Multiple Fibroblast Subtypes Contribute to Matrix Deposition in Pulmonary Fibrosis

Progressive pulmonary fibrosis results from a dysfunctional tissue repair response and is characterized by fibroblast proliferation, activation, and invasion and extracellular matrix accumulation. Lung fibroblast heterogeneity is well recognized. With single-cell RNA sequencing, fibroblast subtypes have been reported by recent studies. However, the roles of fibroblast subtypes in effector functions in lung fibrosis are not well understood. In this study, we incorporated the recently published single-cell RNA-sequencing datasets on murine lung samples of fibrosis models and human lung samples of fibrotic diseases and analyzed fibroblast gene signatures. We identified and confirmed the novel fibroblast subtypes we reported recently across all samples of both mouse models and human lung fibrotic diseases, including idiopathic pulmonary fibrosis, systemic sclerosis-associated interstitial lung disease, and coronavirus disease (COVID-19). Furthermore, we identified specific cell surface proteins for each fibroblast subtype through differential gene expression analysis, which enabled us to isolate primary cells representing distinct fibroblast subtypes by flow cytometry sorting. We compared matrix production, including fibronectin, collagen, and hyaluronan, after profibrotic factor stimulation and assessed the invasive capacity of each fibroblast subtype. Our results suggest that in addition to myofibroblasts, lipofibroblasts and Ebf1+ (Ebf transcription factor 1+) fibroblasts are two important fibroblast subtypes that contribute to matrix deposition and also have enhanced invasive, proliferative, and contraction phenotypes. The histological locations of fibroblast subtypes are identified in healthy and fibrotic lungs by these cell surface proteins. This study provides new insights to inform approaches to targeting lung fibroblast subtypes to promote the development of therapeutics for lung fibrosis.

Linkage of NAMPT promoter variants to eNAMPT secretion, plasma eNAMPT levels, and ARDS severity

BACKGROUND AND OBJECTIVES

eNAMPT (extracellular nicotinamide phosphoribosyltransferase), a novel DAMP and TLR4 ligand, is a druggable ARDS therapeutic target with NAMPT promoter SNPs associated with ARDS severity. This study assesses the previously unknown influence of NAMPT promoter SNPs on NAMPT transcription, eNAMPT secretion, and ARDS severity.

METHODS AND DESIGN

Human lung endothelial cells (ECs) transfected with NAMPT promoter luciferase reporters harboring SNPs G-1535A, A-1001 C, and C-948A, were exposed to LPS or LPS/18% cyclic stretch (CS) and NAMPT promoter activity, NAMPT protein expression, and secretion assessed. NAMPT genotypes and eNAMPT plasma measurements (Days 0/7) were assessed in two ARDS cohorts (DISCOVERY n = 428; ALVEOLI n = 103).

RESULTS

Comparisons of minor allelic frequency (MAF) in both ARDS cohorts with the 1000 Human Genome Project revealed the G-1535A and C-948A SNPs to be significantly associated with ARDS in Blacks compared with controls and trended toward significance in non-Hispanic Whites. LPS-challenged and LPS/18% CS-challenged EC harboring the -1535G wild-type allele exhibited significantly increased NAMPT promoter activity (compared with -1535A) with the -1535G/-948A diplotype exhibiting significantly increased NAMPT promoter activity, NAMPT protein expression, and eNAMPT secretion compared with the -1535A/-948 C diplotype. Highly significant increases in Day 0 eNAMPT plasma values were observed in both DISCOVERY and ALVEOLI ARDS cohorts (compared with healthy controls). Among subjects surviving to Day 7, Day 7 eNAMPT values were significantly increased in Day 28 non-survivors versus survivors. The protective -1535A SNP allele drove -1535A/-1001A and -1535A/-948 C diplotypes that confer significantly reduced ARDS risk (compared with -1535G, -1535G/-1001 C, -1535G/-948A), particularly in Black ARDS subjects. NAMPT SNP comparisons within the two ARDS cohorts did not identify significant association with either APACHE III scores or plasma eNAMPT levels.

CONCLUSION

NAMPT SNPs influence promoter activity, eNAMPT protein expression/secretion, plasma eNAMPT levels, and ARDS severity. NAMPT genotypes are a potential tool for stratification in eNAMPT-focused ARDS clinical trials.

A cortactin CTTN coding SNP contributes to lung vascular permeability and inflammatory disease severity in African descent subjects

The cortactin gene (CTTN), encoding an actin-binding protein critically involved in cytoskeletal dynamics and endothelial cell (EC) barrier integrity, contains single nucleotide polymorphisms (SNPs) associated with severe asthma in Black patients. As loss of lung EC integrity is a major driver of mortality in the Acute Respiratory Distress Syndrome (ARDS), sepsis, and the acute chest syndrome (ACS), we speculated CTTN SNPs that alter EC barrier function will associate with clinical outcomes from these types of conditions in Black patients. In case-control studies, evaluation of a nonsynonymous CTTN coding SNP Ser484Asn (rs56162978, G/A) in a severe sepsis cohort (725 Black subjects) revealed significant association with increased risk of sepsis mortality. In a separate cohort of sickle cell disease (SCD) subjects with and without ACS (177 SCD Black subjects), significantly increased risk of ACS and increased ACS severity (need for mechanical ventilation) was observed in carriers of the A allele. Human lung EC expressing the cortactin S484N transgene exhibited: (i) delayed EC barrier recovery following thrombin-induced permeability; (ii) reduced levels of critical Tyr486 cortactin phosphorylation; (iii) inhibited binding to the cytoskeletal regulator, nmMLCK; and (iv) attenuated EC barrier-promoting lamellipodia dynamics and biophysical responses. ARDS-challenged Cttn+/- heterozygous mice exhibited increased lung vascular permeability (compared to wild-type mice) which was significantly attenuated by IV delivery of liposomes encargoed with CTTN WT transgene but not by CTTN S484N transgene. In summary, these studies suggest that the CTTN S484N coding SNP contributes to severity of inflammatory injury in Black patients, potentially via delayed vascular barrier restoration.

Abnormal respiratory progenitors in fibrotic lung injury

Recent advances in single-cell RNA sequencing (scRNA-seq) and epithelium lineage labeling have yielded identification of multiple abnormal epithelial progenitor populations during alveolar type 2 (ATII) cell differentiation into alveolar type 1 (ATI) cells during regenerative lung post-fibrotic injury. These abnormal cells include basaloid/basal-like cells, ATII transition cells, and persistent epithelial progenitors (PEPs). These cells occurred and accumulated during the regeneration of distal airway and alveoli in response to both chronic and acute pulmonary injury. Among the alveolar epithelial progenitors, PEPs express a distinct Krt8⁺ phenotype that is rarely found in intact alveoli. However, post-injury, the Krt8⁺ phenotype is seen in dysplastic epithelial cells. Fully understanding the characteristics and functions of these newly found, injury-induced abnormal behavioral epithelial progenitors and the signaling pathways regulating their phenotype could potentially point the way to unique therapeutic targets for fibrosing lung diseases. This review summarizes recent advances in understanding these epithelial progenitors as they relate to uncovering regenerative mechanisms.

