Abstract
Many studies have been conducted to investigate the effect of cultural influences on menopausal symptoms; however, associations between immigration transition and cognitive symptoms have rarely been uncovered. This secondary analysis aimed to determine these associations among 1,054 midlife women in the U.S. using the data from two national Internet surveys. The surveys included multiple questions on immigration transition, health and menopausal status, and the Cognitive Symptom Index for Midlife Women. The data analysis was performed using descriptive and inferential statistics including hierarchical multiple regression analyses. Non-immigrants had larger numbers and higher severity scores of total cognitive symptoms than immigrants (p<.001). Immigration status explained 1.28% of the total variances in the total numbers and 1.46% of the total variances in the total severity scores of total cognitive symptoms (p<.001). The study supported significant associations between immigration transition and cognitive symptoms of women at midlife.
Keywords: Cognition, Immigration, Middle Aged, Women, Race/Ethnicity
Menopause is a natural process that most midlife women inevitably experience (Rönnlund, Sundström, Adolfsson, & Nilsson, 2015; Sullivan Mitchell & Fugate Woods, 2001). About 60% of midlife women experience changes in their memory in the past few years (Sullivan Mitchell & Fugate Woods, 2001). Also, the Study of Women’s Health across the Nation (SWAN) indicated that peri-menopause was significantly correlated to forgetfulness (Gold, 2000). According to these studies, the prevalence rates of cognitive symptoms among midlife women were between 31 and 60%, depending on their menopausal status (Minarik, 2009; Vaari, Engblom, Helenius, Erkkola, & Polo-Kantola, 2008). Indeed, menopausal status has been considered as a major factor affecting women’s cognitive ability (B. McEwen, 2002; B. S. McEwen, 2001). It has been shown that menopausal transition leads to decreases in estrogen and other conditions that negatively affect women’s cognitive functions (B. McEwen, 2002; B. S. McEwen, 2001). McEwen postulated that decreases in estrogen could detrimentally affect the hippocampus and prefrontal cortex where estrogen receptors (responsible for episodic and working memory) are located (B. S. McEwen, 2001).
Although a number of studies have recently been carried out to determine the roles of cultural influences on menopausal symptoms (Melby, Lock, & Kaufert, 2005; Sievert, 2013; Sievert & Obermeyer, 2012), the associations between immigration transition and cognitive symptoms experienced during menopausal transition have rarely been determined. Furthermore, the findings of the few studies on the associations between immigration transition and cognitive symptoms tend to be inconsistent (Xu, Zhang, & Wu, 2017). Some of these studies have indicated that middle-aged immigrants tend to have poorer cognitive functions compared with non-immigrants (Plitas, Tucker, Kritikos, Walters, & Bardenhagen, 2009). On the contrary, others indicated better cognitive functions among immigrants (Hill, Angel, Balistreri, & Herrera, 2012) or no association between immigration transition and cognitive functions (Mejía, Miguel, Gutiérrez, Villa, & Ostrosky-Solis, 2006). This secondary analysis aims to determine the associations between immigration transition and cognitive symptoms experienced during the menopausal transition, using a relatively large sample of 1,054 midlife women in the U.S.
Associations of Immigration Transition to Cognitive Symptoms
Women often experience multiple changes in daily living, including languages and foods, during migration from a country to a different country (defined as immigration transition from here) (Y. Lee & Im, 2017). This immigration transition is naturally stressful; stress-related symptoms are often reported in this population (Chrousos, 2009; Chun, Organista, & Marin, 2003). Cognitive symptoms are known to be related to multiple factors, such as socioeconomic status, employment, job stress, multiple life roles, and general health (Greendale, Derby, & Maki, 2011; Wee et al., 2012). As women experience changes in these factors and subsequent stress during their immigration transition, it is possible that their cognitive functions are influenced by immigration transition in negative ways.
In this study, cognitive symptoms are broadly defined to incorporate possible racial/ethnic variances in cognitive symptoms that women could experience during their menopausal transition. Cognitive symptoms can be classified into three subtypes by cognitive functions—primary, secondary, and tertiary symptoms. Primary symptoms show clear alterations in cognitive functions (e.g., difficulties in concentration, forgetfulness). Secondary symptoms are strongly associated with alterations in cognitive functions (e.g., anxiousness, depression). Tertiary symptoms could possibly influence cognitive functions in a way (e.g., hot flashes and night sweats). In this study, menopausal transition is defined as the period of time between the beginning of variations in menstrual cycles and the last menstrual period (Greenblum, Rowe, Neff, & Greenblum, 2013). The menopausal status of the women was determined based on the definitions of menopausal stages by SWAN (see the Methods section).
