Prognostic and functional importance of both overt and subclinical left ventricular systolic dysfunction in systemic sclerosis.

OBJECTIVES: To quantify the frequency and clinical implications of systemic sclerosis (SSc)-associated left ventricular function (LV) impairment. METHODS: Australian Scleroderma Cohort Study participants meeting ACR/EULAR criteria for SSc with ≥1 echocardiographic LVEF measurement were included. Overt LV dysfunction was indicated by reduced LV ejection fraction (LVEF) and subclinical LV dysfunction was measured using impaired LV global longitudinal strain (LV-GLS>-16 %). Those with secondary causes of LV dysfunction (myocardial ischaemia, valvulopathy and pulmonary arterial hypertension) were excluded. Chi-squared tests, two-sample t-tests or Wilcoxon rank-sum tests were used for between-group comparison as appropriate. Generalised estimating equations(GEE) were used to model longitudinal data. Kaplan-Meier and Cox proportional hazard models were used for survival analyses. RESULTS: Of 1141 participants with no co-morbid cardiac disease, 2.4 % ever recorded a LVEF<50 %, while only 0.6 % ever recorded a LVEF≤40 %. LV-GLS data were available for 90 % of participants at one centre (n = 218). Impaired LV-GLS was detected in 21 % despite LVEF≥50 %. Those with a LVEF<50 % were more frequently male (p = 0.01) with dcSSc (p < 0.01), higher inflammatory markers (p < 0.02) and skeletal muscle disease (p < 0.05). In multivariable analyses, recording a LVEF<50 % was associated with increased mortality (HR2.3, 95 %CI1.0-4.8, p = 0.04). Impaired LV-GLS was also associated with poorer survival in univariable analyses (HR3.4, 95 %CI1.0-11.8, p = 0.05). Those with a LVEF<50 % more frequently recorded WHO Class III/IV dyspnoea (OR3.5, 95 %CI1.6-7.7, p < 0.01), with shorter six-minute walk distance (p = 0.01), higher Health Assessment Questionnaire-Disability Index scores (p < 0.01) and lower Short Form-36 Physical Component Summary scores (p = 0.02). Increased dyspnoea (WHO Class III/IV dyspnoea; OR3.6, 95 %CI1.4-9.2, p < 0.01) was also seen in those with impaired LV-GLS. CONCLUSIONS: Both overt and subclinical SSc-associated LV dysfunction are associated with worse survival and impaired physical function. The frequency of abnormal LV-GLS in those with consistently normal LVEF suggests an under-appreciated burden of subtle LV systolic dysfunction in SSc that has a significant impact on patient symptomatology.

Proximal weakness and creatine kinase elevation in systemic sclerosis: Clinical correlates, prognosis and functional implications.

OBJECTIVES: To determine the frequency, clinical correlates and implications of clinical evidence of muscle disease in systemic sclerosis (SSc). METHODS: Australian Scleroderma Cohort Study participants with ≥1 creatine kinase (CK) and proximal power assessment were subdivided according to presence of proximal weakness (PW: proximal muscle power<5/5) and CK elevation(≥140IU/L). Participants were assigned to one of four groups: concurrent PW&CK elevation, PW alone, CK elevation alone or neither. Between-group comparisons were made with chi-squared, ANOVA or Kruskal-Wallis tests. Survival analysis was performed using time-varying-covariate Cox regression modelling. Longitudinal data were modelled using multinomial logistic and linear regression. RESULTS: Of 1786 participants, 4 % had concurrent PW&CK elevation, 15 % PW alone, 24 % CK elevation and 57 % neither. Participants with PW&CK elevation displayed a severe, inflammatory SSc phenotype, with more frequent dcSSc(p < 0.01), tendon friction rubs(p < 0.01), synovitis(p < 0.01) and digital ulceration(p = 0.03). Multimorbidity(p < 0.01) and cardiopulmonary disease, including ischaemic heart disease(p < 0.01) and pulmonary arterial hypertension(p < 0.01), were most common in those with PW, with and without CK elevation. Men with anti-Scl70 positivity most frequently had CK elevation alone, without other significant clinical differences. Multivariable modelling demonstrated 3.6-fold increased mortality in those with PW&CK elevation (95 %CI 1.9-6.6, p < 0.01) and 2.1-fold increased mortality in PW alone (95 %CI 1.4-3.0, p < 0.01) compared to those without PW or CK elevation. CK elevation alone conferred better survival (HR 0.7, 95 %CI 0.4-1.1, p = 0.09) compared to those with no PW or CK elevation. PW regardless of CK elevation was associated with impaired physical function, with reduced six-minute-walk-distance (p < 0.01), higher HAQ-DI scores (p < 0.01) and increased patient-reported dyspnoea (p = 0.04). CONCLUSION: Clinical features of myopathy are highly prevalent in SSc, affecting almost half of our study cohort. Detection of PW and elevated CK alone, even without imaging or histopathological identification of SSc-myopathy, identified important clinical associations and are associated with poorer function and overall prognosis.

