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Abnormal Serum Lipid Profile and Smoking are Associated with Plaque-type Psoriasi: A Case Control Study



Monireh Halimi, Behrooz Shokouhi and Amir Hagigi
 
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ABSTRACT

Psoriasis is a very commonly seen inflammatory condition in skin clinics. It has been suggested that this disease is associated with metabolic disease, particularly abnormalities in serum lipid profile. This study sought to examine possible association between plaque-type psoriasis and some individual variables of metabolic syndrome. After being approved by an ethical committee, 53 patients with plaque-type psoriasis were recruited along with 55 age and sex-matched healthy individuals as controls. The status of smoking, alcohol consumption and lipid profile including abnormally increases serum total cholesterol, Low Density Lipoprotein (LDL) and triglyceride, hypertension, diabetes mellitus and overweight/obesity were compared between the two groups. The case group was consisted of 27 males and 26 females with a mean age of 47.89±8.09 years. The controls were 35 males and 20 females with a mean age of 48.38±7.46 years. Smoking (43.4 vs. 20%, p = 0.01), increased serum total cholesterol (43.4 vs. 14.5%, p = 0.001), increased serum LDL (34 vs. 12.7%, p = 0.01) and hypertriglyceridemia (43.4 vs. 12.7%, p<0.001) were significantly higher in patients than in controls. These differences remained significant after logistic regression analysis. The two groups were comparable in terms of age (p = 0.74), sex (p = 0.18), alcohol consumption (p = 0.56), overweight/obesity (p = 0.74), hypertension (p = 0.33) and diabetes mellitus (p = 0.60). In conclusion, this study showed a significant association between smoking and abnormal lipid profile with psoriasis. Screening/preventive programs are recommended in this regard.

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  How to cite this article:

Monireh Halimi, Behrooz Shokouhi and Amir Hagigi, 2014. Abnormal Serum Lipid Profile and Smoking are Associated with Plaque-type Psoriasi: A Case Control Study. Journal of Medical Sciences, 14: 217-222.

DOI: 10.3923/jms.2014.217.222

URL: https://scialert.net/abstract/?doi=jms.2014.217.222
 
Received: March 20, 2014; Accepted: June 03, 2014; Published: August 11, 2014



INTRODUCTION

Psoriasis is a common skin disease all over the world, with an estimated prevalence of 1-3% among general population (Langley et al., 2005; Amirnia et al., 2012; El-Gayyar et al., 2012).

This disorder is generally believed to be an inflammatory disease, in which Th1/Th17 cells and pro-inflammatory cytokines are thought to play a pivotal role (Ghoreschi et al., 2007; Dhama et al., 2013; Sabeti et al., 2013).

Metabolic syndrome, on the other hand, is a very common condition comprising a cluster of interrelated entities such as overweight and obesity, insulin resistance and glucose intolerance, abnormal serum lipid profile, increased blood pressure, etc (Moller and Kaufman, 2005; Mahajan et al., 2010; Navali et al., 2011; Mori et al., 2013).

Although, a possible association between psoriasis and metabolic syndrome is not a new concept, this connection is still a matter of hot debate in current literature (Sommer et al., 2006; Gisondi et al., 2007; Al-Mutairi et al., 2010; Choi et al., 2010; Nisa and Qazi, 2010; Love et al., 2011; Mebazaa et al., 2011; Langan et al., 2012; Madanagobalane and Anandan, 2012; Zindanci et al., 2012).

Those who believe a significant connection between the two entities explain it by the chronic inflammation that is prevalently found in psoriatic patients, because many major individual components of metabolic syndrome such as insulin resistance and abnormal lipid profile are supposed to be mediated through inflammatory cytokines namely IL-1, IL-6 and tumor necrosis factor-α (Azfar and Gelfand, 2008).

Despite abundant, albeit conflicting reports regarding a possible association between psoriasis and metabolic syndrome, the role of individual components of the latter condition in association with psoriasis has been less investigated (Damevska et al., 2013). This study aimed to examine possible interrelation between some of these individual components, particularly lipid profile and psoriasis in a well-designed case-control setting.