The theoretical basis of this secondary analysis is acculturation theories explaining immigrants’ health (E.-O. Im & Yang, 2006). The acculturation theories are generally grouped into three categories: (a) “the positive effect of immigration on health,” (b) “the negative effect of immigration on health,” and (c) “acculturation as an outcome of immigration” (E.-O. Im & Yang, 2006). Theories supporting the positive effect of immigration on health assume that immigrants are selectively healthy, more resilient, and able to overcome the possible negative impact of immigration transition (Organista, Organista, & Kurasaki). According to these theories, immigrant midlife women would have less prevalent and less severe cognitive symptoms during their menopausal transition, which has actually been supported in some studies (Hill et al., 2012). The theories supporting the negative effect of immigration on health assume that immigration transition is inherently stressful and harmful to women’s health (Chun et al., 2003). According to these theories, immigrant midlife women would be more likely to have cognitive symptoms during their menopausal transition (Plitas et al., 2009). The third group of theories relate to acculturation has three subtypes: (a) “the single-continuum models”, (b) “two-culture matrix models”, and (c) “multidimensional models” (E.-O. Im, Ko, Chee, & Chee, 2017). According to the single-continuum models, the acculturation process is assumed to exist as a continuum between the unacculturated and the bi-culturated. According to the two-culture matrix models, immigrants are assumed to accept the new culture, while maintaining their own culture. Lastly, in the multidimensional models, acculturation process depends on individual characteristics. In other words, some immigrants tend to gain new characteristics from the host country more easily than others, and women’s selection of strategies for acculturation vary across different areas of their daily lives.
Purpose
The purpose of this study was to determine the associations between immigration transition and cognitive symptoms that midlife women experienced during their menopausal transition. The study had two aims: (a) to examine the differences in the total numbers and total severity scores of cognitive symptoms between immigrant and non-immigrant midlife women (by immigration status; Aim #1) and (b) to determine the associations of variables related to immigration transition (immigration status, years in the U.S., acculturation level, and racial/ethnic identity) to the total numbers and total severity scores of cognitive symptoms (Aim #2). The first aim is based on the aforementioned theories that support the associations between cognitive symptoms and immigration transition. The second aim is based on the acculturation theories, especially the multidimensional model subtype, as it supports multiple contextual factors that are linked to immigration transition.
Methods
The data from two national Internet survey studies among a total number of 1,054 midlife women in the U.S. (E.-O. Im et al., 2010; E.-O. Im et al., 2012) were used for this secondary analysis. The original studies included midlife women from four major racial/ethnic groups in the U.S. (Non-Hispanic (NH) White, Hispanic, NH African American, and NH Asian) and explored the differences in midlife women’s health issues/concerns by racial/ethnic identity. The Institutional Review Boards of the authors’ universities approved the studies. The original studies were conducted during the period of 2005 to 2013. All the participants gave their informed consent through the Internet. About 95~96% of the women who visited the project websites participated in the study.
Samples and Settings
The data from a total of 1,054 midlife women (316 Non-Hispanic [NH] Whites, 255 Hispanics, 250 NH African Americans, and 233 NH Asians) were used for this secondary analysis. Included were 1,054 midlife women who were 40 to 60 years old, who were literate (in English), who self-identified themselves as NH White, Hispanic, NH African American or NH Asian women, and who reported at least one cognitive symptom. All the participants were volunteers who reviewed the study announcements posted in Internet groups and visited the project websites. The studies were announced through contacting the gatekeepers of the Internet groups for midlife women that were searched using Google, Yahoo, MSN, and Bing. When the participants indicated their interests in participating in the studies through the project websites (by clicking “I agree to participate”), they were automatically screened against several questions to check if they met the inclusion criteria and quota requirements.
Because this was a secondary analysis, the sample size was pre-decided by the original studies. Using the G*Power 3.0 program, the required sample size was determined based on hierarchical multiple regression analyses (Aim #2). With 12 independent variables and an alpha level of .05 at 80% power, we assumed a small effect size of .02. The small effect size was chosen because the relationships between immigration transition and midlife women’s cognitive symptoms have rarely been studied. According to the power calculation, 878 women would be needed. Therefore, 1,054 women were sufficient enough to address the study aims.
