Summary
Background
The relationship between tobacco use and hidradenitis suppurativa (HS) is controversial.
Objectives
To determine the incidence of HS among tobacco smokers.
Methods
Retrospective ...cohort analysis identifying incident HS cases among adult tobacco smokers and nonsmokers sampled from a demographically heterogeneous population‐based sample of over 50 million unique patients across all census regions in the U.S.A.
Results
We identified 3 924 310 tobacco smokers, which included 7860 patients newly diagnosed with HS. Tobacco smokers diagnosed with HS were most commonly aged 18–39 years (3795 of 7860; 48·3%), women (5640 of 7860; 71·8%), white (5200 of 7860; 66·2%) and those with body mass index (BMI) ≥ 30 (5690 of 7860; 72·4%). Overall incidence of HS was 0·20% (7860 of 3 924 310) among tobacco smokers and 0·11% (8430 of 8 027 790) among nonsmokers (P < 0·001). Incidence was greatest among tobacco smokers who were aged 30–39 years (0·35%), women (0·28%), African Americans (0·46%) and those with BMI ≥ 30 (0·33%). The overall adjusted odds of developing HS was 1·90 (95% confidence interval 1·84–1·96) among tobacco smokers, compared with nonsmokers (P < 0·001). HS incidence among tobacco smokers remained increased within each demographic subgroup.
Conclusions
Incidence of HS appears to be doubled among tobacco smokers. These findings may support evidence‐based counselling efforts for the cessation of smoking in populations at risk for HS.
What's already known about this topic?
Despite a common belief that tobacco smoking is associated with hidradenitis suppurativa (HS) and represents a risk factor for developing the disease, the evidence linking the two conditions is controversial in the medical literature.
Cohorts demonstrating the association are smaller and nondiversified. Moreover, there are several published cohorts within which tobacco smoking has no association with HS.
What does this study add?
Among a demographically heterogeneous population‐based sample of almost 4 million tobacco smokers, the overall incidence of HS among tobacco smokers is 0·20%.
The overall odds of incident HS among tobacco smokers is also nearly twice that of nonsmokers.
HS incidence among tobacco smokers remained increased across demographic subgroups.
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Summary
Background
A temporal relationship between hidradenitis suppurativa (HS) and obesity has not been established.
Objectives
To compare baseline body mass index (BMI) and change in BMI for ...patients with HS and controls before and after diagnosis.
Methods
We performed a retrospective case–control analysis of 1284 patients with HS and controls matched for age, sex, race and calendar year between 1 January 1999 and 9 September 2019. BMI 7 years prior to first HS diagnosis, and rate of BMI change, were compared for patients with HS and controls using linear mixed effects models.
Results
Baseline BMI was higher among patients with HS than controls mean difference 3·03 kg m−2, 95% confidence interval (CI) 2·44–3·62; P < 0·001). This difference was larger for women mean difference 3·37 kg m−2 (95% CI 2·73–4·01) than men mean difference 1·27 kg m−2 (95% CI − 0·20–2·73; interaction P = 0·01), and for patients with HS diagnosed before age 40 years mean difference 4·10 kg m−2 (95% CI 3·15–5·06) than those diagnosed after age 40 years mean difference 2·38 kg m−2 (95% CI 1·63–3·12; interaction P < 0·001). Prior to diagnosis, average annual increase in BMI among patients with HS was slightly higher than controls. There was no statistically significant change in annual BMI among patients with HS following diagnosis.
Conclusions
Baseline BMI and, to a lesser extent, rate of BMI change appear to be risk factors for developing HS. The influence of BMI may play a larger role among female patients and younger patients.
What is already known about this topic?
The association between hidradenitis suppurativa (HS) and obesity is well established.
However, whether obesity influences the development of HS or is a consequence of having HS is unknown.
What does this study add?
We have observed that obesity and, to a lesser extent, rate of change in body mass index appear to be risk factors for developing HS.
Linked Comment: L.A.V. Orenstein. Br J Dermatol 2021; 185:6–7.
Summary
Background
Hidradenitis suppurativa (HS) has been linked to Down syndrome (DS).
Objectives
To determine whether patients with DS have a higher prevalence of HS, and whether the diagnosis of ...HS occurs at an earlier age for these patients.
