This study aimed to investigate the longitudinal effects of anxiety, depression, and their comorbidity on physical disorders and disability in an elderly Korean population.
In total, 1,204 community-dwelling elders were evaluated at baseline, and of these 909 (75%) were re-assessed two years later. Anxiety and depression were identified at baseline using questions from the community version of the Geriatric Mental State diagnostic schedule (GMS-B3). Participants were assessed for functional disability and for 11 physical disorders both at baseline and at follow-up.
Anxiety alone was associated with the incidence of heart disease, depression alone with the incidence of asthma, and comorbid anxiety and depression with incidence of eyesight problem, persistent cough, asthma, hypertension, heart disease, and gastrointestinal problems. Comorbid anxiety and depression were associated with an increase in the number of physical disorders and the degree of disability during the two-year follow-up, compared to anxiety or depression alone or the absence of anxiety or depression.
Anxiety, depression, and particularly their comorbidity should be assessed in the elderly population considering their longitudinal effects on physical disorders and disability. Future study is required to determine whether interventions aimed at these disorders can mitigate their impacts.
The importance of mental health issues among the elderly has been recognized due to the current rapid aging of the population. Depression and anxiety are two of the most common mental health problems in later life and frequently co-occur.
To date, the impact of anxiety, depression and comorbid anxiety and depression on physical disorders has been studied primarily in working-age adult populations, and while these conditions are associated with the increased occurrence of physical disorders,
Evidence suggests that sub-threshold symptoms that are insufficient to diagnose depression and anxiety disorders are frequent in elderly,
With respect to disability, it is well established that anxiety, depression and comorbid anxiety and depression including subthreshold level is associated with higher disability in late-life. However, prior literature has examined the independent impact of depression on disability in longitudinal study of elderly
This study was carried out as a part of a larger prospective community-based study of late-life psychiatric morbidity in Gwangju, South Korea, from 2001 to 2003, the details of which have been described in a previous publication.
Anxiety and depression at baseline were assessed using the community version of the Geriatric Mental State Schedule (GMS-B3) together with a diagnostic algorithm, the Automated Geriatric Examination for Computer-Assisted Taxonomy (AGECAT).
Physical disorders and functional disability were assessed both at baseline and at follow-up. Physical disorders were identified using a structured questionnaire which asked participants about the presence of 11 health problems common among the elderly: arthritis or rheumatism; eyesight problems; hearing difficulty or deafness; persistent cough; breathlessness, difficulty breathing or asthma; high blood pressure; heart disease or angina; gastric or intestinal problems; fainting or blackouts; paralysis, weakness, or loss of power in one leg or arm; and skin disorders such as pressure sores, leg ulcers, or severe burns. This questionnaire was specifically developed for estimating general health in elderly populations.
A range of sociodemographic and clinical characteristics potentially associated with anxiety and depression were also measured at baseline.
The distributions of anxiety and depressive states at baseline were tabulated, and for each condition, participants were classified into one of three categories: no anxiety/depression; sub-threshold anxiety/depression; or clinical levels of anxiety/depression. Three categories of disorders were utilized: anxiety only, depression only, and comorbid anxiety and depression. A three by three table was created depicting the number and percent of participants in each category, by disorder classification as well as degree of each disorder. For the purpose of association analyses with physical disorders and disability, the categories for sub-threshold and clinical levels were collapsed into a single category for each disorder, as there were insufficient cases of clinically significant disorders to analyze the categories separately.
Univariate analyses (χ2 tests) were conducted between baseline anxiety/depression status and each of the baseline characteristics measured; variables that showed significant associations (p<0.05) were considered to be covariates. For the analysis of incidence of physical disorders, the sample was restricted to those without any physical disorder at baseline. The associations between baseline anxiety/depression status and individual incident physical disorders were examined using the same logistic regression model, after controlling for baseline covariates. For analysis of change in the number of physical disorders and in the WHODAS scores, the changes between baseline and follow-up scores were calculated (Δphysical disorders=total number of physical disorders at follow up-total number of physical disorders at baseline; ΔWHODAS=WHODAS scores at follow up-WHODAS scores at baseline). The associations between baseline anxiety/depression status and changes in the number of physical disorders and disability were examined using the same logistic regression model after controlling for covariates. Analyses were performed using the SPSS software package for Windows (version 21.0; IBM Inc., NY, USA).
