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Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. References

The association between alcohol consumption and psoriasis has been frequently discussed since the 1980s, but no systematic review has been elaborated on the subject so far.

The aim of this systematic literature review was to assess whether alcohol consumption is more prevalent in psoriasis patients than in the general population and whether alcohol consumption is a risk factor of psoriasis.

A systematic literature search was carried out in the Medline, Embase and Cochrane databases using the keywords ‘psoriasis’ AND ‘alcohol drinking’ OR ‘alcohol-related disorders’. The search was then enlarged with the keywords ‘psoriasis’ AND ‘risk factor’ OR ‘comorbidity’.

Altogether 911 references in English and French were found. Out of these, 837 articles were excluded by reading the abstract and 46 by reading the article. A total of 28 articles were selected. Alcohol consumption in psoriasis patients versus the general population: 23 studies were selected; 18 concluded that alcohol consumption was more prevalent in psoriasis patients, and 5 did not. Three studies compared the prevalence of excessive drinking using a questionnaire on alcohol dependence (CAGE or Self-administered alcohol screening test (SAAST)) or with quantitative criteria for excessive drinking. In these studies, excessive drinking was more prevalent among psoriasis patients than in the general population. Other articles studied the quantity and type of alcohol consumed. In 11 studies, psoriasis patients consumed more alcohol than the controls. Four other studies showed excessive alcohol consumption in psoriasis patients without control group comparison. Conversely, five studies identified no difference in alcohol consumption between psoriasis patients and the general population. The heterogeneity in the measurement of alcohol consumption did not allow performing meta-analysis. Alcohol as a risk factor for psoriasis: only five studies were selected. In four of these studies alcohol was found to be a risk factor for psoriasis.

Alcohol consumption seems to be greater in psoriasis patients than in the general population. However, there is not enough evidence to establish whether alcohol consumption is indeed a risk factor for psoriasis.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. References

Psoriasis is a common disease affecting approximately 2%–3% of the population worldwide. Genetic and environmental factors are believed to play an etiological role in the disease. Environmental factors considered include stress, chronic skin trauma, infections, drugs, alcohol consumption and smoking. However, the role of each factor needs to be clarified.

In the 1980s, alcohol and psoriasis were often linked and initial studies suggested excessive alcohol consumption in psoriasis patients. Some studies showing conflicting results were subsequently published.

The aim of this systematic analysis of the literature was to answer two questions: (i) Are psoriasis patients higher alcohol users than the general population? (ii) Is alcohol a risk factor for psoriasis? We performed a systematic literature review (SLR) to prepare for the generation of evidence-based recommendations on alcohol consumption. The reviewing process leading to these recommendations is described in detail in the same issue of the journal.[1]

Methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. References

Two of the authors (EB, LM) conducted a systematic review of all studies investigating the relationship between alcohol and psoriasis published between 1974 and December 2011. The Cochrane, Embase and Medline databases were systematically searched using a combination of Medical Subject Headings (Mesh): ‘psoriasis’ (Majr) OR ‘arthritis psoriatic’ (Majr) AND ‘alcohol-related disorders’ (Majr) OR ‘alcohol drinking’ (Majr). To extend this first search, a second search was conducted using the following Mesh: ‘psoriasis’ AND ‘risk factor’ OR ‘comorbidity’. The bibliographical search was limited to English and French articles on humans. All the references obtained in those three databases were then screened. Relevant studies were initially selected by reviewing the title and abstract. With regard to the remaining studies, the full article was read. Final consensus was reached through discussions within the panel of experts.

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. References

In the first search, we identified a total of 254 eligible articles by searching the Medline, Cochrane and Embase databases. Of these 254, 211 were eliminated by reading title or abstract and 21 by reading the article. A total of 22 articles were selected. The detailed flowchart describing both the selection process and the reasons for exclusion is displayed in Fig. 1.

image

Figure 1. Flowchart of study selection process.

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In the second search (‘comorbidity’ OR ‘risk factor’), we identified a total of 657 eligible articles by searching the Medline database. Of these 657, 626 were eliminated by reading the title or abstract and 25 after reading the article. In all, six articles were selected. The detailed flowchart is shown in Fig. 2.

image

Figure 2. Second flowchart of study selection process.

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A total of 28 articles were finally selected through two searches to answer the two questions.

Have psoriasis patients a higher alcohol consumption than the general population?

