Associations between Physical Disability and Chronic Diseases with Depressive Symptoms in Vietnamese-Origin Older Adults in the United States

1. Introduction

A high prevalence of depressive symptoms among older adults (≥65 years) has been well-documented as it is a public health concern throughout the world [1]. Studies have found similar patterns among older adults across racial/ethnic groups that show having more chronic diseases is associated with increased levels of depressive symptoms [2,3,4]. Other studies have also found that older adults experience more depressive symptoms if they have some disability in addition to chronic diseases [5,6]. Arthritis, lung disease, stroke, and cancer have been associated with depressive symptoms among non-Hispanic Whites [7]. Black older adults with kidney disease were more likely to experience depressive symptoms in one study [8]. Diabetes, arthritis, and kidney disease have been associated with depressive symptoms among older Mexican Americans [9]. Among Chinese American older adults, depressive symptoms have been associated with hypertension, arthritis, high cholesterol, diabetes, and heart disease [10]. However, there is a paucity of information regarding the association of chronic diseases with depressive symptoms among refugee populations such as Vietnamese in the United States (U.S.).

Vietnamese Americans are one of the most recently arrived but rapidly growing Asian-origin populations, and currently the 4^th largest Asian subgroup in the U.S.[11]. Their substantial immigration started about 48 years ago, after the fall of Saigon in 1975 and many have settled in California and Texas [12]. Currently, over 2.2 million Vietnamese-origin Americans live in the U.S., and their number is growing [13]. Studies of Vietnamese Americans are important due to their lifelong adversity such as a long civil war, traumatic escape from Vietnam, boat journeys, pirate attacks, and government camps [14]. After migration to the U.S., they often faced low socioeconomic status, low English language proficiency, and cultural and lifestyle barriers [13]. These adverse experiences certainly impact aspects of physical, mental, and cognitive health and have a multi-generational impact [15]. However, the health of Vietnamese-origin people in the U.S. has not received significant attention in the literature.

To address these knowledge gaps, we developed the Vietnamese Aging and Care Survey (VACS) and collected demographic and comprehensive health data on Vietnamese older adults and their family caregivers (N=199; VACS 1) in 2018 in Houston, Texas [16,17,18,19]. In 2021, 102 older adults and their family caregivers (N=204) participated in a follow-up study [20]. Houston has over 143,000 residents of Vietnamese origin, making it the 2^nd largest Vietnamese-populated metropolitan area in the U.S.[21]. Limited studies in California have shown that Vietnamese older adults rate their health as poorer compared to their non-Hispanic White counterparts and also experience a higher prevalence of depressive symptoms [22,23]. A nationwide study [24] has found that Vietnamese-origin older adults have more Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL) disability than White, Black, Hispanic, and other Asian-origin older adults. Our VACS data found similar patterns with respect to their self-rated health, physical disability, and higher depressive symptoms, as well as high levels of loneliness [17].

The purpose of this analysis is to examine the association of ADL and IADL disability and chronic diseases with depressive symptoms in Vietnamese-origin older adults. We hypothesize that several strong relationships between ADL/IADL functional disability and chronic health conditions, and depressive symptoms would be found among Vietnamese-origin older adults in Houston, Texas.

2. Methods

2.1. Data and Sample

We used the Hispanic Established Populations for Epidemiological Studies of the Elderly (H-EPESE)[25] as a model and developed a cross-sectional health survey of Vietnamese-origin older adults who live in the Houston area. The survey was administered in 2017 and collected data on physical, mental, and cognitive health, disability, social support, use of social services, filial expectation from children, and religiosity from 131 older participants. In 2021, we developed VACS 2 and included additional instruments focused on cognitive function (e.g., Montreal Cognitive Assessment)[26,27], as well as COVID-19 related questions.

Inclusion criteria for both VACS 1 and 2 were self-identification as Vietnamese, ages 65 years and older, spoke English or Vietnamese and lived in the greater Houston, Texas area at the time of the survey. We excluded those who lived in long-term care facilities or were hospitalized. The final sample size was 208 Vietnamese-origin older adults (VACS 1: 131 and VACS 2: 77 older adults).

