Diane S. Lauderdale

Self-reported and measured sleep duration: how similar are they?

Background: Recent epidemiologic studies have found that self-reported duration of sleep is associated with obesity, diabetes, hypertension, and mortality. The extent to which self reports of sleep duration are similar to objective measures and whether individual characteristics influence the degree of similarity are not known. Methods: Eligible participants at the Chicago site of the Coronary Artery Risk Development in Young Adults Study were invited to participate in a 2003–2005 ancillary sleep study; 82% (n = 669) agreed. Sleep measurements collected in 2 waves included 3 days each of wrist actigraphy, a sleep log, and questions about usual sleep duration. We estimate the average difference and correlation between subjectively and objectively measured sleep by using errors-in-variables regression models. Results: Average measured sleep was 6 hours, whereas the average from subjective reports was 6.8 hours. Subjective reports increased on average by 34 minutes for each additional hour of measured sleep. Overall, the correlation between reported and measured sleep duration was 0.47. Our model suggests that persons sleeping 5 hours over-reported their sleep duration by 1.2 hours, and those sleeping 7 hours over-reported by 0.4 hours. The correlations and average differences between self-reports and measured sleep varied by health, sociodemographic, and sleep characteristics. Conclusion: In a population-based sample of middle-aged adults, subjective reports of habitual sleep are moderately correlated with actigraph-measured sleep, but are biased by systematic over-reporting. The true associations between sleep duration and health may differ from previously reported associations between self-reported sleep and health.Recent epidemiologic studies have found that sleep duration is associated with obesity, diabetes, hypertension and mortality. These studies have used self-reported habitual sleep duration, which has not been well validated. We model the extent to which self-reported habitual sleep reflects average objectively measured sleep. Eligible participants at the Chicago site of Coronary Artery Risk Development in Young Adults Study were invited to participate in a 2003-2004 ancillary sleep study; 82% (n=669) agreed. Sleep measurements collected in two waves included: 3-days of wrist actigraphy, a sleep log, and standard questions about usual sleep duration. Average measured sleep was 6 hours, and subjective reports averaged 0.80 hours longer than measured sleep. Subjective reports were not well calibrated, increasing on average by 31 minutes for each additional hour of measured sleep. Our model suggests that persons sleeping 5 and 7 hours over-reported, on average, by 1.3 and 0.3 hours respectively. Overall, there was a correlation of 0.45 between reported and measured sleep duration. The extent of overestimation, calibration and correlation varied by personal and sleep characteristics. Although asking about sleep duration seems uncomplicated, the correlation between self-reported and objectively-measured sleep in this population was moderate and systematically biased.

Exercise Capacity and the Risk of Death in Women The St James Women Take Heart Project

Background—Cardiovascular disease is the leading cause of death among women and accounts for more than half of their deaths. Women have been underrepresented in most studies of cardiovascular disease. Reduced physical fitness has been shown to increase the risk of death in men. Exercise capacity measured by exercise stress test is an objective measure of physical fitness. The hypothesis that reduced exercise capacity is associated with an increased risk of death was investigated in a cohort of 5721 asymptomatic women who underwent baseline examinations in 1992. Methods and Results—Information collected at baseline included medical and family history, demographic characteristics, physical examination, and symptom-limited stress ECG, using the Bruce protocol. Exercise capacity was measured in metabolic equivalents (MET). Nonfasting blood was analyzed at baseline. A National Death Index search was performed to identify all-cause death and date of death up to the end of 2000. The mean age of participants at baseline was 52±11 years. Framingham Risk Score–adjusted hazards ratios (with 95% CI) of death associated with MET levels of <5, 5 to 8, and >8 were 3.1 (2.0 to 4.7), 1.9 (1.3 to 2.9), and 1.00, respectively. The Framingham Risk Score–adjusted mortality risk decreased by 17% for every 1-MET increase. Conclusions—This is the largest cohort of asymptomatic women studied in this context over the longest period of follow-up. This study confirms that exercise capacity is an independent predictor of death in asymptomatic women, greater than what has been previously established among men. The implications for clinical practice and health care policy are far reaching.

Measuring culture: a critical review of acculturation and health in Asian immigrant populations

The number of studies examining how acculturation affects the health of Asian immigrants has increased in recent years. The proliferation of studies reflects the growing size and heterogeneity of Asian immigrant populations in the United States, Canada, Australia, New Zealand, and the United Kingdom. This paper compares various approaches to acculturation within the health literature on Asian immigrants by reviewing the literature in three-health domains (1) mental health (2) physical health and (3) health services use. The review critically examines the conceptualizations and measures of acculturation in these three domains and presents major findings. We observe that measurement difficulties posed by the experiences of heterogeneous Asian groups compound theoretical and disciplinary disparities between acculturation instruments. The extent to which conceptual and methodological critiques of acculturation studies in Hispanic populations apply to studies of Asian populations is also discussed. The critical review thus provides insights into the diverse ways that the relationship between culture and health is measured in this complicated and growing literature.