Of the 28 articles retrieved, 23 were selected in response to this question. 18 studies[2-19] concluded that alcohol consumption was higher in psoriasis patients than in the general population, and five studies[20-24] concluded that this was not the case.

Three case–control studies[2-4] compared the prevalence of excessive drinking using questionnaires on alcohol dependence: CAGE (four questions: Have you ever felt you should Cut down your drinking? Have people Annoyed you by criticising your drinking? Have you ever felt bad or Guilty about your drinking? Have you ever felt you needed a drink first thing in the morning (Eye-opener) to steady your nerves or to get rid of a hangover?) or Self-administered alcohol screening test (SAAST) questionnaires, or recommended criteria for excessive drinking behaviour (>21 units per week for men, >14 units per week for women). In these studies, excessive drinking was more frequent among psoriasis patients than in the general population (Table 1). Higgins et al.[3] showed that the OR (odds ratio) for an alcohol consumption above 50 units per week was 8.01 (3.62–17.7) in psoriasis.

Table 1. Comparison of the prevalence of excessive drinkers among psoriasis patients and general population
Study (author and year of publication)DesignPatientsAlcohol consumptionMain results
Carmichael et al.[2]Case–control60 psoriasis62 controlsQuestionnaire on alcohol consumption, CAGE questionnaireAlcoholism psoriasis: 11/60 Controls: 7/62
Morse et al.[4]Case–control99 psoriasis99 controlsQuestionnaire SAASTTotal number of alcoholics: 11 psoriasis vs. 3 controls: borderline significance (0.05 <P <0.10)Men alcoholics: 10 psoriasis vs. 1 control (< 0.05)
Higgins et al.[3]Case–control130 psoriasis42 atopic dermatitis222 controlsAlcohol consumption >21 units per week in men and>14 units per week in womenAlcoholics: 28% psoriasis, 3.8% atopic dermatitis, 4% controlsConsumption ≥50 units per week: 19% psoriasis, 0% atopic dermatitis, 0.5% controls OR = 8.01 (95% CI 3.62–17.7)

Eleven articles[5-15] concluded that alcohol consumption was more prevalent in psoriasis patients than in the general population (Table 2). There were nine case–control studies[5-13] with OR for alcohol consumption ranging from 2 to 3, and two cross-sectional studies.[14, 15]

Table 2. Alcohol consumption is higher in psoriasis that in general population in eleven studies
Study (author and year of publication)DesignPatientsAlcohol consumptionMain results
Gruber et al.[5]Case–control150 psoriasis 150 controlsConsumption: every day, often, seldom, teetotallerAlcohol consumption: 60% psoriasis vs. 28.1% controls Daily consumption: 25.3% psoriasis vs. 0.7% controls
Zamboni et al.[6]Case–control219 psoriasis 747 controlsSemi-quantitative questionnaireMen psoriasis 72.6 vs. controls 55.4 (P significant) Women psoriasis 26.3 vs. controls 16.8 (P significant)
Poikolainen et al.[8]Case–control144 psoriasis 285 controlsSelf-administered questionnaireAlcohol consumption: 44.8 g psoriasis vs. 19.9 g controls (= 0.002) Frequency of alcohol intoxication: 57.9 psoriasis vs. 37.2 controls (P = 0.003) Alcohol intake of 100 g/day compared with no intake: OR = 2.2 (95% CI 1.3–3.9) For being intoxicated once a week compared with not at all: OR = 1.3 (95% CI 1.1–1.5)
Poikolainen et al.[7]Case–control55 psoriasis 108 controlsSelf-administered questionnaireAlcohol consumption: 9.3 g/d psoriasis vs. 3.9 g/d controls (P = 0.04) Frequency of alcohol intoxication: 19.4 psoriasis vs. 10.1 controls (P = 0.04) Alcohol intake of 20 g/d compared with no intake: OR = 2.2 (95% CI 1.1–4.2)
Sommer et al.[9]Case–control581 psoriasis 1044 controlsConsumption: none or low, moderate, regular, heavyNone vs. moderate: OR = 2.78 (95% CI 2.14–3.62) vs. regular: OR = 3.33 (95% CI 2.20–5.05) vs. heavy: OR = 3.61 (95%CI 1.85–7.07)
Wolk et al.[10]Case–control373 psoriasis 273 controlsNever, ≤1 per month, 2–4 per month, 2–3 per week, ≥4 per weekWomen: no positive association Men: 5–19 drinks per month: OR = 3.4 (95% CI 1.4–8.1) ≥20 drinks per month: OR = 3.1 (95% CI 1.4–7.2)
Jankovic et al.[11]Case–control110 psoriasis 200 controlsConsumption: yes or noUnivariate analysis: OR = 1.97 (95% CI 1.20–3.21) Multivariate analysis: OR = 2.55 (95% CI 1.26–5.17) (= 0.01)
Gerdes et al.[12]Case–control1131 psoriasis 7024 controlsConsumption < or >1 per dayTotal OR = 3.1 (95% CI 2.53–3.8), men OR = 2.86 (95%CI 2.29–3.56), women OR = 5.12 (95% CI 3.12–8.39) Multivariate logistic regression analysis: OR = 2.85 (95% CI 2.29–3.56)
Zhang et al.[13]Case–control789 psoriasis 789 controlsPositive drinking history: drinking ≥twice a dayPositive drinking history: Men cases 29.8% vs. controls 9.2%Women cases 8.6% vs. controls 1.4% Men OR = 4.17 (95% CI 2.79–6.23), Women OR = 6.6 (95% CI 2.4–19.62)
Chaput et al.[14]Cross-sectional1987 subjects (44 psoriasis)Quantity of alcohol daily drunk during the past 5 years10 of the 1348 non drinkers had psoriasis compared with 34 of the 639 drinkers The estimated relative risk of psoriasis associated with an alcohol consumption of over 50 g a day was 7.5 (3.5–16.4)
Braathen et al.[15]Cross-sectional10567 subjects (149 psoriasis)Questionnaire85.8% of psoriasis had consumed some alcohol during the last 12 months compared with 76.9% of the non-psoriasis (< 0.01)

