C-reactive protein is associated with cigarette smoking-induced hyperfiltration and proteinuria in an apparently healthy population

Anti-atherogenic role of green tea (Camellia sinensis) in South Indian smokers

ETHNOPHARMACOLOGICAL RELEVANCE

Green tea (Camellia sinensis) is a popular beverage consumed all over the world due to its health benefits. Many of these beneficial effects of green tea are attributed to polyphenols, particularly catechins.

AIM OF THE STUDY

The present study focuses on underlying anti-platelet aggregation, anti-thrombotic, and anti-lipidemic molecular mechanisms of green tea in South Indian smokers.

MATERIALS AND METHODS

We selected 120 South Indian male volunteers for this study to collect the blood and categorised them into four groups; control group individuals (Controls), smokers, healthy control individuals consuming green tea, and smokers consuming green tea. Smokers group subjects have been smoking an average 16-18 cigarettes per day for the last 7 years or more. The subjects (green tea consumed groups) consumed 100 mL of green tea each time, thrice a day for a one-year period.

RESULTS

LC-MS analysis revealed the presence of multiple phytocompounds along with catechins in green tea extract. Increased plasma lipid peroxidation (LPO), protein carbonyls, cholesterol, triglycerides, and LDL-cholesterol with decreased HDL-cholesterol levels were observed in smokers compared to the control group and the consumption of green tea showed beneficial effect. Furthermore, docking studies revealed that natural compounds of green tea had high binding capacity with 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA) when compared to their positive controls, whereas (-) epigallocatechin-3-gallate (EGCG) and (-) epicatechin-gallate (ECG) had high binding capacity with sterol regulatory element-binding transcription factor 1 (SREBP1c). Further, our ex vivo studies showed that green tea extract (GTE) significantly inhibited platelet aggregation and increased thrombolytic activity in a dose dependent manner.

CONCLUSION

In conclusion, in smokers, catechins synergistically lowered oxidative stress, platelet aggregation and modified the aberrant lipid profile. Furthermore, molecular docking studies supported green tea catechins' antihyperlipidemic efficacy through strong inhibitory activity on HMG-CoA reductase and SREBP1c. The mitigating effects of green tea on cardiovascular disease risk factors in smokers that have been reported can be attributed majorly to catechins or to their synergistic effects.

Renal Hyperfiltration as a New Mechanism of Smoking-Related Mortality

INTRODUCTION

Renal hyperfiltration (RHF), an established risk factor for mortality, is prevalent among tobacco smokers. The aim of this study was to assess the mediating role of RHF in the association between smoking and mortality.

AIMS AND METHODS

Data of this study were retrieved from the cohort of the Kuopio Ischemic Heart Disease Risk Factor Study (KIHD), including 2064 males from Finland. Study participants were followed over a 35-year period. Using classic and counterfactual mediation analysis approaches, we estimated the mediative effect of RHF in the association between smoking and each of the following outcomes: All-cause mortality, cardiovascular disease (CVD) mortality, and non-CVD mortality.

RESULTS

The risk of all-cause mortality in smokers was twice that in nonsmokers (hazard ratio [HR], 2.06; 95% confidence interval [CI]: 1.84 to 2.31). Under the counterfactual framework the direct effect of smoking on all-cause mortality, controlled for RHF, corresponded to an HR of 2.00 (95% CI: 1.78 to 2.30). Of the effect of smoking on mortality, 5% (p-value = .016) was mediated by RHF. This finding concerned particularly non-CVD mortality.

CONCLUSIONS

RHF mediated the effect of smoking on non-CVD and all-cause mortality, but not on CVD mortality. The generalizability of our study results is however limited by its focus on a Finnish male cohort, underscoring the need for further investigation into RHF's broader implications across diverse populations.

IMPLICATIONS

This study elucidates the complex interplay between smoking, renal hyperfiltration (RHF), and mortality, offering novel insights into the mediating role of RHF. Our findings demonstrate that RHF significantly mediates the relationship between smoking and non-cardiovascular disease (non-CVD), but not CVD mortality. This distinction underscores the multifaceted role of RHF beyond its established association with cardiovascular events. By highlighting the specific pathways through which RHF mediates some of the smoking-attributed mortality, this research contributes to our understanding of the mechanisms linking smoking to mortality.

