Adverse effect of smoking on renal function in the general population: are men at higher risk?

Sex-based differences in myocardial infarction-induced kidney damage following cigarette smoking exposure: more renal protection in premenopausal female mice

The impact of cigarette smoking (CS) on kidney homeostasis in the presence of myocardial infarction (MI) in both males and females remains poorly elucidated. C57BL6/J mice were exposed to 2 weeks of CS prior to MI induction followed by 1 week of CS exposure in order to investigate the impact of CS on kidney damage in the presence of MI. Cardiac hemodynamic analysis revealed a significant decrease in ejection fraction (EF) in CS-exposed MI male mice when compared with the relative female subjects, whereas cardiac output (CO) comparably decreased in CS-exposed MI mice of both sexes. Kidney structural alterations, including glomerular retraction, proximal convoluted tubule (PCT) cross-sectional area, and total renal fibrosis were more pronounced in CS-exposed MI male mice when compared with the relative female group. Although renal reactive oxygen species (ROS) generation and glomerular DNA fragmentation significantly increased to the same extent in CS-exposed MI mice of both sexes, alpha-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF) significantly increased in CS-exposed MI male mice, only. Metabolically, nicotinamide phosphoribosyltransferase (NAMPT) and nicotinamide riboside-1 (NMRK-1) substantially increased in CS-exposed MI female mice only, whereas sirtuin (SIRT)-1 and SIRT-3 substantially decreased in CS-exposed MI male mice compared with their relative female group. Additionally, renal NAD levels significantly decreased only in CS-exposed MI male mice. In conclusion, MI female mice exhibited pronounced renal protection following CS when compared with the relative male groups.

Increased Microalbuminuria Risk in Male Cigarette Smokers: Results from the “Olivetti Heart Study” after 8 Years Follow-Up

Background/Aims: Association between cigarette smoke and albuminuria (UA) was already demonstrated in cross-sectional studies and in selected population samples (i.e diabetic patients). This study aims to evaluate, prospectively, the relationship between cigarette smoke and UA in a male adult population sample, with basal normal kidney function, participating in the Olivetti Heart Study (OHS). Methods: Among 994 participants, examined in both 1994-95 and 2002-04, were selected those resulted in both visits smokers (n=221) and non-smokers (n=416) and with basal normal kidney function (GFR> 60 mL/min) and basal albumin/creatinine ratio (ACR< 30 mg/g). Results: At baseline, the prevalence of hypertension was 41%, diabetes affected 6.3% and obesity 17% of the whole sample. Smokers showed statistically significant lower levels of systolic (SBP) and diastolic blood pressure (DBP) and BMI (p< 0.001) compared to non-smokers. There were not basal differences in UA, GFR and metabolic profile. However, at follow-up examination, smokers showed a statistically significant increase in SBP and DBP (p< 0.05), but not in GFR and BMI. Moreover, smokers showed a higher risk compared to non-smokers to be in the higher median levels group of UA (OR: 2.17, C.I.95%: 1.51-3.13; p < 0.001), even after correction for major confounding factors. Further adjustment for basal antihypertensive and hypoglycemic treatment did not change these patterns of association. Conclusion: In a selected male adult population sample, cigarette smoke was independently associated with the development of higher levels of albuminuria over time.

Prevalence of smoking and clinical characteristics in fibromuscular dysplasia. The ARCADIA-POL study

PURPOSE

Smoking was identified as a potential factor contributing to fibromuscular dysplasia (FMD). To evaluate the prevalence of smoking and clinical characteristics in FMD subjects.

MATERIAL AND METHODS

We analysed 190 patients with confirmed FMD in at least one vascular bed. The rate of smokers in FMD patients was compared to that in two control groups selected from a nationwide survey.

