Another of his former clubs, AFC Telford United, confirmed the news this afternoon.
In a tweet, the club said: “AFC Telford United are extremely saddened to announce the passing of former player Stephen Jagielka. The former skipper played for the club between 2007 and 2009 under Rob Smith and Larry Chambers.
“All our thoughts at this difficult time are with Steve's family and friends.”
Shropshire-based Steve played for Sheffield United alongside his younger brother under Neil Warnock in the 2003/04 season after joining from Shrewsbury Town, but did not make a competitive appearance.
After leaving the Blades the former Stoke City youngster went on to play for Accrington Stanley, helping them to promotion from the Conference in the 2005/06 season, before spells at clubs including Droysden and Hednesford Town.
His brother Phil has made more than 250 competitive appearances for Sheffield United across two spells since coming through the club’s youth set-up.
In a statement, the Blades said: “Sheffield United is deeply saddened to hear of the passing of former player Steve Jagielka – brother of current defender Phil – at the age of 43.
“The condolences of all at the Blades are with Phil and the rest of the Jagielka family at this difficult time.”
A spokesperson for Shrewsbury Town, where Jagielka made close to 200 appearances between 1997 and 2003, said: “All at Shrewsbury Town is deeply saddened by the news and sends their support and condolences to Steve's family at this sad time.”