Objective Derive continuous prediction equations and their lower limits of normal for spirometric indices, which are applicable globally. Material Over 160,000 data points from 72 centres in 33 countries were shared with the European Respiratory Society Global Lung Function Initiative. Eliminating data that could not be used (mostly missing ethnic group, some outliers) left 97,759 records of healthy nonsmokers (55.3% females) aged 2.5–95 years. Methods Lung function data were collated, and prediction equations derived using the LMS (λ, µ, σ) method, which allows simultaneous modelling of the mean (mu), the coefficient of variation (sigma) and skewness (lambda) of a distribution family. Results After discarding 23,572 records, mostly because they could not be combined with other ethnic or geographic groups, reference equations were derived for healthy individuals from 3–95 years for Caucasians (N=57,395), African Americans (N=3,545), and North (N=4,992) and South East Asians (N=8,255). FEV1 and FVC between ethnic groups differed proportionally from that in Caucasians, such that FEV1/FVC remained virtually independent of ethnic group. For individuals not represented by these four groups, or of mixed ethnic origins, a composite equation taken as the average of the above equations is provided to facilitate interpretation until a more appropriate solution is developed. Conclusion Spirometric prediction equations for the 3–95 age range are now available that include appropriate age-dependent lower limits of normal. They can be applied globally to different ethnic groups. Additional data from the Indian subcontinent, Arab, Polynesian, Latin American countries, and Africa will further improve these equations in the future.
A substantial proportion of patients with cryptococcosis are apparently immunocompetent. C. neoformans var. grubii and C. gattii are the common causes. Immunocompetent patients tend to present with localized, indolent neurological disease, with more intense inflammatory responses but better clinical outcomes.
In children, the ratio of forced expiratory volume in 1 s (FEV1) to forced vital capacity (FVC) is reportedly constant or falls linearly with age, whereas the ratio of residual volume (RV) to total lung capacity (TLC) remains constant. This seems counter-intuitive given the changes in airway properties, body proportions, thoracic shape and respiratory muscle function that occur during growth. The age dependence of lung volumes, FEV1/FVC and RV/TLC were studied in children worldwide.Spirometric data were available for 22,412 healthy youths (51.4% male) aged 4-20 yrs from 15 centres, and RV and TLC data for 2,253 youths (56.7% male) from four centres; three sets included sitting height (SH). Data were fitted as a function of age, height and SH.In childhood, FVC outgrows TLC and FEV1, leading to falls in FEV1/FVC and RV/TLC; these trends are reversed in adolescence. Taking into account SH materially reduces differences in pulmonary function within and between ethnic groups. The highest FEV1/FVC ratios occur in those shortest for their age.When interpreting lung function test results, the changing pattern in FEV1/FVC and RV/TLC should be considered. Prediction equations for children and adolescents should take into account sex, height, age, ethnic group, and, ideally, also SH.
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