Table 1.
Distribution of demographics and potential covariates by creatinine-adjusted urinary Pb quartile.
| Total | Quartile 1 | Quartile 2 | Quartile 3 | Quartile 4 | |
|---|---|---|---|---|---|
|
| |||||
| Exposure | N | Range (N) | Range (N) | Range (N) | Range (N) |
| Creatinine-adjusted urinary Pb (pg/L) | 696 | 0.03–0.24 (174) | 0.24–0.39 (174) | 0.39–0.60 (174) | 0.60–15.31 (174) |
| Categorical covariates | N | n (%) | n (%) | n (%) | n (%) |
| Age§ | 696 | ||||
| 18–29 | 58 | 36 (62.1) | 19 (32.6) | 2 (3.4) | 1 (1.7) |
| 30–49 | 172 | 84 (48.8) | 49 (28.4) | 19 (11.0) | 20 (11.6) |
| 50–69 | 339 | 49 (14.5) | 78 (23) | 115 (33.9) | 97 (28.6) |
| ≥ 70 | 127 | 5 (3.9) | 28 (22) | 38 (29.9) | 56 (44.1) |
| Gender† | 696 | ||||
| Female | 399 | 87 (21.8) | 90 (22.6) | 106 (26.6) | 116 (29.1) |
| Male | 297 | 87 (29.3) | 84 (28.3) | 68 (22.9) | 58 (19.5) |
| Race/ethnicity | 695 | ||||
| Non-Hispanic White | 577 | 138 (23.9) | 145 (25.1) | 153 (26.5) | 141 (24.4) |
| Non-Hispanic Black | 70 | 21 (30.0) | 20 (28.6) | 14 (20.0) | 15 (21.4) |
| Hispanic | 24 | 9 (37.5) | 6 (25.0) | 3 (12.5) | 6 (25.0) |
| Non-Hispanic other | 24 | 5 (20.8) | 3 (12.5) | 4 (16.7) | 12 (50.0) |
| Family income | 696 | ||||
| Low income | 204 | 49 (24.0) | 52 (25.5) | 47 (23.0) | 56 (27.5) |
| Middle income | 220 | 62 (28.2) | 53 (24.1) | 51 (23.2) | 54 (24.5) |
| High income | 272 | 63 (23.2) | 69 (25.4) | 76 (27.9) | 64 (23.5) |
| Education* | 695 | ||||
| ≤ High School | 187 | 34 (18.2) | 49 (26.2) | 47 (25.1) | 57 (30.5) |
| Some college | 247 | 56 (22.7) | 65 (26.3) | 64 (25.9) | 62 (25.1) |
| ≥ Bachelor’s degree | 261 | 84 (32.2) | 60 (23.0) | 63 (24.1) | 54 (20.7) |
| Smoking§ | 685 | ||||
| Current | 93 | 14 (15.1) | 30 (32.3) | 21 (22.6) | 28 (30.1) |
| Former | 205 | 33 (16.1) | 51 (24.9) | 59 (28.8) | 62 (30.2) |
| Never | 387 | 123 (31.8) | 93 (24.0) | 91 (23.5) | 80 (20.7) |
| Antibiotic use | 653 | ||||
| Yes | 228 | 58 (25.4) | 58 (25.4) | 51 (22.4) | 61 (26.8) |
| No | 425 | 104 (24.5) | 109 (25.6) | 117 (27.5) | 95 (22.4) |
| Indoor pet† | 693 | ||||
| Yes | 379 | 115 (30.3) | 97 (25.6) | 84 (22.2) | 83 (21.9) |
| No | 314 | 58 (18.5) | 77 (24.5) | 90 (28.7) | 89 (28.3) |
| BMI | 690 | ||||
| Underweight/normal | 165 | 40 (24.2) | 38 (23.0) | 42 (25.5) | 45 (27.3) |
| Overweight/obese | 525 | 133 (25.3) | 136 (25.9) | 131 (25.0) | 125 (23.8) |
| Urbanicity | 695 | ||||
| Urban | 460 | 119 (25.9) | 124 (27.0) | 109 (23.7) | 108 (23.5) |
| Suburban | 76 | 23 (30.3) | 15 (19.7) | 20 (26.3) | 18 (23.7) |
| Rural | 159 | 32 (20.1) | 34 (21.4) | 45 (28.3) | 48 (30.2) |
| Length of residence§ | 688 | ||||
| < 1 year | 62 | 23 (37.1) | 19 (30.6) | 12 (19.5) | 8 (12.9) |
| 1–3 years | 105 | 35 (33.3) | 31 (29.5) | 20 (19.0) | 19 (18.1) |
| 3–10years | 145 | 50 (34.5) | 42 (29.0) | 27 (18.6) | 26 (17.9) |
| > 10years | 376 | 64 (17.0) | 82 (21.8) | 112 (29.8) | 118 (31.4) |
| Continuous covariates | N | Mean ± SE | Mean ± SE | Mean ± SE | Mean ± SE |
| Dietary iron (mg/1000 Kcal) | 615 | 7.6 ± 0.24 | 7.3 ± 0.17 | 7.9 ± 0.2 | 7.6 ± 0.18 |
| Dietary calcium (mg/1000 Kcal) | 615 | 719.4 ± 42.56 | 732.8 ± 32.94 | 771.5 ± 39.57 | 799.2 ± 43.84 |
| Dietary fiber* (g/1000 Kcal) | 615 | 9.5 ± 0.3 | 10.2 ± 0.36 | 12.3 ± 0.41 | 11.9 ± 0.41 |
| Dietary vitamin C (mg/1000 Kcal) | 615 | 52 ± 2.81 | 59 ± 2.94 | 66.3 ± 3.34 | 64.2 ± 3.17 |
Data come from the microbiome study sample of the Survey of the Health of Wisconsin 2016–2017. Urinary Pb geometric mean statistics are not adjusted for creatinine concentration or household clustering. Categorical distribution statistics calculated using frequency tables adjusted for household clustering, including p-values from the χ2 statistic. Continuous covariate statistics calculated including adjustment for household clustering, including p for trend.
*
P≤0.05
†
P≤0.01.
§
P≤0.0001.