Occurrence of farmer's lung disease is relevant to meteorological conditions: A 20-year follow-up field survey analysis

Background A field survey on farmer's lung disease (FLD) in a dairy farming community in the northernmost district of Japan has been in progress since 1978. Methods The correlation between the number of FLD occurrences year by year and dairy farming conditions and meteorological data were compared. Results Thirty‐four FLD cases had occurred in a 20 years period. Average number of days below freezing during the harvest season the year prior to FLD occurrence were significantly smaller than other years (2.1 ± 0.7 [SE] days, 4.6 ± 0.7 days, P