Abstract
Background
Dupuytren's contracture (DC) and
Methods
We estimated DC prevalence in two cohorts of white Alabama hemochromatosis probands (294 C282Y homozygotes, 67 C282Y/H63D compound heterozygotes) in a retrospective study. We performed logistic regressions on DC using the following independent variables: age, body mass index, heavy ethanol consumption, serum ferritin, elevated serum AST/ALT, non-alcoholic fatty liver disease, viral hepatitis, cirrhosis, and diabetes.
Results
One man and two women with C282Y homozygosity had DC (prevalence 1.02%; 95% CI 0.35%–2.96%). A man with C282Y/H63D had DC (prevalence 1.49%; 95% CI 0.26%–7.98%). DC occurred as an autosomal dominant trait in his kinship. In regression analyses, no single variable predicted DC. We observed no new DC cases after the diagnosis of hemochromatosis (mean follow-up 12.9 ± 7.5 years (1 SD), and 9.0 ±5.1 years, respectively).
Conclusions
Our prevalence estimates of DC in white Alabama hemochromatosis probands are similar to those found in the white US population cohorts. DC risk was unrelated to the variables we studied.
Introduction
Dupuytren's contracture (DC) is a distinctive but heterogeneous fibroproliferative disorder of the palmar fascia characterized by nodular growth and proliferation; cord development and contracture; 12 increased hexosamine and collagen contents; and an elevated ratio of Type 3 to Type 1 collagen. 3 DC is common in some northwestern European populations, especially those of Viking or Celtic descent,4–7 suggesting that there may be a genetic predisposition to develop DC. Lifestyle and occupational factors and comorbid conditions may also increase one's risk of developing DC.6,8–10
Persons with
Methods
Selection of Hemochromatosis Probands
The performance of this work was approved by the Institutional Review Board of Brookwood Medical Center. We conducted computerized and manual searches of medical records and hemochromatosis databases to identify all patients evaluated for hemochromatosis because they had elevated values of transferrin saturation or serum ferritin (SF). Each patient selected for this study was Caucasian and was the first in his/her family to be diagnosed with hemochromatosis (proband). We included persons who: (a) were diagnosed with hemochromatosis in non-screening venues; (b) had
Diagnosis of Dupuytren'S Contracture
The diagnosis of DC was established in three patients during physical examination. These patients fulfilled the following clinical criteria for the diagnosis of DC: nodularity and cord-like thickening of the palmar fascia and the presence of fixed flexion contractures of the metacarpophalangeal joint or proximal interphalangeal joint of 20 degrees or more in one or more digits. In a fourth patient, we reviewed the history, operative report of surgery for DC, and pathologists’ interpretation of tissue removed at surgery and deemed this case to be consistent with DC as defined in the three other patients. In all cases, phenotype mimics of DC were excluded as appropriate. These mimics include scar formation from trauma or burns, various benign cysts and nodules, sequelae of reflex sympathetic dystrophy, recurrent digital fibroma of childhood, and palmar epithelioid sarcoma.
Laboratory Methods
SF levels were measured using automated clinical methods.
Sections of liver biopsy specimens were stained using hematoxylin and eosin, Masson's trichrome, and Perls’ Prussian blue techniques. Intrahepatocytic iron was graded according to the method of Scheuer et al. 30 Routine methods were used to detect HBsAg, HBsAb, HBsAb, and the hepatitis C antibody.
Diagnosis of Liver Conditions
We defined five liver conditions as: elevated serum level(s) of hepatic aminotransferase levels; non-alcoholic fatty liver disease (NAFLD); heavy ethanol consumption; chronic hepatitis B or C; and cirrhosis. 31 Patients were classified as having elevated aminotransferase levels if either their serum aspartate or alanine aminotransferase (AST, ALT, respectively) level was higher than the respective upper reference limit (>2 SD above the mean). NAFLD was defined as steatosis or steatohepatitis detected on liver biopsy specimens or by a typical increase in hepatic echogenicity detected by ultrasonography in the absence of self-reports of heavy ethanol consumption. Heavy ethanol consumption was defined as the self-reported consumption of ≥60 g/d for five or more years. Chronic hepatitis B or C was defined as positivity for HBsAg or hepatitis C antibody, respectively, in association with clinical or liver biopsy abnormalities consistent with chronic viral hepatitis.
