Lifetime occupational skill and later-life cognitive function among older adults in the United States, Mexico, India, and South Africa.

INTRODUCTION: We conducted a cross-national comparison of the association between main lifetime occupational skills and later-life cognitive function across four economically and socially distinct countries. METHODS: Data were from population-based studies of aging and their Harmonized Cognitive Assessment Protocols (HCAPs) in the US, South Africa, India, and Mexico (N = 10,037; Age range: 50 to 105 years; 2016 to 2020). Main lifetime occupational skill was classified according to the International Standard Classification of Occupations. Weighted, adjusted regression models estimated pooled and country-specific associations between main lifetime occupational skill and later-life general cognitive function in men and women. RESULTS: We observed positive gradients between occupational skill and later-life cognitive function for men and women in the US and Mexico, a positive gradient for women but not men in India, and no association for men or women in South Africa. DISCUSSION: Main lifetime occupations may be a source of later-life cognitive reserve, with cross-national heterogeneity in this association. HIGHLIGHTS: No studies have examined cross-national differences in the association of occupational skill with cognition. We used data from Harmonized Cognitive Assessment Protocols in the US, Mexico, India, and South Africa. The association of occupational skill with cognitive function varies by country and gender.

Determinants of retirement of formal and informal sector workers in Mexico: the role of health and economic security.

OBJECTIVE: We examine the socioeconomic and health drivers of retirement decisions and compare these determinants between formal and informal sector workers in Mexico. MATERIALS AND METHODS: Using data from the Mexican Health and Aging Study 2012 and 2015, we estimate conditional probit models of retirement using sociodemographic, health, health care utilization, health insurance, private pensions, and social security systems covariates. The Institutional Review Board at the University of Southern California reviewed and approved the research (IRB # UP-15-00023). RESULTS: We find that the social security systems are an important determinant for retirement age for formal sector workers. The informal sector workers, who lack access to retirement benefits of the social security system, make retirement decisions mainly based on health and access to health insurance through social security. CONCLUSION: Despite the lack of access to social security benefits, informal sector workers do not respond strongly to socioeconomic factors in determining the timing of retirement. Strengthening access to better health care services could improve health, extend working lives, and promote healthy aging for workers in the informal sector.

Rural and urban differences in lifetime occupation and its influence on mortality among Mexican adults.

OBJECTIVE: To determine how primary lifetime occupation type is associated with mortality, and how the relationship varies by rural and urban dwelling. MATERIALS AND METHODS: Data come from 2001-2018 Mexican Health and Aging Study (adults aged 50+, n=11 094). We created five occupation categories. Cox proportional hazard models predicted mortality using baseline covariates. RESULTS: In both rural and urban settings, participants with manual jobs, such as agriculture and production/industrial jobs, had an increased risk of mortality compared to those with administrative/professional jobs. In urban settings, participants in the domestic/service and no main job categories had higher risk of mortality than those in the administrative/professional category. For men these differences remained, but not for women. CONCLUSION: In a context of rural and urban demographic shifts, it is crucial to consider the implications that occupation as a socioeconomic factor can have on health and to identify the most vulnerable groups.

Cognitive life expectancy by educational attainment in Mexican adults aged 60 and older.

OBJECTIVE: To estimate cognitively healthy life expectancy (CHLE), cognitive impairment life expectancy (CILE), and dementia life expectancy (DLE) in Mexican adults aged 60 and older stratified by educational attainment. MATERIALS AND METHODS: The data were obtained from Waves 1 (2001) to 5 (2018) of the Mexican Health and Aging Study. The life expectancy was estimated using a multistate life table analysis. RESULTS: CHLE at age 60 increased with higher educational attainment and ranged from 17.9 to 24.4 years in female participants, and 17.2 to 21.3 in male participants. The CILE and DLE decreased with greater educational attainment. The CILE ranged from 0.7 to 2.8 years in female participants and 0.7 to 2.6 in male participants. CONCLUSIONS: Older adults in Mexico with higher education live more years with good cognitive health and fewer years with cognitive impairment and dementia. Education has a stronger effect on the length of cognitively healthy life expectancies than on total life expectancies.

20 years of the Mexican Health and Aging Study.

