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

Noémie Le Tallec-Estève (1) , Chloé Rousseau (1) , Benoît Desrues (2) , Olivier Loréal (3) , Ronan Thibault (3)

1 Centre Hospitalier Universitaire de Rennes [CHU Rennes] = Rennes University Hospital [Ponchaillou]
2 COSS - Chemistry, Oncogenesis, Stress and Signaling
3 NuMeCan - Nutrition, Métabolismes et Cancer

Introduction & aims - 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. Methods - 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).Results - 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 <90% was >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.Conclusions - 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.

Mots clés: Iron; Metabolic syndrome; Obesity; Obesity surgery

Domaines: Endocrinologie et métabolisme; Physiologie [q-bio.TO]

Noémie Le Tallec-Estève, Chloé Rousseau, Benoît Desrues, Olivier Loréal, Ronan Thibault. Transferrin saturation is independently associated with the severity of obstructive sleep apnea syndrome and hypoxia among obese subjects. Clinical Nutrition, 2021, 40 (2), pp.608-614. ⟨10.1016/j.clnu.2020.06.007⟩. ⟨hal-02887887⟩