For the past few years, George King, the director of research at Boston’s Joslin Diabetes Center, has been following a medical mystery that has flown under the public-health radar—even, he told me, among most other diabetes experts. He and his colleagues have been alarmed by the skyrocketing rates of gestational diabetes they’ve seen among Chinese American populations, which mirror a similar phenomenon in mainland China and Taiwan.
For years, gestational diabetes has been ticking upward in people of Asian descent—both in countries in Asia and in highly multicultural nations such as the United States. In general, those rises have tracked with increases in type 2 diabetes, a condition with similar risk factors. But “one group is an outlier,” King said. In recent years, gestational diabetes has climbed among people of Chinese descent at a rate that appears to outpace the rise in diabetes in that population, and “no one seems to know why,” he said.
The data supporting this discrepancy are still just emerging, King and his colleagues told me, and they hope to collect more of the evidence themselves. By this fall, they plan to apply for federal funding to study an intervention they’d like to test in the greater Boston area to reduce rates of gestational diabetes among Asian Americans more broadly. If, along the way, they collect evidence that helps crack the mystery of whether Chinese Americans are at particularly high risk, that information could help clarify risk factors about gestational diabetes in general or sharpen their intervention further—perhaps allowing them to tailor it even better to some of the communities that need the most help.
Gestational diabetes is most simply understood as a form of type 2 diabetes that first crops up during pregnancy. “Pregnancy is a pressure test for your body,” Tam Nguyen, a chronic-disease researcher at Boston College, told me—and it can catalyze health issues that might not have plagued people otherwise. Roughly half of people with gestational diabetes will go on to develop type 2 diabetes; the child, too, ends up at higher risk of metabolic issues.
Asian Americans develop gestational diabetes at notably high rates, but even among communities of Asian descent, that risk is little known, experts told me. “I think it’s totally invisible,” perhaps in part because people in those communities tend to develop diabetes at lower BMIs than white populations do, Nguyen said. Compared with other racial and ethnic populations, many people of Asian heritage tend to have less lean-muscle mass and carry more fat centrally, around their vital organs—a type of fat linked to many metabolic issues. That tricky combination leaves many cases undiagnosed early on and many individuals unaware of their own elevated risk.
That can be especially dangerous during pregnancy: Left unmanaged, gestational diabetes ups the chances of preeclampsia, premature birth, high birth weight, and stillbirth. At a meeting at Joslin earlier this month that I attended, Atif Adam, a research fellow at the center, described gestational diabetes among Asian American populations as “the largest undocumented disparity in maternal health.”
Experts on this population have also long recognized that the umbrella of “Asian” encompasses many different groups with different genetics, physiologies, lifestyles, and cultural preferences—and, as a result, different vulnerabilities to disease, including gestational diabetes. South and Southeast Asians, for instance, tend to develop the condition at particularly high rates. The data on where people of Chinese descent may fall on this broad spectrum are a bit mixed, but King and Adam told me that at least a handful of recent reports—especially out of China and nearby Taiwan—suggest that rates of gestational diabetes in this population have risen markedly over time. And the pattern of growth, Adam said, “seems to be different from other ethnicities.”
The exact reason for the rise has eluded researchers, though they’ve raised plenty of possibilities. In China, for instance, some experts think that at least part of the explanation is the implementation of the two-child policy, which bumped up the average maternal age at birth—a key risk factor for gestational diabetes. But that can’t account for comparable rises in nations that haven’t adopted such policies; average maternal age has also risen in countries around the world without tugging up gestational diabetes in the same way. King, for one, suspects that nutrition may be playing a particularly big role in Chinese communities, where Westernized menu items have made up a big part of the diet in recent years, including in China. Nguyen, though, said she thinks that researchers studying any emerging trends in gestational diabetes among Asian populations have to consider several variables at once. Subtle factors such as toxin exposure and the composition of the gut microbiome could contribute; so, too, could social stressors such as racism. (One recent study suggested, for instance, that the intense anti-Asian sentiment connected to COVID-19, which President Trump described as being caused by the “China virus,” could help explain recent rises in gestational diabetes among Asian groups, including people of Chinese descent.)
Nailing down this trend and any reasons for it won’t be easy. Researchers don’t consistently disaggregate “Asian” populations into the many possible subgroups, and even when they do, different researchers have different approaches to categorizing people. That makes it challenging to tease apart problems that might be plaguing specific communities. And although several of the Boston-based researchers I spoke with are collecting some of their own population-specific evidence from local health centers, they aren’t sure when data collection might improve more generally. A few years ago, the state of Massachusetts announced that it would begin collecting more detailed demographic data on racial and ethnic groups, including within the Asian community. But the implementation of that plan has been slow, and some locals have expressed discomfort with the idea of submitting more identifying information, Nguyen said. On the national scale, the U.S.’s National Health and Nutrition Examination Survey, a vital source of data on diabetes, has been purposefully oversampling Asian Americans since 2011, which has allowed researchers to dig deeper into trends in specific subpopulations. But last fall, the Trump administration fired core staff from the CDC division that runs the survey, leaving its future uncertain.
Even without more definitive data, Adam said, he and his colleagues are eager to design an intervention that could help any Asian group lower its gestational-diabetes risk, or better manage the condition once it arises. In broad strokes, the advice would mirror what the general population is told in the U.S. about avoiding and dealing with the condition: Eat well, exercise, avoid excessive weight gain. But it would be delivered more consistently, across health-care settings, and would be better tailored to certain groups’ cultural preferences. For many families deeply embedded in Asian food culture, “it’s difficult to be told to reduce white-rice intake,” Nguyen pointed out; some people might also benefit from a discussion about incorporating familiar types of physical activity, such as walking and tai chi, into their routine, rather than vaguer cautions to work out more.
In the meantime, the researchers will keep observing what trends they can, to see whether certain Asian subgroups might warrant special attention. They feel confident that they know enough about what works and how to deliver it to make some impact. But any specific vulnerabilities are still worth narrowing in on, so that no vulnerable community risks being lost to an aggregated trend.
