Minako Wakasugi

A combination of healthy lifestyle factors is associated with a decreased incidence of chronic kidney disease: a population-based cohort study

A combination of healthy lifestyle factors is associated with lower risks of coronary heart disease, diabetes and stroke, but little is known about its association with chronic kidney disease (CKD). This study analyzed the effect of a combination of healthy lifestyle factors on the incidence of proteinuria among participants without CKD. Of the 7565 persons aged 40–79 years who participated in the Specific Health Checkups and Guidance System in Sado Island, Japan in 2008, 4902 participants (2015 males) without CKD were included. The healthy lifestyle score was calculated by summing the total number of lifestyle factors for which the participants were at low risk. Low risk was defined as (1) nonsmoker, (2) body mass index (BMI) <25 kg m−2, (3) moderate or less alcohol consumption, (4) regular exercise and (5) better eating patterns. Logistic analysis was used to examine the relationship between the baseline score in 2008 and the development of proteinuria in 2009. Proteinuria developed in 2.2% of participants (males, 3.2; females, 1.5%). Compared with participants with a healthy lifestyle score of 0 to 2, participants with a score of 5 had a lower risk (odds ratio: 0.39, 95% confidence interval: 0.16–0.94), independently of having diabetes, hypertension and hypercholesterolemia. Overall, 47% of the cases in this cohort could be attributed to lack of adherence to this low-risk pattern. These findings underscore the importance of a healthier lifestyle in preventing CKD.

High mortality rate of infectious diseases in dialysis patients: a comparison with the general population in Japan.

Infectious disease is the second leading cause of death among dialysis patients, and it is generally assumed that the mortality rate of infectious disease is considerably higher in dialysis patients than in the general population. There are no comprehensive studies on this issue and on the contribution of each category of infectious disease to excess mortality in dialysis patients in Japan. We used mortality data reported to the Japanese Society for Dialysis Therapy and national Vital Statistics data for 2008 and 2009. We calculated standardized mortality ratios and compared the mortality rates for each category of infectious disease. During the 2‐year study period, 274 683 and 10 435 deaths from infectious diseases were recorded in 126 million people and 273 237 dialysis patients, respectively. The standardized mortality ratio for all infectious diseases was 7.5 (95% confidence interval, 7.3–7.6) in dialysis patients with respect to the general population in Japan. The categories of infectious disease with a significantly higher standardized mortality ratio among the dialysis patients were sepsis, peritonitis, influenza, tuberculosis, and pneumonia and in that order. In particular, the mortality rate of sepsis contributed to 69.5% of the difference in infectious disease mortality between dialysis patients and the general population. This study underlines markedly increased mortality from infectious diseases, particularly from sepsis, in dialysis patients compared with the general population.

Cause-specific excess mortality among dialysis patients: comparison with the general population in Japan.

Despite significant therapeutic advances, mortality of dialysis patients remains unacceptably high. The aim of this study is to compare mortality and its causes in dialysis patients with those in the general Japanese population. We used data for 2008 and 2009 from the Japanese Society for Dialysis Therapy registry and a national Vital Statistics survey. Cardiovascular mortality was defined as death attributed to heart failure, cerebrovascular disorders, myocardial infarction, hyperkalemia/sudden death, and pulmonary thromboembolism. Non‐cardiovascular mortality was defined as death attributed to infection, malignancies, cachexia/uremia, chronic hepatitis/cirrhosis, ileus, bleeding, suicide/refusal of treatment, and miscellaneous. We calculated standardized mortality ratios and age‐adjusted mortality differences between dialysis patients and the general population for all‐cause, cardiovascular versus non‐cardiovascular, and cause‐specific mortality. During the 2‐year study period, there were 2 284 272 and 51 432 deaths out of 126 million people and 273 237 dialysis patients, respectively. The standardized mortality ratio for all‐cause mortality was 4.6 (95% confidence interval, 4.6–4.7) for the dialysis patients compared to the general population. Age‐adjusted mortality differences for cardiovascular and non‐cardiovascular disease were 33.1 and 30.0 per 1000 person‐years, respectively. The standardized mortality rate ratios were significant for all cause‐specific mortality rates except accidental death. Our study revealed that excess mortality in dialysis patients compared to the general population in Japan is large, and differs according to age and cause of death. Cause‐specific mortality studies should be planned to improve life expectancies of dialysis patients.

