Laurel Finn

Nasal obstruction as a risk factor for sleep-disordered breathing

Nasal obstruction frequently has been associated with sleep-disordered breathing as a potential etiologic factor. Nasal obstruction results in pathologic changes in airflow velocity and resistance. Experimentally produced nasal obstruction increases resistance and leads to sleep-disordered breathing events, including apnea, hypopnea, and snoring. Clinical research examining the correlation between nasal obstruction and sleep-disordered breathing is limited, especially in regard to patients with conditions that increase nasal resistance, such as rhinitis and sinusitis. To further identify risk factors for sleep-disordered breathing, the role of chronic and acute nasal congestion was investigated in a population-based sample. Data on nasal congestion history and sleep problems were obtained by questionnaire (n = 4927) and by objective inlaboratory measurement (n = 911). Participants who often or almost always experienced nighttime symptoms of rhinitis (5 or more nights a month) were significantly (p < 0.0001) more likely to report habitual snoring (3 to 7 nights a week), chronic excessive daytime sleepiness, or chronic nonrestorative sleep than were those who rarely or never had symptoms. Habitual snorers had significantly (p < 0.02) lower air flow than nonsnorers, although a linear relation between decreased airflow and sleep-disordered breathing severity did not exist. Participants who reported nasal congestion due to allergy were 1.8 times more likely to have moderate to severe sleep-disordered breathing than were those without nasal congestion due to allergy. Men and women with nasal obstruction, especially chronic nighttime symptoms of rhinitis, are significantly more likely to be habitual snorers, and a proportion also may have frequent episodes of apnea and hypopnea, indicative of severe sleep-disordered breathing. Because allergic rhinitis is a common cause of nasal obstruction and it is a modifiable risk factor, further study of this association is warranted.

The gender bias in sleep apnea diagnosis. Are women missed because they have different symptoms

BACKGROUND Population-based studies have shown that sleep apnea is underdiagnosed in women, relative to men. One hypothesis for this gender bias is that women with sleep apnea are missed because clinical guidelines for the evaluation and diagnosis of sleep apnea, established primarily on men, are not valid for women. In this investigation, data from the Wisconsin Sleep Cohort Study, a community-based study of the natural history of sleep apnea, were used to determine whether women with sleep apnea have unique symptoms or complaints. METHODS The sample comprised 551 men and 388 women, none of whom had ever been given a diagnosis of sleep apnea. Data on typical sleep apnea symptoms and other factors were obtained by interview and survey. Sleep apnea status was determined from the frequency of apneic and hypopneic events during sleep as recorded by in-laboratory, whole-night polysomnography. The sensitivity and relative predictive power of each symptom or factor for sleep apnea at different severity levels were calculated and compared by gender. RESULTS Regardless of severity level, women with sleep apnea did not report symptoms that differed significantly from those of men with the same level of sleep apnea. For men and women, snoring was the most sensitive and strongest predictor of sleep apnea. CONCLUSIONS Current clinical indications for sleep apnea evaluation are as appropriate for women as they are for men. Other reasons for the gender disparity in sleep apnea diagnosis, including the possibility that health care providers disregard typical symptoms in women, should be pursued.

Sleep-disordered Breathing and Cancer Mortality

RATIONALE Sleep-disordered breathing (SDB) has been associated with total and cardiovascular mortality, but an association with cancer mortality has not been studied. Results from in vitro and animal studies suggest that intermittent hypoxia promotes cancer tumor growth. OBJECTIVES The goal of the present study was to examine whether SDB is associated with cancer mortality in a community-based sample. METHODS We used 22-year mortality follow-up data from the Wisconsin Sleep Cohort sample (n = 1,522). SDB was assessed at baseline with full polysomnography. SDB was categorized using the apnea-hypopnea index (AHI) and the hypoxemia index (percent sleep time below 90% oxyhemoglobin saturation). The hazards of cancer mortality across levels of SDB severity were compared using crude and multivariate analyses. MEASUREMENTS AND MAIN RESULTS Adjusting for age, sex, body mass index, and smoking, SDB was associated with total and cancer mortality in a dose-response fashion. Compared with normal subjects, the adjusted relative hazards of cancer mortality were 1.1 (95% confidence interval [CI], 0.5-2.7) for mild SDB (AHI, 5-14.9), 2.0 (95% CI, 0.7-5.5) for moderate SDB (AHI, 15-29.9), and 4.8 (95% CI, 1.7-13.2) for severe SDB (AHI ≥ 30) (P-trend = 0.0052). For categories of increasing severity of the hypoxemia index, the corresponding relative hazards were 1.6 (95% CI, 0.6-4.4), 2.9 (95% CI, 0.9-9.8), and 8.6 (95% CI, 2.6-28.7). CONCLUSIONS Our study suggests that baseline SDB is associated with increased cancer mortality in a community-based sample. Future studies that replicate our findings and look at the association between sleep apnea and survival after cancer diagnosis are needed.

