Logistic regression of article-level factors associated with authorship parasitism
| Article with any local authors, n (%) | Article without local authors, n (%) | OR (95% CI) | P value | Adjusted OR (95% CI)* | P value | |
| Journal publisher region | ||||||
| Sub-Saharan Africa | 2719 (10.0) | 220 (4.6) | Referent | Referent | ||
| East Asia and Pacific | 219 (0.8) | 48 (1.1) | 2.71 (1.91 to 3.78) | <0.001 | 1.84 (1.24 to 2.71) | 0.002 |
| Europe and Central Asia | 14 333 (52.5) | 2792 (58.7) | 2.41 (2.09 to 2.78) | <0.001 | 1.43 (1.22 to 1.68) | <0.001 |
| Latin America and the Caribbean | 37 (0.1) | 16 (0.3) | 5.34 (2.85 to 9.59) | <0.001 | 2.78 (1.13 to 6.39) | 0.020 |
| Middle East and North Africa | 137 (0.5) | 22 (0.4) | 1.98 (1.21 to 3.11) | <0.001 | 1.03 (0.58 to 1.75) | 0.913 |
| North America | 9462 (34.7) | 1629 (34.3) | 2.13 (1.84 to 2.47) | <0.001 | 1.26 (1.07 to 1.50) | 0.006 |
| South Asia | 400 (1.4) | 27 (0.6) | 0.83 (0.54 to 1.23) | 0.389 | 0.84 (0.52 to 1.30) | 0.450 |
| Language of article | ||||||
| English | 26 577 (97.3) | 4675 (98.3) | Referent | Referent | ||
| French | 703 (2.5) | 37 (0.8) | 0.29 (0.21 to 0.41) | <0.001 | 0.60 (0.41 to 0.85) | 0.006 |
| Other languages or multiple languages | 27 (0.2) | 42 (0.9) | 8.84 (5.41 to 14.51) | <0.001 | 9.40 (4.86 to 18.78) | <0.001 |
| Study country income group | ||||||
| Upper-middle income† | 5213 (19.1) | 484 (10.2) | Referent | Referent | ||
| Lower-middle income | 11 822 (43.3) | 2084 (43.9) | 1.90 (1.71 to 2.11) | <0.001 | 2.05 (1.83 to 2.30) | <0.001 |
| Low-income | 8653 (31.7) | 1237 (26.0) | 1.54 (1.38 to 1.72) | <0.001 | 1.76 (1.57 to 1.99) | <0.001 |
| Multicountry study | 1604 (5.9) | 946 (19.9) | 6.35 (5.62 to 7.19) | <0.001 | 8.41 (7.30 to 9.68) | <0.001 |
| Funding agency type | ||||||
| US government | 4384 (16.1) | 704 (14.8) | 0.86 (0.79 to 0.94) | <0.001 | 0.79 (0.63 to 0.98) | 0.033 |
| Non-US government | 354 (1.3) | 86 (1.8) | 1.31 (1.02 to 1.65) | 0.002 | 0.99 (0.76 to 1.29) | 0.957 |
| Private foundation | 1671 (6.1) | 148 (3.1) | 0.48 (0.40 to 0.56) | <0.001 | 0.84 (0.65 to 1.07) | 0.161 |
| Other* | 595 (2.2) | 92 (1.9) | 0.83 (0.66 to 1.03) | 0.103 | 0.53 (0.43 to 0.64) | <0.001 |
| Multiple types | 903 (3.3) | 115 (2.4) | 0.68 (0.56 to 0.83) | <0.001 | 0.86 (0.77 to 0.96) | 0.005 |
| None listed | 19 400 (71.0) | 3609 (76.0) | Referent | Referent | ||
| Number of authors | ||||||
| <5 | 7820 (28.6) | 2614 (55.0) | 4.64 (4.20 to 5.15) | <0.001 | 14.46 (12.81 to 16.35) | <0.001 |
| 5–10 | 12 699 (46.5) | 1652 (34.7) | 1.81 (1.63 to 2.01) | <0.001 | 2.80 (2.50 to 3.15) | <0.001 |
| >10 | 6788 (24.9) | 488 (10.3) | Referent | Referent | ||
| Any group author | ||||||
| No | 26 409 (96.7) | 4625 (97.3) | Referent | Referent | ||
| Yes | 898 (3.3) | 129 (2.7) | 0.82 (0.67 to 0.98) | 0.04 | 1.09 (0.88 to 1.34) | 0.439 |
| High-income country affiliated authors outside sub-Saharan Africa | ||||||
| None | 9240 (33.8) | 404 (8.5) | Referent | Referent | ||
| High-income country (not UK or USA) | 5320 (19.5) | 1482 (31.2) | 6.37 (5.68 to 7.16) | <0.001 | 8.16 (7.04 to 9.47) | <0.001 |
| At least one UK affiliation | 3211 (11.8) | 604 (12.7) | 4.30 (3.77 to 4.91) | <0.001 | 10.28 (9.06 to 11.68) | <0.001 |
| At least one US affiliation | 8005 (29.3) | 1999 (42.0) | 5.71 (5.11 to 6.39) | <0.001 | 13.02 (10.77 to 15.72) | <0.001 |
| At least one US and UK affiliations | 1531 (5.6) | 265 (5.6) | 3.96 (3.36 to 4.66) | <0.001 | 12.88 (11.33 to 14.67) | <0.001 |
*Candidate variables in which the p value was <0.2 in the univariable model were included in the multivariable model.
†Includes two high-income countries in sub-Saharan Africa (ie, Equatorial Guinea and Seychelles).