Thousands of Latino patients stream though the East Los Angeles practice of Dr. Hector Flores and his partners each year.
The older ones go to the family practice with arthritis and hypertension, the younger ones with diabetes and asthma.
What surprises Flores, however, is not how sick they are, it is how sick they are not.
Overall, Flores said, his patients are much healthier than one would expect given their low levels of income and education, factors epidemiologists long have known are linked to poor health.
“You can predict in the African American population, for example, a high infant mortality rate,” he said recently, “so we would think a [similarly] poor minority would have the same health outcomes.
“But they don’t. They’re not there,” he said, referring to outcomes among Latinos.
Why Latinos aren’t sicker -- a phenomenon known to health experts as the Latino paradox -- is puzzling to public health experts, given the link between disadvantage and high disease and mortality rates.
In overall mortality rates and infant mortality rates, two standard measures of a population’s health, Latinos’ numbers approach and sometimes surpass those of whites.
In Los Angeles County in 2003, the age-adjusted mortality rate for Latinos was 535 per 100,000, 33% less than for non-Hispanic whites and 52% less than for blacks, according to the most recent data from the county’s Department of Public Health.
Nationally that year, Latinos’ mortality rate was 621, 25% less than whites’ and 43% less than blacks’, according to National Vital Statistics Reports, published by the Centers for Disease Control and Prevention.
Latinos’ infant mortality rates reflect a similar pattern. Locally, the rate was 5.2 per 100,000 in 2003, 16% higher than whites’ and 57% less than blacks’. The national rate was 5.7, about the same as whites’ and 58% less than blacks’.
“It violates one of the most predictable patterns we see in most areas of the world and for most diseases,” said Dr. Paul Simon, chief epidemiologist for the county’s Public Health Department.
“The question is, ‘What is the Latino population doing right?’ ”
The reasons for the paradox are a matter of some debate. Some scholars attribute it to immigration, which may draw selectively from the ranks of the hale and hardy.
Another possibility is that many immigrants return to their home countries when seriously ill, skewing mortality statistics in this country.
But increasingly, researchers are suggesting that such factors as diet, lifestyle choices and strong social support networks are the key to Latinos’ better-than-expected health.
“They’re not taking some secret Aztec herb they didn’t tell you about,” said David Hayes-Bautista, an early observer of the Latino paradox who directs UCLA Medical School’s Center for the Study of Latino Health and Culture.
It’s worth figuring out what is making the difference, he added, because “we could all be better off for it.”
As the immigration debate heats up and the cost of healthcare soars, the phenomenon is attracting attention from social scientists and public health officials. It was first noticed, though, in the 1970s and 1980s by researchers looking at infant and overall mortality rates in Texas and California.
Scholars tended to view the findings as wrong or anomalous, assuming that Latinos’ relatively disadvantaged socioeconomic status put their health status more on par with blacks’.
As data accumulated, covering broader swaths of the country and longer periods, skepticism turned to curiosity.
Kyriakos Markides, who in 1986 coined the term “Hispanic epidemiological paradox,” described scholars’ shift in recent years as remarkable.
“Nobody talked about it then,” said Markides, a professor of socio-medical sciences at the University of Texas Medical Branch, speaking of a generation ago. “People just ignored the data or assumed that disadvantaged populations have high mortality. Now, it’s the leading theme in the health of the Hispanic population in the United States.”
The paradox remains controversial, in part because its first-blush message -- that Latinos are less ill than expected -- might lead people to believe that the group doesn’t need scarce healthcare dollars.
Hayes-Bautista recalled an incident in the 1990s when a colleague he had just briefed on the paradox asked him to keep the data to himself, saying she feared services for Latinos could be cut.
“I guess it’s the triumph of -- I hate to say -- of ideology over data,” he said.
In addition, some doctors and other medical professionals aren’t familiar with the concept, which is a broad statistical phenomenon, not necessarily true in individual cases or practices.
Even some who are aware of the phenomenon question its significance, saying they still must focus on treating individuals.
“Somebody at 36,000 feet can stand back and say this is all true and verified, but I still have a clinic full of diabetics, hypertensives, people with high cholesterol,” said Dr. Felix Nunez, the medical director of South Central Family Health Center, a Los Angeles clinic that serves a large Latino population.
Scholars also note that it seems to apply more to some diseases than to others. Data suggest Latinos experience less lung and breast cancer than whites, but they also are more likely to have diabetes, cervical cancer and AIDS.
The paradox’s power appears variable, too, waning by some measures with each generation and fluctuating by place of origin. Some researchers say that, for unclear reasons, it is most apparent among Mexicans and less so among Puerto Ricans.
“You never get a complete picture of what’s going on,” said Alberto Palloni, a sociology professor at the University of Wisconsin and president of the Population Assn. of America. “You get patches, halfway photographs of what is happening.”
Studies have indicated, however, that Latinos drink less alcohol and smoke less than their white counterparts, although their healthful behaviors appear to wane with greater acculturation in the United States.
Several studies have found that the children and grandchildren of foreign-born Latinos tend to smoke, drink and use illegal drugs more than their parents and grandparents. And some research suggests that they are less likely to breast-feed or stick to the healthier diets of their forebears.
“You can see it in obesity rates; they’re very high in Mexican children,” said Dr. Leo Morales, an associate professor of medicine and public health at UCLA who has written about the paradox.
“That portends high disease rates for cardiovascular disease, diabetes, all the obesity-related complications.”
Ana F. Abraido-Lanza, an assistant professor at Columbia University’s Mailman School of Public Health, cited a greater availability of fast food in the United States and social factors, including a more relaxed attitude toward drinking.
Another possible culprit is stress.
A 1999 study published in the journal Social Forces found that Puerto Rican women who had recently moved to the mainland United States reported fewer stressful “life events” than mainland-born peers, such as being physically abused or being close to someone with a serious drug or alcohol problem.
Strong social networks could be helping them.
“A strong family and social network can reduce stress and can provide emotional support during difficult periods,” Simon said. “All those things translate into people living longer and living healthier.”
A yet-to-be-published study of Chicago neighborhoods found that in enclaves with high numbers of Latino immigrants, 5% of such immigrants had asthma, a lower percentage than for whites, blacks and U.S.-born Latinos in the same area.
That figure jumped to 22%, higher than for all other groups, among Latino immigrants when they lived in neighborhoods with few of their immigrant peers, even when such factors as health insurance and poverty were accounted for.
“There seems to be something about neighborhood social context that matters,” said Kathleen Cagney, a University of Chicago assistant professor and lead author on the study, which is to be published in the American Journal of Public Health.
In this case, Cagney said, she believes the trust and solidarity in their neighborhoods led foreign-born Latinos outdoors and away from indoor irritants such as mold and cockroach infestations.
No expert offered a comprehensive explanation of the paradox, and some wondered whether one was possible.
“In some ways, it’s like the more you get into it, the more complex it seems,” said Dr. Elena Fuentes-Afflick, a professor of pediatrics at UC San Francisco.
Like Flores, she believes the truth ultimately will involve a combination of factors.
UCLA’s Hayes-Bautista believes the answer exists, if only health experts look hard enough.
“There must be an explanation,” he said. “We just need to put the time in to understand.”