Los Angeles , California ( CNN ) -- Casey Johnson , heiress to the Johnson & Johnson fortune , died of natural causes related to diabetes , the Los Angeles County coroner said Thursday . The 30-year-old socialite was found dead at a friend 's home January 4 , authorities said . Johnson was one of the great-great-granddaughters of Robert Wood Johnson , a co-founder of the pharmaceutical giant , and was the daughter of Woody Johnson , owner of the New York Jets professional football team . She died of diabetic ketoacidosis , the coroner found . The Mayo Clinic describes the condition as a serious complication of untreated diabetes . Johnson was in the news recently because of her relationship with Internet and reality television star Tila Tequila . Several messages on Tequila 's official Twitter page mentioned Johnson in the wake of her death . `` I ca n't stop these haunting visions of her and I . We made such a lovely couple , only beginning to spend the rest of our lives together , '' a posting said the day after Johnson died . `` Everyone please pray 4 my Wifey Casey Johnson , '' Tequila wrote the day of Johnson 's death . `` She has passed away . Thank u for all ur love and support but I will be offline to be w family . '' Johnson 's family also expressed sadness . `` The Johnson family is mourning their tragic loss and asks for privacy during this very difficult time , '' a family representative said in a statement on the Jets ' Web site . `` The entire New York Jets organization is saddened at the news that Casey Johnson ... has passed away . '' CNN 's Tim Langmaid and Brittany Kaplan contributed to this report .
Coroner says natural causes related to diabetes caused death of Ashley Johnson . Note : Johnson died of a serious complication of untreated diabetes . The 30-year - old had a high - profile relationship with reality TV star Tila Tequila .