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Biomedical subjects

Stuart F Quan

Publications and source records attributed to Stuart F Quan.

At least 19 recordsLinked to original sources
PubMed2007

Comparison between reported and recorded total sleep time and sleep latency in 6- to 11-year-old children: the Tucson Children's Assessment of Sleep Apnea Study (TuCASA).

Research comparing parental report of sleep times to objectively obtained polysomnographic evidence of sleep times in schoolchildren is lacking. This report compares habitual sleep time and objectively recorded sleep time and sleep latency with parental reports of sleep time immediately after a night of polysomnography in elementary schoolchildren. Unattended home polysomnograms (PSG) were obtained from 480 children. On the night of the PSG, a parent was asked to complete a Sleep Habits Questionnaire, which inquired about the habitual total sleep time (HABTST) and habitual sleep onset latency (HABSOL) of his/her child on both school days and nonschool days. On the morning after the PSG, the parent was asked to estimate the total sleep time (ESTTST) and sleep onset latency (ESTSOL) of his/her child on the night of the recording. Comparisons were made to actual total sleep time (PSGTST) and sleep latency (PSGSOL) on the PSG. The sample was comprised of 50% girls, 42.3% Hispanic, and 53% aged 6-8 years. The mean HABTST, ESTTST, and PSGTST were 578, 547, and 480 min, respectively. HABTST was greater than both ESTST and PSGTST (p < 0.001). Moreover, ESTTST was greater than PSGTST (p < 0.001). The mean HABSOL, ESTSOL, and PSGSOL were 15, 17, and 11 min. ESTSOL was longer than PSGSOL (p < 0.001). There were no gender differences. However, Hispanic parents reported significantly less HABTST in their children than Caucasian parents (566 vs 587 min, p < 0.001). Parents of schoolchildren in this population-based sample substantially overestimated their children's actual total sleep time and sleep onset latency.

Adult↗
PubMed2007

Association of physical activity with sleep-disordered breathing.

This study was performed to determine whether there is a protective association between participation in vigorous or vigorous/moderately vigorous physical activity and the prevalence of sleep-disordered breathing (SDB). Polysomnographic and questionnaire data from the baseline examination of 4,275 participants in the Sleep Heart Health Study (SHHS) were analyzed in relation to information on amount of physical activity and other potentially relevant factors collected from five SHHS parent cohorts (Atherosclerosis Risk in Communities Study, Cardiovascular Health Study, Framingham Heart Study, Strong Heart Study, and Tucson Epidemiologic Study of Airways Obstructive Diseases). Logistic regression models were fitted to determine if amount and strenuousness of physical activity was associated with the presence of SDB. At least 3 h per week of vigorous physical activity reduced the odds of SDB, defined as a respiratory disturbance index (RDI) of at least 15 apneas/hypopneas per hour (Adjusted OR, 0.68; 95%CI, 0.51-0.91). A qualitatively similar but slightly weaker association was observed when SDB was defined as a RDI > or = 10 per hour (Adjusted OR, 0.81; 95%CI, 0.64-1.02). These findings remained after adjustment for sleepiness and restricting analyses to participants with good health. Three or more hours of moderately vigorous or vigorous physical activity also appeared to confer some protection against SDB, but these associations were weaker. Gender- and obesity-stratified analyses suggested that the protective association between physical activity and SDB occurred primarily in men and those who were obese. A program of regular vigorous physical activity of at least 3 h per week may be a useful adjunctive treatment modality for SDB, but this association needs confirmation with a prospective clinical trial.

Adult↗
PubMed2006

Parent-rated behavior problems associated with overweight before and after controlling for sleep disordered breathing.

BACKGROUND: Researchers and clinicians are seeking to develop efficacious behavioral interventions to treat overweight children; however, few studies have documented the behavioral correlates of overweight children in community samples. The goal of this study was to determine the nature and prevalence of behavior problems for overweight school-aged children versus normal weight peers before and after controlling for the effect of sleep disordered breathing. METHODS: Hispanic and Caucasian children were invited to participate in a study of sleep through public elementary school classrooms. Anthropometric evaluation and behavioral ratings were collected for 402 children aged 6-11 years. Overweight was calculated using the Centers for Disease Control age- and gender-specific guidelines. Children were classified as overweight if they were at or above the 95th percentile for their age and gender group. Behavior problems were measured using the Conners' Parent Rating Scales-Revised and the Child Behavior Checklist. Sleep disordered breathing was assessed using in-home overnight polysomnography. RESULTS: Approximately 15% (59/402) of the sample was classified as overweight. Simple odds ratios indicated that overweight children were more likely to have clinically relevant levels of internalizing symptoms (OR 2.23, CI 1.05-4.72), psychosomatic complaints (OR 2.15, CI 1.02-4.54), withdrawal (OR 4.69, CI 2.05-10.73), and social problems (3.18, 1.53-6.60). When odds ratios were adjusted for level of sleep disordered breathing, withdrawal (OR 3.83 CI 1.59-9.22) and social problems (OR 2.49 CI 1.14-5.44) remained significantly higher for overweight subjects. CONCLUSION: After controlling for the effect of sleep disordered breathing, behaviors such as withdrawal and social problems, are common in overweight children and need to be taken into account in the design of interventions and services as they may act to moderate the efficacy of behavioral treatments.

