Validity of Self-rated Health among Latino(a)s
Brian Karl Finch1,
Robert A. Hummer2,
Maureen Reindl2 and
William A. Vega3
1 School of Public Health, University of California at Berkeley, Berkeley, CA.
2 Population Research Center and Department of Sociology, University of Texas at Austin, Austin, TX.
3 Department of Psychiatry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, NJ.
 |
ABSTRACT
|
---|
The authors investigated whether self-rated health (SRH) had differential mortality risks for Latino(a) adults of various acculturation statuses living in the United States. They used cumulative National Health Interview Survey data from 1989 to 1994 (n = 37,713) linked with the National Health Interview Survey Multiple Cause of Death data files (1,364 deaths) that match records from the National Death Index through 1997. The authors specified survival models to estimate the effect of SRH on mortality and further stratified their model by birth and duration in the United States as proxies for acculturation. These estimates were compared across strata. Poor SRH was found to be a weaker predictor of subsequent mortality risk among the less acculturated, although the overall risk among the aggregated sample is similar to the risk reported in previous studies. The relation between poor SRH and mortality risk increases with United States acculturation among Latinos. While poor SRH was significantly associated with short-term mortality among the least acculturated, this association did not persist beyond 2-year mortality risk. Health researchers wishing to use SRH to assess the physical health of multiethnic populations should at least control for levels of acculturation among respondents.
acculturation; emigration and immigration; health status; health surveys; mortality
Abbreviations:
NHIS, National Health Interview Survey; SRH, self-rated health
 |
INTRODUCTION
|
---|
The validity of self-rated health (SRH) measures, in terms of their predictive import for mortality risk, has been established in multiple studies. A well-cited review concludes that SRH is an independent predictor of mortality, above and beyond physician assessments of health (1
). Global SRH measures generally include a question such as "How would you rate your overall health?" and offer five response categories that range from excellent to poor. SRH measures are often dichotomized as fair/poor versus all other categories since the poor/fair categories represent expressions of health distress and/or the presence of disease; a rating of fair/poor also represents a heightened mortality risk.
Responses to SRH may vary depending on the race/ethnicity of the person being interviewed, however. For example, Latinos may somatize their emotional/mental health into physical health constructs (2
) such as SRH. Somatization in this regard is defined as the tendency to present health complaints that are indicative of personal or social problems. Because of this tendency, Latino immigrants rate themselves in poorer health than do native-born Latinos; several studies have confirmed this result (3
5
).
This finding is a troubling anomaly amidst burgeoning evidence of an inverse relation between acculturation and health (5
). Numerous studies have demonstrated that higher levels of acculturation among immigrant Latinos are positively related to the following health outcomes: adult mortality (6


10
), psychiatric disorders (11
, 12
), infant mortality (13
), psychologic distress (14
), deleterious health behaviors (15
), substance use (16
), low birth weight (17
, 18
), and risk for several nonfatal morbidities (19
). Therefore, what should we make of the apparent anomalous relation between SRH and acculturation? After all, a growing Latino population in the United States, largely due to increased immigration, has important implications for the ability of health researchers to quickly and easily compare the health status of multiethnic populations in the United States through the use of SRH questions.
Following McGee et al. (20
), we sought to assess the validity of SRH for mortality risk by using a sample of Latino adults who were characterized as having different levels of acculturation to US society. Our primary research question was, "Are subsequent mortality risks among Latinos who rate themselves in fair/poor health moderated by levels of acculturation?"
 |
MATERIALS AND METHODS
|
---|
Data set
We utilized a unique data set that aggregates multiple years (19891994) of the National Health Interview Survey (NHIS) (21
) and is linked to the NHIS: Multiple Cause of Death (22
) data set for 19891997. Adult respondents in each year of the NHIS were searched for in the National Death Index and matched according to a complex scoring algorithm. Potential matches were classified according to the strength of the match, and we utilize the match that is recommended by National Center for Health Statistics and has been estimated to classify more than 97 percent of the subjects correctly.
We selected only the subsample of respondents who self-identified as Latino/Hispanic from each year of the NHIS; 75 percent of respondents live in California, Texas, New York, Florida, Illinois, Arizona, and New Jersey. Although we excluded those for whom a self-rating of health is missing (n = 160), we utilized dummy variables for each covariate that controlled for missing data to minimize nonresponse bias. Our final sample size included 37,713 Latino adults who were age 18 years or older at the time of the survey between 1989 and 1994. Of the Latino respondents to the NHIS between these years, 1,364 (3.6 percent) had died as of the 1997 matching with the National Death Index.
Measures
Our key predictor variable was SRH, and our key interest was in the estimated magnitude of this variable on mortality risk across respondents of varying acculturation status. We treated SRH as a dichotomous measure, distinguishing between those who rate themselves in fair/poor health versus all others (excellent/very good/good). Since the language of the survey was not available, we used a proxy for acculturation from duration of stay in the United States; this variable was categorized into three strata, including 1) recent immigrant, less than 10 years in the United States (n = 7,327; 156 deaths); 2) long-term immigrant, 10 years or more in the United States (n = 12,738; 564 deaths); and 3) born in the United States (n = 17,648; 644 deaths). We also included dummy variables for national origin, comprising Mexican Americans, Puerto Ricans, Cubans, Central/South Americans, and other Latinos.
