Combined influence of depressive symptoms and systemic inflammation on all-cause and cardiovascular mortality: evidence for differential effects by gender in the English Longitudinal Study of Ageing

A longitudinal study of the mediator role of physical activity in the bidirectional relationships of cognitive function and specific dimensions of depressive symptoms

BACKGROUND

The bidirectional relationship between cognitive function and depressive symptoms has been extensively reported. However, the potential mechanisms are still not clear. We aim to longitudinally investigate whether physical activity mediates the bidirectional relationships between cognitive function and specific dimensions of depressive symptoms.

METHODS

Data from 6,787 individuals aged ≥50 of 2014/15 (T1), 2016/17 (T2), and 2018/19 (T3) waves of the English Longitudinal Study of Ageing (ELSA). Cognitive function was assessed by domains of memory, orientation in time, and executive function. Physical activity was measured with the intensity and frequency of participation. Specific dimensions of depressive symptoms were assessed by the 8-item Center for Epidemiologic Studies Depression Scale, distinguishing between cognitive-affective and somatic symptoms. Cross-lagged panel models were used to investigate the mediating role of physical activity in the bidirectional relationships between cognitive function and two dimensions of depressive symptoms.

RESULTS

Poorer cognitive function was indirectly associated with worse cognitive-affective symptoms (indirect effect = -0.002, 95%CI: -0.004, -0.001) through lower physical activity levels. Poorer cognitive function was also indirectly associated with worse somatic symptoms (indirect effect = -0.003, 95%CI: -0.006, -0.002) through lower physical activity levels, and the reverse mediation was observed as well (indirect effect = -0.002, 95%CI: -0.004, -0.001).

LIMITATIONS

There is no distinction between potential within-person and between-person effects.

CONCLUSIONS

Collaborative interventions of physical activity are beneficial in protecting cognitive function and mental health in older adults.

Prospective association of comorbid hypertension and depressive symptoms with C-reactive protein in older adults

BACKGROUND

Hypertension and depressive symptoms often occur together in the older population, and each has been separately linked to elevated C-reactive protein (CRP). This study investigated the prospective association between comorbid hypertension and depressive symptoms and high-sensitivity CRP (hs-CRP) in a Chinese older population.

METHODS

This study used data from 4978 participants aged 50 and above, who took part in two waves (2011 and 2015) of the China Health and Retirement Longitudinal Study (CHARLS). Hypertension, depressive symptoms and hs-CRP were measured. Logistic regressions adjusted for confounding variables were used to examine the association between the baseline comorbidity of hypertension and depressive symptoms and the change in hs-CRP levels.

RESULTS

Hypertension and depressive symptoms did not show independent associations with an elevated level of hs-CRP. Participants with comorbid hypertension and depressive symptoms were more likely to develop a higher level of hs-CRP at follow-up (OR = 1.39, 95 % CI: 1.12-1.74) even after adjusting for covariates. Sex- and age-stratified analyses indicated that the association between the comorbidity and higher levels of hs-CRP were prone to be observed in women (OR = 1.55, 95 % CI: 1.16-2.08) and older adults (OR = 1.74, 95 % CI: 1.20-2.52).

CONCLUSIONS

Comorbid hypertension and depressive symptoms is related to a higher risk of elevated hs-CRP levels. This association appears to be more pronounced among women and older adults compared to their counterparts.

LIMITATION

Depression was self-reported by participants, which might be considered less unreliable than clinical diagnoses.

The interaction effect of depressive symptoms and inflammation on the occurrence of cardiovascular diseases

BACKGROUND

Whether there was an interaction effect between depressive symptoms and inflammation on the occurrence of cardiovascular diseases (CVDs) was unclear.

METHODS

In this cross-sectional study, 3346 participants in the National Health and Nutrition Examination Survey (NHANES) were included. Multivariable regression analysis was performed to explore the associations of depressive symptoms or inflammation with CVDs. The attributable proportion of interaction (API), and synergy index (SI) were applied for evaluating the statistical significance of the interaction effect.