Instruments
The original studies used multiple instruments, and this secondary analysis included only the data collected using questions on background characteristics, health and menopausal status, and immigration transition, and the Cognitive Symptom Index for Midlife Women (CMW).
Background characteristics and health and menopausal status.
Background characteristics and health and menopausal status of the participants were measured using eight items on background characteristics (e.g., age, education, family income, employment status) and nine items on health and menopausal status (e.g., weight, height, menstrual regularity and flow, last menstrual cycle). Based on the data collected using these questions, BMI was calculated and classified into four groups: “underweight (BMI<18.4),” “normal (18.5 to 24.9 kg/m2),” “overweight (25 to 29.9 kg/m2),” and “obese (≥30 kg/m2).” Menopausal status was decided based on the criteria used in the SWAN (Gold, 2000). Women having menses in the past three months without increased irregularity were considered as pre-menopausal. Women having menses in the past 12 months with increasing irregularity were regarded as peri-menopausal. Women without menses in the past 12 months (not related to pregnancy, medication, or severe weight loss) were considered as post-menopausal.
Immigration transition.
In this study, immigration transition refers to a transition from a country to a different country, and immigrants refer to those whose birth country is not the U.S., but migrated to the U.S. Because immigration transition is a multidimensional concept that cannot be easily operationalized (Avis et al., 2001), it is usually operationalized with proxy variables (Alvidrez, Azocar, & Miranda, 1996; Flaskerud, 2007). In this study, immigration transition was operationalized with four independent variables including immigration status, racial/ethnic identity, years in the U.S., and acculturation level. Immigration status was measured with a single question: “Were you born in the U.S.?” Then, immigration status was classified into two categories: immigrants and non-immigrants. The participants were also asked to identify their racial/ethnic identity using two questions. The first question was about ethnicity (Hispanic or Non-Hispanic [NH] by the NIH definition). The second question was about race (White, Black or African American, Asian American, Native Hawaiian, or other Pacific Islander by the NIH definition). Then, the participants were categorized into four major racial/ethnic groups: NH White, Hispanic, NH African American, and NH Asian American. The years in the U.S. were measured to identify the length of stay in the U.S. The acculturation level was decided by summing all five Likert-scale items (1= “exclusively own racial/ethnic group”; 5= “exclusively American”) in five areas (foods, music, customs, language, and close friends). These items were based on the Suinn-Lew Asian Self-Identity Acculturation Scale (Berkman & Ko, 2009). The reliability and validity of the items were established in midlife women from multiple racial/ethnic groups in a previous study (Suinn, Ahuna, & Khoo, 1992). In this study, Cronbach’s alpha of these items was 0.92. For data analyses, the acculturation level of those who were born in the U.S. was considered as five points (exclusively American), and their years in the U.S. were replaced with their age.
The Cognitive Symptom Index for Midlife Women (CMW).
The Cognitive Symptom Index for Midlife Women (CMW) was developed based on the Midlife Women’s Symptom Index (MSI) (E.-O. Im, 2006). The MSI is consisted of 71 questions on various symptoms (physical, psychological, and psychosomatic); only 20 questions related to cognitive functions are included in the CMW. These questions were decided based on a systematic literature review on cognitive functions related to menopausal transition (Bender et al., 2006; S. E. Lee, Diwan, & Yeo, 2010). As described above, the questions were about three major types of cognitive symptoms (primary, secondary, and tertiary symptoms). Eight items (tense or jumpy; easily excitable; forgettable; keyed up, jittery, or restless; difficulty in concentration; exhaustion or fatigue; worrying about body; and feeling clumsy) were categorized as primary symptoms. Nine items (feeling depressed; feeling unhappy; worrying; often crying; feeling anxious, tense or nervous; upset or irritated; feeling easily hurt; feeling grouchy; and mood swing) were categorized as secondary symptoms. Three items (sweats at night; hot flush; and difficulty in falling or staying asleep) were included as tertiary symptoms. Individual questions have two sub-questions: (a) a prevalence question (0 or 1; no or yes) and (b) a severity question (0~5; no symptom ~ extreme symptom). The total numbers of symptoms were calculated by totaling up all the items in the CMW (0 to 20). The total severity scores were also decided by summing up all the severity scores of individual questions in the CMW (0 to 100). Higher numbers and severity scores meant more frequent and serious symptoms. KR-20 of the CMW was .89 [the prevalence items], and Cronbach’s alpha of the CMW was .92 [the severity items]).