MATERIALS AND METHODS

After being approved by the ethics committee of a local university, a total of 53 patients with definite diagnosis of plaque-type psoriasis and 55 age and sex-matched normal subjects from the same geographic region, were enrolled in this prospective, case-control study from February 2013 through to May 2014 in a referral clinic.

Cases with previous coronary, liver or renal disease, hypothyroidism or familial dyslipidemia or other autoimmune disease rather than psoriasis and those with a recent history (for at least 1 month before enrolment) of taking medications effective against serum lipids or immunosuppressive agents were not included. Written informed consents were obtained from participants.

After overnight fasting, venous samples were obtained and laboratory tests including the measurement of serum glucose, total cholesterol, Low Density Lipoprotein (LDL) and triglyceride were performed using standard photometric quantitative methods.

An increased serum level of cholesterol was defined when it was over 200 mg dL-1, an increased serum level of LDL was defined when it was over 160 mg dL-1 and an increased serum level of triglyceride was defined when it was over 150 mg dL-1 (Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults, 2001).

Overweigh/obesity was defined as having a Body Mass Index (BMI) = 25 (Damevska et al., 2013).

Study variables including demographic data (age and sex), history of smoking and alcohol consumption, overweight/obesity, history of hypertension, history of diabetes mellitus and the status of lipid profile were documented and compared between the case and control groups.

Statistical analysis: The SPSS software version 19.0 (IBM Corporation, New York, USA) was used for statistical analysis. Normal distribution of numerical data was ensured using Kolmogorov-Smirnov test and QQ plots. Independent samples t test or chi-square test were used for comparisons, where appropriate. Logistic regression analysis was used for determining independency of variables (Fattahi et al., 2011). A significance level of p≤0.05 was used.

RESULTS

A total of 53 patients with plaque-type psoriasis were included. The mean duration of the disease was 7.04±3.74 years (range: 1-19). The patients were 27 males (50.9%) and 26 females (49.1%) with a mean age of 47.89±8.09 years (range: 34-67) at the time of recruitment. Their normal counterparts (controls) were 55 subjects including 35 males (63.6%) and 20 females (36.4%) with a mean age of 48.38±7.46 years (range: 35-67).

Study variables are compared between the two groups in Table 1.

Table 1: Study variables in patients with psoriasis and controls
Image for - Abnormal Serum Lipid Profile and Smoking are Associated with Plaque-type Psoriasi: A Case Control Study
CI: Confidence interval, LDL: Low density lipoprotein, OR: Odds ratio, Data is shown as Mean±SD (for age) or number (%), *p<0.05 is significant

Accordingly, the two groups were comparable in terms of demographics (p = 0.74 for age and 0.18 for sex), alcohol consumption (p = 0.56), overweight/obesity (p = 0.74), hypertension (p = 0.33) and diabetes mellitus (p = 0.36).

In contrast, smoking was significantly more frequent among patients (43.4 vs. 20%; p = 0.01). Regarding serum lipid profile, increased serum cholesterol (43.4 vs. 14.5%; p = 0.001), increased serum LDL (34 vs. 12.7%; p = 0.01) and increase serum triglyceride (43.4 vs. 12.7%; p<0.001) were all significantly more common in the group of patients.

Based on the result of logistic regression analysis, smoking (p = 0.03), increased serum cholesterol (p = 0.01), increased serum LDL (p = 0.02) and increased serum triglyceride (p=0.02) were all independently higher in patients than in controls.

DISCUSSION

Among the studied variables in the present study, only smoking and abnormalities in serum lipid profile were associated with psoriasis. This association was independent of other variables such as age, sex, hypertension, diabetes mellitus, alcohol use or overweight/obesity, as well as medication profile used by the patients.

In a very recent study, a significant association was found between hypertriglyceridemia and psoriasis (Ali et al., 2014).

Similar significant association was also reported in an older study by Seishima et al. (1994).

In line with this reports, there was a significant and independent association between increased level of serum triglyceride and psoriasis in the present study. This association was the strongest one among other parameters (odds ratio = 5.26).

Beside serum triglyceride, we also found significant and independent associations between abnormal serum total cholesterol and LDL levels with psoriasis (odds ratios = 4.55 and 3.57, respectively).

