About half of the adult U.S. population will have obesity and about a quarter will have severe obesity by 2030, according to a new study led by Harvard T.H. Chan School of Public Health.
photo credit: Harvard T.H. Chan
The study also predicts that in 29 states, more than half of the population will have obesity, and all states will have a prevalence of obesity higher than 35%. The study’s researchers estimate that, currently, 40% of American adults have obesity and 18% have severe obesity.
The study was published in the December 19, 2019 issue of the New England Journal of Medicine.
The researchers said the predictions are troubling because the health and economic effects of obesity and severe obesity take a toll on several aspects of society. “Obesity, and especially severe obesity, are associated with increased rates of chronic disease and medical spending, and have negative consequences for life expectancy,” said Steven Gortmaker, professor of the practice of health sociology at Harvard Chan School and senior author of the study.
For the study, the researchers used self-reported body mass index (BMI) data from more than 6.2 million adults who participated in the Behavioral Risk Factor Surveillance System Survey (BRFSS) between 1993 and 2016. Body mass index (BMI) is calculated by dividing a person’s weight in kilograms by the square of their height in meters. Obesity is defined as a BMI of 30 or higher, and severe obesity is a BMI of 35 or higher.
Self-reported BMIs are frequently biased, so the researchers used novel statistical methods to correct for this bias.
The large amount of data collected in the BRFSS allowed the researchers to drill down for obesity rates for specific states, income levels, and subpopulations.
“The high projected prevalence of severe obesity among low-income adults has substantial implications for future Medicaid costs,” said lead author Zachary Ward, programmer/analyst at Harvard Chan School’s Center for Health Decision Science. “In addition, the effect of weight stigma could have far-reaching implications for socioeconomic disparities as severe obesity becomes the most common BMI category among low-income adults in nearly every state.”
Ward and his co-authors said that the study could help inform state policy makers. For example, previous research suggests that sugar-sweetened beverage taxes have been an effective and cost-effective intervention for curtailing the rise in obesity rates. “Prevention is going to be key to better managing this epidemic,” said Ward.
A team of Boston-area researchers, including Harvard T.H. Chan School of Public Health’s Shruthi Mahalingaiah, are undertaking a new research project to address women’s reproductive health challenges.
The project, supported by a $1.2 million four-year grant from the National Science Foundation’s Smart and Connected Health program, will use artificial intelligence and machine learning to develop personalized reproductive and fertility predictions, as well as personalized treatments for fertility issues.
The team brings together experts from various fields, including electrical and computer engineering, public health, and medicine. Boston University College of Engineering Professor Ioannis Paschalidis is the principal investigator (PI) of the project. Mahalingaiah, assistant professor of environmental reproductive and women’s health at Harvard Chan School, is co-PI.
“Collaboration for improving discovery and improving care for women across the lifecourse is critically important,” Mahalingaiah said in an October 28, 2019 Boston University Center for Information & Systems Engineering article. “Merged datasets including self reporting, lifestyle, and exposures, clinical-grade data, and data collected from wearable devices will provide personalized insights so that women can be empowered to understand information on the health of their bodies and make the best choices for their health and futures.”
Nearly half of all childhood cancers are not being diagnosed globally, according to a new modeling study led by Harvard T.H. Chan School of Public Health.
A mother and baby in Burkina Faso.
The study found that, in 2015, there were 397,000 cases of childhood cancer worldwide, but only 224,000 were diagnosed. And if health systems around the world don’t improve, the researchers estimate that 2.9 million out of 6.7 million projected childhood cancer cases—43%—will be missed between 2015 and 2030.
The study was published February 26, 2019 in Lancet Oncology. Watch a video with the authors.
“Our model suggests that nearly one in two children with cancer are never diagnosed and may die untreated,” said lead author Zachary Ward, a doctoral student in health policy at Harvard Chan School. “This new model provides specific estimates of childhood cancer that have been lacking.”
Accurate estimates of childhood cancer incidence are needed to inform health policies, but many countries don’t have cancer registries that quantify this incidence. In addition, existing registries may underestimate the true incidence of childhood cancer, according to the authors.
In the new study, researchers developed a model to simulate childhood cancer incidence for 200 countries and territories worldwide. The model included data from cancer registries in countries where they exist. It also took into account trends in population growth and urbanization, geographical variation in cancer incidence, and health system barriers to access and referral that contribute to underdiagnosis.