Transcriptomics of bronchoalveolar lavage cells identifies new molecular endotypes of sarcoidosis

BACKGROUND

Sarcoidosis is a multisystem granulomatous disease of unknown origin with a variable and often unpredictable course and pattern of organ involvement. In this study we sought to identify specific bronchoalveolar lavage (BAL) cell gene expression patterns indicative of distinct disease phenotypic traits.

METHODS

RNA sequencing by Ion Torrent Proton was performed on BAL cells obtained from 215 well-characterised patients with pulmonary sarcoidosis enrolled in the multicentre Genomic Research in Alpha-1 Antitrypsin Deficiency and Sarcoidosis (GRADS) study. Weighted gene co-expression network analysis and nonparametric statistics were used to analyse genome-wide BAL transcriptome. Validation of results was performed using a microarray expression dataset of an independent sarcoidosis cohort (Freiburg, Germany; n=50).

RESULTS

Our supervised analysis found associations between distinct transcriptional programmes and major pulmonary phenotypic manifestations of sarcoidosis including T-helper type 1 (Th1) and Th17 pathways associated with hilar lymphadenopathy, transforming growth factor-β1 (TGFB1) and mechanistic target of rapamycin (MTOR) signalling with parenchymal involvement, and interleukin (IL)-7 and IL-2 with airway involvement. Our unsupervised analysis revealed gene modules that uncovered four potential sarcoidosis endotypes including hilar lymphadenopathy with increased acute T-cell immune response; extraocular organ involvement with PI3K activation pathways; chronic and multiorgan disease with increased immune response pathways; and multiorgan involvement, with increased IL-1 and IL-18 immune and inflammatory responses. We validated the occurrence of these endotypes using gene expression, pulmonary function tests and cell differentials from Freiburg.

CONCLUSION

Taken together, our results identify BAL gene expression programmes that characterise major pulmonary sarcoidosis phenotypes and suggest the presence of distinct disease molecular endotypes.

The acute respiratory distress syndrome biomarker pipeline: crippling gaps between discovery and clinical utility

Recent innovations in translational research have ushered an exponential increase in the discovery of novel biomarkers, thereby elevating the hope for deeper insights into "personalized" medicine approaches to disease phenotyping and care. However, a critical gap exists between the fast pace of biomarker discovery and the successful translation to clinical use. This gap underscores the fundamental biomarker conundrum across various acute and chronic disorders: how does a biomarker address a specific unmet need? Additionally, the gap highlights the need to shift the paradigm from a focus on biomarker discovery to greater translational impact and the need for a more streamlined drug approval process. The unmet need for biomarkers in acute respiratory distress syndrome (ARDS) is for reliable and validated biomarkers that minimize heterogeneity and allow for stratification of subject selection for enrollment in clinical trials of tailored therapies. This unmet need is particularly highlighted by the ongoing SARS-CoV-2/COVID-19 pandemic. The unprecedented numbers of COVID-19-induced ARDS cases has strained health care systems across the world and exposed the need for biomarkers that would accelerate drug development and the successful phenotyping of COVID-19-infected patients at risk for development of ARDS and ARDS mortality. Accordingly, this review discusses the current state of ARDS biomarkers in the context of the drug development pipeline and highlight gaps between biomarker discovery and clinical implementation while proposing potential paths forward. We discuss potential ARDS biomarkers by category and by context of use, highlighting progress in the development continuum. We conclude by discussing challenges to successful translation of biomarker candidates to clinical impact and proposing possible novel strategies.

Direct Extracellular NAMPT Involvement in Pulmonary Hypertension and Vascular Remodeling. Transcriptional Regulation by SOX and HIF-2α

We previously demonstrated involvement of NAMPT (nicotinamide phosphoribosyltransferase) in pulmonary arterial hypertension (PAH) and now examine NAMPT regulation and extracellular NAMPT's (eNAMPT's) role in PAH vascular remodeling. NAMPT transcription and protein expression in human lung endothelial cells were assessed in response to PAH-relevant stimuli (PDGF [platelet-derived growth factor], VEGF [vascular endothelial growth factor], TGF-β1 [transforming growth factor-β1], and hypoxia). Endothelial-to-mesenchymal transition was detected by SNAI1 (snail family transcriptional repressor 1) and PECAM1 (platelet endothelial cell adhesion molecule 1) immunofluorescence. An eNAMPT-neutralizing polyclonal antibody was tested in a PAH model of monocrotaline challenge in rats. Plasma eNAMPT concentrations, significantly increased in patients with idiopathic pulmonary arterial hypertension, were highly correlated with indices of PAH severity. eNAMPT increased endothelial-to-mesenchymal transition, and each PAH stimulus significantly increased endothelial cell NAMPT promoter activity involving transcription factors STAT5 (signal transducer and activator of transcription 5), SOX18 (SRY-box transcription factor 18), and SOX17 (SRY-box transcription factor 17), a PAH candidate gene newly defined by genome-wide association study. The hypoxia-induced transcription factor HIF-2α (hypoxia-inducible factor-2α) also potently regulated NAMPT promoter activity, and HIF-2α binding sites were identified between -628 bp and -328 bp. The PHD2 (prolyl hydroxylase domain-containing protein 2) inhibitor FG-4592 significantly increased NAMPT promoter activity and protein expression in an HIF-2α-dependent manner. Finally, the eNAMPT-neutralizing polyclonal antibody significantly reduced monocrotaline-induced vascular remodeling, PAH hemodynamic alterations, and NF-κB activation. eNAMPT is a novel and attractive therapeutic target essential to PAH vascular remodeling.

BAL Cell Gene Expression Is Indicative of Outcome and Airway Basal Cell Involvement in Idiopathic Pulmonary Fibrosis

RATIONALE

Idiopathic pulmonary fibrosis (IPF) is a fatal disease with a variable and unpredictable course.

OBJECTIVES

To determine whether BAL cell gene expression is predictive of survival in IPF.

METHODS

This retrospective study analyzed the BAL transcriptome of three independent IPF cohorts: Freiburg (Germany), Siena (Italy), and Leuven (Belgium) including 212 patients. BAL cells from 20 healthy volunteers, 26 patients with sarcoidosis stage III and IV, and 29 patients with chronic obstructive pulmonary disease were used as control subjects. Survival analysis was performed by Cox models and component-wise boosting. Presence of airway basal cells was tested by immunohistochemistry and flow cytometry.

MEASUREMENTS AND MAIN RESULTS

A total of 1,582 genes were predictive of mortality in the IPF derivation cohort in univariate analyses adjusted for age and sex at false discovery rate less than 0.05. A nine-gene signature, derived from the discovery cohort (Freiburg), performed well in both replication cohorts, Siena (P < 0.0032) and Leuven (P = 0.0033). nCounter expression analysis confirmed the array results (P < 0.0001). The genes associated with mortality in BAL cells were significantly enriched for genes expressed in airway basal cells. Further analyses by gene expression, flow cytometry, and immunohistochemistry showed an increase in airway basal cells in BAL and tissues of IPF compared with control subjects, but not in chronic obstructive pulmonary disease or sarcoidosis.

CONCLUSIONS

Our results identify and validate a BAL signature that predicts mortality in IPF and improves the accuracy of outcome prediction based on clinical parameters. The BAL signature associated with mortality unmasks a potential role for airway basal cells in IPF.

