Root development and function

Book Review

Root development and functionP.J. Gregory, J.V. Lake and D.A. Rose (Eds.), (Society for Experimental Biology Seminar Series 30). Cambridge University Press 1987. 206 pages. Price £20. ISBN 0-5213-2931-0     

The translation of lipid profiles to nutritional biomarkers in the study of infant metabolism

Introduction

Links between early life exposures and later health outcomes may, in part, be due to nutritional programming in infancy. This hypothesis is supported by observed long-term benefits associated with breastfeeding, such as better cognitive development in childhood, and lower risks of obesity and high blood pressure in later life. However, the possible underlying mechanisms are expected to be complex and may be difficult to disentangle due to the lack of understanding of the metabolic processes that differentiate breastfed infants compared to those receiving just formula feed.

Objective

Our aim was to investigate the relationships between infant feeding and the lipid profiles and to validate specific lipids in separate datasets so that a small set of lipids can be used as nutritional biomarkers.

Method

We utilized a direct infusion high-resolution mass spectrometry method to analyse the lipid profiles of 3.2 mm dried blood spot samples collected at age 3 months from the Cambridge Baby Growth Study (CBGS-1), which formed the discovery cohort. For validation two sample sets were profiled: Cambridge Baby Growth Study (CBGS-2) and Pregnancy Outcome Prediction Study (POPS). Lipidomic profiles were compared between infant groups who were either exclusively breastfed, exclusively formula-fed or mixed-fed at various levels. Data analysis included supervised Random Forest method with combined classification and regression mode. Selection of lipids was based on an iterative backward elimination procedure without compromising the class error in the classification mode.

Conclusion

From this study, we were able to identify and validate three lipids: PC(35:2), SM(36:2) and SM(39:1) that can be used collectively as biomarkers for infant nutrition during early development. These biomarkers can be used to determine whether young infants (3–6 months) are breast-fed or receive formula milk.

     

Molecular subtype classification is a determinant of non-sentinel lymph node metastasis in breast cancer patients with positive sentinel lymph nodes

Background

Previous studies suggested that the molecular subtypes were strongly associated with sentinel lymph node (SLN) status. The purpose of this study was to determine whether molecular subtype classification was associated with non-sentinel lymph nodes (NSLN) metastasis in patients with a positive SLN.

Methodology and Principal Findings

Between January 2001 and March 2011, a total of 130 patients with a positive SLN were recruited. All these patients underwent a complete axillary lymph node dissection. The univariate and multivariate analyses of NSLN metastasis were performed. In univariate and multivariate analyses, large tumor size, macrometastasis and high tumor grade were all significant risk factors of NSLN metastasis in patients with a positive SLN. In univariate analysis, luminal B subgroup showed higher rate of NSLN metastasis than other subgroup (P = 0.027). When other variables were adjusted in multivariate analysis, the molecular subtype classification was a determinant of NSLN metastasis. Relative to triple negative subgroup, both luminal A (P = 0.047) and luminal B (P = 0.010) subgroups showed a higher risk of NSLN metastasis. Otherwise, HER2 over-expression subgroup did not have a higher risk than triple negative subgroup (P = 0.183). The area under the curve (AUC) value was 0.8095 for the Cambridge model. When molecular subtype classification was added to the Cambridge model, the AUC value was 0.8475.

Conclusions

Except for other factors, molecular subtype classification was a determinant of NSLN metastasis in patients with a positive SLN. The predictive accuracy of mathematical models including molecular subtype should be determined in the future.     

Prospective Memory Performance in Non-Psychotic First-Degree Relatives of Patients with Schizophrenia: A Controlled Study

Objective

We aimed at investigating prospective memory and its socio-demographic and neurocognitive correlates in non-psychotic, first-degree relatives (FDRs) of patients with schizophrenia compared to patients with first episode schizophrenia (FES), and healthy controls (HCs).

Methods

Forty-seven FES patients, 50 non-psychotic FDRs (23 offspring and 27 siblings) of patients with chronic schizophrenia (unrelated to the FES group) and 51 HCs were studied. The Chinese version of the Cambridge Prospective Memory Test (C-CAMPROMPT) was used to measure time-based prospective memory (TBPM) and event-based prospective memory (EBPM) performance. Other cognitive functions (involving respective memory and executive functions) were evaluated with standardized tests.