The Mexican Health and Aging Study (MHAS) is a longitudinal study using a national sample of approximately 15,000 community-dwelling adults aged 50 years old and older in Mexico. Spanning over 20 years (2001-2021), six waves of data collection establish the MHAS as the leading data platform for the study of aging in Latin America.

The impact of insomnia symptoms on obesity among Mexicans aged 50 and older.

OBJECTIVE: To examine the association between insomnia and obesity in Mexican adults aged 50 and older. MATERIALS AND METHODS: We used data from the Mexican Health and Aging Study (2015-2018). Self-reported insomnia was measured using the modified insomnia severity index with scores ranging from zero to six. Obesity was categorized using body mass index (BMI ≥ 30 kg/m2). We used generalized estimating equations to assess the association between insomnia and obesity over three years. RESULTS: Insomnia was associated with obesity (odds ratio [OR]: 1.06, 95% confidence interval [CI]: 1.01,1.11), among those with no obesity at baseline. Among those with obesity, insomnia was not associated with changes in BMI. Lastly, obesity was not associated with changes in insomnia symptoms. CONCLUSION: This work highlights the association between insomnia and obesity among older Mexican adults and demonstrates the importance of further studies on the effects of insomnia within this population.

Assigning lifetime occupation domains for older Mexicans: MHAS-O*NET linkage protocol.

OBJECTIVE: We developed a MHAS (Mexican Health and Aging Study) and O*NET (Occupational Information Network) linkage to allow global researchers using MHAS data to assign lifetime occupation domains for older Mexicans. MATERIALS AND METHODS: Three bilingual raters independently matched 440 records with 132 unique occupation codes from the 2012 MHAS. We used a modified Delphi technique to reach agreements. To assess reliability, we compared the distribution of observations between the MHAS file and the MHAS-O*NET linked file across five job categories (upper white collar, lower white collar, upper blue collar, low blue collar, and agriculture/fishing/forestry). The Institutional Review Board at the University of Texas Medical Branch reviewed and approved the research (IRB # 21-0268). RESULTS: Using the developed 1:1 MHAS-ONET linkage, consistency between MHAS and ONET was 97.4% across the five job categories. CONCLUSION: This MHAS-O*NET linkage will allow researchers to analyze the association between lifetime occupation and multiple dimensions of health, functionality, and retirement determinants for a low-middle income country with a large proportion of workers in the informal sector.

Midlife Vascular Factors and Prevalence of Mild Cognitive Impairment in Late-Life in Mexico.

OBJECTIVE: To estimate the prevalence of mild cognitive impairment (MCI) and its subtypes and investigate the impact of midlife cardiovascular risk factors on late-life MCI among the aging Mexican population. METHOD: Analyses included a sample of non-demented adults over the age of 55 living in both urban and rural areas of Mexico (N = 1807). MCI diagnosis was assigned based on a comprehensive cognitive assessment assessing the domains of memory, executive functioning, language, and visuospatial ability. The normative sample was selected by means of the robust norms approach. Cognitive impairment was defined by a 1.5-SD cut-off per cognitive domain using normative corrections for age, years of education, and sex. Risk factors included age, education, sex, rurality, depression, insurance status, workforce status, hypertension, diabetes, stroke, and heart disease. RESULTS: The prevalence of amnestic MCI was 5.9%. Other MCI subtypes ranged from 4.2% to 7.7%. MCI with and without memory impairment was associated with older age (OR = 1.01 [1.01, 1.05]; OR = 1.03 [1.01, 1.04], respectively) and residing in rural areas (OR = 1.49 [1.08, 2.06]; OR = 1.35 [1.03, 1.77], respectively). Depression (OR = 1.07 [1.02, 1.12]), diabetes (OR = 1.37 [1.03, 1.82]), and years of education (OR = 0.94 [0.91, 0.97]) were associated with MCI without memory impairment. Midlife CVD increased the odds of MCI in late-life (OR = 1.76 [1.19, 2.59], which was driven by both midlife hypertension and diabetes (OR = 1.70 [1.18, 2.44]; OR = 1.88 [1.19, 2.97], respectively). CONCLUSIONS: Older age, depression, low education, rurality, and midlife hypertension and diabetes were associated with higher risk of late-life MCI among older adults in Mexico. Our findings suggest that the causes of cognitive impairment are multifactorial and vary by MCI subtype.

