Spirometric prediction equations for male Italians 7-18 years of age

Relationship between body composition and pulmonary function in the general population-a cross-sectional study in Ningxia

Studies considering the relationship between non-obesity-related body composition and lung function are few; therefore, this study aimed to explore these correlations and effects. This cross-sectional study conducted in rural Qingtongxia City and Pingluo County, Ningxia, China, included 776 participants aged 30-75 years. Body composition and lung function were measured using direct segmental multifrequency bioelectrical impedance analysis and a digital spirometer, respectively. Their correlation was assessed using partial correlation analysis, controlling for age and smoking status, and the body composition effect on lung function was analyzed using binomial logistic regression analysis. The body components total body water content, protein content, mineral content, muscle mass, fat-free mass (FFM), skeletal muscle mass, basal metabolic volume, and chest circumference (CC) positively correlated with pulmonary function (forced vital capacity and forced expiratory volume in one second) in both sexes. Neck circumference and hip circumference positively correlated with pulmonary function in women. Additionally, lung function declines more slowly in women (odds ratio [OR] = 0.66, 95% confidence interval [CI] = 0.44-0.98, p =  0.04); CC (OR = 0.92, 95% CI = 0.86-0.98, p = 0.01) increased as a protective factor for decreased lung function. Increased waist circumference (OR = 1.04, 95% CI = 1.00-1.09, p = 0.04) was a risk factor for reduced lung function. FFM contains body composition indicators positively correlating with lung function, excluding fat-related body composition. Abdominal obesity increases the risk of decreased lung function.

Ratio of waist circumference to chest circumference is inversely associated with lung function in Chinese children and adolescents

BACKGROUND AND OBJECTIVE

In White children, waist circumference (WC) is positively correlated with forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV(1)). Because fat distribution differs among different races, the relationship between WC and lung function in Asian children may differ from that in White children. The present study aimed to examine the effect of WC on ventilatory function in Chinese children.

METHODS

A cross-sectional study was performed on 1572 healthy subjects aged 9-18 years. Height, weight, chest circumference (CC), WC and lung function (FVC, FEV(1), peak expiratory flow (PEF) and maximal mid-expiratory flow (MMEF)) were measured. To avoid the problem of colinearity, a model that combined CC and WC as the waist-to-chest ratio (WCR) was used. The relative contributions of WCR and body mass index (BMI) to spirometric parameters were determined by linear regression analysis.

RESULTS

WCR was inversely associated with all spirometric parameters. On average, each 0.01 increase in WCR was associated with decreases of 8.14 mL for FVC, 9.36 mL for FEV(1), 6.54% for FEV(1)/FVC, 19.81 mL/s for PEF and 17.25 mL/s for MMEF. BMI was positively associated with all spirometric parameters except FEV(1)/FVC. These results suggest that WC was inversely associated with lung function parameters.

CONCLUSIONS

Inverse associations were identified between WCR, as well as WC, and lung function in a population of Chinese children. The underlying mechanisms need to be further explored.

Spirometric reference values for children and adolescents from Kazakhstan

BACKGROUND

Spirometric parameters are influenced by several factors and many reference data are available in the literature. However, no spirometric data are available for children and adolescents from Central Asia.

AIM

The study aimed to calculate spirometric reference curves on the basis of anthropometry, ethnicity (Kazakh vs. Russian) and living environment (urban vs. rural).

SUBJECTS AND METHODS

Spirometry (FEV1, FVC and FEF25-75%) was performed and anthropometric measurements taken for 1926 male and 1967 female Kazakh children aged 7-18 years.

RESULTS

Height explained almost all the variance of forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) for both sexes, while age and inspiratory circumference contributed slightly to the prediction. Moreover, FVC and FEV1 were greater in Russians than in Kazakhs and ethnicity did enter the prediction model for these parameters. The living environment had a marginal effect on spirometry. In fact, forced expiratory flow 25-75% (FEF25-75%) was slightly higher in urban than in rural females, FVC was slightly higher in rural than in urban males, while FEV1 was not affected. Finally, among several spirometric equations available in the literature, those performing better in our children were obtained in developed countries.

CONCLUSION

Anthropometry was the most important predictor of spirometry. Age and ethnicity were also predictors, while the contribution of the living environment was more limited.