Inflammatory Arthritis in Systemic Sclerosis: Its Epidemiology, Associations, and Morbidity.

OBJECTIVE: To describe the epidemiology, associations, and impact of inflammatory arthritis (IA) in systemic sclerosis (SSc). METHODS: Patients with SSc prospectively enrolled in the Australian Scleroderma Cohort Study were included. IA was defined clinically as the presence of synovitis on examination. Logistic regression was used to determine the associations of IA with SSc manifestations and serological parameters. Patient-reported outcome measures were used to capture physical function and health-related quality of life (HRQoL). RESULTS: IA was a common SSc manifestation affecting one-third (33.3%) of patients over a median follow-up of 4.3 (1.7-8.4) years. Associations of IA included diffuse SSc (odds ratio [OR] 1.33, 95% confidence interval [95% CI] 1.01-1.74, P = 0.042), concurrent musculoskeletal manifestations (joint contractures and tendon friction rubs, OR 1.70, 95% CI 1.34-2.15, P < 0.001); myositis (OR 2.11, 95% CI 1.39-3.20, P < 0.001), and sicca symptoms (OR 1.57, 95% CI 1.14-2.16, P = 0.006), whereas IA was negatively associated with pulmonary arterial hypertension (OR 0.52, 95% CI 0.35-0.78, P = 0.002). Neither the presence of rheumatoid factor nor U1 small nuclear RNP were associated with IA (OR 1.13, 95% CI 0.88-1.44, P = 0.331, OR 1.46, 95% CI 0.89-2.39, P = 0.129 respectively). Positive anticyclic citrullinated protein antibodies, although at low frequency, were more common in those with IA compared with those without IA (7.5% vs 1.5%, P < 0.001). IA was associated with significantly lower HRQoL score (P < 0.001) and more physical disability than in those without IA (P < 0.001). CONCLUSION: IA is a common disease manifestation that is more frquently seen in diffuse disease. IA is associated with poor HRQoL and physical disability. Further research is needed into the effective management of IA in SSc.

Impact of the COVID-19 Pandemic on Health Care Access and Diagnosis of Pulmonary Arterial Hypertension Among Patients With Systemic Sclerosis.

