Fewer working-age adults are uninsured or underinsured in Massachusetts since the state mandated health insurance coverage in 2006, according to a report released last week by the Robert Wood Johnson Foundation. The proportion of uninsured adults fell from 18.7% in fall 2006 to 14.5% in fall 2007, while the proportion of underinsured adults fell from 7.3% to 5.6%. Low-income and young adults and small business employees saw the largest gains in coverage, a related analysis found. Massachusetts Hospital Association President and CEO Lynn Nicholas said the reports “clearly demonstrate the success of Massachusetts health care reform in reaching the people most in need of obtaining adequate and affordable health care.” She added, “The hardest work may still be in front of us as we strive to sustain these successes in the midst of very difficult economic conditions. We have to find a way to ensure that we keep covering people while avoiding both the underinsurance pitfall and the self-defeating trap of underpaying providers who are needed to care for the insured and underinsured alike.”