This is in conformity with the results of a very recent study by Sarvtin et al. (2014) who studied 50 plaque-type psoriasis patients and 50 controls and reported higher levels of serum total cholesterol and LDL in patients. The association between serum increase cholesterol and psoriasis has been suggested by other investigators, too (Pietrzak et al., 2000).

It has been shown that the concentration of cholesterol in psoriatic crusts is higher than that in crusts normal skin shed. As a result, due to high loss of cholesterol during active phase of the disease a compensatory increase in cholesterol synthesis occurs and the level of serum cholesterol elevates (Lea et al., 1958).

It should be born in mind that there are also reports in the literature that have denied any connection between lipid abnormalities and psoriasis (Chen et al., 2008; Wakkee et al., 2010; Kim et al., 2012; Jensen et al., 2013). Apart from mythological errors and selection bias exist in many such studies (Damevska et al., 2013), some factors may justify this heterogeneity. Overall, three major parameters have been implicated in unfavorable cardiovascular role of psoriasis in affected patients: inflammation, lifestyle and medications (Wakkee et al., 2007). Difference in dietary habits among various nations is one of these justifications. In addition, it has been suggested that drugs routinely used in psoriasis such as methotrexate, cyclosporine and acitretin may inversely affect lipid profile (Naldi and Griffiths, 2005; Baharivand et al., 2013).

To eliminate this possible effect in the present study, all such systemic drugs were disconnected at least for one month prior to enrollment. In addition to an abnormal serum lipid profile, smoking was found to be another independent parameter in association with psoriasis in the present study.

It has been suggested that smoking might be a risk factor for psoriasis. It is believed that the number of cigarettes per day is a more important determiner in this regard than the duration of smoking itself. In addition to a causative role, some investigators have shown that smoking is against amelioration and response to treatment in psoriatic patients (Herron et al., 2005).

Although, the exact mechanism(s) underlying the etiologic/exacerbating role of smoking in psoriasis is unknown, it has been suggested the nicotine may augment inflammation, exists in such cases (Gelfand et al., 2006; Jensen et al., 2013).

The authors did not find a significant association of overweight/obesity, hypertension and diabetes mellitus with psoriasis. These findings are in line with some previous reports. For example, Ali et al. (2014) not only found a connection between psoriasis and diabetes mellitus in their case-control setting but also reported a protective effect for diabetes mellitus against the disease. This finding was confirmed by another study, too (Kim et al., 2012).

Likewise, some authors have concluded that body mass index is not a significant predictor of psoriasis in their study Herron et al. (2005), Griffiths and Barker (2007) and Kim et al. (2012) a finding that was also confirmed in the present study.

In this study, the two case and control groups were matched for age and sex. So, to evaluate the effect of demographic parameters further unmatched studies should be performed in future (Babaeinejad et al., 2011; Khodaeiani et al., 2012, 2013; Babaeinejad and Fouladi, 2013).

In conclusion, this study showed that lipid profile is abnormal among psoriatic patients. Since the increased serum levels of cholesterol and triglyceride is well-known risk factors for cardiovascular disease (Shakeri et al., 2011a, b; Tarzamni et al., 2012), it merits recommending that all patients with psoriasis need regular follow-ups and appropriate treatments if needed. In addition, smoking may play an independent role in the pathogenesis of psoriasis and thus the patients need to be encouraged to cease smoking.

CONCLUSION

Both smoking and abnormal lipid profile are associated with plaque-type psoriasis.

REFERENCES

  1. Al-Mutairi, N., S. Al-Farag, A. Al-Mutairi and M. Al-Shiltawy, 2010. Comorbidities associated with psoriasis: An experience from the middle east. J. Dermatol., 37: 146-155.
    CrossRef  |  PubMed  |  Direct Link  |  


  2. Ali, N.M., M. Kuruvila and B. Unnikrishnan, 2014. Psoriasis and metabolic syndrome: A case control study. Indian J. Dermatol. Venereol. Leprol., 80: 255-256.
    PubMed  |  Direct Link  |  


  3. Amirnia, M., E. Khodaeiani, R.F. Fouladi and A. Hashemi, 2012. Topical steroids versus PUVA therapy in moderate plaque psoriasis: A clinical trial along with cost analysis. J. Dermatol. Treat., 23: 109-111.
    CrossRef  |  Direct Link  |  


