In the Journals

Glucose variability indices vary with age, alcohol consumption

In a random sample of adults without diabetes, aging was associated with increasing glucose variability indices, whereas alcohol consumption was associated with decreased variability indices, independent of fasting glucose, BMI, smoking and physical activity, according to a cross-sectional study.

“Determining the distribution of glycemic variability indices in general populations is important for interpreting reference values,” Francisco Gude, MD, PhD, of the clinical epidemiology unit at the Clínico Universitario de Santiago, Travesia de Choupana, Spain, and colleagues wrote. “Since the aim of treating diabetes is to restore glycemia to that of persons without diabetes, the generation of a metric of glycemic excursions should begin with an examination of the profiles of individuals without diabetes. It is also crucial to define the boundary beyond which [glucose variability indices] take on a pathological significance.”

Gude and colleagues analyzed data from 622 adults participating in a 6-day glucose monitoring period as part of AEGIS, a cross-sectional study conducted in the municipality of A Estrada in northwestern Spain (mean age, 48 years; 62% women; 12% previously diagnosed with diabetes). Researchers assessed five glycemic variability indices: standard deviation; mean amplitude of glycemic excursions (MAGE); mean absolute glucose change per patient per hour; continuous overlapping net glycemic action at 1 hour (CONGA1); and the mean of daily differences. Within the cohort, 581 completed at least 2 days of monitoring with a continuous glucose monitor (iPro, Medtronic). Participants completed the International Physical Activity Questionnaire and provided blood samples for HbA1c analysis; alcohol and tobacco consumption were also assessed.

Among adults without diabetes, index distributions were not normal but skewed to the right, according to researchers. They observed no between-sex differences for glucose variability indices, but age-related differences were observed for standard deviation, MAGE and CONGA1 indices.

Adults who consumed at least 140 g per week of alcohol had the lowest glucose variability indices vs. other categories of alcohol consumption; former smokers had the lowest standard deviation levels vs. other categories of tobacco consumption. There were no associations observed between BMI or physical activity and glucose variability indices.

In distributional regression models that adjusted for age, sex, BMI, alcohol intake, smoking status and physical activity, all indices were positively and independently associated with fasting glucose levels and negatively with heavy drinking, according to researchers.

“An interesting finding of our study is that, in free living conditions, consumers without diabetes of more than 140 g of alcohol per week showed lower [glucose variability indices] than did abstainers without diabetes and light drinkers,” the researchers wrote. “Alcohol consumption is a recognized risk factor for hypoglycemia in individuals with type 1 diabetes, and a recent meta-analysis showed that moderate alcohol consumption decreased fasting insulin concentrations among subjects without diabetes.”

The researchers noted that the reference value database does not include outcome data.

“Whether the reference values should be used as cutoff values for treatment remains to be discussed,” the researchers wrote. “Prospective studies and clinical trials are needed to determine whether percentile-based [glucose variability indices] have a role in identifying patients at higher risk of developing cardiovascular complications. Taken together with the long time span of recruitment, this could increase the scattering of the reference values provided; on the other hand, however, it also improves the external validity of our results.” – by Regina Schaffer

Disclosure: This work was supported by a grant from Medtronic.

In a random sample of adults without diabetes, aging was associated with increasing glucose variability indices, whereas alcohol consumption was associated with decreased variability indices, independent of fasting glucose, BMI, smoking and physical activity, according to a cross-sectional study.

“Determining the distribution of glycemic variability indices in general populations is important for interpreting reference values,” Francisco Gude, MD, PhD, of the clinical epidemiology unit at the Clínico Universitario de Santiago, Travesia de Choupana, Spain, and colleagues wrote. “Since the aim of treating diabetes is to restore glycemia to that of persons without diabetes, the generation of a metric of glycemic excursions should begin with an examination of the profiles of individuals without diabetes. It is also crucial to define the boundary beyond which [glucose variability indices] take on a pathological significance.”

Gude and colleagues analyzed data from 622 adults participating in a 6-day glucose monitoring period as part of AEGIS, a cross-sectional study conducted in the municipality of A Estrada in northwestern Spain (mean age, 48 years; 62% women; 12% previously diagnosed with diabetes). Researchers assessed five glycemic variability indices: standard deviation; mean amplitude of glycemic excursions (MAGE); mean absolute glucose change per patient per hour; continuous overlapping net glycemic action at 1 hour (CONGA1); and the mean of daily differences. Within the cohort, 581 completed at least 2 days of monitoring with a continuous glucose monitor (iPro, Medtronic). Participants completed the International Physical Activity Questionnaire and provided blood samples for HbA1c analysis; alcohol and tobacco consumption were also assessed.

Among adults without diabetes, index distributions were not normal but skewed to the right, according to researchers. They observed no between-sex differences for glucose variability indices, but age-related differences were observed for standard deviation, MAGE and CONGA1 indices.

Adults who consumed at least 140 g per week of alcohol had the lowest glucose variability indices vs. other categories of alcohol consumption; former smokers had the lowest standard deviation levels vs. other categories of tobacco consumption. There were no associations observed between BMI or physical activity and glucose variability indices.

In distributional regression models that adjusted for age, sex, BMI, alcohol intake, smoking status and physical activity, all indices were positively and independently associated with fasting glucose levels and negatively with heavy drinking, according to researchers.

“An interesting finding of our study is that, in free living conditions, consumers without diabetes of more than 140 g of alcohol per week showed lower [glucose variability indices] than did abstainers without diabetes and light drinkers,” the researchers wrote. “Alcohol consumption is a recognized risk factor for hypoglycemia in individuals with type 1 diabetes, and a recent meta-analysis showed that moderate alcohol consumption decreased fasting insulin concentrations among subjects without diabetes.”

The researchers noted that the reference value database does not include outcome data.

“Whether the reference values should be used as cutoff values for treatment remains to be discussed,” the researchers wrote. “Prospective studies and clinical trials are needed to determine whether percentile-based [glucose variability indices] have a role in identifying patients at higher risk of developing cardiovascular complications. Taken together with the long time span of recruitment, this could increase the scattering of the reference values provided; on the other hand, however, it also improves the external validity of our results.” – by Regina Schaffer

Disclosure: This work was supported by a grant from Medtronic.