Jump in US Gestational Diabetes Rates Seen Across All Racial, Age Groups

Between 2011 and 2019, rates of gestational diabetes (GD) among individuals with a singleton first live birth increased across all race and ethnicity subgroups in the United States, according to new research published in JAMA.¹

In particular, investigators found the age-standardized rate of GD increased from 47.6 to 63.5 per 1000 live births during this time window, while Asian Indian individuals were found to have the highest GD rate of 129.1 per 1000 live births.

Defined as the onset of glucose intolerance during pregnancy, GD is common but associated with adverse short- and long-term risks for both women and their offspring. These can include increased risks of developing future diabetes and cardiovascular disease among mothers.

“In offspring, fetal exposure to gestational diabetes in utero has been linked to macrosomia and adiposity in newborns and impaired glucose tolerance and obesity in childhood, thereby increasing risks for adverse cardiometabolic outcomes for offspring across the lifespan,” authors explained.

Using deidentified data from the National Center for Health Statistics, researchers analyzed annual rates of GD to inform equitable strategies for population-level management and prevention.

Any individual younger than 15 or older than 44 was excluded from the final analyses, while records from nonsingleton births (eg, twins) and non-US residents were also excluded. Information regarding maternal demographic and prenatal characteristics was also collected.

Primary analyses categorized individuals into the 4 largest race and ethnicity groups (Hispanic/Latina, non-Hispanic Asian/Pacific Islander, non-Hispanic Black, and non-Hispanic White) and secondary analyses analyzed GD rates among smaller subgroups.

“Among the 12,610,235 included individuals (mean [SD] age, 26.3 [5.8] years), the overall age-standardized gestational diabetes rate significantly increased from 47.6 (95% CI, 47.1-48) to 63.5 (95% CI, 63.1-64) per 1000 live births from 2011 to 2019, a mean annual percent change of 3.7% (95% CI, 2.8%-4.6%) per year,” researchers found.

Of the over 12 million participants:

• 21% were Hispanic/Latina (2019 GD rate, 66.6 [95% CI, 65.6-67.7]; rate ratio [RR], 1.15 [95% CI, 1.13-1.18])
• 8% were non-Hispanic Asian/Pacific Islander (2019 GD rate, 102.7 [95% CI, 100.7-104.7]; RR, 1.78 [95% CI, 1.74-1.82])
• 14% were non-Hispanic Black (2019 GD rate, 55.7 [95% CI, 54.5-57.0]; RR, 0.97 [95% CI, 0.94-0.99])
• 56% were non-Hispanic White (2019 GD rate, 57.7 [95% CI, 57.2-58.3]

Analyses also revealed:

• GD rates were highest in Asian Indian participants (2019 GD rate, 129.1 [95% CI, 100.7-104.7]; RR, 2.24 [95% CI, 2.15-2.33])
• Among Hispanic/Latina participants, GD rates were highest among Puerto Rican individuals (2019 GD rate, 75.8 [95% CI, 71.8-79.9]; RR, 1.31 [95% CI, 1.24-1.39])
• GD rates increased among all race and ethnicity subgroups and across all age groups
• Trends showed that rates of pregestational diabetes increased over time in most subgroups

The majority of individuals included had completed a high school education and had insurance coverage, while Hispanic/Latina individuals predominately reported having Medicaid coverage.

For non-Hispanic Black individuals, rates of GD increased from 49 to 55.7 per 1000 live births during the study window. Japanese individuals exhibited the fastest relative increase in absolute GD rates, although they constituted the lowest absolute GD rates throughout most of the study period, authors wrote.

As GD rate increases took place alongside increases in prevalence of obesity, physical inactivity, and poor diet quality, these factors may have played a role in the trends observed. Differences in GD risk factors and exposure to social determinants of health may have also contributed to the heterogenous trends, researchers hypothesized.

“Specifically, Hispanic/Latina individuals at first live birth had a relatively higher BMI [body mass index] and lower educational attainment than non-Hispanic White individuals. In contrast, Asian Indian individuals at first live birth had the highest rates of gestational diabetes despite lower BMI levels and higher educational attainment,” they explained.

Higher cardiometabolic risk and dysregulated visceral fat deposition at lower BMI could have also impacted trends.

In addition, rates of GD “were significantly lower, but pregestational diabetes rates were significantly higher, in non-Hispanic Black individuals compared with non-Hispanic White individuals, indicating that more non-Hispanic Black individuals had diabetes when becoming pregnant so were not ‘at risk’ for gestational diabetes.”

More research is needed to understand long-term cardiometabolic outcomes of GD in subgroups as these individuals are less represented in previous research.

To help address these disparities, The American College of Obstetrics and Gynecologists recommends individuals with risk factors for GD be considered for earlier GD screening prior to the universal second trimester screening.

The current analysis was only conducted among individuals with singleton first live births. “Because multiparity may be a risk factor for gestational diabetes, focusing on individuals at first live birth may actually underestimate total gestational diabetes rates,” authors cautioned. Analyses also excluded individuals who experienced fetal deaths, and an option for identifying as Southeast Asian of Middle Eastern/ North African groups was not available, marking limitations to the study.

According to authors of an accompanying editorial,² many of the race-associated determinants of health documented in this and previous studies can be linked to systemic racism.

“Systemic racism (racial bias embedded in institutions, structures of power, and policies across society) limits the access of racial and ethnic minority individuals to resources, including housing, healthy food, living environments conducive to physical activity, education, and high-quality health care,” authors wrote, adding, “the experience of discrimination may influence diabetes risk through a variety of biological mechanisms.”

The authors argued rectifying these inequities necessitates addressing root causes, although more research is needed to discern the best methods for promoting health equity in diabetes-related pregnancy outcomes.

“Identification of gestational diabetes, by revealing a predisposition to glucose intolerance in a young adult population, represents an opportunity for diabetes prevention that could be capitalized upon to address increasing diabetes rates in the general population,” they concluded.

Overall, the findings “reinforce that it is time to get serious about curbing increasing rates of gestational diabetes, particularly in pregnant people from racial and ethnic minority populations.”

References

1. Shah NS, Wang MC, Freaney PM, et al. Trends in gestational diabetes at first live birth by race and ethnicity in the US, 2011-2019. JAMA. Published online August 17, 2021. doi:10.1001/jama.2021.7217

2. Powe CE and Carter EB. Racial and ethnic differences in gestational diabetes time to get serious. JAMA. Published online August 17, 2021. doi:10.1001/jama.2021.7520