This study investigated whether there is a difference in pulmonary function between healthy adult US-born Asian Indians and immigrant Asian Indians attributable to country of birth, environmental, and socioeconomic factors.
FEV1, FVC, and forced mid-expiratory flow between 25% and 75% of vital capacity (FEF25-75) were measured in India-born and US-born subjects residing in the Chicago metropolitan area. Hollingshead Index of Social Position was used to evaluate socioeconomic factors.
There were 262 India-born (61.8% male), and 200 US-born (50% male) subjects who were healthy lifelong nonsmokers; their age range was 16 to 36 years. US-born Asian Indian men and women were taller and had higher pulmonary function values for height and age compared with immigrant Asian Indian men and women. The differences were most pronounced in women: about 7% for FVC, 9% for FEV1, and 17% for FEF25-75. Immigrant and US-born subjects did not differ in socioeconomic position.
We conclude that US-born Asian Indian men and women have higher pulmonary function values for age and height compared with immigrant Asian Indian men and women. This probably reflects the effect of differing environmental conditions, which cause year-of-birth trends in lung volumes.