The prevalence of undiagnosed cancer cases varied widely across regions, from just 3% in western Europe and North America to 57% in western Africa, the study estimated. In south Asia, 49% of cases were undiagnosed. The researchers said that 92% of new cases of cancer are occurring in low- and middle-income countries, a higher proportion than previously thought.
The authors hope that their findings will help guide health systems in setting new policies to improve diagnosis and management of childhood cancers.
“Health systems in low-income and middle-income countries are clearly failing to meet the needs of children with cancer,” said Rifat Atun, professor of global health systems and senior author of the study. “Universal health coverage, a target of United Nations Sustainable Development Goals, must include cancer in children as a priority to prevent needless deaths.”
Funding for the study came from Boston Children’s Hospital, Dana-Farber Cancer Institute, Harvard T.H. Chan School of Public Health, Harvard Medical School, the National Cancer Institute, SickKids, St. Jude Children’s Research Hospital, and the Union for International Cancer Control.
Mosquitoes that landed on surfaces coated with the antimalarial compound atovaquone were completely blocked from developing Plasmodium falciparum (P. falciparum), the parasite that causes malaria, according to new research led by Harvard T.H. Chan School of Public Health.
The study showed that atovaquone—an active ingredient in medication that’s commonly used in humans to prevent and treat malaria—can be absorbed through mosquitoes’ tarsi (legs) and prevents the insects from developing and spreading the parasite. The findings indicate that treating bed nets with atovaquone or similar compounds would be an effective way to reduce the burden of malaria while significantly mitigating the growing problem of insecticide resistance.
“Mosquitoes are amazingly resilient organisms that have developed resistance against every insecticide that has been used to kill them. By eliminating malaria parasites within the mosquito rather than killing the mosquito itself, we can circumvent this resistance and effectively prevent malaria transmission,” said Flaminia Catteruccia, professor of immunology and infectious diseases. “Ultimately, the use of antimalarials on mosquito nets could help eliminate this devastating disease. It’s a simple but innovative idea that’s safe for people who use mosquito nets and friendly to the environment.”
The study was published online in Nature on February 27, 2019.
Malaria poses a risk to nearly half of the world’s population. Annually, more than 200 million people become sick with malaria and more than 400,000 people die from it. During the past 20 years, bed nets treated with long-lasting insecticides that kill mosquitoes have significantly reduced the global malaria burden. It’s estimated that such bed nets are responsible for 68% of all malaria cases averted since 2000. Recent years, however, have seen a surge in mosquitoes that are resistant to the most commonly used insecticides. In some malaria hot spots, there is near total resistance to pyrethroids, one of the key groups of insecticides currently in use. The waning effectiveness of insecticides is a public health emergency that threatens to undo decades of progress toward controlling malaria and highlights the urgent need to develop new approaches to stop the spread of the disease.
For this study, the researchers reasoned that they could introduce antimalarial compounds to Anopheles mosquitoes in a way that’s similar to a mosquito making contact with insecticides on a bed net. Rather than kill the mosquitoes, the aim was to give them a prophylactic treatment so that they could not develop and transmit the malaria-causing parasite.
To test the approach, they coated glass surfaces with atovaquone and covered them with a plastic cup. Female mosquitoes were then introduced into the cup. Prior to or immediately after the mosquitoes made contact with the atovaquone-coated glass, the researchers infected them with P. falciparum. Over the course of the study, mosquitoes were exposed to different concentrations of atovaquone and were kept in the cups for different amount of times.
The study found that P. falciparum development was completely blocked at relatively low concentrations of atovaquone (100 μmol per m2) and when mosquitoes were exposed for just 6 minutes, which is comparable to the time wild mosquitoes spend on insecticide-treated bed nets. The researchers had similar success when using other compounds similar to atovaquone. While atovaquone effectively killed parasites, it had no effects on mosquito lifespan or reproduction.
“When we put these data into a mathematical model using real-world data on insecticide resistance, bed net coverage and malaria prevalence, it showed that supplementing conventional bed nets with a compound like atovaquone could appreciably reduce malaria transmission under almost any conditions we had data for in Africa,” said Douglas Paton, research fellow and lead author of the paper. “What got us really excited is that it also showed that this new intervention would have the greatest impact in areas with the highest levels of mosquito insecticide resistance.”
Popular electronic cigarette (e-cigarette) products sold in the U.S. were contaminated with bacterial and fungal toxins, according to new research from Harvard T.H. Chan School of Public Health.