RESULTS

The rate of smokers in FMD patients was 42.6%. There were no differences in frequency of smokers between FMD patients and: a group of 994 matched control subjects from general population and a group of matched hypertensive subjects. There were no differences in the characteristics of FMD (including rates of multisite FMD and significant renal artery stenosis) and its complications (including rates of dissections and aneurysms) between smokers and non-smokers. Smokers as compared with non-smokers were characterized by higher left ventricle mass index.

CONCLUSIONS

There is no difference in the rate of smokers between FMD patients and subjects from the general population. Moreover, we did not find any association between smoking and clinical characteristics of FMD patients nor its extent and vascular complications. Our results do not support the hypothesis that smoking is involved in the pathophysiology of FMD.

Risk Factors for Rapid Kidney Function Decline Among African Americans: The Jackson Heart Study (JHS)

BACKGROUND

Racial differences in rapid kidney function decline exist, but less is known regarding factors associated with rapid decline among African Americans. Greater understanding of potentially modifiable risk factors for early kidney function loss may help reduce the burden of kidney failure in this high-risk population.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

3,653 African American participants enrolled in the Jackson Heart Study (JHS) with kidney function data from 2 of 3 examinations (2000-2004 and 2009-2013). Estimated glomerular filtration rate (eGFR) was calculated from serum creatinine using the CKD-EPI creatinine equation.

PREDICTORS

Demographics, socioeconomic status, lifestyle, and clinical risk factors for kidney failure.

OUTCOMES

Rapid decline was defined as a ≥30% decline in eGFR during follow-up. We quantified the association of risk factors with rapid decline in multivariable models.

MEASUREMENTS

Clinical (systolic blood pressure and albuminuria [albumin-creatinine ratio]) and modifiable risk factors.

RESULTS

Mean age was 54±12 (SD) years, 37% were men, average body mass index was 31.8±7.1kg/m(2), 19% had diabetes mellitus (DM), and mean eGFR was 96.0±20mL/min/1.73m(2) with an annual rate of decline of 1.27mL/min/1.73m(2). Those with rapid decline (11.5%) were older, were more likely to be of low/middle income, and had higher systolic blood pressures and greater DM than those with nonrapid decline. Factors associated with ≥30% decline were older age (adjusted OR per 10 years older, 1.51; 95% CI, 1.34-1.71), cardiovascular disease (adjusted OR, 1.53; 95% CI, 1.12-2.10), higher systolic blood pressure (adjusted OR per 17mmHg greater, 1.22; 95% CI, 1.06-1.41), DM (adjusted OR, 2.63; 95% CI, 2.02-3.41), smoking (adjusted OR, 1.60; 95% CI, 1.10-2.31), and albumin-creatinine ratio > 30mg/g (adjusted OR, 1.55; 95% CI, 1.08-1.21). Conversely, results did not support associations of waist circumference, C-reactive protein level, and physical activity with rapid decline.

LIMITATIONS

No midstudy creatinine measurement at examination 2 (2005-2008).

CONCLUSIONS

Rapid decline heterogeneity exists among African Americans in JHS. Interventions targeting potentially modifiable factors may help reduce the incidence of kidney failure.

[Kidney and smoking: literature review and focus]

Smoking remains a major public health problem. It is associated with a considerable number of deaths in the world's population. Smoking is just like high blood pressure, an independent predictor of progression to any primary renal disease and renal transplant patients. It seems that smoking cessation slows the progression of kidney disease in smokers. The literature data are sometimes contradictory about it because of some methodological weaknesses. However, experimental models highlight the harmful effects of tobacco by hemodynamic and non-hemodynamic factors. The conclusion is that a major effort should be further produced by the nephrology community to motivate our patients to stop smoking.