Inflammation and renal function decline in chronic coronary syndrome: a prospective multicenter cohort study

BACKGROUND

Renal function decline is a frequently encountered complication in patients with chronic coronary syndrome. Aside from traditional cardiovascular risk factors, the inflammatory burden emerged as the novel phenotype that compromised renal prognosis in such population.

METHODS

A cohort with chronic coronary syndrome was enrolled to investigate the association between inflammatory status and renal dysfunction. Levels of inflammatory markers, including high-sensitivity C-reactive protein (hs-CRP), tumour necrosis factor-α (TNF-α), adiponectin, matrix metalloproteinase-9, interleukin-6, lipoprotein-associated phospholipase A2, were assessed. Renal event was defined as > 25% decline in estimated glomerular filtration rate (eGFR). Inflammatory scores were calculated based on the aggregate of hs-CRP, TNF-α, and adiponectin levels.

RESULTS

Among the 850 enrolled subjects, 145 patients sustained a renal event during an averaged 3.5 years follow-up. Multivariate analysis with Cox regression suggested elevations in hs-CRP, TNF-α, and adiponectin levels were independent risk factors for the occurrence of a renal event. Whereas, Kaplan-Meier curve illustrated significant correlation between high TNF-α (P = 0.005), adiponectin (P < 0.001), but not hs-CRP (P = 0.092), and eGFR decline. The aggregative effect of these biomarkers was also distinctly correlated with renal events (score 2: P = 0.042; score 3: P < 0.001).

CONCLUSIONS

Inflammatory burden was associated with eGFR decline in patients with chronic coronary syndrome.

Effects of Smoking on Diabetic Nephropathy

Diabetes is a systemic metabolic disease with serious complications that cause significant stress on the healthcare system. Diabetic kidney disease is the primary cause of end stage renal disease globally and its progression is accelerated by various factors. Another major healthcare hazard is tobacco consumption and smoking has deleterious effects on renal physiology. Prominent factors are defined as sympathetic activity, atherosclerosis, oxidative stress and dyslipidemia. This review aims to enlighten the mechanism underlying the cumulative negative effect of simultaneous exposure to hyperglycemia and nicotine.

Association of Single Measurement of dipstick proteinuria with physical performance of military males: the CHIEF study

BACKGROUND

Proteinuria, a marker of kidney injury, may be related to skeletal muscle loss. Whether the severity of proteinuria is associated with physical performance is unclear.

METHODS

We examined the association of proteinuria severity with physical performance cross-sectionally in 3357 military young males, free of chronic kidney disease, from the cardiorespiratory fitness and hospitalization events in armed Forces (CHIEF) study in Taiwan. The grades of proteinuria were classified according to one dipstick urinalysis which were collected at morning after an 8-h fast as unremarkable (0, +/-, and 1+), moderate (2+) and severe (3+ and 4+). Aerobic physical performance was evaluated by time for a 3000-m run and anaerobic physical performance was evaluated by numbers of 2-min sit-ups and 2-min push-ups, separately. Multiple linear regressions were used to determine the relationship.

RESULTS

As compared with unremarkable proteinuria, moderate and severe proteinuria were dose-dependently correlated with 3000-m running time (β: 4.74 (95% confidence intervals (CI): - 0.55, 10.02) and 7.63 (95% CI: 3.21, 12.05), respectively), and inversely with numbers of 2-min push-ups (β = - 1.13 (- 1.97, - 0.29), and - 1.00 (- 1.71, - 0.28), respectively) with adjustments for age, service specialty, body mass index, blood pressure, alcohol intake, smoking, fasting plasma glucose, blood urea nitrogen, serum creatinine and physical activity. However, there was no association between proteinuria severity and 2-min sit-ups.

CONCLUSIONS

Our findings show a relationship of dipstick proteinuria with aerobic physical performance and parts of anaerobic physical performance in military healthy males. This mechanism is not fully understood and requires further investigations.

