Secondhand smoke exposure across the life course and the risk of adult-onset depression and anxiety disorder

Locus of control and the long-term effects of parental smoking on mental health

RATIONALE

Few studies take a life course perspective to explain if exposure to second-hand smoke in childhood influences mental health in adulthood. Importantly, no study provides empirical evidence on the pathways through which exposure to second-hand smoke in childhood influences mental health in adulthood. There is also limited evidence on the factors that moderate the relationship between second-hand smoke exposure and mental health. To inform policy, it is important to explore the pathways through which second-hand smoke influences mental health and understand factors that are likely to moderate this relationship.

OBJECTIVES

The objective of this paper is to examine if exposure to parental smoking in childhood influences mental health in adulthood. The study examines general health and smoking status in later life as potential channels and if locus of control (LoC), a personality trait developed in childhood and adolescence, moderates the relationship between exposure to parental smoking in childhood and mental health in adulthood.

METHODS

Using 21 waves of longitudinal data from the Household, Income and Labour Dynamics in Australia (HILDA), the study conducts regression analyses that adjust for the potential effects of confounders and other biases.

RESULTS

The results show that exposure to parental smoking in childhood is associated with a decline in mental health in later life, and that general health status and smoking status in adulthood are channels through which exposure to parental smoking in childhood influences mental health in adulthood. Specifically, those who are exposed to parental smoking in childhood tend to have poorer general health and a higher probability of being smokers in adulthood, both of which negatively impact mental health. The findings point to the moderating role of LoC, such that being more internal on LoC dampens the negative effects of exposure to parental smoking on mental health.

CONCLUSION

The findings from this study lend support to the need to address the long-term implications of behaviours that are harmful to health. The findings also suggest that LoC has implications for an individual's psychological resilience against the negative effects from exposure to parental smoking in childhood.

Assessing Causality Between Second-Hand Smoking and Potentially Associated Diseases in Multiple Systems: A Two-Sample Mendelian Randomization Study

INTRODUCTION

The global disease burden may be exacerbated by exposure to passive smoking (SHS), with the workplace being a primary location for such exposure. Numerous epidemiological studies have identified SHS as a risk factor for diseases affecting various systems, including cardiovascular, respiratory, immune, endocrine, and nervous systems. The conventional observational study has certain methodological constraints that can be circumvented through a Mendelian randomization (MR) study. Our MR study intends to investigate the causal link between workplace exposure to SHS and the potential associated diseases.

AIM AND METHODS

Summary statistics data involving European participants were sourced from three databases: the UK Biobank, the FinnGen study, and the European Bioinformatics Institute. Genetic variants linked with exposure to SHS in the workplace were identified as instrumental variables. The MR was carried out using inverse variance weighted (IVW), MR-Egger, and weighted median methods. Sensitivity tests were also undertaken within the MR to evaluate the validity of the causality.

RESULTS

According to the IVW model, genetically determined atrial fibrillation (AF) and stroke (p = 6.64E-04 and 5.68E-07, odds ratio = 2.030 and 2.494, 95% confidence interval = 1.350 to 3.051 and 1.743 to 3.569) were robustly associated with exposure to SHS in the workplace. Suggestive associations were found between workplace SHS and myocardial infarction (MI), asthma, and depression.

CONCLUSIONS

The MR study demonstrates that exposure to SHS in the workplace is a significant risk factor for AF and stroke in European individuals. Whether workplace exposure to SHS influences other diseases and the causality between them requires further exploration.

IMPLICATIONS

This study explored the causality between exposure to SHS in the workplace and potential associated diseases in multiple systems, including MI, AF, stroke, lung cancer, asthma, allergic disease, type 2 diabetes, and depression, using an MR study. The MR study can circumvent the methodological constraints of observational studies and establish a causal relationship. The two-sample MR analysis provides evidence supporting the causal association of frequent workplace SHS with AF and stroke. Individuals exposed to SHS in the workplace may also have a heightened risk of MI, asthma, and depression. However, whether SHS affects other diseases and the causality between them requires further investigation. To our knowledge, this is the first two-sample MR study to determine the causal relationship between SHS and potential diseases. Exposure to SHS in the workplace is a prevalent issue and may contribute to a global disease burden. The reduction of exposure following the introduction of smoke-free laws has led to a decrease in the admission rate for cardiac events and an improvement in health indicators. It is crucial to further advance smoke-free policies and their implementation.

Association between indoor air pollution and depression: a systematic review and meta-analysis of cohort studies

OBJECTIVES

Incomplete combustion of solid fuel and exposure to secondhand smoke (SHS) are the primary causes of indoor air pollution (IAP), potentially leading to detrimental effects on individual mental health. However, current evidence regarding the association between IAP and depression remains inconclusive. This study aims to systematically investigate the evidence regarding the association between IAP and the risk of depression.

DESIGN

Systematic review and meta-analysis of cohort studies.

DATA SOURCES

Two independent reviewers searched PubMed, the Cochrane Library, Web of Science and EMBASE for available studies published up to 13 January 2024.

ELIGIBILITY CRITERIA

We included all cohort studies published in English that aimed to explore the relationship between IAP from solid fuel use and SHS exposure and the risk of depression.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted data and assessed the risk of bias. The association between IAP and depression was calculated using pooled relative risk (RR) with 95% CIs. Heterogeneity was assessed using the I2 value, and the effect estimates were pooled using fixed-effects or random-effects models depending on the results of homogeneity analysis.

