Document Type

Article

Department

Community Health Sciences; Diabetes/Endocrinology and Metabolism

Abstract

Background: The associations between the extent of forced expiratory volume in 1 s (FEV1) impairment and mortality, incident cardiovascular disease, and respiratory hospitalisations are unclear, and how these associations might vary across populations is unknown.
Methods: In this international, community-based cohort study, we prospectively enrolled adults aged 35-70 years who had no intention of moving residences for 4 years from rural and urban communities across 17 countries. A portable spirometer was used to assess FEV1. FEV1 values were standardised within countries for height, age, and sex, and expressed as a percentage of the country-specific predicted FEV1 value (FEV1%). FEV1% was categorised as no impairment (FEV1% ≥0 SD from country-specific mean), mild impairment (FEV1% -1 SD), moderate impairment (FEV1% 1%
Findings: Among 126 359 adults with acceptable spirometry data available, during a median 7·8 years (IQR 5·6-9·5) of follow-up, 5488 (4·3%) deaths, 5734 (4·5%) cardiovascular disease events, and 1948 (1·5%) respiratory hospitalisation events occurred. Relative to the no impairment group, mild to severe FEV1% impairments were associated with graded increases in mortality (HR 1·27 [95% CI 1·18-1·36] for mild, 1·74 [1·60-1·90] for moderate, and 2·54 [2·26-2·86] for severe impairment), cardiovascular disease (1·18 [1·10-1·26], 1·39 [1·28-1·51], 2·02 [1·75-2·32]), and respiratory hospitalisation (1·39 [1·24-1·56], 2·02 [1·75-2·32], 2·97 [2·45-3·60]), and this pattern persisted in subgroup analyses considering country income level and various baseline risk factors. Population-attributable risk for mortality (adjusted for age, sex, and country income) from mildly to moderately reduced FEV1% (24·7% [22·2-27·2]) was larger than that from severely reduced FEV1% (3·7% [2·1-5·2]) and from tobacco use (19·7% [17·2-22·3]), previous cardiovascular disease (5·5% [4·5-6·5]), and hypertension (17·1% [14·6-19·6]). Population-attributable risk for cardiovascular disease from mildly to moderately reduced FEV1 was 17·3% (14·8-19·7), second only to the contribution of hypertension (30·1% [27·6-32·5]).
Interpretation: FEV1 is an independent and generalisable predictor of mortality, cardiovascular disease, and respiratory hospitalisation, even across the clinically normal range (mild to moderate impairment).

Publication

Lancet Global Health

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