Six-month results of stenting of the femoropopliteal artery and predictive value of interleukin-6: Comparison with high-sensitivity C-reactive protein

OBJECTIVES

To determine the association of pre- and postinterventional serum levels of interleukin-6 and high-sensitivity C-reactive protein at the six-month evaluation of restenosis after stenting of the femoropopliteal artery.

METHODS

Sixty-eight consecutive patients with steno-occlusive femoropopliteal artery disease of Rutherford category III or IV who underwent stent implantation were included. Six-month patency was evaluated with color-coded duplex ultrasound. The association of in-stent restenosis with interleukin-6 and high-sensitivity C-reactive protein levels at baseline, and 24-h postintervention was assessed with a multivariate logistic regression analysis.

RESULTS

In-stent restenosis was found in 15 patients (22.1%) within six months. Interleukin-6 and high-sensitivity C-reactive protein levels were significantly increased at 24-h postintervention compared to their preintervention values (p < 0.001 and p = 0.002, respectively). Interleukin-6 values at baseline (odds ratio, 1.11; 95% confidence interval: 1.00, 1.23; p = 0.044) and 24-h postintervention (odds ratio, 1.04; 95% confidence interval: 1.02, 1.06; p < 0.001) were independently associated with six-month in-stent restenosis. Twenty-four-hour postinterventional high-sensitivity C-reactive protein levels were also found to be related to restenosis (odds ratio, 1.15; 95% confidence interval: 1.04, 1.26; p = 0.006), but high-sensitivity C-reactive protein levels at baseline did not show an independent association with in-stent restenosis (odds ratio, 0.57; 95% confidence interval: 0.35, 1.80; p = 0.667). Smoking, diabetes mellitus, and cumulative stent length were other parameters associated with an increased risk for in-stent restenosis.

CONCLUSIONS

Femoropopliteal artery angioplasty with stent placement induces an inflammatory response. Interleukin-6 is a powerful independent predictor of intermediate-term outcomes for stenting of the femoropopliteal artery, suggesting that its predictive value may be superior to that of high-sensitivity C-reactive protein.

Influence of smoking on levels of urinary 8-iso Prostaglandin F2α

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Cigarette smoking is an important modifiable risk factor for cardiovascular disease.

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Cigarette smoking affects oxidative stress markers such as 8-iso prostaglandin F2α.

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The effect of smoking on urinary 8-iso prostaglandin F2α levels was meta-analyzed.

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Urinary 8-iso prostaglandin F2α levels were increased in smokers.

Background

To evaluate the reduced-risk potential of alternative tobacco products, biomarkers that are involved in the biological pathways affected by cigarette smoking and smoking cessation are needed. Isoprostanes, a measure of oxidative stress, appear to be influenced by smoking and reversible upon smoking cessation and therefore could be a good biomarker. This review aims at quantifying the effect of smoking and smoking cessation on levels of urinary 8-iso prostaglandin F_2α (8-epi-PGF_2α), an isoprostane.

Methods

PubMed and Scopus databases were searched for publications that reported 8-epi-PGF_2α levels in smokers and nonsmokers as well as articles reporting the effect of smoking cessation on 8-epi-PGF_2α levels.

Results

Eighteen studies assessing 8-epi-PGF_2α levels by smoking status were identified. Five of the papers reported the results as quantity excreted in 24-hour urine (μg/24 h), and 15 reported creatinine adjusted values. The meta-analyses show increased levels of 8-epi-PGF_2α in current smokers compared with nonsmokers (mean difference = 0.16, 95% confidence interval [95%CI]: 0.14–0.19 μg/24 h with inconsistency statistic [I²] = 98%; mean difference = 172.38, 95%CI: 152.75–192.01 pg/mg creatinine with I² = 89%, respectively). There were too few publications to perform a meta-analysis assessing the effects of smoking cessation on 8-epi-PGF_2α levels.