RESULTS

We included 12 articles with data from 61 217 participants. The overall findings demonstrated a significant association between IAP exposure and depression (RR=1.22, 95% CI: 1.13 to 1.31), although with substantial heterogeneity (I2=75%). Subgroup analyses based on pollutant type revealed that IAP from solid fuel use was associated with a higher risk of depression (RR=1.20, 95% CI: 1.13 to 1.26; I2=62%; 5 studies, 36 768 participants) than that from SHS exposure (RR=1.11, 95% CI: 0.87 to 1.41; I2=80%; 7 studies, 24 449 participants). In terms of fuel use, the use of solid fuel for cooking (RR: 1.23, 95% CI: 1.16 to 1.31; I2=58%; 4 studies, 34 044 participants) and heating (RR 1.15, 95% CI: 1.04 to 1.27; I2=65%; 3 studies, 24 874 participants) was associated with increased depression risk.

CONCLUSIONS

The findings from this systematic review and meta-analysis of cohort studies indicated an association between exposure to IAP and depression.

PROSPERO REGISTRATION NUMBER

CRD42022383285.

Association between secondhand smoke exposure across the life course and depressive symptoms among Chinese older adults

BACKGROUND

There are limited data on the association between secondhand smoke (SHS) exposure across the life course and depressive symptoms among older adults. We aimed to investigate the association of childhood household SHS exposure, adulthood household SHS exposure, lifetime social SHS exposure, and their coexistence with depressive symptoms in older adults.

METHODS

Data were from the 2011-2012 and 2014 waves of the Chinese Longitudinal Healthy Longevity Survey. About 4000 participants (aged 60 years or older) were recruited in a randomly selected half of the counties and cities in China. Data on SHS exposure, past-year depressive symptoms, and covariates were collected using a questionnaire. The chi-square test (for categorical variables) and t-test (for continuous variables) were used to assess differences in the participant characteristics across groups of SHS exposures. We estimated the odds ratios (ORs) and 95 % confidence intervals (CIs) of depressive symptom according to different types of SHS exposure.

RESULTS

Childhood household SHS exposure (OR = 1.42, 95%CI = 1.22-1.66), adulthood household SHS exposure (OR = 1.41, 95%CI = 1.21-1.63) and lifetime social SHS exposure (OR = 1.35, 95%CI = 1.14-1.58) were associated with higher odds of depressive symptoms. Additionally, those with a higher SHS exposure score had higher odds of depressive symptoms (1 point: OR = 1.56, 95%CI = 1.22-2.00; 2 points: OR = 1.77, 95%CI = 1.39-2.25; 3 points: OR = 1.83, 95%CI = 1.45-2.31). The results were similar when stratified by lifetime nonsmoking, former smoking, and current smoking.

LIMITATIONS

Retrospective design may introduce recall bias.

CONCLUSIONS

SHS exposure was associated with higher odds of depressive symptoms in older adults, with the effect seeming to be addictive.

Machine-learning model for predicting depression in second-hand smokers in cross-sectional data using the Korea National Health and Nutrition Examination Survey

Objective

Depression among non-smokers at risk of second-hand smoke (SHS) exposure has been a neglected public health concern despite their vulnerability. The objective of this study was to develop high-performance machine-learning (ML) models for the prediction of depression in non-smokers and to identify important predictors of depression for second-hand smokers.

Methods

ML algorithms were created using demographic and clinical data from the Korea National Health and Nutrition Examination Survey (KNHANES) participants from 2014, 2016, and 2018 (N = 11,463). The Patient Health Questionnaire was used to diagnose depression with a total score of 10 or higher. The final model was selected according to the area under the curve (AUC) or sensitivity. Shapley additive explanations (SHAP) were used to identify influential features.

Results

The light gradient boosting machine (LGBM) with the highest positive predictive value (PPV; 0.646) was selected as the best model among the ML algorithms, whereas the support vector machine (SVM) had the highest AUC (0.900). The most influential factors identified using the LGBM were stress perception, followed by subjective health status and quality of life. Among the smoking-related features, urine cotinine levels were the most important, and no linear relationship existed between the smoking-related features and the values of SHAP.

Conclusions

Compared with the previously developed ML models, our LGBM models achieved excellent and even superior performance in predicting depression among non-smokers at risk of SHS exposure, suggesting potential goals for depression-preventive interventions for non-smokers during public health crises.

Is secondhand smoke associated with mental health issues? A narrative review of the evidence and policy implications

Secondhand smoke (SHS) is a well-established cause of lung cancer, respiratory disease, heart disease and developmental issues in children, with an overwhelming evidence base spanning over four decades. In this narrative review, we describe studies which have also linked self-reported or cotinine-assessed SHS exposure in the home, workplace and other settings to mental health disorders including depression, suicide, anxiety, and psychological distress in children and adults, sleeping disorders, Attention Deficit Hyperactivity Disorder and behavioural issues in children, and dementia in older adults. In general, evidence indicates that SHS exposure is associated with these disorders in a dose-response manner, with higher odds reported in people who are exposed to SHS at high levels, frequently, and in the home environment. Most studies so far are cross-sectional albeit in large, nationally representative samples from various countries with a smaller number of longitudinal studies. More research is needed in this area to determine whether SHS is a direct cause of adverse mental health outcomes, and whether creating smokefree environments leads to improved mental wellbeing. In particular, more research is needed on the impact of smokefree home environments, an area which has received relatively little focus in smokefree interventions which generally target public places.

Differences in Oral Health and Generalized Anxiety Disorder According to Secondhand Smoke Exposure in Public Places

BACKGROUND

This study aims to provide basic data for minimizing exposure to secondhand smoke (SHS) by confirming the relationship between exposure to SHS and generalized anxiety disorder (GAD).

