The role of cigarette smoking on new-onset of chronic kidney disease in a Japanese population without prior chronic kidney disease: Iki epidemiological study of atherosclerosis and chronic kidney disease (ISSA-CKD)

Cigarette smoking and progression of kidney dysfunction: a longitudinal cohort study

INTRODUCTION

Cigarette smoking is one of the most important life-modifiable risk factors for CVD events. The effect on CKD progression caused by smoking remained uncertain, while the effect on CVD had been established.

METHOD

The study population included participants from the specific health check and specific health guidance, an annual health check-up for all inhabitants of Japan who were aged between 40 and 74 years. 149,260 subjects (male, 37.1%; female, 62.9%) were included in this analysis.

RESULTS

The relationship between smoking status along with new-onset proteinuria and eGFR deterioration more than 15 mL/min/1.73 m2 was examined. Median observation periods were 1427 days [738, 1813] in males and 1437 days [729, 1816] in females. In male participants, the strongest factor upon kidney dysfunction was new-onset proteinuria (1.41 [1.31 1.51], P < 0.001). The second strongest factor on kidney deterioration was smoking (1.24 [1.16 1.31], P < 0.001). In female participants, strongest factor upon kidney dysfunction was smoking (1.27 [1.16-1.39], P < 0.001). The second strongest factor on kidney deterioration was new-onset proteinuria (1.26 [1.17 1.36], P < 0.001). To reveal the relationship of effects from new-onset proteinuria and smoking on the kidney function, the participants were divided into four groups with and without new-onset proteinuria and smoking. The group with both proteinuria and smoking had significantly worst renal prognosis (P for trend < 0.001).

CONCLUSION

Large longitudinal observation study revealed smoking has an evil effect on the progression of CKD. This evil effect could be observed in CKD patients with proteinuria as well as in general population without new-onset proteinuria.

Childhood modifiable risk factors and later life chronic kidney disease: a systematic review

BACKGROUND

Relationships between adulthood modifiable risk factors and chronic kidney disease (CKD) are well-established, but associations with childhood risk factors are unclear. This study systematically assesses the published evidence about childhood modifiable risk factors and adulthood CKD.

METHODS

We searched MEDLINE, EMBASE, and Web of Science to 6th May 2022. Articles were included if (1) they were population-based longitudinal studies, (2) exposures were potentially modifiable, for example through pharmacological or lifestyle modifications, including clinical conditions/measures (diabetes, blood pressure, adiposity, and dyslipidaemia); health behaviours (smoking, alcohol consumption, physical activity, fitness, and poor nutrition); and socio-economic factors (socio-economic position), and occurred during childhood (ages 2-19 years), and (3) outcome was CKD or surrogate markers of CKD in adulthood (ages 20 years or older). Three reviewers independently extracted the data.

RESULTS

15,232 articles were identified after deduplication; 17 articles met the inclusion criteria, reporting childhood blood pressure (n = 8), adiposity (n = 4), type 2 diabetes (n = 1), socio-economic position (n = 1), famine (n = 1), cardiorespiratory fitness (n = 1), and a healthy lifestyle score (n = 1). The results suggested positive associations of childhood adiposity, type 2 diabetes, and low socio-economic position and cardiorespiratory fitness in females with CKD in adulthood. Findings were inconsistent on associations between childhood BP and CKD in adulthood. Childhood healthy lifestyle score and exposure to famine were not associated with risk of CKD in adulthood.

CONCLUSIONS

The limited evidence suggests childhood factors may contribute to the CKD risk in adulthood, particularly adiposity, type 2 diabetes, and low socio-economic position and cardiorespiratory fitness in females. Further high-quality community-based studies are needed with long-term follow-up and investigation of a broader range of modifiable risk factors.

Serum triglyceride levels and incidence of hypertension in a general Japanese population: ISSA-CKD study