The pain and depressive symptoms cascade: A bidirectional analysis of the Mexican Health and Aging Study 2012-2015.

OBJECTIVES: The association of pain and depression has not been evaluated in low- and middle-income countries, which have a disproportionate burden of pain compared to high-income countries. METHODS: Using data from the Mexican Health and Aging Study (baseline, 2012; follow-up, 2015), we examined the bidirectional relationship between pain and depressive symptoms and identified shared predictors among community-dwelling participants ≥60 years (n = 7237). Multivariable logistic regressions models evaluated the association between (1) baseline pain and incident elevated depressive symptoms and (2) baseline depressive symptoms and incident pain, adjusting for demographic, socioeconomic, and health-related factors. Models included inverse probability weights and evaluated interactions by gender. RESULTS: Participants (55.0% women) were on average 69.1 years old. Over half reported no pain (60.7%) and low/no depressive symptoms (67.9%) in 2012, of which, 20.2% reported elevated depressive symptoms and 25.3% self-reported pain in 2015. Baseline pain was associated with higher odds of incident elevated depressive symptoms (aOR 1.65; 95% CI, 1.41-1.93). Baseline elevated depressive symptoms were associated with higher odds of developing pain (aOR 1.57; 95% CI, 1.32-1.87). Age, gender, self-rated health, and activity of daily living limitations were shared risk factors for pain and elevated depressive symptomatology onset. Although the incidence of elevated depressive symptoms and pain was higher in women, there were no statistically significant interactions. CONCLUSIONS: Older adults with pain or depression may be at risk for developing the other. These shared predictors could help identify patients in clinical settings, where pain and depression are often overlooked, reducing the cascading risk of this comorbidity.

Quantifying Lifecourse Drivers of International Migration: A Cross-national Analysis of Mexico and the United States.

BACKGROUND: Evaluating the long-term health consequences of migration requires longitudinal data on migrants and non-migrants to facilitate adjustment for time-varying confounder-mediators of the effect of migration on health. METHODS: We merged harmonized data on subjects aged 50+ from the US-based Health and Retirement Study (HRS) and the Mexican Health and Aging Study (MHAS). Our exposed group includes MHAS-return migrants (n = 1555) and HRS Mexican-born migrants (n = 924). Our unexposed group includes MHAS-never migrants (n = 16,954). We constructed a lifecourse data set from birth (age 0) until either age at migration to the United States or age at study entry. To account for confounding via inverse probability of treatment weights (IPTW), we modeled the probability of migration at each year of life using time-varying pre-migration characteristics. We then evaluated the effect of migration on mortality hazard estimated with and without IPTW. RESULTS: Mexico to the United States migration was predicted by time-varying factors that occurred before migration. Using measured covariates at time of enrollment to account for selective migration, we estimated that, for women, migrating reduces mortality risk by 13%, although this estimate was imprecise and results were compatible with either large protective or deleterious associations (hazard ratio [HR] =0.87, 95% confidence interval [CI]: 0.60, 1.27). When instead using IPTWs, the estimated effect on mortality was similarly imprecise (HR = 0.98, 95% CI: 0.77, 1.25). The relationship among men was similarly uncertain in both models. CONCLUSIONS: Although time-varying social factors predicted migration, IPTW weighting did not affect our estimates. Larger samples are needed to precisely estimate the health effects of migration.

Associations between spousal caregiving and health among older adults in Mexico: A targeted estimation approach.

OBJECTIVE: To evaluate associations between spousal caregiving and mental and physical health among older adults in Mexico. METHODS: Data come from the Mexican Health & Aging Study, a national population-based study of adults ≥50 years and their spouses (2001-2015). We compared outcomes for spousal caregivers to outcomes for those whose spouses had difficulty with at least one basic or instrumental activity of daily living (I/ADL) but were not providing care; the control group conventionally includes all married respondents regardless of spouse's need for care. We used targeted maximum likelihood estimation to evaluate the associations with past-week depressive symptoms, lower-body functional limitations, and chronic health conditions. RESULTS: At baseline, 846 women and 629 men had a spouse with ≥1 I/ADL. Of these, 60.9% of women and 52.6% of men were spousal caregivers. Spousal caregiving was associated with more past-week depressive symptoms for men (Marginal Risk Difference (RD): 0.27, 95% confidence internal [CI]: 0.03, 0.51) and women (RD: 0.15, 95% CI: 0.07, 0.23). We could not draw conclusions about associations with lower-body functional limitations and chronic health conditions. On average, all respondents whose spouses had caregiving needs had poorer health than the overall sample. CONCLUSION: We found evidence of an association between spousal caregiving and mental health among older Mexican adults with spouses who had need for care. However, our findings suggest that older adults who are both currently providing or at risk of providing spousal care may need targeted programs and policies to support health and long-term care needs.