Results

After controlling for basic demographic characteristics including age, gender and educational level, there was a significant difference between FDRs, FES and HCs with respect to both TBPM (F_(2,142) = 10.4, p<0.001) and EBPM (F_(2,142) = 10.8, p<0.001). Multiple linear regression analyses revealed that lower scores of the Hopkins Verbal Learning Test-Revised (HVLT-R) and the STROOP Word-Color Test (SWCT) contributed to TBPM impairment, while lower educational level and higher scores of the Color Trails Test-2 (CTT-2) contributed to EBPM deficit in FDRs.

Conclusions

FDRs share similar but attenuated prospective memory impairments with schizophrenia patients, suggesting that prospective memory deficits may represent an endophenotype of schizophrenia.     

A 28,000 years old Cro-Magnon mtDNA sequence differs from all potentially contaminating modern sequences

Background

DNA sequences from ancient speciments may in fact result from undetected contamination of the ancient specimens by modern DNA, and the problem is particularly challenging in studies of human fossils. Doubts on the authenticity of the available sequences have so far hampered genetic comparisons between anatomically archaic (Neandertal) and early modern (Cro-Magnoid) Europeans.

Methodology/Principal Findings

We typed the mitochondrial DNA (mtDNA) hypervariable region I in a 28,000 years old Cro-Magnoid individual from the Paglicci cave, in Italy (Paglicci 23) and in all the people who had contact with the sample since its discovery in 2003. The Paglicci 23 sequence, determined through the analysis of 152 clones, is the Cambridge reference sequence, and cannot possibly reflect contamination because it differs from all potentially contaminating modern sequences.

Conclusions/Significance:

The Paglicci 23 individual carried a mtDNA sequence that is still common in Europe, and which radically differs from those of the almost contemporary Neandertals, demonstrating a genealogical continuity across 28,000 years, from Cro-Magnoid to modern Europeans. Because all potential sources of modern DNA contamination are known, the Paglicci 23 sample will offer a unique opportunity to get insight for the first time into the nuclear genes of early modern Europeans.     

Neurological Soft Signs and Their Relationships to Neurocognitive Functions: A Re-Visit with the Structural Equation Modeling Design

Background

Neurological soft signs and neurocognitive impairments have long been considered important features of schizophrenia. Previous correlational studies have suggested that there is a significant relationship between neurological soft signs and neurocognitive functions. The purpose of the current study was to examine the underlying relationships between these two distinct constructs with structural equation modeling (SEM).

Methods

118 patients with schizophrenia and 160 healthy controls were recruited for the current study. The abridged version of the Cambridge Neurological Inventory (CNI) and a set of neurocognitive function tests were administered to all participants. SEM was then conducted independently in these two samples to examine the relationships between neurological soft signs and neurocognitive functions.

Results

Both the measurement and structural models showed that the models fit well to the data in both patients and healthy controls. The structural equations also showed that there were modest to moderate associations among neurological soft signs, executive attention, verbal memory, and visual memory, while the healthy controls showed more limited associations.

Conclusions

The current findings indicate that motor coordination, sensory integration, and disinhibition contribute to the latent construct of neurological soft signs, whereas the subset of neurocognitive function tests contribute to the latent constructs of executive attention, verbal memory, and visual memory in the present sample. Greater evidence of neurological soft signs is associated with more severe impairment of executive attention and memory functions. Clinical and theoretical implications of the model findings are discussed.     

Facial Identity Recognition in the Broader Autism Phenotype

Background

The ‘broader autism phenotype’ (BAP) refers to the mild expression of autistic-like traits in the relatives of individuals with autism spectrum disorder (ASD). Establishing the presence of ASD traits provides insight into which traits are heritable in ASD. Here, the ability to recognise facial identity was tested in 33 parents of ASD children.

Methodology and Results

In experiment 1, parents of ASD children completed the Cambridge Face Memory Test (CFMT), and a questionnaire assessing the presence of autistic personality traits. The parents, particularly the fathers, were impaired on the CFMT, but there were no associations between face recognition ability and autistic personality traits. In experiment 2, parents and probands completed equivalent versions of a simple test of face matching. On this task, the parents were not impaired relative to typically developing controls, however the proband group was impaired. Crucially, the mothers'' face matching scores correlated with the probands'', even when performance on an equivalent test of matching non-face stimuli was controlled for.

