title: Etiology of ethnic differences in childhood spirometry.
abstract: OBJECTIVE
  Age- and height-adjusted spirometric lung function of South Asian children is lower than those of white children. It is unclear whether this is purely genetic, or partly explained by the environment. In this study, we assessed whether cultural factors, socioeconomic status, intrauterine growth, environmental exposures, or a family and personal history of wheeze contribute to explaining the ethnic differences in spirometric lung function.
  
  
  METHODS
  We studied children aged 9 to 14 years from a population-based cohort, including 1088 white children and 275 UK-born South Asians. Log-transformed spirometric data were analyzed using multiple linear regressions, adjusting for anthropometric factors. Five different additional models adjusted for (1) cultural factors, (2) indicators of socioeconomic status, (3) perinatal data reflecting intrauterine growth, (4) environmental exposures, and (5) personal and family history of wheeze.
  
  
  RESULTS
  Height- and gender-adjusted forced vital capacity (FVC) and forced expired volume in 1 second (FEV1) were lower in South Asian than white children (relative difference -11% and -9% respectively, P < .001), but PEF and FEF50 were similar (P ≥ .5). FEV1/FVC was higher in South Asians (1.8%, P < .001). These differences remained largely unchanged in all 5 alternative models.
  
  
  CONCLUSIONS
  Our study confirmed important differences in lung volumes between South Asian and white children. These were not attenuated after adjustment for cultural and socioeconomic factors and intrauterine growth, neither were they explained by differences in environmental exposures nor a personal or family history of wheeze. This suggests that differences in lung function may be mainly genetic in origin. The implication is that ethnicity-specific predicted values remain important specifically for South Asian children.
authors.affiliation: Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland.
authors.forename: Marie-Pierre Françoise
authors.initials: MP
authors.lastname: Strippoli
authors.forename: Claudia Elisabeth
authors.initials: CE
authors.lastname: Kuehni
authors.forename: Cristian Mihai
authors.initials: CM
authors.lastname: Dogaru
authors.forename: Ben Daniel
authors.initials: BD
authors.lastname: Spycher
authors.forename: Teresa
authors.initials: T
authors.lastname: McNally
authors.forename: Michael
authors.initials: M
authors.lastname: Silverman
authors.forename: Caroline Sarah
authors.initials: CS
authors.lastname: Beardsmore
mesh_terms: D000293:Adolescent; D000886:Anthropometry; D044466:Asian People; D001827:Body Height; D002648:Child; D005006:Ethnicity / Q000706:statistics & numerical data*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D016014:Linear Models; D008168:Lung / Q000503:physiopathology*; D008297:Male; D012959:Socioeconomic Factors; D013147:Spirometry / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires; D006113:United Kingdom
keywords: South Asian; ethnicity; lung function measurements; lung mechanics; migration