title: Short- and long-term sunlight radiation and stroke incidence.
abstract: OBJECTIVE
  Examine whether long- and short-term sunlight radiation is related to stroke incidence.
  
  
  METHODS
  Fifteen-year residential histories merged with satellite, ground monitor, and model reanalysis data were used to determine sunlight radiation (insolation) and temperature exposure for a cohort of 16,606 stroke and coronary artery disease-free black and white participants aged ≥45 years from the 48 contiguous United States. Fifteen-, 10-, 5-, 2-, and 1-year exposures were used to predict stroke incidence during follow-up in Cox proportional hazard models. Potential confounders and mediators were included during model building.
  
  
  RESULTS
  Shorter exposure periods exhibited similar, but slightly stronger relationships than longer exposure periods. After adjustment for other covariates, the previous year's monthly average insolation exposure below the median gave a hazard ratio (HR) of 1.61 (95% confidence interval [CI], 1.15-2.26), and the previous year's highest compared to the second highest quartile of monthly average maximum temperature exposure gave an HR of 1.92 (95%, 1.27-2.92).
  
  
  CONCLUSIONS
  These results indicate a relationship between lower levels of sunlight radiation and higher stroke incidence. The biological pathway of this relationship is not clear. Future research will show whether this finding stands, the pathway for this relationship, and whether it is due to short- or long-term exposures.
authors.affiliation: Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, USA. shia@uab.edu
authors.forename: Shia T
authors.initials: ST
authors.lastname: Kent
authors.forename: Leslie A
authors.initials: LA
authors.lastname: McClure
authors.forename: Suzanne E
authors.initials: SE
authors.lastname: Judd
authors.forename: Virginia J
authors.initials: VJ
authors.lastname: Howard
authors.forename: William L
authors.initials: WL
authors.lastname: Crosson
authors.forename: Mohammad Z
authors.initials: MZ
authors.lastname: Al-Hamdan
authors.forename: Virginia G
authors.initials: VG
authors.lastname: Wadley
authors.forename: Fredrick
authors.initials: F
authors.lastname: Peace
authors.forename: Edmond K
authors.initials: EK
authors.lastname: Kabagambe
mesh_terms: D044383:Black People; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology* / Q000401:mortality / Q000517:prevention & control*; D013472:Sunlight; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D044465:White People; D001741:Black or African American