2009 Southern Regional Meeting Abstracts

Purpose of Study: Sleep loss is believed to adversely affect diverse immune functions (lymphopenia). As opposed to the well defined effects on immunity of acute, laboratory induced, sleep deprivation; the impact of chronic, interrupted, poor quality sleep—as seen in obstructive sleep apnea (OSA)—has not been thoroughly evaluated. We aim to explore the relationship between leukocyte/lymphocyte counts and Apnea Hypopnea Index (AHI) in patients diagnosed with OSA (stratified by severity).
Methods Used: We conducted an IRB approved retrospective review (October 2005 - July 2006) of 122 patients diagnosed with obstructive sleep apnea using a full-night diagnostic polysomnogram (PSNG). Data collected were demographics, co-morbidities, total neutrophil, & lymphocyte count, Body Mass Index (BMI), AHI and Epworth sleepiness scales (ESS). For the AHI variable, three strata were constructed: mild (5-14), moderate (15-29), and severe (> 30). We described data with frequency terms, continuous data by mean + standard deviation (+ SD), and categorical data by counts & percentages. Student t test or one-way ANOVA were used when appropriate to compare continuous variables; Chi-Squared test (χ2) for categorical variables. Data were later fitted in a linear regression model on which lymphocyte counts were the dependent variable, against age, BMI, AHI. All tests are two-sided and a p < 0.05 was considered as statistically significant. We used Statview Version 5.01 (SAS institute Inc. Cary, NC) for the statistical analysis.
Summary of Results: Our study showed a linear association among AHI (dependent) & BMI (predictive variable) p=0.0017 but did not show a significant association between lymphocyte count with: either BMI (p=0.33) or AHI (p=0.90). A negative association between Lymphocyte and age (p=0.02) was found that persisted even after multiple linear regression adjustment for BMI & AHI. An interaction product was also explored (age*AHI) but such carrier was not associated statistically with the lymphocyte count (p=0.87).
Conclusions: We found that chronic, interrupted, poor quality sleep—as seen in OSA -was not associated with lymphocyte counts and AHI severity did not influenced it either.