Methods
A cross‐sectional analysis was performed for a population sample of 11 936 patients with DS and 16 813 290 patients without DS. The primary outcome was the diagnosis of HS. Systemized Nomenclature of Medicine–Clinical Terms were used to identify patients with DS and HS. We used logistic regression models and significant interaction terms to evaluate the relationship between DS and HS. We also compared the proportion of incident HS cases within 5‐year age groups to determine whether patients with DS had received an earlier diagnosis of HS.
Results
Prevalence of HS among patients with DS was 2·1%, compared with 0·3% for patients without DS (P < 0·001). HS prevalence was greatest among patients with DS who were aged 18–29 years. After controlling for age, sex and obesity, there was no difference in the prevalence of HS between female and male patients with DS or between white and nonwhite patients with DS. Compared with patients without DS, patients with DS had increased odds of HS in unadjusted odds ratio (OR) 7·84, 95% confidence interval (CI) 6·93–8·88 and adjusted (OR 5·24, 95% CI 4·62–5·94) analyses. HS was diagnosed by the age of 29 years in 81·8% of patients with DS, compared with 34·0% of patients without DS (P < 0·001).
Conclusions
HS is strongly associated with DS across demographic subgroups and may present earlier in life for these patients.
What's already known about this topic?
Evidence suggests a potential genetic link that predisposes patients with Down syndrome (DS) to the development of hidradenitis suppurativa (HS).
There is limited observational data to support this association.
What does this study add?
In this population‐based cross‐sectional analysis, a prevalence of 2·1% for HS was observed in patients with DS.
Patients with DS were over five times more likely to develop HS compared with patients without DS.
HS is diagnosed earlier in life for patients with DS.
Linked Comment: Micheletti. Br J Dermatol 2018; 178:587–588.
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Summary
Hidradenitis suppurativa (HS) is a chronic, recurrent, and painful disease in which there is inflammation in areas of the apocrine sweat glands. These glands are found mainly in the armpits ...and groins. Within HS there may be a blockage of the hair follicles. This causes a mixture of boil‐like lumps, areas leaking pus, and scarring. Despite a common belief that tobacco smoking increases the risk of developing the disease, the evidence linking the two is controversial. This study is important because it includes a very large sample of people to compare rates of HS in smokers and non‐smokers. Using healthcare data, the researchers identified 3 924 310 tobacco smokers and 8 027 790 non‐smokers in the USA and found that the overall incidence of HS was 0.20% among smokers and 0.11% among non‐smokers. Incidence of HS was greatest among smokers who were aged 30–39 years (0.35%), women (0.28%), African Americans (0.46%), and those with BMI ≥ 30. In conclusion, incidence of HS appears to be doubled among tobacco smokers. These findings may support evidence‐based counselling to help people at risk of HS to quit smoking.
Linked Article: Garg et al. Br J Dermatol 2018; 178:709–714
Summary
Hidradenitis suppurativa (HS) is a debilitating, chronic, painful inflammatory disease. Scientists have previously suggested that there is a potential genetic link predisposing Down syndrome ...patients to the development of HS through the increased formation of the amyloid precursor protein. However, this laboratory based finding had not previously been verified in the population. In this study, we evaluated the commonness of hidradenitis suppurativa within a large group of patients who had Down syndrome, and we used another groups of patients that did not have Down syndrome to compare findings. We observed that the diagnosis of hidradenitis suppurativa was present among 2.1% of patients with Down syndrome over the past five years. Compared to those without Down syndrome, patients with the condition had five times the likelihood of having hidradenitis suppurativa during the period of the study. Hidradenitis suppurativa was most common among Down syndrome patients who were aged 18–29 years. Hidradenitis suppurativa affected males and females, and whites and non‐whites, with Down syndrome equally. The diagnosis of hidradenitis suppurativa is made at a younger age among patients with Down syndrome, compared to patients without the condition. This suggests that hidradenitis may occur earlier in life among patients with Down syndrome, or it may occur more severely and thereby prompt earlier visits to the doctor for this condition. It is also possible that hidradenitis suppurativa is diagnosed earlier among patients with Down syndrome because doctors may be examining patients with Down syndrome more frequently in general.
Linked Article: Garg et al. Br J Dermatol 2018; 178:697–703
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