Self-reported race and genetic admixture.
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Black People↗
Biomedical subjects
Emma K Larkin
Publications and source records attributed to Emma K Larkin.
Apolipoprotein E and obstructive sleep apnea: evaluating whether a candidate gene explains a linkage peak.
Evidence from both linkage analyses and association-based analyses has implicated Apoliprotein E (ApoE) as a disease susceptibility locus for obstructive sleep apnea. To further assess the putative role of ApoE in sleep apnea, we performed genotyping, association, and linkage analyses in a cohort assembled to investigate the genetic epidemiology of sleep apnea. Among a subset of the Caucasian families, ten microsatellites, spanning 20 cM, were genotyped in a region near ApoE on chromosome 19 where previous suggestive linkage had been demonstrated using a 9.1-cM genome-wide scan. Haseman-Elston regression analysis, conducted with these fine mapping markers (n=196 sibling pairs, 56 families), showed evidence for linkage to marker AFM210yg9 (p=0.00034), which was increased over that observed with the original scan. ApoE genotyping also was performed on a larger set of data (n=1,211 from 271 families, ages 3-85 years) from the cohort with available DNA. To determine whether the ApoE genotype explains the linkage peak, we included the ApoE genotype as a covariate in regression models. Inclusion of ApoE E2 allele as a covariate reduced the regression coefficient by 18%, suggesting that ApoE does not substantively explain the linkage signal. Finally, we repeated an association-based analysis in the larger sample of 1,211 individuals, and observed a higher prevalence of sleep apnea among individuals with the ApoE E2 allele. Overall, the evidence suggests that there is a disease susceptibility locus for obstructive sleep apnea in the region of ApoE, but ApoE itself is unlikely to be the causative locus.
Adolescent↗
A regression based transmission/disequilibrium test for binary traits: the power of joint tests for linkage and association.
BACKGROUND: In this analysis we applied a regression based transmission disequilibrium test to the binary trait presence or absence of Kofendred Personality Disorder in the Genetic Analysis Workshop 14 (GAW14) simulated dataset and determined the power and type I error rate of the method at varying map densities and sample sizes. To conduct this transmission disequilibrium test, the logit transformation was applied to a binary outcome and regressed on an indicator variable for the transmitted allele from informative matings. All 100 replicates from chromosomes 1, 3, 5, and 9 for the Aipotu and the combined Aipotu, Karangar, and Danacaa populations were used at densities of 3, 1, and 0.3 cM. Power and type I error were determined by the number of replicates significant at the 0.05 level. RESULTS: The maximum power to detect linkage and association with the Aipotu population was 93% for chromosome 3 using a 0.3-cM map. For chromosomes 1, 5, and 9 the power was less than 10% at the 3-cM scan and less than 22% for the 0.3-cM map. With the larger sample size, power increased to 38% for chromosome 1, 100% for chromosome 3, 31% for chromosome 5, and 23% for chromosome 9. Type I error was approximately 7%. CONCLUSION: The power of this method is highly dependent on the amount of information in a region. This study suggests that single-point methods are not particularly effective in narrowing a fine-mapping region, particularly when using single-nucleotide polymorphism data and when linkage disequilibrium in the region is variable.
Chromosomes, Human↗
Variation of C-reactive protein levels in adolescents: association with sleep-disordered breathing and sleep duration.
BACKGROUND: There is increasing evidence that sleep-disordered breathing (SDB) is an independent risk factor for cardiovascular disease (CVD) in adults. C-reactive protein (CRP), a marker of systemic inflammation, is an important predictor of future cardiovascular events. The goal of this study was to quantify the associations of SDB, sleep duration, and CRP in adolescents to better understand the role of SDB in CVD risk. METHODS AND RESULTS: Adolescents (n=143; age, 13 to 18 years; 36% black; 50% female) with a wide range of SDB severity underwent polysomnography and measurement of high-sensitivity CRP. SDB was quantified with the apnea hypopnea index (AHI) and oxygen desaturation measures. Sleep duration was estimated from 7-day actigraphy. The independent and dose-response associations of SDB with CRP were addressed through linear mixed-effects models. Forty-eight percent were overweight or obese, and 12% had SDB (AHI > or =5). CRP levels varied with increasing body mass index and SDB. After adjustment for body mass index , age, sex, and race, mean CRP levels were 0.50, 0.43, 0.97, and 1.66 mg/L for SDB severity levels of AHI <1, 1 to 4.9, 5 to 14.9, and > or =15, respectively (P=0.0049, AHI > or =15 versus <1). Adjusted mean CRP levels demonstrated a dose response with SDB above a threshold AHI of 5. This association was partially explained by overnight hypoxemia and less so by sleep duration. CONCLUSIONS: In adolescents free of known CVD, an AHI > or =5 is associated with increasing levels of CRP, suggesting that pediatric SDB may confer additional CVD risk beyond that of obesity.
