Health Disparities Research Along U.S.-Mexico Border Reveals Surprises
By Bernice Wuethrich,

Thorny shrubs and mesquite lend the landscape a rough cover along the Lower Rio Grande in Southern Texas, where life can be as tough as the bristling brush—particularly for Mexican immigrants striving to settle in a new country. But what impact does this life—and the stress of migration itself—have on the mental health of immigrants?

To answer this question, Elena Bastida, Ph.D., an MBRS-supported researcher at the University of Texas-Pan American in Edinburg, and co-investigator Israel Cuellar, Ph.D., who is now at Michigan State University in East Lansing, conducted a study comparing the mental health of Mexican immigrants and native-born Mexican Americans living in the region.

Their study addressed past research indicating that recent Mexican immigrants tend to have better mental health and be higher achievers than native-born Mexican Americans. In fact, the literature suggests that the longer Mexicans reside in the United States, the more likely they are to report detrimental mental health conditions, something that has become known as the "mental health paradox."

But Bastida and Cuellar's recent results challenge the paradox. They found that length of residency and immigrant status have no bearing on depression, health status, life satisfaction, or self-esteem in study participants. On the other hand, factors such as income, age, gender, and acculturation significantly predict well-being. Indeed, the scientists' results suggest that the longer an individual resides in the United States, the less likely he or she is to be depressed.

Bastida's results are based on data from the Border Epidemiologic Study of Aging (BESA), of which she is the principal investigator. Beginning in 1995, Bastida and her colleagues interviewed a random sample of 1,370 Mexican-American households, some urban, some rural, all in the border region of Hidalgo and Starr counties in Texas. She grouped the respondents by age and has conducted follow-up interviews at 24-month intervals, collecting three waves of data, with a fourth underway. For the mental health and residency study, Bastida compared native-born Mexican Americans to Mexican immigrants who had lived in the United States for 15 years or less, 16-30 years, 31-45 years, and 46 years or more.

Bastida suggests that methodological differences—in population samples, mental health measures, and environmental factors—could partly explain the strikingly different results obtained by the BESA study. Specifically, she suggests that three factors may explain why length of stay or immigrant status had no effect on depression scores or well-being in her study.

First, previous studies were based on interviews with Hispanics who had been in the United States an average of 15 years or less, whereas BESA encompasses those who have been here three times as long. Most previous work did not study Mexican immigrants who had lived the majority of their lives in the United States, as did Bastida's study.

"Maybe earlier studies were catching people in the most difficult time of their adjustment," she speculated.

Secondly, Bastida's study population was significantly older than those in other studies. The youngest person in the BESA study was 45 years old and the mean age was 62.

Finally, the BESA study participants all lived along the U.S.-Mexico border, where Spanish is commonly spoken and 85 to 95 percent of the general population is of Mexican origin. Bastida suggests that these environmental conditions may greatly influence adjustment to living in the United States.

"In our border area, ties with Mexico are very strong," Bastida noted. The mental and physical proximity to Mexico may have a protective effect on immigrants' mental health, she believes.

In addition to investigating mental health issues, Bastida has used BESA data to examine a number of patterns of health behaviors and disease, among them diabetes. Adult Mexican Americans have two to four times the prevalence of diabetes as adult non-Hispanic Caucasians, and are at greater risk from suffering from its complications. BESA data has shown that personal income and depression are associated with diabetes. Those who earn less than $7,000 a year are six times more likely to be diabetic compared to those with annual incomes of $50,000 or more, and those who are depressed are 1.5 times more likely to be diabetic compared to those who are not. Other work by Bastida indicates that Mexican Americans in south Texas are under-treated for diabetes.

Bastida is expanding the scope of her study to include physical activity, nutrition, neighborhood conditions such as safety and the availability of fresh produce, and the relationship between religion and health.

Reference: Cuellar I, Bastida E, Braccio SM. Residency in the United States, subjective well-being, and depression in an older Mexican-origin sample. J Aging Health 2004;16:447-66.