Table 1.

Demographic Characteristics of NHANES 1999-2002 Participants Aged 50-84 Years by Usual Source of Care (n = 3175), Percent for Categorical Variables and Standard Error for Continuous Variables in Parenthesis

VariableFull Sample (n = 3175)Usual Source of Care
Yes (n = 2953)No (n = 222)P-Value
Mean telomere length (base pair)5564.9 (37.4)5569.2 (37.5)5500.1 (44.9).041
Mean Age (years)62.9 (0.2)63.2 (0.2)59.0 (0.7)<.001
Mean WBC count (millions/µL)7.0 (0.1)7.0 (0.1)7.4 (0.2).105
Gender.018
 Male1606 (46.3)1475 (45.7)131 (55.5)
 Female1569 (53.7)1478 (54.3)91 (44.5)
Race/ethnicity<.001
 Non-Hispanic White1851 (81.3)1769 (82.2)82 (67.9)
 Non-Hispanic Black467 (6.9)441 (6.9)26 (7.9)
 Mexican American and Hispanic782 (8.6)673 (7.8)109 (21.1)
 Other races75 (3.2)70 (3.1)5 (3.1)
Education level.009
 Less than high school1195 (24.6)1063 (23.7)132 (38.9)
 High school721 (26.1)683 (26.2)38 (24.0)
 Some college656 (24.7)626 (25.0)30 (19.8)
 College and above603 (24.6)581 (25.1)22 (17.2)
Covered by health insurance
 Yes2874 (92.6)2755 (94.7)119 (60.6)<.001
 No301 (7.4)198 (5.3)103 (39.4)
CVD History<.001
 Yes599 (16.9)583 (17.5)16 (6.6)
 No2576 (83.1)2370 (82.5)206 (93.4)
Emphysema history.163
 Yes97 (3.5)96 (3.7)1 (1.0)
 No3078 (96.5)2857 (96.3)221 (99.0)
High blood pressure<.001
 Yes1493 (43.6)1443 (45.2)50 (18.1)
 No1682 (56.4)1510 (54.8)172 (81.9)
Smoking status<.001
 Current smoker491 (16.7)419 (15.3)72 (38.1)
 Former smoker1240 (39.0)1178 (39.9)62 (25.8)
 Never smoked1444 (44.3)1356 (44.8)88 (36.1)
Physical inactivity.003
 Yes1592 (43.3)1454 (42.3)138 (58.9)
 No1583 (56.7)1499 (57.7)84 (41.1)
  • CVD, cardiovascular disease; WBC, white blood cell; NHANES, National Health and Nutrition Examination Survey.

  • Values are number of subjects (weighted proportion) for categorical variables or weighted means (standard error) for continuous variables. P-values were calculated using weighted χ2 tests or t-test.