Ethnicity and spirometric indices: hostage to tunnel vision?

Abstract

The term vital capacity was coined by John Hutchinson, the inventor of spirometry, since the total volume of air exhaled from fully inflated lungs seemed to be inversely predictive of mortality. A century later, data from the Framingham Heart Study cohort reaffirmed that forced vital capacity (FVC) normalised to height is an independent marker of all-age cardiovascular risk, including after adjustment for traditional risk factors, such as age, obesity, blood pressure, smoking, heart rate, serum cholesterol, and blood glucose concentration. The predictive power of a low FVC is independent of clinical airway obstruction, such that in the Atherosclerosis Risk in Communities (ARIC) study, restrictively low lung function (characterised by low FVC) was associated with a 70% increase in mortality, including heart disease and diabetes. The reduced FVC of restrictively low lung function corresponds with a true reduction in lung volumes. Variations in FVC are associated with extrapulmonary disease, but the underlying mechanisms are unclear; possible shared mechanisms are summarised in the figure.