In a study published in PLoS Biology on 8 May, 2025 scientists analysed more than 300 papers that used data from the US National Health and Nutrition Examination Survey (NHANES), an open data set of health records. The papers all seemed to follow a similar template, associating one variable – for example, vitamin D levels or sleep quality – with a complex disorder such as depression or heart disease, ignoring the fact that these conditions have many contributing factors.
Study co-author Matt Spick, a biomedical scientist at the University of Surrey in Guildford, UK, and his colleagues found that the associations in many of the papers did not hold up to statistical scrutiny, and that some studies seemed to have cherry-picked data. Analysis flags hundreds of studies that seem to follow a template, reporting correlations between complex health conditions and single variables based on publicly available data sets.
