(Bloomberg) -- For 110 years, four generations of Mills family members earned their money by expanding their great-grandfather’s Chicago apron business into a medical supplier that ranked among the nation’s largest private companies. But soon after Democrats turned their attention toward raising taxes for the wealthy this year, the family signed a deal to cash out billions. It was no coincidence, according to people close to the more-than $30 billion transaction, which sold part of Medline Industries Inc. to a consortium of Wall Street investors in the health-care industry’s biggest leveraged buyout.