Relationships of persistent depressive symptoms with subsequent lung function trajectory and respiratory disease mortality

Excess mortality and life-years lost in people diagnosed with depression: A 20-year population-based cohort study of 126,573 depressed individuals followed for 1,139,073 persons-years

Depression is associated with premature mortality, but evidence is mainly derived from Western countries. Very limited research has evaluated shortened lifespan in depression using life-years-lost (LYLs), a recently developed mortality metric taking into account the illness onset for life expectancy estimation. Temporal trends of differential mortality gap are understudied. This population-based cohort study, which utilized a territory-wide medical-record database of public inpatient and outpatient healthcare services in Hong Kong, evaluated the extent of premature mortality in 126,573 individuals with depression (persons-years=1,139,073) between January 2002 and December 2021 regarding the standardized mortality ratio (SMR) and excess LYLs. Trends in annual SMRs over 20 years were assessed by joinpoint analyses. The results showed that individuals with depression exhibited significantly higher all-cause (SMR=1.84 [95% CI=1.82-1.88]), natural-cause (1.69 [1.66-1.72]), and unnatural-cause (5.24 [4.97-5.51]) mortality rates than the general population. Suicide-specific SMR was markedly elevated (7.92 [7.47-8.38]), particularly in the 15-34 year-olds (12.75 [10.87-14.79]). Respiratory diseases, cardiovascular diseases and cancers accounted for the majority of deaths. Excess LYLs extended to men (5.67 years, 95% CI = 5.45-5.90) and women (4.06 years, 95% CI = 3.89-4.23). Overall and natural-cause mortality rates improved over time, but unnatural-cause and suicide-related mortality gaps persisted. Taken together, this study indicates that depression is associated with increased premature mortality and reduced lifespan in a predominantly Chinese population, mainly attributed to natural causes. Relative suicide-specific mortality is substantially elevated, especially among young people. The pronounced mortality gap underscores an urgent need for effective interventions targeting improved physical health and suicide risk reduction in individuals with depression.

Association and biological pathways between lung function and incident depression: a prospective cohort study of 280,032 participants

BACKGROUND

Lung health is increasingly recognized as an essential factor in mental health. However, prospective evidence on lung function with incident depression remains to be determined. The study aimed to examine the prospective association between impaired lung function and incident depression and the underlying biological mechanisms.

METHODS

This prospective cohort study comprised 280,032 non-depressed individuals with valid lung function measurements from the UK Biobank. Lung function was assessed through the forced vital capacity (FVC) or forced expiratory volume in 1 s (FEV1). Cox proportional hazard models were applied to estimate the associations between lung function and incident depression. Mediation analyses were fitted to investigate the potential mediating role of biomarkers and metabolites in the association.

RESULTS

A total of 9514 participants (3.4%) developed depression during a median follow-up of 13.91 years. Individuals in the highest quartile had a lower risk of depression (FVC % predicted: HR = 0.880, 95% CI = 0.830-0.933; FEV1% predicted: HR = 0.854, 95% CI = 0.805-0.905) compared with those in the lowest quartile of the lung function indices. Additionally, the restricted cubic splines suggested lung function indices had reversed J-shaped associations with incident depression (nonlinear P < 0.05 for FVC % predicted and FEV1% predicted). Impaired lung function yielded similar risk estimates (HR = 1.124, 95% CI = 1.074-1.176). Biomarkers involving systemic inflammation, erythrocytes, and liver and renal function may be potential mediators in the lung function-depression association.

CONCLUSIONS

This study revealed that the higher risk of developing depression was associated with impaired lung function. Also, the association might be partially mediated by biomarkers including systemic inflammation, erythrocytes, and liver and renal function, though these mediation findings should be interpreted with caution due to potential temporal ambiguity.

Comparative analysis of pulmonary function in school-going adolescents: Examining the impact of depression and anxiety

Objectives

Given the rising concern over depression and anxiety among adolescents, this study aims to investigate their potential impact on respiratory health by comparing pulmonary function test (PFT) parameters between healthy adolescents and those with either depression or anxiety or those exhibiting symptoms of both depression and anxiety.

Materials and Methods

In this cross-sectional study, a random sample of school-going adolescents aged 13-18 years from various schools in Sikkim, both males and females, were selected. Depression and anxiety were assessed using the Revised Children's Anxiety and Depression Scale-25, and pulmonary function was measured using a computerised spirometer-Spirolab III. The recorded variables included forced vital capacity (FVC), forced expiratory volume in 1st second (FEV1), FEV1/FVC ratio, peak expiratory flow rate (PEFR) and forced expiratory flow at 25-75% (FEF 25-75%).

Results

Significant differences emerged in FVC (P = 0.034), PEFR (P = 0.013) and FEF 25-75% (P = 0.023) between healthy and depressed adolescents aged 13-18 years. Similarly, a significant difference was observed in PEFR (P = 0.022) and FEF 25-75% (P = 0.002) between healthy adolescents and those with symptoms of both depression and anxiety. These differences were more pronounced among students in higher grades. Furthermore, significant differences in PEFR (P = 0.015) and FEF 25-75% (P ≤ 0.001) were found while comparing healthy males and males with symptoms of both depression and anxiety. However, no such disparities were seen in girls. There was no significant difference in any of the parameters when compared between the healthy group and those with anxiety.

Conclusion

Depressed adolescents exhibited significantly reduced FVC, PEFR and FEF 25-75% compared to their healthy counterparts, despite being otherwise healthy. This negative association was more pronounced in the higher age group. However, anxious adolescents did not show any significant difference in PFT compared to healthy peers.

Enhanced polygenic risk score incorporating gene-environment interaction suggests the association of major depressive disorder with cardiac and lung function

BACKGROUND

Depression has been linked to an increased risk of cardiovascular and respiratory diseases; however, its impact on cardiac and lung function remains unclear, especially when accounting for potential gene-environment interactions.

METHODS

We developed a novel polygenic and gene-environment interaction risk score (PGIRS) integrating the major genetic effect and gene-environment interaction effect of depression-associated loci. The single nucleotide polymorphisms (SNPs) demonstrating major genetic effect or environmental interaction effect were obtained from genome-wide SNP association and SNP-environment interaction analyses of depression. We then calculated the depression PGIRS for non-depressed individuals, using smoking and alcohol consumption as environmental factors. Using linear regression analysis, we assessed the associations of PGIRS and conventional polygenic risk score (PRS) with lung function (N = 42 886) and cardiac function (N = 1791) in the subjects with or without exposing to smoking and alcohol drinking.

RESULTS

We detected significant associations of depression PGIRS with cardiac and lung function, contrary to conventional depression PRS. Among smokers, forced vital capacity exhibited a negative association with PGIRS (β = -0.037, FDR = 1.00 × 10-8), contrasting with no significant association with PRS (β = -0.002, FDR = 0.943). In drinkers, we observed a positive association between cardiac index with PGIRS (β = 0.088, FDR = 0.010), whereas no such association was found with PRS (β = 0.040, FDR = 0.265). Notably, in individuals who both smoked and drank, forced expiratory volume in 1-second demonstrated a negative association with PGIRS (β = -0.042, FDR = 6.30 × 10-9), but not with PRS (β = -0.003, FDR = 0.857).

CONCLUSIONS

Our findings underscore the profound impact of depression on cardiac and lung function, highlighting the enhanced efficacy of considering gene-environment interactions in PRS-based studies.