METHODS

Using the third year data of the eighth National Health and Nutrition Examination Survey, 3874 people were selected as subjects. Complex sampling analysis was applied to all analyses, and 307 people were exposed to the SHS group (SHSG) and 3567 people were not exposed to the SHS group (NSHSG). Complex sample linear regression analysis was conducted to confirm the effect of exposure to SHS on oral health and GAD.

RESULTS

Among oral-health-related factors, exposure to SHS in Korean adults was related to the presence of implants. Additionally, exposure to SHS had a significant effect on GAD despite adjusting for sociodemographic characteristics and oral-health-related factors (p < 0.05).

CONCLUSIONS

In this study, the relationship between passive smoking and GAD was confirmed. Therefore, to reduce GAD, oral health management is necessary and exposure to SHS should be minimized.

Association between secondhand smoke exposure and negative emotions among 12-15-year-old non-smoking adolescents from 63 low- and middle-income countries

BACKGROUND

Secondhand smoke (SHS) exposure is associated with negative emotions in adolescents, but the association between SHS exposure and negative emotions has been understudied, especially in low- and middle-income countries. Hence, we studied the association between SHS exposure and negative emotions among 12-15-year-old non-smoking adolescents from 63 low- and middle-income countries (LMICs).

METHODS

We calculated the pooled prevalence of SHS exposure, loneliness, and anxiety in 12-15-year-old non-smoking adolescents. Multivariable logistic regression was used to evaluate country-specific associations between SHS exposure and negative emotions, after adjusting for important confounders. Meta-analyses were performed to evaluate the overall, regional, and country-income level pooled associations.

RESULTS

Of the adolescents included in the analysis, 34.88 % had less than daily SHS exposure and 13.41 % were exposed to SHS daily. The overall prevalence of loneliness and anxiety in the adolescents was 10.51 % and 8.95 %, respectively. Exposure to SHS in the past 7 days was associated with loneliness and anxiety, with odds ratios (95 % confidence intervals) of 1.15 (1.09-1.21) and 1.24 (1.17-1.31), respectively. These positive associations were observed in girls, but not in boys. In addition, there was a positive dose-response relationship between the day of exposure to SHS and loneliness and anxiety.

LIMITATIONS

The GSHS data were obtained from a self-report questionnaire and the participants were only adolescents in school.

CONCLUSIONS

Our study revealed a positive association between SHS exposure and negative emotions among non-smoking adolescents from LMICs.

Passive exposure to e-cigarette emissions is associated with worsened mental health

BACKGROUND

Cigarette smoking, secondhand cigarette smoke (SHS) exposure, and e-cigarette use ("vaping") are each associated with increased rates of depressive symptoms and other internalizing mental health disorders. The prevalence of vaping has increased greatly, yet the mental health correlates of secondhand exposure to e-cigarette emissions are as yet to be investigated. This study examined the potential adverse mental health outcomes associated with different tobacco exposures (direct and passive), with a particular focus on the mental health correlates of secondhand exposure to e-cigarette emissions.

METHODS

The Population Assessment of Tobacco and Health Study data collected from a sample of 16,173 Wave 4 adults were used to test the hypothesis that secondhand e-cigarette emissions exposure is associated with increased odds of internalizing mental health disorders. Individuals were categorized as exclusive cigarette smokers, exclusive e-cigarette users, cigarette and e-cigarette dual users, exclusive noncombustible tobacco users, secondhand smoke exposed non-users, secondhand e-cigarette emissions exposed non-users, and non-users with no current SHS/secondhand e-cigarette aerosol exposure. Adjusted weighted logistic regression analysis was used to investigate the association between exposure type and internalizing problems as assessed by scores on the Global Appraisal of Individual Needs-Short Screener (GAIN-SS), a widely used instrument for assessing mental health problems.

RESULTS

Cigarette smokers (AOR = 2.53, 95% CI: 2.19-2.92), e-cigarette users (AOR = 3.14, 2.41-4.09), dual users (AOR = 3.37, 2.85-4.00), noncombustible tobacco users (AOR = 1.48, 1.01-2.17), SHS exposed non-users (AOR = 1.63, 1.37-1.94), and secondhand e-cigarette emissions exposed non-users (AOR = 1.43, 1.03-1.99) were each associated with increased odds of moderate to severe internalizing mental health problems as compared to unexposed non-users. Odds of internalizing problems among SHS and secondhand e-cigarette emissions exposed non-users did not differ (p = 0.46).

CONCLUSIONS

This is the first study, to our knowledge, to identify an association between recent secondhand exposure to e-cigarette emissions and mental health problems, and the risk is comparable to that of SHS. Corroboration of this relationship needs further research to explicate directionality and mechanisms underlying this association.

Secondhand smoke exposure and dyslipidemia among non-smoking adults in the United States

Dyslipidemia is a major public health challenge worldwide and whether secondhand smoke exposure (SHSE) is associated with dyslipidemia is yet to be understood. This study evaluated the relationship between SHSE and odds of dyslipidemia among adults in the United States. We identified 3064 adults who had never smoked in the 2015-2016 National Health and Nutrition Examination Survey and estimated the odds ratio and 95% confidence interval for the relationship between SHSE and odds of dyslipidemia using a multivariable adjusted-logistic regression at a two-sided p < 0.05. Overall, the mean age of respondents was 46.4 ± 18.0 years, 59.6% had dyslipidemia and 36.2% had SHSE. The odds of dyslipidemia among individuals with SHSE were 1.148 (1.147, 1.149) in the overall sample, 1.214 (1.214, 1.215) among women and 1.165 (1.163, 1.167) among men. The odds trended similarly independent of age groups: 1.130 (1.129, 1.131) for young adults (<60 years) and 1.304 (1.300, 1.308) for old adults (≥60 years). SHSE was associated with higher odds of dyslipidemia with higher odds among women and old adults. Primary intervention(s) targeted at reducing SHSE may show benefits in reducing the odds of dyslipidemia, and longitudinal studies would be necessary to clarify the association between SHSE and dyslipidemia.

