Are ethnic differences in lung function explained by chest size?
BACKGROUND
Ethnic differences in lung function (LF) are recognised in adults and children. Most prediction equations for LF are derived from whites, so non-whites are at risk of erroneous assessment. It was hypothesised that differences in chest dimensions would explain differences in LF between Asian (Indian) and white schoolchildren.


OBJECTIVE
To quantify the impact of chest dimensions on LF, which would inform our understanding of ethnic differences that have implications for health care.


METHODS
Children aged 6-11 were studied in school. A questionnaire provided information on ethnicity and respiratory health. Spirometry was used to record FVC, FEV1, FEF25-75, and PEF. Weight, height, sitting height, and chest dimensions (chest height, circumference, antero-posterior and transverse diameters) were measured.


RESULTS
Data were obtained from 294 healthy children. Standing height was the most important predictor of LF. Ethnicity was an independent predictor for all LF measures except PEF, where the effect was marginal. FVC in whites was 13.4% bigger than in Asians of the same height, and the FEV1 was 10.6% greater in whites. The influence of chest dimensions on lung function was trivial. Body mass index was smaller in Asians but did not explain differences in LF.


CONCLUSIONS
Differences in chest dimensions did not explain the substantial effect of ethnicity on LF. Mechanisms whereby ethnicity exerts its influence may include differences in inspiratory muscle strength or lung compliance but remain speculative. Nevertheless it remains imperative that ethnic differences are recognised when interpreting LF tests.
Whittaker
A L
AL
Department of Child Health, Leicester Warwick Medical School, UK.
Sutton
A J
AJ
Beardsmore
C S
CS
D000886:Anthropometry / Q000379:methods; D001827:Body Height / Q000502:physiology; D002648:Child; D005006:Ethnicity; D005260:Female; D005540:Forced Expiratory Flow Rates; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D007194:India / Q000208:ethnology; D016014:Linear Models; D008168:Lung / Q000502:physiology*; D008297:Male; D010366:Peak Expiratory Flow Rate / Q000502:physiology; D015656:Respiratory Mechanics; D013147:Spirometry; D013909:Thorax / Q000033:anatomy & histology*; D014797:Vital Capacity / Q000502:physiology; D044465:White People