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1.  A randomized controlled trial of subantimicrobial-dose doxycycline to prevent unscheduled bleeding with continuous oral contraceptive pill use☆ 
Contraception  2011;85(4):351-358.
Unscheduled bleeding is the main side effect of continuous oral contraceptive pills (OCPs) and has been correlated with the up-regulation of matrix metalloprotineases (MMPs). The study objective was to determine if prophylactic administration of doxycycline (an MMP inhibitor at low subantimicrobial doses) would prevent unscheduled bleeding during the initiation of a continuous OCP.
Study Design
Subjects using cyclic hormonal contraceptives (combined OCPs, patch or ring) without unscheduled bleeding were switched to continuous OCPs (20 mcg ethinyl estradiol/100 mcg levonorgestrel). They were randomized to receive daily doxycycline [sustained-release subantimicrobial dose (40 mg daily)] or placebo for the first 84 days and then observed for an additional 28 days on the continuous OCP alone. The number of bleeding/spotting days and the time in days it took to achieve amenorrhea were compared using a t test.
Sixty-five subjects were randomized. Although the use of doxycycline did not significantly decrease the number of mean bleeding/spotting days in the first 84 days of the study [doxycycline 14.75 (SE 2.30), placebo 17.78 (2.31), p=.36], women who received doxycycline had a significantly earlier onset of amenorrhea [mean last day of bleeding/spotting doxycycline 61.7 (7.7), placebo 85.2 (6.7), p=.03].
The coadministration of subantimicrobial-dose doxycycline during initiation of continuous OCPs results in a significant reduction in the length of time needed to achieve amenorrhea.
PMCID: PMC5045031  PMID: 22067758
Continuous oral contraceptive pills; Matrix metalloproteinases; Bleeding; Contraceptive induced amenorrhea; Doxycycline; Subantimicrobial-dose doxycycline
2.  Uninsured but Eligible Children 
Medical care  2008;46(1):3-8.
Despite expansions in public health insurance programs, millions of US children lack coverage. Nearly two-thirds of Oregon’s uninsured children seem to be eligible for public insurance.
We sought to identify uninsured but eligible children and to examine how parental coverage affects children’s insurance status.
We collected primary data from families enrolled in Oregon’s food stamp program, which has similar eligibility requirements to public health insurance in Oregon. In this cross-sectional, multivariable analysis, results from 2861 surveys were weighted back to a population of 84,087 with nonresponse adjustment. Key predictor variables were parental insurance status and type of insurance; the outcome variable was children’s insurance status.
Nearly 11% of children, presumed eligible for public insurance, were uninsured. Uninsurance among children was associated with being Hispanic, having an employed parent, and higher household earnings (133–185% of the federal poverty level). Children with an uninsured parent were more likely to be uninsured, compared with those who had insured parents (adjusted odds ratio 14.21, 95% confidence interval 9.23–20.34). More surprisingly, there was a higher rate of uninsured children among privately-insured parents, compared with parents covered by public insurance (adjusted odds ratio 4.39, 95% confidence interval 2.00–9.66).
Low-income Oregon parents at the higher end of the public insurance income threshold and those with private insurance were having the most difficulty keeping their children insured. These findings suggest that when parents succeed in pulling themselves out of poverty and gaining employment with private health insurance coverage, children may be getting left behind.
PMCID: PMC4926761  PMID: 18162849
insurance coverage; healthcare access; primary healthcare; Medicaid; children’s healthcare
3.  Growth Hormone Tumor Histological Subtypes Predict Response to Surgical and Medical Therapy 
Endocrine  2014;49(1):231-241.
Growth hormone (GH) pituitary tumors are associated with significant morbidity and mortality. Current treatments, including surgery and medical therapy with somatostatin analogues (SSA), dopamine agonists and/or a GH receptor antagonist, result in disease remission in approximately half of patients. Predictors of GH tumor response to different therapies have been incompletely defined based on histologic subtype, particularly densely (DG) versus sparsely (SG) granulated adenomas. The aim of this study was to examine our own institutional experience with GH adenomas and correlate how subtype related to clinical parameters as well as response to surgery and medical therapies.