Anxiety and Depression Status and Influencing Factors of MSM in the Post-COVID-19 Epidemic Period: A Cross-Sectional Study in Western China

This study aimed to explore the psychological status and influencing factors of men who have sex with men (MSM) during the stable period of the COVID-19 epidemic, to provide a reference for the mental health counseling of MSM, and to provide a scientific basis for this group to actively respond to public health emergencies. A cross-sectional survey was conducted on the demographic characteristics, epidemic experiences, risk perception, and COVID-19-related attitudes of MSM in western China, and MSM anxiety and depression were assessed by using the Anxiety Self-Rating Scale and the Center for Epidemiological Studies Depression (CES-D) Scale. The incidences of MSM anxiety and depression in the post-COVID-19 epidemic period are 21.7% and 38.0%, respectively. Logistic regression analysis showed that in terms of anxiety, high controllability of the epidemic (OR = 0.7616) is a protective factor. Thinking that they are more susceptible to COVID-19 (OR = 1.6168) and worrying about another outbreak of the epidemic (OR = 1.4793) are risk factors. In terms of depression, being able to protect themselves from being infected with COVID-19 (OR = 0.6280) is a protective factor. The role of anal sex as “0”/“0.5,” and believing that they are more susceptible to COVID-19 (OR = 1.3408) are risk factors. The sudden outbreak affected the psychological state of MSM and even caused negative feelings of anxiety and depression. These findings suggest that prevention and education should be strengthened, and effective intervention measures should be taken as soon as possible, to improve the mental health of MSM.

Objective and subjective childhood socioeconomic disadvantage and incident depression in adulthood: a longitudinal analysis in the Sister Study

Understanding of the role of objective versus subjective childhood socioeconomic disadvantage (SD) in depression onset in adulthood among women, independent of later life SD, and across birth cohorts, is limited. We examined the association between objective (i.e., household education level) and subjective (i.e., rank of family income and report of not enough food to eat) SD during childhood and diagnosis of clinical depression after age 30 among 47,055 women in the Sister Study. We used Cox proportional hazard models adjusting for women's race/ethnicity, childhood household composition, mother's age at her birth adulthood educational attainment, and calendar year of birth. Analyses were repeated stratified by 10-year birth group. A total of 8036 (17.1%) women were diagnosed with clinical depression over a mean follow-up of 24.0 (± 9.9) years. Those reporting being poor (versus well-off) or not having enough food to eat in childhood had a 1.28 (95% confidence interval (CI) 1.13, 1.44) and 1.30 (95% CI 1.21, 1.41) times higher rate of depression diagnosis, respectively, with consistent associations observed across birth year groups. An inverse association between low household education level and incident depression was observed at baseline (i.e., age 30) becoming positive over time in the total sample but only among women born between 1935-1954 in analyses stratified by 10-year birth group. Our findings suggest that subjective SD in childhood is a largely consistent predictor of depression onset among women in adulthood whereas the effects of household education level in childhood may vary across women born into different birth cohorts, and for some, across the lifecourse.

Prevalence and correlates of lifestyle behavior, anxiety and depression in Chinese college freshman: A cross-sectional survey

Objectives

First-year college students had exposure to unhealthy lifestyle behaviors that correlate with a high prevalence of anxiety and depression. Regarding to the modifiable lifestyle behaviors factors, this study investigated the prevalence and correlation of multiple lifestyle behaviors, anxiety and depression in a sample of Chinese first-year college students.

Methods

Cross-sectional data were extracted from Residents eHealth app of health lifestyle behaviors survey from September to October 2019. Anxiety, depression, eating regular meals, consumption of snacks in-between meals, consumption of fruit, dessert and sugar-sweetened beverages, smoking and secondhand smoke exposure, consuming alcohol, physical activity, sedentary time were assessed by self-report. Socio-demographic including age, gender, education, family income, religion, and health condition were captured. Logistic regression was used to explore the association of multiple lifestyle behaviors, anxiety and depression.

Results

Totally 1,017 participants were included in the study. The prevalence of anxiety and depression (from mild to severe) were 40.3% and 45.3%, respectively. In multivariable analyses, religion (believe in Buddhism, OR = 2.438, 95%CI: 1.097-5.421; believe in Christian, OR = 5.886, 95%CI: 1.604-21.597), gender (Female, OR = 1.405, 95%CI: 1.001-1.971), secondhand smoke exposure (OR = 1.089, 95%CI: 1.001-1.184), and eating regular meals (OR = 0.513, 95%CI: 0.346-0.759) were associated with anxiety. Family income (OR = 0.732, 95%CI: 0.596-0.898), eating regular meals (OR = 0.641, 95%CI: 0.415-0.990), frequency of breakfast (OR = 0.813, 95%CI: 0.690-0.959), with a chronic disease (OR = 1.902, 95%CI: 1.335-2.712), and consumption of nocturnal snack (OR = 1.337, 95%CI: 1.108-1.612) were associated with depression.

