Spirometric prediction equations and the relationship between metabolic syndrome and spirometric parameters from an island in Fujian, China

Background: We investigated risk factors for decreased lung function among Chinese island residents (≥30 years) to determine the relationship between metabolic syndrome (MS) and decreased lung function. Methods: From October 17, 2011 to November 1, 2011, 2607 residents aged ≥30 years who lived on the Huangqi Peninsula of Fujian were enlisted by random cluster sampling. They completed a questionnaire designed according to the Burden of Obstructive Lung Disease (BOLD) questionnaire, and underwent physical examination, blood test, and lung function evaluation. We constructed spirometric prediction equations for forced vital capacity (FVC) and forced expiratory volume in one second (FEV1), determined the lower limits of normal for FVC, FEV1 and FEV1/FVC, and examined the relationship between lung function and MS. Results: Prediction equations for normal island residents were as follows: FVC (L) = −0.023 × age (years) + 0.042 × height (cm) + 0.641 × weight (kg) – 3.607 (males); FVC (L) = −0.017 × age (years) + 0.030 × height (cm) + 0.009 × weight (kg) – 1.741 (females); FEV1 (L) = −0.023 × age (years) + 0.040 × height (cm) + 0.010 × weight (kg) – 2.999 (males); FEV1 (L) = −0.017 × age (years) + 0.026 × height (cm) + 0.007 × weight (kg) −1.135 (females). The odds ratio for MS for increased risk of decreased FVC was 4.623 (95%CI =3.626–5.894, P<0.001), and for increased risk of decreased FEV1 was 3.043 (95%CI =2.447–3.785, P<0.001). Conclusions: MS is a risk factor for decreased lung function in island residents ≥30 years old.