Serum adiponectin is associated with smoking status in healthy Korean men

The Effects of Smoking on the Diagnostic Characteristics of Metabolic Syndrome: A Review

Metabolic syndrome is a growing epidemic that increases the risk for cardiovascular disease, diabetes, stroke, and mortality. It is diagnosed by the presence of three or more of the following risk factors: 1) obesity, with an emphasis on central adiposity, 2) high blood pressure, 3) hyperglycemia, 4) dyslipidemia, with regard to reduced high-density lipoprotein concentrations, and 5) dyslipidemia, with regard to elevated triglycerides. Smoking is one lifestyle factor that can increase the risk for metabolic syndrome as it has been shown to exert negative effects on abdominal obesity, blood pressure, blood glucose concentrations, and blood lipid profiles. Smoking may also negatively affect other factors that influence glucose and lipid metabolism including lipoprotein lipase, adiponectin, peroxisome proliferator-activated receptors, and tumor necrosis factor-alpha. Some of these smoking-related outcomes may be reversed with smoking cessation, thus reducing the risk for metabolic disease; however, metabolic syndrome risk may initially increase post cessation, possibly due to weight gain. Therefore, these findings warrant the need for more research on the development and efficacy of smoking prevention and cessation programs.

Relationship between Plasma Adiponectin Level and Corrected QT Interval in Smoker and Non-smoker Adult Male Subjects

Objective

This study determined the relationship between plasma adiponectin level and corrected QT interval (QTc) in smokers and non-smokers.

Methodology

This cross-sectional analytical study was undertaken in 30 smokers and 30 non-smokers. Plasma adiponectin level was determined by enzyme-linked immunosorbent assay (ELISA). The QT interval was measured by routine 12-lead ECG with Lead II rhythm and QTc was calculated.

Results

Mean plasma adiponectin level was significantly lower in smokers (27.89±15 μg/ml) than that of non-smokers (52.13±21.57pg/ml) (p<0.001). Mean QTc interval was significantly longer in smokers than that of non-smokers (415.37±29.9 versus 395.63±26.13 ms, p<0.01). Higher risk of low adiponectin level (odds ratio [OR],8.1; 95% confidence interval [CI],1.61-40.77) and QTc interval prolongation (OR,6; 95%CI,1.17-30.73) were observed in smokers. There was weak significant negative correlation between plasma adiponectin level and QTc interval in the study population (n=60, r=-0.407, p=0.001). Moreover, low plasma adiponectin level was significantly associated with prolonged QTc interval in the study population (n=60, Fisher's exact p value<0.05). Risk of QTc interval prolongation was 4.3 times higher in subjects with low plasma adiponectin level (OR,4.27; 95% CI,1.05-17.46).

Conclusion

Smokers have greater risk for low plasma adiponectin level and prolonged QTc interval. There is a relationship between plasma adiponectin level and QTc interval.

Obesity, insulin resistance, adiponectin, and PPAR-γ gene expression in broiler chicks fed diets supplemented with fat and green tea (Camellia sinensis) extract

Adipose tissue is an active endocrine organ secreting several adipokines, especially adiponectin, that play an important role in regulating insulin function in the body of mammals. Therefore, this study was aimed to investigate the association between abdominal fat deposit, insulin resistance, peroxisome proliferator-activated receptor gamma (PPAR-γ), and adiponectin gene (AG) expression in broiler chicks fed diets high in unsaturated fat supplemented with green tea extract (GTE). A total of 300 one-day-old female Ross 308 broiler chicks were allocated to 6 dietary treatments in a completely randomized design with a factorial arrangement of two levels of GTE (0 and 500 mg/kg diet) × three levels of fat inclusion [without fat (control group), soybean oil (SO), and tallow (Ta)]. Each treatment was replicated five times. At the end of the experiment (day 49), two chicks from each replicate weighing an average of pen weight were bled and then slaughtered for further analysis. Abdominal fat percentage, fasting concentration of blood glucose, triglyceride and insulin, glycogen reserves of breast and liver tissues, and PPAR-γ and AG expression were determined. The insulin resistance index of the Quantitative Insulin Sensitivity Check Index (QUICKI) was calculated using the fasting plasma glucose and insulin concentrations. The highest abdominal fat percentage and the lowest carcass yield were obtained in chicks fed SO-supplemented diet (P < 0.05). Chicks fed diet supplemented with SO showed the highest PPAR-γ gene expression (P < 0.05). SO-rich diets suppressed AG expression in chickens' abdominal fat tissue, and the birds fed with SO-supplemented diet showed a significant decrease in AG expression compared with the control (P < 0.05). Chicks fed diet supplemented with SO showed lower QUICKI and breast glycogen reserve compared with the control group (P < 0.05). A significant increase in blood glucose and triglyceride concentrations was observed in birds fed SO-supplemented diets (P < 0.05). AG and PPAR-γ expression increased and decreased by GTE, respectively. QUICKI tended (P = 0.09) to be greater in GTE-supplemented chicks; however, the effect of GTE supplementation on carcass yield, abdominal fat percentage, and blood insulin and glucose concentration was not significant. The findings of this study showed that SO-rich diets via increased PPAR-γ gene expression and decreased AG expression in abdominal fat may lead to insulin resistance in female broiler chicks.

