Introduction: There is growing evidence suggesting that lung capacity is associated with risk of cardiometabolic disease. However, most studies rely on spirometric measures of lung capacity and self-reported cardiometabolic disease. We aimed to investigate the association of total lung capacity (TLC) with cardiometabolic disease defined using ICD-10 codes.

Methods: Data from adult patients referred to Cambridge University Hospitals between 2016 and 2024 were used if spirometry, single breath gas transfer, and body plethysmography were performed in the same session. GLI reference equations were used to generate z-scores for lung function measures. ICD-10 codes for cardiovascular disease, hypertension, and diabetes were extracted from medical records. We used multi-level (mixed-effects) Cox regression analysis to investigate the association between lung function measurements and incident cardiometabolic disease.

Results: 5628 patients were included, 51% were female, with a median age of 62 (IQR 50-70) years. 60% reported a smoking history. Mean follow-up time was 5.7 (SD 2.3) years, during which time 5% received a cardiovascular disease code, 7% a hypertension code, and 3% a diabetes code. A 1-unit increment in TLC z-score was associated with a 12% lower risk of cardiovascular disease (HR: 0.88, 95%CI 0.80-0.97) later in life. The same was seen for FVC (HR: 0.88, 95%CI 0.77-0.99) but not FEV1/FVC or DLCO. A larger TLC was also associated with lower risk of myocardial infarction. We found no association of lung function measures with incident hypertension or diabetes.

Conclusion: Lung capacity is a determinant for cardiovascular disease and myocardial infarction, with larger lungs being protective. TLC and FVC should be considered by clinicians along with other factors, when evaluating a person’s risk of cardiovascular disease.