Epidemiological and clinical studies interested in circulating glucose as a risk factor or outcome typically measure levels in the blood at a single or widely spaced time points (e.g. every few years). While these are important health indicators, there has been an increasing appreciation that glucose levels and variability in free-living conditions during both the day and night, may also provide important health measures in clinical (e.g. diabetic or obese) and ‘healthy’ populations.

Continuous glucose monitoring (CGM) systems measure interstitial glucose levels ‘continuously’ by implanting a sensor subcutaneously. This produces a sequence of measurements for each participant (e.g. the average glucose level every 5 minutes over several days), that can be used to assess how a person’s glucose levels vary over both the day and night. We have recently published a novel software package called GLU, for deriving a consistent set of summary variables from CGM data. The derived summary variables can be used in analyses to assess how different characteristics of glucose levels and variability relate to health exposures and outcomes.