Background:
Survival has significantly improved in patients with type 1 diabetes over the past 2 decades (1), shifting the health profile of this population. Obesity, once a rare condition, now affects up to 37% of U.S. adults with type 1 diabetes (2, 3). However, current studies are based on selected populations and have not considered engagement in lifestyle modification.
Objective:
To characterize the prevalence and management of overweight and obesity among adults with type 1 diabetes in the general U.S. population.
Methods:
We analyzed the National Health Interview Survey (NHIS), a nationally representative survey of the noninstitutionalized U.S. population. We combined all NHIS survey cycles for which diabetes subtype data were available (2016, 2017, 2019, 2020, and 2021). We included nonpregnant adults (aged ≥18 years) with available measures of diabetes status and body mass index (BMI) (n = 128 571). The National Center for Health Statistics Institutional Review Board approved the survey protocol. All participants provided written informed consent.
History of diagnosed diabetes was self-reported. Persons with diabetes reported diabetes type (type 1, type 2, other, or unknown) and use of insulin. We defined type 1 diabetes as a reported diagnosis of type 1 diabetes and current use of insulin (4). We classified all remaining participants with diagnosed diabetes as having type 2 diabetes.
We calculated BMI using self-reported height and weight and classified participants as having normal weight (BMI <25 kg/m2), overweight (BMI of 25 to <30 kg/m2), or obesity (BMI ≥30 kg/m2).
In select survey years (2016, 2017, and 2020), participants reported whether their physicians had recommended lifestyle changes (increasing physical activity, reducing consumption of calories or fats) over the previous year and whether they were currently engaging in these lifestyle changes.
We estimated the proportion of U.S. adults with overweight or obesity by diabetes status (no diabetes, type 1 diabetes, or type 2 diabetes). Among those with overweight or obesity, we examined the proportion who received lifestyle recommendations and engaged in lifestyle change, respectively. All analyses were conducted using Stata, version 17.0 (StataCorp). We used appropriate methods and survey weights to account for the complex survey design and generate nationally representative estimates. We calculated standard errors using Taylor series linearization.
Findings:
Participant characteristics are provided in the Table. In 2016 to 2021, 64% of adults without diabetes had overweight or obesity, compared with 62% for those with type 1 diabetes and 86% for those with type 2 diabetes (Figure, A). Among adults with overweight or obesity, those with type 1 diabetes received lifestyle recommendations more frequently than those without diabetes but less frequently than those with type 2 diabetes (Figure, C). Persons with type 1 diabetes were least likely to increase physical activity or reduce caloric intake to manage overweight or obesity. Results were similar after adjustment for age, sex, race or ethnicity, and survey year (Figure, B and D).
Table.
Characteristics of U.S. Adults, by Diabetes Status: NHIS, 2016 to 2021*
| Characteristic | No Diabetes (Unweighted n = 115 441) |
Type 1 Diabetes (Unweighted n = 733) |
Type 2 Diabetes (Unweighted n = 12 397) |
|---|---|---|---|
| Mean age, y | 46.6 ± 0.1 | 49.2 ± 0.9 | 62.8 ± 0.2 |
| Age category, % | |||
| 18-44 y | 48.6 ± 0.3 | 42.1 ± 2.4 | 9.3 ± 0.4 |
| 45-64 y | 32.6 ± 0.2 | 34.3 ± 2.1 | 43.2 ± 0.6 |
| ≥65 y | 18.8 ± 0.2 | 23.6 ± 1.8 | 47.5 ± 0.6 |
| Gender, % | |||
| Male | 49.0 ± 0.2 | 53.6 ± 2.4 | 52.2 ± 0.6 |
| Female | 51.0 ± 0.2 | 46.4 ± 2.4 | 47.8 ± 0.6 |
| Race/ethnicity, % | |||
| Hispanic | 16.0 ± 0.6 | 12.3 ± 1.8 | 18.2 ± 1.0 |
| Non-Hispanic White | 64.9 ± 0.7 | 73.7 ± 2.2 | 58.0 ± 1.1 |
| Non-Hispanic Black | 11.2 ± 0.4 | 8.9 ± 1.2 | 15.6 ± 0.7 |
| Non-Hispanic Asian | 5.9 ± 0.2 | 3.3 ± 1.0 | 5.7 ± 0.4 |
| Other non-Hispanic | 1.9 ± 0.2 | 1.8 ± 0.6 | 2.6 ± 0.4 |
| Education, % | |||
| Less than high school | 36.0 ± 0.4 | 38.6 ± 2.3 | 49.1 ± 0.7 |
| Some college | 17.7 ± 0.2 | 18.5 ± 1.7 | 17.2 ± 0.5 |
| College and above | 45.8 ± 0.4 | 42.1 ± 2.3 | 33.0 ± 0.6 |
| Missing | 0.5 ± 0.0 | 0.8 ± 0.5 | 0.8 ± 0.1 |
| Mean body mass index, kg/m2 | 27.5 ± 0.0 | 27.6 ± 0.3 | 30.9 ± 0.1 |
NHIS = National Health Interview Survey.