The Impact of Aging on Adipose Function and Adipokine Synthesis

During the last 40 years, there has been a world-wide increase in both the prevalence of obesity and an increase in the number of persons over the age of 60 due to a decline in deaths from infectious disease and the nutrition transition in low and middle income nations. While the increase in the elderly population indicates improvements in global public health, this population may experience a diminished quality of life due to the negative impacts of obesity on age-associated inflammation. Aging alters adipose tissue composition and function resulting in insulin resistance and ectopic lipid storage. A reduction in brown adipose tissue activity, declining sex hormones levels, and abdominal adipose tissue expansion occur with advancing years through the redistribution of lipids from the subcutaneous to the visceral fat compartment. These changes in adipose tissue function and distribution influence the secretion of adipose tissue derived hormones, or adipokines, that promote a chronic state of low-grade systemic inflammation. Ultimately, obesity accelerates aging by enhancing inflammation and increasing the risk of age-associated diseases. The focus of this review is the impact of aging on adipose tissue distribution and function and how these effects influence the elaboration of pro and anti-inflammatory adipokines.

Different forms of adiponectin reduce the apoptotic and damaging effect of cigarette smoke extract on human bronchial epithelial cells

Chronic obstructive pulmonary disease (COPD) is a common respiratory disease, in which adiponectin may serve an important role. The present study investigated the role of adiponectin in the apoptotic and damaging effect of cigarette smoke extract (CSE) on human bronchial epithelial cells (16HBECs). An MTT assay showed that CSE significantly inhibited the proliferation of 16HBECs (F=1808.88, P<0.01). The 16HBECs were treated with different concentrations of high molecular weight (HMW) adiponectin and globular domain (gAd) adiponectin and it was observed that HMW and gAd dose-dependently inhibited the expression of tumor necrosis factor (TNF)-α and interleukin (IL)-8, and the generation of 4-hydroxy-nonenal and reactive oxygen species (ROS) in 16HBECs, thereby blocking the upregulating effect of CSE on these factors. However, the inhibitory effect of gAd on TNF-α and IL-8 expression was stronger compared with that of HMW, but the suppressing effect of HMW on ROS production was superior compared with that of gAd. Further testing of apoptosis indicated that CSE and HMW promoted the apoptosis of 16HBECs. However, such effects of HMW declined with an increase in concentration. In contrast, gAd showed an inhibitory effect on apoptosis and inhibited the occurrence of CSE-induced apoptosis in a dose-dependent manner. Therefore, the present study demonstrated that different forms of adiponectin may have different mechanisms of action, suggesting that further exploration of their effects may open a new avenue for the treatment of COPD.

Adiponectin resistance in skeletal muscle: pathophysiological implications in chronic heart failure

Skeletal muscle wasting is a common complication of chronic heart failure (CHF) and linked to poor patient prognosis. In recent years, adiponectin was postulated to be centrally involved in CHF-associated metabolic failure and muscle wasting. This review discusses current knowledge on the role of adiponectin in CHF. Particular emphasis will be given to the complex interaction mechanisms and the intracellular pathways underlying adiponectin resistance in skeletal muscle of CHF patients. In this review, we propose that the resistance process is multifactorial, integrating abnormalities emanating from insulin signalling, mitochondrial biogenesis, and ceramide metabolism.