Body Weight↗
PubMed2006

Obstructive sleep apnea-hypopnea and neurocognitive functioning in the Sleep Heart Health Study.

BACKGROUND AND PURPOSE: Obstructive sleep apnea-hypopnea (OSAH) is associated with sleep fragmentation and nocturnal hypoxemia. In clinical samples, patients with OSAH frequently are found to have deficits in neuropsychological function. However, the nature and severity of these abnormalities in non-clinical populations is less well defined. PATIENTS AND METHODS: One hundred and forty-one participants from the Tucson, AZ and New York, NY field centers of the Sleep Heart Health Study completed a battery of neuropsychological tests for 9-40 months (mean=24 months, SD=7 months) after an unattended home polysomnogram. Sixty-seven participants had OSAH (AHI>10) and 74 did not have OSAH (control (CTL), apnea-hypopnea index (AHI)<5). In addition to the individual tests, composite variables representing attention, executive function, MotorSpeed and processing speed were constructed from the neuropsychological test battery. RESULTS: There were no significant differences in any individual neuropsychological test or composite variable between the OSAH and CTL groups. However, when time spent with O(2) saturations less than 85% was dichotomized into those participants in the top quartile of the distribution and those in the lower three quartiles, motor speed was significantly impaired in those who were more hypoxemic. In addition, poorer motor speed (model adjusted R(2)=0.242, P<0.001) and processing speed performance (model adjusted R(2)=0.122, P<0.001) were associated with more severe oxygen desaturation even after controlling for degree of daytime sleepiness, age, gender and educational level. CONCLUSIONS: Mild to moderate OSAH has little impact on the selected measures of attention, executive function, motor speed and processing speed. However, hypoxemia adversely affects both motor and processing speed. These results suggest that in middle-aged to elderly adults the neuropsychological effects of clinically unrecognized mild to moderate OSAH are neither global nor large.

Brain↗
PubMed2005

Antioxidant nutrient intake and supplements as potential moderators of cognitive decline and cardiovascular disease in obstructive sleep apnea.

Cognitive deficits and cardiovascular disease (CVD) are comorbid conditions frequently associated with obstructive sleep apnea (OSA). Oxygen free radical release and its differential regulation of cytokine synthesis and immune modulation resulting from OSA-related hypoxic events have been hypothesized as the underlying mechanism(s) for the cognitive deficits and CVD in OSA. A number of studies have suggested that increased levels of oxidative stress and/or antioxidant deficiencies may also be risk factors in cognitive decline and CVD. The influence of antioxidant nutrients and supplements, such as Vitamins B6, B12, C, E, folic acid, alpha-lipoic acid and Coenzyme Q(10) on cognitive decline and CVD have been investigated. The influence of antioxidant nutrients or supplements on OSA remains to be investigated. Even if dietary or supplemental antioxidants do not prove to be effective therapies for OSA, dietary assessment and prescription to increase dietary intake of neuro- and cardio-protective nutrients may make it possible to reduce some of the cognitive and cardiovascular sequelae associated with OSA.

Antioxidants↗
PubMed2005

Clinical screening of school children for polysomnography to detect sleep-disordered breathing--the Tucson Children's Assessment of Sleep Apnea study (TuCASA).

