TABLE 5.
Longitudinal regression model of ferritin*
| First time (FT) Females |
Frequent FT Females |
High intensity Females |
First time (FT) Males |
Deferred Males |
High intensity Males |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Description | n = 116 Estimate | d = 287 p value | n = 113 Estimate | d = 495 p value | n = 92 Estimate | d = 315 p value | n = 131 Estimate | d = 420 p value | n = 33 Estimate | d = 125 p value | n = 135 Estimate | d = 243 p value |
| TMPRSS6 Genotype | - | 0.0066 | - | 0.1089 | - | 0.5893 | - | 0.0131 | - | 0.1814 | - | 0.5361 |
| AA vs VV | 0.27 | 0.0016 | 0.11 | 0.0391 | −0.05 | 0.3368 | 0.07 | 0.1619 | −0.14 | 0.1229 | 0.05 | 0.3618 |
| AV vs VV | 0.21 | 0.0140 | 0.08 | 0.0909 | −0.02 | 0.6720 | −0.05 | 0.2833 | 0.01 | 0.9014 | <0.01 | 0.9888 |
| AA vs AV | 0.06 | 0.2668 | 0.03 | 0.4750 | −0.03 | 0.4533 | 0.12 | 0.0033 | −0.15 | 0.0881 | 0.05 | 0.3124 |
| C282Y wild type vs Ho/He | −0.04 | 0.6581 | −0.13 | 0.0212 | 0.12 | 0.0217 | 0.07 | 0.3661 | −0.18 | 0.0622 | −0.07 | 0.3635 |
| H63D wild type vs Ho/He | 0.04 | 0.4562 | 0.09 | 0.0178 | 0.05 | 0.2434 | −0.01 | 0.7100 | −0.10 | 0.2399 | −0.06 | 0.2517 |
| Race/ethnicity | - | 0.3642 | - | 0.2922 | - | 0.5141 | - | 0.0546 | - | - | - | 0.4585 |
| Asian vs White | 0.10 | 0.3455 | - | - | 0.06 | 0.6073 | 0.02 | 0.8659 | - | - | 0.07 | 0.5168 |
| Black vs White | 0.10 | 0.4900 | 0.03 | 0.8583 | 0.15 | 0.2986 | −0.11 | 0.2688 | - | - | - | - |
| Hispanic vs White | 0.17 | 0.1556 | −0.26 | 0.0560 | 0.15 | 0.2813 | 0.03 | 0.7930 | - | - | −0.11 | 0.3282 |
| Other vs White | −0.33 | 0.3503 | 0.02 | 0.9383 | - | - | 0.35 | 0.0056 | - | - | 0.13 | 0.2819 |
| Length of time since prev. visit | <0.01 | <.0001 | <0.01 | <.0001 | <0.01 | 0.0020 | <0.01 | <.0001 | <0.01 | 0.0291 | <0.01 | 0.0002 |
| # RBC donations in past 12m | −0.09 | 0.0013 | −0.06 | 0.0004 | −0.03 | 0.1683 | −0.07 | <.0001 | −0.03 | 0.2130 | −0.07 | <.0001 |
| Age (yrs) at baseline visit | 0.01 | 0.0084 | <0.01 | 0.0078 | <−0.01 | 0.6956 | <0.01 | 0.6931 | 0.02 | <.0001 | <0.01 | 0.0256 |
| Weight (lbs) at baseline visit | <0.01 | 0.2670 | <0.01 | <.0001 | <0.01 | 0.0929 | <0.01 | <.0001 | <−0.01 | 0.4543 | <0.01 | 0.4377 |
| Missing ferritin data count | −0.01 | 0.7530 | −0.01 | 0.6046 | 0.01 | 0.0930 | −0.06 | 0.1218 | 0.02 | 0.1339 | <−0.01 | 0.3039 |
| Iron supplementation | - | 0.0923 | - | 0.3874 | - | 0.0006 | - | 0.0005 | - | 0.3249 | - | 0.0020 |
| Daily vs none | 0.05 | 0.3532 | 0.05 | 0.2416 | 0.16 | 0.0002 | −0.14 | 0.0017 | 0.09 | 0.2781 | 0.18 | 0.0008 |
| Weekly vs none | 0.17 | 0.0323 | 0.05 | 0.3159 | 0.07 | 0.2583 | 0.16 | 0.0422 | −0.10 | 0.4053 | 0.12 | 0.0965 |
| Daily vs weekly | −0.12 | 0.1748 | <−0.01 | 0.9287 | 0.09 | 0.0979 | −0.30 | 0.0005 | 0.19 | 0.1567 | 0.05 | 0.5105 |
| Currently smoking: Yes vs No | −0.02 | 0.6811 | 0.12 | 0.0436 | 0.06 | 0.2775 | 0.13 | 0.0208 | −0.15 | 0.4979 | 0.12 | 0.1749 |
| Still menstrating: Yes vs No | −0.03 | 0.7099 | −0.06 | 0.2073 | −0.07 | 0.1951 | n/a | n/a | n/a | n/a | n/a | n/a |
Longitudinal multiple regression models of log10 ferritin (ng/mL) on 9 covariates and 3 genotypes for donors with two or more visits at which there was a donation or hemoglobin deferral.
Separate regression models were estimated, one for each blood donor analysis group. Results for the first five hemoglobin donations or deferrals were included in the model. The number of donors (n) and the number of donations (d) are included in each model is reported in the column headings. Parameter estimates rounded to two decimal places; p values are presented to four digits. The C282 and H63D genotypes were modeled as binary variables, with homozygous (Ho) and heterozygous (He) results combined so that these models would converge to a solution. Some levels of race are missing in certain analysis groups. Race was excluded from the model of deferred males due to a lack of representative data in this smaller group. For multiple-level categorical variables, an overall p value is presented along with the p values for differences in individual levels.