doi: 10.1111/1346-8138.13572
Journal of Dermatology 2016; : 1–6
ORIGINAL ARTICLE
Hidradenitis suppurativa is not associated with the metabolic syndrome based on body type: A cross-sectional study Allard R. J. V. VOSSEN,1 Hessel H. van der ZEE,1 Armanda J. ONDERDIJK,1 Jurr BOER,2 Errol P. PRENS1 1
Department of Dermatology, Erasmus University Medical Center, Rotterdam, 2Department of Dermatology, Deventer Hospital, Deventer, The Netherlands
ABSTRACT A body type with a high waist circumference or elevated waist-to-hip ratio (WHR), known as the “apple” body type, represents central/visceral obesity and is associated with the metabolic syndrome. The aim of this study was to simultaneously investigate the body mass index (BMI) and WHR in order to classify body types in individuals with hidradenitis suppurativa (HS) compared with a general dermatological population. A hospital-based cross-sectional study was performed in the Netherlands. One hundred and six HS patients and 212 controls were included. The BMI was significantly higher in the HS group in comparison with the control group, at 27.8 5.4 and 25.6 4.8, respectively (P < 0.001). The WHR did not significantly differ between HS patients and the control dermatological population (P > 0.05). A more peripheral pattern of bodyweight distribution was seen in 43% of the 37 obese HS individuals, in contrast to 19% of 31 obese patients in the control group (P = 0.036). In conclusion, the body type in obese HS patients, based on the WHR, shows a more peripheral pattern and differs from the WHR in the BMI-matched general dermatological population.
Key words:
acne inversa, body mass index, mechanical stress, metabolic syndrome, waist-to-hip ratio.
INTRODUCTION Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic, recurrent, inflammatory skin disease. The disease mostly develops after puberty and is characterized by painful, inflammatory nodules and abscesses mainly located at the axillary, inguinal and anogenital regions.1,2 The disease is common, with an estimated prevalence rate between 0.05% and 4%, with a female-to-male ratio of 3:1.1,3,4 The pathogenesis of HS is still not fully understood; infundibular hyperkeratosis, with follicular occlusion is thought to be the primary event, followed by rupture with a foreign body type inflammatory response.1,5 HS has been linked to a variety of concomitant and secondary diseases, such as inflammatory bowel disease, spondyloarthropathy and squamous cell carcinoma.1,6 There is strong evidence that HS is associated with a high body mass index (BMI).1,7 Obesity in HS ranges 12–88%, depending on the type of population,8 with a positive correlation existing between BMI and disease severity.9,10 However, not all HS patients are obese, and non-obese HS individuals may reflect a HS subtype on its own.7 Besides obesity affecting health status, body shape and proportion may be important in relation to health risks.11 The general body stature is
primarily determined by the configuration of the skeletal structure and muscles (the fat-free mass), but also the distribution of fat. BMI represents a rough estimate of shape, whereas waist circumference and waist-to-hip ratio (WHR) give a more accurate implication of relative abdominal shape. Central or visceral type adiposity is considered as an additional indicator of health, and a risk of developing serious health conditions.12 In line with this, the WHR seems to be a valid predictor of the metabolic syndrome. The metabolic syndrome is a multifaceted disorder and comprises obesity, dyslipidemia and hyperglycemia. Individuals who have the metabolic syndrome typically have apple-shaped bodies, meaning they have larger waists and carry most weight around their abdomen (Fig. 1). Abdominal adiposity measured by an elevated WHR is associated with visceral fat accumulation and an adverse metabolic profile.13,14 It is accepted that having a pear-shaped body, namely, carrying more of your weight around the hips and having a narrower waist with most body fat deposited subcutaneously, puts a person at a lower risk of developing diabetes, heart disease and other complications of the metabolic syndrome.13,15 In general, immune-mediated inflammatory diseases including several skin disorders such as psoriasis and rosacea have
Correspondence: Allard R. J. V. Vossen, M.D., Department of Dermatology, Erasmus University Medical Center, Burgemeester s’ Jacobplein 51, 3015 CA Rotterdam, The Netherlands. Email:
[email protected] Prior presentation: The content of this manuscript has been used in an oral presentation in the 5th Conference of the European Hidradenitis Suppurativa Foundation (EHSF), 10–12 February 2016 in Berlin. Received 14 June 2016; accepted 29 July 2016.
