Sleep in older African Americans and Caucasians at risk for sleep-disordered breathing

This study explored differences in sleep between older African Americans (AA) and Caucasians (CA) at risk for sleep-disordered breathing. Seventy AA and 70 CA were compared on ambulatory monitoring sleep variables and on self-reports on health and socioeconomic status (SES). After controlling for SES and health covariates, CA woke up significantly more often than AA (p = .018), but there were no other differences in sleep variables between the two groups. Time awake at night was related to being male, more depression, less walking, and lower income, whereas having more awakenings during the night was related to being CA, higher apnea-hypopnea index, and higher periodic leg movement index. Importance of inclusion of SES, health, and other covariates in studies exploring racial differences in sleep are discussed.     

Behavioral Correlates of Sleep-Disordered Breathing in Older Men

Study Objectives:

To examine the association between sleep-disordered breathing (SDB) and subjective measures of daytime sleepiness, sleep quality, and sleep-related quality of life in a large cohort of community-dwelling older men and to determine whether any association remained after adjustment for sleep duration.

Design:

Cross-sectional. The functional outcome measures of interest were daytime sleepiness (Epworth Sleepiness Scale, ESS), sleep-related symptoms (Pittsburgh Sleep Quality Index, PSQI), and sleep-related quality of life (Functional Outcomes of Sleep Questionnaire, FOSQ). Analysis of variance and adjusted regression analyses examined the association between these outcome measures and SDB severity and actigraphy-determined total sleep time (TST). We then explored whether associations with SDB were confounded by sleep duration by adjusting models for TST.

Setting:

Community-based sample in home and research clinic settings.

Participants:

Two-thousand eight-hundred forty-nine older men from the multicenter Osteoporotic Fractures in Men Study that began in 2000. All participants underwent in-home polysomnography for 1 night and wrist actigraphy for a minimum of 5 consecutive nights.

Interventions:

N/A.

Measurements and Results:

Participants were aged 76.4 ± 5.5 years and had an apnea-hypopnea index (AHI) of 17.0 ± 15.0. AHI and TST were weakly correlated. ESS scores individually were modestly associated with AHI and TST, but the association with AHI was attenuated by adjustment for TST. PSQI and FOSQ scores were largely not associated with measures of SDB severity but were modestly associated with TST.

Conclusions:

Daytime sleepiness, nighttime sleep disturbances, and sleep-related quality of life were modestly associated with TST. After adjustment for TST, there was no independent association with SDB severity. These results underscore the potential differences in SDB functional outcomes in older versus young and middle-aged adults.

Citation:

Kezirian EJ; Harrison SL; Ancoli-Israel S; Redline S; Ensrud K; Goldberg AN; Claman DM; Spira AP; Stone KL. Behavioral correlates of sleep-disordered breathing in older men. SLEEP 2009;32(2):253–261.     

Sleep disorders in African Americans and Caucasian Americans: a meta-analysis

Previous research suggests that ethnic groups differ in the prevalence and severity of disordered sleep symptoms. This study used meta-analysis to determine the magnitude of ethnic differences between African Americans (AAs) and Caucasian Americans (CAs) in insomnia symptoms and sleep-disordered breathing (SDB). It also used moderator analyses to explore the variability in these effect sizes. Thirteen studies measuring insomnia symptoms and 10 studies measuring SDB met inclusion criteria and represented thousands of adult AAs and CAs. Results indicate AAs have a higher prevalence and greater severity of SDB, but CAs report more insomnia symptoms. These results indicate a need for a multi-ethnic approach to the assessment and treatment of sleep disorders.     

