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Table 2 Demographics, Socioeconomic Status, and Behavioral Characteristics by Income Levels from NHANES 1999–2002

From: Income, inflammation and cancer mortality: a study of U.S. National Health and Nutrition Examination Survey mortality follow-up cohorts

Characteristics Total (N = 2344) Low Income (N = 904) Middle Income (N = 830) High Income (N = 610) P-value
Age (years)      < 0.001a
 Median (Range) 52 (40–84) 55 (40–84) 53 (40–84) 51 (40–84)  
 Younger than 55 yrs 55.5% 48.5% 51.7% 64.0%  
 55 yrs. or older 44.5% 51.5% 48.3% 36.0%  
Race/Ethnicity      < 0.001a
 White 74.5% 60.5% 71.7% 87.3%  
 Black 10.6% 14.9% 12.5% 5.9%  
 Hispanics/Other 14.8% 24.6% 15.8% 6.8%  
Gender      0.03a
 Male 48.4% 43.7% 50.1% 50.4%  
 Female 51.6% 56.3% 49.9% 49.6%  
Education      < 0.001a
 Below High School 24.3% 46.2% 24.3% 8.5%  
 High School/Equivalent 25.2% 27.8% 28.0% 20.8%  
 Above High School 50.4% 26.0% 47.7% 70.7%  
Occupation      < 0.001a
 Not Working 2.1% 4.8% 2.2% 0.2%  
 White Collar and Professional 32.1% 17.1% 25.4% 49.1%  
 White Collar, Semi-Routine 23.6% 17.4% 24.6% 27.2%  
 Blue Collar, High Skill 13.4% 15.5% 15.4% 10.0%  
 Blue Collar, Semi-Routine 28.8% 45.1% 32.3% 13.5%  
Body Mass Index (kg/m2)      0.64a
 Median (Range) 27.7 (12.0–66.4) 28.1 (15.8–66.4) 27.9 (12.0–63.9) 27.4 (16.5–61.2)  
 Underweight 1.1% 1.5% 1.1% 0.9%  
 Normal 27.7% 26.8% 26.8% 29.1%  
 Overweight 37.4% 34.7% 39.4% 37.5%  
 Obese 33.8% 37.0% 32.6% 32.5%  
Smoking      0.002a
 Never 45.5% 44.4% 43.1% 48.5%  
 Former 31.7% 26.2% 34.2% 33.5%  
 Current 22.8% 29.4% 22.7% 18.0%  
Physical Activityb      0.001a
 More Active 40.6% 36.0% 44.7% 40.2%  
 Less Active 20.8% 27.1% 19.3% 17.7%  
 About Same 38.6% 37.0% 36.0% 42.1%  
C-Reactive Protein      < 0.001a
 Mean (Range) 0.45 (0.01–7.83) 0.52 (0.01–7.83) 0.46 (0.01–6.90) 0.39 (0.01–6.80)  
  < 0.22 mg/dL 44.9% 38.9% 43.7% 50.5%  
 0.22–0.99 mg/dL 44.2% 45.5% 45.3% 42.2%  
  > 0.99 mg/dL 10.9% 15.5% 11.1% 7.3%  
Fibrinogen      0.003c
 Mean (Range) 367 (120–808) 385 (173–808) 371 (177–747) 351 (120–715)  
  1. a Chi-Square tests were performed for categorical variables
  2. b Physical activity compared to others of the same age
  3. c t-tests were performed for the continuous variables