A total of 1,204 respondents completed the baseline evaluation, and of these, 909 (75.5%) were re-assessed at follow-up. The reasons for not followed participants were as follows; 102 participants could not be contacted, 61 participants died, 51 participants refused to participate, 46 participants changed address, 19 participants were too unwell to participate and 10 participants offered insufficient data about anxiety. Follow-up participants (n=909) did not differ significantly at baseline from those not followed up (n=295) with respect to age (mean±SD, 72.4±5.7 and 73.0±6.9 years, respectively; p=0.394), gender (58% and 59% female, respectively; p=0.711), or psychological status (anxiety: 15% and 16.3%; depression: 9.5% and 12.2%; comorbid anxiety and depression: 22.8% and 23.1% respectively; p=0.437). The distribution of baseline anxiety and depression status is summarized in
Univariate analyses between anxiety/depression status and the various sociodemographic and clinical characteristics were conducted and summarized in
The incidence of physical disorders was assessed during follow-up, and the distribution of incident physical disorders by anxiety and depression status at baseline is shown in rows 1 through 11 of
Changes in the total number of physical disorders between the two study points (the total number of physical disorders at follow up-the total number of physical disorders at baseline) were also calculated, and yielded a range of −1 to +8. At follow-up, the total number of physical disorders remained unchanged in 307 (25.5%) of the 909 follow-up participants; 267 (22.2%) individuals developed one additional disorder during the follow-up period, 166 (13.8%) participants developed two new disorders, and 140 (11.6%) developed three or more new disorders during the study period. In contrast, 29 individuals (2.4%) saw their physical disorders reduced by one during this period. With respect to disability, WHODAS scores (mean±SD) were 6.6±10.79 at baseline and 20.6±20.49 at follow-up. The unadjusted association of anxiety/depression status with changes in the number of physical disorders and disability scores over the two-year period is shown in
The principal findings of this 2-year longitudinal study of community elders were that: anxiety, depression and their comorbidity were highly prevalent in Korean elderly and associated with increased incidence of different physical disorders; and comorbid anxiety and depression is associated with more increase in number of physical disorders and with more disability after two years compared to anxiety and depression alone as well as no anxiety and depression after adjustment.
The prevalence of anxiety, depression, and their comorbidity in our sample were high (31.2%, 33.0%, and 22.8%, respectively), consistent with previous studies of the elderly that found ranges of 15–52.3% for anxiety,
The primary findings of our study were that comorbid anxiety and depression among the elderly were associated with an increase in the occurrence of various physical disorders including eyesight problem, persistent cough, hypertension, and gastrointestinal problems, in addition to heart disease and asthma which were also associated with anxiety alone and depression alone, respectively. Despite the of lack of previous prospective studies to evaluate the impact of comorbid anxiety and depression on the development of these physical disorders in an elderly population, longitudinal studies have reported significant correlations between psychological distress including anxiety or depression and the increased risk of these physical disorders among the general population, and occasionally the elderly population as well. Consistent with our findings, a recent meta-analysis found that depression increased the rate of hypertension in the general population.
It was also found that elderly with comorbid anxiety and depression had the highest increase in number of physical disorders and highest increase in level of disability, followed by elderly people with depression or anxiety alone. Although previous cross-sectional studies have found that comorbid anxiety and depression are linked to greater functional disability and lower well-being than having depression or anxiety alone,
This study's finding that anxiety symptoms were associated with an increased incidence of heart disease at the two-year follow-up is consistent with previous studies of elderly populations that have found anxiety disorders, such as panic disorder and posttraumatic stress disorder, to be significantly associated with heart disease both cross-sectionally
The study also found that depressive symptoms were associated with greater risk of developing asthma. Although this is the first study to report a prospective association between depression and the incidence of asthma specifically in an elderly population, a meta-analysis of general adult participants followed for 8–20 years found that depression was associated with a 43% increased risk of developing asthma.
Our study is the first to report a longitudinal association between psychological symptoms, including comorbid anxiety and depression, anxiety alone, and depression alone, and the incidence of various physical disorders in an elderly community cohort. We used standardized assessment scales including WHODAS II which has been used for measuring disability encompassing functional capacity and functional ability and has been exhibited rigorous validity, reliability and cross-cultural applicability.
In conclusion, anxiety, depression, and their comorbidity are common in elderly, and comorbidity between anxiety and depression is associated with greater risk of developing various physical disorders and higher levels of disability. Clinicians and community-based social service providers should seek to identify older patients with anxiety and depression those who are at risk for various physical disorders. Additionally, researchers and clinicians should keep in mind for managing elderly with collaborative care to improve general health condition in elderly population.
This study was supported by a grant of the Korean Health Technology R&D Project, Ministry of Health & Welfare, Republic of Korea (HI12C0003). The Ministry of Health and Welfare of Korea had paper publication design; in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the paper for publication.
Data are number (%)
Data are number (%). MMSE: Mini-Mental State Examination
All ORs (95% CIs) except changes in WHODAS scores were calculated after adjustment for age, gender, education, living area, accommodation status, current employment, monthly income, marital status, physical activity, and Mini-Mental State Examination score. With respect to changes in WHODAS scores, OR (95% CIs) were calculated after adjustment for all covariates above and for total number of physical disorders. athese two variables were analyzed in a total sample size of 909, those who were followed two years later. *p<0.05, †p<0.01, ‡p<0.001. WHODAS: World Health Organization Disability Assessment Schedule, OR: odd ratio, CI: confidence interval