The role of adipokines in chronic inflammation

Adipose tissue has traditionally been defined as connective tissue that stores excess calories in the form of triacylglycerol. However, the physiologic functions attributed to adipose tissue are expanding, and it is now well established that adipose tissue is an endocrine gland. Among the endocrine factors elaborated by adipose tissue are the adipokines; hormones, similar in structure to cytokines, produced by adipose tissue in response to changes in adipocyte triacylglycerol storage and local and systemic inflammation. They inform the host regarding long-term energy storage and have a profound influence on reproductive function, blood pressure regulation, energy homeostasis, the immune response, and many other physiologic processes. The adipokines possess pro- and anti-inflammatory properties and play a critical role in integrating systemic metabolism with immune function. In calorie restriction and starvation, proinflammatory adipokines decline and anti-inflammatory adipokines increase, which informs the host of energy deficits and contributes to the suppression of immune function. In individuals with normal metabolic status, there is a balance of pro- and anti-inflammatory adipokines. This balance shifts to favor proinflammatory mediators as adipose tissue expands during the development of obesity. As a consequence, the proinflammatory status of adipose tissue contributes to a chronic low-grade state of inflammation and metabolic disorders associated with obesity. These disturbances are associated with an increased risk of metabolic disease, type 2 diabetes, cardiovascular disease, and many other pathological conditions. This review focuses on the impact of energy homeostasis on the adipokines in immune function.

Association of hypoadiponectemia with smokeless/dipping tobacco use in young men

BACKGROUND

Low levels of adiponectin, an adipocytokine with anti-diabetic, antiatherogenic and cardioprotective properties, is associated with increased risk of coronary disease in young men. Previous studies have demonstrated that smokeless tobacco is linked with a reduction of plasma adiponectin levels. However, the influence of smokeless tobacco (dipping tobacco) on plasma adiponectin levels still remains unknown. This study was conducted to assess the plasma adiponectin levels in young men who were using dipping tobacco.

METHODS

This was a community based study, which consisted of 186 young lean healthy males aged 20 to 35 years. Among these, 96 men were dipping tobacco users (BMI = 23.07 ± 2.68) and 90 were non-dipping tobacco users (BMI = 23.67 ± 1.46). Serum adiponectin levels were assessed by Enzyme Linked ImmunoSorbent Assay (ELISA).

RESULTS

A statistically significant difference in the mean adiponectin level between tobacco dipper and non-dipper groups was observed (p = 0.0001). A significant difference between the two groups was also observed in baseline parameters including triglyceride and random blood sugar levels (p < 0.05). However, no significant difference was observed between the two groups in other clinical parameters.

CONCLUSIONS

Findings of this study suggest that dipping tobacco use was significantly associated with low level of adiponetin in community dwelling young males. This emphasizes the importance of developing community intervention to reduce the use of dipping tobacco, which will reduce the tobacco associated disease burden in the community and will improve public health.

Smoking and diabetes: is the association mediated by adiponectin, leptin, or C-reactive protein?

Background

Although the association between cigarette smoking and risk of type 2 diabetes is well established, its mechanisms are yet to be clarified. This study examined the possible mediating effects of adiponectin, leptin, and C-reactive protein (CRP) concentrations on the smoking-diabetes association.

Methods

Between 2002 and 2011, we followed 3338 Japanese workers, aged 35–66 years, who were enrolled in the second Aichi workers’ cohort study. We used multivariable-adjusted Cox regression models to determine the hazard ratios and respective 95% confidence intervals (CIs) of the association between smoking status and risk of diabetes. A multiple mediation model with bootstrapping was used to estimate the magnitude and the respective bias-corrected (BC) 95% CIs of the indirect effects of smoking on diabetes through the three biomarkers.