The study, which examined 75 popular e-cigarette products—cartridges (single use) and e-liquids (refillable material)—found that 23% contained traces of endotoxin, a microbial agent found on Gram-negative bacteria, and that 81% contained traces of glucan, which is found in the cell walls of most fungi. Exposure to these microbial toxins has been associated with myriad health problems in humans, including asthma, reduced lung function, and inflammation.
“Airborne Gram-negative bacterial endotoxin and fungal-derived glucans have been shown to cause acute and chronic respiratory effects in occupational and environmental settings,” said David Christiani, Elkan Blout Professor of Environmental Genetics and senior author of the study. “Finding these toxins in e-cigarette products adds to the growing concerns about the potential for adverse respiratory effects in users.”
The study was published online in Environmental Health Perspectives on April 24, 2019.
The use of e-cigarettes has been steadily climbing in recent years, especially among high school and middle school students. It’s estimated that more than three million high school students used e-cigarettes in 2018, up from 220,000 in 2011. Previous research from Harvard Chan School has shown that chemicals linked with severe respiratory disease are found in common e-cigarette flavors. Moreover, research by HSPH investigators conducted over many decades has shown chronic lung impairment in populations exposed to airborne biological contaminants. Yet, according to the authors, no research exists on the potential contamination of e-cigarettes with microbes or microbial toxins.
For this study, the researchers selected 37 e-cigarette cartridges, sometimes referred to as “cigalikes,” and 38 e-liquid products, which can be used to refill certain cartridges, from the ten top-selling U.S. brands. The products were classified into four different flavor categories: tobacco, menthol, fruit, and other. All of the products were then screened for the presence of endotoxin and glucan.
The findings showed that 17 of 75 products (23%) contained detectable concentrations of endotoxin and that 61 of 75 products (81%) contained detectable concentrations of glucan. Further analysis showed that cartridge samples had 3.2 times higher concentrations of glucan than the e-liquid samples. Glucan concentrations were also significantly higher in tobacco- and menthol-flavored products than in fruit-flavored products. The study also found that endotoxin concentrations were higher in fruit-flavored products, indicating that raw materials used in the production of flavors might be a source of microbial contamination.
The researchers noted that the contamination of the products could have occurred at any point during the production of the ingredients or of the finished e-cigarette product. They hypothesized that cotton wicks used in e-cigarette cartridges may be one potential source of contamination, as both endotoxin and glucan are known contaminants of cotton fibers.
“In addition to inhaling harmful chemicals, e-cig users could also be exposed to biological contaminants like endotoxin and glucan,” said Mi-Sun Lee, research fellow and lead author of the paper. “These new findings should be considered when developing regulatory policies for e-cigarettes.”
Some of the most important medications doctors have at their disposal have been rendered ineffective by parasites, viruses, and bacteria that have evolved resistance against them, and the problem is poised to get worse.
Drug-resistant strains of gonorrhea, salmonella, Escherichia coli (E. coli) and many other disease-causing agents are flourishing around the world, and the consequences are disastrous—at least 700,000 people die globally as a result of antimicrobial resistance (AMR) annually, according to a 2016 review on antimicrobial resistance commissioned by former UK Prime Minister David Cameron.
It’s a perilous situation, but several new studies from researchers at Harvard T.H. Chan School of Public Health indicate that an important tool in the fight against AMR already exists: vaccines.
The Proceedings of the National Academy of Sciences (PNAS) recently devoted a special feature section to examine the role vaccines can play in stemming the tide of AMR. In general terms, vaccinations can help lessen the burden of AMR in two ways: First, they can protect against the direct transmission of drug-resistant infections. Second, they can lessen the chances of someone getting sick, which in turn reduces the likelihood that he or she will be prescribed antibiotics or other medications. The fewer medications someone takes, the less likely it is that microbes will evolve resistance to the drugs.
“Despite the increased attention paid to vaccination as a response to AMR in recent years, it remains underemphasized in many cases,” said David Bloom, Clarence James Gamble Professor of Economics and Demography, who co-authored an overview articlefor the PNAS feature. “Vaccination potentially confers considerable value with regard to its ability to slow the development of antimicrobial resistance and mitigate its worst effects.”
As Bloom notes, AMR is not a new problem. Bacteria have been evolving resistance to antibiotics since the first doses of penicillin were administered back in the 1940s. In the past few decades, though, the burden of AMR has skyrocketed and there’s emerging evidence that some drug-resistant bugs are more aggressive or transmissible than their drug-susceptible counterparts.