Development of a biomarker mortality risk model in acute respiratory distress syndrome

Background

There is a compelling unmet medical need for biomarker-based models to risk-stratify patients with acute respiratory distress syndrome. Effective stratification would optimize participant selection for clinical trial enrollment by focusing on those most likely to benefit from new interventions. Our objective was to develop a prognostic, biomarker-based model for predicting mortality in adult patients with acute respiratory distress syndrome.

Methods

This is a secondary analysis using a cohort of 252 mechanically ventilated subjects with the diagnosis of acute respiratory distress syndrome. Survival to day 7 with both day 0 (first day of presentation) and day 7 sample availability was required. Blood was collected for biomarker measurements at first presentation to the intensive care unit and on the seventh day. Biomarkers included cytokine-chemokines, dual-functioning cytozymes, and vascular injury markers. Logistic regression, latent class analysis, and classification and regression tree analysis were used to identify the plasma biomarkers most predictive of 28-day ARDS mortality.

Results

From eight biologically relevant biomarker candidates, six demonstrated an enhanced capacity to predict mortality at day 0. Latent-class analysis identified two biomarker-based phenotypes. Phenotype A exhibited significantly higher plasma levels of angiopoietin-2, macrophage migration inhibitory factor, interleukin-8, interleukin-1 receptor antagonist, interleukin-6, and extracellular nicotinamide phosphoribosyltransferase (eNAMPT) compared to phenotype B. Mortality at 28 days was significantly higher for phenotype A compared to phenotype B (32% vs 19%, p = 0.04).

Conclusions

An adult biomarker-based risk model reliably identifies ARDS subjects at risk of death within 28 days of hospitalization.

Genomic and Genetic Approaches to Deciphering Acute Respiratory Distress Syndrome Risk and Mortality

Significance: Acute respiratory distress syndrome (ARDS) is a severe, highly heterogeneous critical illness with staggering mortality that is influenced by environmental factors, such as mechanical ventilation, and genetic factors. Significant unmet needs in ARDS are addressing the paucity of validated predictive biomarkers for ARDS risk and susceptibility that hamper the conduct of successful clinical trials in ARDS and the complete absence of novel disease-modifying therapeutic strategies. Recent Advances: The current ARDS definition relies on clinical characteristics that fail to capture the diversity of disease pathology, severity, and mortality risk. We undertook a comprehensive survey of the available ARDS literature to identify genes and genetic variants (candidate gene and limited genome-wide association study approaches) implicated in susceptibility to developing ARDS in hopes of uncovering novel biomarkers for ARDS risk and mortality and potentially novel therapeutic targets in ARDS. We further attempted to address the well-known health disparities that exist in susceptibility to and mortality from ARDS. Critical Issues: Bioinformatic analyses identified 201 ARDS candidate genes with pathway analysis indicating a strong predominance in key evolutionarily conserved inflammatory pathways, including reactive oxygen species, innate immunity-related inflammation, and endothelial vascular signaling pathways. Future Directions: Future studies employing a system biology approach that combines clinical characteristics, genomics, transcriptomics, and proteomics may allow for a better definition of biologically relevant pathways and genotype-phenotype connections and result in improved strategies for the sub-phenotyping of diverse ARDS patients via molecular signatures. These efforts should facilitate the potential for successful clinical trials in ARDS and yield a better fundamental understanding of ARDS pathobiology.

Validation of a 52-gene risk profile for outcome prediction in patients with idiopathic pulmonary fibrosis: an international, multicentre, cohort study

BACKGROUND

The clinical course of idiopathic pulmonary fibrosis (IPF) is unpredictable. Clinical prediction tools are not accurate enough to predict disease outcomes.

METHODS

We enrolled patients with IPF diagnosis in a six-cohort study at Yale University (New Haven, CT, USA), Imperial College London (London, UK), University of Chicago (Chicago, IL, USA), University of Pittsburgh (Pittsburgh, PA, USA), University of Freiburg (Freiburg im Breisgau, Germany), and Brigham and Women's Hospital-Harvard Medical School (Boston, MA, USA). Peripheral blood mononuclear cells or whole blood were collected at baseline from 425 participants and from 98 patients (23%) during 4-6 years' follow-up. A 52-gene signature was measured by the nCounter analysis system in four cohorts and extracted from microarray data (GeneChip) in the other two. We used the Scoring Algorithm for Molecular Subphenotypes (SAMS) to classify patients into low-risk or high-risk groups based on the 52-gene signature. We studied mortality with a competing risk model and transplant-free survival with a Cox proportional hazards model. We analysed timecourse data and response to antifibrotic drugs with linear mixed effect models.

FINDINGS

The application of SAMS to the 52-gene signature identified two groups of patients with IPF (low-risk and high-risk), with significant differences in mortality or transplant-free survival in each of the six cohorts (hazard ratio [HR] range 2·03-4·37). Pooled data showed similar results for mortality (HR 2·18, 95% CI 1·53-3·09; p<0·0001) or transplant-free survival (2·04, 1·52-2·74; p<0·0001). Adding 52-gene risk profiles to the Gender, Age, and Physiology index significantly improved its mortality predictive accuracy. Temporal changes in SAMS scores were associated with changes in forced vital capacity (FVC) in two cohorts. Untreated patients did not shift their risk profile over time. A simultaneous increase in up score and decrease in down score was predictive of decreased transplant-free survival (3·18, 1·16-8·76; p=0·025) in the Pittsburgh cohort. A simultaneous decrease in up score and increase in down score after initiation of antifibrotic drugs was associated with a significant (p=0·0050) improvement in FVC in the Yale cohort.

INTERPRETATION

The peripheral blood 52-gene expression signature is predictive of outcome in patients with IPF. The potential value of the 52-gene signature in predicting response to therapy should be determined in prospective studies.

FUNDING

The Pulmonary Fibrosis Foundation, the Harold Amos Medical Faculty Development Program of the Robert Wood Johnson Foundation, and the National Heart, Lung, and Blood Institute of the US National Institutes of Health.

A feasibility study of behavioural activation for depressive symptoms in adults with intellectual disabilities

BACKGROUND

Important work has been carried out adapting cognitive behavioural therapy for people with intellectual disabilities. However, there is a lack of alternative psychological therapies available for people with intellectual disabilities and emotional difficulties. Behavioural activation for depression is less reliant on verbal communication and focuses on increasing purposeful activity and reducing avoidance.

METHOD

This feasibility study involved the development and piloting of an adapted manual of behavioural activation for people with intellectual disabilities. The intervention consisted of 10-12 sessions and a key adaptation was that the therapist worked with the clients alongside a significant other in their life, either a paid carer or family member. Baseline, post-intervention (3 months after entering the study) and 6-month quantitative follow-up data were obtained. Primary outcome data were gathered, concerning depressive symptoms, participants' levels of activity and general well-being.

RESULTS

Twenty-three adults with intellectual disabilities with symptoms of depression were recruited from specialist health services. In terms of acceptability, the behavioural activation intervention was well received and only two individuals dropped out, with a further two lost to follow-up. The main measures of depression appeared to be sensitive to change. Pre- to post-intervention data showed a significant reduction in self-report of depressive symptoms with a strong effect size (r = 0.78), that was maintained at follow-up (r = 0.86). Positive change was also obtained for informant reports of depressive symptoms from pre- to post-intervention, with a strong effect size (r = 0.7). Once again, this positive change was maintained at follow-up (r = 0.72).

