21 September 2012 | $10 CREDIT: MIKE KEMP/GETTY IMAGES SPECIALSECTION Disease INTRODUCTION Prevention CONTENTS It Takes More Than News 1468 Task Force’s Prevention Advice an Apple a Day Proves Hard to Swallow Public Health Measures in Disease Prevention AS MODELS FOR PREVENTION RESEARCH, INFECTIOUS DISEASES HAVE SET A HIGH standard. Thanks to the development and widespread distribution of vaccines and 1471 Will an Aspirin a Day Keep Cancer anti microbial drugs, we now live in a world free of smallpox, nearly free of polio, Away? Wondering How the Wonder Drug Works and with declining rates of malaria and AIDS. These victories (some still partial) have resulted in people living longer and acute infectious diseases being super- 1473 Tackling America’s Eating Habits, seded in many countries as a public health priority by long-term noncommuni- One Store at a Time cable diseases. Heart disease, metabolic disease, cancer, and respiratory disease 1476 Uncertain Verdict as Vitamin D together account for 60% of all deaths worldwide and 80% of deaths in low- and Goes On Trial middle-income countries. Global projections for dementia are particularly alarm- 1479 Chronic Disease Vaccines Need ing: By the year 2050, the disorder may affect more than 100 million people. Shot in the Arm Logic dictates that preventing these diseases is a better approach than treat- Review ing people after they have become ill. In many cases, the knowledge and tools needed for prevention appear to be in place. A number of these killer diseases 1482 Can Noncommunicable Diseases share risk factors that can be modifi ed by lifestyle changes—for example, by Be Prevented? Lessons from Studies of Populations and Individuals eliminating tobacco use, eating less processed food, and increasing physical M. Ezzati and E. Riboli activity. For certain cancers, screening tests are available that allow detection of the disease at an early stage. So why is prevention of these diseases so diffi cult Perspectives when it seems like such a good idea on paper? 1488 Preventing Alzheimer’s Disease This special section of Science highlights many of the challenges facing D. J. Selkoe researchers in noncommunicable disease prevention, a fi eld characterized by 1492 Changing Human Behavior to impassioned debates on issues as fundamental as whether the benefi ts of can- Prevent Disease: The Importance cer screening outweigh the risks, and which forms of prevention are the most of Targeting Automatic Processes cost-effective. The need for carefully designed clinical trials is a common theme T. M. Marteau et al. in discussions of potential chemopreventive agents—among them aspirin, 1495 Fetal and Early Childhood vitamin D, vaccines against chronic diseases, and β-amyloid–lowering drugs. Undernutrition, Mortality, The preventive strategies most likely to succeed on a population-wide scale are and Lifelong Health described, as are the best ways to integrate these efforts with infectious disease C. K. Lutter and R. Lutter prevention, and the far-reaching effects (some adverse) that disease prevention 1499 Double Burden of Noncommunicable efforts could have on a country’s economy. And even as medical researchers and Infectious Diseases in seek new prevention drugs and strategies, we are reminded that lifelong health Developing Countries requires proper nutrition, especially during the fi rst 1000 days of life, and that I. C. Bygbjerg effective prevention will require an understanding of why people engage in 1501 Why a Macroeconomic Perspective health-harming behaviors. Is Critical to the Prevention of One year ago this month, the United Nations convened a conference focused Noncommunicable Disease on the global reach of noncommunicable diseases, and it has since set a goal: to R. Smith reduce the probability of premature mortality from these diseases by 25% by the See also Editorial p. 1433; Policy Forum p. 1456; Science year 2025. Although the specifi cs are still a work in progress, preventive strat- Careers; Science Podcast; and videos at www.sciencemag. egies will probably play an important role. As if prevention researchers didn’t org/special/prevention. already face enough challenges, they now fi nd themselves working on a deadline. – CAROLINE ASH, PAULA KIBERSTIS, ELIOT MARSHALL, JOHN TRAVIS www.sciencemag.org SCIENCE VOL 337 21 SEPTEMBER 2012 1467 DISEASE PREVENTION www.sciencemag.org/special/prevention plained that a nerdy committee was trying to cut medical benefi ts. Radiologists claimed Task Force’s Prevention Advice that, maybe because panel members didn’t work directly with cancer patients, they Proves Hard to Swallow under valued the lifesaving power of mam- mography. Kathleen Sebelius, the HHS The current chair of the U.S. Preventive Services Task Force defends the panel’s secretary, went on television to urge calm, controversial decisions on issues such as cancer screening arguably undercutting the panel by asking women to “do what you’ve always done: … VIRGINIA MOYER, A PEDIATRICIAN WITH A Talk to your doctor” (Science, 19 February keen interest in health screening, remem- 2010, p. 936). bers what it was like to be on the U.S. Pre- The noisy response was partly the result ventive Services Task Force (USPSTF) of bad timing, says Moyer, a professor at before it became notorious—back when Baylor College of Medicine in Houston, “we felt like we were toiling in obscurity.” Texas. The task force issued its finding Created by the Department of Health and in the fall of 2009 when debate over the Human Services (HHS) 3 decades ago, the Administration’s health care reform was panel examines clinical data and decides raging and congressional election cam- whether methods of preventing disease— paigns were heating up. It was a “perfect many of them already in use—are backed storm,” agrees epidemiologist J. Michael by evidence that they’re worth using. McGinnis, an advocate of preventive health Moyer’s USPSTF term began in 2003 and care and senior scholar at the Institute of except for a 2-year break, she has served Medicine in Washington, D.C. ever since, becoming its chair in 2011. It USPSTF touched off another furor in was in 2009 that she and the rest of the task May 2012 when it voted to reject a widely force shed their relative anonymity when used method of screening for prostate can- they addressed a question many had thought cer: the blood test based on prostate-specifi c settled: Should healthy women in their 40s antigen (PSA). In this case, USPSTF found get an annual mammogram? strong negative evidence and concluded that The panel’s explosive answer: No, routine screening of healthy men should because giving such advice would do more stop. Urologists were outraged; since then, harm than good. It would lead to a huge Questioner. Pediatrician Virginia Moyer likes to their professional associations have urged number of false alarms and biopsies, the ask, “Why are we doing this?” Congress to overhaul USPSTF. They want 16-member task force found, but would do medical specialists like themselves seated little to reduce cancer deaths. clarify risks and benefi ts. Then the majority on future USPSTF panels. That’s not how the panel worded its con- voted “against” a proposed recommendation McGinnis says he expected some storms clusion, however. Using carefully honed that 40-year-olds get annual mammograms. both within and outside government when, metrics, it gave a “C” grade (meaning weak) Turmoil ensued. Congressional com- as a top HHS offi cial, he created USPSTF to evidence for benefi ts of mammography mittees grilled USPSTF members—nearly in 1984. That’s why HHS set it up as an in this age group, a topic the task force had all of whom were physicians or nurses, and independent body: “We wanted them to be studied in various ways for years. After fail- many of whom had Ph.D.s. Critics hastened totally unfettered by anything but the evi- ing to agree on a fi rst vote, USPSTF had to point out that none were cancer special- dence in the way they went about their busi- commissioned new modeling studies to ists. Advocates of mammography com- ness.” But the nature of controversy has Public Health Measures in Disease Prevention Vaccines for infectious pathogens, often mandatory, are a widespread method of preventing diseases PASS THE SALT: The mineral in a population, but organizations and countries have also tackled noncommunicable diseases with a iodine plays a crucial role in the variety of public health measures. Here are some notable examples. development of the body and the brain; a defi ciency can lead to C-ING OFF SCURVY: Scurvy, which was recognized as far back as Hippocrates, mental retardation, cretinism, and results from a defi ciency of vitamin C and prevents the formation of collagen. Scurvy thyroid problems. Switzerland was was once a common problem for those on long marine voyages, killing more than a the fi rst to introduce iodized salt, million sailors according to some estimates, but evidence slowly built that eating in 1922, as a way to help prevent citrus fruits and other foods rich in vitamin C could prevent it. Ultimately, Britain’s these conditions, and the United 1867 Merchant Shipping Act would mandate that sailors in the country’s Royal States and many other countries Navy or Merchant Navy receive a daily ration of lime or lemon juice to prevent the condition. would soon adopt the practice. CREDITS (TOP TO BOTTOM): COURTESY OF BAYLOR COLLEGE OF MEDICINE; ISTOCKPHOTO.COM OF BAYLOR CREDITS (TOP TO BOTTOM): COURTESY 1468 21 SEPTEMBER 2012 VOL 337 SCIENCE www.sciencemag.org SPECIALSECTION changed since the 1980s. When USPSTF cate fi ndings more clearly. And they agree two august bodies for these checkups and began, McGinnis says, he imagined that it on another point: A bill proposed in Con- dug up the evidence for them, and it turns would highlight the benefi ts of preventive gress this year to revamp USPSTF would out there’s not a lot of it.