Adolescent↗
Sex influences endothelial function in sleep-disordered breathing.
BACKGROUND: The bases for the association between sleep-disordered breathing (SDB) and cardiovascular disease are poorly understood. Endothelial dysfunction, assessed with brachial artery ultrasonography, may predict cardiovascular risk and represent preclinical vascular disease. We determined whether flow-mediated dilation (FMD) and peak blood flow (PBF) increase after cuff occlusion is altered with SDB. METHODS: 193 participants (58% women) in a cohort study were studied with overnight polysomnography and subsequent brachial artery ultrasonography. SDB was quantified using the apnea-hypopnea index (AHI) and indexes of overnight desaturation and arousal frequency. Two-dimensional and Doppler-velocity measurements of the brachial artery were obtained at baseline and after 5 minutes of upper-arm cuff occlusion. FMD and PBF were defined as the percentage changes from baseline in brachial artery diameter and flow, respectively. RESULTS: In the entire sample, the AHI was inversely associated with both FMD (r = -0.30, P < .001) and PBF (r = -0.20, P < .001). However, sex-stratified univariate analyses showed that these relationships were exclusive to women. Specifically, FMD was significantly lower in women with an AHI > or = 15 than in women with lower AHI scores (P < .005), with no relationship between AHI and FMD in men. Additionally, PBF decreased significantly with increasing AHI (r = -0.29, P = .010) in women alone. Statistical modeling, adjusting for body mass index, age, and other covariates, similarly showed that SDB severity significantly influenced FMD and PBF, with significant interactions between sex and AHI, reinforcing that the associations between SDB severity and endothelial function were stronger in women than in men. CONCLUSIONS: Moderate levels of SBD are associated with impaired conduit and resistance endothelial function in women. Women with SDB may be more vulnerable to early SDB-related cardiovascular disease than are men.
Adult↗
Whole genome scan for obstructive sleep apnea and obesity in African-American families.
Obstructive sleep apnea (OSA) is a common, chronic disease associated with obesity. OSA and obesity are both prevalent in African Americans, who are also at increased risk for secondary complications. To identify susceptibility loci for OSA, we undertook a 9-centimorgans genome scan in 59 African-American pedigrees ascertained on the basis of either an affected individual with laboratory-confirmed disease or a proband who was a neighborhood control subject. Variance component linkage analysis was performed for the quantitative phenotypes apnea-hypopnea index (AHI) and body mass index. A candidate region on chromosome 8q (logarithm of odds [LOD] = 1.29, p = 0.006) gave the only evidence for linkage to the AHI. Body mass index was linked to multiple regions, most significantly to markers on chromosome 4q (LOD = 2.63, p = 0.0006) and 8q (LOD = 2.56, p = 0.0007). Evidence of linkage to the AHI was only slightly reduced after adjustment for body mass index. After adjustment for the AHI, some of the primary linkages to body mass index were greatly reduced whereas others remained suggestive. Our results suggest that there are both shared and unshared genetic factors underlying susceptibility to OSA and obesity, and that the genetic determinants of obesity in this population may be modulated by apnea severity.
Adolescent↗
Relationship between obstructive sleep apnea and diurnal leptin rhythms.
STUDY OBJECTIVES: Several studies have reported an association between obstructive sleep apnea and leptin, a hormone that influences satiety and body weight. We evaluated the relationship of leptin levels and the overnight change in levels with sleep apnea. DESIGN: Cross-sectional analysis of data from a prospective cohort study. SETTING: Case Western Reserve University General Clinical Research Center. PATIENTS OR PARTICIPANTS: A total of 138 individuals participating in the Cleveland Family Study--59% women, 45% African-American, with mean apnea-hypopnea index (AHI) of 6.9 (range 0-106)--were studied. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Serum leptin was measured at 10:00 pm to 11:00 pm and at 7:00 am to 8:00 am. Leptin levels in both the morning and evening were positively correlated with apnea-hypopnea index (AHI) in age-, sex-, and race-adjusted analyses (P < .0001) but not after additional adjustment for body mass index. The evening/morning leptin ratio, however, was associated with AHI independent of age, sex, race, body mass index, and waist-hip ratio (P = .03). Conversely, AHI was an independent predictor of the leptin ratio (P = .001) and more predictive than arousal index, oxygenation indices, time asleep, or sleep-stage distribution. An AHI > 15 was associated with a 23% increase in leptin ratio. CONCLUSIONS: These findings suggest that sleep apnea may suppress secretion of leptin in the morning. Alternatively, the relative elevation in evening leptin may influence apnea pathogenesis.