OBJECTIVE: Regular clinical assessment for complications of systemic sclerosis (SSc) such as pulmonary arterial hypertension (PAH) is essential for early institution of therapy and improved outcomes. The objective of this study was to determine the impact of COVID-19 pandemic-related restrictions on health care access of patients with SSc, including screening for PAH. METHODS: South Australian and Victorian patients enrolled in the Australian Scleroderma Cohort Study were surveyed about their perceptions of the impact of the pandemic on mental well-being, access to medications, investigations, and management of SSc. Frequency of annual rheumatology assessments, pulmonary function tests (PFT), and transthoracic echocardiography (TTE) to screen for PAH were compared with rates from before the pandemic. RESULTS: A total of 312 of 810 patients with SSc responded (38.5% response); 273 were female (87.5%), the median age was 64.7 years, 77.2% had limited disease, the median illness duration was 15.6 years, 15.7% were immunosuppressed, 32.1% had interstitial lung disease, and 6.4% had PAH. A total of 65.7% of consultations were by telehealth, of which 81.2% were by telephone. Compared with respondents in South Australia (n = 109), Victorian respondents (n = 203) experiencing prolonged lockdown, reported reduced access to their rheumatologist (49.3% vs 27.9%; P = 0.004), greater use of consultation by video (17.3% vs 2.1%; P = 0.008), greater health care disruption (49.0% vs 23.2%; P < 0.001), and worse mental health (P = 0.002). Respondents reported reduced access to PFT and TTE (31.7% and 22.5%, respectively). Annual visits, PFT, TTE, and new diagnoses of PAH were reduced in 2020 to 2022 compared with 2011 to 2019. CONCLUSION: The COVID-19 pandemic-related disruption to health care for patients with SSc was associated with worse mental health and reduced screening and diagnosis of PAH, which may impact long-term outcomes.

Clinical Features of Systemic Sclerosis-Mixed Connective Tissue Disease and Systemic Sclerosis Overlap Syndromes.

OBJECTIVE: To describe the clinical characteristics and outcomes of systemic sclerosis-mixed connective tissue disease (SSc-MCTD) and SSc overlap syndrome. METHODS: We included patients from the Australian Scleroderma Cohort Study who met American College of Rheumatology/European Alliance of Associations for Rheumatology criteria for SSc. Three mutually exclusive groups were created: SSc-MCTD, SSc overlap, and SSc only. Univariate comparison of clinical features was performed by analysis of variance or chi-square test. Survival analysis was performed using Kaplan-Meier (KM) curves and Cox proportional hazards regression models. RESULTS: Of 1,728 patients, 97 (5.6%) had SSc-MCTD, and 126 (7.3%) had SSc overlap. Those with MCTD-SSc were more commonly Asian (18.3% versus 10.1% in SSc overlap, and 3.6% in SSc only; P < 0.0001) and younger at disease onset (38.4 years versus 46.5 or 46.8 years, P < 0.0001). Those with SSc-MCTD or SSc overlap were more likely to have limited cutaneous SSc. All 3 groups had similar frequency of interstitial lung disease (ILD), although pulmonary arterial hypertension (PAH) was less common in SSc overlap. Synovitis and myositis were more common in SSc overlap and SSc-MCTD than in SSc only. KM curves showed better survival in SSc-MCTD than SSc overlap or SSc only (P = 0.011), but this was not significant after adjustment for sex and age at disease onset. SSc-specific antibodies were survival prognostic markers, with antinuclear antibody centromere or anti-RNP conferring better survival than anti-Scl-70 or anti-RNA polymerase III (P = 0.005). Patients with SSc-MCTD and SSc overlap had lower mortality following diagnosis of ILD and PAH than patients with SSc only. CONCLUSION: This study provides insights into the clinical characteristics of patients with SSc-MCTD, SSc overlap, and SSc only and shows that anti-RNP antibodies are associated with better survival than anti-Scl-70 and anti-RNA polymerase III antibodies.

Occupational silica exposure in an Australian systemic sclerosis cohort.