Four articles[16-19] studied alcohol consumption or alcoholism in psoriasis patients without reference group comparison. In the MacAleer et al.[16] and Kirby et al.[17] studies, between 13% and 30% of psoriasis patients were considered to be alcoholic (percentage depending on questionnaire used to evaluate alcohol dependence: Michigan alcohol screening test (MAST) or CAGE questionnaires). In the study by Serwin et al.,[18] 20% of psoriasis patients were considered to be excessive drinkers. In the study by Gupta et al.,[19] 18.7% of psoriasis patients consumed more than 80 g alcohol per day. Although alcohol consumption appeared to be high in these studies, no conclusion can be drawn because of the lack of a control group.

In five articles[20-24], alcohol consumption among psoriasis patients was not higher than in the general population (Table 3).

Table 3. No difference in alcohol consumption in psoriasis compared to general population in five studies
Study (author and year of publication)DesignPatientsAlcohol consumptionMain results
Grunnet et al.[20]Case–control281 psoriasis 230 controlsQuestionnaire: none, <1 units per day, 1–3 units per day or > 3 units per dayNo difference could be observed between psoriasis and controls: Case: 0 per day: 9%, <1: 70%, 1–3: 13%, >3: 8% Controls: 0 per day: 8%, <1: 61%, 1–3: 19%, >3: 12%
Naldi et al.[24]Case–control560 psoriasis 690 controls<2 drinks per day, 2–4 drinks per day, ≥5 drinks per dayDrinks per day: <2 per day: OR = 0.9 (95% CI 0.7–1.3) 2–4 per day: OR = 1.2 (95% CI 0.9–1.8) ≥5 per day: OR = 1.4 (95% CI 0.8–2.2)
Naldi et al.[21]Case–control404 psoriasis 616 controlsQuestionnaire<1 drink per day: OR = 0.9 (95% CI 0.6–1.3) 2–4 drinks per day: OR = 1.3 (95% CI 0.91.8) >5 drinks per day: OR = 1.7 (95% CI 1.0–3.0) Logistic regression OR = 1.5 (95% CI 0.9–2.4) = non significant
Wolkenstein et al.[22]Case–control356 psoriasis 1068 controlsAlcohol consumption in the past weekAlcohol in the past week: case 65.3% vs. controls 59.6% Univariate analysis OR = 1.27 (95% CI 0.99–1.64) Multivariate analysis OR = 1.28 (95% CI 0.98–1.67)
Huerta et al.[23]Cohort study3994 psoriasis Data source: UK general practice research database0, 1–20 g/week, >20 g/week1–20 g/week: OR = 0.91 (95% CI 0.82–1.00), adjusted OR = 0.96 (95% CI 0.87–1.06) >20 g/week: OR 1.07 (95% CI 0.92–1.24) adjusted OR = 1.06 (95% CI 0.90–1.25)

The Forrest graph portraying global results is shown in Fig. 3. Alcohol consumption seems to be greater among psoriasis patients than in the general population. However, no meta-analysis could be carried out because of the heterogeneity of the results.

image

Figure 3. Alcohol consumption in psoriasis compared to general population.