Family help received by Mexican older adults across socioeconomic strata: changes over a critical decade.

OBJECTIVE: To identify how patterns of family economic support help alleviate the cumulative effects of inequality, with focus on the financial support that children give their elderly parents. METHODS: This paper uses data from two cross-sections, 2001 and 2012, of the Mexican Health and Aging Study for the 50 years and older population. Analysis includes descriptive statistics to estimate differences in economic support based on family and individual characteristics; and a multinomial probit regression model, in each cross-section, to analyze the amount of money received for economic help and the associated characteristics. RESULTS: Economic help received was significantly reduced, both in proportion, from 20% to 10% between 2001 and 2012, and in the amount received, with differences by income quintile. In 2001, 14.9% of those in the lowest quintile (Q1) would move to Q4-Q5 with children's help; in 2012, this was 9.1%. The adjusted probability of receiving any amount of money from children decreased from 0.511 in 2001 to 0.340 in 2012. CONCLUSIONS: In Mexico, economic inequality in the 50 years and older population remains a constant. Economic help received from children varied by income quintile and plays an important role for those in the lowest income groups. More research is needed to understand the patterns of intergenerational exchanges as these cohorts of older adults continue to age and as future cohorts are entering old age with more pronounced changes than the current cohorts experienced over this critical decade.

US Migration Status of Adult Children and Cognitive Decline Among Older Parents Who Remain in Mexico.

Low- and middle-income countries (LMICs) are experiencing rapid aging, a growing dementia burden, and relatively high rates of out-migration among working-age adults. Family member migration status may be a unique societal determinant of cognitive aging in LMIC settings. We aimed to evaluate the association between adult child US migration status and change in cognitive performance scores using data from the Mexican Health and Aging Study, a population-based, national-level cohort study of Mexico adults aged ≥50 years at baseline (2001), with 2-, 12-, and 14-year follow-up waves (2003, 2012, and 2015). Cognitive performance assessments were completed by 5,972 and 4,939 respondents at 11 years and 14 years of follow-up, respectively. For women, having an adult child in the United States was associated with steeper decline in verbal memory scores (e.g., for 9-year change in immediate verbal recall z score, marginal risk difference (RD) = -0.09 (95% confidence interval (CI): -0.16, -0.03); for delayed verbal recall z score, RD = -0.10 (95% CI: -0.17, -0.03)) and overall cognitive performance (for overall cognitive performance z score, RD = -0.04, 95% CI: -0.07, -0.00). There were mostly null associations for men. To our knowledge, this is the first study to have evaluated the association between family member migration status and cognitive decline; future work should be extended to other LMICs facing population aging.

Having an Adult Child in the United States, Physical Functioning, and Unmet Needs for Care Among Older Mexican Adults.

BACKGROUND: Migration of adult children may impact the health of aging parents who remain in low- and middle-income countries. Prior studies have uncovered mixed associations between adult child migration status and physical functioning of older parents; none to our knowledge has examined the impact on unmet caregiving needs. METHODS: Data come from a population-based study of Mexican adults ≥50 years. We used longitudinal targeted maximum likelihood estimation to estimate associations between having an adult child US migrant and lower-body functional limitations, and both needs and unmet needs for assistance with basic or instrumental activities of daily living (ADLs/IADLs) for 11,806 respondents surveyed over an 11-year period. RESULTS: For women, having an adult child US migrant at baseline and 2-year follow-up was associated with fewer lower-body functional limitations [marginal risk difference (RD) = -0.14, 95% confidence interval (CI) = -0.26, -0.01] and ADLs/IADLs (RD = -0.08, 95% CI = -0.16, -0.001) at 2-year follow-up. Having an adult child US migrant at all waves was associated with a higher prevalence of functional limitations at 11-year follow-up (RD = 0.04, 95% CI = 0.01, 0.06). Having an adult child US migrant was associated with a higher prevalence of unmet needs for assistance at 2 (RD = 0.13, 95% CI = 0.04, 0.21) and 11-year follow-up for women (RD = 0.07, 95% CI = -0.02, 0.15) and 11-year follow-up for men (RD = 0.08, 95% CI = 0.00, 0.16). CONCLUSION: Having an adult child US migrant had mixed associations with physical functioning, but substantial adverse associations with unmet caregiving needs for a cohort of older adults in Mexico.

