Issues in the reporting of epidemiological studies: a survey of recent practice.
OBJECTIVE
To review current practice in the analysis and reporting of epidemiological research and to identify limitations.


METHODS
Examination of articles published in January 2001 that investigated associations between risk factors/exposure variables and disease events/measures in individuals.


METHODS
Eligible English language journals including all major epidemiological journals, all major general medical journals, and the two leading journals in cardiovascular disease and cancer.


METHODS
Each article was evaluated with a standard proforma.


RESULTS
We found 73 articles in observational epidemiology; most were either cohort or case-control studies. Most studies looked at cancer and cardiovascular disease, even after we excluded specialty journals. Quantitative exposure variables predominated, which were mostly analysed as ordered categories but with little consistency or explanation regarding choice of categories. Sample selection, participant refusal, and data quality received insufficient attention in many articles. Statistical analyses commonly used odds ratios (38 articles) and hazard/rate ratios (23), with some inconsistent use of terminology. Confidence intervals were reported in most studies (68), though use of P values was less common (38). Few articles explained their choice of confounding variables; many performed subgroup analyses claiming an effect modifier, though interaction tests were rare. Several investigated multiple associations between exposure and outcome, increasing the likelihood of false positive claims. There was evidence of publication bias.


CONCLUSIONS
This survey raises concerns regarding inadequacies in the analysis and reporting of epidemiological publications in mainstream journals.
Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London WC1E 7HT. stuart.pocock@lshtm.ac.uk
Stuart J
SJ
Pocock
Timothy J
TJ
Collier
Kimberley J
KJ
Dandreo
Bianca L
BL
de Stavola
Marlene B
MB
Goldman
Leslie A
LA
Kalish
Linda E
LE
Kasten
Valerie A
VA
McCormack
D015986:Confounding Factors, Epidemiologic; D015987:Effect Modifier, Epidemiologic; D004781:Environmental Exposure; D015340:Epidemiologic Research Design; D016021:Epidemiologic Studies; D006801:Humans; D010506:Periodicals as Topic