© 2016 Japanese Dermatological Association
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A.R.J.V. Vossen et al.
Figure 1. Schematic display of an apple- and pear-shaped body. (a) Associated with visceral fat accumulation and a higher cardiovascular risk profile. (b) Associated with peripheral subcutaneous fat accumulation and a lower cardiovascular risk profile. been associated with cardiovascular morbidity.16,17 Several studies suggest that there is an association between HS and the metabolic syndrome.18 To date, studies on the WHR in patients with HS are scarce.7 The WHR together with the BMI will provide information about body type and proportion. The objective of our study was to simultaneously calculate BMI and WHR in individuals with HS compared with a general dermatological population in order to determine the body types.
Caucasians (i.e. Europeans). In the HS group, only patients with a physician-verified diagnosis of HS were included. The control group consisted of frequency age- and sex-matched non-HS dermatological patients in a 1:2 ratio. In both groups, pregnant women and individuals with an abdominal wall hernia were excluded. Individuals in the control group underwent the same examination as HS patients.
Outcome
METHODS Study design This was a hospital-based cross-sectional joint study comparing HS patients with a general dermatological population. Consecutive patients with HS were asked to participate. The general dermatological population consisted of randomly selected patients who did not suffer from HS. The performed measurements were height and weight resulting in a BMI, and a waist and hip circumference resulting in a WHR.
Study population In both groups, adult (≥18 years of age) individuals from the Departments of Dermatology of the Deventer Hospital and the Erasmus University Medical Center in the Netherlands were investigated. Study participants mainly consisted of
2
All participants were measured in a standardized manner by trained staff. Morphometric parameters included height, weight, waist circumference and hip circumference. According to the World Health Organization’s STEPwise Approach to Surveillance (STEPS), the waist circumference was measured with a stretch-resistant tape in the middle/center between the inferior margin of the most caudal palpable rib and the superior border of the iliac crest. Guidance and recommendations for the effective use of specific cut-off points for BMI and WHR were applied.19 We used the globally accepted classification system for BMI. The WHR has sex-adjusted cut-off points (Table 1). A waist circumference of 94 cm or more for European males and a waist circumference of 80 cm or more for European females is associated with substantially increased risk of metabolic complications.20 In accordance with the cutoff points for BMI and WHR in Table 1, we defined central
© 2016 Japanese Dermatological Association
Body type in hidradenitis suppurativa
obesity as a BMI of 30 or more in combination with a WHR of 0.90 or more for men and a WHR of 0.85 or more for women. Peripheral obesity was specified as a BMI of 30 or more in combination with a WHR of less than 0.90 for men and a WHR of less than 0.85 for women. Disease severity was assessed using the Hurley classification of the worst location affected.21 Hurley stage I is limited to single or multiple abscesses without sinus tracts or scarring.22 Stage II consists of widely separated single or multiple recurrent abscesses with sinus tract formation and scarring. Hurley III is present when an entire anatomical area is diffusely involved with multiple interconnected tracts. A positive family history was assumed if patients reported first- or seconddegree relatives with HS symptoms.
Statistical analysis The clinical parameters were collected during routine care and derived from medical charts. In the background characteristics, variables were either continuous or categorical, while the measurements were continuous. Patient characteristics were presented using descriptive statistics with continuous data as the mean standard deviation (SD) or the median with interquartile range (IQR) and categorical data as number (%). We used the median with IQR according to the Mann–Whitney U-test for sexadjusted analysis in men. The independent t-test was performed for comparison of patient characteristics in women and the unadjusted analysis. The v2-test was used for categorical data. A twosided P-value of 0.05 was considered statistically significant. We corrected for multiple testing by a false discovery rate according to the Benjamini–Hochberg procedure with a corresponding P-value of 0.0125. The data analysis was implemented by the 21st version of IBM-SPSS statistics (IBM, Armonk, NY, USA).
