Transferrin saturation is independently associated with the severity of obstructive sleep apnea syndrome and hypoxia among obese subjects

• Published in: Clinical nutrition (Edinburgh, Scotland) Scotland), 2021-02, Vol.40 (2), p.608-614
• Main Authors: Le Tallec-Estève, Noémie, Rousseau, Chloé, Desrues, Benoit, Loréal, Olivier, Thibault, Ronan
• Format: Article
• Language: English
• Subjects: Endocrinology and metabolism; Human health and pathology; Iron; Life Sciences; Metabolic syndrome; Obesity; Obesity surgery; Tissues and Organs
• ISSN: 0261-5614; 1532-1983
• DOI: 10.1016/j.clnu.2020.06.007

Obstructive sleep apnea syndrome (OSAS) is a frequent complication of obesity. Intermittent chronic hypoxia which frequently results from OSAS could modulate the systemic control of iron metabolism and alter serum iron parameters, especially among obese patients. Aims: to evaluate whether serum parameters of iron bioavailability and storage (primary), as well as age, waist circumference, arterial hypertension and tobacco use (secondary) are associated with OSAS severity and/or hypoxia. design: a single-center retrospective study with prospective data collection; inclusion criteria: consecutive patients referred for initial assessment for obesity underwent nocturnal respiratory polygraphy and iron status serum assessment within a 3-month period. The adjusted analyzes were performed using ANOVA and reported as adjusted means and 95% confidence interval (95% CI). 13 men and 56 women were included. OSAS prevalence: 72% (n = 50). Ferritin (mean ± SD, 260 ± 276 vs. 111 ± 89 μg/l, p = 0.01) and transferrin saturation (31 ± 10 vs. 24 ± 9%, p = 0.002) were significantly higher in case of moderate/severe OSAS than in absent/mild OSAS, independently from gender and tobacco use. Serum iron (19.4 μg/l [CI95%, 16.5–22.3] vs. 16.2 μg/l ([14.1–18.2], p = 0.056) and transferrin saturation (31.5% [26.3–36.7]) vs. 25.3% [21.6–29.1], p = 0.043) were higher when time under oxygen saturation 15%. Age (mean ± SD, 51 ± 11 vs. 41 ± 12 yr, p = 0.001), waist circumference (136 ± 18 vs. 123 ± 12 cm, p = 0.003), arterial hypertension (59% (n = 13/22) vs. 23% (n = 11/47), p = 0.004) and tobacco use (64% (n = 14/22) vs. 32% (n = 15/47), p = 0.01) were significantly greater in moderate/severe OSAS than in absent/mild OSAS. Transferrin saturation was associated with OSAS severity and time under hypoxia. This suggests a relationship between OSAS-induced hypoxia and iron metabolism among obese patients.