The aim of this study was to clarify the relationship between fasting and nonfasting serum triglyceride (TG) levels and the incidence of hypertension in a general Japanese population. We conducted a population-based retrospective cohort study using annual health check-up data of residents of Iki City, Nagasaki Prefecture, Japan. A total of 3202 participants without hypertension at baseline were included in the present analysis. TG levels were classified as quartile 1 (<0.82 mmol/L), quartile 2 (0.83-1.13 mmol/L), quartile 3 (1.14-1.70 mmol/L) and quartile 4 (≥1.71 mmol/L) for men, and as quartile 1 (<0.70 mmol/L), quartile 2 (0.71-0.96 mmol/L), quartile 3 (0.97-1.34 mmol/L) and quartile 4 (≥1.35 mmol/L) for women. The outcome was incident hypertension. During an average follow-up of 4.4 years, 983 participants developed hypertension, according to the Cox proportional hazards model. The annual incidence of hypertension increased with an elevation in TG levels for men (5.88% in quartile 1, 8.30% in quartile 2, 7.62% in quartile 3, and 9.82% in quartile 4). This association was significant, even after adjustment for other risk factors: hazard ratio 1.41 [95% CI 1.07-1.85] for quartile 2, 1.30 [0.99-1.71] for quartile 3, and 1.59 [1.22-2.08] for quartile 4 compared with quartile 1 (p = 0.041 for trend). In contrast, there was no clear association between serum TG levels and the incidence of hypertension after adjustment for confounding factors among women (p = 0.240 for trend). High levels of serum TG were associated with the future incidence of hypertension in a general population of Japanese men but were not associated with that in women. Casual serum triglyceride levels and incidence of hypertension in a general Japanese population: ISSA-CKD study.

The effect of the Kasuya CKD network on prevention of the progression of chronic kidney disease: successful collaboration of a public health service, primary care physicians and nephrologists-community based cohort study

BACKGROUND

In 2012, we established a CKD network in collaboration with the public health service, primary care physicians, and nephrologists in the Kasuya area. The aim of this study was to clarify if our CKD network was effective in preventing CKD progression.

METHODS

1591 subjects, who had CKD in health checks in 2012 were included in this study. The slope of estimated glomerular filtration rate (eGFR) was compared before and after 2012. Parameters at the first health check visit before 2012, visit in 2012, and the last visit after 2012, were compared. Paired t test, analysis of variance for repeated measurements, and the Friedman test were used for the analysis.

RESULTS

Mean age was 65 years. There were 781 men and 810 women. Mean eGFR was 59 ml/min/1.73 m². The mean slope of eGFR before 2012 was -1.833 ml/min/1.73 m²/year and significantly reduced to - 0.297 after 2012. Low-density lipoprotein cholesterol showed a significant serial lowering. Uric acid was significantly elevated in 2012 compared to the first visit and had decreased by the last. The dipstick urinary protein significantly increased in 2012 compared to the first visit and decreased by the last. The number of current smokers showed a significant reduction over time. On the other hand, systolic blood pressure (SBP) and HbA1c significantly elevated at the last visit.

CONCLUSION

The Kasuya CKD network may be effective in preventing CKD progression.

The Lifelong Health Support 10: a Japanese prescription for a long and healthy life

Background

Although the age-adjusted incidence and mortality of cancer and cardiovascular disease (CVD) have been decreasing steadily in Japan, both diseases remain major contributors to morbidity and mortality along with the aging society. Herein, we aim to provide a prescription of 10 health tips for long and healthy life named the “Lifelong Health Support 10 (LHS10).”

Method

The LHS10 was developed by the preventive medicine specialists at the National Cerebral and Cardiovascular Center in Suita, where it has been used for health guidance to prevent CVD, cancer, and cognitive decline in addition to their major risk factors such as hypertension, diabetes, and obesity. It consisted of the lifestyle modification recommendations of the 2014 Japanese Society of Hypertension guidelines and the 2017 Japan Atherosclerosis Society Guidelines for preventing atherosclerotic CVD. Further, it came in line with other international lifestyle modification guidelines. In this narrative review, we summarized the results of several Japanese epidemiological studies investigating the association between the LHS10 items and the risk of cancer, CVD, and other chronic diseases including dementia, diabetes, and chronic kidney disease.

Results

The LHS10 included avoiding smoking and secondhand smoke exposure, engaging in physical activity, refraining from excessive alcohol drinking, reducing fried foods and sugary soft drinks, cutting salt in food, consuming more vegetables, fruits, fish, soy foods, and fibers, and maintaining proper body weight. All items of the LHS10 were shown to reduce the risk of cancer, CVD, and other chronic diseases.

Conclusions

The LHS10 can be a helpful tool for health guidance.

Supplementary information

The online version contains supplementary material available at https://doi.org/10.1265/ehpm.22-00085.