Liver biopsy was typically performed in probands who had SF > 1000 μg/L at diagnosis, or in whom there was evidence of unexplained liver disease regardless of SF level. 24 Cirrhosis was defined by pathologists’ interpretations of liver biopsy specimens.
Treatment of Iron Overload Manifestations
Iron depletion therapy, defined as the periodic removal of blood to eliminate storage iron, was performed as described in detail elsewhere.13,24 An attempt to achieve iron depletion by phlebotomy was made in each proband with elevated SF levels. Hepatic, cardiac, endocrinologic, and rheumatologic manifestations of iron overload were evaluated and treated as described previously.13,24
Statistics
One analytic data set consisted of observations on 294 Alabama hemochromatosis probands with
All living patients were so confirmed on May 1, 2012. The dates of death of other patients were confirmed by review of office and hospital records and by the Social Security Death Index (http://ssdi.rootsweb.ancestry.com/). Duration of follow-up after diagnosis was computed using the date of diagnosis and either May 1, 2012 (living patients) or date of death, as appropriate.
SF levels were converted to natural logarithms (ln) to normalize them for univariable comparisons. Mean SF results are displayed as anti-ln of mean ln SF (95% confidence interval (CI)). Descriptive statistics are displayed as enumerations, percentages, or mean ± 1 standard deviation (SD). Comparisons of continuous data were made using Student's two-sided
Results
Characteristics of Alabama Hemochromatosis Probands with DC
Three of the 294 patients with
Characteristics of four hemochromatosis probands with Dupuytren's contracture a .
Notes:
Characteristics are those at diagnosis of hemochromatosis;
underwent surgery to correct DC before diagnosis of hemochromatosis. No proband reported ethanol consumption ≥ 60 g/d for five or more years or had non-alcoholic fatty liver disease or viral hepatitis.
One of the 67 patients with

Pedigree of Proband 4, a man with
Characteristics of Alabama Hemochromatosis Probands without DC
Observations of the 291 patients with
Characteristics of 291 white hemochromatosis probands with
Characteristics are those at diagnosis of hemochromatosis;
comparisons were made using student's
self-report of ethanol consumption of ≥60 g/d for five or more years.
Characteristics of 66 white hemochromatosis probands with
Characteristics are those at diagnosis of hemochromatosis;
comparisons were made using student's
self-report of ethanol consumption of ≥60 g/d for five or more years.
Comparisons of Alabama Hemochromatosis Probands with and without DC
Among
Logistic Regressions on Occurrence of DC
We performed logistic regressions on the presence of DC (dependent variable) in 294 probands with
Discussion
The present observations demonstrate that the prevalence of DC in white Alabama hemochromatosis probands with either
The prevalence of DC is much higher in some northwestern European populations, especially those of Viking or Celtic descent, than in Americans. In Iceland, for example, 19.2% of 1297 males and 4.4% of 868 female participants in a random population sample between the ages of 46 and 74 years old presented with clinical signs of Dupuytren's disease. 6 In Norway, the prevalence of DC approaches 30% in persons aged 60 years or older. 36 In Northeast Scotland, 39% of men and 21% of women aged more than 60 years had DC. 5 DC was present in 13.75% of 400 elderly exservicemen from England or Ireland living at the Royal Hospital Chelsea. 37 These modern estimates agree with historic accounts of DC in Europe.38–40
The prevalence of
DC is often inherited as an autosomal dominant trait with variable penetrance that has been observed most frequently among people of Nordic descent. 36 This is consistent with the occurrence of DC in Proband 4 and his family members who reported having Irish ancestry. The pattern of inheritance of DC occurs rarely as an autosomal recessive or matrilinear trait.42,43 We obtained no family history of DC in three other hemochromatosis probands with DC, although this does not exclude a contribution of heritable factors to DC phenotypes.