Conclusions

Due to the high heterogeneity among the studies included in these meta-analyses, it is difficult to generalize the results; however, our study indicates increased levels of 8-epi-PGF_2α and therefore increased oxidative stress in smokers compared with nonsmokers. More studies are still needed to assess if 8-epi-PGF_2α levels are reversible after cessation.

Different association between renal hyperfiltration and mortality by sex

AIM

Renal hyperfiltration (RHF) is a marker of early kidney injury that was recently shown to be a novel marker of mortality. However, it has no clear definition. In this study, we suggested an age- and sex-adjusted RHF definition and explored the association between RHF and mortality by sex.

METHODS

We analyzed data from individuals receiving routine health examinations from 1995 to 2009. RHF was defined as an estimated glomerular filtration rate over the 95th percentile matched for age and sex.

RESULTS

A total of 114 966 individuals were included. During the 75-month of observation period, 2559 (2.2%) participants died. Among those, 71.4% were men. Because sex and RHF had a significant interaction for mortality (P for interaction < 0.001), we performed survival analysis according to sex. RHF was related to lower body weight and a higher proportion of cigarette smoking in men, whereas these relationships were not found in women. In the Kaplan-Meier curve, RHF was associated with higher mortality rate than non-RHF in both sexes, but this relationship was more prominent in men. In the multivariate analysis, RHF remained as an independent risk factor for all-cause mortality even after adjustment for confounding in men (hazard ratio, 1.34; 95% confidence interval, 1.12-1.59; P = 0.001). In women, RHF was not associated with increased mortality.

CONCLUSIONS

We demonstrated that RHF was a significant risk factor for mortality in men but not in women. The mechanisms and clinical implications of these different associations according to sex require a further clarification.

An association of smoking with serum urate and gout: A health paradox

BACKGROUND

The potential effect of cigarette smoking on levels of serum urate and risk of gout has been considered by a large number of studies, either as the primary variable of interest or as a covariate.

METHODS

Here we systematically review the published evidence relating to the relationship of smoking with serum urate, hyperuricaemia, and gout.

RESULTS

Many studies have reported that smoking reduces serum urate, however, the evidence has not been conclusive with other studies pointing to the opposite or no effect. It has also been suggested that smoking reduces the risk of gout, although there is some evidence to contradict this finding.

CONCLUSION

A consensus has yet to be reached as to the effect of smoking on serum urate levels and the risk of gout.

Cigarette smoking and cardio-renal events in patients with atherosclerotic renal artery stenosis

Cigarette smoking causes cardiovascular disease and is associated with poor kidney function in individuals with diabetes mellitus and primary kidney diseases. However, the association of smoking on patients with atherosclerotic renal artery stenosis has not been studied. The current study utilized data from the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL, NCT00081731) clinical trial to evaluate the effects of smoking on the risk of cardio-renal events and kidney function in this population. Baseline data showed that smokers (n = 277 out of 931) were significantly younger at enrollment than non-smokers (63.3±9.1 years vs 72.4±7.8 years; p<0.001). In addition, patients who smoke were also more likely to have bilateral renal artery stenoses and peripheral vascular disease (PVD). Longitudinal analysis showed that smokers experienced composite endpoint events (defined as first occurrence of: stroke; cardiovascular or renal death; myocardial infarction; hospitalization for congestive heart failure; permanent renal replacement; and progressive renal insufficiency defined as 30% reduction of GFR from baseline sustained for ≥ 60 days) at a substantially younger age compared to non-smokers (67.1±9.0 versus 76.1±7.9, p<0.001). Using linear regression and generalized linear modeling analysis controlled by age, sex, and ethnicity, smokers had significantly higher cystatin C levels (1.3±0.7 vs 1.2±0.9, p<0.01) whereas creatinine and estimated glomerular filtration rate (eGFR) were not different from non-smokers. From these data we conclude that smoking has a significant association with deleterious cardio-renal outcomes in patients with renovascular hypertension.

