@article {782, title = {Sleep-disordered breathing is not associated with the presence of retinal microvascular abnormalities: the Sleep Heart Health Study.}, journal = {Sleep}, volume = {27}, year = {2004}, month = {2004 May 01}, pages = {467-73}, abstract = {

STUDY OBJECTIVE: Sleep apnea and milder forms of sleep-disordered breathing (SDB) have been associated with overt clinical cardiovascular disease, but it is unknown whether SDB is associated with arterial microvascular pathology. We examined the relation between SDB and retinal microvascular abnormalities.

DESIGN: Cross-sectional study.

PARTICIPANTS: Subjects were 2,927 men and women, aged 51 to 97 years, who participated in the Sleep Heart Health Study and had retinal photographs taken within approximately 3 years of overnight, unattended, at-home polysomnography.

MEASUREMENTS AND RESULTS: A respiratory disturbance index (RDI), calculated as the average number of apneas and hypopneas per hour of sleep, was used as an indicator of SDB in analysis. The overall prevalence of retinopathy was slightly higher in people with higher RDI values (5.4\%, 4.9\%, 8.6\%, and 7.6\%, respectively, in increasing quartiles of RDI), but after adjustment for age, body-mass index, hypertension, diabetes, and other factors, the presence of retinopathy was not associated with SDB. With the possible exceptions of microaneurysms and generalized arteriolar narrowing, as measured by lower arteriole-to-venule ratio, specific retinal abnormalities were not associated consistently with the RDI. Relative to the first quartile of RDI, the adjusted odds ratios (95\% confidence interval) for the presence of microaneurysm in the second, third, and fourth quartiles of RDI were 1.05 (0.44-2.55), 1.97 (0.89-4.37), and 1.79 (0.78-4.10), respectively. An increase of RDI from 0 to 10 was associated with a predicted decrease in arteriole-to-venule ratio of 0.01. Results were similar when analyses were conducted in normotensive and nondiabetic persons separately.

CONCLUSIONS: These data do not demonstrate a notable relation between SDB and retinal abnormalities. However, since this is the first investigation of a link between retinopathy and SDB, similar studies should be conducted in other population samples to demonstrate either consistency or inconsistency of our findings across studies.

}, keywords = {Aged, Aged, 80 and over, Body Mass Index, Coronary Disease, Cross-Sectional Studies, Female, Humans, Hypoxia, Middle Aged, Polysomnography, Positive-Pressure Respiration, Retina, Retinal Vessels, Sleep Apnea Syndromes}, issn = {0161-8105}, doi = {10.1093/sleep/27.3.467}, author = {Boland, Lori L and Shahar, Eyal and Wong, Tien Y and Klein, Ronald and Punjabi, Naresh and Robbins, John A and Newman, Anne B} } @article {1546, title = {Bootstrap-based inference on the difference in the means of two correlated functional processes.}, journal = {Stat Med}, volume = {31}, year = {2012}, month = {2012 Nov 20}, pages = {3223-40}, abstract = {

We propose nonparametric inference methods on the mean difference between two correlated functional processes. We compare methods that (1) incorporate different levels of smoothing of the mean and covariance; (2) preserve the sampling design; and (3) use parametric and nonparametric estimation of the mean functions. We apply our method to estimating the mean difference between average normalized δ power of sleep electroencephalograms for 51 subjects with severe sleep apnea and 51 matched controls in the first 4 h after sleep onset. We obtain data from the Sleep Heart Health Study, the largest community cohort study of sleep. Although methods are applied to a single case study, they can be applied to a large number of studies that have correlated functional data.

}, keywords = {Biostatistics, Cohort Studies, Confidence Intervals, Humans, Models, Statistical, Sleep Apnea Syndromes, Statistics, Nonparametric}, issn = {1097-0258}, doi = {10.1002/sim.5439}, author = {Crainiceanu, Ciprian M and Staicu, Ana-Maria and Ray, Shubankar and Punjabi, Naresh} }