Ferritin is a potential marker of cardiometabolic risk in adolescents and young adults with sleep-disordered breathing.

Objective: To explore markers that reflect sleep-disordered breathing (SDB) severity and investigate their associations with cardiometabolic risk factors in adolescents and young adults. Methods: Participants were recruited from our SDB epidemiological cohort. They underwent overnight polysomnography and ambulatory blood pressure (BP) monitoring. Complete blood count, ferritin, high-sensitivity C-reactive protein (hs-CRP), fasting blood glucose, and lipid profile were measured. Multiple linear regression was used to examine the association between red cell indices (RCIs), ferritin, and obstructive apnea-hypopnea index (OAHI). Subgroup analyses on participants with SDB were performed for the association of RCIs and ferritin with lipid profile, hs-CRP, and BP. Results: There were 88 participants with SDB and 155 healthy controls aged 16-25 years. Hemoglobin (Hb; p < .001), hematocrit (HCT; p < .001), and ferritin (p < .001) were elevated with increasing SDB severity and were independently associated with OAHI (ß=1.06, p < .001; ß=40.2, p < .001; ß=4.89 × 10-3, p = .024, respectively). In participants with SDB, after adjusting for age, sex, and BMI, significant associations were found between ferritin with low-density lipoprotein (LDL; ß=0.936 × 10-3, p = .008) and triglyceride (TG; ß =1.08 × 10-3, p < .001), as well as between Hb (ß=1.40, p = .007), HCT (ß=51.5, p = .010) and mean arterial pressure (MAP). Ferritin (ß=0.091, p = .002), Hb (ß=0.975, p = .005), and HCT (ß=38.8, p = .004) were associated with hs-CRP independent of age, sex, BMI, plasma LDL, and MAP. OAHI was not associated with LDL and TG in the multivariable models. Conclusions: Serum ferritin, but not OAHI, was associated with LDL and TG in participants with SDB, suggesting it is a potential marker of cardiometabolic risk in patients with SDB.

The cross-sectional and longitudinal relationship of diabetic retinopathy to cognitive impairment: a systematic review and meta-analysis.

OBJECTIVES: To establish a potential relationship between diabetic retinopathy (DR) and different stages of cognitive impairment METHODS: Literature searches were conducted on PubMed and EMBASE, with keywords "diabetic retinopathy" and "cognitive impairment". Inclusion criteria were original human studies, and English language. Quality of studies was assessed by the Newcastle-Ottawa Quality Assessment (NOSGEN). The register number of this study on the International Prospective Register of Systematic Reviews (PROSPERO) is CRD42021236747. The main outcome measures were odds ratios (OR) and risk ratios (RR) for cross-sectional and longitudinal studies, respectively. Meta-regression was performed to evaluate the effects of potential moderator variables, including, age, onset age of diabetes mellitus (DM), duration of DM, and HbA1c. RESULTS: Twenty-five studies (17 cross-sectional and 8 longitudinal studies) with a total of 1,963,914 subjects, were included. Among the cross-sectional studies, the pooled ORs of any cognitive impairment, early stage of cognitive impairment and dementia in subjects with DR (95% confidence interval) were 1.48 (1.08-2.02), 1.59 (1.01-2.51), and 1.13 (0.86-1.50), respectively. Among the longitudinal studies, the pooled RRs of any cognitive impairment, early stage of cognitive impairment, and dementia in subjects with DR (95% confidence interval) were 1.35 (1.12-1.65), 1.50 (1.06-2.12), and 1.31 (1.03-1.66), respectively. Meta-regression showed age, onset age of DM, duration of DM, and glycated hemoglobin (HbA1c) were not statistically associated with the outcomes. CONCLUSIONS: The presence of DR in DM patients indicates both higher odds of prevalent cognitive impairment and escalated risks of developing cognitive impairment in the future.

Level of urinary catecholamine in children with Sleep Disordered Breathing: A systematic review and meta-analysis.

OBJECTIVE: To compare the levels of different urinary catecholamines amongst paediatric patients with and without sleep-disordered breathing (SDB). METHODS: Literature searches were conducted on PubMed and EMBASE until 25/06/2022. Inclusion criteria were original human studies, English language, paediatric subjects diagnosed with SDB/obstructive sleep apnoea (OSA). The quality of studies was assessed by the Newcastle-Ottawa Quality Assessment (NOSGEN). The registered number of this study on the International Prospective Register of Systematic Reviews (PROSPERO) is CRD42022332939. The main outcome measured was standardised mean difference (SMD) of urinary catecholamine between subjects with and without SDB, between those with and without OSA, and also between subjects with mild OSA and those with moderate/ severe OSA. Sensitivity analyses were performed to avoid bias. RESULTS: 9 studies (8 cross-sectional and 1 cohort study) with a total of 838 subjects, were included in the quantitative analysis. Urine level of noradrenaline was higher in patients with SDB, which included primary snoring (PS), when compared to controls: SMD = 0.86 (95%CI=0.32-1.41; I2=85%, P=0.002). The levels of urinary noradrenaline and adrenaline were higher in children with OSA when compared to controls: SMD = 1.45 (95%CI=0.91-2.00; I2=75%, P < 0.001); SMD = 1.84 (0.00-3.67; I2=97%, P=0.05). Urine level of noradrenaline was higher in subjects with moderate/severe OSA compared to the mild OSA: SMD = 0.55 (95%CI=0.10-1.00; I2=0%, P=0.02). Urinary dopamine was not associated with SDB regardless of severity. CONCLUSIONS: Urinary noradrenaline was higher in all patients with SDB. Subjects with OSA, a more severe form of SDB, had higher urine levels of noradrenaline and adrenaline. Hence, noradrenaline and adrenaline may be markers of sympathetic overtone in patients with SDB and could potentially act as surrogate markers for SDB complications. Further studies are needed to assess this association.