CONCLUSIONS

The study suggested that behavioural activation may be a feasible and worthwhile approach to tackling depression in people with intellectual disabilities. However, a randomised controlled trial would be required to establish its effectiveness, with more sensitive measurement of change in activity.

Self-perceived social status and health in older Hong Kong Chinese women compared with men

Economic and social factors are determinants of health, as are psychosocial factors. The present study compared self-perceived social status and its relation to health, health related quality of life and lifestyle in older women with men, adjusting for age, education level and maximum lifetime income. A cross-sectional study was conducted of 4,000 men and women aged 65 years and over in a community in the North Eastern part of Hong Kong, a Special Administrative Region in China. Participants were asked to rate their community status, education, income and occupation, on two ladders, each with ten rungs. The distributions of the two ladder scores differed, showing that although participants may not have been ranked highly in terms of money, education and job respectability, they may have ranked their community standing highly. Women and older participants tended to rank their community standing highly in spite of lower ratings in the objective measures. A social gradient in self-perceived social status, independent of objective socioeconomic measures, was noted for physical performance and health-related quality of life, rather than related to presence of specific chronic diseases or lifestyle. However, the different ratings of the two ladders suggested that mechanisms by which the gradient operates may differ between women and men. Further studies are needed to explore the health and psychosocial consequences of the gender difference in self-rated social status.

Nutrient intake and psychological health in an elderly Chinese population

BACKGROUND

Associations between nutrition and cognitive impairment, and nutrition and depression, have been observed. Elderly people are at risk of under nutrition, and also have higher prevalence of cognitive impairment and depression.

OBJECTIVE

To examine the relationship between nutrient intake and psychological health in the elderly, adjusting for confounding factors.

SUBJECTS

Three thousand nine hundred and ninety-nine men and women aged 65 years and over living in the community, with approximately equal numbers in three age groups: 65-69, 70-74, 75+ years.

METHODS

Dietary intake was assessed using a 7-day food frequency questionnaire. Cognitive function was assessed by the cognitive part of the Community Screening Instrument for Dementia (CSID). Depression was assessed using the Geriatric Depression Scale (GDS). Information was also collected for confounding factors: demographics, educational level, socioeconomic status, medical history, smoking, alcohol intake, and physical activity. Logistic regression analyses were carried out to examine associations between lifestyle and dietary variables, and CSID and GDS, controlling for confounders.

RESULTS

Both CSID and GDS scores were associated with co-morbidity, demographic and socioeconomic factors. Few associations between lifestyle factors and CSID score were observed. Dietary factors inversely associated with GDS score include total fat intake, vitamins A, B2, B3, C, fibre, and vegetables. In terms of nutrient density, iron and isoflavone intake were additional factors.

CONCLUSION

Association exists between intake of various nutrients and psychological health independent of other confounding factors in the elderly population. A follow-up study of this cohort or interventional studies are needed to elucidate cause effect relationship.

Angiotensin converting enzyme inhibitor use is associated with higher bone mineral density in elderly Chinese

Hypertension and osteoporosis are two major chronic diseases affecting the elderly. A cross-sectional study of 3887 Chinese men (n = 1958) and women (n = 1929) was used to explore the association between angiotensin converting enzyme inhibitor (ACEI) use and bone mineral density (BMD). The participants were aged 65 years and above, and were recruited using a combination of private solicitation and public advertising from community centers, housing estates, and the general community in Hong Kong. Demographic, medical, and lifestyle information was obtained from face to face interviews using standardized questionnaire, and physical examination measurements included anthropometry, tibial, and brachial systolic blood pressures, femoral neck, total hip, and lumbar spine BMD. In multiple regression analyses, after adjusting for age, weight, height, thiazide, beta-blocker, calcium channel blocker, statin, corticosteroid, and calcium supplement use, history of diabetes, heart disease, peripheral vascular disease, cigarette smoking, alcohol intake, and physical activity level, ACEI use was associated with higher femoral neck BMD (+0.015 g/cm2, P = 0.035) in women, and higher femoral neck (+0.015 g/cm2, P = 0.017), total hip (+0.016 g/cm2, P = 0.021), and lumbar spine (+0.043 g/cm2, P < 0.001) BMD in men. Thiazide use was associated with higher BMD at all three sites in general, although associations with BMD increase at the total hip (P = 0.07) and femoral neck (P = 0.09) were weak in men. Calcium channel blocker use was only significantly associated with BMD increase at the lumbar spine (P = 0.03) in women, and beta-blocker use did not have significant associations with BMD at any site. This study suggests that in addition to thiazide diuretics ACEI may have possible benefits in treating not only hypertension but also osteoporosis among older Chinese.

The determinants of bone mineral density in Chinese men--results from Mr. Os (Hong Kong), the first cohort study on osteoporosis in Asian men

Mr. Os (Hong Kong) is the first study to address the risk factors for osteoporosis in Asian men. A standardized, structured interview and dual X-ray densitometry (DEXA) were performed on 2,000 Chinese men aged 65-92. By multiple regression, the following factors were found to be positively associated with BMD at both the total hip and the spine: body weight, grip strength and a history of diabetes mellitus. The following factors were found to be negatively associated with BMD at both the total hip and spine: cigarette smoking, a history of gastrectomy or bowel resection, current use of inhaled steroid and a history of fracture after 50 years. Moreover, a history of chronic obstructive pulmonary disease (COPD) was negatively associated with BMD at the total hip, and age, the use of an alpha-blocker, thiazide diuretic and nitrate were associated with a higher BMD at the spine. A total of 21.8% of the variance in total hip and 31.5% of the variance in total spine BMD was accounted for in the multivariate analysis.

Bone mineral density and the risk of peripheral arterial disease in men and women: results from Mr. and Ms Os, Hong Kong

Previous population studies have demonstrated an association between peripheral vascular disease and bone mineral density in women, but not in men. In a large prospective cohort of 3,998 Chinese men and women aged 65 to 92 years of age in Hong Kong, the association between peripheral vascular disease and bone mineral density was explored. Demographic and lifestyle information was obtained from face to face interviews using a standardized questionnaire. This included demographic information, medical history and lifestyle factors. Physical examination measurements included anthropometry and tibial and brachial systolic blood pressures. The ratio of the posterior tibial and brachial systolic blood pressures, the ankle/arm index, was used as a measure of peripheral arteriosclerosis in the lower extremities. Bone mineral density (BMD) at the total hip and spine (L1-L4) was measured by Hologic QDR-4500 W densitometers (Hologic, Inc., Waltham, Mass.). In this cross-sectional analysis, the ankle brachial index (ABI) was positively correlated with hip BMD (correlation coefficient=0.27; P<0.001). However, after adjustment for confounders, the correlation became much weaker (correlation coefficient=0.03; P<0.05). This showed that much of the relationship between ABI and BMD could be explained by other confounders. In multiple regression analysis, an increase in ABI of 1 SD of ABI was associated with an increase of 0.5% (95% CI: 0.02%, 0.9%) in hip BMD after adjusting for age, sex, body weight, smoking status, history of diabetes, cardiovascular diseases, use of thiazide diuretics, grip strength and physical activity. Although our study shows that peripheral vascular disease in the lower extremities may be associated with decreased bone mineral density, the association is weak especially after adjustment was made for confounders. This indicates that other factors may be contributing to the association between peripheral vascular disease and osteoporosis.

