International Journal of Biometeorology

, Volume 58, Issue 3, pp 361–370 | Cite as

The relationship between long-term sunlight radiation and cognitive decline in the REGARDS cohort study

  • Shia T. KentEmail author
  • Edmond K. Kabagambe
  • Virginia G. Wadley
  • Virginia J. Howard
  • William L. Crosson
  • Mohammad Z. Al-Hamdan
  • Suzanne E. Judd
  • Fredrick Peace
  • Leslie A. McClure
Original Paper


Sunlight may be related to cognitive function through vitamin D metabolism or circadian rhythm regulation. The analysis presented here sought to test whether ground and satellite measures of solar radiation are associated with cognitive decline. The study used a 15-year residential history merged with satellite and ground monitor data to determine sunlight (solar radiation) and air temperature exposure for a cohort of 19,896 cognitively intact black and white participants aged 45+ from the 48 contiguous United States. Exposures of 15, 10, 5, 2, and 1-year were used to predict cognitive status at the most recent assessment in logistic regression models; 1-year insolation and maximum temperatures were chosen as exposure measures. Solar radiation interacted with temperature, age, and gender in its relationships with incident cognitive impairment. After adjustment for covariates, the odds ratio (OR) of cognitive decline for solar radiation exposure below the median vs above the median in the 3rd tertile of maximum temperatures was 1.88 (95 % CI: 1.24, 2.85), that in the 2nd tertile was 1.33 (95 % CI: 1.09, 1.62), and that in the 1st tertile was 1.22 (95 % CI: 0.92, 1.60). We also found that participants under 60 years old had an OR = 1.63 (95 % CI: 1.20, 2.22), those 60–80 years old had an OR = 1.18 (95 % CI: 1.02, 1.36), and those over 80 years old had an OR = 1.05 (0.80, 1.37). Lastly, we found that males had an OR = 1.43 (95 % CI: 1.22, 1.69), and females had an OR = 1.02 (0.87, 1.20). We found that lower levels of solar radiation were associated with increased odds of incident cognitive impairment.


Sunlight Temperature Weather Climate Remote sensing technology Cognition 



The authors thank the other investigators, the staff, and the participants of the REGARDS study for their valuable contributions. A full list of participating REGARDS investigators and institutions can be found at This research project is supported by a cooperative agreement U01 NS041588 from the National Institute of Neurological Disorders and Stroke. Additional funding, data, data processing, and consultation were provided by an investigator-initiated grant from National Aeronautics and Space Administration (grant# NNX09AV81G). The NLDAS hourly data used in this study were acquired as part of the mission of National Aeronautics and Space Administration’s Earth Science Division and archived and distributed by the Goddard Earth Sciences Data and Information Services Center.


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Copyright information

© ISB 2013

Authors and Affiliations

  • Shia T. Kent
    • 1
    • 2
    Email author
  • Edmond K. Kabagambe
    • 1
  • Virginia G. Wadley
    • 3
  • Virginia J. Howard
    • 1
  • William L. Crosson
    • 4
  • Mohammad Z. Al-Hamdan
    • 4
  • Suzanne E. Judd
    • 2
  • Fredrick Peace
    • 2
  • Leslie A. McClure
    • 2
  1. 1.Department of Epidemiology, School of Public HealthUniversity of Alabama at BirminghamBirminghamUSA
  2. 2.Department of Biostatistics, School of Public HealthUniversity of Alabama at BirminghamBirminghamUSA
  3. 3.Department of MedicineUniversity of Alabama at BirminghamBirminghamUSA
  4. 4.NASA Marshall Space Flight CenterNational Space Science and Technology CenterHuntsvilleUSA

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