The Effect of Sleep-Disordered Breathing on Stages of Sleep in Patients With Alzheimer's Disease

Patients with Alzheimer's disease (AD) commonly have poor sleep and a high reported incidence of sleep-disordered breathing (SDB). This study examined how the presence of SDB affected sleep stages in AD patients. Sixty-six volunteers with mild–moderate AD underwent home polysomnography. Results showed that patients with SDB spent less of the night in REM sleep than those with no SDB, but there were no differences in other sleep stages. The findings suggest that the decreased amount of REM sleep may be due to the presence of AD and SDB. Treating these patients' SDB may increase their amount of REM sleep, which may result in improved daytime functioning. Controlled trials of SDB treatment in AD are needed to answer this question.     

Differential aerobic exercise-induced changes in plasma aldosterone between African Americans and Caucasians

Aldosterone influences the kidney's regulation of blood pressure (BP), but aldosterone can contribute to the pathogenesis of hypertension. Blood pressure is reduced with aerobic exercise training (AEX), but the extent to which plasma aldosterone (PA) levels change is unclear. The purpose of this study was to determine whether 6 months of AEX changed PA levels, 24 h sodium (Na(+)) excretion and BP in prehypertensive and hypertensive subjects and whether these changes differed according to ethnicity. The study was performed in the Kinesiology Department at the University of Maryland, College Park, and 35 (22 Caucasian; 13 African American) sedentary prehypertensive and hypertensive subjects completed 6 months of AEX. Blood samples were collected under fasting and supine conditions, and PA was measured by radioimmunoassay. In total population aerobic exercise training increased maximal oxygen consumption (24 +/- 0.8 versus 28 +/- 1 ml kg(-1) min(-1), P < 0.001) and decreased PA levels (97 +/- 11 versus 72 +/- 6 pg ml(-1), P = 0.01), body mass index (28 +/- 0.5 versus 28 +/- 0.5 kg m(-2), P = 0.004) and weight (85 +/- 2 versus 83 +/- 2 kg, P = 0.003). Aerobic exercise training decreased PA levels (from 119 +/- 16 to 81 +/- 7 pg ml(-1), P = 0.02) in the Caucasians but there was no change in BP or Na(+) excretion. African American participants had no significant changes in PA levels, BP and Na(+) excretion. Plasma aldosterone levels were 47% lower at baseline (P = 0.01) and 30% lower after AEX (P = 0.04) in African American participants compared with Caucasians. Baseline (P = 0.08) and final PA levels (P = 0.17) did not differ between the two groups after accounting for baseline and final intra-abdominal fat, respectively. The reduction in PA levels with AEX appeared to be driven by the change in PA levels in Caucasian participants. Fat distribution contributed to the ethnic differences in PA levels.     

Sleep-Disordered Breathing in the National Football League

Study Objectives:

Prior studies have suggested that the prevalence of sleep disordered breathing (SDB) among players in the National Football League (NFL) is disproportionately high. SDB can increase cardiovascular disease risk and is correlated with hypertension. NFL players have a higher prevalence of hypertension, and we sought to determine the prevalence of SDB among players the NFL and the associations of SDB with anthropometric measures and cardiovascular risk factors.

Design:

Cross-sectional cohort study.

Setting:

NFL athletic training facilities from April to July 2007.

Participants:

A total of 137 active veteran players from 6 NFL teams.

Measurements:

This evaluation of SDB among players in the NFL used a single-channel, home-based, unattended, portable, sleep apnea monitor. Multiple domains of self-reported sleep were assessed. Weight, body mass index, body fat percentage, neck circumference, waist circumference, and waist-to-hip ratio, as well as blood pressure, cholesterol, and fasting glucose concentrations were measured.

Results:

The mean respiratory disturbance index was 4.7 (± 12), with a median (interquartile range) of 2 (1,4). The prevalence of at least mild SDB (RDI ≥ 5) was 19% (95% confidence interval, 12.8%-26.6%). Only 4.4% (95% confidence interval, 1.6%-9.2%) of participants had respiratory disturbance index of 15 or greater. Linemen and non-linemen were not different in their prevalence or severity of SDB. No single anthropometric measure was highly associated with SDB, and SDB was not well correlated with cardiovascular risk factors.