RESULTS

Depressive symptoms were associated with 2.31-fold risk of CVDs [odds ratio (OR) = 2.31, 95 % confidence interval (CI): 1.47-3.62). The increased risk of CVDs was observed in people with neutrophil to lymphocyte ratio (NLR) ≥1.88 group (OR = 1.36, 95%CI: 1.01-1.85) and neutrophil/[white blood cell (WBC)-neutrophil] ≥1.35 (OR = 1.52, 95%CI: 1.12-2.07) after adjusting for confounders. The interaction effect of depressive symptoms and high NLR on the risk of CVDs was statistically significant with an OR value of 2.60 (95%CI: 1.43-4.70) compared to low NLR and no depressive symptoms group after adjusting for confounders. The API was 0.66 (95%CI: 0.44-0.89) and SI was 4.23 (95%CI: 2.08-8.59). The interaction effect of depressive symptoms and high neutrophil/(WBC-neutrophil) was associated with the risk of CVDs compared to low neutrophil/(WBC-neutrophil) and no depressive symptoms group (OR = 3.59, 95%CI: 2.00-6.45). The API was 0.78 (95%CI: 0.63-0.93) and SI was 6.75 (95%CI: 3.55-12.82).

CONCLUSION

There was an interaction effect of depressive symptoms and inflammation on the occurrence of CVDs.

The relationship between depression based on patient health questionaire-9 and cardiovascular mortality in patients with hypertension

BACKGROUND

Depression and hypertension are increasingly prevalent in the U.S., with evidence suggesting significant comorbidity. Despite this, the specific relationship within the U.S. hypertensive population is underexplored. Our study investigates this link using data from the 2007-2014 NHANES database and mortality data from the National Death Index.

METHODS

A total of 8677 participants were included in this cohort study. Depression diagnosis was made based on the Patient Health Questionnaire-9. Hypertension was defined either through a self-reported previous diagnosis, current antihypertensive medication use, or blood pressure exceeding standard thresholds. Cardiovascular disease mortality was determined by mortality recorded with National Death Index on December 31, 2019. The cox proportional hazards regression method was applied to analyze the association of depression with cardiovascular mortality in hypertension.

RESULTS

During an average follow-up of 8.2 years, 599 deaths were confirmed from cardiovascular disease. The association of depression with cardiovascular mortality in hypertension was significantly positive (HR, 1.0263(95%CI = 1.0033, 1.0498), p = 0.0247). In addition, the risk of cardiovascular mortality increased gradually with the severity of depressive symptoms (p for trend =0.0259). This positive relationship was basically stable in different subgroup analyses and sensitivity analyses.

LIMITATIONS

The observational design of our study hinders establishment of a causal relationship. Potential bias due to subjective reporting and the absence of depression treatment data represent limitations, although their impact on the conclusions is deemed minimal.

CONCLUSIONS

Depression is associated with cardiovascular mortality risk in patients with hypertension. The worsening depressive symptoms, the higher risk of cardiovascular mortality.

Combined influence of nutritional and inflammatory status and depressive symptoms on mortality among US cancer survivors: Findings from the NHANES

BACKGROUND

Inflammation and nutrition and depression are interrelated, and both are related to changes in mortality rates. We investigated the association of nutritional and inflammation index or depressive symptoms with the risk of all-cause mortality or cause-specific mortality among cancer survivors.

METHODS

A prospective cohort of a nationally representative sample of cancer survivors, aged 40 years or older (n = 2331; weighted population, 15 248 255; 67.6 ± 11.0 years; 50.6 % males), were recruited from the US National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018. Advanced lung cancer inflammation index (ALI) reflected inflammation and nutritional status and Patient Health Questionnaire 9 (PHQ-9) demonstrated depressive symptoms. The independent and joint associations of ALI and PHQ-9 score with mortality outcomes were examined among cancer survivors and Cox regression analysis based on weights was used to calculate the relative risk.

RESULTS

We identified 605 all-cause deaths (cancer, 204; non-cancer, 401) over a median of 6.2 years of follow-up (15,385 person-years; interquartile range, 3.3-9.8 years). High ALI was observed to be consistently associated with lower risks of all-cause (hazard ratio [HR], 0.516; 95 % CI, 0.400-0.667) and non-cancer (HR, 0.414; 95 % CI, 0.291-0.588) mortality compared with low ALI in a series of adjusted models. Meanwhile, lower PHQ-9 score (0-4) was associated with lower risks of all-cause (HR, 0.686; 95 % CI, 0.521-0.903) and non-cancer (HR, 0.686; 95 % CI, 0.474-0.992) mortality compared with higher PHQ-9 score (≥10). Furthermore, joint analyses showed that high ALI was associated with a decreased risk of death among cancer survivors who were not depressive. Specifically, survivors with high ALI but not depressive symptoms had the lowest overall (HR, 0.404; 95 % CI, 0.228-0.715) risks.

