Cindy Crawford's Heartfelt July 4th Weekend
07/07/2008 AT 09:55 AM EDT
In the '70s, the supermodel's sibling, Jeff, was a patient at University of Wisconsin Children's Hospital (now the American Family Children's Hospital in Madison. Tragically, however, he died of leukemia in 1975, shortly before his fourth birthday.
Despite the loss, Crawford believes her brother received the best care possible, which has launched her long commitment to the institution and its programs.
"When I was able to start raising money and awareness," Crawford, 42, told WiscTV.com, "I was able to choose where do I want to give back in my life, and this just was the first place that popped into my head."
This weekend, Crawford served as honorary chair of the fourth reunion of childhood cancer survivors in Madison, weekend, her fourth such service to the cause (after similar appearances in 1993, 1998 and 2003), the Associated Press reports.
The University of Wisconsin says Crawford has been giving her time and money to the UW Pediatric Oncology program for nearly two decades.
See Cindy Crawford on the cover of PEOPLE's 1993 Most Beautiful People issue