Effect of chronic kidney disease on the association between hyperuricemia and new-onset hypertension in the general Japanese population: ISSA-CKD study

We aimed to investigate the association between serum uric acid (SUA) level and development of hypertension as well as the interaction effect of chronic kidney disease (CKD) on this relationship in the general Japanese population. We included 7895 participants aged ≥30 years from the ISSA‐CKD study, a population‐based retrospective cohort study that used annual health check‐up data of residents from Iki Island, Japan. After the exclusion of 1881 with l < 1‐year follow‐up, 2812 with hypertension at baseline, and 165 with missing information on SUA, a total of 3037 participants were enrolled in this analysis. Participants were divided into four groups according to the quartiles of SUA level at baseline, and multivariable‐adjusted hazard ratios for new‐onset hypertension were calculated. Stratified analyses were performed for each subgroup (defined by sex, age, alcohol intake, and CKD) to assess the interaction effects. During a mean follow‐up period of 4.4 years, 943 participants developed hypertension. The first quartile group was set as the reference group, and the multivariable‐adjusted hazard ratios (95% confidence interval) for new‐onset hypertension were 1.11 (0.90–1.36) in the second quartile, 1.25 (1.02–1.54) in the third quartile, and 1.35 (1.07–1.70) in the fourth quartile compared with those in the reference group (p = .007 for trend). The stratified analyses showed that the association between SUA and hypertension was significantly stronger in participants with CKD than in those without CKD (p = .035 for interaction). SUA level is an independent risk factor for new‐onset hypertension. This tendency was significantly stronger in participants with CKD.

Lifestyle interventions for preventing and ameliorating CKD in primary and secondary care

PURPOSE OF REVIEW

Despite the growth in chronic kidney disease (CKD) epidemics, evidence-based lifestyle recommendations for primary prevention of CKD are limited by reliance on observational studies and predominantly pilot clinical trials.

RECENT FINDINGS

Emerging data have shown lifestyle modification strategies for primary CKD prevention with the most evidence favoring a healthy dietary pattern (rich in fruit, vegetables, potassium and have a higher plant-based to animal protein ratio), and diet low in sodium, being physically active, avoiding tobacco smoking, moderating alcohol consumption and maintaining a healthy body weight. The way these behavioral interventions can be implemented in practice should consider their synergistic benefit as well as mechanisms to facilitate long-term behavior change. Sustaining long-term behavior change remains a challenge in practice, particularly due to a lack of healthcare resources and behavior relapse. Some suggestions to mitigate this include ensuring adequate time is spent in intervention codesign and planning, utilizing adaptive trial/intervention designs with regular intervention tailoring for intervention dose, intensity, duration, and modality.

SUMMARY

A number of modifiable lifestyle behaviors consistently associate with developing CKD in the community. The current evidence base, despite its inherent limitations, may inform both public health recommendations and clinical practice.

Emerging role of air pollution in chronic kidney disease

Chronic kidney disease (CKD), a global disease burden related to high rates of incidence and mortality, manifests as progressive and irretrievable nephron loss and decreased kidney regeneration capacity. Emerging studies have suggested that exposure to air pollution is closely relevant to increased risk of CKD, CKD progression and end-stage kidney disease (ESKD). Inhaled airborne particles may cause vascular injury, intraglomerular hypertension, or glomerulosclerosis through non-hemodynamic and hemodynamic factors with multiple complex interactions. The mechanisms linking air pollutants exposure to CKD include elevated blood pressure, worsening oxidative stress and inflammatory response, DNA damage and abnormal metabolic changes to aggravate kidney damage. In the present review, we will discuss the epidemiologic observations linking air pollutants exposure to the incidence and progression of CKD. Then, we elaborate the potential roles of several air pollutants including particulate matter and gaseous co-pollutants, environmental tobacco smoke, and gaseous heavy metals in its pathogenesis. Finally, this review outlines the latent effect of air pollution in ESKD patients undergoing dialysis or renal transplant, kidney cancer and other kidney diseases. The information obtained may be beneficial for further elucidating the pathogenesis of CKD and making proper preventive strategies for this disease.

Metabolic associated fatty liver disease is a risk factor for chronic kidney disease

Background and Aims

To clarify the relationship between metabolic dysfunction‐associated fatty liver disease (MAFLD) and chronic kidney disease (CKD).

Methods

The participants were divided into four groups by the presence or absence of fatty liver disease (FLD) and metabolic dysfunction (MD). MAFLD was defined as having both FLD and MD, whereas CKD was defined as having an estimated glomerular filtration rate of <60 mL/min/1.73 m² and/or proteinuria.