Data Analysis
First of all, the data analysis was conducted using descriptive statistics (e.g., frequencies, percentages, means, standard deviations) to examine the major variables. To identify the differences in cognitive symptoms by immigrant transition (to address Aim #1), the data were analyzed using chi-squared tests and t-tests. Hierarchical multiple regression analyses were used to identify the factors influencing the total numbers and total severity score of total cognitive symptoms (to address Aim #2). In the hierarchical multiple regression analyses, only the independents variables with the variables inflation factors (VIF) under 10 were included in order to avoid multicollinearity. Hierarchical multiple regression analyses were conducted as follows. First, immigration status was entered in the first step. Then, in the second step, years in the U.S., acculturation level, and racial/ethnic identity were included. Finally, the last step included background characteristics (e.g., education, family income, access to health care, social support), BMI, and menopausal status. Age was not included in the analyses since years in the U.S. were substituted by age for those who were born in the U.S.
Results
Background Characteristics and Health and Menopausal Status
Table 1 includes a summary of the participants’ characteristics. The participants included 316 non-Hispanic [NH] Whites (29.98%), 255 Hispanics (24.19%), 250 NH African Americans (23.72%), and 233 NH Asians (22.11%). Most of the participants were born in the U.S. (76.94%). The average age was 48.97 years old (SD = 5.69); the average years in the U.S. were 42.71 years (SD = 14.14); and the average acculturation level was 4.58 (on a 5-point scale, SD = 0.83). The majority of the participants were high school graduates (86.62%), employed (74.95%), married or partnered (67.74%), and had access to health care (86.62%). Most of the participants replied their family income was high (43.93%) and had adequate social support (32.16%). The mean BMI of the participants was 28.49 kg/m2 (SD = 7.37); 40.13% were “normal”, 25.10% were “overweight” (25.1%), and 34.72% were “obese.” About 40% were pre-menopausal, 33.11% were early/late peri-menopausal, and 27.23% were post-menopausal.
Table 1.
Background characteristics of the participants (N=1,054).
| Characteristics | n (%) |
|---|---|
| Racial/ethnic identity | |
| *NH White | 316 (29.98) |
| Hispanic | 255 (24.19) |
| NH African American | 250 (23.72) |
| NH Asian | 233 (22.11) |
| The country of birth | |
| Outside the U.S. | 243 (23.06) |
| U.S. | 811 (76.94) |
| Education | |
| ≤high school | 141 (13.38) |
| > high school | 913 (86.62) |
| Employment | |
| Yes | 790 (74.95) |
| No | 264 (25.05) |
| Marital Status | |
| Married/partnered | 714 (67.74) |
| Non-married/separated | 340 (32.26) |
| Access to health care | |
| Yes | 913 (86.62) |
| No | 141 (13.38) |
| Family Income | |
| Low | 185 (17.55) |
| Middle | 406 (38.52) |
| High | 463 (43.93) |
| **Social Support | |
| None | 171 (16.22) |
| A little | 270 (25.62) |
| Some | 274 (26.00) |
| Most | 339 (32.16) |
| BMI(kg/m2) | 28.49 ± 7.37 |
| Normal(<25) | 423 (40.13) |
| Overweight (25 to <30) | 265 (25.14) |
| Obese (≥ 30) | 366 (34.72) |
| Menopausal status | |
| Pre-menopause | 418 (39.66) |
| Early/late peri-menopause | 349 (33.11) |
| Post-menopause | 287 (27.23) |
NH=Non-Hispanic/
The availability of support from family members and friends
Differences in Cognitive Symptoms by Immigration Status
The differences in the total numbers and total severity scores of cognitive symptoms by immigration status are summarized in Table 2. Compared with immigrants, non-immigrants had larger numbers (t = 3.87, p < .001) and higher severity scores of total symptoms (t = 4.24, p < .001). Compared with immigrants, non-immigrants had larger numbers (t = 3.72, p < .001) and higher severity scores of primary symptoms (t = 3.86, p < .001). Compared with immigrants, non-immigrants had higher severity scores of secondary symptoms (t = 2.26, p < .05) and larger numbers (t = 7.10, p < .001) and higher severity scores of tertiary symptoms (t = 7.72, p < .001).
Table 2.