Other demographic variables included age, sex, and marital status. Socioeconomic controls included education, annual family income, and employment status. Since these variables came from a cross-sectional survey, they were measured at the time of the baseline survey only and were time invariant.
Methodology
We first used weighted Cox proportional hazards models (23
) to estimate the effects of SRH on mortality risk. Our modeling strategy was to look first at the overall risk of mortality by SRH status among our entire Latino sample and then to stratify this relation according to birth/duration in the United States. We also estimated piecewise constant hazard models (23
), which served two purposes. First, piecewise constants allowed us to account better for heterogeneity of hazards over time (i.e., nonproportionality), and second, piecewise constant models allowed us to determine whether SRH ratings had a short- or long-term predictive value for mortality risk.
 |
RESULTS
|
---|
We present the results of our proportional hazards models as hazard ratios in tables 1 and 2; 95 percent confidence intervals directly follow the hazard ratios.
View this table:
[in this window]
[in a new window]
|
TABLE 1. Latino(a) mortality risks of fair/poor self-ratings of health, stratified by birth/duration in the United States, 19891994*
|
|
View this table:
[in this window]
[in a new window]
|
TABLE 2. Latino(a) mortality risks of self-ratings of health, stratified by birth/duration in the United States, 19841994*
|
|
Table 1 presents the models, stratified by birth/duration in the United States. The overall mortality risk (right-hand column) for rating oneself in fair/poor health relative to better health was nearly twofold (hazard ratio = 1.80) over the subsequent follow-up period (net of covariates). Our stratified models show a monotonic increase of SRH on mortality risk as level of acculturation increases. That is, the mortality risk of fair/poor SRH for recent immigrants is 1.28 times that of those who rate themselves in better health, but is statistically nonsignificant. Among long-term immigrants, fair/poor SRH is associated with a risk of dying that is 1.74 times that of those who rate themselves in better health; this risk rises to 2.04 among native-born Latinos.
We performed a formal chi-squared check of the proportionality assumption for SRH and mortality risk. Although proportionality was confirmed with 95 percent statistical confidence among immigrants, the hazard ratios among the native born begin to converge over the course of the follow-up period. Thus, we specified piecewise-constant hazard models to assess differential mortality risk over several different time periods. We ran four separate regression models that specify two constants for the following time periods: model 1, 024 and 25108 months; model 2, 036 and 37108 months; model 3, 048 and 49108 months; and model 4, 060 and 61108 months. Rather than present the full results for each of these models, we present only the hazard ratios (table 2) for each acculturation level, controlling for the full set of social and demographic factors.
In model 1 (table 2), for example, a fair/poor rating of health is associated with a two and a half-fold or higher mortality risk for 2-year mortality follow-up (024 months) among all acculturation groups. However, although poor SRH is predictive of mortality beyond 2 years for native-born and long-term immigrant respondents, it is not predictive for recent immigrants (model 1, 25108 months). A similar pattern emerges when examining different periods of follow-up risk. That is, fair/poor SRH is predictive of mortality only for a very short period of risk (i.e., less than 2 years) among recent immigrants and is not a statistically significant predictor for any period of time beyond that. On the other hand, for both long-term immigrants and native-born respondents, fair/poor SRH is predictive of mortality risk for a much longer time period. However, the strength of this association diminishes over time such that fair/poor SRH is no longer predictive of mortality risk after an initial 5-year observation period.
 |
DISCUSSION
|
---|
Our results indicated that SRH has limitations in predicting mortality risk among Latinos. A previous study has shown that all race/ethnic groups exhibit similar mortality risks for fair/poor SRH (20
); we observe a similar risk among the pooled sample of Latinos in our study. However, our study indicates that these cross-ethnic comparisons may not be valid when immigrants make up a large portion of study samples. More specifically, although fair/poor SRH was associated with short-term mortality risk among those with low levels of acculturation, this rating was not predictive of long-term mortality risk (i.e., after 2 years). On the other hand, as levels of acculturation increase among Latinos, fair/poor SRH has stronger effects and longer-lasting predictive power for subsequent mortality risk. That is, the predictive power of SRH among the more acculturated should more closely match those of non-Hispanic White and non-Hispanic Black respondents who are born in the United States.
As a cautionary note, differential rates of return migration (by acculturation) could potentially bias the baseline mortality estimates, although these estimates are not of direct concern for our study. However, if those who rate themselves in fair/poor health are lost to follow-up because of return migration to Mexico, at higher rates than those who rate themselves in good health, then our results may be affected by this bias.