CONCLUSION

In this cohort study, we observed impact of nutritional and inflammatory status and depressive symptoms on mortality among cancer survivors, with the lowest risks of death from both all causes and non-cancer being noted among the combination of high level ALI with no depression.

Combined influence of depressive symptoms and systemic inflammation on cardiovascular diseases in China

OBJECTIVE

Previous studies had reported a significant association between depressive symptoms and inflammation. The aim of present study was to evaluate the combined effect of depressive symptoms and inflammation level on the risk of cardiovascular disease (CVD).

METHODS

A total of 9647 participants from the China Health and Retirement Longitudinal Study were included. Multivariate Cox proportional hazards regression model was used to evaluate the associations between depressive symptoms, inflammation level and new-onset CVD, stroke and cardiac events.

RESULTS

There were 1731 respondents experienced CVD (including 560 stroke and 1306 cardiac events) during the follow-up period. Compared to individuals without depressive symptoms and low hsCRP level, the adjusted hazard ratios (95% confidence intervals) were 1.23(1.09-1.38), 1.41(1.21-1.63) and 1.61(1.40-1.87) for those with high hsCRP level alone, with depressive symptoms alone, with both depressive symptoms and high hsCRP, respectively. There were additive and multiplicative effect of depressive symptoms and inflammation on the risk of CVD, stroke and cardiac events (as categorical variables). Furthermore, we found significant additive and multiplicative interactions of depressive symptoms and inflammation with CVD (as continuous variables).

CONCLUSION

Our findings indicated that there was a multiplicative effect of depressive symptoms and inflammation on the risk of CVD. Larger-sample prospective cohort studies are still required to test the potential application of combination of depressive symptoms and inflammation as a screening method to identify individuals at risk of CVD.

Combined influence of depression and low-grade inflammation on mortality in peritoneal dialysis patients

BACKGROUND

The relationship between depression and systemic inflammation as risk factors for mortality is not well understood and requires further investigation.

METHODS

Patients undergoing continuous ambulatory peritoneal dialysis (CAPD) between July 01, 2015 to December 31, 2019, were analyzed and followed up until December 31, 2020. According to their status of depression (PHQ-9 score ≥ 5) and low-grade inflammation (hs-CRP level ≥ 3 mg/L), patients were divided into four groups (G1, without depression, nor inflammation; G2, with depression, without inflammation; G3, with inflammation, without depression; G4, with both depression and inflammation). We performed Kaplan-Meier and multivariable Cox proportional analyses of mortality for the combined influence of depression and systemic inflammation in this cohort.

RESULTS

During the mean follow-up of 36.3 ± 14.8 months, 73 deaths were recorded in 358 participants. Compared with patients in group G1, patients in group G2 and G3 carried 137% {hazard ratio (HR): 2.37, 95% confidence interval (CI): 1.06-5.23, p = 0.035} and 140% (HR: 2.40, 95% CI: 1.01-5.69, p = 0.048) higher risk of mortality. Patients in group G4 (with both depression and inflammation) showed the highest risks of all-cause mortality with 276% higher mortality risk (HR: 3.76, 95% CI: 1.73-8.15, p = 0.001), respectively.

CONCLUSION

The combined of depression and inflammation is associated with all-cause mortality in peritoneal dialysis patients, suggesting a need for further study of depression and low-grade inflammation in PD patients and potential relationship between them.

New Perspectives on Treatment of Depression in Coronary Heart Disease

ABSTRACT

It has been 35 years since we published a study in Psychosomatic Medicine showing that patients with coronary heart disease (CHD) and major depression were at twice the risk of having a cardiac event as were nondepressed patients (Carney et al. Psychosom Med. 1988;50:627-33). This small study was followed a few years later by a larger, more convincing report from Frasure-Smith et al. (JAMA. 1993;270:1819-25) showing that depression increased the rate of mortality in patients with a recent acute myocardial infarction. Since the 1990s, there have been many more studies of depression as a risk factor for cardiac events and cardiac-related mortality from all over the world, and many clinical trials designed to determine whether treating depression improves medical outcomes in these patients. Unfortunately, the effects of depression treatment in patients with CHD remain unclear. This article considers why it has been difficult to determine whether treatment of depression improves survival in these patients. It also proposes several lines of research to address this question, with the goal of definitively establishing whether treating depression can extend cardiac event-free survival and enhance quality of life in patients with CHD.

