Objective: Cardiovascular autonomic neuropathy (CAN) is a common complication of type 1 diabetes (DM1). The risk of CAN is lower in middle-aged healthy women than in men, a fact that might be related to a more dominant parasympathetic regulation in the former. This sex-related effect in favor of women appears to disappear beyond 50 year-old. We assessed the effects of age and sex on CAN in patients with DM1.

Research Designs and Methods: Cross-sectional study in 281 consecutive patients (158 males and 123 females) with DM1. CAN was assessed by the Ewing Score using the variability of heart rate (HR) in response to deep breathing, standing, and the Valsalva’s maneuver, and the response of blood pressure to active standing. A composite score ≥ 1 was diagnostic of CAN. CAN was classified as early or mild when the Ewing score was between 1-2, and definitive when ≥ 2.

Results: The mean age of our study population was 36±12 years-old and their average duration of DM1 was 20±11 years. Their mean HbA1cwas 7.6±1.3%. The global prevalence of CAN was 30.6% (25.5-36.2). CAN was categorized as early/mild in 79 (92%) cases and definitive in 7 (8%) cases. CAN prevalence was not significantly different between men and women when analyzing all subjects regardless of age. When age was taken into account, the prevalence of CAN was independent of sex among individuals below 50 year-old, but in subjects aged ≥ 50 years (21 males and 19 females) the prevalence of CAN was larger in women than in men [63.2% (41.0-80.9) vs. 23.8% (10.6-45.1), respectively; χ2: 6.32, p= 0.012]. The OR of having CAN was 5.5 (1.4-21.6) in women aged ≥ 50 years compared to their male counterparts and 3.9 (1.4-10.7) compared to women under 50 years.

Conclusions: The increase in CAN risk in subjects with type 1 DM may be greater in women over 50 years than in men of similar age. Moreover, women aged ≥ 50 years-old associate to a higher risk of CAN than younger women and men. This finding might be related to the menopausal-related decline in sex steroids.


L. Nattero-Chávez: None. S. Alonso Diaz: None. L. Montanez: None. E. Fernández: None. S. Redondo Lopez: None. M. Garnica Ureña: None. A. Bayona: None. H. Escobar-Morreale: None. M. Luque Ramírez: None.


Instituto de Salud Carlos III, Spanish Ministry of Economy and Competitiveness (PI1400649, PI151686, PIE1600050); Fondo Europeo de Desarrollo Regional

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