Seasonal variations could impact blood glucose levels, Australian researchers report

Blood glucose levels are more likely to be higher in the winter and spring compared to autumn and summer, an Australian study finds.
Researchers at the School of Public Health, University of Queensland, analysed data from 49,417 adults participating in the Kailuan cohort study – a prospective community-based analysis of retired Tangshan employees of a China-based coal mining company.
Fasting plasma glucose (FPG), blood pressure and history of diabetes were collected for each participant. 77.6 per cent of the cohort was male, and 7.9 per cent had a history of diabetes.
The daily weather conditions were collected between 2006 and 2011 – participants who had three consultations during this period were included in the analyses. Controlled variables such as sex, age, BMI, diabetes status, physical activity and alcohol intake were considered.
Levels of FPG were found to be higher in winter and spring and lower in autumn and summer. All participants had higher FPG levels in winter and lowest FPG levels in autumn. These differences were greater among participants with diabetes, but no differences were observed in regard to age or sex.
The researchers also noted mean changes in FPG levels were higher when associated with extreme cold temperature and extreme hot temperature compared to moderate cold temperature and moderate hot temperature.
“Understanding the seasonality in markers, such as lipids, fibrinoge, blood pressure and FPG, is helpful to explore the reason for seasonality in the morbidity and mortality of diseases,” the authors wrote.
“Accumulating evidence has shown that FPG, lipids, fibrinogen and [BP] usually have a tendency to be higher in winter than in summer. Such seasonal variability might be driven from cold air temperatures, which increase activation of the sympathetic nerve system and secretion of catecholamine.”
The study was published in Diabetes Metabolism.