The prevalence of metabolic syndrome increases with serum high sensitivity C-reactive protein concentration in individuals without a history of cardiovascular disease: a report from a large Persian cohort

Background

Metabolic syndrome is defined by a clustering of cardiovascular risk factors and is associated with a heightened inflammatory state. A raised serum high-sensitivity C-reactive protein, a marker of inflammation, is also known to associate with cardiovascular risk. We have investigated the relationship between the presence of metabolic syndrome and serum high-sensitivity C-reactive protein concentration in a large representative Persian population cohort without a history of cardiovascular disease.

Methods

The MASHAD study population cohort comprised 9778 subjects, who were recruited from the city of Mashhad, Iran, between 2007 and 2008. Several cardiovascular risk factors were measured in this population without cardiovascular disease. Individuals were categorized into quartiles of serum high-sensitivity C-reactive protein concentration: first quartile – 0.72 (0.59–0.85) (median [range]) mg/L, second quartile – 1.30 (1.14–1.4) mg/L, third quartile – 2.29 (1.92–2.81) mg/L and fourth quartile – 6.63 (4.61–11.95) mg/L, respectively. The prevalence of metabolic syndrome in each quartile was determined using either International Diabetes Federation or Adult Treatment Panel III criteria.

Results

The prevalence of metabolic syndrome was highest in the fourth quartile for serum high-sensitivity C-reactive protein (1220 subjects [50.0%]), and significantly higher than that in the first quartile (reference group) (634 subjects [25.9%]) ( P < 0.001). A positive smoking habit (OR, 1.47 [1.26–1.70], P < 0.001) and the presence of either metabolic syndrome-International Diabetes Federation (OR, 1.35 [1.18–1.55], P < 0.001) or metabolic syndrome-ATPIII (OR, 1.40 [1.18–1.50], P < 0.001) were strong predictors of a fourth quartile for serum high-sensitivity C-reactive protein concentration.

Conclusions

There was a significant association between high concentrations of serum high-sensitivity C-reactive protein and the presence of metabolic syndrome among individuals without a history of cardiovascular disease in our Persian cohort.

Marker of lipid peroxidation related to diabetic nephropathy in Indonesian type 2 diabetes mellitus patients

OBJECTIVE

Even though diabetes patients exhibit an increased oxidative stress, its correlation with diabetic nephropathy is not fully understood. The purpose of this study was to determine whether lipid peroxidation marker correlates well with eGFR and UACR in type 2 diabetes mellitus patients.

METHODS

We collected urine and serum samples of Indonesian type 2 diabetes mellitus outpatients with normo- and microalbuminuria at a Local Government Clinic (from ages: 39-74 years). Urinary 8-iso-PGF2α was measured by ELISA, the serum malondialdehyde by TBARS assay, and urinary albumin by BCG albumin assay. eGFR was calculated using the corrected-Cockcroft-Gault (CG), MDRD, and CKD-EPI equation. Other necessary data were obtained through questionnaires.

RESULTS

The results showed that the increasing level of malondialdehyde was mildly correlated with the decline in eGFR (MDRD). In contrary, there was a significant positive correlation between 8-iso-PGF2α concentration and eGFR based on the corrected-CG, MDRD study, and CKD-EPI equation (r=0.457, p<0.001; r=0.424, p<0.001; r=0.443, p<0.001). This relationship still persisted in the normoalbuminuric subjects (n=43) (r=0.491, p=0.001; r=0.461, p=0.002; r=0.455, p=0.002). The multivariate analysis showed that 8-iso-PGF2α together with fasting plasma glucose was the most predictive factor for the high 2-quantile eGFR (adjusted OR 1.001, (95% CI, 1.000-1.001)). However, there was no significant correlation between UACR with malondialdehyde (r=0.268, p=0.050) and 8-iso-PGF2α(r=-0.030, p=0.808). UACR itself was inversely correlated with eGFR based on the corrected-CG, the MDRD, and CKD-EPI (r=-0.232, p<0.05; r=-0.228, p<0.05; r=-0.232, p<0.05).

CONCLUSIONS

Increased 8-iso-PGF2α and malondialdehyde in type 2 diabetes mellitus patients may play a role in the pathophysiologic significance of diabetic nephropathy, even while considering the effect of potential confounders.

