"I used to have to drag myself out of bed at 6 a.m. and go to work."

Kelly Close spends her workdays handing out financial and marketing advice related to diabetes. The rest of the time she just lives with the disease. "I feel pretty lucky that I was able to turn something that was negative into a positive force," she says of Close Concerns (www.closeconcerns.com), the diabetes consultancy she founded last year. "I also feel that the need for my services will continue to grow as diabetes and obesity worsen—they're problems we really need to get our arms around as a country, and around the globe."

Close has been diabetic for 17 years. By the time she graduated from business school, she was injecting seven shots of insulin a day, and checking her blood sugar almost as much. She balanced her personal health needs with working 80-hour weeks as a medical-technology analyst at Merrill Lynch, where diabetes became one of her specialties. As an investment idea, she got an insulin pump made by MiniMed (now owned by Medtronic Inc.) to see if the company's stock was worth buying. "Investors watched as it changed my life," she says. "It was my best stock recommendation early on."

A reputation for "knowing this stuff inside and out" followed, as did job offers. Becoming a chief financial officer was not of interest. Instead, the 35-year-old Close took a risk and launched her own business. "If it wasn't a job, there was no way for me to read all the journals, all the articles, all the books, and go to 15 or 20 conferences on diabetes a year, which I do," she explains. "I used to have to drag myself out of bed at 6 a.m. and go to work. Now I get right up, go to my home office, and begin the day."

Not surprisingly, Close is a promoter of professional specialization. "I like to think...there's a big argument for hiring someone who has been thinking about [a subject] day in and day out for the past 15-plus years—and who doesn't cost as much as McKinsey," where she worked happily from 1995 to 1997, she asserts. "This is kind of a new era where independence is fostered, encouraged, and appreciated—it's the time for the independent researcher, the independent manager, the independent writer—I'm mightily happy, and lucky, to be a major beneficiary of this. It's really allowed my business to flourish and grow."

Her 10 clients include public and private companies and venture capitalists who want advice on mergers and acquisitions, investment analysis, and product marketing and management. Some of her clients are also patients and their families, or individual investors, who want high-quality, customized research. "It was a big risk to leave a Wall Street job, but getting the business has not really been a problem," she says. "The hardest part has been to juggle everything: the conferences, the reports, the client calls. It gets busy." But, she adds, "I've been moved at how inspiring it has been to work at something that I am so close to personally."