BACKGROUND: The contribution of obesity to hypoxemia has not been reported in a communitybased study. Our hypothesis was that increasing obesity would be independently associated with lower ApO2 in an ambulatory elderly population. METHODS: The Cardiovascular Health Study ascertained resting ApO2 in 2,252 subjects over age 64. We used multiple linear regression to estimate the association of body mass index (BMI) with ApO2 and to adjust for potentially confounding factors. Covariates including age, sex, race, smoking, airway obstruction (based on spirometry), self reported diagnosis of emphysema, asthma, heart failure, and left ventricular function (by echocardiography) were evaluated. RESULTS: Among 2,252 subjects the mean and median ApO2 were 97.6% and 98.0% respectively; 5% of subjects had ApO2 values below 95%. BMI was negatively correlated with ApO2 (Spearman R = -0.27, P <.001). The mean difference in ApO2 between the lowest and highest BMI categories (< 25 kg/m2 and > 35 kg/m2) was 1.33% (95% CI 0.89 -1.78%). In multivariable linear regression analysis, ApO2 was significantly inversely associated with BMI (1.4% per 10 units of BMI, 95% CI 1.2-1.6, for whites/others, and 0.87% per 10 units of BMI, 95% CI 0.47-1.27, for African Americans). CONCLUSIONS: We found a narrow distribution of ApO2 values in a community-based sample of ambulatory elderly. Obesity was a strong independent contributor to a low ApO2, with effects comparable to or greater than other factors clinically associated with lower ApO2.
- Body mass index
- Pulmonary function test
- Pulse oximetry
- Waist circumference
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
- Critical Care and Intensive Care Medicine