Association of Childhood Respiratory Status with Adult Occupational Exposures in a Birth Cohort.

Rationale: People with better early-life respiratory health may be more likely to work in occupations with high workplace exposures in adult life compared with people with poor respiratory health. This may manifest as a healthy worker effect bias, potentially confounding the analysis of environmental exposure studies. Objectives: To evaluate associations between lung function in adolescence and occupational exposures at initial adult employment. Methods: The TCRS (Tucson Children's Respiratory Study) is a long-term prospective study of respiratory health beginning at birth. Associations between respiratory function at age 11 years and occupational exposures at first job at age 26 years were evaluated with logistic regression. We calculated percentage predicted values for forced expiratory volume in one second (FEV 1 ), forced vital capacity (FVC), FEV 1 :FVC ratio, and forced expiratory flow from 25% to 75% of vital capacity at age 11. At the 26-year visit, participants self-reported occupational exposures to dust, smoke, and fumes/gas at first job in a standardized interview. Results: Forced expiratory flow from 25% to 75% of vital capacity and FEV 1 :FVC ratio at age 11 were positively associated with dust workplace exposures at the first job. Each 10% increase in percentage predicted prebronchodilator FEV 1 :FVC ratio was associated with 30% higher odds of workplace dust exposure (odds ratio for a 1% increase, 1.03 [95% confidence interval, 1.00-1.06; P  = 0.045]). Similar associations were observed for FEV 1 and FVC with workplace smoke exposures. We also observed modification by time at job: associations were stronger for those who remained in their jobs longer than 12 months. In addition, those with better function at age 11 were more likely to stay in their jobs longer than 12 months if their first jobs involved exposure to dust. Conclusions: Childhood lung function affects initial career choice. This study supports the premise of the healthy worker effect.