The differences in cognitive symptoms between immigrants and non-immigrants (N=1,054).
| Category | Total numbers of symptoms |
Total severity scores of symptoms |
||||||
|---|---|---|---|---|---|---|---|---|
| Non-Immigrants M±SD (n=811) | Immigrants M±SD (n=243) | t | p-value | Non-immigrants M±SD (n=811) | Immigrants M±SD (n=243) | t | p-value | |
| Primary symptoms | 2.86±2.20 | 2.28±2.02 | 3.720 | <.001 | 8.99±8.01 | 6.88±7.31 | 3.864 | <.001 |
| Secondary symptoms | 3.25±3.21 | 2.86±3.03 | 1.698 | .090 | 10.05±11.44 | 8.31±10.18 | 2.262 | .024 |
| Tertiary symptoms | 1.37±1.07 | 0.85±0.97 | 7.096 | <.001 | 4.59±4.14 | 2.60±3.32 | 7.717 | <.001 |
| Total | 7.47±5.60 | 5.99±5.14 | 3.871 | <.001 | 23.63±20.82 | 17.79±18.17 | 4.241 | <.001 |
The differences in individual cognitive symptoms by immigration status are summarized in Table 3. Compared with immigrants, non-immigrants reported more prevalent symptoms of “tense or jumpy (p < .05),” difficulty in concentration (p < .05),” “exhaustion or fatigue (p < .01),” “worrying about body (p < .001),” “feeling clumsy (p < .001),” “feeling grouchy (p < .05),” “mood swing (p < .05),” “sweats at night (p < .001),” “hot flush (p < .001),” and “difficulty in falling or staying asleep (p < .001).” Compared with immigrants, non-immigrants reported more severe symptoms of “tense or jumpy (p < .05),” keyed up, jittery, or restless (p < .05),” “difficulty in concentration (p < .05),” “exhaustion or fatigue (p < .01),” “worrying about body (p < .001),” “feeling clumsy (p < .001),” “often cry (p < .01),” “feeling grouchy (p < .05),” “mood swing (p < .01),” “sweats at night (p < .001),” “hot flush (p < .001),” and “difficulty in falling or staying asleep (p < .001).”
Table 3.
The differences in individual cognitive symptoms between immigrants and non-immigrants (N=1,054).
| Items | Prevalence |
Severity |
||||||
|---|---|---|---|---|---|---|---|---|
| Non-immigrants n (%) (n=811) | Immigrants n (%) (n=243) | X2 | p-value | Non-immigrants M±SD (n=811) | ImmigrantsM±SD (n=243) | t | p-value | |
| Primary Symptoms | ||||||||
| Tense or jumpy | 200(24.7) | 43(17.7) | 5.114 | .024* | 0.73±1.37 | 0.51±1.16 | 2.564 | .011* |
| Easily excitable | 174(21.5) | 56(23.0) | .277 | .599 | 0.63±1.28 | 0.66±1.32 | −.370 | .711 |
| Forgettable | 427(52.7) | 125(51.4) | .110 | .740 | 1.61±1.68 | 1.54±1.66 | .538 | .591 |
| Keyed up, jittery, or restless | 166(20.5) | 40(16.5) | 1.910 | .167 | 0.64±1.35 | 0.46±1.08 | 2.219 | .034* |
| Difficulty in concentration | 251(30.9) | 59(24.3) | 4.006 | .045* | 0.97±1.53 | 0.71±1.36 | 2.520 | .012* |
| Exhaustion or fatigue | 391(48.2) | 91(37.4) | 8.728 | .003* | 1.64±1.82 | 1.22±1.70 | 3.271 | .001* |
| Worrying about body | 465(57.3) | 105(43.2) | 15.026 | <.001* | 1.89±1.79 | 1.36±1.71 | 4.087 | <.001* |
| Feeling clumsy | 248(30.6) | 34(14.0) | 26.253 | <.001* | 0.89±1.45 | 0.41±1.09 | 5.530 | <.001* |
| Secondary Symptoms | ||||||||
| Feeling depressed | 270(33.3) | 76(31.3) | .345 | .557 | 1.08±1.64 | 0.94±1.49 | 1.262 | .208 |
| Feeling unhappy | 282(34.8) | 76(31.3) | 1.019 | .313 | 1.11±1.63 | 0.95±1.51 | 1.440 | .151 |
| Worrying | 284(35.0) | 82(33.7) | .134 | .715 | 1.14±1.66 | 0.98±1.48 | 1.388 | .166 |
| Often crying | 195(24.0) | 44(18.1) | 3.759 | .053 | 0.73±1.39 | 0.50±1.15 | 2.620 | .009* |
| Feeling anxious, tense or nervous | 312(38.5) | 86(35.4) | .755 | .385 | 1.18±1.62 | 1.05±1.52 | 1.178 | .239 |
| Upset or irritated | 329(40.6) | 95(39.1) | .169 | .681 | 1.25±1.63 | 1.10±1.50 | 1.367 | .172 |
| Feeling easily hurt | 317(39.1) | 85(35.0) | 1.337 | .247 | 1.16±1.57 | 1.00±1.46 | 1.490 | .137 |