Results

In this cross‐sectional study of 27,371 participants, the proportions of those in the non‐FLD without MD, non‐FLD with MD, FLD without MD, and MAFLD groups were 48.7, 28.2, 2.3, and 20.8%, respectively. Compared with non‐FLD without MD, MAFLD was associated with the risk of CKD (adjusted odds ratio 1.83 [1.66–2.01], P < 0.001), whereas FLD without MD was not (1.02 [0.79–1.33], P = 0.868). Moreover, compared with FLD without MD, MAFLD was associated with the risk of CKD (1.19 [1.09–1.31], P < 0.001). In this retrospective cohort study, 16,938 of 27,371 participants underwent a median 4.6 (2.0–8.1) years follow‐up, and incident data of non‐FLD without MD, non‐FLD with MD, FLD without MD, and MAFLD were 21.0, 31.1, 26.1, and 31.1 cases per 1,000 person‐years, respectively. Compared with the non‐FLD without MD, MAFLD was associated with the risk of incident CKD (adjusted hazard ratio 1.24 [1.14–1.36], P < 0.001), whereas FLD without MD was not (1.11 [0.85–1.41], P = 0.433).

Conclusions

MAFLD was associated with a risk of CKD, whereas FLD without MD was not a risk for CKD.

Eating before bed and new-onset hypertension in a Japanese population: the Iki city epidemiological study of atherosclerosis and chronic kidney disease

The aim of this study was to determine the relationship between eating before bed and the development of hypertension in a general Japanese population. We conducted a population-based retrospective cohort study using annual health check-up data collected from the residents of Iki City, Nagasaki Prefecture, Japan. In total, 2930 participants without hypertension at baseline (mean age 57.0 years, male 42.8%) were included in the present analysis. Eating before bed was defined as eating within 2 h of bedtime. The outcome of this study was incident hypertension (blood pressure ≥140/90 mmHg or initiation of blood pressure-lowering medications). Multivariable-adjusted hazard ratios and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models. During an average follow-up of 4.5 years, 909 participants developed hypertension. The incidence (per 1000 person-years) of hypertension in the group of individuals who ate before bed was 82.8, whereas that in the group of individuals who did not eat before bed was 65.8. The association was significant even after adjusting for other risk factors, including age, sex, current smoking status, current alcohol intake, regular exercise, obesity, elevated blood pressure, diabetes mellitus, and dyslipidemia, with a hazard ratio of 1.23 (95% CI: 1.05-1.44) for the group of individuals who ate before bed compared with the group of individuals who did not eat before bed (P = 0.01 for trend). Eating before bed was correlated with a future risk of developing hypertension in the general Japanese population.

Effects of Weight Gain after 20 Years of Age and Incidence of Hyper-Low-Density Lipoprotein Cholesterolemia: The Iki Epidemiological Study of Atherosclerosis and Chronic Kidney Disease (ISSA-CKD)

The aim of this study was to investigate the effects of long-term weight gain from the age of 20 on incidence of hyper-low-density-lipoprotein (LDL) cholesterolemia in the general population of Japanese people. Methods: We conducted a population-based retrospective cohort study using annual health checkup data for residents of Iki City, Nagasaki Prefecture, Japan. A total of 3179 adult (≥30 years old) men and women without hyper-LDL cholesterolemia at baseline, who underwent two or more health checkups were included in the analysis. Information on weight gain (≥10 kg) after 20 years of age was obtained using questionnaire. The outcome of this study was development of hyper-LDL cholesterolemia defined as LDL-cholesterol level ≥3.62 mmol/L and/or initiation of lipid-lowering medications. Results: During a mean follow-up period of 4.53 years, 665 of the 3179 participants developed hyper-LDL cholesterolemia (46.5/1000 person-years). The incidence of hyper-LDL cholesterolemia was higher in participants with a weight gain of ≥10 kg (55.3/1000 person-years) than among those with a weight gain of <10 kg (41.8/1000 person-years). This association remained statistically significant even after adjustment for age, sex, smoking, daily drinking, exercise, obesity, hypertension, and diabetes (multivariable hazard ratio 1.31, 95% confidence interval 1.08–1.58, p = 0.006). Conclusion: A weight gain of ≥10 after 20 years of age affected the development of hyper-LDL cholesterol regardless of age, sex, and obesity in a general population of Japanese.

The distribution of eGFR by age in a community-based healthy population: the Japan specific health checkups study (J-SHC study)

BACKGROUND

Renal function gradually declines with age. However, the association between changes in renal function and healthy aging has not been determined. This study examined the distribution of estimated glomerular filtration rate (eGFR) values in healthy subjects by age using large-scale cross-sectional data of health check-up participants in Japan.

