Long-term detraining increases the risk of metabolic syndrome in Japanese men.

OBJECTIVE: The aim of the present study was to examine the effect of long-term detraining on metabolic syndrome (MetS). METHODS: 1109 Japanese men were categorized by their exercise habits. Clinical data, number of MetS risk factors, and differences in lifestyle-related behaviors of the non-training group (n = 233) and the detraining group (n = 483) were compared with those of the training group (n = 87). RESULTS: Waist circumference and body mass index were significantly higher in the non-training group and the detraining group than in the training group, and also higher in the detraining group than in the non-training group. High-density lipoprotein cholesterol (HDL-C) was lower and low-density lipoprotein cholesterol (LDL-C) was higher in the non-training group and the detraining group than in the training group. Both the non-training group and the detraining group had more MetS risk factors than the training group. The odds ratio for smoking was higher in the detraining group than in the training group. CONCLUSIONS: Detraining results in similar degrees of obesity, low HDL-C, high LDL-C, and high MetS risk as non-training. To prevent lifestyle-related diseases, it is particularly important not only to encourage adults to become physically active, but also discourage active young people from discontinuing physical exercise.

Significance of high HDL cholesterol levels in Japanese men with metabolic syndrome.

OBJECTIVE: The objective was to clarify the significance of high high-density lipoprotein cholesterol (HDL-C) levels in the metabolic syndrome (MetS). The evaluation focused on insulin resistance as an indicator of early-stage MetS. METHODS AND SUBJECTS: Of 2705 men who first underwent an annual health check-up at Tokai University Hachioji Hospital, 2129 men were included in this study, after exclusion of those on medication for hypertension, diabetes or dyslipidemia, and those with a prior history of ischemic heart disease, cerebrovascular disease or chronic renal failure. MetS risk factors include the following five parameters: waist circumference, blood pressure, plasma glucose, triglycerides and HDL-C. The correlations between HDL-C and number of MetS risks with homeostasis model assessment of insulin resistance (HOMA-IR) were analyzed. HOMA-IR, number of risks, habits of smoking, exercise and drinking alcohol, stratified by HDL-C levels, were compared in MetS subjects. RESULTS: In cases with ≤2 risk factors, the higher the HDL-C, the lower the HOMA-IR. However, with ≥3 risk factors for MetS, the HOMA-IR increased when HDL-C was ≥90 mg/dL. In MetS subjects, the rate of alcohol intake ≥75 g/day was high when HDL-C was ≥90 mg/dL. CONCLUSION: In MetS subjects with high HDL-C levels, insulin resistance was increased. Therefore, in persons with high HDL-C levels, it is important to monitor the amount of alcohol consumption and reduce alcohol consumption to <75 g/day.

Optimal reference interval for homeostasis model assessment of insulin resistance in a Japanese population.

The aim of the present study was to establish a reference interval for homeostasis model assessment of insulin resistance (HOMA-IR) in a Japanese population based on the C28-A3 document from the Clinical and Laboratory Standards Institute (CLSI). We selected healthy subjects aged 20-79 years, with fasting plasma glucose < 100 mg/dL, body mass index < 25 kg/m(2) and alanine aminotransferase < 31 U/L. HOMA-IR values were log transformed, values beyond mean ± 3 standard deviations (SD) were truncated, and the mean ± 2 SD of log HOMA-IR values were taken as the upper and lower reference limits of HOMA-IR. We selected 2173 subjects as reference individuals, and 2153 subjects were used for analysis. The reference interval for HOMA-IR was established as between 0.4 and 2.4. This represents the first reference interval study for HOMA-IR that applies the stringent CLSI C28-A3 document. HOMA-IR ≥ 2.5 should be considered a reasonable indicator of insulin resistance in Japanese. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00113.x, 2011).