Conclusions and Significance

Components of face recognition ability are impaired in some relatives of ASD individuals. Results suggest that face recognition skills are heritable in ASD, and genetic and environmental factors accounting for the pattern of heritability are discussed. In general, results demonstrate the importance of assessing the skill level in the proband when investigating particular characteristics of the BAP.     

Fitting alignment tensor components to experimental RDCs,CSAs and RQCs

Residual dipolar couplings, chemical shift anisotropies and quadrupolar couplings provide information about the orientation of inter-spin vectors and the anisotropic contribution of the local environment to the chemical shifts of nuclei, respectively. Structural interpretation of these observables requires parameterization of their angular dependence in terms of an alignment tensor. We compare and evaluate two algorithms for generating the optimal alignment tensor for a given molecular structure and set of experimental data, namely SVD (Losonczi et al. in J Magn Reson 138(2):334–342, 1999), which scales as \({{\mathcal {O}}(n^2)}\), and the linear least squares algorithm (Press et al. in Numerical recipes in C. The art of scientific computing, 2nd edn. Cambridge University Press, Cambridge, 1997), which scales as \({{\mathcal {O}}(n)}\).     

Caregiver burden in amyotrophic lateral sclerosis is more dependent on patients’ behavioral changes than physical disability: a comparative study

Background

Behavioral changes in patients with amyotrophic lateral sclerosis (ALS) mirror those found in frontotemporal dementia (FTD). Considering the high rate of neuropsychiatric symptoms found in ALS patients, this paper examines whether caregiver burden is associated with behavioral changes over and above the physical disability of patients with ALS, and if the presence of caregivers’ depression, anxiety and stress also impacts on caregiver burden.

Methods

140 caregivers of patients with ALS participated in a postal survey investigating patients’ neuropsychiatric symptoms (Cambridge Behaviour Inventory Revised CBI-R), motor function (Amyotrophic Lateral Sclerosis Functional Rating Scale Revised - ALSFRS-R), caregiver burden (Zarit Burden Interview), and caregiver mood (Depression, Anxiety and Stress Scale- DASS21). Seventy four percent of them were caregivers of patients with limb onset and 25.7% were caregivers of patients with bulbar onset.

Results

Moderate to severe behavioral changes were reported in 10-40% of patients with ALS. The levels of depression, anxiety and stress in the caregivers reached 20%. Burden was high in 48% of the caregivers. The strongest predictor of high caregiver burden was ALS patients’ abnormal behavior rather than physical disability, with an odds ratio of 1.4, followed by caregivers’ stress.

Conclusions

Our study has identified that behavioral changes (e.g. disinhibition, impulsivity) and caregiver stress have greater impact on caregiver burden than level and pattern of physical disability.

     

Multiple Sclerosis Decreases Explicit Counterfactual Processing and Risk Taking in Decision Making

Introduction

Deficits in decision making (DM) are commonly associated with prefrontal cortical damage, but may occur with multiple sclerosis (MS). There are no data concerning the impact of MS on tasks evaluating DM under explicit risk, where different emotional and cognitive components can be distinguished.

Methods

We assessed 72 relapsing-remitting MS (RRMS) patients with mild to moderate disease and 38 healthy controls in two DM tasks involving risk with explicit rules: (1) The Wheel of Fortune (WOF), which probes the anticipated affects of decisions outcomes on future choices; and (2) The Cambridge Gamble Task (CGT) which measures risk taking. Participants also underwent a neuropsychological and emotional assessment, and skin conductance responses (SCRs) were recorded.

Results

In the WOF, RRMS patients showed deficits in integrating positive counterfactual information (p<0.005) and greater risk aversion (p<0.001). They reported less negative affect than controls (disappointment: p = 0.007; regret: p = 0.01), although their implicit emotional reactions as measured by post-choice SCRs did not differ. In the CGT, RRMS patients differed from controls in quality of DM (p = 0.01) and deliberation time (p = 0.0002), the latter difference being correlated with attention scores. Such changes did not result in overall decreases in performance (total gains).

Conclusions

The quality of DM under risk was modified by MS in both tasks. The reduction in the expression of disappointment coexisted with an increased risk aversion in the WOF and alexithymia features. These concomitant emotional alterations may have implications for better understanding the components of explicit DM and for the clinical support of MS patients.     