Conclusions:

The prevalence of SDB in active NFL players was modest, predominately mild, and positively associated with several measures of adiposity. SDB did not account for excess cardiovascular risk factors.

Citation:

Rice TB; Dunn RE; Lincoln AE; Tucker AM; Vogel RA; Heyer RA; Yates AP; Wilson PWF; Pellmen EJ; Allen TW; Newman AB; Strollo PJ. Sleep-disordered breathing in the National Football League.     

HLA disease association and protection in HIV infection among African Americans and Caucasians

In a previous investigation, we demonstrated an increased progression of overt AIDS in the African American population compared to the Caucasian population as reflected by the significantly lower absolute number of CD4+ lymphocytes detected in the African American population in an earlier study. The present study elucidates some of the possible genetic factors which may contribute to disease association or protection against HIV infection. The HLA phenotypes expressed as A, B, C, DR and DQw antigens were revealed by the Amos-modified typing procedure. NIH scoring was utilized to designate positive cells taking up trypan blue. A test of proportion equivalent to the chi 2 approximation was used to compare the disease population (n = 62; 38 African Americans, 24 Caucasians) to race-matched normal heterosexual local controls (323 African Americans, 412 Caucasians). Significant p values were corrected for the number of HLA antigens tested. HLA markers associated with possible protection from infection for African Americans were Cw4 and DRw6, whereas Caucasians expressed none. Disease association markers present in the African American population were A31, B35, Cw6, Cw7, DR5, DR6, DRw11, DRw12, DQw6 and DQw7, whereas in the Caucasian population A28, Aw66, Aw48, Bw65, Bw70, Cw7, DRw10, DRw12, DQw6 and DQw7 were demonstrated. The highest phenotypic frequency for a disease association marker in the study was for HLA-DR5 (62.9%) in the HIV-infected African American population without Kaposi's sarcoma compared to a frequency of 28.9% for the regional control group (p = 0.0012). We conclude that genetic factors do have a role in HIV infection since only 50-60% of those exposed to the AIDS virus will become infected.     

Longitudinal Evaluation of Sleep-Disordered Breathing and Sleep Symptoms with Change in Quality of Life: The Sleep Heart Health Study (SHHS)

Study Objectives:

Findings from population studies evaluating the progression and incidence of sleep disordered breathing have shown evidence of a longitudinal increase in the severity of sleep disordered breathing. The present study evaluates the association among changes in sleep disordered breathing, sleep symptoms, and quality of life over time.

Design:

Prospective cohort study. Data were from the Sleep Heart Health Study.

Setting:

Multicenter study.

Participants:

Three thousand seventy-eight subjects aged 40 years and older from the baseline and follow-up examination cycles were included.

Measurements:

The primary outcomes were changes in the Physical Component Summary and Mental Component Summary scales obtained from the Medical Outcomes Study Short-Form Health Survey. The primary exposure was change in the respiratory disturbance index obtained from unattended overnight polysomnograms performed approximately 5 years apart. Other covariates included measures of excessive daytime sleepiness and difficulty initiating and maintaining sleep.

Results:

Mean respiratory disturbance index increased from 8.1 ± 11 SD at baseline to 10.9 ± 14 (P < 0.0001) at follow-up. The mean Physical Component Summary and Mental Component Summary scores were 48.5 and 54.1 at baseline and 46.3 and 54.8 at follow-up. No associations between change in respiratory disturbance index and changes in Physical Component Summary or Mental Component Summary scores were seen. However, worsening of difficulty initiating and maintaining sleep and excessive daytime sleepiness were significantly associated with lower quality of life.

Conclusions:

A slight increase in severity of sleep disordered breathing was seen over 5 years; this was not associated with worsening of quality of life. However, subjective symptoms of quality of sleep and daytime sleepiness were associated with declining quality of life.