A systematic review of glomerular hyperfiltration assessment and definition in the medical literature

BACKGROUND AND OBJECTIVES

Evaluation of glomerular hyperfiltration (GH) is difficult; the variable reported definitions impede comparisons between studies. A clear and universal definition of GH would help in comparing results of trials aimed at reducing GH. This study assessed how GH is measured and defined in the literature.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Three databases (Embase, MEDLINE, CINAHL) were systematically searched using the terms "hyperfiltration" or "glomerular hyperfiltration". All studies reporting a GH threshold or studying the effect of a high GFR in a continuous manner against another outcome of interest were included.

RESULTS

The literature search was performed from November 2012 to February 2013 and updated in August 2014. From 2013 retrieved studies, 405 studies were included. Threshold use to define GH was reported in 55.6% of studies. Of these, 88.4% used a single threshold and 11.6% used numerous thresholds adapted to participant sex or age. In 29.8% of the studies, the choice of a GH threshold was not based on a control group or literature references. After 2004, the use of GH threshold use increased (P<0.001), but the use of a control group to precisely define that GH threshold decreased significantly (P<0.001); the threshold did not differ among pediatric, adult, or mixed-age studies. The GH threshold ranged from 90.7 to 175 ml/min per 1.73 m(2) (median, 135 ml/min per 1.73 m(2)).

CONCLUSION

Thirty percent of studies did not justify the choice of threshold values. The decrease of GFR in the elderly was rarely considered in defining GH. From a methodologic point of view, an age- and sex-matched control group should be used to define a GH threshold.

Circulating nitrite and nitrate are associated with job-related fatigue in women, but not in men

A recent study indicated that serum nitrite and nitrate (NOx) is inversely associated with general fatigue. The purpose of this study was to confirm the negative association between nitric oxide (NO) and fatigue and to examine whether NO can prevent fatigue caused by job strain. The subjects, 570 workers (272 men and 298 women), answered self-administered questionnaires and underwent a medical examination. Job strain was measured using the Job Content Questionnaire. Fatigue was evaluated using the Profile of Mood States. Venous blood samples were collected after overnight fasting. Plasma NOx concentration was determined by the ozone-based chemiluminescence assay. Plasma NOx levels were significantly (p < 0.05) negatively associated with fatigue even after adjustment for job strain and potential confounders in women, but not in men. Significant (p < 0.05) interactions showed that, in women, as the level of the job strain worsened, fatigue was exacerbated, but the plasma NOx seemed to buffer the association, even after adjustment for potential confounders and the interaction between job strain and vegetable intake. In women, NO seemed to be inversely associated with fatigue and to buffer the association between job strain and fatigue, but not in men.

Dose-response relationships of polycyclic aromatic hydrocarbons exposure and oxidative damage to DNA and lipid in coke oven workers

Polycyclic aromatic hydrocarbons (PAHs) are known to induce reactive oxygen species and oxidative stress, but the dose-response relationships between exposure to PAHs and oxidative stress levels have not been established. In this study, we recruited 1333 male coke oven workers, monitored the levels of environmental PAHs, and measured internal PAH exposure biomarkers including 12 urinary PAH metabolites and plasma benzo[a]pyrene-r-7,t-8,t-9,c-10-tetrahydotetrol-albumin (BPDE-Alb) adducts, as well as the two oxidative biomarkers urinary 8-hydroxydeoxyguanosine (8-OHdG) and 8-iso-prostaglandin-F2α (8-iso-PGF2α). We found that the total concentration of urinary PAH metabolites and plasma BPDE-Alb adducts were both significantly associated with increased 8-OHdG and 8-iso-PGF2α in both smokers and nonsmokers (all p < 0.05). This exposure-response effect was also observed for most PAH metabolites (all p(trend) < 0.01), except for 4-hydroxyphenanthrene and 8-OHdG (p(trend) = 0.108). Furthermore, it was shown that only urinary 1-hydroxypyrene has a significant positive association with both 8-OHdG and 8-iso-PGF2α after a Bonferroni correction (p < 0.005). Our results indicated that urinary ΣOH-PAHs and plasma BPDE-Alb adducts can result in significant dose-related increases in oxidative damage to DNA and lipids. Furthermore, when a multianalyte method is unavailable, our findings demonstrate that urinary 1-hydroxypyrene is a useful biomarker for evaluating total PAHs exposure and assessing oxidative damage in coke oven workers.