A retrospective chart review of 101 acromegalic patients operated by a single neurosurgeon was performed. Clinical data were correlated with histologic subtype and disease control, as defined by IGF-1 levels, and random growth hormone levels in response to surgery and/or medical therapies.
SG tumors, compared to DG, occurred in younger patients (p=0.0010), were 3-fold larger (p=0.0030), but showed no differences in tumor-invasion characteristics (p=0.12). DG tumors had a higher rate of remission in response to surgery compared to SG, 65.7% vs. 14.3% (p<0.0001), as well as to medical therapy with SSAs (68.8% for DG vs. 28.6% for SG tumors; p=0.028). SG tumors not controlled with SSAs consistently responded to a switch to, or addition of, a GH receptor antagonist.
Histological GH tumor subtyping implicates a different clinical phenotype and biologic behavior, and provides prognostic significance for surgical success and response to medical therapies.
PMCID: PMC4331291  PMID: 25129651
Acromegaly; dense GH tumors; sparse GH tumors; somatostatin analogue; pegvisomant
4.  Left Ventricular Dilatation Increases the Risk of Ventricular Arrhythmias in Patients With Reduced Systolic Function 
Reduced left ventricular (LV) ejection fraction increases the risk of ventricular arrhythmias; however, LV ejection fraction has a low sensitivity to predict ventricular arrhythmias. LV dilatation and mass may be useful to further risk-stratify for ventricular arrhythmias.
Methods and Results
Patients from the Genetic Risk of Assessment of Defibrillator Events (GRADE) study (N =930), a study of heart failure subjects with defibrillators, were assessed for appropriate implantable cardioverter-defibrillator shock and death, heart transplant, or ventricular assist device placement by LV diameter and mass. LV mass was divided into normal, mild, moderate, and severe classifications. Severe LV end-diastolic diameter had worse shock-free survival than normal and mild LV end-diastolic diameter (P =0.0002 and 0.0063, respectively; 2-year shock free, severe 74%, moderate 80%, mild 91%, normal 88%; 4-year shock free, severe 62%, moderate 69%, mild 72%, normal 81%) and freedom from death, transplant, or ventricular assist device compared with normal and moderate LV end-diastolic diameter (P<0.0001 and 0.0441, respectively; 2-year survival: severe 78%, moderate 85%, mild 82%, normal 89%; 4-year survival: severe 55%, moderate 64%, mild 63%, normal 74%). Severe LV mass had worse shock-free survival than normal and mild LV mass (P =0.0370 and 0.0280, respectively; 2-year shock free: severe 80%, moderate 81%, mild 91%, normal 87%; 4-year shock free: severe 68%, moderate 73%, mild 76%, normal 76%) but no association with death, transplant, or ventricular assist device (P =0.1319). In a multivariable Cox proportional hazards analysis adjusted for LV ejection fraction, LV end-diastolic diameter was associated with appropriate implantable cardioverter-defibrillator shocks (hazard ratio 1.22, P =0.020). LV end-diastolic diameter was associated with time to death, transplant, or ventricular assist device (hazard ratio 1.29, P =0.0009).
LV dilatation may complement ejection fraction to predict ventricular arrhythmias.
Clinical Trial Registration
URL: Unique identifier: NCT02045043.
PMCID: PMC4599449  PMID: 26231842
heart failure; ventricular arrhythmias
5.  Uninsurance among Children Whose Parents Are Losing Medicaid Coverage: Results from a Statewide Survey of Oregon Families 
Health Services Research  2008;43(1 Pt 2):401-418.
Thousands of adults lost coverage after Oregon's Medicaid program implemented cost containment policies in March 2003. Despite the continuation of comprehensive public health coverage for children, the percentage of uninsured children in the state rose from 10.1 percent in 2002 to 12.3 percent in 2004 (over 110,000 uninsured children). Among the uninsured children, over half of them were likely eligible for public health insurance coverage.
