Table 1.
Characteristics of study participants.
| Characteristic | Cohort | Total | ||||
|---|---|---|---|---|---|---|
| A | B | C | D | E | ||
| Recruitment start year | 1987 | 1994 | 1997 | 2001 | 2007 | |
| Years included in study | 1988–1998 | 1995–1999 | 1998–2007 | 2002–2008 | 2008–2015 | |
| Number of participants | 291 | 457 | 240 | 382 | 593 | 1963 |
| Girls, n (%) | 129 (44) | 202 (44) | 122 (51) | 190 (50) | 293 (49) | 936 (48) |
| Maternal Education, n (%) | ||||||
| Primary | 55 (19) | 94 (21) | 27 (11) | 28 (7) | 17 (3) | 219 (11) |
| Technical secondary | 107 (38) | 239 (53) | 113 (47) | 212 (56) | 229 (39) | 900 (46) |
| Secondary | 74 (26) | 69 (15) | 68 (29) | 89 (23) | 212 (36) | 512 (26) |
| Technical high school | 42 (15) | 43 (10) | 27 (11) | 49 (13) | 128 (22) | 289 (15) |
| High school or college | 3 (1) | 7 (1) | 4 (2) | 2 (1) | 7 (1) | 23 (2) |
| Number of Blood Samples for Each Age | ||||||
| 1 year old | 247 | 212 | 199 | 268 | 165 | 1091 |
| 2 years old | 219 | 306 | 206 | 318 | 245 | 1294 |
| 3 years old | 191 | 228 | 179 | 251 | - | 849 |
| 4 years old | 185 | 263 | 194 | 188 | 251 | 1081 |
| 5 years old | 151 | - | 184 | 80 | 245 | 660 |
| Total number of samples | 993 | 1009 | 962 | 1105 | 906 | 4975 |
| Main Exposures | ||||||
| Pb in air, mean (µg/m3), (SD) * | 0.56 (0.41) | 0.14 (0.04) | 0.08 (0.01) | 0.06 (0.01) | 0.03 (0.00) | |
| Use of Pb-glazed ceramics, yes (%) | 115 (41) | 200 (47) | 82 (35) | 88 (23) | 193 (33) | 678 (36) |
Note: Percentages may not add up to exactly 100%, owing to the rounding off; * Pb in air was measured from 1988 to 2013.