Lung Function of Circumpolar Residents Undergoing Acculturation—a Ten Year Follow-up of Canadian Inuit

In 1980/81, Stead-Wells determinations of FVC, FEV^ 0 and MMEF were made on 341 Inuit aged 9-76 years, living in the settlement of Igloolik (69° 40’N). The same observers had used the same equipment to test 196 members of the same community (including 69 of the same adults) in 1970/71. Cross-sectional data for children participating in the two surveys were analysed by fitting exponential functions of the type FVC = a(H)b; similar height exponents (b) were demonstrated for the two surveys. Cross-sectional data for adults were analysed by multiple regressions of the type FVC = a(H) + b(Age) + c. In 1980/81, young adults had larger lung volumes, and the elderly smaller volumes than a decade previously, so that the cross-sectional aging coefficients (b) were increased; however, this effect was abolished if subjects with specific respiratory disease were excluded from the sample. Longitudinal data indicated that over the period 1970/71 to 1980/81, there was an accelerating loss of function in older cohorts. This picture was unchanged by excluding individuals with a history of specific respiratory disease. Even more rapid deterioration of lung function has been described in neighbouring Inuit communities. Although cigarette smoking has increased substantially among the Igloolik Inuit over the past decade, equally large functional losses were observed in three middle-aged, non-smoking men. Exposure to severe cold could hardly explain a curvilinearity of functional loss in both men and women. Other possibilities are inhalation of soot and non-specific respiratory pathogens when living in the closed atmosphere of an igloo. Irrespective of mechanisms, a curvilinearity of apparent aging could arise from survival of a cohort with poor lung function