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Table 3 Final Covariates of Excluded and Modeled Participants

From: The association of remotely-sensed outdoor temperature with blood pressure levels in REGARDS: a cross-sectional study of a large, national cohort of African-American and white participants

Characteristics Missing Excluded Participants Participants in the Final Model P-value
  N N (%) N (%)  
Total   5245 (20%) 20773 (80%)  
Outcome Variables     
   SBP mmHg (SD) 0 127.8 (18.8) 128.2 (16.7) 0.20
   DBP mmHg (SD) 0 77.1 (22.8) 76.8 (9.6) 0.43
Meteorological Variables     
   Same day maximum temp, lower by 20°F (mean, SD) 0 70.4 (17.0) 70.6 (16.8) 0.52
   Same day minimum temp, lower by 20°F (mean, SD) 0 55.2 (17.1) 55.2 (16.8) 0.76
   Maximum temp variability, by SD increase (mean, SD) 0 2.0 (1.0) 2.0 (1.0) 0.008
   Minimum temp variability, by SD increase (mean, SD) 0 2.2 (1.0) 2.1 (1.0) <.0001
   Season     
Summer   1450 (28%) 5872 (28%)  
Fall 0 1400 (27%) 5721 (28%) 0.003
Winter   1289 (25%) 4601 (22%)  
Spring   1106 (21%) 4579 (22%)  
Demographics     
   Age, years (mean, SD)   65.3 (9.4) 65.7 (9.3) 0.004
   Male 5 2251 (43%) 9481 (46%) 0.0005
   Black Race 8 1926 (37%) 3311 (43%) <.0001
   Region     
Stroke Buckle   1195 (23%) 3605 (17%)  
Stroke Belt 0 2010 (38%) 7343 (35%) <.0001
Non-Belt   2040 (39%) 9825 (47%)  
   Population Density     
Urban   2916 (56%) 1952 (9%)  
Mixed 0 418 (8%) 2071 (10%) <.0001
Rural   1911 (36%) 16750 (81%)  
SES Factors     
   Education < = 8th Grade 24 726 (14%) 2686 (13%) 0.06
   Income     
< $20 k   1069 (20%) 3957 (19%)  
$20 k-$35 k 0 1318 (25%) 5112 (25%)  
$35 k-$75 k   1472 (28%) 6186 (30%) 0.0008
>= $75 k   721 (14%) 3135 (15%)  
refused   665 (13%) 2483 (12%)  
Health Behaviors     
   Smoking Status     
Never   2376 (46%) 9170 (44%)  
Current 97 764 (15%) 3045 (15%) 0.01
Past   2008 (39%) 8558 (41%)  
   Alcohol use (never) 0 1704 (32%) 6107 (29%) <.0001
Co-morbidities     
   BMI     
Underweight/Normal 362 1210 (25%) 5183 (25%)  
Overweight   1798 (37%) 7677 (40%) 0.92
Obese   1875 (38%) 7913 (38%)  
   Hyperlipidemia 19 4085 (78%) 18848 (91%) <.0001
   Diabetes 895 980 (23%) 4565 (22%) 0.42
  1. SBP = systolic blood pressure; DBP = diastolic blood pressure; SD = standard deviation; High Temp = high temperatures; Low Temp = low temperatures
  2. P-values for categorical variables provided from a chi squared test statistic
  3. P-Values provided from a pooled t-test statistic or Satterwaithe t-test calculated for each variable by inclusion status. The test was chosen depending on the results for a Folded f equality of variances test.