Trends in the Prevalence of Lean Diabetes Among US Adults, 2015–2020

Type 2 diabetes is one of the most prevalent non-communicable diseases in the United States. By the year 2060, the number of people with diabetes in the country is expected to triple.¹ Overweight and obesity are well-established risk factor for diabetes. However, the relationship between obesity and diabetes risk is not uniform. Recent evidence suggests a high burden of diabetes even at low BMI, which is especially prevalent in race/ethnic minority populations.^2–4 This has significant implications for diabetes prevention, screening, and treatment.

In their recent article in Diabetes Care, Adesoba and Brown examined the trends in the prevalence of lean diabetes among adults in the United States from 2015 to 2020. The authors reported a nearly 18% increase in the prevalence of diabetes amongst lean individuals defined as those with a BMI <25 kg/m². There were no significant changes in the prevalence of diabetes amongst overweight/obese individuals during this same time period, thereby indicating that the largest gains in diabetes prevalence were driven by those whose BMI was considered in the normal or underweight range. The largest increases in the prevalence of diabetes among lean individuals were among Black and Hispanic adults (41.5% and 30.9%), as well as among lean women (43.2%).

This study makes the point that while overweight is a clear risk factor for diabetes, it is not the place where screening should begin, nor where prevention and treatment efforts should solely be focused. Doing so would miss a substantial proportion of individuals at risk or with diabetes and may be ineffective in reducing diabetes incidence and complications in a large proportion of the population. Adesoba and Brown used data from the Behavioral Risk Factor Surveillance System (BRFSS), which relies on self-reported diabetes and does not disaggregate Asian populations. It is possible that the prevalence of diabetes in lean individuals may have been even higher had objective measures been used as only those with a previous diabetes screening were able to self-report. Furthermore, while there were no increases in the prevalence of diabetes amongst lean Asian Americans, evidence indicates substantial heterogeneity in diabetes risk amongst Asian American subgroups,^5–7 and recent evidence points to a high burden of diabetes amongst lean Asian individuals.^8–10 Therefore, considering Asian Americans in aggregate masks meaningful differences in health and health risks amongst Asian American subgroups. In addition, Asian Americans are the least likely race/ethnic group to receive diabetes screening,¹¹ and may have a high prevalence of undiagnosed diabetes at low BMI.

The results of this paper point to several important implications. First, as mentioned in the article, the US Preventive Services Task Force for Diabetes Screening currently recommends using overweight/obesity as the main screening criteria in adults aged 35 to 70 years.¹² The US Preventive Services Task Force does recommend screening at younger ages in race/ethnic minority populations as well as at a lower BMI (≥ 23 kg/m²) in Asian Americans. However, this may not be sufficient to capture many lean people with diabetes, and screening in normal/underweight individuals in Asian as well as other race/ethnic minority populations is an important consideration. Furthermore, the majority of diabetes prevention trials have enrolled people in the overweight or obese category.^13–16 Trials on diabetes prevention in non-overweight, high-risk individuals are lacking, but are of clear importance. Lastly, given the high and increasing prevalence of diabetes amongst lean individuals, the most appropriate course of treatment should be considered. While metformin is currently the first line pharmaceutical treatment for type 2 diabetes in many settings,¹⁷ it may not be as effective among non-overweight individuals, and treatments promoting the preservation and recovery of β-cell function may be more beneficial.¹⁸

In conclusion, the paper from Adesoba and Brown highlights substantial increases in the prevalence of diabetes among lean individuals, especially in racial/ethnic minorities in the US. Given that the largest increases in diabetes prevalence are occurring in lean individuals, it is important to understand the factors other than obesity driving risk posed in this sizeable population. There are likely differences in the mechanisms, causes, effectiveness of screening, and treatment between those with obesity driven diabetes and those without. Therefore, screening practices need to be tailored to better identify high risk individuals in the absence of obesity. In addition, research focusing on more effective diabetes prevention in this population as well as studies focusing on the most beneficial forms of treatment for diabetes in lean individuals are warranted.

