DAYTON — More than half of Ohioans covered by the expansion of Medicaid are employed but mainly in low-wage jobs with no benefits and little opportunity for advancement, according to a study released today by Families USA. About 300,000 Ohioans (50.5 percent) of those benefiting from Gov. John Kasich’s decision to accept federal funding to expand Medicaid to most low-income, able-bodied adults are working in such occupations as sales, food service, office and administrative support, the study found. That data reflects the state of the current labor market in Ohio in which about a third of all job openings are in low-wage occupations, according to the most recent tally of online help-wanted ads from OhioMeansJobs. The survey also indicates that an unwillingness to work is not the driving force behind the surge in Medicaid enrollment since expansion began last year, said Cathy Levine, executive director of the Universal Health Care Action Network of Ohio. “We’ve moved from solid middle class jobs that pay a living wage with benefits and retirement, to low-wage jobs with no benefits or future,” Levine said.