A box of 55-year-old computer punch cards has yielded a wealth of scientific data on high-density lipoprotein (HDL), commonly known as “good” cholesterol.

Created by scientist John Gofman, Ph.D., at the United States Department of Energy’s Lawrence Berkeley National Laboratory between 1954 and 1956, the cards detail the HDL levels of nearly 2,000 of the department’s employees.

The cards were abandoned in the 1960s as Gofman went on to other work, but were rediscovered in 1988 by Berkeley National scientist Paul Williams, Ph.D., who spent the following decade tracking down almost every single person catalogued in the study and surveying them or their family about their heart health.

His results suggested that the presence of HDL significantly reduces the risk of developing cardiovascular disease.

Williams’s results, which constitute the longest-ever study of HDL, appear in the journal Atherosclerosis.

Previous studies have suggested that eating foods rich in HDL may also lower the risk of developing Alzheimer’s disease and other neurodegenerative disorders, as well as mitigating aterio- and atherosclerosis.