Data collection took place in November 2017 and April-May 2018 for VACS 1, and January-August 2021 for VACS 2. We distributed the study flyers in Vietnamese and English through Vietnamese social service agencies, senior centers, community centers, Vietnamese churches, temples, and adult day centers, and snowball sampling was widely used. A written consent form was obtained from all the participants prior to the survey. The study was approved by the University of Houston’s Institutional Review Board (VACS 1: STUDY00000419 and VACS 2: STUDY00002733). For more details on sampling and data collection, please see our previous manuscripts [16,17,18,19,20].

2.2. Measures

Depressive symptoms were measured with the Vietnamese version of the 20-item Center for Epidemiologic Studies Depression Scale (CES-D) [28,29]. Scores range from 0 to 60 with higher scores indicating greater depressive symptoms, and a score of 16 or greater indicating risk of clinical depression [30].

Functional disability was measured by Katz’s ADL [31] and Lawton and Brody’s IADL scale [32]. ADLs included bathing, dressing, toileting, transferring from a bed to a chair, walking across a small room, continence, and feeding. The ADL scale was scored whether the participant needed assistance to perform each activity (1 = yes or 0 = no) with higher scores indicating more disability (range from 0 to 7). The IADL scale requires more complex skills such as using the telephone, shopping, preparing food, housekeeping, laundry, using transportation, medication management, and managing finances. Items were scored if the study participant was able to perform each activity (0 = yes or 1 = no) (range from 0 to 9); higher scores suggest greater IADL disability.

Global Health was captured with a self-rated overall health (good/excellent vs fair/poor). Chronic diseases examined included arthritis, cancer, diabetes, heart problems, hypertension, liver disease, lung disease, and stroke. Respondents were asked if a doctor had ever told them they had each disease.

Sociodemographic characteristics included age, gender (female, male), marital status (married/partnered, not married/partnered), years of residence in the U.S., years of education, annual household income (<$25,000, $25,000-$50,000, >$50,000), living arrangement (live alone, live with others), and language spoken at home (Vietnamese, Vietnamese and other language).

2.3. Analyses

Descriptive statistics were used to characterize the sample stratified by depressive symptom status and sample. Sociodemographic variables included in regression analyses were identified based on a confound approach [33]. Variables significantly related to both the independent (ADL and IADL disability) and dependent (depression symptoms) variables were included in subsequent analyses. Arthritis and liver disease were identified as health conditions associated with depression (not shown in the table). For linear regression analyses, a combined variable of functional disability was created by summing ADL and IADL disabilities (range 0-16) to account for the high correlation (r = 0.57, p <0.001) between these variables, as well as expand range and sensitivity of the measurement [34,35]. A nested general linear model comparison was planned: The first model regressed depression on sociodemographics (marital status, gender), 2nd model added diseases (arthritis, liver disease), and the final model with the combined ADL/IADL disability. No multicollinearity was found in any combination of variables. Statistical analyses were conducted in R [36].

3. Results

Sample characteristics stratified by depression status are presented in Table 1. Depression was categorized based on a CES-D cutoff score of 16 [30]. The participants (N=208) were 56.2% female, on average 75.4 years old (age range 65-97), and 63% were married/partnered. All of them (100%) were born in Vietnam and had lived in the U.S. for an average of 25 years. They had completed an average of 8.2 years of education in Vietnam, and 90.4% reported low socioeconomic status (≤ $25K). The vast majority (80%) lived with their family members or relatives and spoke Vietnamese only (88%). Most rated their health as fair or poor (80%) and 76% of them reported at least one chronic disease. Compared to those with CES-D scores within normal ranges, those with elevated CES-D scores (16+) were more likely to be not married or not partnered (28.2% vs 50%, p = 0.002) and were more likely to report one or more chronic diseases (71.0% vs 83.3%, p = 0.041). Sample characteristics stratified by sample (Table 2) demonstrated that, compared to participants from VACS 2, VACS 1 participants lived in the U.S. longer (21.04 vs 26.70, p = 0.005) and reported less IADL difficulties (5.26 vs 4.28, p = 0.041).

