It is the most costly health problem in the United States today.

It is the No. 1 killer from birth to age 44.

It strikes nearly one of three Americans every year, hitting men and the poor the hardest.

Yet, unlike well-known causes of death such as heart disease and cancer, the study of injury -- from auto accidents to shootings, falls, and suicides -- receives proportionately little support or direction from the federal government.

That is the conclusion of a National Academy of Sciences panel that found injury to be "the principal public health problem in America today" and urged new federal initiatives to understand, prevent and treat the problem.

Calling this the "last major plague of the young," the 16-member committee complained in a report released yesterday that injuries "destroy the health, lives and livelihoods of millions of people, yet they receive scant attention, compared with diseases and other hazards."

"The time has come for the nation to address this problem -- a problem that affects all Americans and one on which an investment in research could yield an unprecedented public health return," said panel Chairman Dr. William Foege, an assistant surgeon general with the federal Centers for Disease Control (CDC) and former head of the agency.

The committee recommended that a new Center for Injury Control be set up to coordinate and lead research on injuries of all types. It suggested that this center be located within CDC, reinforcing but not replacing the "unfocused" and "undersupported" efforts scattered through the government.

The study, prepared under congressional mandate for the Department of Transportation, comes amid growing grass-roots efforts for stronger sanctions against drunken driving, as well as mandatory state requirements that seat belts be used.

The study amassed strong evidence on the overall impact of injuries in this country:

* Injuries caused 143,000 deaths in 1983 as well as 70 million nonfatal injuries severe enough to require medical care or restrict activity for a day or more.

* While they are the fourth-leading cause of death overall -- behind heart disease, cancer and stroke -- injuries account for almost half of deaths of children aged 1 to 4, more than half of deaths of those 5 to 14 and nearly four-fifths of the deaths of those 15 to 24. They remain the leading cause of death up to the age of 44, when chronic diseases begin to claim more lives.

* Motor-vehicle crashes are the major cause of severe disability and death from injury, accounting for 44,800 deaths in 1982 and 3.2 million injuries. Unintentional and intentional deaths from firearms ranked second with 33,000 deaths, followed by falls and jumps, drowning, poisoning, fires and burns, suffocation and hanging, cutting and poisoning by motor-vehicle carbon monoxide. Overall unintentional deaths totaled 94,100 that year, with 28,200 suicides and 22,300 homicides.

* Because they strike at younger ages, injuries cause the loss of more years of working life than all forms of cancer and heart disease combined. They are the leading cause of physician contacts, account for 25 percent of hospital emergency room visits and are the most common cause of hospitalization for people under 45. More than 80,000 people are disabled annually with permanent injuries to the brain or spinal cord alone.

* The direct medical expenses as well as the indirect economic impact of injuries cost an estimated $75 billion to $100 billion each year in this country.

* Men are more than twice as likely as women to suffer fatal injuries.

* Death rates are also higher in rural and low-income areas. "High-risk jobs, low-quality housing, older cars and such hazardous products as space heaters tend to be concentrated among poorer people," the report found.

* Alcohol plays a major role in injuries. Almost half of fatally injured drivers and substantial proportions of adult passengers and pedestrians killed in car accidents, as well as those killed in falls, drownings, fires, assaults and suicides are legally drunk, as defined by blood alcohol concentrations of 0.10 percent or higher. A study of emergency room patients found that alcohol was detected in 30 percent of persons injured on the road, 22 percent injured at home, 16 percent injured on the job, and 56 percent injured in fights or assaults.

* Total annual spending for nonmilitary injury research by the government is about $112 million, less than 7 percent of the 1983 federal research budget for cancer and heart disease combined.

The committee called for more research in areas such as the mechanisms for brain and spinal cord injuries as well as their treatment, the cause and prevention of falls (the leading cause of nonfatal injury), as well as the general susceptibility of children, women, and the elderly to tissue damage.

"It is outrageous" that injuries should be receiving so little funding, the committee's vice chairman, Susan P. Baker of Johns Hopkins University, said in an interview yesterday. "There is a desperate need for new funds."

"One reason this has been neglected is that for a long time we spoke of the inevitability of accidents. It kept us from thinking about injuries and preventing and reducing their effects. Just in the past decade we began thinking about . . . how our physical and social environment contributes to the likelihood of injury and how our medical care system responds."