Results

Relative to never smokers, the risk of diabetes was significantly elevated in current (hazard ratio 1.75, 95% CI 1.25–2.46) and ex-smokers (hazard ratio 1.54, 95% CI 1.07–2.22). The indirect effects of smoking on diabetes through adiponectin levels were statistically significant among light (point estimate 0.033, BC 95% CI 0.005–0.082), moderate (point estimate 0.044, BC 95% CI 0.010–0.094), and heavy smokers (point estimate 0.054, BC 95% CI 0.013–0.113). In contrast, neither the indirect effects of smoking on diabetes through leptin nor CRP levels were significant, as the corresponding BC 95% CIs included zero.

Conclusions

In our analysis, adiponectin concentration appeared to partially mediate the effect of smoking on diabetes, while leptin and CRP levels did not.

Cardiometabolic effects of adiponectin

Over the past two decades, adiponectin has been studied in more than eleven thousand publications. A classical adipokine, adiponectin was among the first factors secreted from adipose tissue that were found to promote metabolic function. Circulating levels of adiponectin consistently decline with increasing body mass index. Clinical and basic science studies have identified adiponectin's cardiovascular-protective actions, providing a mechanistic link to the increased incidence of cardiovascular disease in obese individuals. While progress has been made in identifying receptors essential for the metabolic actions of adiponectin (AdipoR1 and AdipoR2), few studies have examined the receptor-mediated signaling pathways in cardiovascular tissues. T-cadherin, a GPI-anchored adiponectin-binding protein, was recently identified as critical for the cardiac-protective and revascularization actions of adiponectin. Adiponectin is abundantly present on the surfaces of vascular and muscle tissues through a direct interaction with T-cadherin. Consistent with this observation, adiponectin is absent from T-cadherin-deficient tissues. Since T-cadherin lacks an intracellular domain, additional studies would further our understanding of this signaling pathway. Here, we review the diverse cardiometabolic actions of adiponectin.

The association of adiponectin with computed tomography phenotypes in chronic obstructive pulmonary disease

RATIONALE

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disorder associated with systemic manifestations that contribute to its morbidity and mortality. Recent work suggests that biomarker signatures in the blood may be useful in evaluating COPD phenotypes and may provide insight into the pathophysiology of systemic manifestations. Adiponectin, primarily produced by fat cells, has been implicated in the pathophysiology of emphysema.

OBJECTIVES

To investigate the association of adiponectin with clinical and radiologic COPD phenotypes.

METHODS

Adiponectin levels were determined in 633 individuals, including 432 individuals with COPD from a cohort of former or current smokers enrolled in the COPDGene study. Univariate and multiple regression analysis were used to examine the association of adiponectin with clinical and physiologic data together with quantitative high-resolution computed tomography parameters.

MEASUREMENTS AND MAIN RESULTS

Multiple regression analysis confirmed that higher plasma adiponectin levels were independently associated with emphysema, decreasing body mass index, female sex, older age, and lower percentage change in prebronchodilator/post-bronchodilator FEV1.

CONCLUSIONS

The association between plasma adiponectin and computed tomography-assessed emphysema suggests a contribution of adiponectin to the development of emphysema and highlights a role for metabolic derangements in the pathophysiology of emphysema.

Expression of adiponectin receptor 1 is indicative of favorable prognosis in non-small cell lung carcinoma

Lung cancer is a major cause of cancer-related death worldwide. It is believed that obesity-related malignancies such as breast, endometrial, colorectal, and kidney carcinomas have lower plasma level and/or tissue expression of adiponectin receptors. However, the association between adiponectin receptors and lung cancer, a non obesity-related malignancy, is still unknown. We evaluated the tissue expression of adiponectin receptor (AdipoR) 1 and AdipoR2 in 83 cases of non-small cell lung carcinoma (NSCLC) and matched non-neoplastic lung tissues by immunohistochemistry and real-time polymerase chain reaction (PCR). Clinicopathological data, including smoking history, smoker's bronchiolitis, emphysema, lymph node metastasis, and T-stage were collected and evaluated. Expression of immunohistochemically stained AdipoR1 and AdipoR2 was observed in all samples of non-neoplastic lung tissues. Both receptors showed higher mRNA expression in non-neoplastic than neoplastic tissues (p < 0.05). In NSCLC tissues, AdipoR1 immunohistochemical expression was not observed in most of patients with squamous cell carcinoma and current smoking history (31/42, p = 0.04 and 25/29, p = 0.003, respectively). Additionally, AdipoR1 mRNA expression was significantly lower in patients with lymph node metastasis (p = 0.05). Meanwhile, AdipoR2 immunohistochemical stain expression was inversely correlated with T-stage (p = 0.05) and AdipoR2 mRNA expression was significantly lower in patients with smoker's bronchiolitis (p = 0.01) and emphysema (p = 0.03). Patients with expression of AdipoR1 had longer overall survival. AdipoR2 expression was not correlated with patients' survival. In conclusion, we suggest that expression of AdipoR1 is indicative of favorable prognosis and may be used as prognostic marker in NSCLC.