OBJECTIVE: To determine the frequency of self-reported occupational exposure to silica in SSc patients enrolled in the Australian Scleroderma Cohort Study, and to compare the disease characteristics of the silica-exposed patients with those of the non-exposed patients. METHOD: Data collected over a 12-year period from 1670 SSc patients were analysed. We compared the demographic and clinical characteristics of those who reported occupational silica exposure with those who did not. A subgroup analysis of male patients was performed, as well as a multivariable analysis of correlates of silica exposure. RESULTS: Overall, 126 (7.5%) of the cohort reported occupational silica exposure. These individuals were more likely to be male (73 of 231, i.e. 31.6% males exposed) and to have worked in mining and construction industries. Those who reported silica exposure were younger at the onset of SSc skin involvement [odds ratio (OR) 0.9, P = 0.02], of male gender (OR 14.9, P < 0.001), have joint contractures (OR 1.8, P = 0.05) and have higher physical disability as defined by scleroderma HAQ (OR 1.4, P = 0.01). CONCLUSION: The highest percentage of silica exposure was found in males. These patients were more likely to have the presence of certain clinical manifestations and Scl-70 antibody, which is known to confer a poor prognosis. These findings support the association between occupational silica exposure and the subsequent development of SSc. Further investigation is required to describe the range of clinical manifestations and disease course, including prognosis and treatment response, in those diagnosed with occupationally induced SSc compared with idiopathic SSc.

Significance of anti-neutrophil cytoplasmic antibodies in systemic sclerosis.

BACKGROUND: Up to 12% of patients with systemic sclerosis (SSc) have anti-neutrophil cytoplasmic antibodies (ANCA). However, the majority of these patients do not manifest ANCA-associated vasculitis (AAV) and the significance of ANCA in these patients is unclear. The aim of this study is to determine the prevalence of ANCA in a well-characterised SSc cohort and to examine the association between ANCA and SSc clinical characteristics, other autoantibodies, treatments and mortality. METHODS: Clinical data were obtained from 5 centres in the Australian Scleroderma Cohort Study (ASCS). ANCA positive was defined as the presence of any one or combination of cytoplasmic ANCA (c-ANCA), perinuclear ANCA (p-ANCA), atypical ANCA, anti-myeloperoxidase (anti-MPO) or anti-proteinase-3 (anti-PR3). Associations of demographic and clinical features with ANCA were investigated by logistic or linear regression. Survival analysis was performed using Kaplan-Meyer curves and Cox regression models. RESULTS: Of 1303 patients, 116 (8.9%) were ANCA positive. Anti-PR3 was more common than anti-MPO (13.8% and 11.2% of ANCA-positive patients, respectively). Only 3 ANCA-positive patients had AAV. Anti-Scl-70 was more common in ANCA positive vs ANCA negative (25% vs 12.8%, p < 0.001), anti-MPO positive vs anti-MPO negative (38.5% vs 13.6%, p = 0.006) and anti-PR3 positive vs anti-PR3 negative patients (44.4% vs 13.4%, p < 0.001). A higher prevalence of interstitial lung disease (ILD) was found in the ANCA positive (44.8% vs 21.8%, p < 0.001) and the anti-PR3 positive groups (50.0% vs 23.4%, p = 0.009). In multivariable analysis, ANCA-positive status remained associated with ILD after adjusting for anti-Scl-70 antibodies. Pulmonary embolism (PE) was more common in ANCA-positive patients (8.6% vs 3.0%, p = 0.002) and anti-PR3-positive patients (16.7% vs 3.3%, p = 0.022). ANCA-positive status remained associated with PE in a multivariable analysis adjusting for anti-phospholipid antibodies. Kaplan-Meier analysis revealed increased mortality in ANCA-positive patients (p = 0.006). In Cox regression analysis, ANCA was associated with increased mortality, after adjusting for age and sex. CONCLUSIONS: ANCA is associated with increased prevalence of ILD and PE in SSc. ANCA should be tested in SSc, as it identifies individuals with worse prognosis who require close monitoring for adverse outcomes.

Improving life expectancy of patients with scleroderma: results from the South Australian Scleroderma Register.