Adolescent↗
Variation in childhood asthma among former preterm infants.
OBJECTIVES: The role of in utero and perinatal exposures in modifying asthma risk among children born prematurely was assessed. Study design Former preterm children (n=251) were identified from a birth cohort. Examinations, including lung function testing, were performed at ages 8 to 11 years. Perinatal exposures were ascertained from neonatal medical records. RESULTS: Univariate predictors of asthma included male gender, African American ethnicity, maternal asthma, and birth weight. Asthmatics were less likely to have been small for gestational age (SGA) than nonasthmatics (12.4% vs 22.7%, P=.04) and had more neonatal pulmonary disease. After adjusting for maternal asthma and demographic factors, asthma was associated with chronic lung disease of infancy, neonatal mechanical ventilation and corticosteroid use, and a higher childhood body mass index. Children who were septic postbirth and girls who were SGA were less likely to have asthma (OR for sepsis, 0.2; 95% CI, 0.1-0.6; OR for girls who were SGA compared with girls who were not SGA, 0.05; CI, 0.01-0.34). CONCLUSIONS: Among premature children, female SGA status and neonatal sepsis appear protective relative to the development of childhood asthma. Differential susceptibility to asthma among preterm children may relate to exposures that operate in the in utero and early postnatal environment to accelerate lung development, alter innate immunity, or both.
Asthma↗
Sleep-disordered breathing and cognitive impairment in elderly Japanese-American men.
STUDY OBJECTIVE: To assess the association between sleep-disordered breathing and cognitive functioning in an elderly cohort of Japanese-American men. DESIGN: Cross-sectional study. SETTING: The Honolulu-Asia Aging Study of Sleep Apnea, Oahu, Hawaii. PARTICIPANTS: 718 men between 79 and 97 years of age examined in 1999 and 2000. MEASUREMENTS: Apnea-hypopnea index from in-home overnight polysomnography, performance on the Cognitive Abilities Screening Instrument, body mass index, neck circumference, Epworth Sleepiness Scale, snoring, Center for Epidemiologic Studies Depression 11-item depression scale, physical disability, and history of heart disease, stroke, hypertension, diabetes, and dementia. RESULTS: Less than 30% of the men had no sleep-disordered breathing (apnea-hypopnea index < 5) and nearly one-fifth (19%) had severe sleep-disordered breathing (apnea-hypopnea index > or = 30). Severe sleep-disordered breathing was associated with higher body mass index, habitual snoring, and daytime drowsiness. No association was found between sleep-disordered breathing and cognitive functioning, including measures of memory function, concentration, and attention. CONCLUSIONS: Sleep-disordered breathing was associated with more drowsiness but not with poor performance on standardized cognitive tests used to screen for Alzheimer disease and other dementias in older persons. Because a healthy-participant effect may have contributed to this finding, more extensive cognitive testing may be necessary to reveal more subtle deficits from sleep-disordered breathing.
Aged↗
Incidence of sleep-disordered breathing in an urban adult population: the relative importance of risk factors in the development of sleep-disordered breathing.