The relationship between a Mediterranean diet and circulating adiponectin levels is influenced by cigarette smoking

AIM

Adherence to a Mediterranean diet has been shown to lower the risk of developing several chronic diseases. The ability to augment circulating adiponectin levels is proposed as an underlying mechanism mediating the beneficial effects of this diet. We aimed to examine whether the positive relationship between the Mediterranean diet and adiponectin is altered by cigarette smoking, taking potential confounders into consideration.

METHODS

Plasma adiponectin levels were enzymatically measured in 45 never smokers, 61 smokers and 34 ex-smokers who adhered to a Mediterranean style diet and in 41 never smokers who did not adhere to the diet.

RESULTS

Plasma adiponectin levels increased significantly in nonsmoking diet adherents compared to nonsmoking non-diet adherents. Among the diet adherents adiponectin decreased significantly in both moderate and heavy smokers compared to never smokers and significantly increased in quitters compared to smokers. Multiple regression analysis, controlling for age, obesity, Mediterranean diet and insulin resistance revealed an independent inverse association of smoking with adiponectin. Adiponectin levels remained significant and similar in subjects stratified according to age (</>50 years), BMI (</>25 kg/m(2)) and HOMA-IR (</>1.6).

CONCLUSIONS

Despite its positive effects on adiponectin, the Mediterranean diet failed to negate the adiponectin-lowering effect of cigarette smoking, demonstrating the profound and independent capacity of cigarette smoke to negatively influence human health.

Effects of smoking and obesity on the association between CDH13 (rs3865188) and adiponectin among Korean men: the KARE study

Adiponectin is secreted exclusively by adipocytes. Adiponectin is regulated by obesity, smoking, and genetic factors, including CDH13, which may contribute to development of diseases such as cardiovascular disease. Therefore, we aim to explore the joint effect of smoking and obesity on the association between CDH13 (rs3865188) and adiponectin among Korean men. This study included 1,570 Korean men aged 40-69 years who participated in the KARE cohort study (community-based cohorts, South Korea) from 2001. Hypoadiponectinemia was defined as the lowest quartile of adiponectin. In this study, individuals with at least one at-risk allele, the T allele, had an increased risk for hypoadiponectinemia, particularly current smokers with at least one T allele together with obesity when compared to those without the T allele. In addition, individuals with the TT genotype of CDH13 rs3865188, as well as obesity, were significantly associated with a 1.8-fold (odds ratio (OR) = 9.4, 95% confidence interval (CI) = 4.4-19.6, P < 0.001) increased risk for hypoadiponectinemia compared to individuals with the TT genotype of CDH 13 rs3865188 and normal waist circumference (WC) (OR = 5.1, 95% CI = 3.5-7.6, P < 0.001). However, in the joint effect of smoking and obesity, current smokers with the TT genotype of CDH13 rs3865188, as well as obesity, were significantly associated with a 6.2-fold (OR = 24.2, 95% CI = 3.0-196.6, P < 0.001) increased risk for hypoadiponectinemia compared to nonsmokers with the TT genotype of CDH 13 rs3865188 with normal WC (OR = 3.9, 95% CI = 1.7-9.3, P < 0.001). This study suggested that the association between CDH13 and adiponectin can be modified by lifestyle factors, such as smoking and obesity, among Korean men.

Adiponectin and smoking status: a systematic review

AIM

Smoking and adiponectin are individually associated with cardiometabolic pathologies. The present systematic review was carried out in order to summarize the association between the smoking status and circulating adiponectin levels.