Research Objective
To examine barriers low-income families face when attempting to access children's health insurance. To examine possible links between Medicaid cutbacks in adult coverage and children's loss of coverage.
Data Source/Study Setting
Statewide primary data from low-income households enrolled in Oregon's food stamp program.
Study Design
Cross-sectional analysis. The primary predictor variable was whether or not any adults in the household recently lost Medicaid coverage. The main outcome variables were children's current insurance status and children's insurance coverage gaps.
Data Collection
A mail-return survey instrument was designed to collect information from a stratified, random sample of households with children presumed eligible for publicly funded health insurance programs.
Principal Findings
Over 10 percent of children in the study population eligible for publicly funded health insurance programs were uninsured, and over 25 percent of these children had gaps in insurance coverage during a 12-month period. Low-income children who were most likely to be uninsured or have coverage gaps were Hispanic; were teenagers older than 14; were in families at the higher end of the income threshold; had an employed parent; or had a parent who was uninsured. Fifty percent of the uninsured children lived in a household with at least one adult who had recently lost Medicaid coverage, compared with only 40 percent of insured children (p=.040). Similarly, over 51 percent of children with a recent gap in insurance coverage had an adult in the household who lost Medicaid, compared with only 38 percent of children without coverage gaps (p<.0001). After adjusting for ethnicity, age, household income, and parental employment, children living in a household with an adult who lost Medicaid coverage after recent cutbacks had a higher likelihood of having no current health insurance (OR 1.44, 95 percent CI 1.02, 2.04), and/or having an insurance gap (OR 1.79, 95 percent CI 1.36, 2.36).
Uninsured children and those with recent coverage gaps were more likely to have adults in their household who lost Medicaid coverage after recent cutbacks. Although current fiscal constraints prevent many states from expanding public health insurance coverage to more parents, states need to be aware of the impact on children when adults lose coverage. It is critical to develop strategies to keep parents informed regarding continued eligibility and benefits for their children and to reduce administrative barriers to children's enrollment and retention in public health insurance programs.
PMCID: PMC2323132  PMID: 18199193
Insurance coverage; health care access; primary health care; Medicaid; children's health care
6.  Diurnal patterns of salivary cortisol and DHEA using a novel collection device: Electronic monitoring confirms accurate recording of collection time using this device 
Psychoneuroendocrinology  2013;38(9):1596-1606.
The accurate indication of saliva collection time is important for defining the diurnal decline in salivary cortisol as well as characterizing the cortisol awakening response.. We tested a convenient and novel collection device for collecting saliva on strips of filter paper in a specially constructed booklet for determination of both cortisol and DHEA. In the present study, 31 healthy adults (mean age 43.5 yrs.) collected saliva samples four times a day on three consecutive days using filter paper collection devices (Saliva Procurement and Integrated Testing (SPIT) booklet) which were maintained during the collection period in a large plastic bottle with an electronic monitoring cap. Subjects were asked to collect saliva samples at awakening, 30 min. after awakening, before lunch and 600 min. after awakening. The time of awakening and the time of collection before lunch were allowed to vary by each subjects’ schedule. A reliable relationship was observed between the time recorded by the subject directly on the booklet and the time recorded by electronic collection device (n = 286 observations; r2 = 0.98). However, subjects did not consistently collect the saliva samples at the two specific times requested, 30 and 600 min. after awakening. Both cortisol and DHEA revealed diurnal declines.. In spite of variance in collection times at 30 min. and 600 min. after awakening, the slope of the diurnal decline in both salivary cortisol and DHEA were similar when we compared collection tolerances of ± 7.5 and ± 15 min. for each steroid.. These unique collection booklets proved to be a reliable method for recording collection times by subjects as well as for estimating diurnal salivary cortisol and DHEA patterns.
PMCID: PMC3755093  PMID: 23490073
Adherence; Cortisol; DHEA; compliance; cortisol awakening response; diurnal rhythm; steroids; saliva; stress; hypothalamic pituitary adrenal axis
7.  Effect of Low Concentrations of Apomorphine on Parkinsonism in a Randomized, Placebo-Controlled, Crossover Study 
Archives of Neurology  2008;65(2):193-198.