CONTEXT: Sleep-disordered breathing (SDB) is both prevalent and associated with serious chronic illness. The incidence of SDB and the effect of risk factors on this incidence are unknown. OBJECTIVE: To determine the 5-year incidence of SDB overall and as influenced by risk factors. DESIGN, SETTING, AND PARTICIPANTS: Of the 1149 participants in the Cleveland Family Study, those aged 18 years or older, from either case or control families, who had 2 in-home sleep studies 5 years apart. The first had to have been performed before June 30, 1997, and had to have normal results (apnea hypopnea index [AHI] <5). Data included questionnaire information on medical and family history, SDB symptoms; measurement of height, weight, blood pressure, waist and hip circumference, and serum cholesterol concentration; and overnight sleep monitoring. MAIN OUTCOME MEASURE: Apnea hypopnea index, defined as number of apneas and hypopneas per hour of sleep. Sleep-disordered breathing was defined by an AHI of at least 10 (mild to moderate) or of at least 15 (moderate). RESULTS: Forty-seven (16%) of 286 eligible participants, (95% confidence interval [CI], 13%-21%) had a second-study AHI of at least 10 and 29 (10%) participants (95% CI, 7%-14%) had a second-study AHI result of at least 15. For the AHI results of at least 15, we estimate that about 2.5% may represent test variability. By ordinal logistic regression analysis, AHI was significantly associated with age (odds ratio [OR] per 10-year increase, 1.79; 95% CI, 1.41-2.27), body mass index (BMI; OR per 1-unit increase, 1.14; 95% CI, 1.10-1.19), sex (OR for men vs women, 4.12; 95% CI, 2.29-7.43), waist-hip ratio (OR per 0.1 unit increase, 1.61; 95% CI, 1.04-2.28), and serum cholesterol concentration (OR per 10-mg/dL [0.25-mmol/L] increase, 1.11; 95% CI, 1.03-1.19). Interactions were noted between age and both sex (P =.003) and BMI (P =.05). The OR for increased AHI per 10-year age increase was 2.41 in women (95% CI, 1.78-3.26) and 1.15 in men (95% CI, 0.78-1.68), with the male vs female OR decreasing from 5.04 (95% CI, 2.19-11.6) at age 30 years to 0.54 (95% CI, 0.15-1.99) at age 60 years. The OR for increased AHI per 1-unit increase in BMI decreased from 1.21 (95% CI, 1.11-1.31) at age 20 years to 1.05 (95% CI, 0.96-1.15) at age 60 years. CONCLUSIONS: The 5-year incidence is about 7.5% for moderately severe SDB and 16% (or less) for mild to moderately severe SDB. Incidence of SDB is influenced independently by age, sex, BMI, waist-hip ratio, and serum cholesterol concentration. Predominance in men diminishes with increasing age, and by age 50 years, incidence rates among men and women are similar. The effect of BMI also decreases with age and may be negligible at age 60 years.
Adult↗
Decreased quality of life associated with obesity in school-aged children.
OBJECTIVES: To examine the association between health-related quality of life and body mass index (BMI) in preadolescent school-aged children and to provide the possible risk factors among participant characteristics, BMI status, and health-related quality of life. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional analysis of 371 (50% female; 32% minority) children from a community-based sample of 8- to 11-year-olds participating in an ongoing cohort study, excluding those who had sleep apnea or who were born prematurely. Using BMI percentiles for age and sex, 17.5% of the children were considered overweight (BMI > or =95th percentile), 12.4% were at risk for overweight (BMI 85th-94th percentile), 8.1% were relatively underweight (BMI <20th percentile), and the remaining 62.0% were of normal weight (BMI 20th-84th percentile). MAIN OUTCOME MEASURES: Health-related quality-of-life scores as determined by the Child Health Questionnaire-Parent Form 50, dichotomized into the bottom quartile or decile. RESULTS: After adjustment for covariates (host factors and health status measurements), overweight children compared with normal weight children scored lower on the Psychosocial Health Summary (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.1-3.6) and on subscales measuring self-esteem (OR, 3.5; 95% CI, 1.9-6.3), physical functioning (OR, 2.8; 95% CI, 1.7-6.8), and effect on the parent's emotional well-being (OR, 2.0; 95% CI, 1.1-3.6). Compared with the normal weight group, children who are at risk for overweight scored significantly lower for physical functioning. CONCLUSION: Overweight children have an increased odds of low scores for several health-related quality-of-life domains, suggesting the importance in considering such dimensions in programs aimed at further understanding obesity in children.
Asthma↗
Development and validation of school-based asthma and allergy screening instruments for parents and students.