STUDY OBJECTIVES: This report describes the associations, specificities, sensitivities, and positive likelihood ratios of clinical symptoms to a finding of sleep-disordered breathing (SDB) on polysomnography in children. METHODS: Four hundred eighty unattended home polysomnograms were completed in a community-based cohort of children 6 to 11 years of age (50% boys, 42.3% Hispanic, and 52.9% between the ages of 6 and 8 years). SDB was present if the child had a respiratory disturbance index of > or = 1 event per hour. MEASUREMENTS AND RESULTS: Boys were twice as likely as girls to have SDB (p < .01); however, witnessed apnea, ethnicity, age, obesity, and airway size (based on clinical evaluation) were not significantly different between those with SDB and without SDB. The sensitivity of any individual or combined clinical symptoms was poor, with male sex (60%) and snoring (29.5%) having the greatest proportion of SDB children. However, high specificities for snoring (89.5%), excessive daytime sleepiness (86.3%), and learning problems (95.9%) were noted. Combinations of symptoms such as snoring+male sex (95.1%), snoring+excessive daytime sleepiness (97.0%), and snoring+learning problems (98.9%) had specificities approaching 1. Positive likelihood ratios for snoring (2.8), learning (2.8), and symptoms combined with snoring such as snoring+male sex (3.9), snoring+learning problems (4.0), and snoring+excessive daytime sleepiness (2.9) were observed. CONCLUSIONS: Snoring, excessive daytime sleepiness, and learning problems are each highly specific, but not sensitive, for SDB in 6- to 11-year old children. However, specificities and positive likelihood ratios for the combination of some of these symptoms is sufficiently high to suggest that some children may not require a polysomnogram for the diagnosis of SDB.

Child↗
PubMed2005

Behavior problems associated with sleep disordered breathing in school-aged children--the Tucson children's assessment of sleep apnea study.

OBJECTIVE: The purpose of the current study was to examine prevalence of and relations between a commonly used measure of nighttime breathing problems, the Respiratory Disturbance Index (RDI), and a range of problem behaviors in community children. METHODS: Participants were 403 unreferred children aged 6-12 years. Recruitment was completed through public elementary schools. Overnight unattended in-home polysomnography was used to assess sleep and breathing. The RDI was used as the indicator of respiratory events during sleep. The Child Behavior Checklist and the Conners' Parent Rating Scales-Revised were used to assess behavior. RESULTS: Prevalence rates for Attention, Cognitive Problems, Aggression, Oppositional behavior, and Social Problems were greatest for subjects with high RDIs. Prevalence for Internalizing behaviors was not greater for those subjects with high RDIs. Hyperactivity was not strongly related to higher RDIs. CONCLUSIONS: Behavioral problems may exist in the presence of nocturnal breathing events in unreferred children. Specific patterns of behavioral morbidity have still not been established. Some behaviors, such as hyperactivity, may show differing sensitivity and specificity in relation to the RDI.

Adolescent↗
PubMed2005

Obstructive sleep apnea and ischemic heart disease in southwestern US veterans: implications for clinical practice.

This study describes associations between obstructive sleep apnea (OSA), intake of food rich in antioxidant nutrients, and ischemic heart disease (IHD) in military veterans. Subjects were male veterans (n=211), 54 to 85 years of age, and enrolled in primary care clinics at the Southern Arizona Veterans Affairs Health Care System (SAVAHCS), Tucson, AZ. Measures included the SAVAHCS Minority Vascular Center Questionnaire, the Sleep Heart Health Study Sleep Habits Questionnaire, the Arizona Food Frequency Questionnaire, height, weight, and blood pressure. Veterans with OSA were significantly more likely to be obese, to have elevated systolic blood pressure and physician-diagnosed IHD, more likely to undergo coronary angiography, and less likely to consume foods rich in cardioprotective antioxidants compared to veterans without OSA. After adjusting for confounding variables, the association between OSA and IHD remains significant [adjusted OR=2.99, confidence interval (CI)=1.07-8.42]. These data reinforce the importance of recognizing OSA within the veterans affairs health care system and suggest that early detection of OSA may improve veterans' health and well-being and reduce associated medical costs.

Aged↗
PubMed2005

Haptoglobin phenotype, sleep-disordered breathing, and the prevalence of cardiovascular disease: the Sleep Heart Health Study.

