Use of analysis methods in original articles on risk factors and health outcomes published in the European Respiratory Journal, 2010–2013
| Analysis methods used | Details | Publication year | ||||
| 2010 | 2011 | 2012 | 2013 | Total | ||
| Total number of studies retrieved | Epidemiological original studies looking at risk factor–disease associations | 49 (100) | 40 (100) | 44 (100) | 22 (100) | 155 (100) |
| Simple methods | ||||||
| Statistical significance tests | Chi-squared test, Fisher's exact test, Student's t-test, ANOVA | 47 (96) | 37 (93) | 40 (91) | 20 (91) | 144 (93) |
| Simple regression methods | Logistic, linear, Poisson and Cox regressions | 33 (67) | 27 (68) | 34 (77) | 18 (82) | 112 (72) |
| Regression methods for repeated outcomes | GEEs, linear mixed models | 7 (14) | 5 (13) | 8 (18) | 1 (5) | 21 (14) |
| Regressions adjusted for confounders | 22 (45) | 15 (38) | 20 (45) | 14 (64) | 71 (46) | |
| Multivariate methods | Principal component analysis, cluster analysis, factor analysis, co-inertia analysis | 4 (8) | 2 (5) | 1 (2) | 0 (0) | 7 (5) |
| Causal multivariate methods | Cross-lag modelling, path analysis, Bayesian networks | 0 (0) | 0 (0) | 1 (2) | 0 (0) | 1 (1) |
Data are presented as n (%) studies investigating risk factor–outcome associations. We performed an OVID Medline search, which targeted only the European Respiratory Journal, and only original research articles from observational epidemiological studies (i.e. we excluded meta-analyses, reviews, historical articles, consensus development conferences, guidelines, randomised controlled trials, clinical trials, comment, biographies and editorial). The term “epidemiolo*” was added as research term across all fields. We carefully examined the methods section of each article, removed duplicates, and retained only studies that looked at associations between risk factor(s) and outcome(s). GEE: generalised estimating equation.