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Table 1 Characteristics of the Study Cohort within the REasons for Geographic and Racial Differences in Stroke (REGARDS) Study by Climate Region

From: Association between temperature exposure and cognition: a cross-sectional analysis of 20,687 aging adults in the United States

Characteristic Dry Continental Tropics Mediterranean/oceanic Overall
N (%), unless otherwise specified
Participants (N) 485 5026 13,494 1682 20,687
Age, mean (SD), yearsa 68.9 (9.5) 68.3 (9.3) 67.5 (9.1) 68.3 (9.8) 67.8 (9.2)
Sex, female 247 (50.9) 2711 (53.9) 7794 (57.8) 1024 (60.9) 11,776 (56.9)
Race, Black 43 (8.9) 2111 (42.0) 5062 (37.5) 759 (45.1) 7975 (38.6)
Education
 Less than high school 13 (2.7) 461 (9.2) 1478 (11.0) 58 (3.5) 2010 (9.7)
 High school graduate 92 (19.0) 1355 (27.0) 3490 (25.9) 231 (13.7) 5168 (25.0)
 Some College 140 (28.9) 1347 (26.8) 3569 (26.5) 515 (30.6) 5571 (26.9)
 College graduate and above 240 (49.5) 1863 (37.1) 4957 (36.7) 878 (52.2) 7938 (38.4)
Temperature on day of test in °C, mean (SD)b 15.2 (9.1) 10.6 (10.8) 17.5 (8.4) 15.5 (6.2) 15.6 (9.4)
Composite cognitive score, meanc 0.1 (0.9) −0.05 (0.9) −0.09 (1.0) 0.05 (0.9) − 0.06 (1.0)
  1. Abbreviations: N number, SD standard deviation
  2. Climate regions were created based on the climate groups within Köppen climate region classification system. Individuals residing in Humid Subtropical climates were combined with those living in the Tropics to form one group and the Mediterranean and Oceanic climates were grouped to form the Mediterranean/oceanic climate region, to ensure adequate sample size
  3. a Age at the time of the first available Word List Learning (WLL) and Word List Delayed (WLD) recall test score over the course of the study from 2006 to 2016
  4. b Temperature was computed as the mean of minimum and maximum temperature reading on the day of the cognitive assessment for each weather station, and averaged across all the National Oceanic and Atmospheric Administration (NOAA) weather stations in the county of the participant
  5. c Score was generated by averaging the z-scores for the WLL and WLL-D in the entire cohort
  6. Participant characteristics (age, race, sex and education) were self-reported at the time of the baseline interview between 2003 and 2007