The Relationship between Eating Styles and the Severity of Psoriasis: A Cross-Sectional Study in Thailand

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Introduction
Psoriasis possesses a multifaceted and intricate origin, representing a condition infuenced by multiple factors that is linked to a number of serious comorbidities such as metabolic syndrome, obesity, diabetes, and cardiovascular disease with shared chronic systemic infammation [1].Psoriasis is developed as a result of genetic susceptibility, environment, and lifestyle factors including nutritional factors.Obesity, drinking, smoking, sleep disturbance, and mental stress may exacerbate psoriasis.Nutrition can play a crucial role both in disease pathogenesis and severity.Lifestyle modifcation such as healthy eating, optimal exercise, adequate rest, maintain healthy weight, and limited use of tobacco and alcohol consumption can help improve psoriasis severity and comorbidities [2].Maintaining a healthy eating behavior has been emphasized as one of the behavioral modifcation.
One of the eating behavior aspect which correlates to weight gain and high calorie consumption is the eating style [3].Te eating styles are classifed into three categories including emotional, external, and restrained style.Emotional eating pertains to the consumption of excessive food in response to negative emotions, such as anxiety or irritability.Tis eating style is related to body weight fuctuation, binge eating, disruption of weight loss efort, and depression.Te external eating is a hypersensitive response to external food cues such as the sight or scent of appetizing food.Overeating and impulsivity are related to external eating styles.Restrained eating is characterized as an individual's conscious efort to limit food consumption as a means of controlling body weight.However, when cognition is disinhibited, restrained eaters are more likely to overeat, leading to weight gain [4].However, the association between eating styles and psoriasis remains uncertain.
Te objective of this study was to examine the association between three eating styles and the severity of psoriasis, while accounting for all potential confounding factors.