Conclusions

These results highlighted the need for early lifestyle behavior intervention, especially modifying diet patterns considering the background of religion, health condition, and social-economic status in first-year college students to improve their mental health.

Air Pollution and Long Term Mental Health

We study the long-term consequences of air pollution on mental health, using a natural experiment in Indonesia. We find that exposure to severe air pollution has significant and persistent consequences on mental health. An extra standard deviation in the pollution index raises the probability of clinical depression measured 10 years past exposure by almost 1%. Women in particular seem to be more affected, but some effects persist for men as well. Pollution exposure increases the likelihood of clinical depression for women and also the severity of depressive symptoms for both sexes. It is not clear if men are more resistant to pollution or they simply recover faster from it. Education, perceived economic status, and marriage seem to be the best mitigators for these negative effects.

The prevalence of secondhand smoke exposure and related factors among schoolchildren in Northeast Thailand

Background: The prevalence of tobacco consumption in Thailand has gradually declined; however, the prevalence of exposure to secondhand smoke (SHS) is still high. The objective of this study is to estimate the prevalence of SHS exposure and examine the association between exposure to SHS and depressive symptoms among schoolchildren, and test for moderation by the number of smokers in household.

Methods: We conducted a cross-sectional study of 1105 schoolchildren. Socioeconomics factors, depressive symptoms and exposure to SHS variables were collected. We used the chi-square test for testing the factors associated to SHS exposure. In addition, we used the Mantel Haenszel test for testing interaction effect of depression to SHS exposure by the number of smokers in home. Multiple logistic regression was used to test the factors related to SHS exposure adjusted for confounders.

Results: The prevalence of exposure to SHS was 58.2% (95%CI: 55.2, 61.1). The schoolchildren with abnormal depression status were 1.8 times more likely to have been exposed to SHS (95%CI: 1.3, 2.5). In addition, the number of smokers in the home did not modify the association between exposure to SHS and depressive symptoms (P: 0.964).

Conclusions: An association between exposure to SHS and depressive in schoolchildren was observed, but this relationship was not affected by the number of smokers in children’s homes.

A Scoping Review of Non-Occupational Exposures to Environmental Pollutants and Adult Depression, Anxiety, and Suicide

PURPOSE OF REVIEW

Despite a call for better understanding of the role of environmental pollutant influences on mental health and the tremendous public health burden of mental health, this issue receives far less attention than many other effects of pollutants. Here we summarize the body of literature on non-occupational environmental pollutant exposures and adult depression, anxiety, and suicide-in PubMed, Embase, Web of Science, and PsychINFO through the end of year 2018.

RECENT FINDINGS

One hundred twelve articles met our criteria for further review. Of these, we found 88 articles on depression, 33 on anxiety, and 22 on suicide (31 articles covered multiple outcomes). The earliest article was published in 1976, and the most frequent exposure of interest was air pollution (n = 33), followed by secondhand smoke (n = 20), metals (n = 18), noise (n = 17), and pesticides (n = 10). Other exposures studied less frequently included radiation, magnetic fields, persistent organic pollutants (POPs), volatile organic compounds, solvents, and reactive sulfur compounds. The current literature, although limited, clearly suggests many kinds of environmental exposures may be risk factors for depression, anxiety, and suicide. For several pollutants, important limitations exist with many of the studies. Gaps in the body of research include a need for more longitudinal, life-course studies, studies that can measure cumulative exposures as well as shorter-term exposures, studies that reduce the possibility of reverse causation, and mechanistic studies focused on neurotoxic exposures.

Association between second-hand smoke exposure and depression and its moderation by sex: Findings from a nation-wide population survey in Germany

BACKGROUND

Findings on the association between exposure to second-hand smoke (SHS) and depression are ambiguous. Similarly, results concerning sex-specific associations are contradictory. Using large and representative survey data from Germany, we examined whether SHS exposure is associated with depressive symptoms/major depression (MDD) and whether this association differs by sex.

METHODS

We pooled data from three waves of the German Health Update telephone surveys from 2009-2012 on 28,670 never-smokers. Information on SHS exposure was based on self-reports. The outcome was a reported diagnosis of a depressive episode/MDD in the last 12 months before the survey. Logistic regression with a sex-by-SHS interaction term adjusted for socioeconomic and health-related confounders was conducted. Interaction effects were evaluated based on average marginal effects (AME).

RESULTS

No significant association between SHS exposure and depressive episodes/MDD could be observed (adjusted OR=1.01; 95%-CI=0.86, 1.15). Male never-smokers exposed to SHS were at a significantly lower likelihood of depression than unexposed men (AME= -0.009; 95%-CI= -0.018, -0.0001). No significant differences were observed for women (AME= 0.007; 95%-CI= -0.003, 0.017).

LIMITATIONS

The association between SHS exposure and depression is prone to residual confounding. Furthermore, all information were cross-sectional and based on self-report.

CONCLUSIONS

No association between SHS exposure and depression was observed in the combined sample. Among men, the association was counterintuitive. Never-smokers exposed to SHS are presumably more frequently involved in social interactions than those not exposed which may be protective for the development of depressive symptoms. Additional research accounting for residual confounding is necessary to allow further insights into the relationship between SHS exposure and depression.