METHODS

Among the 394,180 health check-up participants, 75,217 (19.1%) subjects without hypertension, diabetes, hyperlipidemia, obesity, proteinuria, smoking, past history of cardiovascular diseases, and renal failure/not undergoing dialysis were included in the healthy group. The distribution of eGFR values was determined at each age between 39 and 74 years.

RESULTS

in healthy subjects, the mean (± 2 SD range) values of eGFR (mL/min/1.73 m²) at ages 40, 50, 60, and 70 were 88.0 (55.4-121.7), 82.3 (51.2-113.3), 77.8 (48.1-107.6), and 72.9 (44.7-101.1), respectively. The difference in the mean eGFR by age was almost constant across all ages. In the linear regression analysis adjusted for sex, the regression coefficient of mean eGFR for a one-year increase in age was -0.46 mL/min/1.73 m² in healthy subjects (P < 0.001). By sex, the distribution of eGFR and the 1-year change in eGFR showed similar results in both men and women.

CONCLUSIONS

Renal function slowly declined with age in a healthy population; however, it was relatively preserved until the mid 70 s. This result suggests that a decline in renal function often observed in the elderly does not attribute to aging alone, and further examination might be required to clarify the cause of renal impairment.

Curcumin as a Natural Remedy for Atherosclerosis: A Pharmacological Review

Curcumin, a natural polyphenolic compound present in Curcuma longa L. rhizomes, shows potent antioxidant, anti-inflammatory, anti-cancer, and anti-atherosclerotic properties. Atherosclerosis is a comprehensive term for a series of degenerative and hyperplasic lesions such as thickening or sclerosis in large- and medium-sized arteries, causing decreased vascular-wall elasticity and lumen diameter. Atherosclerotic cerebro-cardiovascular disease has become a major concern for human health in recent years due to its clinical sequalae of strokes and heart attacks. Curcumin concoction treatment modulates several important signaling pathways related to cellular migration, proliferation, cholesterol homeostasis, inflammation, and gene transcription, among other relevant actions. Here, we provide an overview of curcumin in atherosclerosis prevention and disclose the underlying mechanisms of action of its anti-atherosclerotic effects.

Eating Speed and Incidence of Diabetes in a Japanese General Population: ISSA-CKD

Background: We investigated whether eating speed was associated with the incidence of diabetes in a Japanese general population. Methods: A total of 4853 Japanese individuals without diabetes at baseline were analyzed. Self-reported eating speed was categorized as slow, medium, and fast on the basis of questionnaire responses. The study outcome was the incidence of diabetes. Results: After an average follow-up period of 5.1 years, 234 individuals developed diabetes. The incidence of diabetes per 1000 person-years was 4.9 in the slow eating speed group, 8.8 in the medium eating speed group, and 12.5 in the fast eating speed group, respectively (*** p < 0.001 for trend). The HRs were 1.69 (95%CI 0.94–3.06) for the medium eating speed and 2.08 (95%CI 1.13–3.84) for the fast eating speed, compared to the slow eating speed (* p = 0.014 for trend) after adjustment for age, gender, smoking status, drinking, exercise, obesity, hypertension, and dyslipidemia. Conclusion: Faster eating speed increased a risk for the incidence of diabetes in a general Japanese population.

Frequency of Breakfast, Lunch, and Dinner and Incidence of Proteinuria: A Retrospective Cohort Study

Although multiple studies have revealed a close association of skipping breakfast with cardiometabolic diseases, few studies have reported its association with chronic kidney disease (CKD). Furthermore, there is scant reporting on the clinical impacts that skipping lunch and dinner has on cardiometabolic diseases and CKD. This retrospective cohort study, including 5439 female and 4674 male workers of a national university in Japan who underwent annual health checkups between January 2005 and March 2013, aimed to assess an association of frequencies of breakfast, lunch, and dinner with incidence of proteinuria (dipstick urinary protein ≥1+). The incidence of proteinuria was observed in 763 (14.0%) females and 617 (13.2%) males during the median 4.3 and 5.9 years of the observational period, respectively. In females, skipping breakfast as well as skipping dinner, but not lunch, were associated with the incidence of proteinuria (adjusted hazard ratios of breakfast frequency of "every day", "sometimes", and "rarely": 1.00 (reference), 1.35 (1.09-1.66), and 1.54 (1.22-1.94), respectively; those of dinner frequency of "every day" and "≤sometimes": 1.00 (reference) and 1.31 (1.00-1.72), respectively). However, no association was observed in male workers. Skipping breakfast and skipping dinner were identified as risk factors of proteinuria in females, but not in males.