Materials and Methods
Tis study was performed among 158 patients with psoriasis from August to December 2021 at Vajira Hospital, Bangkok, Tailand.All patients, age of 18 years and older, with chronic plaque psoriasis confrmed by the dermatologist were included.Patients with other types of psoriasis such as pustular, erythrodermic, or guttate psoriasis were excluded.A verbal explanation of the study was given to all eligible participants and all participants were provided with a written informed consent at enrollment.Te Institutional Review Board of Navamindradhiraj University approved this study (approval number COA 026/2564).
Personal demographic and health-related characteristic questionnaires were designed.Te details of questionnaires included various aspects such as age, gender, smoking habits, alcohol consumption, daytime and nocturnal sleep duration, psoriasis duration, and treatment modalities.Nail and joint involvement were based on the patient's medical record and direct clinical examination.Nocturnal sleep duration was measured by the question "During the past month, how many hours of actual sleep did you get at night?" Nocturnal sleep was divided into three categories: short (<7 hours), moderate (7-9 hours), and long (>9 hours).Daytime sleep duration was measured by the question "During the past month, how long did you take a nap during the day?" Daytime sleep was divided into three groups: 0 hours, >0 minutes and ≤30 minutes, and >30 minutes [5].
Anthropometric measurements were taken with all subjects wearing light clothes without shoes.Height was measured by WB3007301 model of TANITA scale (Tanita Corp., Tokyo, Japan).Body mass index (BMI) was calculated as weight in kilograms divided by height in meters squared (kg/m 2 ).Te BMI was categorized into three groups based on BMI cut-off points: <25 kg/m 2 , 25-29.99 kg/m 2 (overweight), and ≥ 30 kg/m 2 (obesity) [6].Body composition analysis data were obtained from InBody720 model of bioelectrical impedance analyzer (InBody Co., Ltd, Seoul, Korea).Te patient voided and stood on the device after at least 8 to 12 hours of fasting.Te device captured body weight, age, height, and gender.Total body weight was the sum of fat mass and fat free mass.Body fat percentage calculated the percentage of fat mass within the total body weight.Obesity was defned as body fat percentage more than 25% in males and 35% in females [7].
Te clinical severity of psoriasis was determined by Psoriasis Area and Severity Index (PASI), which is a numerical score ranging from 0 to 72 as qualitative measurement of the average erythema, infltration, and desquamation of the lesions, weighted by the area of involvement.Severity of psoriasis was categorized into three groups.Mild disease severity was defned as the PASI score ≤6, the PASI score >6 and >10 were considered as moderate and severe disease, respectively [8].In addition, Tai-Eating Style Scale (T-ESS), Eating Attitudes Test-26 (EAT-26) Tai version, and Tai Stress test (TST) were evaluated.
T-ESS consisted of 31 items, 12 of which measure emotional eating style, 8 of which measure external eating and 11 of which measure restrained eating, all of which were rated on a fve-point Likert type scale (1 � Never, 2 � Seldom, 3 � Sometimes, 4 � Often, and 5 � Always).In this study, eating styles of each participant were categorized into three domains, with the highest subscale score indicating the greatest endorsement of each particular eating style [9].
EAT-26 was used for assessing eating disorders in the general population.Te EAT-26 consisted of 26 items asking about eating behavior characteristics rated on a six-point Likert type scale related to how often an individual behaves (Never, Rarely, Sometimes, Often, Usually, and Always).Items 1-25 were scored on a 4-point scale with (Others � 0, Often � 1, Usually � 2, and Always � 3).Item 26 was reverse scored and a fnal score was calculated by summing items 1-26.A cut-of score of 12 was indicative of eating disorder tendencies [10].
TST had 24 questions describing psychological reactions in both positive and negative feelings in relation to events occurring in daily life.Te TST rated on a three-point Likert type scale (0 � Never, 1 � Sometimes, and 3 � Often).Responses to questions assessing negative feelings (items 1-12) and positive feelings (items 13-24) were separately calculated then stress status was categorized using the matrix table.Te TST was divided into four categories: high stress status (scores 7-9), mild stress (scores 5-6), normal mental health (scores 2-4), and excellent mental health (score 1) [11].
Te quantitative variables were described as mean-± standard deviation (SD) or median and interquartile range (IQR).Te categorical variables were described as number and percentage.Te binary logistic regression model was used to calculate odds ratios (OR) and 95% confdence interval (CI) for comparison of eating styles and all potential confounding factors between psoriasis patients with mild disease and those with moderate to severe disease.Te crude associations were calculated frst and then the variables that showed statistically signifcant diferences between the groups were adjusted.All analyzes were performed using STATA statistical software version 13 (Stata Corp., College Station, TX, USA).Statistical signifcance was determined as P < 0.05.

Results
Of the 158 patients with chronic plaque psoriasis, the mean age ± SD was 53.6 ± 15.2 years and the median BMI was 25.7 kg/m 2 (IQR 23.0-29.3).Te median nocturnal sleep duration was 7 hours (IQR 6-8) and median daytime sleep duration was 0 hours (IQR 0-1).Te median PASI score was 3.7 (IQR 2.5-6.1) and median disease duration was Te univariate analysis revealed that patients with joint involvement were signifcantly associated with an increased risk of more severe psoriasis while the patients with nail involvement tended to increase the risk.Table 2 shows the factors associated with the severity of psoriasis.
Te univariate and multivariate correlations between eating styles and psoriasis severity are shown in Table 3. Patients who had predominant emotional eating had signifcantly more moderate to severe psoriasis (OR, 4.6; 95% CI, 1.86-11.24)compared with restrained eating.Te association remained signifcant with similar estimated efects after adjusting for joint involvement (adjusted OR, 3.9; 95% CI, 1.52-9.81).