Our findings imply that the use of SRH for cross-ethnic comparisons of physical health may be problematic. Demographically, since foreign-born respondents make up greater percentages of survey samples (because they are becoming a greater proportion of the US population), the ability to quickly assess health for all subjects equally through the use of SRH becomes more problematic. Therefore, it is very important to control for levels of acculturation within and between groups for whom comparisons are being made so that potentially artifactual components of SRH can be factored out.
 |
NOTES
|
---|
Correspondence to Dr. Brian K. Finch, School of Public Health, University of California, 140 Warren Hall, Berkeley, CA 94720 (e-mail: bkfinch{at}uclink.berkeley.edu).
 |
REFERENCES
|
---|
-
Idler I, Benyamini Y. Self-rated health and mortality: a review of twenty-seven community studies. J Health Soc Behav 1997;38:2137.[ISI][Medline]
-
Angel R, Guarnaccia PJ. Mind, body, and culture: somatization among Hispanics. Soc Sci Med 1989;28:122938.[ISI][Medline]
-
Finch BK, Kolody B, Vega WA. Perceived discrimination and depression among Mexican-origin adults in California. J Health Soc Behav 2000;41:295313.[ISI][Medline]
-
Shetterly SM, Baxter J, Mason LD, et al. Self-rated health among Hispanics vs. non-Hispanic White adults: the San Luis Valley Health and Aging Study. Am J Public Health 1996;86:17981801.[Abstract]
-
Vega WA, Amaro H. Latino outlook: good health, uncertain prognosis. Annu Rev Public Health 1994;15:3967.[ISI][Medline]
-
Hummer RA, Rogers RG, Amir SH, et al. Adult mortality differentials among Hispanic subgroups and non-hispanic Whites. Soc Sci Q 2000;81:45976.[ISI]
-
Hummer RA, Rogers RG, Nam CB, et al. Race/ethnicity, nativity, and US adult mortality. Soc Sci Q 1999;80:13653.[ISI]
-
Singh GK, Siahpush M. All-cause and cause-specific mortality of immigrants and Native born in the United States. Am J Public Health 2001;91:3929.[Abstract]
-
Liao Y, Cooper RS, Cao G, et al. Mortality patterns among adult Hispanics: findings from the NHIS, 1986 to 1990. Am J Public Health 1998;88:22732.[Abstract]
-
Abraído-Lanza AF, Dohrenwend BP, Ng-Mak DS, et al. The Latino mortality paradox: a test of the "salmon bias" and healthy migrant hypotheses. Am J Public Health 1999;89:15438.[Abstract]
-
Burnam MA, Hough RL, Karno M, et al. Acculturation and lifetime prevalence of psychiatric disorders among Mexican-Americans in Los Angeles. J Health Soc Behav 1987;28:89102.[ISI][Medline]
-
Vega WA, Kolody B, Aguilar-Gaxiola S, et al. Lifetime prevalence of DSM-III-R psychiatric disorders among urban and rural Mexican Americans in California. Arch Gen Psychiatry 1998;55:7718.[Abstract/Free Full Text]
-
Hummer RA, Biegler M, DeTurk PB, et al. Race/ethnicity, nativity, and infant mortality in the United States. Soc Forces 1999;77:1083118.[ISI]
-
Kaplan MS, Marks G. Adverse effects of acculturation: psychological distress among Mexican American young adults. Soc Sci Med 1990;31:131319.[ISI][Medline]
-
Ebin VJ, Sneed CD, Morisky DE, et al. Acculturation and interrelationships between problem and health-promoting behaviors among Latino adolescents. J Adolesc Health 2001; 28:6272.[ISI][Medline]
-
Finch BK, Boardman JD, Kolody B, et al. Contextual effects of acculturation on perinatal substance exposure among immigrant and native-born Latinas. Soc Sci Q 2000;81:42138.[ISI]
-
Frisbie WP, Biegler M, DeTurk PB, et al. Determinants of intrauterine growth retardation and other compromised outcomes: a comparison of Mexican Americans, African Americans, and non-Hispanic Whites. Am J Public Health 1997;87:197783.[Abstract]
-
Frisbie WP, Forbes D, Pullum S. Compromised birth outcomes and infant mortality among racial and ethnic groups. Demography 1996;33:46981.[ISI][Medline]
-
Zhang S, Hayward M. Race, nativity and morbidity patterns: the effects of health selection, acculturation and socioeconomic circumstances. Presented at the 2001 Annual Meeting of the Population Association of America, Washington, DC, 2001.
-
McGee DL, Liao Y, Cao G, et al. Self-reported health status and mortality in a multiethnic US cohort. Am J Epidemiol 1999;149:416.[Abstract]
-
National Center for Health Statistics. National Health Interview Survey, 19891994. Computer file and documentation. Hyattsville, MD: US Public Health Service,1994.
-
National Center for Health Statistics. National Health Interview Survey: multiple cause of death public use data file, 19861997 survey years. Hyattsville, MD: US Public Health Service, 2000.
-
StataCorp. Stata statistical software: release 7.0. College Station, TX: Stata Corporation, 2001.
Received for publication July 18, 2001.
Accepted for publication January 11, 2002.