Relationship Between Secondhand Smoke Exposure and Depressive Symptoms: A Systematic Review and Dose⁻Response Meta-Analysis

Previous studies have suggested an association between secondhand smoke (SHS) exposure and risk of depressive symptoms. However, it remains unclear whether there is a dose-response relationship. The effect estimates were pooled using fixed-effect or random-effect models based on homogeneity analysis. The dose-response meta-analysis was performed by linear and non-linear regression. Subgroup analyses were conducted to explore the possible sources of heterogeneity. Twenty-four studies were included in this meta-analysis. SHS exposure was significantly associated with increased odds of depressive symptoms (odds ratio (OR) = 1.32, 95% confidence interval (CI) 1.25-1.39). For SHS exposure expressed as an ordinal variable, the dose-response meta-analysis revealed a monotonically increasing relationship between SHS exposure and depressive symptoms. A similar dose-response relationship was observed for SHS exposure expressed as a continuous variable (OR = 1.57, 95% CI = 1.26-1.87). Our findings suggest that SHS exposure is associated with increasing odds of depressive symptoms in a dose-response manner.

The association between exposure to second-hand smoke and major depressive disorder in perimenopausal women: results from apopulation-based study

PURPOSE

The aim of this study was to test the hypothesis that exposure to second-hand smoke (SHS) would be positively associated with major depressive disorder (MDD) in perimenopausal women from a population-based perspective, after adjustment for all potential confounders.

METHODS

This study used the National Health and Nutrition Examination Survey (NHANES) database, 2005-2012, to report on MDD in perimenopausal women.

RESULTS

The odds ratio (OR) for MDD increased when there was a smoker was in the home, as compared to not having a smoker in the home (aOR = 2.97, 95% confidence interval [CI] = 1.15-7.67); however, in the non-poor group, the OR for MDD showed no difference between those who had or did not have a smoker in their home. For participants who self-rated their health condition as excellent, very good or good, the OR for MDD increased; it also increased if there were smokers in the home, as compared to those without smokers in the home (aOR = 2.58, 95% CI = 1.08-6.14).

CONCLUSIONS

The present study results augment our understanding of the clinical and public health significance of SHS, as well as the role of various socioeconomic and self-rated health conditions, in perimenopausal women. Key messages An increasing OR for MDD was demonstrated with regard to health status such as CVD, chronic respiratory tract disease, arthritis, thyroid problems, lower eGFR, fair or poor self-rated health condition, and elevated CRP level. Participants who self-rated their health condition as excellent, very good or good had an increased OR for MDD. The OR also increased if the women had smokers in their home versus women who did not have smokers in the home.

Associations Between Household Secondhand Smoke Exposure and Health Problems Among Non-Smoking Adolescents in the Republic of Korea

This study examined the association between household secondhand smoke exposure (HSHSE) and health status among non-smoking adolescents in Korea using two subsamples obtained from nationally representative cross-sectional secondary data: males (n = 25,653) and females (n = 31,187). Two self-reported HSHSE measures included exposure to household secondhand smoke during the week before the survey (yes or no) and number of days of HSHSE (1-7 days); and five self-reported health problems included asthma, perceived stress, depression, suicidal ideation, and self-rated health. For each subsample, this study performed (1) multivariate logistic regressions to examine HSHSE effects on asthma, depression, and suicidal ideation; and (2) multiple linear regressions to examine HSHSE effects on perceived stress and self-rated health. The rate and number of days of HSHSE were significantly higher among females (30.1% and 3.4 days) than among males (25.9% and 3.1 days). In both subsamples, HSHSE was associated with all five health problems (ORs 1.15-1.32; βs: 0.04-0.14). An increase in the number of days of HSHSE was positively associated with (1) greater perceived stress and poorer self-rated health in both subsamples (βs: 0.01-0.04), and (2) greater odds of asthma, depression, and suicidal ideation in the female subsample (ORs 1.03-1.12). Given the findings related to the strong associations (1) between HSHSE and physical, mental, and general health problems; and (2) between days of HSHSE and a greater number of health problems in females, health professionals should actively implement interventions that encourage adult smokers to stop smoking in their homes.

Major depression and secondhand smoke exposure

BACKGROUND

Epidemiological studies have consistently linked smoking to poor mental health. Among non-smokers, some studies have also reported associations between secondhand smoke exposure and psychological symptoms. However, an association between secondhand smoke exposure and depressive disorders has not been well established.

METHODS

This analysis used cross-sectional data from a series of 10 population surveys conducted in Canada between 2003 and 2013. The surveys targeted the Canadian household population, included a brief structured interview for past year major depressive episode (MDE) and included items assessing secondhand smoke exposure. We used two-stage individual-level random-effects meta-regression to synthesize results from these surveys.

RESULTS

Over the study interval, about 20% of non-smokers reported substantial exposure to secondhand smoke. In this group, the pooled annual prevalence of MDE was 6.1% (95% CI 5.3-6.9) compared to 4.0% (95% CI 3.7-4.3) in non-smokers without secondhand smoke exposure. The crude odds ratio was 1.5 (95% CI 1.4-1.7). With adjustment for a set of potential confounding variables the odds ratio was unchanged, 1.4 (95% CI 1.2 - 1.6).

CONCLUSIONS

These results provide additional support for public health measures aimed at reducing secondhand smoke exposure. A causal connection between secondhand smoke exposure and MDEs cannot be confirmed due to the cross-sectional nature of the data. Longitudinal studies are needed to establish temporal sequencing.

