The nation's 20.5 million Hispanics face major barriers to getting health care and have higher rates of some diseases such as diabetes and AIDS.

In the first comprehensive health survey of the country's fastest-growing minority group, researchers found that Hispanics tend to go to the doctor less often than non-Hispanic whites and blacks largely because they are poor and lack health insurance. Cultural factors ranging from difficulty speaking English to fear of medical technology plus; for illegal aliens, fear of deportation, also play a role.

Many of the District's estimated 85,000 Hispanics, who recently emigrated to the U.S., are living in poverty without their families.

"Within the first six months {of arriving}, they will face problems of conduct, such as looking for alcohol, and develop psychosomatic symptoms, such as insomnia, headaches, gastritis, problems of weakness, lack of appetite and a desire to cry," said Juan Romagoza, director of Clinica del Pueblo, a Hispanic health clinic in Adams-Morgan, through an interpreter.

Even though the public clinic with a Spanish-speaking staff sees patients free of charge, many Hispanics still do not seek medical assistance unless they are critically ill, Romagoza said.

To examine the health status of Hispanics, the federal government conducted a major survey -- called the Hispanic Health and Nutrition Examination Survey, or HHANES -- of 11,000 Hispanics between 1982 and 1984. The first comprehensive analysis of this data was published in last week's Journal of the American Medical Association and as a special supplement to December's Journal of the American Public Health Association.

By the year 2000, the Hispanic population is expected to reach 31 million, making it America's largest minority group. Yet there are several distinct Hispanic populations in the U.S. Most of the estimated 250,000 Hispanics in the Washington area are from Central America. In New York City, most are from Puerto Rico; in Florida, they are largely of Cuban ancestry; and in Texas and California, the majority were born in Mexico.

In general, Hispanics are less likely to have medical insurance than any other group. In 1988, the latest year for which statistics are available, 13 percent of the population lacked health insurance overall: 10.2 percent of whites; 20 percent of blacks and 32 percent of Hispanics.

"The uninsured are the less educated, the poor and the sicker Hispanics," said Fernando M. Trevinao, director of the Center for Cross-Cultural Research at the University of Texas Medical Branch in Galveston.

Non-Hispanic whites and blacks also go to the doctor more often -- an average of 4.8 times per person per year -- compared to Mexican Americans, who visit a physician 3.7 times a year.

Experts once believed that Hispanics don't go to doctors because they choose instead to go to a curandero or a herbalista, who are folk medicine practitioners, but the HHANES survey found that only 4.2 percent of Mexican Americans had seen a folk healer in the previous year.

Even with the lack of medical care, Hispanics appear to live about as long as whites, said Olivia Carter-Pokras, a statistician with the National Center for Health Statistics. In a 1980 Texas study, the only year for which estimates are available, Hispanic men lived an average of 69.6 years and white men lived 70.2 years; Hispanic women lived 77.1 years and white women lived 78.1.

But "looking at how long we live is not enough," said Jane L. Delgado, president of the National Coalition of Hispanic Health and Human Service Organizations. "You have to look at the quality of that life."

While Hispanics get cancer less frequently, they are three to five times more likely than non-Hispanic whites and blacks to develop adult-onset diabetes and to suffer complications from the disease.

Lack of financial resources to pay for care is one reason. A 21-year-old Hispanic woman in the District recently developed a form of diabetes that requires her to take insulin, said Sister Maria Ceballos, medical clinic coordinator of the Spanish Catholic Center Medical Clinic in Mount Pleasant. But the woman can't afford to buy the insulin she needs, and she is afraid to apply for medical assistance because she is an illegal alien and does not want to be picked up by immigration officials. "Her biggest concern is that she is going to end up in a coma," from her uncontrolled diabetes, Ceballos said.

A 1986 University of Texas study of 17 Texas border counties found that uncontrolled diabetes in the Hispanic community led to a number of preventable complications. Of all the cases of diabetes-caused blindness identified in the study, researchers concluded that 60 percent could have been prevented with proper treatment, as could 51 percent of kidney failures and 67 percent of diabetes-related amputations of feet and legs. Preventable amputations alone cost $40 million, Delgado said.

The problems seen with diabetes extend to other diseases as well. Ceballos described a woman with breast cancer who delayed treatment so long, the cancer spread, seriously reducing her chances of survival.

The survey also measured infant health. For non-Hispanic whites, the infant mortality rate was 8.3 per 1,000 births, 17.2 for blacks, and 8.7 for Hispanics overall, a statistically significant difference when compared to whites.

Pregnancy is a particularly stressful time for mothers, said Maria Gomez, director of Mary's Center for Maternal and Child Care, a clinic run by midwives in Adams-Morgan that delivers 240 babies a year. Employers tend to fire women from their low-paying jobs around the sixth month when they can no longer hide the pregnancy, she said.

AIDS, too, is beginning to have an impact. While Hispanics only make up 7.9 percent of the population, they account for 14 percent of the AIDS cases nationwide, according to the Centers for Disease Control, including 21 percent of AIDS cases among women and 22 percent among children.

AIDS is not yet a major problem among the District's Hispanic population, accounting for only 3 percent, or 71 of the 2,537 cases reported to the D.C. Commission of Public Health as of October 1990.

The HIV testing program at Clinica del Pueblo actually showed a decline. In 1989, 5.8 percent of the 121 people tested at the clinic were positive; that dropped to 3 percent of the 289 people tested in 1990. Romagoza, however, worries that those tested are not among those at highest risk of contracting the disease, including gay men, intravenous drug users and prostitutes.

Several federal studies examined the changes in behavior as Hispanics moved from poor, rural communities in South and Central America to urban areas in the U.S. Researchers found that as Hispanics learned English and became assimilated into North American culture, they picked up some of its worst health habits, such as increasing their use of illegal drugs -- up to 25 times greater for cocaine. Cigarette and alcohol consumption also increased for some groups.

"The longer people are here," Delgado said, "the more likely they are to drink and smoke. The more they speak English, the worse they behave."