In Memoriam: Joseph Lewis Belsky, MD

Joseph Lewis Belsky, MD, died on Sept. 17, 2025, at the age of 99. He was a longstanding and beloved endocrinologist and teacher at Danbury Hospital and Yale School of Medicine (YSM).

His long and productive life began modestly in northern New Jersey. He loved reading and had an initial interest in becoming a writer or journalist but attended Drew University as a premedical student majoring in chemistry. He went on to obtain a master’s degree in chemistry from Wesleyan University and then attended Albany Medical College, graduating in 1955. He completed his internship at Boston Medical Center and residency in internal medicine and fellowship in endocrinology at Tufts Medical School and the Boston VA Medical Center. He moved to Connecticut and joined the medical staff at Danbury Hospital in 1964, spending the rest of his career there until retiring in his early 90s. He had a remarkable career in which he became known across the region as an outstanding clinical endocrinologist.

He served for three years in Japan as chief of medicine at the Atomic Bomb Casualty Commission, a longitudinal investigation studying the delayed effects of radiation from the Hiroshima and Nagasaki bombs. During that time, he made many lifelong connections with Japanese physicians, patients, and families. He subsequently served as chair of the medicine and endocrinology departments at Danbury Hospital as well as its first full-time director of medical education as it grew into a teaching hospital. He established Danbury Hospital’s research day, subsequently named the Joseph Belsky Research Day, to allow residents to present case reports and small studies, many of which went on to be published. He inspired many prominent academic endocrinologists who now serve in academic centers across the United States. In recognition of his many contributions to Danbury Hospital, this past May, an anonymous donor created the Joseph L. Belsky, MD, Endowed Chair in Medicine, which was awarded to the current chair of medicine at Danbury Hospital.

Belsky was a devoted member of the clinical faculty in the Section of Endocrinology and Metabolism at YSM. He attended on the Yale New Haven Hospital endocrine consult service for years and was much beloved by fellows for his teaching prowess and experience. He donated his time to do this as he loved teaching students, residents, and fellows, always with a smile and with gentle encouragement. He was also a longstanding attendee of Yale Endocrine Grand Rounds, providing keen clinical insights into fellows’ case presentations for decades. He was ever curious and had an insatiable appetite for learning. He engaged in clinical research throughout his long career.

One highlight was his involvement with Karl Insogna, MD, and Richard Lifton, MD, in defining a Connecticut kindred of patients with mutations in LRP5 causing very high bone mass. He was a co-author on the New England Journal of Medicine paper that reported this finding, which ultimately led Amgen to develop romosozumab, one of only three FDA-approved anabolic drugs for the treatment of osteoporosis. Excited by clinical aspects of this kindred, he subsequently recruited 370 patients and showed that the presence of torus palatinus correlated with higher bone mass irrespective of LRP mutations. He published this first-authored study, at the age of 77, in the leading clinical endocrinology journal. He served as a wonderful example of an engaged, intellectually driven, dedicated, and compassionate member of the Section of Endocrinology and Metabolism’s clinical faculty. In addition to his life as a physician, Belsky was a committed member of his community. He served in the navy during World War II before entering medical school.

In addition to serving on the Atomic Bomb Casualty Commission, as noted above, he served on the Board of Education in Ridgefield, Conn. He was devoted to Jane Belsky, his wife of 70 years, who died in May 2025.

Belsky is survived by four children—Stephen, Susan, David, and Martha—and significant others; and seven grandchildren. He was a physician, scholar, administrator, community member, husband, father, and grandfather who will be missed.