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Is alcohol a risk factor for psoriasis?

Five of the 28 articles retrieved were selected in response to this question.[7, 8, 10, 11, 25]

Four studies concluded that alcohol was actually a risk factor for psoriasis. Indeed, for Jankovic et al.[11], the OR for psoriasis was 2.55 (95% CI 1.26–5.17) in alcohol users in multivariate analysis. In the Poikolainen et al.[8] study, the mean alcohol intake recalled before the onset of skin disease was 42.9 g/day among psoriasis patients and 21.0 g/day among the controls (P = 0.004). The mean annual frequency of alcohol intake was 61.6 in psoriasis patients and 42.6 in the controls (P = 0.007). Qureshi et al.[25] conducted a prospective study involving 82 869 female nurses who were followed up for 14 years. Compared with women who did not drink alcohol, the multivariate relative risk of psoriasis was 1.72 in drinkers (95% CI 1.15–2.57). Wolk et al.[10] observed a statistically significant association between alcohol consumption and psoriasis onset in men, but not in women. In men, the OR was 3.4 (95% CI 1.4–8.1) for 5–19 drinks per month and 3.1 (95% CI 1.4–7.2) for more than 20 drinks per month.

In one study (Poikolainen et al.[7]), alcohol consumption was not a risk factor for psoriasis in women. The mean alcohol intake recalled was 8.0 g/day in psoriasis patients and 4.7 g/day in controls, but this difference was not significant. The logistic regression analysis did not show any significant link between psoriasis and alcohol intake.

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. References

Most of the studies showed increased alcohol consumption in psoriasis patients compared to controls. However, there is limited evidence to establish whether alcohol addiction is more frequent in psoriasis patients than in the general population.

Between studies, considerable heterogeneity on alcohol consumption evaluation methods was observed. Some studies used an ‘alcohol consumption: yes or no’ criteria, whereas others reported on the amount and type of alcohol consumed using questionnaires. The alcohol quantity deemed to be significant also differed between studies: >1 drink per day, >3 drinks per day, etc. Moreover, some studies used specific validated criteria to diagnose alcoholism such as CAGE, MAST or SAAST questionnaires. Others used as cut-off values defined in the recommended guidelines for excessive alcohol consumption (>21 units per week for men, >14 units per week for women). This heterogeneity in the measurement of alcohol consumption made it impossible to perform meta-analysis.

In our literature review, four studies concluded that alcohol is a risk factor for psoriasis.[8, 10, 11, 25] A last one[7] did not, but this was probably because of small sample size giving low power to detect differences. Indeed, in this study focusing on women, alcohol consumption was very low overall and only a small number of subjects were included, whereas in a previous study with the same design focusing on men, a positive association was shown.[8]

Zhu et al.[26] recently published a meta-analysis of case–control studies on alcohol consumption and risk of psoriasis. The authors concluded that there is strong evidence of a positive correlation between alcohol consumption and the risk of psoriasis. In our opinion, this result should be tempered. Because most of the studies examined had no data on alcohol consumption before the onset of psoriasis, It can only be concluded that alcohol consumption is higher in psoriasis but not that it is a risk factor for psoriasis.

To determine whether alcohol is a risk factor for psoriasis, we selected five studies with data on alcohol consumption before the onset of psoriasis. Qureshi et al.[25] conducted a cohort study evaluating alcohol intake and cases of incident psoriasis. Others[7, 8, 11, 25] used case–control studies and asked patients to recall their mean alcohol intake before the onset of skin disease. There is therefore a potential recall or socially acceptable bias with the retrospective assessment of alcohol intake which prevents from drawing conclusion on the subject.

Conclusion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. References

In this systematic literature review (SLR), most of the studies conclude that alcohol consumption is higher in psoriasis patients than in the general population. However, it remains still unclear whether alcohol represents a genuine risk factor or is merely a consequence of psoriasis.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. References