Synergistic Effects of 1 h Post-Load Plasma Glucose and Smoking on Arterial Stiffness in Apparently Healthy Men: A Cross-sectional Study

Aim: One-hour post-load plasma glucose (1h-PG) during an oral glucose tolerance test and smoking are associated with arterial stiffness. However, it remains unknown whether there are synergistic effects of these two factors on arterial stiffness. This study aimed to investigate the interaction between 1h-PG and smoking in relation to brachial–ankle pulse wave velocity (baPWV) in young men with normal glucose tolerance (NGT). Methods: The study included 25-, 30-, 35-, 40-, and 45-year-old non-industrial male workers (n = 2189) who underwent a detailed health check-up. Normotensive participants with NGT and taking no medication were included. Results: A univariate linear regression analysis showed that 1h-PG correlated with baPWV (r = 0.13, p < 0.001), but the correlation was not significant in the multivariate analysis (β = 0.02, p = 0.24). However, we found a significant interaction between 1h-PG levels and smoking status in relation to baPWV (p = 0.048). Therefore, further analyses were conducted in nonsmokers and smokers. A multivariate linear regression analysis revealed that 1h-PG significantly correlated with baPWV in smokers (β = 0.11, p = 0.02), but not in nonsmokers (β = 0.01, p = 0.79). The correlation remained significant even after adjustment for the number of cigarettes smoked per day (β = 0.096, p = 0.048) or the Brinkman index (β = 0.097, p = 0.043). Conclusion: A significant interaction between 1h-PG and smoking in relation to baPWV was found in apparently healthy men younger than 50 years old.