Lars Friberg (1920–2006), professor emeritus at Karolinska Institutet, was an internationally recognized pioneer in modern occupational and environmental medicine. Born and raised in Malmö, Sweden, Friberg pursued his medical training in Stockholm and completed his influential PhD in 1950, focusing on the health effects of chronic cadmium poisoning. His public health and environmental research career spanned over five decades, significantly contributing to understanding the toxicology of metals and other environmental hazards.

In 1957, Friberg was appointed professor of general public health and head of the Department of Environmental Hygiene at Karolinska Institutet. He later became the director of the Institute of Environmental Medicine in 1980, serving in both roles until his retirement in 1988. Even after his formal retirement, he continued his research as professor emeritus, focusing on the health impacts of metals such as mercury and cadmium and other chemical hazards. His research on toxic metals, air pollution, noise, and smoking gained international recognition, establishing him as one of the foremost experts in the field.

Friberg was also one of the editors of the influential Handbook on the Toxicology of Metals, a key reference in the field. His research on mercury toxicity, particularly regarding mercury accumulation in the brain and kidneys from dental amalgams, advanced the understanding of occupational exposure to toxic metals.

Friberg’s influence extended beyond toxicology. Alongside his colleague Rune Cederlöf, he co-founded the Swedish Twin Registry (STR) in the late 1950s. The registry remains a world-renowned resource for research on genetics, environmental exposures, and disease. The STR enabled important research on how environmental factors contribute to disease, using twins as a unique model to control genetic confounding factors. Their studies, particularly related to smoking and lung cancer, helped clarify the health risks of environmental exposures.

Establishing the STR was a meticulous effort. Friberg and Cederlöf tracked Swedish twin births between 1886 and 1925, manually contacting parish offices nationwide. This culminated in the first major questionnaire, distributed to approximately 12,000 twin pairs between 1959 and 1960. The registry has since expanded and evolved into a global leader in twin research, benefiting studies in environmental medicine, behavioral genetics, and genetic epidemiology.

Widely respected for his intellectual rigor, leadership, and mentorship, Friberg was affectionately known as the “great white boss” due to his distinctive white hair and commanding presence. A brilliant speaker and a generous mentor, he supervised many graduate students and contributed to numerous international expert committees. His accomplishments earned him prestigious awards and memberships, including a seat on the Nobel Assembly at Karolinska Institutet.

While best known for his research on toxic metals, Friberg’s contributions to twin studies also left a lasting legacy. His pioneering work continues to influence research in environmental medicine, genetic epidemiology, and behavioral genetics. Lars Friberg’s death in 2006 marked the loss of a giant in occupational and environmental medicine, but his groundbreaking work ensures that his legacy continues to shape these fields today.