Epidemiological insights into the public health burden of sleep disordered breathing: sex differences in survival among sleep clinic patients

Recognition that sleep disordered breathing (SDB) is prevalent but largely undiagnosed in adults has prompted the needs to assess the public health burden of this disorder and devise appropriate prevention and intervention strategies.1 2 Before this can be accomplished, both population and clinic-based epidemiology studies are required to understand the natural history, risk factors and adverse health sequelae of this disorder, and to determine what severity levels are of clinical and public health significance. In this report, epidemiological advances and research needs are briefly summarised. In the second part of this paper we focus on the need for epidemiological research into sex differences in the natural history of SDB and present new findings that suggest women with SDB may have poorer survival than men. Although prevalence estimates of SDB vary according to definitions and methods of measurement, there is general agreement among the most rigorous studies that the prevalence of SDB meeting clinical criteria for sleep apnoea syndrome is in the range of 2–4%.3 In the largest population based study conducted with in-laboratory polysomnography, the prevalence of SDB in middle aged adults in the USA based on lesser severity—for example, an apnoea/hypopnoea index (AHI) of 5 or more—has been estimated at 9% for women and 24% for men.4 Other studies conducted elsewhere in the western world have yielded similar estimates.5 In addition to establishing the high prevalence of SDB, these population-based studies have shown, as is evident in the preceding prevalence estimate, that this is not a disease predominantly of men. Furthermore, women with SDB have been shown to have the same symptoms, risk factors, and health correlates as men.6 The discrepancy between the ratio of men to women with SDB in clinic patient populations (8:1) and in the general population (2–3:1) has underscored the …

Prospective associations of insomnia markers and symptoms with depression.

Whether insomnia, a known correlate of depression, predicts depression longitudinally warrants elucidation. The authors examined 555 Wisconsin Sleep Cohort Study participants aged 33-71 years without baseline depression or antidepressant use who completed baseline and follow-up overnight polysomnography and had complete questionnaire-based data on insomnia and depression for 1998-2006. Using Poisson regression, they estimated relative risks for depression (Zung scale score > or =50) at 4-year (average) follow-up according to baseline insomnia symptoms and polysomnographic markers. Twenty-six participants (4.7%) developed depression by follow-up. Having 3-4 insomnia symptoms versus none predicted depression risk (age-, sex-, and comorbidity-adjusted relative risk (RR) = 3.2, 95% confidence interval: 1.1, 9.6). After multiple adjustments, frequent difficulty falling asleep (RR = 5.3, 95% confidence interval: 1.1, 27.9) and polysomnographically assessed (upper or lower quartiles) sleep latency, continuity, and duration (RRs = 2.2-4.7; Ps < or = 0.05) predicted depression. Graded trends (P-trend < or = 0.05) were observed with increasing number of symptoms, difficulty falling asleep, and difficulty returning to sleep. Given the small number of events using Zung > or =50 (depression cutpoint), a limitation that may bias multivariable estimates, continuous depression scores were analyzed; mean values were largely consistent with dichotomous findings. Insomnia symptoms or markers increased depression risk 2.2- to 5.3-fold. These results support prior findings based on self-reported insomnia and may extend similar conclusions to objective markers. Heightened recognition and treatment of insomnia may prevent subsequent depression.