METHODS

Original articles, restricted to epidemiological studies (by a cross-sectional, case-control and cohort study design) and intervention studies for adult humans, were screened for the years 1995-2010. All of the research group members then selected the eligible literature and assessed the articles in a structured systematic review manner.

RESULTS

There were 11 key studies, which included 9 articles with a cross-sectional design and 2 articles with an intervention design. Most cross-sectional studies reported lower levels of adiponectin in current smokers than in non/never smokers and/or ex-smokers, while 2 studies reported a non-significant difference in adiponectin between male smokers and non-smokers. The two intervention studies, conducted in patients on 9-week bupropion treatment and 6-month non-pharmacological treatment, reported that smoking cessation increased the adiponectin levels.

CONCLUSION

This review suggests that there is a decreased adiponectin level in current smokers and this reduction can be reversed by quitting smoking. More studies are required to confirm the findings and elucidate the biological mechanisms underlying the association between the smoking status and adiponectin levels.

Cigarette smoking and serum bilirubin subtypes in healthy Korean men: the Korea Medical Institute study

OBJECTIVES

Cigarette smoking is a modifiable risk factor for cardiovascular disease. Bilirubin is a potent antioxidant and its concentration decreases in smokers. However, studies about the association between cigarette smoking and bilirubin are scarce and most are limited to total bilirubin. Additionally, bilirubin is highly related to hemoglobin. Therefore, this study evaluates the association between bilirubin subtypes and cigarette smoking in healthy Korean men independently of hemoglobin.

METHODS

This study included 48 040 Korean men aged 30 to 87 years who visited the Korea Medical Institute for routine health examinations from January to December, 2007. The association of smoking with total, direct, and indirect bilirubin was assessed by logistic regression analysis taking into consideration differences in subjects and smoking characteristics.

RESULTS

Current smokers had lower bilirubin concentrations than never-smokers and ex-smokers. Smoking amount and duration were inversely significantly associated with total, direct, and indirect bilirubin. In a multivariable adjusted model, compared to never-smokers, the odds ratios (ORs) and 95% confidence intervals (CIs) of current smokers with the highest number of pack-years were 1.7 (1.6 to 1.9) for total, 1.5 (1.4 to 1.6) for direct, and 1.7 (1.6 to 1.9) for indirect bilirubin. After further adjustment for hemoglobin, this association became stronger (OR [95% CI], 2.1 [1.9 to 2.2] for total; 1.9 [1.8 to 2.0] for direct; 2.0 [1.9 to 2.2] for indirect bilirubin).

CONCLUSIONS

In this study, bilirubin subtypes are inversely associated with smoking status, smoking amount, and smoking duration in healthy Korean men independently of hemoglobin. Further studies are needed to investigate this association in healthy Korean women.

Influence of smoking and body weight on adipokines in middle aged women

Objective

Quitting smoking was associated with an undesirable weight gain. Both, cigarette smoking and obesity were accompanied by subclinical systemic inflammation. This may cause unfavourable changes in (plasma) adipokine concentration. The aim of the present study was to establish the influence of moderate cigarette smoking on the concentration of the adipokines leptin and adiponectin and the pro-inflammatory factors CRP, SAA, IL-6 and TNF-α in non-obese (n = 138) and obese (n = 175) perimenopausal women of the DRECAN-2005 survey.

Results

Among non-obese women, adiponectin was significantly lower in smokers than in non-smokers (16.88 ± 6.85 vs. 20.63 ± 10.04 μg/ml; P < 0.05). Leptin tended to lower values, too. Among obese women, none significant differences in adiponectin or leptin concentration were observed between smokers and non-smokers. In obese smokers and obese non-smokers, the adiponectin concentrations were significantly lower and the leptin concentrations were significantly higher than in non-obese non-smokers. Non-obese smokers showed significantly higher leukocyte count (6.50 ± 1.83 vs. 5.51 ± 1.31 GPT/l; P < 0.001) and serum amyloid A concentration (7.81 ± 1.25 vs. 4.22 ± 1.43 mg/l; P < 0.05) than non-obese non-smokers. There were only tendencies to higher concentration of CRP, IL-6, and TNF-α. In obese women, moderate cigarette smoking was not associated with higher leukocyte count or concentration of SAA. Among non-smokers, overweight was associated higher concentration of leptin (22.16 ± 12.16 vs. 11.49 ± 6.37 ng/ml; P < 0.001) and with significantly lower concentration of adiponectin (16.29 ± 8.01 vs. 20.77 ± 9.99 μg/ml; P < 0.001). Among smokers, overweight was associated with higher leptin concentration only (obese: 18.62 ± 13.46 vs. non-obese: 8.84 ± 4.92 ng/ml; P < 0.01).

