Alteration of normal level of serum urate may contribute to decrease in estimated glomerular filtration rate decline in healthy Japanese men.

INTRODUCTION: Serum uric acid (SUA) levels have a linear relationship with the estimated glomerular filtration rate (eGFR). It is unclear whether further changes, subsequent to normal level of SUA can attenuate eGFR decline in a healthy population, so we aimed to determine the normal level of SUA that can contribute to preventing kidney dysfunction. METHODS: In this retrospective cohort study from Japan, annual health checkup data from 2009 to 2014 was collected. After propensity score matching (1:1), data from 2,634 individuals with basal SUA ≤7.0 mg/dL (normal; mean age, 39 y; mean eGFR, 80.8 mL/min/1.73 m2) and 1,642 individuals with basal SUA >7.0 mg/dL (elevated; mean age, 42 y; mean eGFR, 75.0 mL/min/1.73 m2) were collected to determine the relationship between followed-up SUA level and the rate of change in eGFR. RESULTS: In individuals with normal level SUA at baseline, the elevation of SUA (>7.0 mg/dL) accelerated eGFR decline compared to those with normal SUA levels at 5-year follow-up (-4.1 ± 9.6% vs -9.9 ± 9.0%, p < .0001). Digression of SUA level (≤7.0 mg/dL) reduced eGFR decline compared with persistent SUA level over 7.0 mg/dL (-1.5 ± 11.5% vs -7.0 ± 10.1, p < .0001). In multiple linear regression analysis, there was strong association between the rate of change in SUA and eGFR in individuals with basal SUA ≤7.0 and >7.0 mg/dL (standardized coefficient; -0.3348, p < .001 and -.2523, p < .001, respectively). CONCLUSION: Subsequent to normal level of SUA (under 7.0 mg/dL) may contribute to a decrease in eGFR decline in apparently healthy men.

Relationship between abdominal adiposity and incident chronic kidney disease in young- to middle-aged working men: a retrospective cohort study.

BACKGROUND: Obesity is a risk factor for the development of chronic kidney disease (CKD). However, it remains to be fully examined whether fatness is more useful in predicting incident CKD. We aimed this study to determine the association of body fat, body mass index and waist circumference (WC) with subsequent changes in estimated glomerular filtration rate (eGFR) and incident CKD in young- to middle-aged working men. METHODS: We analyzed data from annual health check-up in male workers aged from 20 to 60 years with basal eGFR of 60-90 mL/min/1.73 m2. Cut-off values of parameters and odds ratio (OR) for the incident CKD were calculated by receiver operator characteristics analysis andχ2 test, respectively. We also tested trends of changes in eGFR according to changes in WC in each age decade. RESULTS: There were 8,015 men participants. During the 5-year follow-up, 11.0% of the participants (N = 878) had developed to incident CKD. When basal WC was greater than 80.0 cm, which was decided by Youden's Index, there was a significantly higher risk of incident CKD [OR 1.57 (95% confident interval 1.35-1.84)]. Changes in WC over 5 years were significantly related to eGFR decline in young men (< 40 years old) with normal blood pressures and normoglycemia. CONCLUSIONS: These findings suggest that WC > 80.0 cm is a risk factor for incident CKD and strongly associated with a decline in eGFR in the young- to middle-aged working healthy men.

Impact of low-density lipoprotein cholesterol on decline in estimated glomerular filtration rate in apparently healthy young to middle-aged working men.

BACKGROUND: It remains to be fully clarified whether there is a relationship between uncontrolled dyslipidemia and decline in estimated glomerular filtration rate (eGFR) in the general population. Therefore, this study's aim was to test the association of dyslipidemia with changes in eGFR in apparently healthy working men. METHODS: We retrospectively examined the annual medical check-up list of 14,510 male workers aged 20-60 years with eGFR ≥ 60 mL/min/1.73 m2 at baseline, and then evaluated the association of the changes in the check-up parameters with a decline in eGFR during the 5-year observation period. RESULTS: Mean age and eGFR were 38.5 years and 82.3 mL/min/1.73 m2 at baseline, respectively. Evaluated low-density lipoprotein cholesterol (LDL-C) (≥140 mg/dL) was a strong indicator of CKD development in participants (basal eGFR 60-90 mL/min/1.73 m2) without hypertension [odds ratio (95% confidence interval): 1.46 (1.12-1.90)] or diabetes mellitus (DM) [1.49 (1.23-1.82)]. When LDL-C normalized under 140 mg/dL during follow-up, the decline in eGFR was smaller in non-hypertensive participants [-5.9 (-14.4 to -0.9) vs -13.4 (-18.4 to -4.5) mL/min/1.73 m2, p < 0.05]. There was an inverse correlation between change of LDL-C and decline in eGFR (p for trend <0.001). CONCLUSION: Increased LDL-C levels are associated with the development of incident CKD and eGFR decline in young to middle-aged working men without hypertension and/or DM.