Survival of influenza A(H1N1) on materials found in households: implications for infection control

Background

The majority of influenza transmission occurs in homes, schools and workplaces, where many frequently touched communal items are situated. However the importance of transmission via fomites is unclear since few data exist on the survival of virus on commonly touched surfaces. We therefore measured the viability over time of two H1N1 influenza strains applied to a variety of materials commonly found in households and workplaces.

Methodology and Principal Findings

Influenza A/PuertoRico/8/34 (PR8) or A/Cambridge/AHO4/2009 (pandemic H1N1) viruses were inoculated onto a wide range of surfaces used in home and work environments, then sampled at set times following incubation at stabilised temperature and humidity. Virus genome was measured by RT-PCR; plaque assay (for PR8) or fluorescent focus formation (for pandemic H1N1) was used to assess the survival of viable virus.

Conclusions/Significance

The genome of either virus could be detected on most surfaces 24 h after application with relatively little drop in copy number, with the exception of unsealed wood surfaces. In contrast, virus viability dropped much more rapidly. Live virus was recovered from most surfaces tested four hours after application and from some non-porous materials after nine hours, but had fallen below the level of detection from all surfaces at 24 h. We conclude that influenza A transmission via fomites is possible but unlikely to occur for long periods after surface contamination (unless re-inoculation occurs). In situations involving a high probability of influenza transmission, our data suggest a hierarchy of priorities for surface decontamination in the multi-surface environments of home and hospitals.     

Evaluating the impact of point‐ of‐care decision support tools in improving diagnosis of obese children in primary care

Objective:

The purpose of this quasi‐experimental study was to examine the effect of a computerized point‐of‐care alert with clinical decision support on the rates of diagnosis of childhood obesity in a multisite group practice in Massachusetts; Cambridge Health Alliance (CHA) which implemented an alert, relative to a separate group practice, Harvard Vanguard Medical Associates (HVMA), that did not.

Design and Methods:

Height and weight data from 19,466 children of 2‐18 years with 34,908 well‐child care visits in CHA and 123,446 children with 282,271 visits in HVMA between 2006 and 2008 were collected. The alert and decision support tool was activated for CHA patients with an age‐ and sex‐specific body mass index of ≥95th percentile. The main outcome measure was documentation of an International Classification of Diseases, Ninth Revision [ICD‐9] code for obesity before and after implementation of the alert at CHA in 2007.

Results:

Among obese children, the adjusted rate of an ICD‐9 diagnosis of obesity increased from 2006‐2007 to 2008 significantly more at CHA than at HVMA (P < 0.001 for time‐by‐provider group interaction). In 2006‐2007, the rate of ICD‐9 diagnosis of obesity was significantly lower at CHA than at HVMA (adjusted odds ratio [OR]: 0.57; 95% confidence interval [CI]: 0.52‐0.62); but by 2008 was significantly higher at CHA than HVMA (adjusted OR: 1.25; 95% CI: 1.14‐1.38).

Conclusion:

A point‐of‐care alert was effective in improving obesity diagnosis in a multisite group practice, relative to a separate group practice that did not adopt an alert. Clinical decision support tools could help improve obesity diagnosis in pediatric primary care.     

Correlates of reported and recorded time spent in physical activity in working adults: results from the commuting and health in cambridge study

Background

The correlates of physical activity in adults are relatively well studied. However, many studies use self-reported (‘reported’) measures of activity and we know little about the possible differences between the correlates of reported and objective (‘recorded’) measures of physical activity. We compared the correlates of reported and recorded time spent in moderate-to-vigorous physical activity (MVPA) in a sample of working adults.

Methods

In 2009, participants in the Commuting and Health in Cambridge study completed questionnaires assessing individual, socio-demographic, health and contextual characteristics. Recorded time spent in MVPA over seven days was ascertained using accelerometers and reported time spent in MVPA was assessed using the Recent Physical Activity Questionnaire (RPAQ). Correlates of MVPA were investigated using sex-specific linear regression models.

Results

486 participants (70% women) provided both reported and recorded physical activity data. 89% recorded at least 30 minutes of MVPA per day. In men, none of the potential explanatory variables were associated with both reported and recorded time spent in MVPA. In women, of all the potential explanatory variables only that of having a standing or manual occupation was associated with both reported (+42 min/day; 95% CI 16.4 to 68.4, p = 0.001) and recorded (+9 min/day; 95% CI: 3.5 to 15.7, p = 0.002) time spent in MVPA.