Bidirectional longitudinal associations between balance performance and depressive symptoms in older adults: A cross-lagged panel model

BACKGROUND

Evidence on the temporal sequences between balance and depressive symptoms is limited, and no studies have compared the strength of each direction. This study aimed to assess the association between balance performance and depressive symptoms among community-dwelling older adults, and further to explore the driving factors in the dynamic association.

METHODS

Data were obtained from the English Longitudinal Study of Aging (ELSA). Overall, 3971 community-residing adults aged 50 years or older were assessed at 2004/05, 2008/09, and 2012/13. Balance was measured using three progressively more difficult tasks (side-by-side, semi-tandem, and full-tandem). Depressive symptoms were determined with a dichotomous eight-item version of the Center for Epidemiologic Studies Depression Scale (CES-D). Cross-lagged panel models were used to test the reciprocal relationships between balance and depressive symptoms.

RESULTS

Our analyses revealed that earlier poorer balance predicted later worse depressive symptoms consistently across waves (β_W2-W4 = -0.058, P < .05, β_W4-W6 = -0.067, P < .001). Conversely, the higher scores of depressive symptoms at wave 4 predicted lower level of balance at wave 6 (β_W4-W6 = -0.038, P = .018). The cross-lagged effects of balance on depressive symptoms were over all stronger than the reverse effects.

CONCLUSIONS

These findings add novel insights into the temporal directionality of balance and depressive symptoms among community-dwelling older adults, and suggest that a predominance of balance disorder effects. Interventional strategy should aim to increase balance ability from earlier stages to promote successful aging.

Association of depression with all-cause and cardiovascular mortality among US adults with high and low baseline risk of cardiovascular disease

The intervention of depression was considered a prevention and treatment option for cardiovascular disease (CVD). However, evidence regarding whether association of depression with mortality differed among people at high or low risk of CVD yielded conflicting results. We aimed to investigate associations between depression and all-cause and CVD mortality among 3854 and 3044 US adults at high and low baseline risk of CVD, respectively. Among participants at high risk of CVD, depression and per 5-point increase in PHQ-9 score were associated with 81% (HR=1.81, 95%CI: 1.15-2.86) and 33% (HR=1.33, 95%CI: 1.14-1.55) increased all-cause mortality, respectively. We did not find statistically significant associations between depression (HR=1.40, 95%CI: 0.67-2.95) and PHQ-9 score (HR=1.28, 95%CI: 1.00-1.63) with CVD mortality due to a small number of mortality events. Among people with low risk of CVD, each 5-point increment in PHQ-9 score was associated with all-cause mortality (HR=1.26, 95%CI: 1.02-1.56), while there was no statistically significant association of depression with all-cause mortality (HR=1.69, 95%CI: 0.75-3.81) and CVD mortality (HR=1.99, 95%CI: 0.83-4.81). This study found that depression was associated with all-cause mortality among individuals at a high baseline risk of CVD, but no significant association was observed in people at a low baseline risk of CVD.

Role of leukocytes, gender, and symptom domains in the influence of depression on hospitalization and mortality risk: Findings from the Moli-sani study

Background

Major depressive disorder is a mental illness associated with chronic conditions like cardiovascular disease (CVD). Circulating inflammation has been proposed as a potential mechanism underlying this link, although the role of specific biomarkers, gender, and symptom domains is not well elucidated.

Methods

We performed multivariable Cox regressions of first hospitalization/all-cause mortality and CVD, ischemic heart (IHD), and cerebrovascular disease (CeVD) causes vs. depression severity in an Italian population cohort (N = 13,191; age ≥ 35 years; 49.3% men; 4,856 hospitalizations and 471 deaths, median follow-up 7.28 and 8.24 years, respectively). In models adjusted for age, sex, and socioeconomic status, we estimated the proportion of association explained by C-reactive protein (CRP), platelet count, granulocyte-to-lymphocyte ratio (GLR), and white blood cell count (WBC). Gender-by-depression interaction and gender-stratified analyses were performed. Associations of polychoric factors tagging somatic and cognitive symptoms with incident clinical risks were also tested, as well as the proportion explained by a composite index of circulating inflammation (INFLA score).

