Article characteristics, study outcome | Crude OR | Adjusted ORa |
 Authors’ conclusion (pos vs neg) | 1.4 (0.9–2.3) | 1.8 (1.1–2.9) |
 Data-based conclusion (pos vs neg)b | 1.4 (0.8–2.3) | – |
Article characteristics, other content-related | Crude OR | Adjusted ORa |
 Article type (empirical vs narrative) | 4.2 (2.6–6.7) | – |
 Sample size (ref: low)b | ||
  medium | 4.2 (2.1–8.4) | – |
  high | 5.8 (2.9–11.6) | – |
 Study quality (fair vs poor)c | 1.6 (0.7–3.2) | 1.4 (0.6–3.0) |
 Specificity (cont) | 1.3 (1.1–1.6) | 1.4 (1.2–1.7) |
Article characteristics, not content-related | Crude OR | Adjusted ORa |
 Language | d | d |
 Conclusive title (yes vs no) | 1.3 (0.9–2.0) | 1.2 (0.8–1.8) |
 Funding source (ref: exclusively non-profit) | ||
  profit or both profit/non-profit | 1.6 (0.9–2.6) | 1.6 (0.9–2.7) |
  not reported | 0.2 (0.1–0.4) | 0.3 (0.2–0.5) |
 Number of authors (ref: 1 – 2) | ||
  3 – 4 | 2.2 (1.2–4.0) | 2.1 (1.2–4.0) |
  5 – 6 | 6.0 (3.0–11.9) | 3.2 (1.5–6.6) |
  ≥ 7 | 2.9 (1.6–5.1) | 1.7 (0.9–3.2) |
 Number of affiliations (ref: 1) | ||
  2 | 2.0 (1.2–3.3) | 1.7 (1.0–2.9) |
  ≥ 3 | 2.2 (1.4–3.4) | 1.4 (0.9–2.3) |
 Number of references (ref: < 25) | ||
  25 – 40 | 4.7 (2.6–8.6) | 3.3 (1.7–6.1) |
  ≥ 40 | 5.1 (2.7–9.6) | 5.1 (2.6–9.8) |
 Journal impact factor (ref: 0 – 2) | ||
  2 – 4 | 0.5 (0.3–0.9) | 0.7 (0.4–1.1) |
  ≥ 4 | 1.9 (1.2–3.1) | 2.0 (1.2–3.3) |
Author characteristics | Crude OR | Adjusted ORa |
 Gender (female vs male) | 0.8 (0.5–1.2) | 0.6 (0.4–0.9) |
 Country (ref: Belgium) | ||
  Other North West Europe | 0.8 (0.4–1.7) | 0.9 (0.4–1.9) |
  South Europe | 0.4 (0.2–0.7) | 0.4 (0.2–0.7) |
  North America | 0.4 (0.2–1.0) | 0.3 (0.1–0.7) |
 Type of affiliation (other vs university) | 1.1 (0.7–1.8) | 0.8 (0.5–1.4) |
Citation characteristics | Crude OR | Adjusted ORa |
 Time to citation (cont, in years) | 1.0 (1.0–1.1) | 1.0 (0.9–1.1) |
 Authority (ref: low) | ||
  medium | 2.4 (1.5–4.0) | 2.8 (1.7–4.6) |
  high | 4.1 (2.2–7.8) | 4.1 (2.1–8.0) |
 Self-citation (yes vs no)e | 4.6 (2.8–7.5) | 5.2 (3.1–8.8) |