Discussion
Tis study demonstrates that psoriasis patients with emotional eating style experience greater severity compared to other eating styles.After adjusting the signifcant associated factor, psoriasis patients with emotional eating style was 3.9 times more likely to exhibit greater psoriasis severity compared to those with restrained eating style.Meanwhile, psoriasis patients with external type eating showed nonsignifcant association with the more clinical severity compared to the restrained eating style.
Psoriasis is a chronic infammatory and immune mediated disease, caused by the interplay between various genetic and environmental factors.Sustained infammation leads to activation of keratinocyte proliferation and diferentiation including dysregulation of the immune system.Te results of the major infammatory cytokines, interferon alpha (IFN-α), IFN-c, tumor necrotic factor alpha (TNF-α), interleukin-1 (IL-1), IL-6, IL-17, IL-22, etc., increase the severity of disease and also cause other systemic associated comorbidities [12].Obesity, one of comorbid diseases, is associated with chronic infammation.Most of the obese patients have exceed body fat mass or adipose tissues.Tese adipose tissues secrete various proinfammatory mediators such as TNF-α, IL-1, and IL-6 and also numerous adipokines such as leptin, visfatin, and resistin [13].Te major roles of leptin are appetite controller and immune regulators.In obese patients, there is an increase in leptin level with altered proper functions called leptin resistant state.In this state, the increase in food intake and the more infammatory cytokines, TNF-α, IL-1, and IL-6, were demonstrated.Leptin can also induce the T-helper cells and neutrophils infltration into the skin causing psoriasis disease fare up [14].Te roles of visfatin and resistin were found to increase in innate and adaptive immune function, resulting in secretion of proinfammatory cytokines [15].
Individuals exhibiting emotional eating tendencies tend to gravitate towards consuming high-density foods and engage in eating as a response to negative emotions, such as sadness, Dermatologic Terapy anger, and disappointment [4].Emotion is one of the predictive factors of weight loss behaviors and impacts on food choices [16].As a multifactorial disease, psoriasis would be activated by both of mental stress and hyperpalatable diet with foods containing high saturated fats and sugars.Tere is a positive correlation between mental stress and the consumption of hyperpalatable diets and infammation [17].
However, this study shows no relation between psoriasis severity and stress status.Tere was a signifcant association between a hyperpalatable diet and obesity.Te consumption of a hyperpalatable diet was linked to both psoriasis disease activity and heightened levels of infammatory cytokines [18].Te systematic review showed positive association between hyperpalatable diet and the emotional eating styles [19].
Terefore, the proper eating style is very important to maintain good health especially in psoriasis patient.Tis study proved that emotional eating style is the worst eating style in psoriasis patient among three eating styles.Previous studies indicated that the rigid from of restrained eating type resulted in obesity more than the fexible eating style [20].Te external eating style was also associated with hyperpalatable diet [21].Terefore, people with either extreme styles may not necessarily exhibit the most favorable outcomes.Te emotional eating style and hyperpalatable food were the independent factors that have strongly linked to each other in psoriasis disease controlling.Consequently, the objective of treatment in both obesity and psoriasis is to efectively address and overcome overeating.Cultivating an optimal eating style may play a crucial role.In a recent study, it was observed that participants who reduced their emotional eating tendencies during weight loss programs achieved greater success in their weight loss eforts compared to those who experienced an increase in emotional eating [22].Future studies should focus on investigating therapeutic approaches aimed at enhancing the well-being of psoriasis patients with emotional eating styles.Potential methods to explore include mindfulness-based eating awareness training, cognitive-behavioral therapy, and the use of food records.Te limitations in this study were the lack of biologic markers and daily dietary records.Te generalizability of the fndings was restricted to chronic plaque-type psoriasis in Asians with mild-to-moderate severity and normal to overweight status.

Conclusions
Te present study highlighted the signifcant association between eating styles and disease severity in patients with chronic plaque-type psoriasis.Assessment of eating styles as a risk factor in psoriasis patients is essential.Future studies on eating styles in psoriasis patients could include average daily total calories consumption and its composition.Furthermore, integrating conventional nutritional guidance for dietary recommendations, alongside the assessment and guidance of eating styles, could be an integral part of diet education for patients dealing with psoriasis.

Table 1 :
Baseline clinical characteristics, eating styles, eating attitudes, and stress status of psoriasis patients (n � 158).

Table 2 :
Association between risk factors and clinical severity of psoriasis in 158 psoriasis patients.

Table 3 :
Association between eating styles and clinical severity of psoriasis in 158 psoriasis patients.