Linear regression results predicting depressive symptoms as measured with the CES-D scores are shown in Table 3. When adjusting for other predictors in the final model, individuals with liver disease reported 7.90 [95% CI = 2.35, 13.45] higher CES-D points than those without. Older adults who reported more disability in combined ADLs and IADLs reported more depressive symptoms by 0.40 [95% CI = 0.12, 0.69] points on the CES-D for every additional ADL or IADL impairment. Marginal effects of predictors associated with CES-D total scores in the final model are presented in Figure 1.

4. Discussion

Using a combination of VACS 1 and 2 data, we examined the associations between chronic health conditions (i.e., 8 common chronic diseases), as well as functional disability (i.e., ADLs and IADLs), and depressive symptoms among 208 Vietnamese-origin older adults who lived in the greater Houston, Texas area. We found that having arthritis was positively associated with depressive symptoms in bivariate analysis. Minh Hoa et al.’s study (2003) (N = 2,119) found that 14.5% of Vietnamese adults in urban cities in Vietnam suffered musculoskeletal pain, and osteoarthritis was the most common disease. Mwangi and colleagues’ 2015 study [37], examining common chronic diseases in 2,873 Vietnamese older adults in rural Vietnam also showed arthritis/osteoarthritis was the most common chronic disease (35%). Several other studies on older adults in Vietnam have shown similar patterns of high prevalence of osteoarthritis, chronic pain, and its association with depressive symptoms [38,39]. Based on these previous studies, our finding of an association between arthritis and depressive symptoms is well aligned with the literature. Having arthritis and suffering from chronic pain certainly would make older adults uncomfortable and distressed in their daily lives.

In addition, liver disease showed an even stronger association with depressive symptoms, which was robust to adjustment from sociodemographic factors. Similar to arthritis, liver disease, hepatitis B and C specifically, is a common chronic disease among Asian Americans, and older Vietnamese have historically been disproportionally affected by the disease in Vietnam [40]. Other studies have found a high prevalence of Hepatitis B among Vietnamese Americans [41], and a high incidence of liver cancer among Vietnamese-origin men and women [42]. Liver disease is also common among Vietnamese men due to high alcohol consumption as Vietnam is one of the highest alcohol-consuming countries in the world [43]. Symptoms of liver disease (e.g., chronic fatigue, abdominal pain) could certainly predispose Vietnamese older adults to feeling weak and distressed. Among the ADLs examined, bathing and eating were the strongest correlates of depressive symptoms, and among IADLs, managing finances has the strongest effect (not shown in the table).

Previous studies have established a strong relationship between physical functional disability and depressive symptoms in community-dwelling older adults [5,6]. However, whether the relationships were with ADL or IADL functions varied. For example, among Asian Americans, Japanese, Korean, and Taiwanese older adults reported more depressive symptoms when they had high IADL difficulties [44,45,46] while Koreans in another study reported more depressive symptoms when their ADL disability was high [47]. A study of older Chinese Americans showed associations with both ADL and IADL disability and depressive symptoms [10]. Having limited control over their basic functioning would restrict Vietnamese older adults’ daily activities. IADL functions, however, can be culturally and socioeconomically biased, especially among women who often rely on family members for assistance with instrumental activities.

Limitations of this study should be noted. First, we used a small convenience sample collected only within the greater Houston area, and our results may not be generalizable to older Vietnamese in other parts of the country. The number of some chronic conditions including liver disease was small. Future studies with larger and more representative samples might provide a better picture of the population’s physical and emotional function. While most Vietnamese-origin older adults live with other family members and enjoy high levels of social support, healthcare professionals can help them to better access culturally and linguistically relevant services to help ameliorate their physical and emotional problems [48,49].