The WorldTrade Center (WTC) Medical Working Group is pleased to submit its second annual report on the state of 9/11 health. We were charged two years ago with advising you about health issues that are related - or potentially related - to the September 11, 2001 terrorist attacks on the World Trade Center, and have continued to meet regularly to review and report on the evolving research in this field. In our first report, we reviewed seven years of published research about health effects resulting from the attacks and WTC collapse.This body of research described short-term health effects occurring one to three years after the event, and findings are summarized on page 2. In the past 12 months, additional findings have been published, including some that address midterm health effects among adults, five to seven years after 9/11.This newer research suggests that, while the vast majority of people exposed to the attacks on 9/11 and its immediate aftermath are healthy and symptom-free, thousands of exposed individuals continue to suffer from WTC-related mental and physical health conditions, and some of these conditions are likely to be chronic. Of particular note are new epidemiological findings by the WTC Health Registry, which has been tracking the health of a large, voluntary sample of 71,000 exposed individuals since 2003 through periodic surveys.The results are published this year in the Journal of the American Medical Association (JAMA), and they indicate reports of high levels of new asthma diagnoses since the attacks, especially during the first 16 months after 9/11, and sustained and late-emerging posttraumatic stress symptoms. At the time of the second survey, five to six years after 9/11, one in ten adult enrollees reported having been diagnosed with new asthma. New onset symptoms of asthma five to six years after 9/11, however, were comparable to expected levels and were not linked to the degree/intensity of WTC exposure. In the same survey, nearly one in five enrollees reported experiencing symptoms of posttraumatic stress. Many of those developing symptoms years after 9/11 also had experienced other life stressors subsequent to the attack, such as losing a job or inadequate social support. Several newly published studies suggest that WTC-related mental and physical health conditions often can occur together, and in fact, 10-25% of people currently being treated by the WTC Centers of Excellence (see WTC Patient Population Report beginning on page 10) are being treated for both mental and physical health conditions. Fortunately, monitoring and treatment continues to be available in the NewYork City area for those whose health has been affected by 9/11 thanks to a combination of federal and City funding. Our state of knowledge about the short-term health effects of 9/11 has come into sharper focus since the formation of the WTC Medical Working Group in June 2007. With this report, we better understand the longer-term health care needs of exposed individuals, in particular those who may have developed chronic conditions that can seriously affect quality of life. For our first annual report on 9/11 health in 2008, the WTC Medical Working Group reviewed nearly 100 studies published from 2001-2007. Most of these studies examined the health of rescue and recovery workers one to three years after their exposure to the WTC disaster, although some studies also included residents and building evacuees. Physical and mental health findings were remarkably consistent across studies and are summarized in this report. Since the release of its first annual report in September 2008, the WTC Medical Working Group has identified 75 new studies published about WTC-related issues in peer-reviewed literature. Forty-eight examined health impacts or exposures and were relevant to the purpose of this report. Among relevant studies, the majority (36) examined mental health and 13 studies addressed physical health. The new research findings, summarized below, largely support previously published research. Most studies continued to focus on the short-term health of adults one to three years after the disaster, although a few studies now have examined the mid-term health of adults five to seven years after 9/11. Continued research is needed to better understand mid-term health impacts on adults, but a broad picture has begun to emerge. A large epidemiologic study conducted in 2006-2007 by the World Trade Center Health Registry provides the most recent information on mid-term health impacts of 9/11.The burden of probable posttraumatic stress disorder (PTSD) among enrollees (19%) was slightly higher than previously published estimates (16%) from 1-3 years after the event, and post- 9/11 risk factors such as job loss or lack of social support were strong predictors of posttraumatic stress symptoms at the time of the survey.These findings from the WTC Health Registry highlight the effects of compounded stresses and traumas on this exposed population. In terms of physical health findings, 10% of adult enrollees reported receiving a new diagnosis of asthma after 9/11. While the bulk of asthma symptoms developed soon after 9/11, many symptomatic adults appear to have delayed seeking care for these symptoms. These mid-term health findings from the WTC Health Registry, described in more detail below, as well as the WTC Patient Population Report on page 10, indicate that mental and physical health problems persist among thousands of adults who were exposed to the WTC collapse. They also indicate that many have not yet sought care, particularly for PTSD.The persistence of both mental and physical health problems suggests that some of the symptoms have become chronic and may require care for the foreseeable future.