BACKGROUND: The increasing morbidity attributable to asthma among school-aged children suggests the potential utility of school-based asthma screening programs. OBJECTIVE: We report our efforts to develop and validate culturally sensitive and clinically useful screening questionnaires (parent and child versions) for asthma and allergies among urban US school children. METHODS: Instrument development was accomplished through literature review, expert medical and child developmental input, focus group feedback, and a rigorous trial of the instruments in a public school setting. Questionnaires were distributed to 2,800 children and their families in an urban public school system (grades kindergarten through 6). Validity was evaluated by blinded comparison of results against a standardized clinical evaluation in 107 children, with final designations determined by an expert panel. RESULTS: Questionnaires pertaining to 2,083 children were returned (participation rate of 74%). A moderate level of agreement was observed between parent and student questionnaire responses (r values = 0.36 to 0.50; P values < 0.001). The highest frequency of asthma-like symptoms was reported for African-American boys and the lowest for Caucasian girls. The items from the parent questionnaire that best predicted asthma were "breathing problems" (occurring rarely or more; odds ratio 12.8; 95% confidence interval, 4.5 to 36.1) and "problems coughing" (sometimes or more; odds ratio 9.7; 95% confidence interval, 3.6 to 26.5). Considering the presence of cough (sometimes or more) and/or breathing problem (rarely or more) yielded a sensitivity of 80%; a specificity of 75%, a positive predictive value of 50%, and a negative predictive value of 92%. Similar levels of prediction were observed for the items "trouble breathing" and "noisy breathing" as directly reported by the students. Allergic rhinitis was best predicted by report of a runny/stuffy no se (sometimes or more; sensitivity of 83%, specificity of 61%). Allergic conjunctivitis was best predicted by "itchy eyes." CONCLUSIONS: Administration of a school-based questionnaire is feasible, with a high response rate and excellent internal consistency. A high sensitivity and acceptable specificity was achieved by using one to two questions for asthma, allergic rhinitis, and allergic conjunctivitis. Among the children in grades 2 or above, comparable levels of prediction could be achieved with the student or parent version.
Adolescent↗
Prevalence and risk factors for sleep-disordered breathing in 8- to 11-year-old children: association with race and prematurity.
OBJECTIVES: To evaluate the extent to which sleep-disordered breathing (SDB) varies with putative demographic and medical risk factors and to estimate the prevalence of undiagnosed SDB. STUDY DESIGN: Prospective, cross-sectional study in a population-based cohort of 850 children (41% black, 46% preterm), 8 to 11 years of age. Participants' caretakers completed questionnaires about health and sleep. Children underwent overnight in-home cardiorespiratory recordings of airflow, respiratory effort, oximetry, and electrocardiography. SDB was identified by respiratory disturbance indices commonly applied in clinical practice. Risk factors were estimated by logistic regression. Prevalence was derived from cohort-specific estimates with birth weights from US live births data. RESULTS: Using the most inclusive definition, SDB was detected in 40 (4.7%) participants, with prevalence varying widely across population subsets. Depending on the definition used, SDB was 4 to 6 times more likely in black children compared with white children and almost 3 to 5 times more likely in former preterm compared with term children. The estimated population prevalence of SDB was 2.2% (95% CI, 1.2%, 3.2%). CONCLUSIONS: SDB is a relatively common condition in 8- to 11-year-old children. Potentially vulnerable subgroups, black children, and former preterm infants, are at increased risk.
Cardiovascular System↗
Predictors of longitudinal change in sleep-disordered breathing in a nonclinic population.
STUDY OBJECTIVES: To quantify and identify the determinants of the 5-year change in the respiratory disturbance index (RDI). DESIGN: Longitudinal cohort study (Cleveland Family Study). Multivariate analyses were used to quantify baseline RDI and RDI change. SETTING: Community-based study. PARTICIPANTS: 486 cohort members (62% from families of probands with sleep-disordered breathing [SDB])--mean age 31.6 +/- 17.9 (SD) years, 60% female, 21% Black ethnicity--who underwent 2 assessments over 5.3 +/- 0.9 (SD) years. INTERVENTIONS: NA. MEASUREMENTS: The RDI was measured twice over approximately 5 years with in-home monitoring. Symptoms and medical histories were obtained from standardized questionnaires, and weight, height, and blood pressure were measured. RESULTS: The prevalence of SDB (defined by a RDI > or = 15), increased from 13.7% to 23.4% (P < 0.01) in men and from 8.3% to 11.4% (P = 0.13) in females. Baseline and follow-up mean RDIs were 6.0 +/- 10.0 and 8.6 +/- 14.3; both were higher in older individuals, in men, and in those with a higher body mass index. Median 5-year change in RDI varied nonlinearly with age (-0.1, 1.1, 2.3, and 0.9, for those < 18, 19-40, 41-54, and > or = 55 years, respectively) and obesity (2.8 vs -0.1, for the top versus lowest body mass index quartile). The effects of changing weight and aging varied in population subgroups. At any given age and weight, the RDI increased less in women. CONCLUSIONS: Longitudinal change in the RDI varies nonuniformly with age, sex, and weight. Older heavier men may experience the highest rate of increase in RDI over time and, thus, may benefit most from prospective monitoring.