The threshold level of urinary cadmium associated with increased urinary excretion of retinol-binding protein and beta 2-microglobulin: a re-assessment in a large cohort of nickel-cadmium battery workers

OBJECTIVE

To evaluate the threshold value of urinary cadmium (CdU) for renal dysfunction on the basis of relationships unconfounded by protein degradation, diuresis and the renal effects associated with chronic smoking. Methods We studied 599 workers (451 men, mean age 45.4 years) who were employed in four nickel-cadmium battery plants for 18.8 years on average. After adjustment for covariates by multiple regression, the CdU threshold values for increased concentrations of retinol-binding protein (RBPU) and b(2)-microglobulin (b(2)-mU) were assessed by logistic regression and benchmark dose analyses using as referents workers with CdU<1 μg/g creatinine. Results Relationships between urinary proteins and CdU (μg/g creatinine) were influenced by sex, age, diuresis and especially smoking. When considering all workers, odds for abnormal RBPU and b(2)-mU were significantly increased from CdU of 6-10 and >10, respectively. The benchmark dose (BMD5) and the benchmark dose lower limit (BMDL5) for a 5% excess in the background prevalence of abnormal RBPU and b(2)-mU were estimated at 5.1/3.0 and 9.6/5.9. When excluding ever smokers, odds for abnormal RBPU and b(2)-mU were both increased only among workers with CdU>10 (OR, 21.8, 95% CI, 6.4-74.4 and OR, 15.1, 95% CI, 3.6-63.1, respectively). In never smokers, these BMD5/BMDL5 of CdU were estimated at 12.6/6.6 and 12.2/5.5 while in ever smokers they were 6.2/4.9 and 4.3/3.5. Conclusions On the basis of associations undistorted by smoking and adjusted for covariates, the BMDL5 of CdU for low-molecular-weight proteinuria induced by occupational exposure to Cd can be reliably estimated between 5.5 and 6.6 μg/g creatinine.

Smoking: a risk factor for progression of chronic kidney disease and for cardiovascular morbidity and mortality in renal patients--absence of evidence or evidence of absence?

Although it is beyond any doubt that smoking is the number one preventable cause of death in most countries, smoking as an independent progression factor in renal disease has been questioned against the background of evidence-based criteria. This is because information from large, randomized, prospective studies that investigate the effects of smoking on renal function in healthy individuals as well as in patients with primary or secondary renal disease are lacking. Since 2003, a substantial number of clinical and experimental data concerning the adverse renal effects of smoking have been published, including large, prospective, population-based, observational studies. These more recent data together with evidence from experimental studies clearly indicate that smoking is a relevant risk factor, conferring a substantial increase in risk for renal function deterioration. This review summarizes the present knowledge about the renal risks of smoking as well as the increased cardiovascular risk caused by smoking in patients with chronic kidney disease. The conclusion is that smoking is an important renal risk factor, and nephrologists have to invest more efforts to motivate patients to stop smoking.

Smoking induces glomerulosclerosis in aging estrogen-deficient mice through cross-talk between TGF-beta1 and IGF-I signaling pathways

Smoking is a known risk factor for the progression of chronic kidney diseases. However, its independent contribution to the development of ESRD and the underlying molecular mechanism have not been well elucidated. Although the risk for ESRD is higher in postmenopausal women according to the US Renal Data System, the number of women who smoke is on the rise worldwide. Therefore, the effects of smoking and estrogen status on glomerular function and structure were studied in female B6 mice that were ovariectomized at 3 (young) and 15 mo (aged) of age. The mice received either 17beta-estradiol (E(2)) replacement or placebo (Pla) and were divided further into groups that were exposed to cigarette smoke (S) and not exposed (NS). Six months of exposure to smoke had no effect on young mice, although aging S/Pla mice exhibited a phenotype of increased albumin excretion associated with a moderately increased glomerular collagen type IV deposition compared with NS/Pla mice. S/Pla mice also had a two-fold increase in glomerular TGF-beta, Smad3, and IGF-I receptor mRNA expression compared with the NS group. Mesangial cells that were isolated from S/Pla mice had an increase of IGF-I receptor protein, and IGF-I stimulated a TGF-beta reporter construct promoter three-fold. This was blocked by pretreatment with a neutralizing antibody to IGF-I, LY294002 (phosphatidylinositol-3 kinase inhibitor) or a dominant negative Smad construct. In addition, Smad3 activation was stimulated by IGF-I and blocked by LY294002, suggesting cross-talk between Smad and the phosphatidylinositol-3 kinase/AKT pathways. The smoking phenotype was reversed by E(2) replacement. In conclusion, smoking induces a phenotype in E(2)-deficient mice that is characterized by activation and cross-talk between the TGF-beta1 and IGF-I signaling pathways.

