Table 4.
Regression line equations
| Y | Unita | Equation no. | n b | Intercept (α) | Slope (β) | r | P for r |
|---|---|---|---|---|---|---|---|
| Case Ac | (group-based analysis) | ||||||
| Cd-D | μg/kg BW/day | ||||||
| Total cases | 1 | 23 | 38.140 | −0.0189 | −0.586 | p < 0.01 | |
| Selected casesf | 2 | 18 | 21.025 | −0.0103 | −0.329 | p > 0.05 | |
| Cd-B | μg/L | 3 | 51 | 105.139 | −0.0518 | −0.575 | p < 0.01 |
| Cd-Bg | μg/L | 4 | 50 | 75.207 | −0.0369 | −0.625 | p < 0.01 |
| Cd-Ucr | μg/g cr | 5 | 33 | 90.183 | −0.0443 | −0.490 | p < 0.01 |
| Case Bd | (group-based analysis with adjustment) | ||||||
| Cd-D | μg/kg BW/day | ||||||
| Total cases | 6 | 23 | 37.688 | −0.0187 | −0.522 | p < 0.05 | |
| Selected casesf | 7 | 18 | 11.702 | −0.0057 | −0.152 | p > 0.05 | |
| Cd-B | μg/L | 8 | 51 | 101.003 | −0.0498 | −0.583 | p < 0.01 |
| Cd-Bg | μg/L | 9 | 50 | 67.782 | −0.0332 | −0.585 | p < 0.01 |
| Cd-Ucr | μg/g cr | 10 | 33 | 79.049 | −0.0388 | −0.426 | p < 0.05 |
| Case Ce | (number-weighted analysis) | ||||||
| Cd-D | μg/kg BW/day | 11 | 7146 | 40.435 | −0.0200 | −0.630 | p < 0.01 |
| Cd-B | μg/L | 12 | 35,385 | 81.492 | −0.0400 | −0.461 | p < 0.01 |
| Cd-Bg | μg/L | 13 | 35,313 | 60.503 | −0.0296 | −0.411 | p < 0.01 |
| Cd-Ucr | μg/g cr | 14 | 10,260 | 84.707 | −0.0417 | −0.484 | p < 0.01 |
In the equation Y = α + βX, X is the year of survey and Y is the parameter shown in the table
aUnit for Y
bNumber of groups in Case A and Case B, and number of individuals in Case C
cCase A: the publication year is taken as the survey year when the survey year is not reported
dCase B: in absence of report on the survey year, the survey year is estimated by subtracting 5.5, 5.5 and 3.0 years from the publication year in cases of Cd-D, Cd-B and Cd-Ucr, respectively. There is no significant difference (p > 0.05) in intercepts, slopes and correlation coefficients between Eqs. 1 and 6, Eqs. 2 and 7, Eqs. 3 and 8, Eqs. 4 and 9, and Eqs. 5 and 10
eCase C: calculation was made as in Case A, except that the analysis is made in a number-weighted manner taking the number of individuals into consideration
fFive studies are not included because the Cd-D is estimated taking advantage of e.g., national statistics of food consumptions and the number of participating subjects are not available
gAfter exclusion of one group of extreme cases (p < 0.01 by Smirnov’s test for extreme value)