| Feeling grouchy | 295(36.4) | 68(28.0) | 5.831 | .016* | 1.08±1.53 | 0.81±1.38 | 2.510 | .012* |
| Mood swing | 348(42.9) | 84(34.6) | 5.380 | .020* | 1.32±1.65 | 0.99±1.46 | 3.051 | .002* |
| Tertiary Symptoms | ||||||||
| Sweats at night | 251(30.9) | 36(14.8) | 24.565 | <.001* | 1.01±1.62 | 0.46±1.16 | 5.912 | <.001* |
| Hot flush | 402(49.6) | 70(28.8) | 32.584 | <.001* | 1.58±1.76 | 0.79±1.33 | 7.479 | <.001* |
| Difficulty in falling or staying asleep | 454(56.0) | 100(41.2) | 16.487 | <.001* | 2.00±1.92 | 1.35±1.74 | 4.964 | <.001* |
Statistically significant (p<.05).
Factors Associated with Cognitive Symptoms
Immigration status explained 1.28% of the total variances in the total numbers of total cognitive symptoms (p < .001; see Table 4). Years in the U.S., acculturation level, and racial/ethnic identity explained an additional 2.34% of the total variances in the total numbers of total symptoms (p < .001). Education, family income, marital status, access to health care, and social support explained an additional 7.99% of the total variances in the total numbers of total symptoms (p < .001). BMI and menopausal status of participants explained an additional 5.50% of the total variances in the total numbers of total symptoms (p < .001). In the final analytic model, racial/ethnic identity (being NH Asian & NH African Americans, p < .01), unemployment (p < .05), low family income (p < .01), middle family income (p < .01), no access to health care (p < .05), no social support (p < .01), little social support (p < .05), some social support (p < .05), obesity (p < .05), and early/late peri-menopausal status (p < .01) were significantly related to the total numbers of total symptoms.
Table 4.
Factors influencing the total numbers and total severity scores of total cognitive symptoms (N=1,054).
| Total numbers |
Total severity scores |
|||||||
|---|---|---|---|---|---|---|---|---|
| Step1 β | Step2a β | Step3b β | Step 4c β | Step1 β | Step2a β | Step3b β | Step 4c β | |
| Immigrant status | −.113** | −.009 | .003 | .005 | −.121** | .003 | .012 | .007 |
| Years in the U.S. | −.034 | .003 | −.004 | −.011 | .031 | .016 | ||
| Acculturation level | .017 | .008 | −.001 | .032 | .018 | .007 | ||
| Hispanic | −.047 | −.017 | −.025 | −.043 | −.006 | −.014 | ||
| ***NH Asian | −.227** | −.179** | −.159** | −.207** | −.155** | −.133** | ||
| ***NH African American | −.097** | −065 | −.071* | −.102** | −.064 | −.073* | ||
| Less than high school | .017 | .051 | .030 | .033 | ||||
| Unemployed | .079* | .067* | .101** | .088** | ||||
| Family income-low | .185** | .180** | .211** | .204** | ||||
| Family income-middle | .133** | .123** | .147** | .135** | ||||
| Non-married/separated | .006 | .004 | .005 | .001 | ||||
| No access to health care | −.068* | −.070* | −.064* | −.065* | ||||
| Social support-None | .124** | .123** | .129** | .128** | ||||
| Social support-A little | .101** | .089* | .102** | .090** | ||||
| Social support-Some | .09** | .079* | .072* | .061 | ||||
| Overweight | .040 | .036 | ||||||
| Obese | .086* | .100** | ||||||
| Early/late peri-menopausal | .194** | .173** | ||||||
| Post menopausal | −.057 | −.070* | ||||||
| R2 (%) | 1.28 | 3.92 | 11.91 | 17.41 | 1.46 | 3.82 | 13.27 | 18.43 |
| Δ R2 (%) | 2.34 | 7.99 | 5.50 | 2.37 | 9.45 | 5.16 | ||
| F(p) | 13.648 (<.001) | 7.111 (<.001) | 9.356 (<.001) | 11.469 (<.001) | 15.547 (<.001) | 6.939 (<.001) | 10.588 (<.001) | 12.296 (<.001) |
| Δ F(p) | 5.743 (<.001) | 10.466 (<.001) | 17.203 (<.001) | 5.156 (<.001) | 12.561 (<.001) | 16.354 (<.001) | ||
p<.05
p<.01
NH=Non-Hispanic
Controlled for years in the U.S., and acculturation level.
