Does seasonal employment in grain elevators increase nonspecific airways responsiveness?

Grain handling and increased airways responsiveness (AR) have been independently associated with an accelerated decline in forced expiratory volume in 1 sec. We performed methacholine inhalation bronchial challenge tests in 45 river port grain handlers during layoff and again during employment to determine whether short-term exposure increased AR. To assess bias, due to seasonal/temporal influences, AR was also measured in 56 nonexposed men of similar age and socioeconomic status. AR, slightly higher among laid-off grain handlers than the comparison group, fell more among grain handlers during employment than among the comparison group during the same time period. Our results do not support the hypothesis that seasonal exposure to grain dust increases AR.