Homocysteine as a predictor of apnea–hypopnea index in obstructive sleep apnea: a longitudinal epidemiological study (EPISONO)

Obstructive sleep apnea (OSA) affects nearly 1 billion people globally, and has established links with cardiovascular and neurocognitive complications. Although it has some limitations, the apnea–hypopnea index (AHI) is commonly used to gauge OSA severity and therapeutic response. Homocysteine (Hcy) metabolism, when impaired, can elicit cellular senescence mechanisms that may be shared with OSA. Hence, our objective was to explore the role of Hcy concentrations both as a predictor of AHI values and as a potential risk factor for OSA.

Involving 1042 volunteers aged 20 to 80 years, the initial study (2007) included polysomnographic evaluations, questionnaires on sleep and general health, as well as biochemical analyses. After an 8-year interval, 715 participants from the initial study were invited for a follow-up assessment in 2015.

Our findings showed that Hcy was a predictor for an increased AHI, and AHI increased over time. Individuals with plasma Hcy concentrations ≥ 15 µmol/L experienced an average AHI increase of 7.43 events/hour ([beta coefficient] β = 7.43; 95%CI 2.73 to 12.13) over time, compared to those with plasma concentrations < 10 µmol/L. A similar trend was apparent in those with plasma Hcy concentrations between 10 ≥  and  < 15 µmol/L, who had an AHI increase with an average beta coefficient of 3.20 events/hour (95%CI 1.01 to 5.39) compared to those with plasma Hcy concentrations < 10 µmol/L.

In summary, our study suggests that increased plasma Hcy concentrations could be considered a risk factor for the development of OSA. These findings highlight that elevated plasma Hcy concentrations can predict the severity of OSA, underscoring their correlation with the AHI.