The effect of educational attainment on cognition of older adults: results from the Mexican Health and Aging Study 2001 and 2012.

Objective: This paper seeks to document changes in the effect of educational attainment on cognitive function of older adults in Mexico, and measure gender differences using data from two time periods. Methods: The data come from the Mexican Health and Aging Study (MHAS), taking the cross-sections of adults aged 60 years or older interviewed in 2001 and 2012. We perform an OLS regression using standardized z-scores for five individual cognitive domains and for total cognition. Results: Total cognitive scores and educational attainment were higher for men than women in both years. When cognitive components were analyzed separately, women had higher verbal memory and verbal recall scores than men. The gender gap in overall cognition score was smaller in 2012 compared to 2001, while the gender gap in educational attainment was larger in 2012 than in 2001. Even though men had higher educational attainment than women, the effect of educational attainment on cognition was higher for women. Similarly, the difference between total scores for each task for men compared to women decreased between 2012 and 2001, except for verbal learning and verbal recall where the gender difference widened. Conclusions: If younger cohorts of women continue to progressively achieve higher levels of education, the gender gap in old-age cognition should close. Additional work should determine the mechanisms through which added formal education seems to translate into higher cognitive gains for women compared to men.

Chronic comorbidities and cervical cancer screening and adherence among US-born and foreign-born women.

PURPOSE: Whereas chronic conditions and foreign-birth have an inverse relationship with cervical cancer screening, the combined effect of these factors on screening is unknown. This study examined the associations between chronic comorbidities and Pap screening recommendations and adherence, and whether these associations vary between foreign- and US-born women. METHODS: In 2017, data from 2013 and 2015 National Health Interview Survey on women aged 21-65 years (N = 20,080) were analyzed. Bivariate associations between chronic comorbidities (hypertension, diabetes, and obesity) and cervical cancer screening recommendation and adherence (screened in the last 3 years) were examined using Chi-square analysis. Multivariate binary logistic regression was used to examine the association between foreign-born status and participant Pap test adherence, adjusting for physician Pap test recommendation and chronic comorbidities. RESULTS: Obesity, hypertension, and diabetes were positively associated with Pap screening recommendation. Hypertension and diabetes were negatively associated with screening adherence. Pap screening recommendation (60% vs. 57%, p < 0.05) and adherence (85% vs. 78%, p < 0.001) were higher among foreign-born than US-born women. After adjusting for chronic conditions, foreign-born women had significantly lower odds of receiving Pap tests compared with US-born women (OR 0.8, 95% CI 0.6-0.9). In stratified analysis, only obesity was associated with Pap testing among US-born and foreign-born women. Among foreign-born women, the association between obesity and Pap testing was attenuated after controlling for years lived in the US and citizenship. CONCLUSION: Public health intervention efforts must improve regular access to preventive care and encourage Pap screening among women diagnosed with chronic conditions. Future research should further identify additional factors driving the cervical cancer screening practices of both US- and foreign-born women with and without chronic conditions.

Cross-national health comparisons using the Rasch model: findings from the 2012 US Health and Retirement Study and the 2012 Mexican Health and Aging Study.