Discussion

The use of an objective measure of physical activity may influence the correlates which are observed. Researchers may wish to consider using and analysing recorded and reported measures in combination to gain a more complete view of the correlates of physical activity.     

Barriers encountered during enrollment in an internet-mediated randomized controlled trial

Background

Research evidence from observational studies suggests that cognitive activity reduces the risk of cognitive impairment in later life as well as the rate of cognitive decline of people with dementia. The Promoting Healthy Ageing with Cognitive Exercise (PACE) study has been designed to determine whether a cognitive activity intervention decreases the rate of cognitive decline amongst older adults with mild cognitive impairment (MCI).

Methods/Design

The study will recruit 160 community-dwelling men and women aged 65 years of age or over with mild cognitive impairment (MCI). Participants will be randomly allocated to two treatment groups: non-specific education and cognitive activity. The intervention will consist of ten 90-minute sessions delivered twice per week over a period of five weeks. The primary outcome measure of the study is the change from baseline in the total score on the Cambridge Cognitive Score (CAMCOG). Secondary outcomes of interest include changes in memory, attention, executive functions, mood and quality of life. Primary endpoints will be collected 12, 52 and 104 weeks after the baseline assessment.

Discussion

The proposed project will produce the best available evidence on the merits of increased cognitive activity as a strategy to prevent cognitive decline among older adults with MCI. We anticipate that the results of this study will have implications for the development of evidence-based preventive strategies to reduce the rate of cognitive decline amongst older people at risk of dementia.

Trial registration

ACTRN12608000556347     

‘Like Playing a Game Where You Don't Know the Rules’: Investing Meaning in Intercultural Cash Transactions Between Tourists and Trobriand Islanders

ABSTRACT

When tourists visit cultural tourism destinations, the primary form of interaction between visitors and local residents is in the exchange of money for material objects and performances. While purchase of cultural commodities in tourism contexts may appear to be simple market transactions, they are often in fact morally fraught sites of ambiguous interaction, invested with disparate meanings by different participants. Drawing on Bloch and Parry's (1989 Bloch, Maurice. 1989. The symbolism of money in Imerina. In Money and the Morality of Exchange, edited by J. Parry & M. Bloch. pp. 165–190. Cambridge: Cambridge University Press. [Google Scholar]) analysis of the symbolism of money and its relationship to culturally constructed ideas about production, consumption, circulation, and exchange, this article examines the conflicting and contested views of cash transactions and other types of exchange in meetings between tourists and Trobriand Islanders in Papua New Guinea. I argue that intercultural exchange in tourism is not necessarily a straightforward commodity exchange, but evokes social relations that are often quite differently conceptualized by the producers and consumers of touristic products.     

Adaptation and validation of the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) for the Netherlands

Background

The Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) is the first disease-specific instrument for pulmonary arterial hypertension (PAH) to assess patient-perceived symptoms, activity limitations and quality of life. To be able to use this questionnaire in the Netherlands, the aim of the study was to translate and validate this instrument for the Dutch-speaking population.

Methods

First the CAMPHOR was translated into Dutch (by means of a bilingual and a lay panel) and field-tested by means of cognitive debriefing interviews with ten PAH patients. For psychometric evaluation, 80 patients with PAH or chronic thromboembolic pulmonary hypertension (CTEPH) were asked to complete the CAMPHOR twice over a two-week period. To test for construct validity, participants also completed the Nottingham Health Profile (NHP).

Results

The Dutch version of the CAMPHOR showed high internal consistency for all scales (Cronbach’s alpha 0.89–0.91) and excellent reproducibility over two weeks (reliability coefficients 0.87–0.91). Concurrent validity showed that the CAMPHOR scales correlated as expected with the NHP scales. The CAMPHOR was able to distinguish between patient groups based on self-reported general health status, disease severity and NYHA classification demonstrating evidence of known group validity. The CAMPHOR activity limitations scale correlated moderately with the distance walked during the 6?minute walk test (r = ?0.47, p < 0.01) and the symptoms scale with the Borg dyspnoea score (r = 0.51, p < 0.01).