Adult↗
Health-related quality of life and sleep-disordered breathing in children.
STUDY OBJECTIVES: To assess the extent to which sleep-disordered breathing (SDB) is associated with impairment of health-related quality of life (HRQOL) in children DESIGN: Observational study of pediatric participants in a longitudinal genetic-epidemiologic cohort study of SDB. SETTING: Community-based; studies conducted at participants' homes PARTICIPANTS: 298 children, aged 11.1 years +/- 3.5 SD; 54% females; 61% African-American or Other; 81% with a family member identified with laboratory-confirmed SDB. INTERVENTIONS: Not applicable MEASUREMENTS AND RESULTS: The HRQOL was assessed with the Child Health Questionnaire (CHQ-PF50), a 50-item parent-completed form that measures 14 multidimensional health concepts. Sleep-disordered breathing (SDB) was assessed with ovemight in-home monitoring that recorded nasal-oral airflow, pulse oximetry, chest-wall impedance, and heart rate. Using logistic regression analyses, each CHQ scale outcome was analyzed independently for the effect of SDB, adjusting for other potential confounding variables and for family-correlated data. Significant differences in overall physical health and complaints of bodily pain were observed in children with generally mild levels of SDB. Relationships persisted after adjustment for age, gender, ethnicity, obesity, and asthma. CONCLUSIONS: SDB in children is associated with measurably lower levels of specific dimensions of HRQOL in children. Decrements in HRQOL are measurable even for children with mild SDB, with increasing effects observed with more severe SDB.
Adolescent↗
Utility of noninvasive pharyngometry in epidemiologic studies of childhood sleep-disordered breathing.
Measurement of pharyngeal dimensions may contribute to the characterization of anatomic risk factors for sleep-disordered breathing (SDB) in children. Acoustic pharyngometry, a noninvasive method, has been used successfully in adults, but application in children has been limited. We sought to evaluate the feasibility and utility of this technique in children, including assessment of the variation of pharyngeal measurements with height, sex, ethnicity, prematurity, and indices of SDB. Subjects were drawn from a large, community-based cohort of children of age 8-11 years. Demographic, morphologic, and sleep-related information were collected via standard questionnaires, direct measurement, and home cardiorespiratory monitoring during sleep. Pharyngeal dimensions were assessed in 203 children using acoustic pharyngometry performed with an optimized mouthpiece. In this sample, the coefficient of variation of minimum pharyngeal cross-sectional area (CSA) and mean CSA were similar to those in adults (8.0 and 11.1%, respectively). The minimum CSA, but not mean CSA, was significantly reduced in preterm children, habitual snorers, and children with SDB relative to unaffected children. Thus, minimum CSA is a useful measure for evaluating SDB risk factors in preadolescent children.
Acoustics↗
Identification of sleep-disordered breathing in children: variation with event definition.
STUDY OBJECTIVES: To determine the effect of varying approaches to the measurement of the respiratory disturbance index (RDI) on identification of sleep disordered breathing (SDB) in children. DESIGN: Cross-sectional study of SDB in a well-characterized birth cohort (stratified for term and preterm birth) participating in longitudinal studies of cognition and behavior. SETTING: Community-based; overnight studies conducted in participant's homes. PARTICIPANTS: 433 children, ages 8-11 years, un-referred for clinical assessment of SDB. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Participants underwent unattended overnight in-home recording of respiratory inductance plethysmography, pulse oximetry, body position, and heart rate. The relationships among RDIs derived from various definitions of apnea and hypopneas and thresholds for frequency of events were assessed. Median RDI varied by more than 20-fold for definitions using the more liberal criteria for event definition (all respiratory events; i.e., central or obstructive events and hypopneas with no requirement for associated desaturation) to the most conservative definition (using obstructive apneas only or obstructive apnea and hypopneas requiring a 5% associated desaturation). Prevalence estimates for SDB based on RDIs that included central apneas were 40% to 140% higher than those that excluded central apneas. CONCLUSIONS: Different approaches for quantifying RDI contribute to substantial variability in identification and classification of SDB in children and will lead to discrepant estimates of its presence and severity.
Child↗