Controlled for years in the U.S., acculturation level, and self-reported racial/ethnic identity.
Controlled for years in the U.S., acculturation level, self-reported racial/ethnic identity, backgrounds characteristics, and health and menopausal status (education, employment, marital status, family income, access to health care, social support, BMI, and menopause status).
Immigration status explained 1.46% of the total variances in the total severity scores of total cognitive symptoms (p < .001). Years in the U.S., acculturation level, and racial/ethnic identity explained 2.37% of the total variances in the total severity scores of total symptoms (p < .001); education, family income, marital status, access to health care, and social support explained 9.45% of the total variances in the total severity scores of total symptoms (p < .001). BMI and menopausal status explained 5.16% of the total variances in the total severity scores of total symptoms (p < .001). In the final analytic model, racial/ethnic identity (being NH Asian & being NH African Americans; p < .01), unemployment (p < .01), low family income (p < .01), moderate family income (p < .01), no access to health care (p < .05), no social support (p < .01), little social support (p < .01), obesity (p < .01), early/late peri-menopausal (p < .01) status, and post-menopausal status (p < .05) were significantly related to the total severity scores of total symptoms.
Among all the variables related to immigration transition, only being NH Asian (ß=−.159, p<.01 for the total numbers; ß =−.135, p<.01 for the total severity scores) or NH African Americans (ß =−.101, p<.01 for the total numbers; ß =−.096, p<.01 for the total severity scores) were significant factors that influenced the total numbers and total severity scores of primary symptoms after controlling background characteristics and health and menopausal status. The variables related to immigration transition explained 3.96% of the total variances in the total numbers and 3.86 % of those in the total severity scores of primary symptoms (p < .001). Also, being NH Asian was the only factor that significantly influenced the total numbers (ß =−.094, p < .05) and total severity scores (ß =−.074, p < .05) of secondary symptoms after controlling background characteristics and health and menopausal status. The variables related to immigration transition explained 2.11% of the total variances in the total numbers and 2.12 % of those in the total severity scores of secondary symptoms (p < .001). Being Hispanic (ß =−.079, p<.05 for the total numbers; ß =−.220, p<.01 for the total severity scores) and being NH Asian (ß =−.074, p<.05 for the total numbers; ß =−.200, p<.01 for the total severity scores) were factors that significantly influenced the total numbers and total severity scores of tertiary symptoms after controlling background characteristics and health and menopausal status. The variables related to immigration transition explained 8.40% of the total variances in the total numbers and 7.77% of those in the total severity scores of tertiary symptoms (p < .001).
The significant factors related to total numbers and total severity scores of total symptoms were different by racial/ethnic group. In Hispanic and NH White women, immigrants who stayed longer in the U.S. and were more acculturated reported larger total numbers and higher total severity scores of total symptoms. Also, in Hispanic women, unemployment (β = .25), no access to health care (β = −.12) and some social support (β = .20) were significantly related to the total numbers of total symptoms (p < .05). In Hispanic women, unemployment (β = .28), some social support (β = .17), and being post-menopausal (β = .19) were significantly related to the total severity scores of total symptoms (p < .05). In NH White women, low educational level (β = .12), low (β = .35) and middle (β = .17) family income, no social support (β = .14), being overweight (β = .14) or obese (β = .12) and peri-menopausal status (β = −.12) and post-menopausal status (β = .14) were also significantly related to the total numbers of total symptoms (p < .05). Also, in NH White women, low educational level (β = .12), low (β = .32) and middle (β = .17) family income, low social support (β = .16), being overweight (β = .13), and peri-menopausal status (β = −.12) or post-menopausal status (β = .14) were significantly related to the total severity scores of total symptoms (p < .05).
