Incident thyroid disease in female spouses of private pesticide applicators.

•We studied incident thyroid diseases and farm exposures in female spouses of farmers.•Several fungicides and insecticides were associated with higher hypothyroidism risk.•Conversely, long-term farm residence was associated with lower hypothyroidism risk.•Maneb/mancozeb and metolachlor were associated with higher hyperthyroidism risk.•This is the first large prospective study of farm exposures and incident thyroid diseases in women.