Many candidate chromosomes, genes, and single-nucleotide polymorphisms that might explain DC have been identified in family, linkage analysis, genome-wide associations, and other studies.
42
There is a significant positive association of DC with HLA-DRB1-*15 (chromosome 6p21.3).
44
In patients of northwest European ancestry with multiple sclerosis in Victoria and Tasmania, the results of linkage disequilibrium and log linear modeling analyses suggest that the frequency of
The increased frequency of HLA-DRB1-*15 in patients with DC suggests a possible role of the ancestral haplotype HLA-A1-B8-DR3.
47
The frequency of the HLA-A*01, B*08 haplotype was similar in 118 Alabama hemochromatosis probands and 1,321 white control subjects (0.0720 and 0.0669, respectively).
27
None of the three
The prevalence of DC among Native Americans in the US is lower than that in Caucasians. 34 Approximately one-quarter of Alabama hemochromatosis probands and controls reported being of Native American ancestry. 41 Native American ancestry could account in part for the relatively low prevalence of DC that we observed in the present hemochromatosis probands, and it may also account for the lower prevalence estimates of DC in other population samples of Americans32–34 when compared to northwestern Europeans.5,6,36,37
The present results suggest that there is no significant association of risk of DC in hemochromatosis probands and their severity of iron overload. In the four probands who had DC, SF levels at diagnosis varied widely. The mean SF level at diagnosis in the present
Lifestyle, occupational factors, and comorbid disorders in western Europeans have been reported to be associated with an increased risk of DC. These factors and disorders include: (1) cigarette smoking; 8 (2) low body mass index; 6 (3) heavy ethanol consumption; 9 (4) elevated blood glucose levels; 6 and (5) occupational hand trauma.6,9,10 In contrast, another large study did not confirm a significant relationship between DC and cigarette smoking, heavy ethanol consumption, or diabetes. 7 We observed no association of body mass index, heavy ethanol consumption, or diabetes with DC in the present cohort.
Our prevalence estimates may be conservative because some probands may have had other fibroproliferative conditions associated with DC that we did not assess, including Peyronie disease, knuckle pads, congenital generalized fibromatosis, juvenile fibromatosis, or frozen shoulder. 49 Our relatively low prevalence estimates of DC may have decreased our ability to detect significant predictors of DC, if they exist, using logistic regressions. Because the prevalence of DC increases with age, it is possible that other hemochromatosis probands in our cohorts will eventually develop DC. On the other hand, none of the present probands developed DC after diagnosis of hemochromatosis. The relatively long follow-up intervals for both of the present hemochromatosis cohorts suggest that the number of any future cases of DC may be small.
Conclusions
The prevalence of DC in Caucasian hemochromatosis probands who reside in central Alabama is similar to that in reported in other US Caucasian population cohorts, and the severity of iron overload and other characteristics of hemochromatosis typically assessed at diagnosis are not significant predictors of the occurrence of DC. The relatively high proportion of Native American ancestry among white Alabama hemochromatosis probands and in white control subjects could account in part for the lower prevalence estimates of DC in US whites than in whites who reside in northwestern Europe.
Funding Sources
This work was supported in part by Southern Iron Disorders Center.
Competing Interests
Author(s) disclose no potential conflicts of interest.
Author Contributions
JaCB conceived this work and examined all probands. JaCB and JClB tabulated data and performed statistical analyses. JaCB wrote the first draft of the manuscript. JaCB and JClB revised and approved the manuscript in its final form.
Disclosures and Ethics
As a requirement of publication, the author(s) have provided to the publisher signed confirmation of compliance with legal and ethical obligations including but not limited to the following: authorship and contributorship, conflicts of interest, privacy and confidentiality and (where applicable) protection of human and animal research subjects. The authors have read and confirmed their agreement with the ICMJE authorship and conflict of interest criteria. The authors have also confirmed that this article is unique and not under consideration or published in any other publication, and that they have permission from rights holders to reproduce any copyrighted material. The authors have no disclosures to make. The external blind peer reviewers report no conflicts of interest.