BACKGROUND: Scleroderma is a rare connective tissue disorder characterised by inflammation, vasculopathy and excessive fibrosis. Patients with scleroderma are known to have decreased life expectancy. AIM: To investigate changes in life expectancy in patients with scleroderma over a 30-year period. METHODS: Utilising the South Australian Scleroderma Register, deceased patients were identified. We examined changes in age of death and duration of disease in these patients over three time periods: 1985-1994, 1995-2004 and 2005-2015. Analyses of scleroderma subtypes were performed, and comparisons were made to the general South Australian population. RESULTS: A total of 413 deceased patients was identified. Females were overrepresented 315 to 98; 265 had limited scleroderma, 90 diffuse and 22 overlap disease. Over 30 years, the mean age of death improved from 66.4 to 74.5 years (P < 0.001). Duration of disease improved from 12.1 to 22.9 years (P < 0.001). Improvement in survival was seen in limited (P = 0.001), diffuse (P = 0.04) and overlap (P = 0.04) subgroups. The increase in survival was only seen for female (9.8 ± 4.2 years) but not male (1.4 ± 6.7 years) patients. CONCLUSION: Over the last 30 years, survival has significantly improved for female but not male patients. As no disease-modifying drugs have consistently been shown to alter disease course, this improvement is likely attributable to general improvements in medical care, including that of scleroderma-related complications. While the life expectancy for limited disease is now close to that of the general population, patients with diffuse and overlap disease continue to suffer from significant early mortality.

The role of nailfold capillary dropout on mortality in systemic sclerosis.

BACKGROUND: Semi-quantitative wide-field nailfold capillaroscopy (NFC) is a simple technique with proven utility in the early diagnosis of systemic sclerosis (SSc). Its role in prognosis, however, remains uncertain. AIM: To investigate the possible utility of NFC in predicting survival. METHODS: Patients with SSc listed on the South Australian Scleroderma Register (SASR) with prior NFC performed at Flinders Medical Centre from 1991 to 2015 were included in this study. Baseline demographic data, diagnosis, scleroderma antibody status and mortality status were also collected for each patient. RESULTS: The cohort consisted of 99 patients with limited cutaneous SSc, 30 patients with diffuse cutaneous SSc and 23 with an overlap scleroderma syndrome. Fifty-six patients died during the period of study (censured end June 2015). Patients with diffuse scleroderma had significantly greater capillary dropout compared with limited and overlap scleroderma (P < 0.001). In univariate analysis, both capillary dropout scores (log-rank χ2 = 8.75, P = 0.003) and antibody status (log-rank χ2 = 13.94, P = 0.003) were associated with mortality. ANOVA showed a significant association between antibody status and capillary dropout (P < 0.001). In Cox regression, adjustment for capillary dropout attenuated the impact of autoantibody group on survival. CONCLUSIONS: Nailfold capillary dropout was significantly associated with mortality and the severity of dropout attenuates survival dictated by antibody status. Together these observations support the hypothesis that capillary dropout is on the causal pathway between induction of scleroderma associated autoantibodies and mortality.

Educating children and families about growth hormone deficiency and its management: part 2.

Growth hormone deficiency (GHD) is a long-term condition, therefore creating ongoing partnerships with families is a fundamental part of the role of a paediatric endocrine nurse specialist (PENS). Teaching children, young people and their families about GHD and exploring what it means to them and how they can manage their ongoing treatment is central to building positive relationships. Educating children about the management of their growth hormone treatment (GHT) is an ongoing process and professionals must respond to the changing needs for that information children may have as they grow and develop. Long-term relationships with families are strengthened by recognising and respecting the developing expertise of families as they gain confidence and competence to manage GHT. This article is the second of two parts. Part one was published in the February issue of Nursing Children and Young People and covered an overview of growth hormone, causes and clinical presentation of GHD, development and availability of GHT and the role of the PENS in building partnerships with parents. The focus of this article is the education role of the PENS and the importance of providing information that is appropriate to the child or young person's developmental age.

Health professionals' experiences of tuberculosis cohort audit in the North West of England: a qualitative study.