Correlates for a low ankle-brachial index in elderly Chinese

This study examines the prevalence of atherosclerosis (using ankle-brachial index (ABI) value <0.9) and associated socioeconomic and lifestyle factors in elderly Chinese, adjusting for presence of cardiovascular diseases and body mass index, in a cross-sectional survey of 1999 men and 1999 women aged 65 years and over living in the community. A questionnaire containing information regarding socioeconomic status, medical history and lifestyle factors was administered. Measurement included height, weight, percentage body fat using dual-energy X-ray absorptiometry and ABI. The Hong Kong population (2000) age adjusted prevalence of ABI <0.9 was 5.3% for men and 11.0% for women. In multivariate analysis, old age, female gender, presence of cardiovascular diseases, cognitive impairment, prolonged 6 m walk, smoking habit and alcohol intake were positively associated with ABI <0.9, while negative associations were observed with Vitamin C intake >100 mg per day, with the lowest OR for the range 141-190 mg (OR 0.4). Physical activity level, and self rated higher social standing in the community, while significant in univariate analysis, were not included as independent significant factors in the multivariate model. Lifestyle factors and the female gender were independent risk factors for atherosclerosis in the elderly Chinese population.

Benefits of milk powder supplementation on bone accretion in Chinese children

Low dietary calcium intake has been demonstrated to be a risk factor for hip and vertebral fractures in studies conducted among Hong Kong Chinese. Few studies have demonstrated the effect of milk supplementation in bone accretion in Chinese children. The aim was to examine the effects of milk powder supplementation in enhancing bone accretion in Chinese children. Three hundred and forty-four children, aged 9-10 years old, were randomized to receive milk powder equivalent to 1300 mg and 650 mg calcium, and to a control group, respectively. Bone mineral density (BMD) at the proximal femur, lumbar spine and total body were measured at 6 months, 12 months and 18 months. The treatment effects were modeled using linear mixed effect models and compared using linear contrast F-tests, by intention-to-treat. Subjects randomized to milk powder equivalent to 1300 mg calcium had significantly higher increase in BMD at both the total hip (7.4 +/- 0.4% in treatment group versus 6.3 +/- 0.4% in the control) and the spine (8.4 +/- 0.5% in the treatment group versus 7.0 +/- 0.5% in the control group). Subjects randomized to milk powder equivalent to 650 mg calcium had smaller increases in BMD at the total hip and spine, although the increase in BMD at the total body was significantly higher (3.1 +/- 0.3% in treatment group versus 2.4 +/- 0.2% in controls). It is concluded that supplementing the diet of Chinese children with milk powder was effective in enhancing bone accretion.

The epidemiology of cigarette smoking in Hong Kong Chinese women

BACKGROUND

Smoking in women is a well-recognized public health problem. In many developed countries, cigarette smoking is now the single most important preventable cause of premature death in women. There are relatively few data on the epidemiology of cigarette smoking in Asian women, and this study examined the prevalence of and factors predisposing Chinese women to smoke cigarettes in Hong Kong.

METHOD

A territory-wide random telephone survey of 26,716 households in Hong Kong was conducted. A total of 1064 current smokers and 291 ex-smokers were identified in these household, and in-depth interviews of 791 current smokers, 221 ex-smokers, and 1012 controls were conducted.

RESULTS

The prevalence of cigarette smoking was 4.5% in women who were 25 years or younger, 2.6% in women aged 46-65 years, and 2.2% in women aged 65 years or older. Sixty-four percent of current smokers started when they were 19 years or younger. The main reasons for the initiation of cigarette smoking were the influence of friends, curiosity, feeling bored, or being idle. Current smokers and ex-smokers tended to have positive images of women who smoked. The following risk factors were found to be significant for cigarette smoking: less than university education, unemployment, being divorced, having a husband who smoked, and a low score on the perceived harms of cigarette smoking.

CONCLUSION

Cigarette smoking is more prevalent in younger women in Hong Kong; and psychosocial issues should be addressed to prevent future epidemics.

Surveillance of infectious complications associated with central venous access devices in children with haemophilia

PURPOSE

To analyse the risk factors for infection associated with central venous access device (CVAD) use in children with haemophilia.

METHODS

Risk factors for CVAD infection among patients with congenital haemophilia who had had a CVAD implanted at a single institution were evaluated utilizing the following variables: age at CVAD placement, age at end of study, number of days with a CVAD, percentage of lifetime with a CVAD, and history of inhibitor.

RESULTS

Fifty-nine patients had a total of 97,936 (median 1768 days per patient) CVAD days in the study period. The median age at CVAD placement was 2.7 years (range 0-14.0). Twenty-six (44%) patients reported CVAD infections during the study period from January 1993 to October 2000. Twenty-four patients had their CVAD replaced, 17 (71%) of whom reported having infections and seven (29%) of whom had a history of inhibitor. The strongest predictor for having any infections was inhibitor status (P=0.16), although none of the risk factors had statistically significant effects. Among the 26 patients reporting infections, 42% had more than one CVAD-related infection. Seven patients had multiple infections involving the same organism. The mean rate of infection was 0.45 per 1000 catheter days, with a 95% confidence interval of 0.33-0.60. Those with a history of inhibitor had an infection rate of 0.66 compared with 0.38 per 1000 catheter days (P=0.09) for those without a history of inhibitor. Patients who were older (greater than the median age of 2.7) at CVAD placement had a lower rate of infection (0.29 vs. 0.65, P<0.01) compared with those < or =2.7 years. Adjustment for inhibitor status had little impact on these results. For the group as a whole, the median time to first infection was 1977 days from CVAD placement. Patients who were older at CVAD placement or study exit had lower relative hazards of infection (P=0.05 and P=0.09 respectively), while those who had inhibitors had a higher but not statistically significant relative hazard of 1.88 (P=0.13).

CONCLUSIONS

These data reveal that while considerable numbers of patients develop CVAD-related infection, the interval between catheter placement and infection can be quite long. In addition, the earlier in life a CVAD is placed, the higher the risk of infectious complications, as evidenced by the tendency towards a higher infection rate. Measures to prevent CVAD-related infection might be focused on very young patients who appear to be at higher risk.