Results

Significant proportions of the influence of depression on clinical risks were explained by CRP (4.8% on IHD hospitalizations), GLR (11% on all-cause mortality), and WBC (24% on IHD/CeVD hospitalizations). Gender-by-depression interaction was significantly associated only with all-cause mortality (p = 0.03), with moderate depression showing a + 60% increased risk in women, but not in men. Stable associations of somatic, but not of cognitive, symptoms with increased hospitalization risk were observed (+ 16% for all causes, + 14% for CVD causes), with INFLA score explaining small but significant proportions of these associations (2.5% for all causes, 8.6% for IHD causes).

Conclusions

These findings highlight the importance of cellular components of inflammation, gender, and somatic depressive symptoms in the link between depression and clinical (especially CVD) risks, pointing to the existence of additional pathways through which depression may play a detrimental effect on the cardiovascular system.

A Narrative Review of the Association Between Depression and Heart Disease Among Women: Prevalence, Mechanisms of Action, and Treatment

PURPOSE OF REVIEW

Sex and gender differences exist with regard to the association between depression and cardiovascular disease (CVD). This narrative review describes the prevalence, mechanisms of action, and management of depression and CVD among women, with a particular focus on coronary heart disease (CHD).

RECENT FINDINGS

Women versus men with incident and established CHD have a greater prevalence of depression. Comorbid depression and CHD in women may be associated with greater mortality, and treatment inertia. Proposed mechanisms unique to the association among women of depression and CHD include psychosocial, cardiometabolic, behavioral, inflammatory, hormonal, and autonomic factors. The literature supports a stronger association between CHD and the prevalence of depression in women compared to men. It remains unclear whether depression treatment influences cardiovascular outcomes, or if treatment effects differ by sex and/or gender. Further research is needed to establish underlying mechanisms as diagnostic and therapeutic targets.

Psychiatric symptoms and mortality in older adults with major psychiatric disorders: results from a multicenter study

Prior research suggests that certain psychiatric symptoms could be associated with increased risk of death. However, it remains unclear whether this association could rely on all or specific symptoms. In this report, we used data from a multicenter 5-year prospective study (N = 641) of older adults with an ICD-10 diagnosis of schizophrenia, bipolar disorder or major depressive disorder, recruited from French community psychiatric departments. We used a latent variable approach to disentangle the effects shared by all psychiatric symptoms (i.e., general psychopathology factor) and those specific to individual psychiatric symptoms, while adjusting for sociodemographic and clinical factors. Psychiatric symptoms were assessed face-to-face by psychiatrists trained to semi-structured interviews using the Brief Psychiatric Rating Scale (BPRS). Among older adults with major psychiatric disorders, we found that all psychiatric symptoms were associated with increased mortality, and that their effect on the 5-year mortality were exerted mostly through a general psychopathology dimension (β = 0.13, SE = 0.05, p < 0.05). No BPRS item or lower order factor had a significant effect on mortality beyond and above the effect of the general psychopathology factor. Greater number of medical conditions, older age, male sex, and being hospitalized or institutionalized at baseline were significantly associated with this risk beyond the effect of the general psychopathology factor. Since psychiatric symptoms may affect mortality mainly through a general psychopathology dimension, biological and psychological mechanisms underlying this dimension should be considered as promising targets for interventions to decrease excess mortality of older individuals with psychiatric disorders.

Adiposity and Smoking Mediate the Relationship Between Depression History and Inflammation Among Young Adults

BACKGROUND

Depression is associated with inflammation, but the mechanisms underlying this association are unclear. We examined adiposity and smoking as potential pathways through which childhood depression may lead to an elevated inflammatory status among young adults.

METHODS

The sample included 294 subjects with histories of depression (probands), 270 never-depressed siblings of probands (high-risk siblings), and 169 controls. C-reactive protein (CRP), interleukin-6 (IL-6), and soluble intercellular adhesion molecule-1 (sICAM-1) were assessed in serum samples. An adiposity score was computed from body mass index and waist circumference. Smoking behavior was evaluated during an interview. Mixed-effects models were used to test whether adiposity and smoking mediate the relationship between depression and inflammation.

RESULTS

Probands (p = .004), but not siblings (p = .071), had higher levels of sICAM-1 compared to controls. However, depression history and risk status had no direct effects on CRP (ps > .13) or IL-6 (ps > .16). Importantly, adiposity indirectly mediated the effect of group (probands vs. controls; siblings vs. controls) on all three inflammatory markers. Smoking indirectly mediated the effect of group (probands vs. controls; siblings vs. controls) on sICAM-1 only.