Lifestyle modification and progressive renal failure

There is increasing evidence that lifestyle factors impact on the risk of developing chronic kidney disease (CKD) and the risk of progression of CKD. Equally important is the consideration that patients with CKD are more likely to die from cardiovascular disease than to reach the stage of end-stage renal failure. It is advantageous that manoeuvres that interfere with progression at the same time also reduce the risk of cardiovascular events. Lifestyle factors that aggravate progression include, among others, smoking, obesity and dietary salt intake. Alcohol consumption, according to some preliminary information, has a bimodal relationship to cardiovascular risk and progression, with moderate consumption being protective.

Preventing Type 2 diabetes and the dysmetabolic syndrome in the real world: a realistic view

The last two decades have seen an explosive increase in the number of people with diabetes globally. There is now an urgent need for strategies to prevent the emerging global epidemic. Several recent successful intervention studies, both lifestyle and pharmacological, targeting subjects with impaired glucose tolerance (IGT) have stimulated enthusiasm for prevention of Type 2 diabetes. Lifestyle interventions reduced the incidence of diabetes by over 50% in the Finnish Diabetes Prevention Study and the Diabetes Prevention Program. Can the findings of these two studies be applied globally? Underpinning the enthusiasm, there needs to be a realistic approach to interventions in both developed and developing nations, and in ethnic groups where a better understanding of the socio-economic, cultural and demographic issues and perceptions surrounding chronic diseases such as diabetes is required. Whether the strategies used in these two studies can be translated into a 'real world' scenario is doubtful. In practice, it is more than likely that a number of strategies will be needed to compliment the lifestyle approach. These will include pharmacological approaches with metformin, acarbose and other agents used to treat diabetes and its complications, currently under investigation. Longer-term follow-up studies will also clarify whether both lifestyle and pharmacological interventions actually prevent Type 2 diabetes, or merely delay its onset.

Cigarette smoking: an important renal risk factor - far beyond carcinogenesis

In recent years, it has become apparent that smoking has a negative impact on renal function, being one of the most important remediable renal risk factors. It has been clearly shown that the risk for high-normal urinary albumin excretion and microalbuminuria is increased in smoking compared to non-smoking subjects of the general population. Data from the Multiple Risk Factor Intervention Trial (MRFIT) indicate that at least in males, smoking increases the risk to reach end-stage renal failure. Smoking is particularly "nephrotoxic" in older subjects, subjects with essential hypertension and patients with preexisting renal disease. Of interest, the magnitude of the adverse renal effect of smoking seems to be independent of the underlying renal disease. Death-censored renal graft survival is decreased in smokers, indicating that smoking also damages the renal transplant. Cessation of smoking has been show to reduce the rate of progression of renal failure both in patients with renal disease or a renal transplant. The mechanisms of smoking-induced renal damage are only partly understood and comprise acute hemodynamic (e.g., increase in blood pressure and presumably intraglomerular pressure) and chronic effects (e.g., endothelial cell dysfunction). Renal failure per se leads to an increased cardiovascular risk. The latter is further aggravated by smoking. Particularly survival of smokers with diabetes mellitus on hemodialysis is abysmal. In the present review article the current state of knowledge about the renal risks of smoking is reviewed. It is the aim of the article to point out that smoking not only increases the risk of renal cell carcinoma or uroepithelial cell carcinoma, but also the risk of a faster decline of renal function. The latter is a relatively new negative aspect which has not been widely recognized.