  4. Mori, N., H. Takemitsu, Y. Okada, I. Yamamoto and T. Arai, 2013. A comparison of metabolic parameters between obese and non-obese healthy domestic dogs in japan. Asian J. Anim. Vet. Adv., 8: 863-873.
    CrossRef  |  Direct Link  |  


  5. Azfar, R.S. and J.M. Gelfand, 2008. Psoriasis and metabolic disease: Epidemiology and pathophysiology. Curr. Opin. Rheumatol., 20: 416-422.
    CrossRef  |  Direct Link  |  


  6. Babaeinejad, S., E. Khodaeiani and R.F. Fouladi, 2011. Comparison of therapeutic effects of oral doxycycline and azithromycin in patients with moderate acne vulgaris: What is the role of age? J. Dermatol. Treat., 22: 206-210.
    CrossRef  |  PubMed  |  Direct Link  |  


  7. Babaeinejad, S.H. and R.F. Fouladi, 2013. The efficacy, safety and tolerability of adapalene versus benzoyl peroxide in the treatment of mild acne vulgaris: A randomized trial. J. Drugs Dermatol., 12: 1033-1038.
    PubMed  |  Direct Link  |  


  8. Baharivand, N., A. Mahdavifard and R.F. Fouladi, 2013. Intravitreal clindamycin plus dexamethasone versus classic oral therapy in toxoplasmic retinochoroiditis: A prospective randomized clinical trial. Int. Ophthalmol., 33: 39-46.
    CrossRef  |  PubMed  |  Direct Link  |  


  9. Chen, Y.J., C.Y. Wu, J.L. Shen, S.Y. Chu, C.K. Chen, Y.T. Chang and C.M. Chen, 2008. Psoriasis independently associated with hyperleptinemia contributing to metabolic syndrome. Arch. Dermatol., 144: 1571-1575.
    CrossRef  |  PubMed  |  


  10. Choi, W.J., E.J. Park, I.H. Kwon, K.H. Kim and K.J. Kim, 2010. Association between psoriasis and cardiovascular risk factors in korean patients. Ann. Dermatol., 22: 300-306.
    CrossRef  |  


  11. Damevska, K., L. Neloska, G. Gocev and M. Mihova, 2013. Metabolic syndrome in untreated patients with psoriasis: Case-control study. J. German Soc. Dermatol., 11: 1169-1175.
    CrossRef  |  PubMed  |  


  12. Dhama, K., S.K. Latheef, H.A. Samad, S. Chakrabort, R. Tiwari, A. Kumar and A. Rahal, 2013. Tumor necrosis factor as mediator of inflammatory diseases and its therapeutic targeting: A review. J. Med. Sci., 13: 226-235.
    CrossRef  |  Direct Link  |  


  13. El-Gayyar, M.A., A.A. El-Hawwary and N.I. Bakre, 2012. Evaluation of therapeutic effects of aloe vera: Coal tar mixture in psoriasis: An immunohistochemical study. Asian J. Dermatol., 4: 16-28.
    CrossRef  |  Direct Link  |  


  14. Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults, 2001. Executive summary of the third report of the National Cholesterol Education Program (NCEP) expert panel on detection, evaluation and treatment of high blood cholesterol in adults (Adult Treatment Panel III). J. Am. Med. Assoc., 285: 2486-2497.
    CrossRef  |  PubMed  |  Direct Link  |  


  15. Fattahi, E., M.H. Somi, M.R. Moosapour and R.F. Fouladi, 2011. Independent predictors of in-hospital re-bleeding, need of operation and mortality in acute upper gastrointestinal bleeding. Pak. J. Biol. Sci., 14: 849-853.
    CrossRef  |  PubMed  |  Direct Link  |  


  16. Gelfand, J.M., A.L. Neimann, D.B. Shin, X. Wang, D.J. Margolis and A.B. Troxel, 2006. Risk of myocardial infarction in patients with psoriasis. J. Am. Med. Assoc., 296: 1735-1741.
    CrossRef  |  PubMed  |  Direct Link  |  


  17. Ghoreschi, K., C. Weigert and M. Rocken, 2007. Immunopathogenesis and role of t cells in psoriasis. Clin. Dermatol., 25: 574-580.
    CrossRef  |  Direct Link  |  


