Clark Tibbitts, 82, an expert on the process of aging who designed and directed the first National Conference on Aging more than 30 years ago and became an aggressive promoter of gerontology as a major government responsibility, died Oct. 11 at a hospital in Dover, N.H., after a heart attack.

Mr. Tibbitts, a resident of Rockville, was visiting a daughter when he was stricken.

He retired in 1983 from the staff of the commissioner on aging within the Department of Health and Human Services after a 34-year government career devoted entirely to problems and issues involving the aging. At the time of his retirement he was a specialist in international issues involving aging.

John M. Cornman, executive director of the Gerontological Society of America, said Mr. Tibbitts "was among the first to recognize the impacts the growing number of older people would have on our society. He was instrumental in launching important educational research and service programs responding to the needs of older people."

Mr. Tibbitts coined the phrase "social gerontology," and was one of the earliest advocates of the concept that specific programs for the elderly should be viewed as a package instead of a collection of unrelated health, housing or income supplement programs.

He came to Washington as a specialist on aging in 1949 to join the old Federal Security Agency, the predecessor of the Department of Health, Education and Welfare, which was subsequently replaced by the Department of Health and Human Services. He was chairman of the FSA committee on aging and geriatrics.

Before coming to Washington he had been director of the Institute for Human Adjustment at the University of Michigan for 12 years, and in that capacity he organized the first general conference on aging in the United States in 1947. In 1950 he directed the first National Conference on Aging, the predecessor of the White House Conferences on Aging.

A native of Chicago, Mr. Tibbitts graduated from the old Lewis Institute, which is now the Illinois Institute of Technology, and he did graduate study at the University of Chicago. During the early 1930s he worked for the old Federal Emergency Relief Administration and the Works Progress Administration in Washington, then transferred to Detroit where he directed a nationwide health survey for the WPA.

Mr. Tibbitts, the author of several books and articles on the aging process, was instrumental in establishing the government publication Aging, and he also helped organize the International Association of Gerontology.

He is survived by his wife, Helen Griffin Tibbitts, of Rockville; two daughters, Helen Jean Thiebaux of Fort Washington and Ann Tibbitts Schulz of Newton, Mass; a stepdaughter, Alice Mailhot of Ypsilanti, Mich.; 12 grandchildren and two great-grandchildren.