CHICAGO (CBS) — As he awaits a kidney transplant, Chicago Police Supt. Eddie Johnson has lost 46 pounds, and doctors have told his son to shed some weight as well before he can donate his kidney to his father.

Johnson confirmed the weight loss Tuesday morning, and said he hopes to have the transplant by September.

“We’re getting dangerously close to it,” a smiling Johnson told CBS 2 Morning News. “So I’m hoping within the next month we’ll have it done, because I really want to get it done, so I can get back to the work at hand, and that’s to reduce this gun violence in the city of Chicago.”

The city’s top cop revealed he suffers from a rare kidney disease earlier this year, after falling ill at a press conference in January.

He was diagnosed with a kidney disease at age 25 and was told his kidneys would shut down within a couple of years. He took care of himself and has not required dialysis, even 31 years later. He also has stepped up his exercise program this year – including 40 minutes of cardio every day – as part of the preparation for a kidney transplant.

Johnson has been on a waiting list for a kidney transplant at Rush University Medical Center, and his 25-year-old son Daniel is one of the best matches, and both are preparing for the operation.

Chicago Police Department spokesman Frank Giancamilli confirmed Johnson’s son needs to lose 3 pounds before the transplant.

Johnson said he originally hoped to receive the transplant in July, but his doctors have been taking a cautious approach to make sure his son is healthy enough to donate his kidney before going forward with the operation.

“They are really, really good at making sure the donor is okay,” Johnson said.

The superintendent has said doctors have told him losing weight before the transplant will reduce the recovery time after surgery.

Johnson will join Illinois Secretary of State Jesse White at the Thompson Center on Tuesday for “Wave Away The Waiting,” a health fair to raise awareness about the importance of organ and tissue donation.

The event is part of National Minority Donor Awareness Week. According to White’s office, half of the 4,700 people waiting a transplant in Illinois are minorities.

“I think there’s a lot of myths out there concerning donations in the minority community, so we need to put all that to bed,” Johnson said.

Since he found out he would need a new kidney, Johnson has been an active supporter of Gift of Hope Organ & Tissue Donor Network.

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