Among the many challenges is that any use of antimicrobials, including common antibiotics, drives the evolution of resistance, even if the drugs are being used appropriately, Bloom said. Efforts to curb AMR have mostly focused on developing new antibiotics and other drugs. That’s certainly part of the solution, he said, but developing new drugs is a slow, costly process and it’s only a matter of time before the targeted parasites or bacteria begin developing resistance to the new drugs.
Vaccines are appealing because they don’t just protect individuals against germs, they protect entire communities through “herd immunity” (the more people that are vaccinated, the harder it is for germs to spread). For instance, Bloom points to drops in drug-resistant pneumococcal disease in areas where pneumococcal conjugate vaccines have been widely administered. There is also evidence showing that pathogens are much less likely to develop resistance to vaccines than they are to antimicrobial treatment—making vaccines an important first-line defense against AMR.
Promising as this sounds, there’s still much to learn about vaccines and AMR, both on the biological side and on the implementation side. To that end, PNAS featured a paperled by JP Sevilla, research associate at Harvard Chan School, that discussed the need to create a framework to assess the economic value of vaccines with regard to their impact on AMR.
Based on what’s known now, it appears that vaccinations offer significant value by addressing AMR and its associated social and economic challenges. Failing to account for AMR in economic assessments of vaccinations could mean that we are undervaluing vaccination programs and consequently underinvesting in vaccine R&D and uptake.
“Addressing AMR doesn’t require making fundamental changes to already well-developed frameworks for economically evaluating vaccines. There’s a causal chain flowing from vaccination, to its health impacts, and the economic consequences of those impacts. The economic elements of the chain—measuring vaccination costs and the economic consequences of health impacts—are the easier part,” Sevilla said. “The hardest link and highest research priority is the non-economic middle: tracing through the causal impacts of vaccination on susceptible and resistant disease.”
Another PNAS paper, co-authored by Chan School’s Marc Lipsitch, professor of epidemiology, examined how vaccines may help protect the microbiome, the collection of trillions of microorganisms throughout the body. The study noted that the microbiome appears to play an important role in helping humans mount effective immune responses to pathogens. But antimicrobials, which are often broad spectrum and don’t just target the organism that’s causing illness, could alter the microbiome and make it less effective when it comes to spurring the immune system into action.
Further exploring the interplay between vaccines and the microbiome, a paper co-authored by Harvard Chan School PhD student Christine Tedijanto, showed the extent to which bacteria that are commonly found in the microbiome are exposed to antibiotics even when they are not the target of the medication. In other words, if a patient is prescribed antibiotics for a case of pneumonia caused by Streptococcus pneumoniae (S. pneumoniae), it’s likely the antibiotics will also affect E. Coli and other naturally occurring bacteria in the person’s microbiome that are not making the person sick. This in turn increases the likelihood that those untargeted bacteria may become resistant to the antibiotics.
Tedijanto’s study showed that vaccines can help mitigate this effect. She found that pneumococcal conjugate vaccination programs, which provide protection against S. pneumoniae infection, significantly reduce the amount of antibiotics E. Coli and Staphylococcus aureus (S. aureus) are exposed to even though they’re not directly targeted by the vaccine.
While there is significant potential for vaccines to help quell the burden of AMR, Bloom said that a robust and integrated set of solutions is needed, including the development of new vaccines, new antibiotics and other medications, as well as buy-in from policymakers, the global health community, and the public at large.
There is strong evidence that a plant-based diet is the optimal diet for living a long and healthy life, according to Harvard T.H. Chan School of Public Health nutrition expert Walter Willett.
In a January 7, 2019 interview on the NPR show “1A,” Willett, professor of epidemiology and nutrition, said that it’s not necessary to be 100% vegan in order to reap the benefits of a plant-based diet, which has been linked with lower risk of type 2 diabetes, heart disease, and overall mortality. Diets with modest amounts of dairy and fish, and even some poultry and meat, can also be healthy, as long as people steer clear of refined starches and sugar and focus on vegetables, fruits, nuts, seeds, and whole grains.
Willett also said that veganism is good for the planet. That’s because cattle grazing generates massive amounts of methane and carbon dioxide, both of which are potent greenhouse gases that contribute to climate change.
“I think if we really care about the world our children and grandchildren will inherit, we do need to shift toward [a vegan diet],” said Willett. “And the good news is that it’s not just our planet that will be more healthy, but we will be more healthy as well.”
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