Citation:

Silva GE; An MW; Goodwin JL; Shahar E; Redline S; Resnick H; Baldwin CM; Quan SF. Longitudinal evaluation of sleep-disordered breathing and sleep symptoms with change in quality of life: the Sleep Heart Health Study (SHHS). SLEEP 2009;32(8):1049-1057.     

Haplotype structure of the beta adrenergic receptor genes in US Caucasians and African Americans

The beta-adrenergic receptors (beta-AR) are G protein-coupled receptors activated by epinephrine and norepinephrine and are involved in a variety of their physiological functions. Previously, three beta-AR genes (ADRB1, ADRB2 and ADRB3) were resequenced, identifying polymorphisms that were used in genetic association studies of cardiovascular and metabolic disorders. These studies have produced intriguing but inconsistent results, potentially because the known functional variants: ADRB1 Arg389Gly and Gly49Ser, ADRB2 Arg16Gly and Gln27Glu, and ADRB3 Arg64Trp provided an incomplete picture of the total functional diversity at these genes. Therefore, we created marker panels for each beta-AR gene that included the known functional markers and also other markers evenly spaced and with sufficient density to identify haplotype block structure and to maximize haplotype diversity. A total of 27 markers were genotyped in 96 US Caucasians and 96 African Americans. In both populations and for each gene, a single block with little evidence of historical recombination was observed. For each gene, haplotype captured most of the information content of each functional locus, even if that locus was not genotyped, and presumably haplotype would capture the signal from unknown functional loci whose alleles are of moderate abundance. This study demonstrates the utility of using beta-AR gene haplotype maps and marker panels as tools for linkage studies on beta-AR function.     

The Sleep of African Americans: A Comparative Review

Researchers have not thoroughly assessed the sleep of African Americans (AAs) despite the recent increased attention to ethnic research. This article reviews the sleep and epidemiological literatures to assess AA sleep. Although the limited data were sometimes inconsistent, they suggest that AAs sleep worse than Caucasian Americans. AAs take longer to fall asleep, report poorer sleep quality, have more light and less deep sleep, and nap more often and longer. AAs have a higher prevalence of sleep-disordered breathing and exhibit more risk factors for poor sleep. These differences are concentrated in young- and middle-age adults. There are no sleep disorders treatment data for AAs. These data support further research into ethnic differences in both normal and disturbed sleep.     

Multiple sclerosis in Caucasians and Latino Americans

Epidemiological and genetic studies suggest that the prevalence, median age of onset, and specific phenotypes of multiple sclerosis (MS) are different in Caucasians and Latino Americans. Recent epidemiological studies indicate an increase in MS prevalence in Latin America (LA), where the south-north gradient of latitude described for Nordic countries does not exist. Analysis of MS epidemiological and specific aspects in LA suggests that susceptibility and clinical behavior of the disease are related to mixtures and admixtures of genes in the population. MS is not present in Amerindians with Mongoloid genes, such as occurs in other pure ethnic groups. Surely, future studies will be carried out to obtain more reliable information. In this review, we contrast and analyze the available data of MS in LA and endemic countries.     

Multiple sclerosis in Caucasians and Latino Americans

Epidemiological and genetic studies suggest that the prevalence, median age of onset, and specific phenotypes of multiple sclerosis (MS) are different in Caucasians and Latino Americans. Recent epidemiological studies indicate an increase in MS prevalence in Latin America (LA), where the south–north gradient of latitude described for Nordic countries does not exist. Analysis of MS epidemiological and specific aspects in LA suggests that susceptibility and clinical behavior of the disease are related to mixtures and admixtures of genes in the population. MS is not present in Amerindians with Mongoloid genes, such as occurs in other pure ethnic groups. Surely, future studies will be carried out to obtain more reliable information. In this review, we contrast and analyze the available data of MS in LA and endemic countries.     

