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Aims/Introduction Several cross‐sectional studies have shown that delayed heart rate recovery (HRR) after exercise is associated with the development of metabolic syndrome (MetS). However, there has been a lack of comprehensively designed longitudinal studies. Therefore, our aim was to evaluate the longitudinal association of delayed HRR following a graded exercise treadmill test (GTX) with incident MetS. Materials and Methods This was a retrospective longitudinal cohort study of participants without MetS, diabetes, or cardiovascular diseases. The HRR was calculated as the peak heart rate minus the resting heart rate after a 1 min rest (HRR1), a 2 min rest (HRR2), and a 3 min rest (HRR3). Multivariate Cox proportional hazards analysis was performed to investigate the association between HRR and development of MetS. Results There were 676 (31.2%) incident cases of MetS identified during the follow‐up period (9,683 person‐years). The only statistically significant relationship was between HRR3 and the development of MetS. The hazard ratios (HRs) (95% confidence interval [CI]) of incident MetS comparing the first and second tertiles to the third tertile of HRR3 were 1.492 (1.146–1.943) and 1.277 (1.004–1.624) with P = 0.003 after adjustment for multiple risk factors. As a continuous variable, the HR (95% CI) of incident MetS associated with each one‐beat decrease in HRR3 was 1.015 (1.005–1.026) with P = 0.004 after full adjustments. An HRR3 value ≤45 beats per minute (bpm) was associated with a higher risk of incident MetS compared with values >45 bpm, with an HR (95% CI) of 1.304 (1.061–1.602) and P = 0.001. Conclusions The slow phase of HRR, particularly HRR3, might be more sensitive at predicting the risk of MetS., Delayed HRR3 after exercise could predict incident MetS in a general population, even after adjusting for fasting plasma glucose, HOMA‐IR, and HbA1c. And a HRR3 value of 45 beats per minute (bpm) or below was associated with a significantly higher risk of incident MetS compared with values over 45 bpm.

Aims/Introduction To evaluate whether hemoglobin A1c (HbA1c) levels are affected by hemoglobin level and gender. Materials and Methods A cross-sectional analysis was carried out in a sample of 87,284 non-diabetic Koreans without anemia who participated in comprehensive health check-ups between January and December 2009 at the Kangbuk Samsung Hospital Total Healthcare Center in Seoul, Korea. We categorized men and women separately according to fasting plasma glucose and hemoglobin level to carry out the analysis. Results HbA1c increased steadily with increasing fasting plasma glucose level. Both men and women with lower hemoglobin had significantly higher HbA1c at a given fasting glucose level, and this result was consistent across the fasting glucose quintiles within the non-diabetic range. Women had a lower mean hemoglobin value compared with men, and women had higher HbA1c levels at a given fasting glucose level consistently across the fasting glucose deciles. There was also a gender-specific association between age and HbA1c (P

Aims/Introduction Small dense low-density lipoprotein (sdLDL) has been suggested to be a potential risk factor for cardiovascular diseases (CVD). Materials and Methods We carried out a prospective nested case–control study in the Korean Health and Genome Study. Participants were men and women aged 40–69 years who developed CVD (n = 313), and were matched by age and sex to controls who remained free of CVD (n = 313) during the 8-years follow-up period (from 2001 to 2009). LDL subfractions were analyzed in frozen samples collected from the 626 participants using polyacrylamide tube gel electrophoresis. Results Patients with CVD had a significantly higher glycated hemoglobin level compared with the controls (5.72 vs 5.56). The proportion of patients with diabetes mellitus (DM) was higher in those who developed CVD during follow up (8.0% vs 1.9%). The frequency of CVD according to each tertile of LDL particle size and the number of metabolic syndrome components did not differ significantly. In the multivariate analysis, DM (odds ratio 4.244, 95% confidence interval 1.693–10.640, P = 0.002) was the only independent predictive factor of CVD. LDL particle size was not associated with the risk for future CVD. Conclusions Small dense LDL might not be a significant predictor of CVD in this Korean community-based prospective cohort study.