CONCLUSIONS

Among young adults, the adverse inflammatory consequences of depression history are significant for sICAM-1. Adiposity and smoking are pathways through which depression can indirectly impact several inflammatory markers, suggesting possible preventive interventions to improve the immunologic and cardiovascular health of depression-prone individuals.

Does inflammation mediate the effects of depression on heart disease? That may depend on the symptoms

Preparation of this manuscript was supported in part by grant number R01HL089336 from the National Heart, Lung, and Blood Institute of the National Institutes of Health, Bethesda, Maryland USA, Robert M. Carney.

Does older subjective age predict poorer cognitive function and higher risk of dementia in middle-aged and older adults?

As a biopsychosocial marker of aging, subjective age (i.e., the age individuals feel regardless of their actual age) was related to many health issues in the elderly. The purpose of this study is to investigate whether subjective age is associated with subsequent cognition and dementia risk in middle-aged and older adults. Samples were drawn from the English Longitudinal Study of Ageing (ELSA). Participants reported their subjective ages at the baseline (2004/2005), and their cognitive functions were measured after 10 years (2014/2015). Newly diagnosed dementias were recorded between 2006/2007 to 2014/2015. Overall, 6,475 adults aged 50 years or older were included in the current analyses. The relationship between subjective age reported at baseline and cognition assessed ten years later was modeled using multiple linear regression models. Compared to participants who reported a younger subjective age, those who reported an older subjective age were more likely to have poorer cognition after ten years (β = -0.705, P = .002 for memory, β = -1.567, P = .001 for executive function). A Cox proportional hazard regression model suggested that older subjective age was an independent risk factor for incident dementia (HR = 1.737, 95% CI =1.060-2.848). Other than chronological age, subjective age could also be considered as an important predictor for the development of cognitive dysfunction.

White blood cell count as a mediator of the relationship between depressive symptoms and all-cause mortality: A community-based cohort study

BACKGROUND AND OBJECTIVES

One possible pathway by which depressive symptoms influence all-cause mortality is through their relationship with markers of inflammatory response. We aimed to examine whether white blood cell (WBC) count mediated the relationship between the presence of depressive symptoms and all-cause mortality among older Chinese people.

METHODS

This community-based cohort study targeted 4053 individuals aged 60 years or over. A bootstrapping approach was applied to examine whether WBC count mediated the relationship between the presence of depressive symptoms and all-cause mortality. WBC count was evaluated as a mediator. The presence of depressive symptoms was assessed by the nine-item Patient Health Questionnaire (PHQ-9). The mediating effect was considered significant if the 95% confidence interval (CI) did not include 0.

RESULTS

Mediation analysis indicated that WBC count played an important mediating role in the relationship between PHQ-9 score and all-cause mortality based on the significance of indirect effect (β = -0.0039, 95% CI = -0.01, -0.0009). The direct effect from PHQ-9 score to all-cause mortality was not statistically significant (P = 0.11) after adjusting for WBC count.

CONCLUSION

WBC count was associated with depressive symptoms and all-cause mortality. The association of depressive symptoms with all-cause mortality was fully mediated by WBC count.

Combined influence of depression severity and low-grade inflammation on incident hospitalization and mortality risk in Italian adults

BACKGROUND

Depression and low-grade systemic inflammation are associated risk factors for hospitalizations and mortality, although the nature of this relationship is under-investigated.

METHODS

We performed multivariable Cox regressions of first hospitalization/mortality for all and specific causes vs depression severity, in an Italian population cohort (N=13,176; age≥35 years; 49.4% men), incrementally adjusting for sociodemographic, health and lifestyle factors. We tested potential mediation, additive and interactive effects of INFLA-score, a composite circulating inflammation index, and potential concurrent mediations of main lifestyles and chronic conditions.

RESULTS

Over 4,856 hospitalizations (median follow-up 7.28 years), we observed an increased incident risk of events by 24% (CI=17-32%) and 59% (30-90%) for moderate and severe depression, which also showed a 125% (33-281%) increased risk of all-cause mortality (over 471 deaths, 8.24 years). These remained stable after adjustment for lifestyles, health conditions and INFLA-score, which explained 2.1%, 7.6%, 16.3% and 8%, 14.9% and 12% of depression influence on hospitalizations and mortality risk, respectively. These proportions remained substantially stable after reciprocal adjustments. INFLA-score showed significant additive (but not interactive) effects on both hospitalizations and mortality risk.

