessation

Pain and tobacco smoking are highly prevalent and comorbid conditions that impose considerable burdens on individuals and health care systems. A recently proposed reciprocal model suggests that these conditions interact in a bidirectional manner, resulting in greater pain and the maintenance of tobacco addiction. Anxiety and depression are common among smokers in pain and have been identified as central mechanisms of interest. There is emerging evidence that smokers with anxiety/depression may experience more severe pain and functional impairment, greater pain-induced motivation to smoke, and increased sensitivity to pain during periods of smoking abstinence. Based on empirical findings, we hypothesize that these experiences may engender expectations that abstaining from smoking will exacerbate both pain and negative affect, thus eroding self-efficacy for smoking cessation and increasing perceived barriers to quitting. The goal of this narrative review is to examine the role of anxiety/depression in complex pain-smoking relations so as to advance evolving theoretical perspectives and inform the development of tailored interventions.