Analyzing the Significance of Minority Representation in Clinical Studies

Minority representation in clinical studies often becomes overlooked, which can inhibit attributable research and heightened risk awareness within these subpopulations. In a novel study focusing on the association of sleep duration and obesity in African Americans, data derived from the Jackson Heart Study revealed an increased rate of participants with overweight and obesity and exhibited suboptimal sleep duration, according to research published this week in The Journal of the American Osteopathic Association.¹

Prior studies have exhibited sleep duration’s influence on obesity through causes such as unregulated appetite, excessive eating while awake, and decreased energy expenditure. However, the study authors noted that these studies have not focused primarily on minority groups and whether certain race/ethnicity groups may be more susceptible to becoming overweight or obese.

Researchers used multivariate analysis to examine associations among sleep duration, sleep quality, general obesity (measured through body mass index [BMI]), and abdominal obesity (measured through waist circumference [WC]) in 3778 participants, 1363 men and 2415 women. Measurements were derived from clinic visits in which sleep habits of participants were recorded by a sleep history questionnaire, with additional recordings of BMI and WC in African Americans.

Data analysis from the study group revealed a significant 87.8% (3317 participants) were overweight and 56.9% (2149 participants) were obese:

• Mean (SD) BMI was 32.1 (7.2) kg/m² and mean WC was 103.3 (16.0) cm
• Mean sleep duration (men = 6.3 (1.4) hours; women = 6.4 (1.5) hours)

The measurements of sleep duration for men and women slightly above 6 hours reveal a definite shortage when compared with the National Sleep Foundation’s recommendation of 7 to 9 hours of sleep for adults aged 18-64 years. The high rate of participants with overweight and obesity is additionally troubling as a September study published in the journal Diabetes Care,² revealed that minorities are more likely to have diabetes or prediabetes at lower weights when compared with whites:

• Diabetes prevalence at normal BMI for whites: 5%
• Prevalence higher in Hawaiians/Pacific Islanders (18%), African Americans (13.5%), Hispanics (12.9%), Asians (10.1%), American Indians/Alaskan Natives (9.6%)

This stark increase in diabetes prevalence among minorities with a normal BMI stresses each distinct level of risk for certain races/ethnicities. The data found in these groups, especially for Hawaiians/Pacific Islanders, suggest that tailored screening and prevention strategies of factors other than obesity is warranted when determining diabetes risk, the authors noted.

Based off suboptimal sleep levels shown in participants of the Jackson Heart Study, and a heightened prevalence of diabetes found in minority groups even with normal BMI, a study published this week in the Journal of the American Heart Association reveals a potentially fatal risk among these groups.³

In the study, middle-aged adults with high blood pressure or diabetes were at a doubled risk for heart disease or stroke when sleeping less than 6 hours per day (hazard ratio = 2.14; 95% CI, 1.52-3.02). As minorities are at a higher predisposed risk for diabetes, sleeping at suboptimal levels can cause detrimental health effects. Researchers, however, noted that this increased risk of early death for people with high blood pressure or diabetes was negligible if they slept for more than 6 hours.

The ability to diminish risk of sleep-related conditions was highlighted by lead study author Trimella Jefferson, MPH, an epidemiologist at the Mississippi State Department of Health, who examined the correlation of sleep duration and obesity in African Americans.¹ “The good news is sleep is something most people can control, regardless of other factors, like income and education levels…Spreading information can be very empowering, especially to communities that struggle with obesity,” said Jefferson.

Controlling for personalized factors like sleep would prove invaluable for minority groups who are at a higher risk for metabolic disorders such as diabetes. Increased research on these populations would additionally benefit awareness of attributable risks and whether certain medications are effective on all races/ethnicities. As African American children were shown to respond differently to asthma medications, the significance of minority representation in clinical studies proves vital for treatment efficacy.

Reference

1. Jefferson T, Addison C, Sharma M, et al. Association between sleep and obesity in African Americans in the Jackson Heart Study. [published September 30, 2019]. J Am Osteopath Assoc. doi: 10.7556/jaoa.2019.113.
2. Zhu Y, Sidell MA, Arterburn D, et al. Racial/ethnic disparities in the prevalence of diabetes and prediabetes by BMI. Diabetes Care. 2019 Sep; dc190532.
3. Fernandez-Mendoza J, He F, Vgontzas AN, et al. Interplay of objective sleep duration and cardiovascular and cerebrovascular diseases on cause-specific mortality. J Am Heart Assoc. 2019;8:e013043.