Ethical statement This study was approved by the ethics committee of the Erasmus Medical Center (project no. MEC-2016-084) in the Netherlands. According to the Medical Research involving Human
Table 1. Cut-off points circumference and WHR
for
body
mass
index,
BMI (kg/m2) Underweight Normal Overweight Obesity Extreme obesity
Men Women
40
waist
Obesity class
RESULTS One hundred and six HS patients and 212 controls of a general dermatological population were included. Background characteristics showed that HS subjects were more frequently smokers compared with controls (Table 2). The disease onset in HS patients varied between the age of 7 and 65 years with a median of 22.0 years. The most frequently occurring disease severity in HS patients was Hurley stage II (53.8%). A positive family history for HS was reported by 24.5%, while a negative and unknown family history was reported by 46.2% and 19.3%, respectively, of HS individuals. The control group included patients with a heterogeneous subset of dermatological diseases. Eczema, benign nevi, warts and (pre)malignancies were the three most common diagnoses (53.3% of total) in the nonHS dermatological population. Patients with HS had a significantly higher BMI compared with controls, at 27.8 5.4 and 25.6 4.8, respectively (P < 0.001) (Table 2). In the HS population, men tended to be more obese (BMI, 28.6 6.2) than women (BMI, 27.6 5.1). The WHR did not significantly differ between HS patients and the control group, at 0.87 0.11 and 0.89 0.09, respectively (P > 0.05) (Table 2). Sex-adjusted analysis in the HS population versus the control population showed a similar near to normal WHR in women (0.84 0.10 vs 0.85 0.09, P > 0.05). There was no difference in the WHR of men (0.96 [0.88–1.06] vs 0.96 [0.92–1.0], P > 0.05). Additionally, independent of the WHR, women with HS had larger hip circumference compared with controls (P = 0.001). The hip circumference in women of the HS and control population was 106.3 13.0 and 100.0 12.9 cm, respectively. A subset analysis of obese individuals revealed that HS patients had more peripheral rather than central weight distribution compared with the control group. Peripherally distributed bodyweight was present in 43% of 37 obese HS individuals versus 19% of 31 obese patients in the general dermatological population (P = 0.036) (Table 3). In general, 47.6% of the women compared with 12.5% of the men displayed a pattern of peripheral distribution of bodyweight.
DISCUSSION I II III
Waist circumference† (cm)
WHR
≥94 (≥102) ≥80 (≥88)
≥0.90 ≥0.85
Adapted from “Waist circumference and waist–hip ratio” Report of a World Health Organization expert consultation 2008. †Waist circumference associated with increased risks of metabolic complications for Europeans. Numbers between round brackets indicate a substantially increased risk. BMI, body mass index; WHR, waist-to-hip ratio.
© 2016 Japanese Dermatological Association
Subjects Act (Dutch abbreviation: WMO) this study was classified as non-WMO liable research.
This study confirms that patients with HS have a higher BMI compared with the general dermatological population. The elevated BMI found in patients with HS, together with a similar WHR in both groups, suggests a tendency of peripheral weight distribution due to subcutaneous fat accumulation, thereby influencing body morphology. Indications for the presence of an adverse metabolic profile in HS can be speculated based on elevated BMI. Overweight and obesity in HS individuals demonstrated in this study are in accordance with the published work.9,10,23 In our study, the WHR did not differ between HS individuals and controls, which implies that in HS there is no association with the metabolic
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Table 2. Background and morphometric characteristics HS population n = 106 Female sex (%) Age (years), mean SD Smoking status (%) Present smoker Past smoker Never smoked Pack-years smoking, mean SD HS severity distribution (%) Hurley I Hurley II Hurley III Diagnosis not HS Eczema Benign nevus or verruca Skin (pre-)malignancy Psoriasis Allergy (not eczema) Acne/folliculitis Other skin disease Height (cm) Men Women Weight (kg) Men Women BMI (kg/m2) Men Women Waist (cm) Men Women Hip (cm) Men Women WHR Men Women
Controls n = 212
79 (75.2%) 41.15 11.3
P
142 (67%) 42.8 10.8
81 (82.7%) 12 (12.2%) 5 (5.1%) 19.6 12.8
0.13 0.20