Dissociation of Obstructive Sleep Apnea From Hypersomnolence and Obesity in Patients With Stroke

Background and Purpose— Obstructive sleep apnea (OSA) is seldom considered in the diagnostic investigation in the poststroke period although it is a stroke risk factor and has adverse prognostic implications after stroke. One reason might be that widely used clinical criteria for detection of OSA in the general community are not applicable in patients with stroke. We hypothesized that patients with stroke report less sleepiness and are less obese than subjects from a community sample with the same severity of OSA. Methods— We performed polysomnography in 96 consecutive patients with stroke admitted to a stroke rehabilitation unit and in a community sample of 1093 subjects without a history of stroke. We compared the degrees of subjective sleepiness assessed by the Epworth Sleepiness Scale and body mass index between the 2 samples according to OSA categories assessed by the frequency of apneas and hypopneas per hour of sleep (<5, no OSA; 5 to <15 mild OSA; and ≥15, moderate to severe OSA). Results— Compared with the community sample, patients with stroke with OSA had significantly lower Epworth Sleepiness Scale scores and body mass index for mild OSA (Epworth Sleepiness Scale 9.3±0.3 versus 5.6±0.5, P<0.001 and body mass index 33.1±0.5 versus 28.5±1.1, P<0.048) and for moderate to severe OSA (Epworth Sleepiness Scale 9.7±0.4 versus 7.1±0.9, P=0.043 and body mass index 36.4±0.8 versus 27.2±0.8 kg/m2, P<0.025). Conclusions— For a given severity of OSA, patients with stroke had less daytime sleepiness and lower body mass index than subjects without stroke. These factors may make the diagnosis of OSA elusive in the poststroke period and preclude many such patients from the potential benefits of OSA therapy.

Obstructive Sleep Apnea during REM Sleep and Hypertension. Results of the Wisconsin Sleep Cohort

RATIONALE Obstructive sleep apnea (OSA) is associated with hypertension. OBJECTIVES We aimed to quantify the independent association of OSA during REM sleep with prevalent and incident hypertension. METHODS We included adults enrolled in the longitudinal community-based Wisconsin Sleep Cohort Study with at least 30 minutes of REM sleep obtained from overnight in-laboratory polysomnography. Studies were repeated at 4-year intervals to quantify OSA. Repeated measures logistic regression models were fitted to explore the association between REM sleep OSA and prevalent hypertension in the entire cohort (n = 4,385 sleep studies on 1,451 individuals) and additionally in a subset with ambulatory blood pressure data (n = 1,085 sleep studies on 742 individuals). Conditional logistic regression models were fitted to longitudinally explore the association between REM OSA and development of hypertension. All models controlled for OSA events during non-REM sleep, either by statistical adjustment or by stratification. MEASUREMENTS AND MAIN RESULTS Fully adjusted models demonstrated significant dose-relationships between REM apnea-hypopnea index (AHI) and prevalent hypertension. The higher relative odds of prevalent hypertension were most evident with REM AHI greater than or equal to 15. In individuals with non-REM AHI less than or equal to 5, a twofold increase in REM AHI was associated with 24% higher odds of hypertension (odds ratio, 1.24; 95% confidence interval, 1.08-1.41). Longitudinal analysis revealed a significant association between REM AHI categories and the development of hypertension (P trend = 0.017). Non-REM AHI was not a significant predictor of hypertension in any of the models. CONCLUSIONS Our findings indicate that REM OSA is cross-sectionally and longitudinally associated with hypertension. This is clinically relevant because treatment of OSA is often limited to the first half of the sleep period leaving most of REM sleep untreated.

Periodic leg movements during sleep are associated with polymorphisms in BTBD9, TOX3/BC034767, MEIS1, MAP2K5/SKOR1, and PTPRD.