Improving In-Hospital Cardiac Arrest Process and Outcomes With Performance Debriefing

BACKGROUND Recent investigations have documented poor cardiopulmonary resuscitation (CPR) performance in clinical practice. We hypothesized that a debriefing intervention using CPR quality data from actual in-hospital cardiac arrests (resuscitation with actual performance integrated debriefing [RAPID]) would improve CPR performance and initial patient survival. METHODS Internal medicine residents at a university hospital attended weekly debriefing sessions of the prior weeks resuscitations, between March 2006 and February 2007, reviewing CPR performance transcripts obtained from a CPR-sensing and feedback-enabled defibrillator. Objective metrics of CPR performance and initial return of spontaneous circulation were compared with a historical cohort in which a similar feedback-delivering defibrillator was used but without RAPID. RESULTS Cardiopulmonary resuscitation quality and outcome data from 123 patients resuscitated during the intervention period were compared with 101 patients in the baseline cohort. Compared with the control period, the mean (SD) ventilation rate decreased (13 [7]/min vs 18 [8]/min; P < .001) and compression depth increased (50 [10] vs 44 [10] mm; P = .001), among other CPR improvements. These changes correlated with an increase in the rate of return of spontaneous circulation in the RAPID group (59.4% vs 44.6%; P = .03) but no change in survival to discharge (7.4% vs 8.9%; P = .69). CONCLUSIONS The combination of RAPID and real-time audiovisual feedback improved CPR quality compared with the use of feedback alone and was associated with an increased rate of return of spontaneous circulation. Cardiopulmonary resuscitation sensing and recording devices allow for methods of debriefing that were previously available only for simulation-based education; such methods have the potential to fundamentally alter resuscitation training and improve patient outcomes. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00228293.

Body mass index in a US national sample of Asian Americans : effects of nativity, years since immigration and socioeconomic status

OBJECTIVE: To examine body mass index (BMI) and the proportion overweight and obese among adults age 18–59 in the six largest Asian American ethnic groups (Chinese, Filipino, Asian Indian, Japanese, Korean, Vietnamese), and investigate whether BMI varies by nativity (foreign- vs native-born), years in US, or socioeconomic status.DESIGN: Cross-sectional interview data were pooled from the 1992–1995 National Health Interview Survey (NHIS).SUBJECTS: 254,153 persons aged 18–59 included in the 1992–1995 NHIS. Sample sizes range from 816 to 1940 for each of six Asian American ethnic groups.MEASUREMENTS: Self-reported height and weight used to calculate BMI and classify individuals as overweight (BMI≥25 kg/m2) or obese (BMI≥30 kg/m2), age, sex, years in the US, household income and household size.RESULTS: For men, the percentage overweight ranges from 17% of Vietnamese to 42% of Japanese, while the total male population is 57% overweight. For women, the percentage overweight ranges from 9% of Vietnamese and Chinese to 25% of Asian Indians, while the total female population is 38% overweight. The percentage of Asian Americans classified as obese is very low. Adjusted for age and ethnicity, the odds ratio for obese is 3.5 for women and 4.0 for men for US - vs foreign-born. Among the foreign-born, more years in the US is associated with higher risk of being overweight or obese. The association between household income for women is similar for US-born Asian Americans and Whites and Blacks, but is much weaker for foreign-born Asian Americans.CONCLUSIONS: While these data find low proportions of Asian Americans overweight at present, they also imply the proportion will increase with more US-born Asian Americans and longer duration in the US.

Impact of Interpreter Services on Delivery of Health Care to Limited–English‐proficient Patients

OBJECTIVE: To determine whether professional interpreter services increase the delivery of health care to limited-English-proficient patients.DESIGN: Two-year retrospective cohort study during which professional interpreter services for Portuguese and Spanish-speaking patients were instituted between years one and two. Preventive and clinical service information was extracted from computerized medical records.SETTING: A large HMO in New England.PARTICIPANTS: A total of 4,380 adults continuously enrolled in a staff model health maintenance organization for the two years of the study, who either used the comprehensive interpreter services (interpreter service group [ISG]; N=327) or were randomly selected into a 10% comparison group of all other eligible adults (comparison group [CG]; N=4,053).MEASUREMENTS AND MAIN RESULTS: The measures were change in receipt of clinical services and preventive service use. Clinical service use and receipt of preventive services increased in both groups from year one to year two. Clinical service use increased significantly in the ISG compared to the CG for office visits (1.80 vs 0.70; P<.01), prescriptions written (1.76 vs 0.53; P<.01), and prescriptions filled (2.33 vs 0.86; P<.01). Rectal examinations increased significantly more in the ISG compared to the CG (0.26 vs 0.02; P=.05) and disparities in rates of fecal occult blood testing, rectal exams, and flu immunization between Portuguese and Spanish-speaking patients and a comparison group were significantly reduced after the implementation of professional interpreter services.CONCLUSION: Professional interpreter services can increase delivery of health care to limited-English-speaking patients.