Areal and volumetric bone density in Hong Kong Chinese: a comparison with Caucasians living in the United States

It is a common perception that Asians have lower bone density than Caucasians. However, such relationships could be confounded by bone size. In this study, the skeletal status of a convenience sample of 482 men and 887 women living in Hong Kong is compared with published data for Caucasians living in Rochester, Minnesota. Areal bone mineral density (BMD, g/cm(2)) and volumetric bone mineral apparent density (BMAD, g/cm(3)) were determined for the lumbar spine and proximal femur, using the Hologic QDR 2000 instrument. Cross-calibration was performed by measuring a common phantom, and the Hong Kong data were adjusted by a multiplication factor. Lumbar spine and femoral neck BMD and BMAD of Chinese men and women were all significantly lower ( P<0.001 by t-test) than those of Caucasians, but the differences in BMAD were on average only about half the size of the differences in BMD. For instance, in postmenopausal Chinese women, BMD at the femoral neck and lumbar spine were 15.2% and 18.8% lower respectively, but BMAD at the femoral neck and lumbar spine were only 7.8% and 12.4% lower respectively. Similar trends were observed in men. After adjusting for age, body height and weight, the difference in BMAD between Caucasians and Chinese was further reduced and only statistically significant among postmenopausal women and among men younger than age 50 years for the lumbar spine. For instance, the adjusted BMAD in postmenopausal Chinese women at the femoral neck and lumbar spine were 3.9% ( P=0.03 by ANCOVA) and 7.3% ( P<0.001 by ANCOVA) lower respectively, while the adjusted BMAD at the lumbar spine for Chinese men younger than 50 years was 11.7% lower ( P<0.01 by ANCOVA). Predictors of BMAD in Hong Kong Chinese women include body weight, age at menarche, cigarette smoking, and oral contraceptive use ( P<0.001), while body weight was the only independent predictor of BMAD in Hong Kong Chinese men ( P<0.001). We conclude that bone density is lower in Hong Kong Chinese men and women than in Caucasians, although such differences were attenuated by adjustments for bone size, body weight and height.

Milk supplementation prevents bone loss in postmenopausal Chinese women over 3 years

Previously published results from a 2 year randomized, controlled clinical trial on supplementing the diet of postmenopausal Chinese women with high-calcium milk powder (containing 800 mg of calcium) showed that bone loss, as measured by bone mineral density (BMD), was prevented. To determine whether the effect of calcium supplementation could be sustained, the study was extended for 1 additional year. According to the intention-to-treat analysis, the differences in the rate of bone loss (percentage decrease in control group--percentage decrease in milk supplementation group) in the third year of the study were: total body BMD, 0.23% (95% confidence interval [CI] 0.07%-0.39%); total spine BMD, 0.31% (95% CI - 0.02%-0.65%); and total hip BMD, 0.44% (95% CI 0.19%-0.69%). Analysis by the per-protocol method showed a similar effect size. These results indicate that the effects of milk supplementation in preventing bone loss in postmenopausal Chinese women were sustained after 2 years.

Effects of physical interventions on house dust mite allergen levels in carpet, bed, and upholstery dust in low-income, urban homes

House dust mite allergen exposure is a postulated risk factor for allergic sensitization, asthma development, and asthma morbidity; however, practical and effective methods to mitigate these allergens from low-income, urban home environments remain elusive. The purpose of this study was to assess the feasibility and effectiveness of physical interventions to mitigate house dust mite allergens in this setting. Homes with high levels of house dust mite allergen (Der f 1 + Der p 1 > or = 10 microg/g dust by enzyme-linked immunosorbent assay) in the bed, bedroom carpet, and/or upholstered furniture were enrolled in the study. Carpets and upholstered furniture were subjected to a single treatment of either dry steam cleaning plus vacuuming (carpet only) or intensive vacuuming alone. Bed interventions consisted of complete encasement of the mattress, box spring, and pillows plus either weekly professional or in-home laundering of nonencased bedding. Dust samples were collected at baseline and again at 3 days (carpet and upholstery only) and 2, 4, and 8 weeks posttreatment. We compared pretreatment mean allergen concentrations and loads to posttreatment values and performed between-group analyses after adjusting for differences in the pretreatment means. Both dry steam cleaning plus vacuuming and vacuuming alone resulted in a significant reduction in carpet house dust mite allergen concentration and load (p < 0.05). Levels approached pretreatment values by 4 weeks posttreatment in the intensive vacuuming group, whereas steam cleaning plus vacuuming effected a decrease that persisted for up to 8 weeks. Significant decreases in bed house dust mite allergen concentration and load were obtained in response to encasement and either professional or in-home laundering (p < 0.001). Between-group analysis revealed significantly less postintervention house dust mite allergen load in professionally laundered compared to home-laundered beds (p < 0.05). Intensive vacuuming and dry steam cleaning both caused a significant reduction in allergen concentration and load in upholstered furniture samples (p < 0.005). Based on these data, we conclude that physical interventions offer practical, effective means of reducing house dust mite allergen levels in low-income, urban home environments.

Physician-based activity counseling: intervention effects on mediators of motivational readiness for physical activity

In theory-based interventions for behavior change, there is a need to examine the effects of interventions on the underlying theoretical constructs and the mediating role of such constructs. These two questions are addressed in the Physically Active for Life study, a randomized trial of physician-based exercise counseling for older adults. Three hundred fifty-five patients participated (intervention n = 181, control n = 174; mean age = 65.6 years). The underlying theories used were the Transtheoretical Model, Social Cognitive Theory and the constructs of decisional balance (benefits and barriers), self-efficacy, and behavioral and cognitive processes of change. Motivational readiness for physical activity and related constructs were assessed at baseline, 6 weeks, and 8 months. Linear or logistic mixed effects models were used to examine intervention effects on the constructs, and logistic mixed effects models were used for mediator analyses. At 6 weeks, the intervention had significant effects on decisional balance, self-efficacy, and behavioral processes, but these effects were not maintained at 8 months. At 6 weeks, only decisional balance and behavioral processes were identified as mediators of motivational readiness outcomes. Results suggest that interventions of greater intensity and duration may be needed for sustained changes in mediators and motivational readiness for physical activity among older adults.

Relation between HIV-1 and hepatitis C viral load in patients with hemophilia

Coinfection with hepatitis C virus (HCV) and HIV-1 is common in patients with hemophilia and in intravenous drug users. Little, however, is known about the relation between HIV-1 and HCV coinfection and the effects on HCV clearance and pathogenesis. We examined data from 207 HIV-1-infected and 126 HIV-1-uninfected patients with hemophilia enrolled in the multicenter Hemophilia Growth and Development Study. Participants were observed during prospective follow-up for approximately 7 years with annual measurements of alanine aminotransferase (ALT), CD4+ cells, and HCV and HIV-1 RNA levels. Clearance of HCV was more likely to occur in those uninfected with HIV-1 (14.3 versus 2.5%; odds ratio [OR] 4.79; 95% confidence interval [CI], 1.63-14.08, p =.005) and was more common with decreasing age (OR, 1.23; 95% CI, 1.04-1.47; p =.017). HCV RNA levels were higher throughout the 7 years of follow-up in those HIV-1-infected (p <.001). In the HIV-1-infected participants, baseline CD4+ cells were inversely related to HCV RNA with every 100-cell increase associated with a 0.19 log10 copy/ml decrease in HCV RNA (p =.002), and HIV-1 and HCV RNA levels were directly related (p =.008). Increasing HCV RNA levels were also associated with significantly higher ALT levels regardless of HIV-1 infection status. These results demonstrate that HIV-1/HCV co-infection is associated with a reduced likelihood of HCV clearance and that higher levels of HCV RNA are associated with increased hepatic inflammation.

