Nashville-area employers negotiating benefits with health insurers for 2009 are seeing medical costs in their health plans rise 8% to 12%, local insurance brokers said. With companies facing challenges from a U.S. economic downturn, they're under more pressure to rein in expenses, prompting some companies to pass on more of the costs to their employees, change the mix of insurance offerings, or give employees incentives to live healthier lifestyles.