Original ArticleRacial/ethnic differences in the associations between obesity measures and severity of sleep-disordered breathing: the Multi-Ethnic Study of Atherosclerosis
Introduction
The burdens of obesity and sleep-disordered breathing (SDB) are disproportionately borne by racial/ethnic minorities in the United States [1], [2]. Both obesity and SDB are associated with hypertension, diabetes, cardiovascular disease (CVD), and mortality [3], [4], [5], [6], [7], [8]. Previous studies have shown some variations in the prevalence and severity of SDB by race/ethnicity [9], [10], [11]. For example, in a cross-sectional study of 308 obese patients with body mass index (BMI) of ≥35 kg/m2, South Asians had a significantly higher prevalence and more severe SDB than White Europeans [11]. Our recent findings in the Multi-Ethnic Study of Atherosclerosis (MESA) indicate that SDB is prevalent among middle-aged and older US adults, and that Hispanics and Chinese have higher odds of SDB than Whites after considering the influence of BMI [12]. Although SDB appears to vary by race/ethnicity, the basis for this variation is unclear.
Obesity is a strong risk factor for SDB. Although the association between obesity and SDB has been well established in theliterature, less is known regarding whether the strength of this association varies across racial/ethnic groups. Sands-Lincoln and colleagues showed that the relationship between sleep apnea and hypertension depended on race/ethnicity and obesity [8]. There may be a complex association among SDB, race/ethnicity, and obesity. Furthermore, other risk factors for SDB, such as craniofacial structure, upper airway collapsibility, and ventilatory control, may also vary across population groups [13]. As BMI and body fat distribution vary by race/ethnicity [14], it is important to understand whether group differences in SDB are related to differences in levels of BMI or to differences in central obesity (as measured by waist circumference), or to propensity for SDB with incremental increases in body weight. This information may help identify risk factors that confer increased SDB within racial/ethnic groups, and it may also help develop targeted intervention strategies.
This study aimed to better understand how variation in body weight and body fat distribution was associated with SDB severity within racial/ethnic groups after adjustment for possible confounders, including sociodemographic factors, physical activity, smoking status, and comorbidities. We also sought to explore potential variation in these associations by age and sex. We systematically evaluated the associations between general (BMI) and abdominal obesity (waist circumference) measures with polysomnography (PSG)-measured SDB severity across four racial/ethnic groups (White, Black, Hispanic, and Chinese Americans). Waist circumference has been considered a simple and valuable anthropometric measure of abdominal obesity [15]. As age and sex are related to obesity and SDB severity [1], [6], we conducted exploratory analyses to examine the potential three-way interactions of age, sex, and race/ethnicity with BMI and waist circumference pertaining to SDB severity.
Section snippets
Study design and participants
MESA is a multisite prospective study designed to investigate the prevalence and progression of subclinical CVD, and to identify risk factors for incident CVD in a racially/ethnically diverse sample. The description of the study design for MESA has been published [16]. Briefly, between 2000 and 2002, a total of 6814 men and women who identified themselves as White, Black/African-American, Hispanic, or Chinese aged 45–84 years and free of clinically apparent CVD were recruited from six US
Participant characteristics
Table 1 displays sociodemographic and clinical characteristics of study participants by race/ethnicity. Participants were on average of 68.4 [standard deviation (SD): 9.1]; range: 54–93 years old; 53.6% of participants were female. The mean BMI was lowest for Chinese (mean = 24.2; SD = 3.3), followed by Whites (mean = 28.0; SD = 5.2), Hispanics (mean = 30.0; SD = 5.5), and Blacks (mean = 30.3; SD = 5.6). The mean waist circumference was also lowest for Chinese, followed by Whites, Hispanics,
Discussion
A comparison of the prevalence and risk factors for SDB across racial/ethnic groups can be helpful for identifying social, environmental, and genetic factors that may contribute to SDB. However, to date, few studies have explored the complex associations among race/ethnicity, obesity measures, and SDB severity in direct interethnic comparisons. Given the availability of rigorously collected PSG data as well as anthropometric measures in a relatively large multiethnic cohort, we were able to
Conflict of interest
All authors have no conflict of interest in relation to the work described.
The ICMJE Uniform Disclosure Form for Potential Conflicts of Interest associated with this article can be viewed by clicking on the following link: http://dx.doi.org/10.1016/j.sleep.2015.06.003.
Acknowledgments
The Multi-Ethnic Study of Atherosclerosis (MESA) is supported by contracts N01-HC-95159 through N01-HC-95169 from the National Heart, Lung, and Blood Institute (NHLBI) at the National Institutes of Health. The work presented in this paper was supported by grants from NIH 1R01HL083075-01, R01HL098433, R01 HL098433-02S1, 1U34HL105277-01, 1R01HL110068-01A1 1R01HL113338-01, R21 HL108226, P20 NS076965, 3R01HL115941-01S1, UL1TR001102, 5T32HL007901, and R01 HL109493. This work was also supported by an
References (38)
- et al.
Waist worries
Am J Clin Nutr
(2002) - et al.
Global, regional, and national prevalence of overweight and obesity in children and adults during 1980–2013: a systematic analysis for the Global Burden of Disease Study 2013
Lancet
(2014) - et al.
Comparison of the severity of sleep-disordered breathing in Asian and Caucasian patients seen at a sleep disorders center
Respir Med
(1998) - et al.
Computed tomographic evaluation of the role of craniofacial and upper airway morphology in obstructive sleep apnea in Chinese
Respir Med
(2004) - et al.
Cephalometric assessment of craniofacial morphology in Chinese patients with obstructive sleep apnoea
Respir Med
(2003) - et al.
Neighborhood disadvantage as a risk factor for pediatric obstructive sleep apnea
J Pediatr
(2006) - et al.
Liking for high fat foods in patients with Obstructive Sleep Apnoea
Appetite
(2014) - et al.
Prevalence of childhood and adult obesity in the United States, 2011–2012
JAMA
(2014) - et al.
Racial differences in sleep-disordered breathing in African-Americans and Caucasians
Am J Respir Crit Care Med
(1997) - et al.
Prospective study of the association between sleep-disordered breathing and hypertension
N Engl J Med
(2000)