Association between Combined Lifestyle Factors and Non-Restorative Sleep in Japan: A Cross-Sectional Study Based on a Japanese Health Database

Background Although lifestyle factors such as cigarette smoking, excessive drinking, obesity, low or no exercise, and unhealthy dietary habits have each been associated with inadequate sleep, little is known about their combined effect. The aim of this study was to quantify the overall impact of lifestyle-related factors on non-restorative sleep in the general Japanese population. Methods and Findings A cross-sectional study of 243,767 participants (men, 39.8%) was performed using the Specific Health Check and Guidance System in Japan. A healthy lifestyle score was calculated by adding up the number of low-risk lifestyle factors for each participant. Low risk was defined as (1) not smoking, (2) body mass index<25 kg/m2, (3) moderate or less alcohol consumption, (4) regular exercise, and (5) better eating patterns. Logistic regression analysis was used to examine the relationship between the score and the prevalence of non-restorative sleep, which was determined from questionnaire responses. Among 97,062 men (mean age, 63.9 years) and 146,705 women (mean age, 63.7 years), 18,678 (19.2%) and 38,539 (26.3%) reported non-restorative sleep, respectively. The prevalence of non-restorative sleep decreased with age for both sexes. Compared to participants with a healthy lifestyle score of 5 (most healthy), those with a score of 0 (least healthy) had a higher prevalence of non-restorative sleep (odds ratio, 1.59 [95% confidence interval, 1.29–1.97] for men and 2.88 [1.74–4.76] for women), independently of hypertension, hypercholesterolemia, diabetes, and chronic kidney disease. The main limitation of the study was the cross-sectional design, which limited causal inferences for the identified associations. Conclusions A combination of several unhealthy lifestyle factors was associated with non-restorative sleep among the general Japanese population. Further studies are needed to establish whether general lifestyle modification improves restorative sleep.

Mortality trends among Japanese dialysis patients, 1988–2013: a joinpoint regression analysis

BACKGROUND Evaluation of mortality trends in dialysis patients is important for improving their prognoses. The present study aimed to examine temporal trends in deaths (all-cause, cardiovascular, noncardiovascular and the five leading causes) among Japanese dialysis patients. METHODS Mortality data were extracted from the Japanese Society of Dialysis Therapy registry. Age-standardized mortality rates were calculated by direct standardization against the 2013 dialysis population. The average annual percentage of change (APC) and the corresponding 95% confidence interval (CI) were computed for trends using joinpoint regression analysis. RESULTS A total of 469 324 deaths occurred, of which 25.9% were from cardiac failure, 17.5% from infectious disease, 10.2% from cerebrovascular disorders, 8.6% from malignant tumors and 5.6% from cardiac infarction. The joinpoint trend for all-cause mortality decreased significantly, by -3.7% (95% CI -4.2 to -3.2) per year from 1988 through 2000, then decreased more gradually, by -1.4% (95% CI -1.7 to -1.2) per year during 2000-13. The improved mortality rates were mainly due to decreased deaths from cardiovascular disease, with mortality rates due to noncardiovascular disease outnumbering those of cardiovascular disease in the last decade. Among the top five causes of death, cardiac failure has shown a marked decrease in mortality rate. However, the rates due to infectious disease have remained stable during the study period [APC 0.1 (95% CI -0.2-0.3)]. CONCLUSIONS Significant progress has been made, particularly with regard to the decrease in age-standardized mortality rates. The risk of cardiovascular death has decreased, while the risk of death from infection has remained unchanged for 25 years.