OBJECTIVES: Tuberculosis cohort audit (TBCA) was introduced across the North West (NW) of England in 2012 as an ongoing, multidisciplinary, systematic case review process, designed to improve clinical and public health practice. TBCA has not previously been introduced across such a large and socioeconomically diverse area in England, nor has it undergone formal, qualitative evaluation. This study explored health professionals' experiences of the process after 1515 cases had been reviewed. DESIGN: Qualitative study using semistructured interviews. Respondents were purposively sampled from 3 groups involved in the NW TBCA: (1) TB nurse specialists, (2) consultant physicians and (3) public health practitioners. Data from the 26 respondents were triangulated with further interviews with key informants from the TBCA Steering Group and through observation of TBCA meetings. ANALYSIS: Interview transcripts were analysed thematically using the framework approach. RESULTS: Participants described the evolution of a valuable 'community of practice' where interprofessional exchange of experience and ideas has led to enhanced mutual respect between different roles and a shared sense of purpose. This multidisciplinary, regional approach to TB cohort audit has promoted local and regional team working, exchange of good practices and local initiatives to improve care. There is strong ownership of the process from public health professionals, nurses and clinicians; all groups want it to continue. TBCA is regarded as a tool for quality improvement that improves patient safety. CONCLUSIONS: TBCA provides peer support and learning for management of a relatively rare, but important infectious disease through discussion in a no-blame atmosphere. It is seen as an effective quality improvement strategy which enhances TB care, control and patient safety. Continuing success will require increased engagement of consultant physicians and public health practitioners, a secure and ongoing funding stream and establishment of clear reporting mechanisms within the public health system.

Educating children and families about growth hormone deficiency and its management: part 1.

The management of growth hormone deficiency is long term. Children may be diagnosed at pre-school age meaning relationships with the paediatric endocrine team may last more than 15 years. The education role of the paediatric endocrine nurse specialist is essential in working in partnership with families over a long period of time. Children and young people have changing needs for information to help them understand their condition and growth hormone deficiency treatment as they grow up. Developing positive working relationships with parents, children and young people enables their developmental needs and the context in which they live their lives to be central to any educational planning for them. Addressing developmental needs when providing information on growth hormone deficiency to children and young people reinforces the need for education to be an ongoing process and not a one-off event. This is part one of a two-part article. The second part will be published in the March issue of Nursing Children and Young People and it focuses on educating children, young people and their parents about the condition, and includes case studies.

Serum SmD autoantibody proteomes are clonally restricted and share variable-region peptides.

Recent advances in mass spectrometry-based proteomic methods have allowed variable (V)-region peptide signatures to be derived from human autoantibodies present in complex serum mixtures. Here, we analysed the clonality and V-region composition of immunoglobulin (Ig) proteomes specific for the immunodominant SmD protein subunit of the lupus-specific Sm autoantigen. Precipitating SmD-specific IgGs were eluted from native SmD-coated ELISA plates preincubated with sera from six patients with systemic lupus erythematosus (SLE) positive for anti-Sm/RNP. Heavy (H)- and light (L)-chain clonality and V-region sequences were analysed by 2-dimensional gel electrophoresis and combined de novo database mass spectrometric sequencing. SmD autoantibody proteomes from all six patients with SLE expressed IgG1 kappa restricted clonotypes specified by IGHV3-7 and IGHV1-69 H-chains and IGKV3-20 and IGKV2-28 L-chains, with shared and individual V-region amino acid replacement mutations. Clonotypic sharing and restricted V-region diversity of systemic autoimmunity can now be extended from the Ro/La cluster to Sm autoantigen and implies a common pathway of anti-Sm autoantibody production in unrelated patients with SLE.

Physical activity habits and preferences in the month prior to a first-ever stroke.