  18. Gisondi, P., G. Tessari, A. Conti, S. Piaserico and S. Schianchi et al., 2007. Prevalence of metabolic syndrome in patients with psoriasis: A hospital-based case-control study. Br. J. Dermatol., 157: 68-73.
    CrossRef  |  


  19. Griffiths, C.E. and J.N. Barker, 2007. Pathogenesis and clinical features of psoriasis. Lancet, 370: 263-271.
    CrossRef  |  


  20. Herron, M.D., M. Hinckley, M.S. Hoffman, J. Papenfuss, C.B. Hansen, K.P. Callis and G.G. Krueger, 2005. Impact of obesity and smoking on psoriasis presentation and management. Arch. Dermatol., 141: 1527-1534.
    CrossRef  |  PubMed  |  


  21. Jensen, P., J.P. Thyssen, C. Zachariae, P.R. Hansen, A. Linneberg and L. Skov, 2013. Cardiovascular risk factors in subjects with psoriasis: A cross-sectional general population study. Int. J. Dermatol., 52: 681-683.
    CrossRef  |  


  22. Khodaeiani, E., R.F. Fouladi, M. Amirnia, M. Saeidi and E.R. Karimi, 2013. Topical 4% nicotinamide vs. 1% clindamycin in moderate inflammatory acne vulgaris. Int. J. Dermatol., 52: 999-1004.
    CrossRef  |  PubMed  |  Direct Link  |  


  23. Khodaeiani, E., R.F Fouladi, N. Yousefi, M. Amirnia, S. Babaeinejad and J. Shokri, 2012. Efficacy of 2% metronidazole gel in moderate acne vulgaris. Indian J. Dermatol., 57: 279-281.
    CrossRef  |  PubMed  |  Direct Link  |  


  24. Kim, G.W., H.J. Park, H.S. Kim, S.H. Kim and H.C. Ko et al., 2012. Analysis of cardiovascular risk factors and metabolic syndrome in korean patients with psoriasis. Ann. Dermatol., 24: 11-15.
    CrossRef  |  


  25. Langan, S.M., N.M. Seminara, D.B. Shin, A.B. Troxel and S.E. Kimmel et al., 2012. Prevalence of metabolic syndrome in patients with psoriasis: A population-based study in the united kingdom. J. Invest. Dermatol., 132: 556-562.
    CrossRef  |  


  26. Langley, R.G.B., G.G. Krueger and C.E.M. Griffiths, 2005. Psoriasis: Epidemiology, clinical features and quality of life. Ann. Rheumatic Dis., 64: ii18-ii23.
    CrossRef  |  


  27. Lea, Jr. W.A., H.H. Cornish and W.D. Block, 1958. Studies on serum lipids, proteins and lipoproteins in psoriasis. J. Invest. Dermatol., 30: 181-185.
    CrossRef  |  PubMed  |  Direct Link  |  


  28. Love, T.J., A.A. Qureshi, E.W. Karlson, J.M. Gelfand and H.K. Choi, 2011. Prevalence of the metabolic syndrome in psoriasis: Results from the national health and nutrition examination survey, 2003-2006. Arch. Dermatol., 147: 419-424.
    CrossRef  |  


  29. Madanagobalane, S. and S. Anandan, 2012. Prevalence of metabolic syndrome in south indian patients with psoriasis vulgaris and the relation between disease severity and metabolic syndrome: A hospital-based case-control study. Indian J. Dermatol., 57: 353-357.
    CrossRef  |  


  30. Mahajan, R., K. Gupta and V. Kapoor, 2010. A systematic account of pathogenesis, diagnosis and pharmacotherapy of metabolic syndrome: Things we need to know. Int. J. Pharmacol., 6: 338-345.
    CrossRef  |  Direct Link  |  


  31. Mebazaa, A., M. El Asmi, W. Zidi, Y. Zayani and R.C. Rouhou et al., 2011. Metabolic syndrome in tunisian psoriatic patients: Prevalence and determinants. J. Eur. Acad. Dermatol. Venereol., 25: 705-709.
    CrossRef  |  


  32. Moller, D.E. and K.D. Kaufman, 2005. Metabolic syndrome: A clinical and molecular perspective. Ann. Rev. Med., 56: 45-62.
    CrossRef  |  Direct Link  |  


