Spirometric pattern and cardiovascular risk: a prospective study of 0.3 million Chinese never-smokers.

BACKGROUND

Existing studies have not provided robust evidence about the CVD risk of non-smoking patients with restrictive spirometric pattern (RSP) or airflow obstruction (AFO), and how the risk is modified by body shape. We aimed to bridge the gap.

METHODS

We used never-smokers' data from the China Kadoorie Biobank (CKB) and performed Cox models by sex (278,953 females and 50,845 males). Spirometry was used to assess the baseline spirometric pattern. CVD outcomes were captured through multiple sources.

FINDINGS

Females' results were presented primarily, though males' results were similar. During a median 12-year (maximum 14.5 years) follow-up, both RSP and AFO patients had increased risks of acute myocardial infarction (AMI), other ischaemic heart disease (other IHD), heart failure, pulmonary heart disease, arrhythmia, and intracerebral haemorrhage (ICH). RSP was also associated with ischaemic stroke (IS). The HRs (95% CIs) for AFO in females ranged from 1.29 (1.15-1.45) for ICH to 8.84 (7.79-10.03) for pulmonary heart disease, while those for RSP ranged from 1.11 (1.08-1.15) for IS to 3.17 (2.80-3.59) for pulmonary heart disease. These risks increased with the severity of AFO and reduced FVC. RSP/AFO was more strongly associated with other IHD, heart failure, and pulmonary heart disease in underweight females than in normal and obese counterparts, respectively.

INTERPRETATION

With the confounding of smoking fully controlled, both RSP and AFO were associated with higher risks of various CVD outcomes, which further increased with the severity of AFO and reduced FVC. These associations were even stronger in underweight individuals.

FUNDING

National Natural Science Foundation of China, National Key Research and Development Program of China, Ministry of Science and Technology of the People's Republic of China, Kadoorie Charitable Foundation, UK Wellcome Trust, UK Medical Research Council, Cancer Research UK, and British Heart Foundation.