Brevetoxins and emergency department visits among children: A case-crossover study of Florida red tides.

Background: Algal blooms of Methods: We analyzed ED visits from coastal southwest Florida residents aged 0-18 years in the OneFlorida+ network (2012-2019) using a time-stratified case-crossover design with case and control days matched by week, day, month, and year. Two brevetoxin exposure indices were estimated for the prior 2 weeks (Lags Results: Overall associations were null, as were associations for the negative controls. Stratified models showed: (1) same-day increases in waterborne and aerosolized exposures were associated with ~50% higher odds of respiratory visits (216 cases); (2) increases in waterborne exposures 12-13 days prior were modestly associated with ear, nose, throat, dental, and mouth diseases (321 cases); and (3) increases in aerosolized exposures 6-9 days prior were associated with ~50% higher odds of eye diseases (53 cases). Conclusions: Brevetoxins may trigger ED visits for respiratory, eye, and ear-nose-throat complaints among children in coastal southwest Florida. As red tides in the Gulf increase, public health guidance tailored to children may be needed.