Alignment between 24-hour light and activity rhythms is associated with diabetes and glucose metabolism in a nationally representative sample of American adults
The alignment between environmental stimuli (e.g., light) and behavior cycles (e.g., rest-activity) is an essential feature of the circadian timing system, a key contributor to metabolic health. However, no previous studies have investigated light-activity alignment in relation to glycemic control in human populations.
Research Design and Methods
The analysis included ~7000 adults (age 20-80) from the National Health and Nutrition Examination Survey (2011-2014) with actigraphy-measured multi-day 24-hour activity and light data. We used phasor analysis to derive phasor magnitude and phasor angle, which measure coupling strength and phase difference between the activity-rest and light-dark cycles, respectively. We used multinomial logistic regression and multiple linear regression to study phasor magnitude and phasor angle in relation to diabetes (primary outcome), and multiple secondary biomarkers of glycemic control.
Lower alignment strength (i.e., a shorter phasor magnitude) and more delayed activity relative to the light cycle (i.e., a larger phasor angle) were both associated with diabetes. Specifically, compared to individuals in the quintiles indicating the most proper alignment (Q5 for phasor magnitude and Q1 for phasor angle), those in the quintiles with the most impaired alignment had a >70% increase in the odds of diabetes (Odds Ratio (95% confidence intervals), 1.76 (1.39, 2.24) for phasor magnitude and 1.73 (1.34, 2.25) for phasor angle). Similar associations were observed for biomarkers for glucose metabolism. The results were generally consistent across diverse sociodemographic and obesity groups.
The alignment pattern between 24-hour activity-rest and light-dark cycles may be a critical factor in metabolic health.