Confounding and Statistical Significance of Indirect Effects: Childhood Adversity, Education, Smoking, and Anxious and Depressive Symptomatology

The life course perspective, the risky families model, and stress-and-coping models provide the rationale for assessing the role of smoking as a mediator in the association between childhood adversity and anxious and depressive symptomatology (ADS) in adulthood. However, no previous study has assessed the independent mediating role of smoking in the association between childhood adversity and ADS in adulthood. Moreover, the importance of mediator-response confounding variables has rarely been demonstrated empirically in social and psychiatric epidemiology. The aim of this paper was to (i) assess the mediating role of smoking in adulthood in the association between childhood adversity and ADS in adulthood, and (ii) assess the change in estimates due to different mediator-response confounding factors (education, alcohol intake, and social support). The present analysis used data collected from 1994 to 2008 within the framework of the Tromsø Study (N = 4,530), a representative prospective cohort study of men and women. Seven childhood adversities (low mother's education, low father's education, low financial conditions, exposure to passive smoke, psychological abuse, physical abuse, and substance abuse distress) were used to create a childhood adversity score. Smoking status was measured at a mean age of 54.7 years (Tromsø IV), and ADS in adulthood was measured at a mean age of 61.7 years (Tromsø V). Mediation analysis was used to assess the indirect effect and the proportion of mediated effect (%) of childhood adversity on ADS in adulthood via smoking in adulthood. The test-retest reliability of smoking was good (Kappa: 0.67, 95% CI: 0.63; 0.71) in this sample. Childhood adversity was associated with a 10% increased risk of smoking in adulthood (Relative risk: 1.10, 95% CI: 1.03; 1.18), and both childhood adversity and smoking in adulthood were associated with greater levels of ADS in adulthood (p < 0.001). Smoking in adulthood did not significantly mediate the association between childhood adversity and ADS in adulthood. However, when education was excluded as a mediator-response confounding variable, the indirect effect of childhood adversity on ADS in adulthood was statistically significant (p < 0.05). This study shows that a careful inclusion of potential confounding variables is important when assessing mediation.

Effects of tobacco exposure on perinatal suicidal ideation, depression, and anxiety

Background

Previous studies have stressed the importance of tobacco exposure for the mood disorders of depression and anxiety. Although a few studies have focused on perinatal women, none have specifically considered the effects of smoking and secondhand smoke exposure on perinatal suicidal ideation. Thus, this study aimed to investigate the relationships of smoking/secondhand smoke exposure status with suicidal ideation, depression, and anxiety from the first trimester to the first month post partum.

Methods

This cross-sectional study based on self-reported data was conducted at five hospitals in Taipei, Taiwan from July 2011 to June 2014. The questionnaire inquired about women’s pregnancy history, sociodemographic information, and pre-pregnancy smoking and secondhand smoke exposure status, and assessed their suicidal ideation, depression, and anxiety symptoms. Logistic regression models were used for analysis.

Results

In the 3867 women in the study, secondhand smoke exposure was positively associated with perinatal depression and suicidal ideation. Compared with women without perinatal secondhand smoke exposure, women exposed to secondhand smoke independently exhibited higher risks for suicidal ideation during the second trimester (odds ratio (OR) = 7.63; 95 % confidence interval (CI) = 3.25–17.93) and third trimester (OR = 4.03; 95 % CI = 1.76–9.23). Women exposed to secondhand smoke had an increased risk of depression, especially those aged 26–35 years (OR = 1.71; 95 % CI = 1.27–2.29).

Conclusions

Secondhand smoke exposure also considerably contributes to adverse mental health for women in perinatal periods, especially for the severe outcome of suicidal ideation. Our results strongly support the importance of propagating smoke-free environments to protect the health of perinatal women.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-3254-z) contains supplementary material, which is available to authorized users.

Relationship between Secondhand Smoking with Depressive Symptom and Suicidal Ideation in Korean Non-Smoker Adults: The Korean National Health and Nutrition Examination Survey 2010-2012

Background

Research suggests that mental health is affected not only by smoking, but also by secondhand smoking. But the most researches have been conducted in North America and/or Europe. We examined whether this relationship remains evident within the South Korean population. Specifically, we investigated the effect of secondhand smoking on depressive symptoms and suicidal ideation.

Methods

We analyzed data from 6,043 non-smoking adults who participated in the 2010–2012 Korea National Health and Nutrition Examination Survey. We compared the presence of depressive symptoms and suicidal ideation in 3,006 participants who were exposed to secondhand smoking in the office or at home with 3,037 non-exposed participants.

Results

In unadjusted logistic regression analysis, secondhand smoking exposure group had more suicidal ideations than no secondhand smoking exposure (16.1% vs. 12.2%; odds ratio [OR], 1.50; 95% confidence interval [CI], 1.241–1.804), but risk of depressive symptoms was not significantly different between two groups (15.2% vs. 12.2%; OR, 1.21; 95% CI, 0.997–1.460). In multivariate logistic regression analysis, Among those exposed to secondhand smoking, the OR for depressive symptoms was 1.02 (95% CI, 0.866–1.299) and 1.43 (95% CI, 1.139–1.802) for suicidal ideation. Overall, secondhand smoking at home was significantly related to depressive symptoms and suicidal ideation. Among females, secondhand smoking exposure at home only (not in the office) was related to depressive symptoms and suicidal ideation.

Conclusion

Exposure to secondhand smoking, especially at home, may be associated with an increase in especially in female depressive symptoms and suicidal ideation among adults in South Korea.

Secondhand smoke exposure and mental health problems in Korean adults

OBJECTIVES

To evaluate the association between secondhand smoke exposure (SHSE) and mental health problems among Korean adults.

METHODS

We analyzed data from the 2011 Korean Community Health Survey. From the total of 229,226 participants aged 19 years or above, we excluded 48,679 current smokers, 36,612 former smokers, 3,036 participants with a history of stroke, 2,264 participants with a history of myocardial infarction, 14,115 participants who experienced at least one day in bed per month due to disability, and 855 participants for whom information regarding SHSE or mental health problems was not available. The final analysis was performed with 22,818 men and 100,847 women. Participants were classified into four groups according to the duration of SHSE: none, <1 hr/d, 1-<3 hr/d, and ≥3 hr/d. The presence of depressive symptoms, diagnosed depression, and high stress were measured by questionnaire.