All estimates are based on NHIS data from 2016, 2017, 2019, 2020, and 2021. Data on overweight and obesity by diabetes status were unavailable in the 2018 NHIS. Values after the plus-minus signs are standard errors.
Figure. Prevalence of overweight and obesity among U.S. adults (A and B) and receipt of lifestyle recommendations and engagement in lifestyle changes in adults with overweight or obesity (C and D), by diabetes status: NHIS, 2016 to 2020.
Estimates of overweight and obesity were based on NHIS data from 2016, 2017, 2019, 2020, and 2021. Estimates of lifestyle recommendation and lifestyle changes were based on NHIS data from 2016, 2017, and 2020. Predictive margins (adjusted estimates) were estimated from logistic regression models that controlled for age, sex, race or ethnicity, and survey year. Error bars indicate 95% CIs. NHIS = National Health Interview Survey.
* Question text: “During the past 12 months, have you been told by a doctor or health professional to do any of the following? … Increase your physical activity or exercise?”
‡ Question text: “During the past 12 months, have you been told by a doctor or health professional to do any of the following? … Reduce the amount of fat or calories in your diet?”
‡ Question text: “Are you now doing any of the following … Increasing your physical activity or exercise?”
§ Questiontext: “Are you now doing any of the following … Reducing the amount of fat or calories in your diet?”
Discussion:
Rates of overweight and obesity in U.S. adults with type 1 diabetes are virtually identical to rates in the general adult population. Nearly two thirds of U.S. adults with type 1 diabetes have overweight or obesity. However, only about half of these patients received lifestyle recommendations from providers or engaged in lifestyle modification.
Weight management in type 1 diabetes is complicated by insulin use. Dietary and physical activity changes often require adjustments to insulin timing and dosage to prevent hypoglycemia. Evidence-based guidance on lifestyle modification in type 1 diabetes remains sparse (5), potentially contributing to low rates of recommendation by providers and low engagement by patients. Robust clinical trials are needed to understand how to promote weight management safely and effectively in persons with type 1 diabetes.
Accumulating evidence has found a high prevalence of obesity in adults with type 1 diabetes (2, 3). Our study provides the first population-based estimates for U.S. adults, extending the generalizability of these findings to the general population.
Limitations of our study include potential misclassification of diabetes and weight status due to self-report bias, imprecise estimates for adults with type 1 diabetes because of a limited sample size, and no information on weight loss medication use.
Among U.S. adults with type 1 diabetes, the burden of overweight and obesity is substantial and remains poorly managed. The development of more comprehensive clinical guidelines, with an emphasis on individualized patient education, may improve weight management in these patients.
Grant Support:
Dr. Selvin was supported by grant K24 HL152440 from the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH). Dr. Echouffo-Tcheugui was supported by NIH/NHLBI grant K23 HL153774. The funders had no role in the design or conduct of the study; collection, management, analysis, or interpretation of the data; preparation, review, or approval of the manuscript; or the decision to submit the manuscript for publication.
Footnotes
Dr. Fang and Ms. Jeon had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Disclosures: Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M22-3078.
Reproducible Research Statement: Study protocol: Not available. Statistical code: Available from Dr. Fang (mfang9@jhu.edu). Data set: Publicly available at www.cdc.gov/nchs/nhis/2021nhis.htm.
Contributor Information
Michael Fang, Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
Yein Jeon, Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
Justin B. Echouffo-Tcheugui, Division of Endocrinology, Diabetes and Metabolism, Johns Hopkins School of Medicine, Baltimore, Maryland.
Elizabeth Selvin, Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
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