Conclusion

The Dutch version of the CAMPHOR is a reliable and valid measure of quality of life and health status in patients with PAH and CTEPH is recommended for use in routine care and in clinical research.

     

Sentinel Hospital-Based Surveillance for Assessment of Burden of Rotavirus Gastroenteritis in Children in Pakistan

Objectives

To determine the burden and molecular epidemiology of rotavirus gastroenteritis in children hospitalized with severe acute watery diarrhea in Pakistan prior to introduction of rotavirus vaccine.

Methods

A cross-sectional study was carried out over a period of two years from 2006 – 2008 at five sentinel hospitals in the cities of Karachi, Lahore, Rawalpindi, and Peshawar. Stool samples collected from children under five years of age hospitalized with severe acute watery diarrhea were tested for rotavirus antigen via enzyme immunoassay (EIA) (IDEA REF K6020 Oxoid Ltd (Ely), Cambridge, United Kingdom). A subset of EIA positive stool samples were further processed for genotyping.

Results

6679 children were enrolled and stool specimens of 2039 (30.5%) were positive for rotavirus. Rotavirus positivity ranged from 16.3% to 39.4% in the 5 hospitals with highest positivity in Lahore. 1241 (61%) of all rotavirus cases were in infants under one year of age. Among the strains examined for G-serotypes, the occurrence of G1, G2, G9 and G4 strains was found to be 28%, 24%, 14% and 13%, respectively. Among P-types, the most commonly occurring strains were P6 (31.5%) followed by P8 (20%) and P4 (12%). Prevalent rotavirus genotype in hospitalized children of severe diarrhea were G1P[8] 11.6% (69/593), followed by G2P[4] 10.4% (62/593), and G4P[6] 10.1% (60/593).

Conclusions

Approximately one third of children hospitalized with severe gastroenteritis in urban centers in Pakistan have rotavirus. Introduction of rotavirus vaccine in Pakistan''s national immunization program could prevent many severe episodes and diarrheal deaths.     

The Cambridge History of the Native Peoples of the Americas: Vol. 2: Mesoamerica, Part 1.; The Cambridge History of the Native Peoples of the Americas: Vol. 2: Mesoamerica, Part 2.

The Cambridge History of the Native Peoples of the Americas: Vol. 2: Mesoamerica, Part 1. Richard E. W. Adams and Murdo J. MacLeod. eds. Cambridge: Cambridge University Press, 2000. 571 pp.
The Cambridge History of the Native Peoples of the Americas: Vol. 2: Mesoamerica, Part 2. Richard E. W. Adams and Murdo J. MacLeod. eds. Cambridge: Cambridge University Press, 2000. 455 pp.     

Changes in Tobacco Smoke Exposure following the Institution of a Smoke-Free Policy in the Boston Housing Authority

Introduction

To protect residents from tobacco smoke exposure (TSE), the Boston Housing Authority (BHA) prohibited smoking in BHA-owned apartments beginning in 2012. Our goal was to determine if the smoke-free policy reduced TSE for non-smoking BHA residents.

Methods

We compared TSE before the smoke-free policy (2012) and one year later among BHA residents as well as residents of the neighboring Cambridge Housing Authority (CHA) where no such policy was in place. Participants were a convenience sample of adult non-smoking BHA and CHA residents cohabitating with only non-smokers. Main outcomes were 7-day airborne nicotine in participants’ apartments; residents’ saliva cotinine; and residents’ self-reported TSE.

Results

We enrolled 287 confirmed non-smokers (192 BHA, 95 CHA). Seventy-nine percent (229) were assessed at follow-up. At baseline, apartment and resident TSE were high in both housing authorities (detectable airborne nicotine: 46% BHA, 48% CHA; detectable saliva cotinine: 49% BHA, 70% CHA). At follow-up there were significant but similar declines in nicotine in both sites (detectable: -33% BHA, -39% CHA, p = 0.40). Detectable cotinine rose among BHA residents while declining among CHA participants (+17% BHA vs. -13% CHA, p = 0.002). Resident self-reported TSE within and outside of the housing environment decreased similarly for both BHA and CHA residents.

Conclusions

Apartment air nicotine decreased after the introduction of the smoke-free policy, though the decline may not have resulted from the policy. The BHA policy did not result in reduced individual-level TSE. Unmeasured sources of non-residential TSE may have contributed to BHA residents’ cotinine levels.