To determine whether low concentrations of a dopamine agonist worsen parkinsonism, which would suggest that activation of presynaptic dopamine autoreceptors causes a super-off state.
Randomized, double-blind, placebo-controlled, crossover clinical trial.
Academic movement disorders center.
Patients with Parkinson disease and motor fluctuations.
Fourteen patients with Parkinson disease and motor fluctuations were randomized to receive 1 of 6 possible sequences of placebo, low-dose (sub-threshold) apomorphine hydrochloride, and high-dose (threshold to suprathreshold) apomorphine hydrochloride infusions. Subthreshold doses of apomorphine hydrochloride (12.5 μg/kg/h every 2 hours and 25 μg/kg/h every 2 hours), threshold to suprathreshold doses of apomorphine hydrochloride (50 μg/kg/h every 2 hours and 100 μg/kg/h every 2 hours), and placebo were infused for 4 hours daily for 3 consecutive days.
Main Outcome Measures
Finger and foot tapping rates.
There was no decline in finger or foot tapping rates during the low-dose apomorphine hydrochloride infusions relative to placebo. The high-dose infusions increased foot tapping (P<.001) and trended toward increasing finger tapping compared with placebo infusions.
Subthreshold concentrations of apomorphine did not worsen parkinsonism, suggesting that pre-synaptic dopamine autoreceptors are not important to the motor response in moderate to advanced Parkinson disease.
PMCID: PMC3390309  PMID: 18268187
8.  Reexamination of Testosterone, Dihydrotestosterone, Estradiol and Estrone Levels across the Menstrual Cycle and in Postmenopausal Women Measured by Liquid Chromatography Tandem Mass Spectrometry 
Steroids  2010;76(1-2):177-182.
Measuring serum androgen levels in women has been challenging due to limitations in method accuracy, precision sensitivity and specificity at low hormone levels. The clinical significance of changes in sex steroids across the menstrual cycle and lifespan has remained controversial, in part due to these limitations. We used validated liquid chromatography tandem mass spectrometry(LC-MS/MS) assays to determine testosterone (T) and dihydrotestosterone (DHT) along with estradiol (E2) and estrone (E1) levels across the menstrual cycle of 31 healthy premenopausal females and in 19 postmenopausal females. Samples were obtained in ovulatory women in the early follicular phase (EFP), midcycle and mid luteal phase (MLP).
Overall, the levels of T, DHT, E2 and E1 in premenopausal women measured by LCMS/MS were lower overall than previously reported with immunoassays. In premenopausal women, serum T, Free T, E2, E1 and SHBG levels peaked at midcycle and remained higher in the MLP, whereas DHT did not change. In postmenopausal women, T, free T, SHBG and DHT were significantly lower than in premenopausal women, concomitant with declines in E2 and E1. These data support the hypothesis that the changes in T and DHT that occur across the cycle may reflect changes in SHBG and estrogen, whereas in menopause, androgen levels decrease. LC-MS/MS may provide more accurate and precise measurement of sex steroid hormones than prior immunoassay methods and can be useful to assess the clinical significance of changes in T, DHT, E2 and E1 levels in females.
PMCID: PMC3005029  PMID: 21070796
sex hormones; liquid chromatography mass spectrometry; menopause; menstrual cycle; testosterone; estradiol
9.  Physical Activity and the Risk of Dementia in Oldest Old 
Journal of aging and health  2007;19(2):242-259.
This study evaluated the protective role of physical activity (PA) against cognitive impairment (CI) in the oldest old (age ≥ 85).
Prospective data on 66 optimally healthy, oldest old adults (mean age 88.5) were analyzed using survival analysis.