BACKGROUND: Diabetes is an independent risk factor for cardiovascular disease, and there is growing evidence that sleep-disordered breathing also may increase the risk of cardiovascular disease. The mechanism responsible for increased susceptibility of people with diabetes to cardiovascular disease is thought to share several features with sleep-disordered breathing, notably increased oxidative stress. We recently demonstrated that a particular haptoglobin phenotype that is associated with differential antioxidant activity is an independent risk factor for cardiovascular disease in individuals with diabetes. We therefore sought to determine whether sleep-disordered breathing and cardiovascular disease are more strongly associated among people with the unfavorable haptoglobin phenotype. METHODS: We tested this hypothesis in 2612 middle-aged and older participants from the Sleep Heart Health Study. Haptoglobin phenotyping was performed by gel electrophoresis. Respiratory disturbance index was assessed by standard methods. Logistic regression analysis was performed to estimate the association between haptoglobin phenotype and cardiovascular disease, adjusting for known cardiovascular risk factors (age, sex, diabetes, smoking, lipid levels, and hypertension). Possible modification by haptoglobin phenotype of the association of sleep-disordered breathing with cardiovascular disease prevalence was explored by examining interaction terms. RESULTS: We found no significant association between haptoglobin phenotype and prevalent cardiovascular disease in this cohort, nor were significant interactions found between haptoglobin phenotype and sleep-disordered breathing on the prevalence of cardiovascular disease. CONCLUSIONS: Sleep-disordered breathing did not appear to interact with haptoglobin phenotype in modifying the association with prevalent cardiovascular disease in the Sleep Heart Health Study. These findings could be due to the absence of association or to survivor bias in these cross-sectional analyses.

Aged↗
PubMed2005

Comparison of nasal pressure transducer and thermistor for detection of respiratory events during polysomnography in children.

STUDY OBJECTIVES: The results of small studies have suggested that a nasal-cannula pressure transducer has a higher sensitivity than a thermistor in detecting hypopneas and diagnosing sleep-disordered breathing in both adults and children. We compared a thermistor alone, and in conjunction with a pressure transducer, for detection of sleep-disordered breathing in children during in-home polysomnography. DESIGN: Retrospective analysis of a subsample of a prospective cohort study. SETTING: Students attending elementary school in the Tucson Unified School District. PARTICIPANTS: A subsample of the Tucson Children's Assessment of Sleep Apnea study population. MEASUREMENTS AND RESULTS: Polysomnographic recordings of 40 children (24 girls and 16 boys, mean age 9.2 +/- 1.7 years; range 6-11 years) were analyzed to compare the detection of sleep-disordered breathing events by 2 different methods of measuring airflow: thermistor alone and thermistor with nasal-cannula pressure transducer (transducer) used simultaneously. The transducer detected all the respiratory events detected by the thermistor, but the thermistor detected only 84% of the transducer-defined events. Consequently, the transducer-derived mean respiratory disturbance index was higher than that detected by the thermistor (7.0 +/- 3.8 vs 5.9 +/- 3.4, P < .001). The bias error between transducer respiratory disturbance index and thermistor respiratory disturbance index on a Bland-Altman plot was 1.08 (95% confidence interval, 0.8 - 1.4). There was good agreement between the thermistor and the transducer for making the diagnosis of sleep apnea using a cutoff of a respiratory disturbance index greater than 5 (kappa = 0.69). The quality of the tracings with the transducer was comparable to that of the thermistor, but the transducer dislodged more frequently. CONCLUSION: The use of a nasal transducer in conjunction with a thermistor was more sensitive than the thermistor alone in detecting sleep-disordered breathing in children during unattended polysomnography.

Catheterization↗
PubMed2005

Factors associated with incidence and persistence of symptoms of disturbed sleep in an elderly cohort: the Cardiovascular Health Study.

BACKGROUND: There are limited data pertaining to the factors influencing the incidence and persistence of sleep symptoms in the elderly. The purpose of this study was to determine the incidence and nonremission rates of the following sleep symptoms: trouble falling asleep (TFA), frequent awakenings (FA), and excessive daytime sleepiness (EDS) in the Cardiovascular Health Study (CHS), a prospective multicenter study of cardiovascular disease in a large cohort of elderly adults. Factors influencing these rates were assessed as well. METHODS: 4467 participants in CHS were surveyed for the presence of TFA, FA, and EDS as well as other health problems at their baseline examination and at a follow-up examination 1 to 4 years later. RESULTS: Annualized incidence and nonremission rates were the following: TFA (2.8% and 15.4%), FA (12.3% and 22.7%), and EDS (4.4% and 13.4%). Women were more likely to have incident and persistent TFA. Depression was the primary factor predicting the incidence of all three sleep symptoms. However, other health conditions, including respiratory symptoms and cardiovascular disease, and limitation in activities of daily living were important as well. Depression also was the most important factor associated with persistence of these sleep symptoms. The role of other health conditions in determining nonremission was much more limited. CONCLUSIONS: Incidence of sleep disturbances in the elderly is related to depression, health conditions, and physical functioning. However, persistence of sleep disturbances is best predicted by the presence of depression.

Aged↗
PubMed2005

Sleep-disordered breathing and cardiovascular health.

