Association Between Obstructive Sleep Apnea And Metabolic Disturbance In Patients With Different Demographic Features Or Lipoprotein(a) Levels

PART ONE Association between Obstructive Sleep Apnea and Metabolic Syndrome in Patients with Different Demographic FeaturesBackground:Previous studies implied that the association between obstructive sleep apnea(OSA)and metabolic syndrome may vary in patients with different demographic features.To explore these variations and their manifestation would deepen the understanding with regard to the relationship between OSA and metabolic disturbance.Purpose:To explore the association between OSA and metabolic syndrome in patients with different sex,age and body mass index(BMI).Method:A cross-sectional study was performed in 7834 candidates who were referred to the sleep apnea center of Shanghai Jiao Tong University Affiliated Sixth People's Hospital during July 2007 to December 2018.Demographic variables,anthropometric measurements,biochemical indicators,and laboratory-based polysomnographic indexes were collected for each.Statistical analysis was performed in 6367 adult participants who met the inclusion criteria.The severity of OSA(none,mild,moderate,severe)and the presence of metabolic syndrome(exist,not-exist)were defined according to the most recent guidelines.Firstly,participants were classified into eight subgroups according to sex and age(<40,40–49,50-59,?60 years old).Subgroup-specific adjusted odds ratio(OR)for metabolic syndrome as a function of OSA severity was calculated and compared with logistic regression,with the aim to identify the variation of ORs across age subgroups and the corresponding cut-off value of age.Secondly,participants were classified into six subgroups according to sex and BMI(<24,24–27.9,?28 kg/m~2),with the aim to identify the variation of ORs across BMI subgroups and the corresponding cut-off value of BMI.Finally,according to the cut-off value of age and BMI,along with sex,participants were reclassified into eight subgroups and ORs for different subgroups were calculated and compared with the same statistical method.Result:A total of 5073 males were enrolled,with a median age of 40 years and a median BMI of 26.5 kg/m~2;Among which,4398(86.7%)met the criterion of OSA and 2506(49.4%)met the criterion of metabolic syndrome.A total of 1294 females were enrolled,with a median age of 49 years and a median BMI of 24.8 kg/m~2;838(64.8%)met the criterion of OSA and 379(29.3%)met the criterion of metabolic syndrome.Classification according to sex and age revealed that males aged<60 years and females aged<50years had increased odds for the presence of metabolic syndrome as OSA severity increases.Classification according to sex and BMI revealed that nonobese(BMI<28 kg/m~2)males and nonobese females had increased odds for the presence of metabolic syndrome as OSA severity increases.Classification according to sex,age and BMI revealed that nonobese males aged<60 years and nonobese females aged<50 years had increased odds for the presence of metabolic syndrome as OSA severity increases(adjusted OR:1.88[1.57,2.25]and 3.74[1.87,7.55],respectively;both p<0.001).Conclusion:OSA severity is independently associated with an increased odd for the presence of metabolic syndrome in nonobese patients with younger age.Besides,the cut-off value of age differs by sex.PART TWO Association between Obstructive Sleep Apnea and Insulin Resistance in Patients with Different Serum Lipoprotein(a)LevelsBackground: Previous studies showed that specific comorbidity may have a synergistic effect with OSA on metabolic disturbance.To reveal such synergistic effect would deepen the understanding with regard to the relationship between OSA and metabolic disturbance.Abnormal level of serum lipoprotein(a)[Lp(a)] is a common comorbidity for OSA patients.Decreased Lp(a)level has been recently recognized as a risk factor for insulin resistance,however,whether it has a synergistic effect with OSA is still unknown.Purpose: To explore whether there is a synergistic effect between OSA and decreased Lp(a)level with regard to insulin resistance.Method: A cross-sectional study was performed in 7834 candidates who were referred to the sleep apnea center of Shanghai Jiao Tong University Affiliated Sixth People's Hospital during July 2007 to December 2018.Demographic variables,anthropometric measurements,biochemical indicators,and laboratory-based polysomnographic indexes were collected for each.Statistical analysis was performed in 5653 adult participants who met the inclusion criteria.The severity of OSA(none,mild,moderate,severe)was assessed by apnea-hypopnea index(AHI),according to the most recent guideline.The degree of insulin resistance was assessed by the homeostasis model assessment of insulin resistance(HOMA-IR),and insulin resistance state was defined as HOMA-IR > 3.Multivariable linear regression with an interaction term was used to investigate the potential synergistic effect between AHI and Lp(a)levels on HOMA-IR.Participants were then stratified into four subgroups according to the level of Lp(a)[quartile 1 to 4].Subgroup-specific adjusted OR for insulin resistance state as a function of OSA severity was calculated and compared with logistic regression,with the aim to further testify potential synergistic effect.Result: Participants of this study were with a median age of 40 years,a median BMI of 26.1 kg/m2,and a median AHI of 29.8 events/hour,and a median Lp(a)level of 7.5mg/d L;Among which,4651(81.8%)met the criterion of OSA and 2168(38.1%)met the criterion of insulin resistance state.Multivariable linear regression showed that AHI positively correlated,while Lp(a)level inversely correlated,with HOMA-IR.In addition,linear interaction analysis showed that,as Lp(a)level decreased,the association between AHI and HOMA-IR was much steeper and more significant,suggesting a synergistic effect(p-interaction = 0.018).Furthermore,interaction analysis on a multiplicative scale also demonstrated a significant synergistic effect.Stronger association between OSA severity and insulin resistance state could be observed for participants within lower Lp(a)quartiles(adjusted OR for quartile 4 to 1: 1.42 [1.04,1.96],1.42 [1.05,1.92],2.23 [1.66,3.10] and 2.16[1.59,2.95],respectively;p-interaction=0.021).Conclusion: There is a synergistic effect between OSA and decreased Lp(a)level with regard to insulin resistance.