In all, 12 men and 11 women reported exercising > 4 hours per week, and 38 participants developed CI (mean onset age 93; mean follow-up 4.7 years). The effect of exercise was modified by gender. In more active women (> 4 hours/week), the risk of CI was reduced by 88% (95% confidence interval 0.03, 0.41) compared to those less active. Less active women had 2 times the incidence rate of CI compared to less active men and almost 5 times the rate compared to active women.
This study demonstrates the beneficial effects of exercise on healthy brain aging even in the oldest old and emphasizes the importance of increasing PA in older women.
PMCID: PMC3110722  PMID: 17413134
oldest old; physical activity; exercise; dementia; cognitive impairment
10.  Using Built Environmental Observation Tools: Comparing Two Methods of Creating a Measure of the Built Environment 
Identify an efficient method of creating a comprehensive and concise measure of the built environment integrating data from geographic information systems (GIS) and the Senior Walking Environmental Assessment Tool (SWEAT).
Cross-sectional study using a population sample.
Eight municipally defined neighborhoods in Portland, Oregon.
Adult residents (N = 120) of audited segments (N = 363).
We described built environmental features using SWEAT audits and GIS data. We obtained information on walking behaviors and potential confounders through in-person interviews.
We created two sets of environviental measures, one based on the conceptual framework used to develop SWEAT and another using principal component analysis (PCA). Each measure’s association with walking for transportation and exercise was then assessed and compared using logistic regression.
A priori measures (destinations, safety, aesthetics, and functionality) and PCA measures (accessibility, comfort/safety, maintenance, and pleasantness) were analogous in conceptual meaning and had similar associations with walking. Walking for transportation was associated with destination accessibility and functional elements, whereas walking for exercise was associated with maintenance of the walking area and protection from traffic. However, only PCA measures consistently reached statistical significance.
The measures created with PCA were more parsimonious than those created a priori. Performing PCA is an efficient method of combining and scoring SWEAT and GIS data.
PMCID: PMC3105357  PMID: 20465151
Environment; Residence Characteristics; Walking; Principal Component Analysis; Research Design; Prevention Research
11.  Correlations Between Endoscopy Score and Quality-of-Life Changes After Sinus Surgery 
To assess whether change in endoscopy score correlates with change in health-related quality of life (HRQOL) following endoscopic sinus surgery (ESS) for chronic rhinosinusitis (CRS).
Tertiary rhinology clinic
One hundred two adult patients, with and without nasal polyposis, who elected to undergo ESS and were followed for 12 ± 2 months postoperatively.
Patient characteristics and Lund-Mackay computed tomography scores were recorded preoperatively. Lund-Kennedy endoscopy scores and 2 HRQoL surveys, the Rhinosinusitis Disability Index (RSDI) and Chronic Sinusitis Survey (CSS), were examined before and after surgery.
Main Outcome Measures
Postoperative changes in endoscopy score and HRQOL were examined using bivariate and multivariate analyses.
Statistically significant improvements were found in endoscopy score (p<0.001) and for all total and subscale HRQoL measures (p<0.001). After controlling for baseline status and comorbid factors, improvement in endoscopy score significantly correlated with 12 month improvement on the total RSDI (p=0.01), the physical (p=0.01) and functional (p=0.02) subscales of the RSDI, and the symptom subscale of the CSS (p=0.003), but could explain only 25.5–36.6% of the linear variation for these HRQOL improvements.
For most patients, endoscopy scores and disease specific HRQOL significantly improved after endoscopic sinus surgery. Changes in endoscopy scores explain a portion of the improvement in HRQOL. For patients with CRS, improvements in disease specific HRQoL outcomes are complex, multidimensional constructs that cannot be entirely explained by surgical changes measured by endoscopic examination.
PMCID: PMC2860109  PMID: 20403849
Endoscopic sinus surgery; endoscopy; outcomes; quality-of-life; chronic sinusitis
12.  Age differences in perception and awareness of emotion 
Neurobiology of aging  2007;30(8):1305-1313.