PURPOSE: Cross-national comparisons of patterns of population aging have emerged as comparable national micro-data have become available. This study creates a metric using Rasch analysis and determines the health of American and Mexican older adult populations. METHODS: Secondary data analysis using representative samples aged 50 and older from 2012 U.S. Health and Retirement Study (n = 20,554); 2012 Mexican Health and Aging Study (n = 14,448). We developed a function measurement scale using Rasch analysis of 22 daily tasks and physical function questions. We tested psychometrics of the scale including factor analysis, fit statistics, internal consistency, and item difficulty. We investigated differences in function using multiple linear regression controlling for demographics. Lastly, we conducted subgroup analyses for chronic conditions. RESULTS: The created common metric demonstrated a unidimensional structure with good item fit, an acceptable precision (person reliability = 0.78), and an item difficulty hierarchy. The American adults appeared less functional than adults in Mexico (ß = - 0.26, p < 0.0001) and across two chronic conditions (arthritis, ß = - 0.36; lung problems, ß = - 0.62; all p < 0.05). However, American adults with stroke were more functional than Mexican adults (ß = 0.46, p = 0.047). CONCLUSIONS: The Rasch model indicates that Mexican adults were more functional than Americans at the population level and across two chronic conditions (arthritis and lung problems). Future studies would need to elucidate other factors affecting the function differences between the two countries.

Health Insurance and the Aging: Evidence From the Seguro Popular Program in Mexico.

Aimed at covering the large fraction of workers in the informal sector without access to a social security program, the Mexican public health insurance program Seguro Popular began in 2002 and now reaches more than 50 million individuals. We estimate impacts of Seguro Popular for the population aged 50 and older on a set of indicators related to health care including utilization, diagnostic/preventive tests, and treatment conditional on being ill. Using the longitudinal Mexican Health and Aging Study over the period 2001-2012, we conduct before and after difference-in-difference matching impact estimators. Our results suggest large and important effects of the Program on utilization and diagnostic tests. We find overall smaller effects on the probability of being in treatment for individuals with chronic diseases, but these effects are concentrated in rural areas with relatively more health services versus rural areas with lower levels of health services. These results suggest that, to the extent that health services become more available in rural areas lacking services, effects of health insurance may increase.

The effect of adult children living in the United States on the likelihood of cognitive impairment for older parents living in Mexico.

OBJECTIVE: The increased risk for poor physical and mental health outcomes for older parents in Mexico who have an adult child living in the United States may contribute to an increased risk for cognitive impairment in this population. The objective of this study was to examine if older adults in Mexico who have one or more adult children living in the United States are more or less likely to develop cognitive impairment over an 11-year period compared to older adults who do not have any adult children living in the United States. DESIGN: Data for this study came from Wave I (2001) and Wave III (2012) of the Mexican Health and Aging Study. The final sample included 2609 participants aged 60 and over who were not cognitively impaired in 2001 and had one or more adult children (age ≥15). Participants were matched using a propensity score that was estimated with a multivariable logistic regression model that included sociodemographic characteristics and migration history of the older parents. RESULTS: Having one or more adult children living in the United States is associated with lower socioeconomic status and higher number of depressive symptoms, but greater social engagement for older parents living in Mexico. No significant differences in the odds for developing cognitive impairment according to having one or more adult children living in the United States were detected. CONCLUSION: In summary, having one or more adult children living in the United States was associated with characteristics that may increase and decrease the risk for cognitive impairment. This may contribute to the non-significant relationship between migration status of adult children and likelihood for cognitive impairment for older parents living in Mexico.

Falls in Mexican older adults aged 60 years and older.

BACKGROUND: Falls are a major cause of disability, morbidity, institutionalization, and mortality in older adults. OBJECTIVES: The purpose of the study was to examine the risk factors for falls among Mexican older adults aged 60 years and older. METHODS: This study included 6247 participants and their spouse or partner aged 60 years and older from the Mexican Health and Aging Study, an ongoing longitudinal study (2001-2012) conducted in Mexico. Measures included socio-demographics, falls, physical activity, comorbid conditions, pain, vertigo, vision and hearing impairments, urinary incontinence, lower extremity functional limitation, activities of daily living (ADLs), cognitive function, and depressive symptoms. RESULTS: Mean age was 69.6 years (standard error = 0.18) and 51.8% were female. Forty percent reported one or more falls at baseline. Older age, being female, obesity, arthritis, fractures, stroke, suffering pain, vertigo, lower extremity functional limitations, physical activity, depressive symptoms, urinary incontinence, and ADL disability were significant factors associated with one or more falls over time. DISCUSSION: Early detection and treatment of the risk factors for falls in this population will help improve the quality of life and reduce medical complications and health care costs.