References

1. Lin J, Thompson TJ, Cheng YJ, et al. Projection of the future diabetes burden in the United States through 2060. Popul Health Metr. 2018;16(1):9. https://pophealthmetrics.biomedcentral.com/articles/10.1186/s12963-018-0166-4
2. Zhu Y, Sidell MA, Arterburn D, et al. 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. Diabetes Care. 2019;42(12):2211-2219. https://diabetesjournals.org/care/article/42/12/2211/36220/Racial-Ethnic-Disparities-in-the-Prevalence-of
3. Tillin T, Sattar N, Godsland IF, Hughes AD, Chaturvedi N, Forouhi NG. Ethnicity-specific obesity cut-points in the development of Type 2 diabetes - a prospective study including three ethnic groups in the United Kingdom. Diabet Med. 2015;32(2):226-234. https://onlinelibrary.wiley.com/doi/10.1111/dme.12576
4. Caleyachetty R, Barber TM, Mohammed NI, et al. Ethnicity-specific BMI cutoffs for obesity based on type 2 diabetes risk in England: a population-based cohort study [published correction appears in Lancet Diabetes Endocrinol. 2021 Jul;9(7):e2]. Lancet Diabetes Endocrinol. 2021;9(7):419-426. https://www.thelancet.com/journals/landia/article/PIIS2213-8587(21)00088-7/fulltext
5. Cheng YJ, Kanaya AM, Araneta MRG, et al. Prevalence of Diabetes by Race and Ethnicity in the United States, 2011-2016. JAMA. 2019;322(24):2389-2398. https://jamanetwork.com/journals/jama/fullarticle/2757817
6. Karter AJ, Schillinger D, Adams AS, et al. Elevated rates of diabetes in Pacific Islanders and Asian subgroups: The Diabetes Study of Northern California (DISTANCE). Diabetes Care. 2013;36(3):574-579. https://diabetesjournals.org/care/article/36/3/574/38016/Elevated-Rates-of-Diabetes-in-Pacific-Islanders
7. Gordon NP, Lin TY, Rau J, Lo JC. Aggregation of Asian-American subgroups masks meaningful differences in health and health risks among Asian ethnicities: an electronic health record based cohort study. BMC Public Health. 2019;19(1):1551. https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-019-7683-3#citeas
8. De Souza LR, Chan KT, Kobayashi K, Karasiuk A, Fuller-Thomson E. The prevalence and management of diabetes among Vietnamese Americans: A population-based survey of an understudied ethnic group. Chronic Illn. 2022;18(2):306-319. https://journals.sagepub.com/doi/10.1177/1742395320959422
9. Chan K, De Souza LR, Kobayashi K, Fuller-Thomson E. Diabetes and diabetes care among non-obese South Asian Americans: Findings from a population-based study. Diabetes Metab Syndr. 2019;13(1):96-102. https://www.sciencedirect.com/science/article/abs/pii/S1871402118303369?via%3Dihub
10. Kobayashi KM, Chan KT, Fuller-Thomson E. Diabetes among asian americans with BMI less than or equal to 23. Diabetes Metab Syndr. 2018;12(2):169-173. https://www.sciencedirect.com/science/article/abs/pii/S1871402117303922?via%3Dihub
11. Tung EL, Baig AA, Huang ES, Laiteerapong N, Chua KP. Racial and Ethnic Disparities in Diabetes Screening Between Asian Americans and Other Adults: BRFSS 2012-2014. J Gen Intern Med. 2017;32(4):423-429. https://link.springer.com/article/10.1007/s11606-016-3913-x
12. US Preventive Services Task Force, Davidson KW, Barry MJ, et al. Screening for Prediabetes and Type 2 Diabetes: US Preventive Services Task Force Recommendation Statement. JAMA. 2021;326(8):736-743. https://jamanetwork.com/journals/jama/fullarticle/2783414
13. Diabetes Prevention Program Research Group, Knowler WC, Fowler SE, et al. 10-year follow-up of diabetes incidence and weight loss in the Diabetes Prevention Program Outcomes Study [published correction appears in Lancet. 2009 Dec 19;374(9707):2054]. Lancet. 2009;374(9702):1677-1686. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(09)61457-4/fulltext
14. Ramachandran A, Snehalatha C, Mary S, et al. The Indian Diabetes Prevention Programme shows that lifestyle modification and metformin prevent type 2 diabetes in Asian Indian subjects with impaired glucose tolerance (IDPP-1). Diabetologia. 2006;49(2):289-297.https://link.springer.com/article/10.1007/s00125-005-0097-z
15. Lindström J, Louheranta A, Mannelin M, et al. The Finnish Diabetes Prevention Study (DPS): Lifestyle intervention and 3-year results on diet and physical activity. Diabetes Care. 2003;26(12):3230-3236. https://diabetesjournals.org/care/article/26/12/3230/21849/The-Finnish-Diabetes-Prevention-Study-DPS
16. Pan XR, Li GW, Hu YH, et al. Effects of diet and exercise in preventing NIDDM in people with impaired glucose tolerance. The Da Qing IGT and Diabetes Study. Diabetes Care. 1997;20(4):537-544. https://diabetesjournals.org/care/article/20/4/537/22408/Effects-of-Diet-and-Exercise-in-Preventing-NIDDM
17. Bailey CJ. Metformin: historical overview. Diabetologia. 2017;60(9):1566-1576. https://link.springer.com/article/10.1007/s00125-017-4318-z
18. van Raalte DH, Verchere CB. Improving glycaemic control in type 2 diabetes: Stimulate insulin secretion or provide beta-cell rest?. Diabetes Obes Metab. 2017;19(9):1205-1213. https://dom-pubs.onlinelibrary.wiley.com/doi/10.1111/dom.12935