We investigated the effects of age and gender on emotional perception and physiology using electrodermal skin conductance response (SCR) and examined whether SCR related to subjective perceptions of emotional pictures. Older adults found pictures to be more positive and arousing than younger participants. Older women rated pictures more extremely at both ends of the valence continuum: they rated positive pictures more positively and negative pictures more negatively. Elders were less likely to show measurable SCRs. However, magnitude of SCRs when a response occurred did not differ between young and old. Subjective ratings of emotion correlated with physiological responses in younger participants, but they were unrelated in older participants. Thus, in older adults the perception of emotional events was disconnected from the physiological state induced by emotion.
PMCID: PMC2733236  PMID: 18155323
13.  Impact of obesity on oral contraceptive pharmacokinetics and hypothalamic-pituitary-ovarian activity 
Contraception  2009;80(2):119-127.
This study was conducted to determine whether increased body mass index (BMI) affects oral contraceptive (OC) pharmacokinetics and suppression of hypothalamic-pituitary-ovarian (HPO) axis activity.
Study design
Ovulatory reproductive-age women of normal (< 25 kg/m2; n = 10) and obese (> 30 kg/m2; n = 10) BMI received OCs for two cycles (prospective cohort). Subjects were admitted for two 48-h inpatient stays at the beginning and end of the hormone-free interval. Ethinyl estradiol (EE) and levonorgestrel (LNG) levels were evaluated during both inpatient stays. Gonadotropin pulsatility (FSH and LH) was measured during the second inpatient stay. Estradiol (E2) and progesterone (P) were measured daily during inpatient stays and twice per week in Cycle 2.
BMI was greater in the obese, compared to the normal BMI group [37.3 kg/m2 (SD 6.0) versus 21.9 kg/m2 (SD 1.6); p < 0.05]. The LNG half-life was significantly longer in the obese group (52.1 ± 29.4 h versus 25.6 ± 9.3 h, p < 0.05) which correlated with a lower maximum LNG concentration on Cycle 2, Day 1 [1.9 ng/mL (SD 0.5) versus 2.5 ng/mL (SD 0.7)] and a longer time to reach steady-state (10 versus 5 days), in obese women. There were no significant differences in volume of distribution between groups. LH pulse parameters did not differ statistically between groups but trended towards greater HPO activity in the obese group. Additionally, more obese (6/10 versus 3/10 normal BMI, p > 0.05) women exhibited E2 levels consistent with development of a dominant follicle, and P levels consistent with ovulation (2/10 versus 1/10) during Cycle 2.
Compared to women of normal BMI, obese women exhibit differences in OC pharmacokinetics that are associated with greater HPO activity.
PMCID: PMC2736633  PMID: 19631786
14.  A Bayesian approach to modeling associations between pulsatile hormones 
Biometrics  2009;65(2):650-659.
Many hormones are secreted in pulses. The pulsatile relationship between hormones regulates many biological processes. To understand endocrine system regulation, time series of hormone concentrations are collected. The goal is to characterize pulsatile patterns and associations between hormones. Currently each hormone on each subject is fitted univariately. This leads to estimates of the number of pulses and estimates of the amount of hormone secreted; however, when the signal-to-noise ratio is small, pulse detection and parameter estimation remains difficult with existing approaches. In this paper, we present a bivariate deconvolution model of pulsatile hormone data focusing on incorporating pulsatile associations. Through simulation, we exhibit that using the underlying pulsatile association between two hormones improves the estimation of the number of pulses and the other parameters defining each hormone. We develop the one-to-one, driver-response case and show how birth-death MCMC can be used for estimation. We exhibit these features through a simulation study and on the relationship between luteinizing and follicle stimulating hormones.
PMCID: PMC2845528  PMID: 18759850
15.  Influence of stressors on breast cancer incidence in the Women’s Health Initiative 
To examine associations among life events stress, social support, and breast cancer incidence in a cohort of postmenopausal women.
Design and main outcome measure
Women’s Health Initiative observational study participants, breast cancer free at entry, who provided assessment of stressful life events, social support, and breast cancer risk factors, were prospectively followed for breast cancer incidence (n=84,334).