PURPOSE OF REVIEW: Sleep-disordered breathing is a widely prevalent condition and may have serious medical, social, and economic consequences. This review evaluates the role of sleep-disordered breathing in cardiovascular morbidity and mortality on the basis of recent literature. RECENT FINDINGS: Epidemiologic studies, retrospective reviews, and prospective clinical trials suggest a strong association between sleep-disordered breathing and adverse cardiovascular events. Individuals with sleep-disordered breathing have a higher prevalence of hypertension, which attenuates with treatment. Furthermore, the presence of sleep-disordered breathing augurs an increased risk of coronary artery disease, cardiac arrhythmias, and heart failure. SUMMARY: Recent research provides an emerging evidence of the role of sleep-disordered breathing as a risk factor for diverse cardiovascular disorders.

Cardiovascular Diseases↗
PubMed2005

Predictors of heartburn during sleep in a large prospective cohort study.

BACKGROUND AND AIMS: Nocturnal gastroesophageal reflux, which may result in nocturnal heartburn, has been demonstrated to be associated with a more severe form of gastroesophageal reflux disease (GERD). The aim of this study was to determine the clinical predictors of heartburn during sleep in a large prospective cohort study. METHODS: Study subjects were members of the parent cohorts from which the Sleep Heart Health Study (SHHS) recruited participants. SHHS is a multicenter, longitudinal, cohort study of the cardiovascular consequences of sleep-disordered breathing. As part of the recruitment process, parent cohort members completed a questionnaire that permitted an assessment of the relationships between heartburn during sleep, and patient demographics, sleep abnormalities, medical history, and social habits in nine community-based parent cohorts across the United States. All variables, significant at the p < 0.05 level, were included as independent variables in multivariate logistic regression models with heartburn during sleep status included as the dependent variable RESULTS: A total of 15,314 subjects completed the questions about heartburn during sleep, and of these, 3,806 subjects (24.9%) reported having this symptom. In four increasingly comprehensive multivariate models, increased body mass index (BMI), carbonated soft drink consumption, snoring and daytime sleepiness (Epworth sleepiness scale score), insomnia, hypertension, asthma, and usage of benzodiazepines were strong predictors of heartburn during sleep. In contrast, college education decreased the risk of reporting heartburn during sleep. CONCLUSIONS: Heartburn during sleep is very common in the general population. Reports of this type of symptom of GERD are strongly associated with increased BMI, carbonated soft drink consumption, snoring and daytime sleepiness, insomnia, hypertension, asthma, and usage of benzodiazepines. Overall, heartburn during sleep may be associated with sleep complaints and excessive daytime sleepiness.

Aged↗
PubMed2004

Polysomnography performed in the unattended home versus the attended laboratory setting--Sleep Heart Health Study methodology.

STUDY OBJECTIVE: To compare polysomnographic recordings obtained in the home and laboratory setting. DESIGN AND SETTING: Multicenter study comparing unsupervised polysomnography performed in the participant's home with polysomnography supervised at an academic sleep disorders center, using a randomized sequence of study setting. Sleep Heart Health Study (SHHS) standardized polysomnographic recording and scoring techniques were used for both settings. PARTICIPANTS: 64 of 76 non-SHHS participants recruited from 7 SHHS field sites who had both a laboratory and home polysomnogram meeting acceptable quality criteria. MEASUREMENTS AND RESULTS: Median sleep duration was greater in the home than in the laboratory (375 vs 318 minutes, respectively, P < .0001) as was sleep efficiency (86% vs 82%, respectively, P < .0024). Very small, but significant increases in percentage of rapid eye movement sleep and decreases in stage 1 sleep were noted in the laboratory. Employing multiple definitions of respiratory disturbance index (RDI), median RDI was similar in both settings (for example, RDI with 3% desaturation: home 12.4, range 0.6-67; laboratory 9.5, range 0.1-93.4, P = .41). Quartile analysis of laboratory RDI showed moderate agreement with home RDI measurements. Based on the mean of laboratory and home RDI and using a cutpoint of 20, there was a biphasic distribution, with the RDI 3% above 20 being more common in the recordings performed in the laboratory than in the home and below 20 being more common in the recordings performed in the home than in the laboratory. These differences could not be attributed to quality of recording, age, sex, or body mass index. CONCLUSIONS: Using SHHS methodology, median RDI was similar in the unattended home and attended laboratory setting with differences of small magnitude in some sleep parameters. Differences in RDI between settings resulted in a rate of disease misclassification that is similar to repeated studies in the same setting.

Adult↗