Conclusions

In non-obese middle aged women, even moderate cigarette smoking adversely influences the serum concentration of adiponectin and SAA. Over-weight hides possible effects of smoking on cytokines and adipokines.

Smoking status is associated with serum high molecular adiponectin levels in community-dwelling Japanese men

AIM

Serum high molecular weight (HMW) adiponectin improves insulin sensitivity, and a decreased level has been reported as a risk factor for the development of diabetes and coronary heart disease. This association may be further confounded by smoking, which is involved in the development of insulin resistance. The aim of this study was to determine whether smoking status is associated with serum HMW adiponectin levels in community-dwelling males.

METHODS

The cross-sectional study was carried out in 2002. Study participants without a clinical history of diabetes (724 men aged 60+/-14 (mean+/-standard deviation) (range, 20-89) years) were randomly recruited from a single community at an annual physical examination. They were classified into never-smokers, ex-smokers, light-smokers (<30 pack x year), and heavy-smokers (>or=30 pack x year).

RESULTS

Mean serum HMW adiponectin levels were significantly lower in the current smokers than in the never- and ex-smokers but showed no significant difference between the light and heavy-smokers. Multiple linear regression analyses revealed that smoking status was significantly associated with HMW adiponectin levels, as were age, BMI, alcohol consumption, triglycerides, and high-density lipoprotein cholesterol. Multivariate-adjusted mean serum HMW adiponectin levels were lowest in the heavy-smokers, and significantly decreased in heavy-smokers compared with never-smokers and ex-smokers of an age >or=60 years, BMI >or=22 kg/m(2), alcohol consumption >or=22.9 g of ethanol/day, and HOMA-IR >or=1.6.

CONCLUSION

Smoking status is associated with serum HMW adiponectin levels in community-dwelling Japanese men.

Smoking cessation increases serum adiponectin levels in an apparently healthy Greek population

BACKGROUND

Smoking has been associated with low serum levels of adiponectin, an adipocytokine with insulin-sensitizing, anti-inflammatory and anti-atherogenic properties. The objective of this study was to assess the early effect on adiponectin levels of smoking cessation supported by bupropion.

METHODS

Apparently healthy smokers of both sexes with no additional cardiovascular risk factors were administered 150mg sustained-release bupropion twice daily for 9 weeks. Quitters constituted the active group and non-quitters the control group. Sandwich enzyme-linked immunosorbent assays were employed for the measurement of serum adiponectin and cotinine, the latter used for validation of self-reported abstinence.

RESULTS

Among the 106 participants (mean age 44.5+/-11.3 years, 57 females, Brinkman index 512.2+/-98.4, basal adiponectin 7.2+/-1.5mg/L), 45 (42.5%) had quitted smoking at week 9. Quitters' post-cessation adiponectin levels were significantly increased (mean difference with baseline 1.9+/-0.8mg/L, 95% CI 1.2, 2.3; p<0.001), while non-quitters' adiponectin remained unaltered. A multiple regression model including female gender (standardized beta coefficient=0.480, p=0.002), age (0.355, p=0.003), body mass index (BMI) (-0.308, p=0.005), waist circumference (-0.276, p=0.008), smoking status (-0.255, p=0.010), and cotinine levels (-0.233, p=0.021) explained about two thirds of the variation in adiponectin levels (adjusted R(2)=0.656).

CONCLUSIONS

Serum adiponectin levels appear to increase considerably within 2 months after smoking cessation. This finding may provide further insight into the mechanisms related to the detrimental effects of smoking and the benefits of quitting.