RESULTS

After adjusting for demographic factors, lifestyle, and chronic disease, the odds ratio (OR) and 95% confidence interval (CI) of depressive symptoms with 1-<3 hr/d and ≥3 hr/d SHSE were 1.44 (95% CI, 1.14 to 1.82) and 1.59 (95% CI, 1.46 to 1.74), respectively. However, SHSE ≥3 hr/d had a higher OR of 1.37 (95% CI, 1.20 to 1.58) for diagnosed depression. SHSE was also associated with high stress (1-<3 hr/d: OR, 1.56; 95% CI, 1.38 to 1.76; ≥3 hr/d: OR, 1.33 95% CI, 1.28 to 1.40). However, the association between SHSE and symptoms of depression and stress did not differ significantly by region.

CONCLUSIONS

SHSE may be associated with mental health problems such as depression and stress in Korean adults.

Family Smoking, Exposure to Secondhand Smoke at Home and Family Unhappiness in Children

Tobacco use adversely affects many aspects of well-being and is disliked by non-smokers. However, its association with family happiness is unknown. We investigated the associations of family unhappiness with smoking in family members and secondhand smoke (SHS) exposure at home in Hong Kong children. In a school-based survey in 2012–2013, 1238 primary school students (mean age 8.5 years, standard deviation 0.9; 42.6% boys) reported family smoking, SHS exposure at home and whether their families had any unpleasant experience caused by smoking or SHS in the past 30 days (tobacco-related unpleasant experience), and rated the overall level of happiness in their families (family unhappiness). Multivariable logistic regression was used to study the associations of tobacco-related unpleasant experience and family unhappiness with family smoking and SHS exposure at home. Tobacco-related unpleasant experience and family unhappiness were reported by 27.5% and 16.5% of students. Unpleasant experience was more strongly associated with family smoking than SHS exposure at home. Family unhappiness was associated with both family smoking (odds ratio 2.37; 95% confidence interval 1.51–3.71) and SHS exposure at home (1.82; 1.39–2.40). These results suggest a previously neglected possible impact of tobacco use on family happiness.

Active smoking and exposure to secondhand smoke and their relationship to depressive symptoms in the Korea national health and nutrition examination survey (KNHANES)

BACKGROUND

The relationship between tobacco smoking, including secondhand smoking, and depression has been assessed. The purpose of this study was to evaluate the association between secondhand smoking among current, former and never smokers and depressive symptoms. For secondhand smoking, gender differences and sources of exposure were examined.

METHODS

Data from 34,693 participants from the fourth and fifth Korean Health and Nutritional Examination Survey (2007-2012) were analyzed in 2014. Self-reported exposure to active (current, former or never) and secondhand smoking and depressive symptoms experienced during the past year were analyzed using logistic regression. The dose-response relationship between duration of secondhand smoke exposure and depression was assessed with stratification by gender and sources of exposure (at home only, at the workplace only or both).

RESULTS

Regardless of their smoking status, all women who had secondhand smoke exposure at home reported more depressive symptoms than non-smoking women without any exposure to secondhand cigarette smoking (OR 1.43, 95 % CI 1.04-1.96 for current smokers; OR 2.32, 95 % CI 1.04-5.16 for former smokers; OR 1.25, 95 % CI 1.08-1.43 for never smokers). There was also a significant dose-response pattern (p-trend <0.001) for the duration of secondhand smoke exposure at home among women. No significant association was found between smoking and depressive symptoms in men.

CONCLUSIONS

There was a significant association between secondhand smoke exposure at home and depressive symptoms in women. Secondhand smoke exposure at home was associated with depressive symptoms in a dose-response manner.

Association between environmental tobacco smoke and depression among Korean women

OBJECTIVE

To evaluate the association between environmental tobacco smoke (ETS) exposure and depression among Korean women.

METHODS

Between 2008 and 2011, we examined 731 men and 1249 women (aged 39-85 years) for the Korean Genome and Epidemiology Study (KoGES)-Kangwha. Among 1208 never-smoking women, we excluded two women taking antidepressants and five women who did not complete the Beck Depression Inventory (BDI). Therefore, we performed a cross-sectional analysis on 1201 women. ETS exposure was assessed using a self-reported questionnaire, and was classified into three groups: no exposure, occasional exposure and regular exposure. Depression was assessed using the BDI score, which ranged from 0 to 63, and the presence of depression was defined as a BDI score ≥ 10.

RESULTS

Women exposed to ETS were more likely to have depression than those without ETS exposure (p=0.019). When BDI was analysed as a continuous variable, women exposed to ETS had significantly higher BDI scores after full adjustment (overall exposure: β=1.36, p=0.013; occasional exposure: β=1.15, p=0.063; regular exposure: β=1.90, p=0.039). ETS exposure was significantly associated with depression in a dose-response manner even after adjusting for age, body mass index, menopause, socioeconomic status, lifestyle and prevalent chronic diseases. The adjusted OR for depression (95% CI) was 1.72 (1.25 to 2.37) for overall ETS exposure, 1.56 (1.09 to 2.24) for occasional exposure and 2.19 (1.30 to 3.69) for regular exposure, when compared to no exposure.

CONCLUSIONS

Exposure to ETS was associated with depression among middle aged and elderly Korean women.