Racial/Ethnic Disparities in the Prevalence of Diabetes and Prediabetes by BMI: Patient Outcomes Research To Advance Learning (PORTAL) Multisite Cohort of Adults in the U.S.

Abstract

To examine racial/ethnic disparities in the prevalence of diabetes and prediabetes by BMI category. RESEARCH DESIGN AND METHODS In a consortium of three U.S. integrated health care systems, 4,906,238 individuals aged ‡20 years during 2012-2013 were included. Diabetes and prediabetes were ascertained by diagnosis and laboratory results; antihyperglycemic medications were also included for diabetes ascertainment. RESULTS The age-standardized diabetes and prediabetes prevalence estimates were 15.9% and 33.4%, respectively. Diabetes but not prediabetes prevalence increased across BMI categories among all racial/ethnic groups (P for trend < 0.001). Racial/ethnic minorities reached a given diabetes prevalence at lower BMIs than whites; Hawaiians/Pacific Islanders and Asians had a diabetes prevalence of 24.6% (95% CI 24.1-25.2%) in overweight and 26.5% (26.3-26.8%) in obese class 1, whereas whites had a prevalence of 23.7% (23.5-23.8%) in obese class 2. The agestandardized prediabetes prevalence estimates in overweight among Hispanics (35.6% [35.4-35.7%]), Asians (38.1% [38.0-38.3%]), and Hawaiians/Pacific Islanders (37.5% [36.9-38.2%]) were similar to those in obese class 4 among whites (35.3% [34.5-36.0%]), blacks (36.8% [35.5-38.2%]), and American Indians/Alaskan Natives (34.2% [29.6-38.8%]). In adjusted models, the strength of association between BMI and diabetes was highest among whites (relative risk comparing obese class 4 with normal weight 7.64 [95% CI 7.50-7.79]) and lowest among blacks (3.16 [3.05-3.27]). The association between BMI and prediabetes was less pronounced. CONCLUSIONS Racial/ethnic minorities had a higher burden of diabetes and prediabetes at lower BMIs than whites, suggesting the role of factors other than obesity in racial/ethnic disparities in diabetes and prediabetes risk and highlighting the need for tailored screening and prevention strategies.

Diabetes in Normal-Weight Individuals: High Susceptibility in Nonwhite Populations

“…This study by Zhu et al (5) has several notable strengths. It included a large cohort of 4.9 million adults that was racially/ethnically, geographically, and socioeconomically diverse.…”

“…In their article in this issue of Diabetes Care, Zhu et al (5) examined racial/ethnic disparities in the prevalence of diabetes by BMI category in a large, racially/ ethnically and geographically diverse cohort of 4.9 million adults. Individuals enrolled in the cohort were members of three integrated health care systems in the U.S. in the years 2012-2013 and were from six racial/ethnic groups including white, black, Hispanic, Asian, Hawaiian/ Pacific Islander, and American Indian/ Alaskan Native.…”

Prevalence of diagnosed diabetes in American Indian and Alaska Native adults, 2006–2017

“…8 Zhu et al estimated prevalence for AI/AN adults aged 20 years and older at 19.6% (95% CI, 19.1% to 20.0%) in 2012-2013. 9 However, this was based on several regional samples of non-Hispanic AI/AN adults that are not nationally representative. In contrast to these two studies, ours is based on a large number of AI/AN adults aged 18 years and older from across the USA, including those of mixed racial/ethnic heritage, who met IHS eligibility criteria.…”

“…Our study included over one million AI/AN adults who received care from facilities in 35 states. By comparison, diabetes prevalence estimates for AI/AN adults derived from regional studies are not nationally representative 9 and those from national surveys are based on very small numbers of AI/AN participants. 1 8 As such, the CDC National Diabetes Statistics Report uses IHS diabetes prevalence estimates for representation of AI/AN people as a racial group.…”

“…8 Other studies have used samples that may not be representative of AI/AN people nationally. 9 A large and nationally representative source of data 2 BMJ Open Diab Res Care 2020;8:e001218. doi:10.1136/bmjdrc-2020-001218…”