Hepatitis C virus load is associated with human immunodeficiency virus type 1 disease progression in hemophiliacs

Hepatitis C virus (HCV) and human immunodeficiency virus type 1 (HIV-1) coinfection is common in hemophiliacs and injection drug users. To assess the interaction between HCV load and HIV-1 disease progression, we examined 207 HIV-1/HCV-coinfected patients. Patients were followed prospectively for approximately 7 years, and annual measurements of CD4(+) cell counts and HCV and HIV-1 loads were obtained. Survival analysis was used to define the independent effects of HCV load on HIV-1 progression. After controlling for CD4(+) cell count and HIV-1 RNA level, every 10-fold increase in baseline HCV RNA was associated with a relative risk (RR) for clinical progression to acquired immunodeficiency syndrome (AIDS) of 1.66 (95% confidence interval [CI], 1.10-2.51; P=.016) and an RR for AIDS-related mortality of 1.54 (95% CI, 1.03-2.30; P=.036). These findings emphasize the need for further research regarding the use of HIV-1- and HCV-specific therapy in coinfected individuals.

Do obese inner-city children with asthma have more symptoms than nonobese children with asthma?

OBJECTIVE

To test whether obesity is associated with decreased peak expiratory flow rates (PEFR), increased asthma symptoms, and increased health service use.

DESIGN/METHODS

Secondary analysis of data from a cross-sectional convenience sample.

SETTING

Emergency departments (EDs) and primary care clinics in 8 inner-city areas in 7 cities.

PARTICIPANTS

One thousand three hundred twenty-two children aged 4 to 9 years with asthma.

MEASURES

Obesity was defined as a body mass index (BMI, weight/height(2)) >95th percentile. Nonobese children were those with a BMI between the 5th and 95th percentile. Underweight children with a BMI <5th percentile were eliminated from the study. Demographic and anthropometric data were obtained during a baseline interview with the primary caretaker and the child. Symptoms, health service use data and measurements of PEFR were obtained by parental report during the baseline interview and at 3-month intervals by telephone interview over the following 9-month period.

RESULTS

Obese (n = 249) and nonobese (n = 1073) children did not differ in terms of age, gender, family income, passive smoke exposure, caretaker's mental health, and skin test reactivity to indoor allergens. Obese children were more often Latino (28% vs 17%) and, in the 3 months before the baseline interview, were more likely to have used oral steroids (30% vs 24%). There were no differences between groups in terms of baseline PEFR scores. During the 9 months after baseline assessment, the obese group had a higher mean number of days of wheeze per 2-week period (4.0 vs 3.4), and a greater proportion of obese individuals had unscheduled ED visits (39% vs 31%). There were no differences between the groups in terms of frequency of hospitalization, or in nocturnal awakening.

CONCLUSIONS

In our sample of inner-city children with asthma, obese children used more medicine, wheezed more, and a greater proportion had unscheduled ED visits than the nonobese children.

Cognitive-behavioral predictors of asthma morbidity in inner-city children

Asthma is a growing health problem among children in the United States, particularly in urban, inner-city areas. This article examines the relationship between cognitive-behavioral aspects of asthma management (caretaker asthma knowledge, expectations, and problem-solving) and asthma morbidity in a sample of 1,376 inner-city children with physician-diagnosed asthma. In the analyses, baseline symptom severity served as a covariate, and the average of the 3-, 6-, and 9-month follow-up data served as the outcome measure. Children of caregivers with ineffective problem-solving strategies had significantly more days of wheezing over a 14-day period. Ineffective problem-solving capabilities were also associated with poorer functional status; however, positive caregiver expectations were associated with better functional status. Of the cognitive-behavioral factors studied in a high-risk urban population, caregiver problem-solving skills and expectations emerged as meriting further investigation and possible intervention.

The relationship between psychosocial factors and asthma morbidity in inner-city children with asthma

OBJECTIVE

Children living in the inner city are affected disproportionately by asthma morbidity and mortality. Previous research has shown that behavioral and psychosocial factors affect asthma morbidity in children. The National Cooperative Inner-City Asthma Study investigated the factors that contribute to asthma morbidity among inner-city children. This article examines the relationship between psychosocial factors and asthma morbidity in this population.

METHODS

A total of 1528 English- and Spanish-speaking children 4 to 9 years of age with asthma and their primary caretakers were recruited from 8 research centers in 7 metropolitan inner-city areas in the United States. Psychosocial variables were assessed at baseline and included measures of child and caretaker mental health, caretaker's problems with alcohol, life stress, social support, and parenting style. Morbidity measures were evaluated at baseline and at 3-, 6-, and 9-month follow-up intervals. These included number of hospitalizations and unscheduled visits for asthma in the past 3 months and number of days of wheeze and functional status in the previous 2-week period.

RESULTS

Of the psychosocial variables assessed, mental health had the strongest relationship to children's asthma morbidity. Children whose caretakers had clinically significant levels of mental health problems were hospitalized for asthma at almost twice the rate as children whose caretakers did not have significant mental health problems. Children with clinically significant behavior problems had significantly more days of wheeze and poorer functional status in the follow-up period.

CONCLUSION

Psychosocial factors, particularly the mental health of children and caretakers, are significant factors in predicting asthma morbidity. They may need to be included in intervention programs aimed at decreasing asthma morbidity in inner-city children with asthma in order for these programs to be successful.

Effects of plasma HIV RNA, CD4+ T lymphocytes, and the chemokine receptors CCR5 and CCR2b on HIV disease progression in hemophiliacs. Hemophilia Growth and Development Study

We have investigated the effects of plasma HIV RNA, CD4+ T lymphocytes and chemokine receptors CCR5 and CCR2b on HIV disease progression in hemophiliacs. We prospectively observed during follow-up 207 HIV-infected hemophiliacs in the Hemophilia Growth and Development Study. Plasma HIV RNA was measured on cryopreserved plasma from enrollment using the Chiron Corporation bDNA (version 2.0) assay. Genoytpe variants CCR2b-641 and CCR5-delta32 were detected using standard molecular techniques. Those with the mutant allele for CCR2b, and to a lesser extent CCR5, had lower plasma HIV RNA, and higher CD4+ T lymphocytes than did those without these genetic variants. After controlling for the effects of plasma HIV RNA and CD4+ T lymphocytes, those with the CCR2b mutant allele compared with those wild-type, had a trend toward a lower risk of progression to AIDS, adjusted relative hazard of 1.94 (95% confidence interval [CI], 0.9-4.18; p = .092), and AIDS-related death, relative hazard 1.97 (95% CI, 0.98-4.00; p = .059). We conclude that plasma HIV RNA, CD4+ T lymphocytes, and CCR genotypes are correlated, and the protective affect of CCR2b against HIV disease progression is not completely explained by plasma HIV RNA or CD4+ T-lymphocyte number.

Relationship of indoor allergen exposure to skin test sensitivity in inner-city children with asthma

BACKGROUND

It is important to understand the relationship between environmental allergen exposure dose and the risk of atopic individuals becoming sensitized to that allergen if we are to change the risk of sensitization and morbidity from allergic disease.

OBJECTIVE

The objective of these studies was to determine whether there was a dose response between current exposure to mite, cockroach, and cat allergen in inner-city children and to determine the prevalence of sensitization to these allergens.

