title: A Prospective Study of Marine Phytoplankton and Reported Illness Among Recreational Beachgoers in Puerto Rico, 2009.
abstract: BACKGROUND
  Blooms of marine phytoplankton may adversely affect human health. The potential public health impact of low-level exposures is not well established, and few prospective cohort studies of recreational exposures to marine phytoplankton have been conducted.
  
  
  OBJECTIVE
  We evaluated the association between phytoplankton cell counts and subsequent illness among recreational beachgoers.
  
  
  METHODS
  We recruited beachgoers at Boquerón Beach, Puerto Rico, during the summer of 2009. We conducted interviews at three time points to assess baseline health, water activities, and subsequent illness. Daily water samples were quantitatively assayed for phytoplankton cell count. Logistic regression models, adjusted for age and sex, were used to assess the association between exposure to three categories of phytoplankton concentration and subsequent illness.
  
  
  RESULTS
  During 26 study days, 15,726 individuals successfully completed all three interviews. Daily total phytoplankton cell counts ranged from 346 to 2,012 cells/mL (median, 712 cells/mL). The category with the highest (≥ 75th percentile) total phytoplankton cell count was associated with eye irritation [adjusted odds ratio (OR) = 1.30; 95% confidence interval (CI): 1.01, 1.66], rash (OR = 1.27; 95% CI: 1.02, 1.57), and earache (OR = 1.25; 95% CI: 0.88, 1.77). In phytoplankton group-specific analyses, the category with the highest Cyanobacteria counts was associated with respiratory illness (OR = 1.37; 95% CI: 1.12, 1.67), rash (OR = 1.32; 95% CI: 1.05, 1.66), eye irritation (OR = 1.25; 95% CI: 0.97, 1.62), and earache (OR = 1.35; 95% CI: 0.95, 1.93).
  
  
  CONCLUSIONS
  We found associations between recreational exposure to marine phytoplankton and reports of eye irritation, respiratory illness, and rash. We also found that associations varied by phytoplankton group, with Cyanobacteria having the strongest and most consistent associations.
  
  
  BACKGROUND
  Lin CJ, Wade TJ, Sams EA, Dufour AP, Chapman AD, Hilborn ED. 2016. A prospective study of marine phytoplankton and reported illness among recreational beachgoers in Puerto Rico, 2009. Environ Health Perspect 124:477-483; http://dx.doi.org/10.1289/ehp.1409558.
authors.affiliation: Oak Ridge Institute for Science and Education (ORISE) Research Participation Program at the U.S. Environmental Protection Agency (EPA), Chapel Hill, North Carolina, USA.
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Lin
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Wade
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Sams
authors.forename: Alfred P
authors.initials: AP
authors.lastname: Dufour
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Chapman
authors.forename: Elizabeth D
authors.initials: ED
authors.lastname: Hilborn
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001493:Bathing Beaches / Q000706:statistics & numerical data*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D000458:Cyanobacteria / Q000302:isolation & purification; D004781:Environmental Exposure / Q000706:statistics & numerical data; D005076:Exanthema / Q000382:microbiology*; D005128:Eye Diseases / Q000382:microbiology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D010839:Phytoplankton / Q000302:isolation & purification*; D011446:Prospective Studies; D011647:Puerto Rico; D011998:Recreation; D012140:Respiratory Tract Diseases / Q000382:microbiology*; D012623:Seawater / Q000009:adverse effects / Q000382:microbiology*