Background. Physical inactivity is a powerful risk factor for stroke and other chronic diseases. The aim of this study was to explore physical activity habits and preferences in the month leading up to a first-ever stroke, and to determine whether participants were aware of the link between stroke and physical activity. Methods. We undertook an observational study with 81 participants recently admitted to a stroke unit. Participants reported their pre-morbid physical activity preferences and habits and completed the Barriers to Physical Activity and Disability Survey. Data were analysed with summative content analysis and descriptive statistics. Results. Only 31% of participants were aware that physical inactivity was associated with stroke. Most participants defined physical activity with examples of instrumental activities of daily living (IADL) and walking (48% of responses), and IADLs constituted their most frequent regular physical activity (38% of responses). The barriers to physical activity reported by participants most frequently were lack of motivation (52%), lack of interest (50%) and lack of energy (42%). Conclusions. Regular physical activity is important to prevent stroke and other chronic diseases but adults at risk of stroke have little awareness of the risks of physical inactivity and little motivation to undertake regular exercise.

Surgical complications after immediate nephrectomy versus preoperative chemotherapy in non-metastatic Wilms' tumour: findings from the 1991-2001 United Kingdom Children's Cancer Study Group UKW3 Trial.

PURPOSE: To compare surgical complication rates after immediate nephrectomy versus delayed nephrectomy following preoperative chemotherapy in children with non-metastatic Wilms' tumour enrolled in UKW3, both in randomised patients and in those for whom the treatment approach was defined by parental or physician choice. METHODS: Records for all patients enrolled into UKW3 were reviewed. Any record of tumour rupture or surgical complication was extracted and comparisons made between the two treatment strategies in both populations of randomised and non-randomised patients. RESULTS: Of 525 children enrolled, 205 patients were randomised to either immediate nephrectomy (n=103) or pre-operative chemotherapy followed by delayed nephrectomy (n=102). Of the 320 children not randomised, data were available on 189 cases treated with immediate nephrectomy and 103 treated with pre-operative chemotherapy. There were significantly fewer surgical complications in randomised children given pre-operative chemotherapy before surgery compared to children undergoing immediate nephrectomy (1% vs. 20.4%, P<0.001); this difference was most marked for tumour rupture (0% vs. 14.6%, P<0.001). CONCLUSIONS: Delayed nephrectomy for Wilms' tumour, preceded by pre-operative chemotherapy was associated with fewer surgical complications compared with immediate nephrectomy.

Age and ethnic differences in volumetric breast density in new zealand women: a cross-sectional study.

Breast cancer incidence differs by ethnicity in New Zealand (NZ) with Maori (the indigenous people) women having the highest rates followed by Pakeha (people primarily of British/European descent), Pacific and Asian women, who experience the lowest rates. The reasons for these differences are unclear. Breast density, an important risk factor for breast cancer, has not previously been studied here. We used an automated system, Volpara™, to measure breast density volume from the medio-lateral oblique view of digital mammograms, by age (≤50 years and >50 years) and ethnicity (Pakeha/Maori/Pacific/Asian) using routine data from the national screening programme: age; x-ray system and mammography details for 3,091 Pakeha, 716 Maori, 170 Pacific and 662 Asian (total n = 4,239) women. Linear regression of the natural logarithm of absolute and percent density values was used, back-transformed and expressed as the ratio of the geometric means. Covariates were age, x-ray system and, for absolute density, the natural log of the volume of non-dense tissue (a proxy for body mass index). Median age for Pakeha women was 55 years; Maori 53 years; and Pacific and Asian women, 52 years. Compared to Pakeha women (reference), Maori had higher absolute volumetric density (1.09; 95% confidence interval [95% CI] 1.03-1.15) which remained following adjustment (1.06; 95% CI 1.01-1.12) and was stronger for older compared to younger Maori women. Asian women had the greatest risk of high percentage breast density (1.35; 95% CI 1.27-1.43) while Pacific women in both the ≤50 and >50 year age groups (0.78; 95% CI 0.66-0.92 and 0.81; 95% CI 0.71-0.93 respectively) had the lowest percentage breast density compared to Pakeha. As well as expected age differences, we found differential patterns of breast density by ethnicity consistent with ethnic differences seen in breast cancer risk. Breast density may be a contributing factor to NZ's well-known, but poorly explained, inequalities in breast cancer incidence.