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Table 1 Summary of cohort studies included in the review

From: A review of the reporting and handling of missing data in cohort studies with repeated assessment of exposure measures

Characteristics Number of studies (N = 82) (%)
Publication year
2000 2 (2)
2001 4 (5)
2002 4 (5)
2003 5 (6)
2004 6 (7)
2005 8 (10)
2006 11 (13)
2007 13 (16)
2008 13 (16)
2009 16 (20)
Number of participants recruited at baseline
Not stated in paper 4 (5)
1,000–2,000 15 (18)
2,000–3,000 13 (16)
3,000–5,000 14 (17)
5,000–10,000 13 (16)
10,000–20,000 14 (17)
20,000 + 9 (11)
Date of baseline recruitment (decade recruitment started)
Not stated in paper 5 (6)
Before 1970 9 (11)
1970–1979 9 (11)
1980–1989 25 (30)
1990–1999 30 (37)
2000–2009 4 (5)
Number of follow-up waves used in the analysis
Number not stated 12 (15)
Mean or range given 7 (9)
1 10 (12)
2 9 (11)
3 18 (22)
4 12 (15)
≥5 14 (17)
Statistical methods for epidemiological analysis†
Cox proportional hazards regression^ 37‡  
  Time-varying covariates 35  
  Time-invariant covariates 3  
Generalised Estimating Equations 12*  
  Linear regression 3  
  Logistic regression 10  
Generalised linear mixed-effects modelling 16  
  Linear regression 13  
  Logistic regression 3  
Standard linear regression 3  
Standard logistic regression 9  
Other methods 6  
  1. † The total number of papers is 83 because one paper used two analysis models: a Cox proportional hazards model for a time to event outcome and a linear mixed effects model for a numerical outcome.
  2. ^ Note one paper used a parametric survival model.
  3. ‡ One paper incorporated their repeated measures of exposures using both a time varying covariate and time-invariant covariates.
  4. *One paper had a numerical and binary outcome.