LIMITATIONS

Depression severity was defined using a sub-version of Patient Health Questionnaire 9, which was validated here. Directionality links among exposures could not be established since they were collected simultaneously.

CONCLUSIONS

These findings suggest a combined influence of depression and low-grade inflammation on health, which is partly intertwined and dependent on lifestyles and chronic conditions. This suggests the existence of pathways other than inflammation through which depression may play its detrimental effect.

C-reactive protein mediates the association between leisure-time physical activity and lung function in middle-aged and older adults

Background

Although previous studies have reported the benefits of physical activity (PA) to lung function in middle-aged and older adults, the biological mechanisms are still unclear. This study aimed to assess the extent to which C-reactive protein (CRP) mediates the association between leisure-time PA and lung function.

Methods

A population-based sample was recruited from English Longitudinal Study of Ageing (ELSA), Wave 6 (2012–2013). PA was self-reported by questionnaires. CRP was analyzed from peripheral blood. Lung function parameters including forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were measured by using a spirometer. Baron and Kenny’s causal steps method and multiple linear regression models based on the Karlson/Holm/Bree (KHB) method were used to assess the mediating effect.

Results

Among 6875 participants, 28.4% were classified into low PA, 49.8% into moderate PA, and 21.8% into high PA. Multiple linear regression models suggested that higher PA was associated with lower levels of CRP (β = − 0.048, P = 0.002 for moderate PA; β = − 0.108, P < 0.001 for high PA). CRP negatively correlated with FEV1 (β = − 0.180, P < 0.001) and FVC (β = − 0.181, P < 0.001). Higher levels of PA were associated with better FEV1 (β = 0.085, P < 0.001 for moderate PA; β = 0.150, P < 0.001 for high PA) and FVC (β = 0.131, P < 0.001 for moderate PA; β = 0.211, P < 0.001 for high PA). After introducing the CRP into the models, regression coefficients of PA with FEV1 (β = 0.077, P < 0.001 for moderated PA; β = 0.130, P < 0.001 for high PA) and FVC (β = 0.123, P < 0.001 for moderated PA; β = 0.188, P < 0.001 for high PA) decreased. The indirect effect of high PA on lung function via CRP was significant, with 9.42–12.99% of the total effect being mediated.

Conclusions

The association between PA and lung function is mediated by CRP, suggesting that this association may be partially explained by an inflammation-related biological mechanism. This finding highlights the possible importance of PA in systemic inflammation and lung function, thus, middle-aged and older adults should be encouraged to enhance PA levels.

Associations between depressive symptoms, cigarette smoking, and cardiovascular health: Longitudinal results from CARDIA

INTRODUCTION

Depression is associated with increased risk of incident and recurrent cardiovascular disease, while the association between depression and cardiovascular health (CVH) remains unknown. Because the natural course of depression varies widely, different patterns of depression, as well as co-occurring factors such as cigarette smoking, may influence this relationship. We examined potential interactions between longitudinal patterns of depression and smoking with CVH.

METHODS

Using data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, we modeled trajectories of depression (Center for Epidemiologic Studies Depression scale scores; Years 5, 10, 15, 20) and smoking (cigarettes/day; Years 0, 2, 5, 7, 10, 15, 20). We calculated a modified American Heart Association (AHA) CVH Score (weight, blood glucose, cholesterol, blood pressure, physical activity, and diet; Year 20); higher scores indicate better CVH. Generalized linear models evaluated associations between depression trajectories, smoking trajectories, and their interaction with CVH Score.

RESULTS

The depression trajectory x smoking trajectory interaction was not associated with CVH Score, but main effects of depression trajectory (p < .001) and smoking trajectory (p < .001) were observed. Participants with patterns of subthreshold depression (β = -0.26, SE=0.08), increasing depression (β = -0.51 SE = 0.14), and high depression (β = -0.65, SE = 0.32) had lower CVH Scores than those without depression. Compared to never smokers, participants who quit smoking had higher CVH Scores (β = 0.38, SE = 0.11), while participants with the greatest smoking exposure had lower CVH Scores (β = -0.49, SE = 0.22).

LIMITATIONS

CVH Scores were adapted from the AHA guidelines based on the available CARDIA data.

CONCLUSIONS

Deleterious depression and smoking trajectories are independently but not synergistically associated with worse CVH.