METHODS

A sample of 500 children was selected from the 1528 children enrolled in the National Cooperative Inner City Asthma Study. Children were selected who had a sample of home dust and valid skin test responses performed with a MultiTest skin test device. The samples of home dust were collected from the floor and furniture in the kitchen, bedroom, and television/living room and were assayed for Der p 1, Der f 1, Bla g 1, and Fel d 1 allergens.

RESULTS

Each allergen level correlated significantly between rooms in individual homes. Mite (Der p 1 and Der f 1) and cat (Fel d 1) allergen levels were frequently below the detection limit of the assay. Cockroach allergen (Bla g 1) concentrations in the child's bedroom were related to the prevalence of positive skin test responses to cockroach allergen extract among the children, with an odds ratio for sensitization of 1.45 (1.11-1.92). Positive skin test responses to cockroach allergen were seen in 15% of children exposed to bedroom dust with a Bla g 1 concentration below the level of detection compared with a rate of 32% in bedrooms with Bla g 1 levels of 1 to 2 U/g and 40% to 44% among those in rooms with 4 U/g or greater. The relationship between exposure and positive skin test responses was clearly stronger among atopic children with a greater number of positive skin test responses.

CONCLUSIONS

Despite widespread exposure to household allergens, the strongest relationship between exposure and sensitization was seen in the bedroom. The dose response between exposure to cockroach allergen and sensitization suggested that exposure to low doses of allergen, 2 U/g or less, was a risk factor and that the risk plateaus above 4 U/g. Atopy modified the relationship of exposure to sensitization.

Reported difficulties in access to quality care for children with asthma in the inner city

OBJECTIVE

To characterize perceived access and barriers to quality health care for asthma among the caregivers of children in the inner city.

DESIGN

Multicenter, cross-sectional survey.

SETTING

Eight sites in 7 major metropolitan US inner cities.

PARTICIPANTS

A systematic sample of children with asthma, aged 4 to 9 years, and their caregivers who resided in census tracts in which at least 30% of the households were below the 1990 federal poverty guidelines, recruited from 25 primary care clinics and 13 emergency departments (EDs) from November 1, 1992, through October 31, 1993.

RESULTS

Of the 1528 children enrolled, 1376 had physician-diagnosed asthma and form the basis of this report. This group was further divided into 284 children (20.6%) who met all recruitment criteria for severe asthma and 207 (15.0%) with mild asthma who met none. Of parents in the total sample, 95.6% reported a usual place for short-term asthma care for their child; 75.4% used the ED. Children with severe asthma were significantly more likely to use the ED than those with mild asthma (84.3% vs 63.0%; P<.01). A usual place for follow-up asthma care was reported by 96.7% of subjects. There were no differences in access or type of facility used by asthma severity. More than half the study group reported difficulty in accessing care for acute asthma attacks and for follow-up care with no differences by asthma severity. Among those with severe asthma, 47.5% used inhaled steroids or cromolyn, 52.8% used a spacer device if they had been prescribed a metered dose inhaler, and 21.2% of children older than 6 years were prescribed a peak flowmeter. Patients with mild asthma were significantly less likely to report use of all 3 items (steroids or cromolyn, 1.4%; spacer device, 15.4%; and peak flowmeter, 3.1%, respectively; P<.01).

CONCLUSION

Although access to asthma care among children in US inner cities appears adequate as determined by the traditional measure of reporting a regular source of care, barriers are frequently reported, as are deficiencies in the quality of medical care.

Longitudinal neurological follow-up of a group of HIV-seropositive and HIV-seronegative hemophiliacs: results from the hemophilia growth and development study

BACKGROUND

Boys and young men with hemophilia treated with factor infusions before 1985 had a substantial risk of acquiring the human immunodeficiency virus (HIV) and the acquired immunodeficiency syndrome. This study was designed to assess the effects of HIV and hemophilia per se on neurological function in a large cohort of subjects with hemophilia, and to investigate the relationships between neurological disease and death during follow-up.

METHODS

Three hundred thirty-three boys and young men (207 HIV seropositive and 126 HIV seronegative) were evaluated longitudinally in a multicenter, multidisciplinary study. Neurological history and examination were conducted at baseline and annually for 4 years. The relationship between neurological variables, HIV serostatus, CD4+ cell counts, and vital status at the conclusion of the study was examined using logistic regression models.

RESULTS

The risks of nonhemophilia-associated muscle atrophy, behavior change, and gait disturbance increased with time in immune compromised HIV-seropositive subjects compared with HIV seronegative or immunologically stable HIV-seropositive subjects. The risk of behavior change in immune compromised HIV-seropositive hemophiliacs, for example, rose to 60% by year 4 versus 10% to 17% for the other study groups. Forty-five subjects (13.5%), all of whom were HIV seropositive, died by year 4. Subjects who died had had increased risks of hyperreflexia, nonhemophilia-associated muscle atrophy, and behavior change.

CONCLUSIONS

These results indicate that immune compromised, HIV-seropositive hemophiliacs have high rates of neurological abnormalities over time and that neurological abnormalities were common among subjects who later died. By contrast, immunologically stable HIV-seropositive subjects did not differ from the HIV-seronegative participants. Hemophilia per se was associated with progressive abnormalities of gait, coordination, and motor function.

The role of cockroach allergy and exposure to cockroach allergen in causing morbidity among inner-city children with asthma

BACKGROUND

It has been hypothesized that asthma-related health problems are most severe among children in inner-city areas who are allergic to a specific allergen and also exposed to high levels of that allergen in bedroom dust.

METHODS

From November 1992 through October 1993, we recruited 476 children with asthma (age, four to nine years) from eight inner-city areas in the United States. Immediate hypersensitivity to cockroach, house-dust-mite, and cat allergens was measured by skin testing. We then measured major allergens of cockroach (Bla g 1), dust mites (Der p 1 and Der f 1), and cat dander (Fel d 1) in household dust using monoclonal-antibody-based enzyme-linked immunosorbent assays. High levels of exposure were defined according to proposed thresholds for causing disease. Data on morbidity due to asthma were collected at base line and over a one-year period.

RESULTS

Of the children, 36.8 percent were allergic to cockroach allergen, 34.9 percent to dust-mite allergen, and 22.7 percent to cat allergen. Among the children's bedrooms, 50.2 percent had high levels of cockroach allergen in dust, 9.7 percent had high levels of dust-mite allergen, and 12.6 percent had high levels of cat allergen. After we adjusted for sex, score on the Child Behavior Checklist, and family history of asthma, we found that children who were both allergic to cockroach allergen and exposed to high levels of this allergen had 0.37 hospitalization a year, as compared with 0.11 for the other children (P=0.001), and 2.56 unscheduled medical visits for asthma per year, as compared with 1.43 (P<0.001). They also had significantly more days of wheezing, missed school days, and nights with lost sleep, and their parents or other care givers were awakened during the night and changed their daytime plans because of the child's asthma significantly more frequently. Similar patterns were not found for the combination of allergy to dust mites or cat dander and high levels of the allergen.

CONCLUSIONS

The combination of cockroach allergy and exposure to high levels of this allergen may help explain the frequency of asthma-related health problems in inner-city children.