During an average of 7.6 years of follow-up, 2,481 invasive breast cancers were diagnosed. In age-adjusted proportional hazards models, one stressful life event was associated with increased risk, but risk decreased with each additional stressful life event. After adjustment for confounders the decreasing risk was not significant. Stressful life events and social support appeared to interact in relation to breast cancer risk such that women who had greater number of stressful life events and low social support had a decreased risk of breast cancer.
This study found no independent association between stressful life events and breast cancer risk. The results are compatible with a more complex model of psychosocial factors interacting in relation to breast cancer risk.
PMCID: PMC2657917  PMID: 19290705
16.  The Relation between Neighborhood Built Environment and Walking Activity among Older Adults 
American Journal of Epidemiology  2008;168(4):461-468.
The association of neighborhood built environment with walking activity has received growing attention, although most studies have relied upon subjective measures of the built environment and few have examined the relation between built environment and walking among older adults. This 2001 study examined the relation between objectively measured characteristics of the local neighborhood and walking activity among a sample of 546 community-dwelling older adults in Portland, Oregon. A geographic information system was used to derive measures of the built environment within a quarter-mile (0.4 km) and half-mile (0.8 km) radius around each participant's residence. Multilevel regression analysis was used to examine the association of built environment with walking behavior. No association between built environment and the likelihood of walking or not walking was observed in this cohort of older adults. However, among those participants who reported some degree of walking activity, average time spent walking per week was significantly associated with amount of automobile traffic and number of commercial establishments in their local neighborhood. These findings suggest that built environment may not play a significant role in whether older adults walk, but, among those who do walk, it is associated with increased levels of activity.
PMCID: PMC2727277  PMID: 18567638
aged; environment design; geographic information systems; health behavior; regression analysis; residence characteristics; urban health; walking
17.  Analysis of Individual Social-ecological Mediators and Moderators and Their Ability to Explain Effect of a Randomized Neighborhood Walking Intervention 
Using data from the SHAPE trial, a randomized 6-month neighborhood-based intervention designed to increase walking activity among older adults, this study identified and analyzed social-ecological factors mediating and moderating changes in walking activity.
Three potential mediators (social cohesion, walking efficacy, and perception of neighborhood problems) and minutes of brisk walking were assessed at baseline, 3-months, and 6-months. One moderator, neighborhood walkability, was assessed using an administrative GIS database. The mediating effect of change in process variables on change in brisk walking was tested using a product-of-coefficients test, and we evaluated the moderating effect of neighborhood walkability on change in brisk walking by testing the significance of the interaction between walkability and intervention status.
Only one of the hypothesized mediators, walking efficacy, explained the intervention effect (product of the coefficients (95% CI) = 8.72 (2.53, 15.56). Contrary to hypotheses, perceived neighborhood problems appeared to suppress the intervention effects (product of the coefficients (95% CI = -2.48, -5.6, -0.22). Neighborhood walkability did not moderate the intervention effect.
Walking efficacy may be an important mediator of lay-lead walking interventions for sedentary older adults. Social-ecologic theory-based analyses can support clinical interventions to elucidate the mediators and moderators responsible for producing intervention effects.
PMCID: PMC2728705  PMID: 19643024
18.  Traditional smallpox vaccination with reduced risk of inadvertent contact spread by administration of povidone iodine ointment 
Vaccine  2007;26(3):430-439.
One concern with traditional smallpox vaccination is inadvertent spread of virus to atopic or immunocompromised contacts. To reduce this risk, we tested the ability of povidone iodine to inactivate infectious virus at the vaccination site beginning at 7 days after transcutaneous smallpox vaccination. This ointment rapidly inactivated virus on the skin without reducing neutralizing antibody titers or antiviral T cell responses. Moreover, there was no delay in healing/eschar separation following povidone iodine application. Together, this indicates that administration of an antiviral/antimicrobial cream can effectively block virus shedding after traditional smallpox vaccination and reduce the risks of autoinoculation or contact spread.
PMCID: PMC2323604  PMID: 18083278
Smallpox vaccination; Vaccinia; Povidone iodine ointment

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