Development of chronic kidney disease influenced by serum urate and body mass index based on young-to-middle-aged Japanese men: a propensity score-matched cohort study.

OBJECTIVE: To investigate the association between serum uric acid (SUA) level and body mass index (BMI) on the development of chronic kidney disease (CKD) in working men aged 20-60 years. DESIGN: Retrospective cohort study. SETTING: Data from employees' annual health check-ups were collected from two companies in 2009 and 2014. PARTICIPANTS: A total of 16 708 working men were recruited. We excluded participants with missing essential data (N=7801), who had basal estimated glomerular filtration rate (eGFR) <60.0 mL/min/1.73 m2 and/or proteinuria (N=698) or with the absence of follow-up data (N=2). PRIMARY OUTCOME: eGFR <60 mL/min/1.73 m2 and/or proteinuria (≥1+) in 2014 (defined as incident CKD). RESULTS: The cut-off values of SUA for incident CKD were 6.6 mg/dL in both young (20-39 years old) and middle-aged (40-60 years old) men analysed by receiver operator characteristics. ORs for incident CKD were assessed on propensity score-matched (1:1) cohorts. In young participants (N=1938), after propensity score matching, a coexistence of high-level SUA (≥6.6 mg/dL) and overweight (BMI ≥25 kg/m2) was a significant risk factor of incident CKD (OR=2.18, 95% CI 1.10 to 4.31, p=0.025), but high-level SUA was not an independent risk factor without overweight status (p=0.174). In middle-aged participants (N=2944) after propensity score matching, high-level SUA was a significant risk factor of incident CKD both with or without overweight (OR=1.44, 95% CI 1.02 to 2.04, p=0.037; OR=1.32, 95% CI 1.01 to 1.73, p=0.041, respectively). CONCLUSION: These findings suggest that high-level SUA is strongly associated with incident CKD in overweight young adult men.

Potential link between high FIB-4 score and chronic kidney disease in metabolically healthy men.

Although the association between non-alcoholic fatty liver disease and chronic kidney disease (CKD) has been well known, it is unclear whether Fibrosis-4 (FIB-4) score is a predictor of CKD development. We performed this retrospective cohort study, with a longitudinal analysis of 5-year follow-up data from Japanese annual health check-ups. Participants with CKD (estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73 m2 and/or proteinuria) and a habit of alcohol consumption were excluded. The cut-off FIB-4 score was 1.30, indicating increased risk of liver fibrosis. Overall, 5353 participants (men only) were analyzed without exclusion criteria. After propensity score matching, high FIB-4 score (≥ 1.30) was not an independent risk factor for incident CKD (odds ratio [OR] 1.57; 95% confidence interval [CI] 0.97-2.56). However, high FIB-4 score was a significant risk factor for CKD in non-obese (OR 1.92; 95% CI 1.09-3.40), non-hypertensive (OR 2.15; 95% CI 1.16-3.95), or non-smoking (OR 1.88; 95% CI 1.09-3.23) participants. In these participants, FIB-4 score was strongly associated with eGFR decline in the multiple linear regression analysis (ß = - 2.8950, P = 0.011). Therefore, a high FIB-4 score may be significantly associated with CKD incidence after 5 years in metabolically healthy participants.

Does sleep improve memory organization?

Sleep can integrate information into existing memory networks, look for common patterns and distil overarching rules, or simply stabilize and strengthen the memory exactly as it was learned. Recent research has shown that sleep facilitates abstraction of gist information as well as integration across multiple memories, insight into hidden solutions, and even the ability to make creative connections between distantly related ideas and concepts. To investigate the effect of sleep on memory organization, 35 normal volunteers were randomly assigned either to the sleep (n = 17) or wake group (n = 18). The sleep subjects performed the Japanese Verbal Learning Test (JVLT), a measure of learning and memory, three times in the evening, and slept. On the following morning (9 h later), they were asked to recall the words on the list. The wake subjects took the same test in the morning, and were asked to recall the words in the same time interval as in the sleep group. The semantic clustering ratio (SCR), divided by the total number of words recalled, was used as an index of memory organization. Our main interest was whether the sleep subjects elicit a greater increase in this measure from the third to the fourth assessments. Time × Group interaction effect on SCR was not significant between the sleep group and wake group as a whole. Meanwhile, the change in the SCR between the third and fourth trials was negatively correlated with duration of nocturnal waking in the sleep group, but not other sleep indices. Based on this observation, further analysis was conducted for subjects in the sleep group who awoke nocturnally for <60 min for comparison with the wake group. A significant Time × Group interaction was noted; these "good-sleepers" showed a significantly greater improvement in the memory index compared with the wake subjects. These results provide the first suggestion that sleep may enhance memory organization, which requires further study.