Comparing Night-to-Night Variability of Sleep Measures in Elderly African Americans and Whites

There has been great interest in the night-to-night variability of sleep-disordered breathing because of the implications for the accuracy and costs associated with diagnostic testing. Night-to-night variability of sleep and respiratory parameters were examined in 66 older Whites and 56 older African Americans. Each participant had his or her sleep recorded for 2 nights with portable recording equipment. The correlations between the 2 nights were all large. Analyses of variance showed that men had a greater change in apnea index and in number of apneas than women. There were no differences in the parameters for African Americans versus Whites. One night of sleep recording may be sufficient for studying sleep disorders in elderly persons.     

Simple Four-Variable Screening Tool for Identification of Patients with Sleep-Disordered Breathing

Objective:

To aid in the identification of patients with moderate-to-severe sleep-disordered breathing (SDB), we developed and validated a simple screening tool applicable to both clinical and community settings.

Methods:

Logistic regression analysis was used to develop an integer-based risk scoring system. The participants in this derivation study included 132 patients visiting one of 2 hospitals in Japan, and 175 residents of a rural town. The participants in the present validation study included 308 employees of a company in Japan who were undergoing a health check.

Results:

The screening tool consisted of only 4 variables: sex, blood pressure level, body mass index, and self-reported snoring. This tool (screening score) gave an area under the receiver operating characteristic curve (ROC) of 0.90, sensitivity of 0.93, and specificity of 0.66, using a cutoff point of 11. Predicted and observed prevalence proportions in the validation dataset were in close agreement across the entire spectrum of risk scores. In the validation dataset, the area under the ROC for moderate-to-severe SDB and severe SDB were 0.78 and 0.85, respectively. The diagnostic performance of this tool did not significantly differ from that of previous, more complex tools.

Conclusion:

These findings suggest that our screening scoring system is a valid tool for the identification and assessment of moderate-to-severe SDB. With knowledge of only 4 easily ascertainable variables, which are routinely checked during daily clinical practice or mass health screening, moderate-to-severe SDB can be easily detected in clinical and public health settings.

Citation:

Takegami M; Hayashino Y; Chin K; Sokejima S; Kadotani H; Akashiba T; Kimura H; Ohi M; Fukuhara S. Simple four-variable screening tool for identification of patients with sleep-disordered breathing. SLEEP 2009;32(7):939-948.     

Clinical Presentation of Hepatocellular Carcinoma in African Americans vs. Caucasians: A Retrospective Analysis

Hepatocellular carcinoma (HCC) remains an important form of cancer-related morbidity and mortality in the U.S. and worldwide. Previous U.S.-based studies on survival suggest ethnic disparities in HCC patients, but the complex interplay of multiple factors that contribute are still incompletely understood. Here we considered the influences of risk factors contributing towards HCC survival, including ethnic background, over ten years at a premier academic medical center with a majority (57.20%) African American (AA) population. Retrospective HCC data were collected from 2008–2018 at LSUHSC-Shreveport, an urban tertiary medical center. Data included demographics, comorbidities, liver disease characteristics, and tumor parameters. Statistical analysis was performed using Chi Square and one-way ANOVA. Results: 229 HCC patients were identified (male 78.6%). The mean HCC age at diagnosis was 61 years (SD = 7.3). Compared to non-Hispanic Caucasians (42.7%), AA patients (57.2% of total) were older at presentation, had more frequent diabetes/dyslipidemia/NAFLD (45 (34.3%) compared with 19 (19.3%) in non-Hispanic Caucasians, p = 0.02), and had a larger HCC burden at diagnosis. We conclude that compared to white patients, despite having similar BMI and MELD scores and rates of portal vein thrombosis, AA patients with HCC in our cohort were older at presentation, had a significantly increased incidence of modifiable metabolic risk factors including diabetes, higher AFP values, increased incidence of gallstones, and larger sized HCCs, and were more likely to be outside Milan criteria. These findings have important prognostic and diagnostic implications for developing a more targeted HCC surveillance program.