The effects of continuing and discontinuing smoking on the development of chronic kidney disease (CKD) in the healthy middle-aged working population in Japan

OBJECTIVES

The strength of the association between smoking and the development of chronic kidney disease (CKD) in the healthy middle-aged working age population has not been established.

METHODS

This was a retrospective 6-year observational study involving 4,121 male and 2,877 female workers who were free of primary kidney disease, diabetes mellitus, severe hypertension, and the signs and symptoms of CKD. Proteinuria was detected by a dipstick method, and glomerular filtration rate (GFR) was estimated by the equation of the Japan Society of Nephrology.

RESULTS

Sixty men (1.5 %) and 21 women (0.7 %) developed proteinuria over the 6 years of the study. Irrespective of sex, in comparison with non-smokers, those who continued smoking showed an odds ratio (OR) of 2.52 with a 95 % confidence interval (CI) of 1.50-4.25 for developing proteinuria while those who quit smoking showed an OR of 1.29 (95 % CI 0.48-3.42), following adjustment for confounders. Among the study population, 443 men (10.7 %) and 356 women (12.4 %) developed a GFR of <60 mL/min/1.73 m(2), corresponding to stage III CKD. Continuing smokers had a low OR (0.74, 95 % CI 0.60-0.90) for developing a low GFR, as well as a higher mean GFR than non-smokers. The reduction in GFR during the 6-year study period was not different between smokers and non-smokers, but it was larger in those who developed proteinuria than in those who did not, irrespective of smoking.

CONCLUSIONS

Continuing smokers showed a twofold or more higher risk of developing proteinuria. Discontinuation of smoking substantially reduced the risk. A longer observational period may be required to detect the smoking-induced risk of developing stage III CKD in the middle-aged working population.

Smoking and chronic kidney disease in healthy populations

The objective of this review is to explore the link between smoking and the development of chronic kidney disease (CKD) in generally healthy populations without pre-existing renal dysfunction such as diabetic nephropathy. Twenty-eight epidemiological studies concerning the renal effects of smoking in the general population were collected from the MEDLINE database and were reviewed for indications of proteinuria and/or the decline of glomerular filtration rate (GFR), and evaluated on the level of evidence and the quality of the study. Sixteen of the 28 studies were cross-sectional in design. Most articles had some weakness in scope, such as the 6 articles which did not fully exclude DM patients from the subjects, the 4 that did not consider the effects of ex-smoking, and the 3 that focused on only a small number of subjects. From these cases, it is difficult to draw firm conclusions. However, proteinuria or microalbuminuria was persistently high in current smokers; as much as 5-8% or 8-15% respectively, which was up to 2 to 3-times the rate of lifelong non-smokers. On the other hand, only 5 studies broader in scope detected any decline of GFR in smokers, while 9 other studies suggested a higher GFR in smokers than in non-smokers. Two good quality studies showed an even a significantly lower risk of a decreased GFR in smokers. These paradoxical CKD markers in smokers, i.e., a higher appearance of proteinuria with a higher GFR, could be a focus for further studies to reveal the underlying reasons for smoking-induced CKD. Workplaces may be an excellent place to study this subject since the long-term changes in renal function of smokers can be observed by collecting data in the annual health check-ups mandated at places of employment.