  33. Naldi, L. and C.E.M. Griffiths, 2005. Traditional therapies in the management of moderate to severe chronic plaque psoriasis: An assessment of the benefits and risks. Br. J. Dermatol., 152: 597-615.
    CrossRef  |  


  34. Navali, N., S. Pourabolghasem, R.F. Fouladi and M.A. Nikpour, 2011. Therapeutic effects of biguanide vs. statin in polycystic ovary syndrome: A randomized clinical trial. Pak. J. Biol. Sci., 14: 658-663.
    CrossRef  |  PubMed  |  Direct Link  |  


  35. Nisa, N. and M.A. Qazi, 2010. Prevalence of metabolic syndrome in patients with psoriasis. Indian J. Dermatol. Venereol. Leprol., 76: 662-665.
    CrossRef  |  


  36. Pietrzak, A., B. Lecewicz-Torun and A. Borzecki, 2000. Postheparin serum lipolytic activity in psoriatic males. Med. Sci. Monitor, 6: 729-734.
    PubMed  |  Direct Link  |  


  37. Sabeti, S., F. Malekzad, M. Ashayer, R.F. Fouladi, K.K. Hesari, M.P. Toutkaboni and S. Younespour, 2013. The rate and pattern of bcl-2 and cytokeratin 15 expression in trichoepithelioma and nodular basal cell carcinoma: A comparative study. Indian J. Dermatol., 58: 331-336.
    CrossRef  |  Direct Link  |  


  38. Seishima, M., M. Seishima, S. Mori and A. Noma, 1994. Serum lipid and apolipoprotein levels in patients with psoriasis. Br. J. Dermatol., 130: 738-742.
    CrossRef  |  PubMed  |  Direct Link  |  


  39. Shakeri, A., M. Abdi, H.T. Khosroshahi and R.F. Fouladi, 2011. Common carotid artery intima-media thickness and atherosclerotic plaques in carotid bulb in patients with chronic kidney disease on hemodialysis: A case-control study. Pak. J. Biol. Sci., 14: 844-848.
    CrossRef  |  PubMed  |  Direct Link  |  


  40. Shakeri, A., M.B. Bazzaz, A. Khabbazi and R.F. Fouladi, 2011. Common carotid intima-media thickness in patients with late rheumatoid arthritis: What is the role of gender? Pak. J. Biol. Sci., 14: 812-816.
    CrossRef  |  PubMed  |  Direct Link  |  


  41. Sommer, D.M., S. Jenisch, M. Suchan, E. Christophers and M. Weichenthal, 2006. Increased prevalence of the metabolic syndrome in patients with moderate to severe psoriasis. Arch. Dermatol. Res., 298: 321-328.
    CrossRef  |  


  42. Sarvtin, M.T., M.T. Hedayati, T. Shokohi and Z. HajHeydari, 2014. Serum lipids and lipoproteins in patients with psoriasis. Arch. Iran. Med., 17: 343-346.
    PubMed  |  Direct Link  |  


  43. Tarzamni, M.K., N. Eshraghi, R.F. Fouladi, A. Afrasiabi, M. Halimi and A. Azarvan, 2012. Atherosclerotic changes in common carotid artery, common femoral artery and ascending aorta/aortic arch in candidates for coronary artery bypass graft surgery. Angiology, 63: 622-629.
    CrossRef  |  PubMed  |  


  44. Wakkee, M., R.M. Herings and T. Nijsten, 2010. Psoriasis may not be an independent risk factor for acute ischemic heart disease hospitalizations: Results of a large population-based dutch cohort. J. Invest. Dermatol., 130: 962-967.
    CrossRef  |  


  45. Wakkee, M., H.B. Thio, E.P. Prens, E.J. Sijbrands and H.A. Neumann, 2007. Unfavorable cardiovascular risk profiles in untreated and treated psoriasis patients. Atherosclerosis, 190: 1-9.
    CrossRef  |  


  46. Zindanci, I., O. Albayrak, M. Kavala, E. Kocaturk, B. Can, S. Sudogan and M. Koc, 2012. Prevalence of metabolic syndrome in patients with psoriasis. Scient. World J.
    CrossRef  |  Direct Link  |  


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