Table 1.

Prevalence of periodontal disease,^a prevalence difference, and prevalence ratio estimates for selected sociodemographic characteristics in U.S. adults 20 years of age and older within and between surveys: NHANES III (1988–1994) and NHANES 1999–2004

^aPrevalence (SEs) of periodontal disease (defined as at least one site with pocket depth ≥4 millimeters [mm] and at least one site with clinical attachment loss ≥3 mm) for adults 20 years of age and older. All p-values for Chi-square tests within and between surveys were <0.01 except for nativity status in NHANES III.

^bPrevalence difference and ratio compare NHANES 1999–2004 with NHANES III (1988–1994).

^cp<0.01 for t-test assessing the difference between the prevalence of each level of the characteristic and the level assigned as the reference

^dp<0.05 for t-test assessing the difference between the prevalence of each level of the characteristic and the level assigned as the reference

^eLow, medium, and high categories for income were <$14,999, $15,000–$24,999, and ≥$25,000 in NHANES III and <$19,999, $20,000–$44,999, and ≥$45,000 in NHANES 1999–2004, respectively.

NHANES = National Health and Nutrition Examination Survey

SE = standard error

CI = confidence interval

NA = not applicable