Age Trajectories of O2 Saturation and Levels of Serum Bicarbonate or End-Tidal CO2 Across the Life Course of Women and Men: Insights from EHR and PSG Data

TL;DR

This study examines how oxygen and CO2 levels change with age in men and women using health records and sleep data, revealing gender-specific patterns.

Contribution

The study provides novel age-specific trajectories of gas exchange parameters in women and men across the lifespan.

Findings

Women aged 15–45 had higher O2 saturation and lower CO2 levels than men.

Female–male differences in O2 and CO2 were greater pre-menopause than post-menopause.

Post-menopausal women had higher CO2 levels than men, unlike pre-menopausal women.

Abstract

To elucidate the changes in gas exchange across the life course, we estimated the age trajectories of O2 saturation, CO2 (as either end-tidal or serum bicarbonate), resting heart rate, and resting respiratory rate from age 2 yr onward in female and male patients separately. We utilized two sources’ data: electronic health records (EHR) representing ambulatory visits of approximately 53,000 individuals and sleep clinic polysomnogram (PSG) records representing an additional ~21,000. We used linear regression to estimate age-group-specific mean response levels for women and men. We compared estimated female–male differences between pre- and post-pubertal children and between pre- and post-menopausal periods among adults. Women between 15 and 45 years had higher O2 saturation and lower serum bicarbonate levels or end-tidal CO2 levels than men of similar ages. For O2 saturation and for both measures of CO2, the female–male difference was larger on average among adults at pre-menopausal ages than those at post-menopausal ages. Women had higher O2 saturation throughout their lives than men; however, the difference disappeared in the elderly. Women between menarche and menopause had significantly lower end-tidal CO2 and serum bicarbonate than men of similar ages. After menopause, however, women appeared to have higher mean levels of both end-tidal CO2 and serum bicarbonate than men.

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