(Reuters) -Humana reported third-quarter profit that beat Wall Street estimates on Wednesday, helped by higher premiums and medical costs which were in line with the health insurer's expectations. The company is one of the largest providers of Medicare Advantage plans, under which the U.S. government pays private insurers a set rate to manage healthcare for people 65 and older, as well as those with disabilities. The health insurance industry has been battling stubbornly high costs for the last two years ...