On the contrary to Hispanic and NH White women, the immigration variables were not significantly associated with the total numbers or the total severity scores of total symptoms in NH African American and NH Asian women. Rather, in NH Asian women, low (β = .20) and middle (β = .18) family income, no support (β = .23), being obese (β = .20), and peri-menopausal status (β = .22) were significantly related to the total numbers of total symptoms (p < .05). Also, in NH Asian women, low (β = .20) and middle (β = .19) family income, no social support (β = .22), being obese (β = .23), and post-menopausal status (β = .18) were significantly related to the total severity scores of total symptoms (p < .05). In NH African American women, low family income (β = .20) and post-menopausal status (β = .15) were significantly related to the total severity scores of total symptoms (p < .05).
Discussion
The findings reported in this paper are consistent with the proposition by the theories on “positive effects of immigration on health.” According to these theories, immigrants should have smaller numbers and lower severe scores of cognitive symptoms. Indeed, in this study, immigrants reported smaller numbers and lower severity scores of cognitive symptoms compared with non-immigrants. Also, immigrants reported lower frequencies and lower severity scores of many individual cognitive symptoms. As supported in the theories on “positive effect of immigration on health,” immigrants would be naturally selected healthy people who tend to be healthier and more resilient (healthy immigrant effect) (Xu et al., 2017).
This study also supports that self-reported racial/ethnic identity would explain cognitive symptoms better than other variables related to immigration transition. When background characteristics were controlled, immigration status was a significant factor influencing the women’s cognitive symptoms, but the association of being NH Asian to cognitive symptoms was stronger than that of immigration status. Other non-significant variables related to immigration transition (years in the U.S., and acculturation level) might not adequately reflect the women’s immigration transition in multiple dimensions of their daily life that could possibly influence their cognitive symptoms. As racial/ethnic identity is reportedly associated with immigrants’ inner feelings on themselves (S. E. Lee et al., 2010), it could affect cognitive health more strongly compared with other variables related to immigration transition.
The findings on other factors influencing cognitive symptoms are also consistent with the literature. For instance, socioeconomic status is a frequently reported significant factor that affects cognitive symptoms (Bender et al., 2006; Greendale et al., 2011; Wee et al., 2012). Despite inconsistent findings on the directions of the associations between socioeconomic factors and cognitive symptoms in the literature, socioeconomic factors (e.g., education, physical labor, social support) are reportedly associated with cognitive impairments (Marengoni, Fratiglioni, Bandinelli, & Ferrucci, 2011). Moreover, health status and menopausal status have been reported to be significant factors that affect cognitive symptoms (Greendale et al., 2011). Yet, the findings on the specific significant factors influencing cognitive symptoms in each racial/ethnic group have rarely been reported in the literature, which makes this study unique.
In the interpretation of the study findings, yet, several limitations need to be considered. In this study, immigrants meant only the first and 1.5 generations of immigrants. Subsequently, the second and third generations of immigrants were not included, which limits the generalizability of the study findings. Despite the use of multidimensional questions related to the acculturation level, the multi-dimensionality of acculturation in diverse areas of daily life (Hill et al., 2012) might have not been adequately measured. Also, the women’s literacy level in English might have influenced the quality of data because the questions were administered only in English. Finally, the data totally depended on self-reports on cognitive symptoms. There were no validations on the self-reported data by clinicians.
The study supported significant associations of immigration transition to midlife women’s cognitive symptoms. The following suggestions are made for future research related to midlife women’s cognitive symptoms based on the findings reported in this paper. First of all, more studies are needed with diverse groups of racial/ethnic minority groups of midlife women in order to confirm the findings because there existed certain limitations in generalizability. Furthermore, for future research, a more comprehensive acculturation scale reflecting multi-dimensionality of acculturation needs to be used to produce more generalizable findings on the associations of immigration transition to cognitive symptoms. As discussed above, the five dimensions of questions on the acculturation level might not adequately reflect the multi-dimensionality of acculturation in midlife women’s daily life (Hill et al., 2012).
Acknowledgments
Source of Funding: This is a secondary analysis of the quantitative data from two lager studies that were funded by the National Institutes of Health (NIH/NINR/NIA, 1R01NR008926 and NIH/NINR/ NHLBI, R01NR010568).
Footnotes
Conflicts of Interest: The authors have no conflict of interest.
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