admission and discharge data, and health insurance data. However, workers’ compensation (WC)
systems are generally different from region to region, and health insurance information may be
incomplete or inaccurate, especially for those part-time workers without health insurance [187–190].
In addition, longitudinal studies are preferable for characterizing long-term respiratory health effect.
Although it is challenging to track cohorts with high mobility, such as migrant and seasonal
farmworkers, longitudinal data are especially critical for characterizing the association and establishing
a temporal relationship between occupational exposures and health outcome [187,191].
In summary, epidemiological studies require careful measurement of both exposures and outcomes
when assessing the relationships between occupational pesticide exposures and respiratory health.
In addition, proper evaluation of important biases, confounders, and effect modifiers, such as genetic
predisposition, social, and psychological factors, are important for avoiding spurious results in
association studies. It is also important to use longitudinal approaches when there were temporal
variations in pesticide exposures.
6. Conclusions