Table 1. Summary statistics of analytic sample at baseline, HRS (n = 1089).
These statistics are shown separately by lead exposure status. We classified respondents from cities that had lead pipes and extreme levels of water pH (acidic or alkaline), the conditions required for lead to leach into drinking water, as exposed. Because, for cities that did not use lead pipes or that had neutral water, lead cannot leach into drinking water regardless of water pH, we considered the rest of respondents unexposed. We performed significant group comparisons based on chi-square test, Kruskal-Wallis test, and t test.
| Percentage (N) or mean (SD) | |||||
| Exposed | Nonexposed | ||||
| Full sample | Lead pipes and acidic/alkaline water (7.07%; N = 77) | Lead pipes and neutral water (36.18%; N = 394) | Nonlead pipes (56.75%; N = 618) | P value | |
| Cognitive score (0–27) | 17.29 (4.02) | 16.10 (4.14) | 17.65 (4.08) | 17.22 (3.94) | P < 0.01 |
| Standardized cognitive score | 0.61 (0.87) | 0.35 (0.90) | 0.68 (0.89) | 0.59 (0.86) | P < 0.01 |
| Lead pipes (%) | 43.25 (471) | ||||
| Acidic/alkaline water (%) | 10.47 (114) | ||||
| Age (57–93) | 65.49 (5.01) | 65.52 (4.81) | 65.41 (4.95) | 65.54 (5.08) | P = 0.92 |
| Female (%) | 50.69 (552) | 45.45 (35) | 55.33 (218) | 48.38 (299) | P = 0.06 |
| Race/ethnicity (%) | P = 0.07 | ||||
| Non-Hispanic, white | 88.89 (968) | 97.40 (75) | 89.59 (353) | 87.38 (540) | |
| Non-Hispanic, Black | 7.99 (87) | 2.60 (2) | 7.87 (31) | 8.74 (54) | |
| Hispanic | 2.30 (25) | – | 1.27 (5) | 3.24 (20) | |
| Other | 0.83 (9) | – | 1.27 (5) | 0.65 (4) | |
| Childhood SES (%) | P = 0.63 | ||||
| 0 | 45.55 (496) | 40.26 (31) | 44.67 (176) | 46.76 (289) | |
| 1 | 24.24 (264) | 31.17 (24) | 23.35 (92) | 23.95 (148) | |
| 2 | 17.26 (188) | 18.18 (14) | 17.77 (70) | 16.83 (104) | |
| 3+ | 12.95 (141) | 10.39 (8) | 14.21 (56) | 12.46 (77) | |
| Poor childhood health (%) | 7.07 (77) | 10.39 (8) | 7.61 (30) | 6.31 (39) | P = 0.37 |
| Southern born (%) | 16.53 (180) | 2.60 (2) | 19.80 (78) | 16.18 (100) | P < 0.001 |
| Educational attainment (%) | P < 0.05 | ||||
| <High school | 12.30 (134) | 20.78 (16) | 10.41 (41) | 12.46 (77) | |
| High school | 39.12 (426) | 44.16 (34) | 40.10 (158) | 37.86 (234) | |
| Some college | 20.75 (226) | 12.99 (10) | 19.4 (77) | 22.49 (139) | |
| College+ | 27.82 (303) | 22.08 (17) | 29.95 (118) | 27.18 (168) | |
| Income (1–10) | 6.24 (2.63) | 5.96 (2.48) | 5.90 (2.62) | 6.49 (2.64) | P < 0.01 |
| Wealth (1–10) | 6.43 (2.66) | 6.34 (2.52) | 6.44 (2.67) | 6.42 (2.68) | P = 0.96 |
| Ever had stroke (%) | 4.41 (48) | 3.90 (3) | 4.57 (18) | 4.37 (27) | P = 0.96 |
| Ever had hypertension | 41.05 (447) | 33.77 (26) | 41.88 (165) | 41.42 (256) | P = 0.40 |
| Ever had heart diseases | 15.98 (174) | 18.18 (14) | 15.99 (63) | 15.70 (97) | P = 0.85 |