Allon Raphael1, Michael Friger2, Aya Biderman3. 1. Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheba, Israel. Electronic address: allonra@post.bgu.ac.il. 2. Department of Public Health, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheba, Israel. Electronic address: friger@bgu.ac.il. 3. Department of Family Medicine and Siaal Center for Community Research, Division of Community Health, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Clalit Health Services, Southern District, Beer-Sheva, Israel. Electronic address: abid@bgu.ac.il.
Abstract
AIMS: To investigate the seasonal variations of HbA1c values in a semi-arid climate among type 2 diabetic patients throughout 11 years of care. METHODS: A retrospective cohort study of 2860 patients with 61,187 HbA1c measures. We calculated the averages of HbA1c values of all patients and sub-groups defined by age, gender, BMI, ethnicity, insulin use, smoking status and region of residence, matched to the mean temperature and diurnal range over the 30 and 60 days prior to the HbA1c test date. RESULTS: We found a sinusoidal seasonal pattern with statistically significant HbA1c levels gaps between the spring peak and the autumn trough (F = 18.4, P < 0.001). The lowest values were in October-November and the highest in March or August with a difference of 0.17-0.31% (2-4 mmol/mol). We found different relations between the mean temperature and HbA1c depending on season, gender, age, ethnicity and smoking habits. CONCLUSION: The study identified specific subgroups in which the seasonal influence is particularly marked. A possible explanation is that during hot periods people tend to change their diet and decrease their physical activity, effecting indirectly diabetic imbalance. Recognition of the seasonal variations of HbA1c levels in this geographical region could help physicians with diabetes care and HbA1c control.
AIMS: To investigate the seasonal variations of HbA1c values in a semi-arid climate among type 2 diabeticpatients throughout 11 years of care. METHODS: A retrospective cohort study of 2860 patients with 61,187 HbA1c measures. We calculated the averages of HbA1c values of all patients and sub-groups defined by age, gender, BMI, ethnicity, insulin use, smoking status and region of residence, matched to the mean temperature and diurnal range over the 30 and 60 days prior to the HbA1c test date. RESULTS: We found a sinusoidal seasonal pattern with statistically significant HbA1c levels gaps between the spring peak and the autumn trough (F = 18.4, P < 0.001). The lowest values were in October-November and the highest in March or August with a difference of 0.17-0.31% (2-4 mmol/mol). We found different relations between the mean temperature and HbA1c depending on season, gender, age, ethnicity and smoking habits. CONCLUSION: The study identified specific subgroups in which the seasonal influence is particularly marked. A possible explanation is that during hot periods people tend to change their diet and decrease their physical activity, effecting indirectly diabetic imbalance. Recognition of the seasonal variations of HbA1c levels in this geographical region could help physicians with diabetes care and HbA1c control.
Authors: Mike Z He; Itai Kloog; Allan C Just; Iván Gutiérrez-Avila; Elena Colicino; Martha M Téllez-Rojo; María Luisa Pizano-Zárate; Marcela Tamayo-Ortiz; Alejandra Cantoral; Diana C Soria-Contreras; Andrea A Baccarelli; Robert O Wright; Maayan Yitshak-Sade Journal: Environ Int Date: 2022-05-14 Impact factor: 13.352