High Glucose and Low Insulin Sensitivity: Linked to Reduced Lung Function
Adults without diabetes or lung disease who present with higher glucose levels and impaired insulin sensitivity experience reduced lung function, according to a cross-sectional study presented at the EASD Congress. The research evaluated 2,507 participants aged 50–64 years from the Umeå site of the Swedish CArdioPulmonary bioImage Study (SCAPIS), all of whom underwent spirometry, diffusing capacity measurement, and an oral glucose tolerance test.
The investigation examined several metabolic markers—including glycated haemoglobin (HbA1c), fasting glucose, 2-hour glucose, fasting insulin, insulin sensitivity, insulin secretion, and insulin clearance—while adjusting the analysis for age, sex, smoking, physical activity, education, and waist circumference.
Associations With Glucose and Insulin Measures
Higher 2-hour glucose concentrations were linked to lower forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1). HbA1c demonstrated a nonlinear inverse association with diffusing capacity for carbon monoxide (DLco) and FEV1, showing steeper declines above approximately 37 mmol/mol (5.5%). Higher fasting insulin levels were likewise associated with lower FVC and FEV1.
Conversely, greater insulin sensitivity—measured via the Matsuda index—was associated with higher FVC, DLco, and FEV1. Insulin clearance showed a positive association with FVC, whereas higher insulin secretion displayed an inverse association with DLco.
Implications for Early Metabolic Risk Assessment
The findings revealed that modest elevations in HbA1c and postprandial glucose, sitting below current diagnostic thresholds for prediabetes, align with diminished pulmonary measurements. These patterns led researchers to suggest that the lung may act as an early target of metabolic disturbances.
The study concluded that early assessment of metabolic risk could hold relevance for preserving pulmonary function among adults without diabetes or established lung disease, with reduced insulin clearance potentially pointing toward a role for hepatic metabolic dysfunction.