Regional variation in hip fracture incidence among Japanese hemodialysis patients.

Hip fracture incidence in Japanese hemodialysis patients is five‐fold higher than in the general population, although the mechanisms underlying this difference are not fully understood. Substantial regional variation exists in hip fracture incidence in the general Japanese population, despite a uniform health care and insurance system and lack of ethnic and racial variation. In this study, we determined whether the regional variation seen in the general population also applies to hemodialysis patients in Japan. Standardized incidence ratios were calculated for each regional district, and regional variations of hip fracture incidence among hemodialysis patients were evaluated using data obtained from the Japanese Society for Dialysis Therapy registry (data collected from December 2007 to December 2008). Standardized hip fracture incidence ratios across the districts ranged from 0.71 to 1.29 for male and 0.49 to 1.36 for female hemodialysis patients. Incidence ratios tended to be higher in western Japan and lower in eastern Japan, suggesting that regional variation also exists among hemodialysis patients. Our findings suggest that common risk factors for hip fracture may be shared among the general population and hemodialysis patients. Further research aimed at identifying factors, including those associated with regional variation, may help decrease hip fracture incidence in both the general population and hemodialysis patients in Japan.

Association between Overall Lifestyle Changes and the Incidence of Proteinuria: A Population-based, Cohort Study

Objective This study aimed to examine the association between the changes in an overall healthy lifestyle, as quantified by the number of unhealthy lifestyle factors and obesity status, and the incidence of proteinuria in the general Japanese population. Methods A retrospective cohort study was conducted among 99,404 (men, 36.9%) participants aged from 40-74 years of age who underwent two health check-ups with a 1-year interval in Japan between 2008 and 2009. Any participants with chronic kidney disease at baseline were excluded. The smoking status, body mass index, physical activity, alcohol consumption, and healthy eating habits were combined into a simple overall healthy lifestyle score ranging from 0 to 5. The changes in overall healthy lifestyle scores from baseline (range, -5 to +5) and the incidence of proteinuria, defined by a dipstick urinalysis (score ≥1+), were assessed at the second check-up. A logistic regression analysis was used to examine the association between the changes in overall healthy lifestyle scores and the incidence of proteinuria. Results After one year of follow-up, 3.9% of men and 2.4% of women developed proteinuria. Each increase (or decrease) in the changes in overall healthy lifestyle scores was associated with a reduced (or increased) risk of proteinuria in both men (odds ratio (OR) 0.87; 95% confidence interval (CI), 0.81-0.94) and women (OR 0.87; 95%CI, 0.80-0.94) after adjusting for age, baseline lifestyle scores, hypertension, diabetes mellitus, and hypercholesterolemia. Stratified analyses based on age, the presence or absence of hypertension, or diabetes mellitus revealed similar results. Conclusion Overall lifestyle changes, even within a year, were found to influence the incidence of proteinuria.

Modifiable Factors Associated with Cognitive Impairment in 1,143 Japanese Outpatients: The Project in Sado for Total Health (PROST)

Background/Aims: Evidence on modifiable factors associated with cognitive impairment in Japanese patients is scarce. This study aimed to determine modifiable factors for cognitive impairment in a Japanese hospital-based population. Methods: Subjects of this cross-sectional study were 1,143 patients of Sado General Hospital (Niigata, Japan) registered in the Project in Sado for Total Health (PROST) between June 2008 and September 2014. We assessed disease history, body mass index (BMI), leisure time physical activity, walking time, smoking and drinking habits, and consumption of vegetables, fruits, and green tea as predictors, with cognitive impairment defined by the Mini-Mental State Examination (score <24) as an outcome. Multiple logistic regression analysis was performed to calculate odds ratios (ORs) for cognitive impairment. Results: The mean subject age was 68.9 years, and the prevalence of cognitive impairment was 21.5%. Multivariate analysis revealed that age (p < 0.001), low BMI (<21.1; OR 1.39, 95% CI 1.12-1.72), a history of stroke (p = 0.003), a history of myocardial infarction (p = 0.038), low fruit consumption (p for trend = 0.012), and low green tea consumption (p for trend = 0.032) were independently associated with a higher prevalence of cognitive impairment. Conclusions: Modifiable factors, such as low BMI, low fruit consumption, and low green tea consumption, are associated with cognitive impairment. Longitudinal studies will be needed to confirm these findings.