STUDY OBJECTIVES To examine association between periodic leg movements (PLM) and 13 single nucleotide polymorphisms (SNPs) in 6 loci known to increase risk of restless legs syndrome (RLS). SETTING Stanford Center for Sleep Sciences and Medicine and Clinical Research Unit of University of Wisconsin Institute for Clinical and Translational Research. PATIENTS Adult participants (n = 1,090, mean age = 59.7 years) from the Wisconsin Sleep Cohort (2,394 observations, 2000-2012). DESIGN AND INTERVENTIONS A previously validated automatic detector was used to measure PLMI. Thirteen SNPs within BTBD9, TOX3/BC034767, MEIS1 (2 unlinked loci), MAP2K5/SKOR1, and PTPRD were tested. Analyses were performed using a linear model and by PLM category using a 15 PLM/h cutoff. Statistical significance for loci was Bonferroni corrected for 6 loci (P < 8.3 × 10(-3)). RLS symptoms were categorized into four groups: likely, possible, no symptoms, and unknown based on a mailed survey response. MEASUREMENTS AND RESULTS Prevalence of PLMI ≥ 15 was 33%. Subjects with PLMs were older, more likely to be male, and had more frequent RLS symptoms, a shorter total sleep time, and higher wake after sleep onset. Strong associations were found at all loci except one. Highest associations for PLMI > 15/h were obtained using a multivariate model including age, sex, sleep disturbances, and the best SNPs for each loci, yielding the following odds ratios (OR) and P values: BTBD9 rs3923809(A) OR = 1.65, P = 1.5×10(-8); TOX3/BC034767 rs3104788(T) OR = 1.35, P = 9.0 × 10(-5); MEIS1 rs12469063(G) OR = 1.38, P = 2.0 × 10(-4); MAP2K5/SKOR1 rs6494696(G) OR = 1.24, P = 1.3×10(-2); and PTPRD(A) rs1975197 OR = 1.31, P = 6.3×10(-3). Linear regression models also revealed significant PLM effects for BTBD9, TOX3/BC034767, and MEIS1. Co-varying for RLS symptoms only modestly reduced the genetic associations. CONCLUSIONS Single nucleotide polymorphisms demonstrated to increase risk of RLS are strongly linked to increased PLM as well, although some loci may have more effects on one versus the other phenotype.

How Connectedness Contributes to Experimental Smoking Among Rural Youth: Developmental and Ecological Analyses

The influences of peer, sibling, and parents’ smoking on adolescents’ initiation of tobacco use have been explained as a function of peer pressure, genetics, and social learning processes, but rarely in combination or with assessments of the quality of these relationships. This study examined the additional contributions of connectedness to friends, siblings, parents, and teachers beyond the effects of friend, sibling, and parental smoking using logistic regression analyses with a cross-sectional middle and high school sample of 303 rural adolescents. Friends’ and siblings’ smoking, and connectedness to friends, were the strongest predictors of experimental smoking. Parental smoking and connectedness to parents and to teachers were significant predictors of experimental smoking when considered independently, but not after accounting for friend and sibling factors. Connectedness to parents and teachers decreased the odds of experimental smoking, while connectedness to friends increased the odds.Editors’ Strategic Implications: This strategy of assessing connectedness to–and smoking behaviors of—friends, siblings, teachers, and parents shows promise in predicting teens’ cigarette smoking choices. The finding that the negative effects of unconventional connectedness and smoking by friends and siblings outweigh positive effects of connectedness to adults awaits replication with different samples and measures.

A human period gene (HPER1) polymorphism is not associated with diurnal preference in normal adults.

Mammalian circadian rhythmicity has recently been shown to be regulated at the genetic level by transcription--translation feed-back loops. Key molecular components such as Clock, Bmal-1, Timeless and three Period proteins have been isolated in mammals. In this study, we hypothesized that polymorphisms at the level of one of these genes--HPER1--could be associated with differential morningness-eveningness tendencies. The sample comprised 463 middle-aged participants enrolled in the Wisconsin Sleep Cohort Study. Diurnal preferences were evaluated using the Horne-Ostberg questionnaire. An A to G synonymous substitution at position 2548 was identified in HPER1 c-DNA sequence by comparing available sequence data. This polymorphism was verified by sequencing and typed using established oligotyping techniques in all subjects, yielding allele frequencies of 0.85 and 0.15 for HPER1 2548G and HPER1 2548A, respectively. Morningness-eveningness scores were then compared between genotype groups. In contrast to data previously published using a Clock polymorphism, scores did not differ significantly across HPER1 groups. These results suggest that polymorphism at the level of HPER1 does not significantly modulate morningness-eveningness tendencies in the general population.