The combined use of edaravone, diuretics, and nonsteroidal anti-inflammatory drugs caused acute kidney injury in an elderly patient with chronic kidney disease

The purpose of this study was to draw attention to the fact that the combined use of edaravone, diuretics, and nonsteroidal anti-inflammatory drugs (NSAIDs) may lead to acute kidney injury. This study was a case report of acute kidney injury resulting from the combined use of the aforementioned types of drugs. A 77-year-old male patient with chronic kidney disease (third stage) who was treated with a combination of edaravone, diuretics, and NSAIDs showed significantly increased blood urea nitrogen and creatinine. Interestingly, the blood urea nitrogen and creatinine levels returned to pretreatment levels after the medications were stopped. The patient's score on the Naranjo Adverse Drug Reaction Probability Scale was a nine, and the score on the Drug Interaction Probability Scale was a five. For elderly patients with chronic kidney disease, the combined use of edaravone, diuretics, and NSAIDs should be avoided.

Smoking cessation predicts amelioration of microalbuminuria in newly diagnosed type 2 diabetes mellitus: a 1-year prospective study

The objective of the study was to assess the effect of smoking cessation on microalbuminuria in subjects with newly diagnosed type 2 diabetes mellitus (DM). From 500 smokers newly diagnosed with type 2 DM and microalbuminuria, only 193 (96 men/97 women; age, 56.4 ± 7.8 years) agreed to participate and were educated on smoking cessation, diet, and exercise. Pharmacological interventions were not different among the studied groups. All subjects were contacted by phone monthly with emphasis on smoking cessation. Anthropometric, biochemical parameters and urine specimens were obtained at baseline and at 12-month follow-up. Microalbuminuria was defined as an albumin to creatinine ratio of 30 to 299.9 μg/mg creatinine. Ankle brachial pressure index was determined by ultrasound. A total of 120 (62.2%) subjects quit smoking. Prevalence of microalbuminuria was reduced at 1 year to 72.6% in the subjects who quit smoking and to 22.5% in those who continued smoking (P = .015). Multivariate logistic regression analysis demonstrated that independently associated with the reduction in albumin to creatinine ratio (84.8 vs 28.7 μg/mg creatinine) were amelioration of glycemic control (P < .001), blood pressure (P = .02), dyslipidemia (P = .02), and insulin resistance (P = .05). Smoking cessation also reduced the prevalence of peripheral vascular disease (P = .03) and neuropathy (P = .04). From the pharmacological and lifestyle interventions, smoking cessation had the highest and an independent contribution to the reduction of microalbuminuria (P < .001). Smoking cessation in newly diagnosed type 2 DM patients is associated with amelioration of metabolic parameters, blood pressure, and the reduction of microalbuminuria. Stricter counseling about the importance of quitting smoking upon type 2 DM diagnosis is necessary to protect against the development of diabetic nephropathy and vascular complications.

Cigarette smoking, proteinuria, and renal function in middle-aged Japanese men from an occupational population

OBJECTIVES

To clarify the renal effects of cigarette smoking in a middle-aged occupational population because the effects have previously been demonstrated mainly in community populations that included many elderly people who are thought to be vulnerable to such effects.

METHODS

In 990 middle-aged men recruited from a chemical plant, proteinuria was measured by a dipstick method and the glomerular filtration rate was estimated (eGFR) using a formula proposed by the Japanese Society of Nephrology.

RESULTS

Proteinuria was found in 4.6% of the current smokers and 1.5% of the never-smokers. It was found in 4.8% of the subjects having a Brinkman index (BI) of 400-599 and 6.3% of those having a BI of 600 or above. The odds ratio for proteinuria in them was 2.94 (CI: 1.01-8.55) and 3.61 (CI: 1.29-10.1), respectively, adjusting for possible confounders. The mean eGFR was higher in smokers than in nonsmokers throughout middle age up to 64 years. Normal but high eGFR was found in 6.7% of the current heavy smokers and subnormal eGFR in 5.7% of the largest cumulative cigarette consumers in contrast to 3.0% or less of the never-smokers. Proteinuria was found in 13.3% of the subjects showing subnormal eGFR, specifically in 16.7% of the smokers and 8.3% of the nonsmokers.

CONCLUSIONS

Smoking causes proteinuria in working middle-aged men. Smokers tend to have a high eGFR, but those with subnormal eGFR showed proteinuria most frequently. Whether the high eGFR in smokers will eventually decrease and cause proteinuria remains an important focus for further studies.