Association between Hypouricemia and Reduced Kidney Function: A Cross-Sectional Population-Based Study in Japan

Background: Hypouricemia, conventionally defined as a serum uric acid level of ≤2 mg/dl, is considered a biochemical disorder with no clinical significance. However, individuals with renal hypouricemia have a high risk of urolithiasis and exercise-induced acute kidney injury, both of which are risk factors for reduced kidney function. Methods: To test the hypothesis that individuals with hypouricemia would be at a higher risk of reduced kidney function, we conducted a population-based cross-sectional study using data from the Specific Health Checkups and Guidance System in Japan. Logistic analysis was used to examine the relationship between hypouricemia and reduced kidney function, defined as estimated glomerular filtration rate <60 ml/min/1.73 m2. Results: Among 90,710 men (mean age, 63.8 years) and 136,935 women (63.7 years), 193 (0.2%) and 540 (0.4%) were identified as having hypouricemia, respectively. The prevalence of hypouricemia decreased with age in women (p for trend <0.001), but not in men (p for trend = 0.24). Hypouricemia was associated with reduced kidney function in men (odds ratio, 1.83; 95% confidence interval, 1.23-2.74), but not in women (0.61; 0.43-0.86), relative to the reference category (i.e., serum uric acid levels of 4.1-5.0 mg/dl) after adjusting for age, drinking, smoking, diabetes, hypertension, hypercholesterolemia, obesity, and history of renal failure. Sensitivity analyses stratified by diabetic status yielded similar results. Conclusions: This study is the first to provide evidence that hypouricemia is associated with reduced kidney function in men. Further research will be needed to determine the long-term prognosis of individuals with hypouricemia.

Associations between the Intake of Miso Soup and Japanese Pickles and the Estimated 24-hour Urinary Sodium Excretion: A Population-based Cross-sectional Study

OBJECTIVE In Japan, reducing the consumption of miso soup and Japanese pickles, both traditional Japanese dishes, is recommended in order to decrease dietary salt intake. With the Westernization of dietary habits, however, these dishes are now consumed less frequently, and thus a reduction in their effect on sodium intake is suspected. This study examined cross-sectional associations between the frequency of intake of miso soup and Japanese pickles and the estimated 24-hour urine sodium excretion using data obtained from health examination surveys conducted in 2013 in Sado City, Japan. METHODS The level of daily salt intake was estimated based on spot urine sodium and creatinine measurements. The frequency of intake of miso soup and Japanese pickles was determined using a self-reported questionnaire. Multiple linear regression models were used to assess associations. RESULTS Among a total of 8,821 participants (3,956 men; age range, 19-97 years), the mean daily salt intake was 9.4 g/day. The frequency of intake of miso soup and Japanese pickles increased with age and was associated with the level of daily salt intake (p for trend <0.0001). A linear regression model analysis adjusted for age, sex, body mass index, hypertension, diabetes, hypercholesterolemia and chronic kidney disease revealed that daily salt intake was associated with the frequency of intake of miso soup (p<0.0001) and Japanese pickles (p<0.0001) in all age groups, except those ≥ 80 years of age. CONCLUSION These findings suggest that reducing the consumption of miso soup and Japanese pickles may be an effective approach for decreasing the level of dietary salt intake in the general Japanese population, although not in octogenarians or nonagenarians.