Short sleep duration and incident coronary artery calcification

CONTEXT Coronary artery calcification is a subclinical predictor of coronary heart disease. Recent studies have found that sleep duration is correlated with established risk factors for calcification including glucose regulation, blood pressure, sex, age, education, and body mass index. OBJECTIVE To determine whether objective and subjective measures of sleep duration and quality are associated with incidence of calcification over 5 years and whether calcification risk factors mediate the association. DESIGN, SETTING, AND PARTICIPANTS Observational cohort of home monitoring in a healthy middle-aged population of 495 participants from the Coronary Artery Risk Development in Young Adults (CARDIA) cohort Chicago site (black and white men and women aged 35-47 years at year 15 of the study in 2000-2001 with follow-up data at year 20 in 2005-2006). Potential confounders (age, sex, race, education, apnea risk, smoking status) and mediators (lipids, blood pressure, body mass index, diabetes, inflammatory markers, alcohol consumption, depression, hostility, self-reported medical conditions) were measured at both baseline and follow-up. Sleep metrics (wrist actigraphy measured duration and fragmentation, daytime sleepiness, overall quality, self-reported duration) were examined for association with incident calcification. Participants had no detectable calcification at baseline. MAIN OUTCOME MEASURE Coronary artery calcification was measured by computed tomography in 2000-2001 and 2005-2006 and incidence of new calcification over that time was the primary outcome. RESULTS Five-year calcification incidence was 12.3% (n = 61). Longer measured sleep duration was significantly associated with reduced calcification incidence (adjusted odds ratio, 0.67 per hour [95% confidence interval, 0.49-0.91 per hour]; P = .01). No potential mediators appreciably altered the magnitude or significance of sleep (adjusted odds ratio estimates ranged from 0.64 to 0.68 per sleep hour; maximum P = .02). Alternative sleep metrics were not significantly associated with calcification. CONCLUSION Longer measured sleep is associated with lower calcification incidence independent of examined potential mediators and confounders.

Association between sleep and blood pressure in midlife: the CARDIA sleep study.

BACKGROUND Epidemiological studies have reported an association between self-reported short sleep duration and high blood pressure (BP). Our objective was to examine both cross-sectional and longitudinal associations between objectively measured sleep and BP. METHODS This study is ancillary to the Coronary Artery Risk Development in Young Adults (CARDIA) cohort study. Blood pressure was measured in 2000 and 2001 and in 2005 and 2006. Sleep was measured twice using wrist actigraphy for 3 consecutive days between 2003 and 2005. Sleep duration and sleep maintenance (a component of sleep quality) were calculated. Analyses included 578 African Americans and whites aged 33 to 45 years at baseline. Outcome measures were systolic BP (SBP) and diastolic BP (DBP) levels, 5-year change in BP, and incident hypertension. RESULTS After we excluded the patients who were taking antihypertensive medications and adjusted for age, race, and sex, shorter sleep duration and lower sleep maintenance predicted significantly higher SBP and DBP levels cross-sectionally as well as more adverse changes in SBP and DBP levels over 5 years (all P < .05). Short sleep duration also predicted significantly increased odds of incident hypertension (odds ratio, 1.37; 95% confidence interval, 1.05-1.78). Adjustment for 16 additional covariates, including snoring and daytime sleepiness, slightly attenuated the associations between sleep and BP. Sleep duration appeared to mediate the difference between African Americans and whites in DBP change over time (P = .02). CONCLUSION Reduced sleep duration and consolidation predicted higher BP levels and adverse changes in BP, suggesting the need for studies to investigate whether interventions to optimize sleep may reduce BP.

Birth Outcomes for Arabic-Named Women in California Before and After September 11

Persons who were perceived to be Arabs experienced a period of increased harassment, violence, and workplace discrimination in the United States in the weeks immediately following September 11, 2001. Drawing on prior studies that have hypothesized that experiences of discrimination increase the risk of preterm birth and low birth weight, this study explores whether there was an effect on birth outcomes for pregnant women of Arab descent. California birth certificate data are used to determine the relative risk of poor birth outcomes by race, ethnicity, and nativity for women who gave birth in the six months following September 2001, compared with the same six calendar months one year earlier. The relative risk of poor birth outcomes was significantly elevated for Arabic-named women and not for any of the other groups.

Asian American ethnic identification by surname

Few data sources include ethnicity-levelclassification for Asian Americans. However, it isoften more informative to study the ethnic groupsseparately than to use an aggregate Asian Americancategory, because of differences in immigrationhistory, socioeconomic status, health, and culture. Many types of records that include surnames of personsoffer the potential for inferential ethnicclassification. This paper describes the developmentof surname lists for six major Asian American ethnicgroups: Chinese, Japanese, Filipino, Korean, AsianIndian, and Vietnamese. The lists were based on SocialSecurity Administration records that include countryof birth. After they were compiled, the lists wereevaluated using an independent file of census records.The surname lists have a variety of applications forresearchers: identification of individuals to targetfor study participation; inference of ethnicity indata sources lacking ethnic detail; andcharacterization of the ethnic composition of apopulation.