Variation in Urinary Flow Rates According to Demographic Characteristics and Body Mass Index in NHANES: Potential Confounding of Associations between Health Outcomes and Urinary Biomarker Concentrations

http://dx.doi.org/10.1289/ehp.1408944



Table 2. GM UFR (mL/hr) from NHANES 2009–2012 by age group, sex, race/ethnic group, and BMI categories.
Mean 6–11 years 12–19 years 20–39 years 40–59 years ≥ 60 years
GM (95% CI) p-Valuea GM (95% CI) p-Valuea GM (95% CI) p-Valuea GM (95% CI) p-Valuea GM (95% CI) p-Valuea
ap-Values present comparison to reference group within each age stratum for each categorization (sex, race/ethnic group, or BMI category), except as otherwise indicated. bCompared with ages 20–39 years.
All 33.3 (31.4, 35.3) < 0.001b 42.5 (40.7, 44.4) < 0.001b 51.1 (48.5, 53.8) Reference 51.9 (50.2, 53.6) 0.6b 43.2 (41.5, 44.9) < 0.001b
Sex
Male (reference) 33.6 (31.6, 35.9) Reference 44.5 (42.0, 47.2) Reference 54.5 (51.9, 57.3) Reference 55.1 (52.5, 57.9) Reference 47.4 (44.7, 50.2) Reference
Female 33.0 (30.3, 35.9) 0.7 40.5 (38.1, 43.0) 0.02 47.9 (44.7, 51.4) < 0.001 49.0 (47.2, 50.8) < 0.001 40.0 (37.9, 42.3) < 0.001
Race/ethnic group
Mexican American 31.5 (28.7, 34.7) 0.1 41.9 (38.7, 45.5) 0.3 44.8 (41.5, 48.3) < 0.001 43.8 (40.4, 47.4) < 0.001 37.5 (33.0, 42.6) 0.02
Non-Hispanic White 35.0 (32.0, 38.3) Reference 44.3 (41.3, 47.6) Reference 55.7 (52.3, 59.2) Reference 54.9 (52.7, 57.2) Reference 44.3 (42.3, 46.5) Reference
Non-Hispanic Black 31.1 (28.1, 34.4) 0.09 36.9 (33.8, 40.2) < 0.001 38.8 (36.9, 40.9) < 0.001 42.5 (40.3, 44.9) < 0.001 37.9 (35.9, 40.0) < 0.001
Other 33.9 (28.9, 39.8) 0.7 43.9 (39.7, 48.7) 0.9 52.9 (48.7, 57.5) 0.2 52.3 (45.9, 59.5) 0.5 41.6 (36.4, 47.6) 0.3
BMI
< 20 (reference) 32.2 (30.0, 34.6) Reference 40.6 (37.0, 44.5) Reference 46.0 (39.5, 53.6) Reference 54.4 (44.7, 66.3) Reference 39.0 (32.3, 47.2) Reference
20 to < 25 37.3 (32.9, 42.3) 0.04 42.4 (39.6, 45.5) 0.4 52.6 (48.4, 57.1) 0.09 56.5 (52.1, 61.1) 0.7 41.4 (37.4, 45.8) 0.6
25 to < 30 38.4 (33.5, 44.1) 0.03 43.5 (39.7, 47.6) 0.3 52.1 (47.6, 57.1) 0.2 52.1 (48.8, 55.6) 0.7 45.3 (41.7, 49.3) 0.2
≥ 30 25.7 (19.8, 33.3) 0.1 45.2 (40.7, 50.1) 0.1 49.7 (46.9, 52.7) 0.3 48.9 (47.1, 50.8) 0.3 42.6 (40.5, 44.9) 0.4