Centrally Acting ACE Inhibitor Use and Physical Performance in Older Adults

BACKGROUND

There is conflicting evidence regarding the role of angiotensin-converting enzyme inhibitors and physical function. While some studies show improvements in muscle strength and physical function, others show no significant difference or decreased performance. This ambiguity could be due to differential effects of angiotensin-converting enzyme inhibitor subtypes which can be categorized as centrally or peripherally-acting based upon their ability to cross the blood-brain barrier.

OBJECTIVE

The objective of this study is to compare physical performance measures among angiotensin-converting enzyme inhibitor subtype users.

METHODS

Design: Cross-sectional Setting: Ambulatory Participants: Performed in 364 participants in the Health and Retirement Study cohort who were ≥ 65 years (median age (IQR) 74.00 (69-80) years.

MEASUREMENTS

Average difference in hand grip (kg), gait speed(m/s) and peak expiratory flow (L/min).

RESULTS

Compared to participants on a peripherally-acting angiotensin-converting enzyme inhibitor (113 (31%)), those on a centrally-acting agent (251(69%)) had stronger grip strength 28.9 ±1.0 vs 26.3±1.0, p=.011 and higher peak expiratory flow rates 316.8±130.4 vs. 280.0±118.5, p= .011 in unadjusted analysis. After multiple adjustments the difference in PEF remained statistically significant (Estimate(CI) 26.5, 95% CI 2.24, 50.5, p = 0.032).

CONCLUSION

Our results suggest that in older adults the use of centrally-acting angiotensin-converting enzyme inhibitors compared to a peripherally acting angiotensin-converting enzyme inhibitors was associated with better lung function in older individuals.

World Trade Center exposure, post-traumatic stress disorder, and subjective cognitive concerns in a cohort of rescue/recovery workers

OBJECTIVE

To determine whether World Trade Center (WTC)-exposure intensity and post-traumatic stress disorder (PTSD) are associated with subjective cognitive change in rescue/recovery workers.

METHOD

The population included 7875 rescue/recovery workers who completed a subjective cognition measure, the Cognitive Function Instrument (CFI), between 3/1/2018 and 2/28/2019 during routine monitoring, indicating whether they had experienced cognitive and functional difficulties in the past year. Higher scores indicated greater self-perceived cognitive change. Probable PTSD, depression, and alcohol abuse were evaluated by validated mental health screeners. Logistic regression assessed the associations of WTC exposure and current PTSD with top-quartile (≥2) CFI score, and of early post-9/11 PTSD with top-quartile CFI in a subpopulation (N = 6440). Models included demographics, smoking, depression, and alcohol abuse as covariates.

RESULTS

Mean age at CFI completion was 56.7 ± 7.7 (range: 36-81). Participants with high-intensity WTC exposure had an increased likelihood of top-quartile CFI score (odds ratio[OR] vs. low exposure: 1.32, 95%CI: 1.07-1.64), controlling for covariates. Current and early PTSD were both associated with top-quartile CFI (OR: 3.25, 95%CI: 2.53-4.19 and OR: 1.56, 95%CI: 1.26-1.93) respectively.

CONCLUSIONS

High-intensity WTC exposure was associated with self-reported cognitive change 17 years later in rescue/recovery workers, as was PTSD. Highly WTC-exposed subgroups may benefit from additional cognitive evaluation and monitoring of cognition over time.

A longitudinal linear model of patient characteristics to predict failure to attend an inner-city chronic pain clinic

Patients often fail to attend appointments in chronic pain clinics for unknown reasons. We hypothesized that certain patient characteristics predict failure to attend scheduled appointments, pointing to systematic barriers to accessing chronic pain services for certain underserved populations. We collected retrospective data from a longitudinal observational cohort of patients at an academic pain clinic in Newark, New Jersey. To examine the effect of demographic factors on appointment status, we fit a marginal logistic regression using generalized estimating equations with exchangeable correlation. A total of 1,394 patients with 3,488 total encounters between January 1, 2006, and December 31, 2009, were included. Spanish spoken as a primary language (alternatively Hispanic or other race) and living between 5 and 10 miles from the clinic were associated with reduced odds of arriving for an appointment; making an appointment for a particular complaint such as cancer pain or back pain, an interventional pain procedure scheduled in connection with the appointment, unemployed status, and continuity of care (as measured by office visit number) were associated with increased odds of arriving. Spanish spoken as a primary language and distance to the pain clinic predicted failure to attend a scheduled appointment in our cohort. If these constitute systematic barriers to access, they may be amenable to targeted interventions.

PERSPECTIVE

We identified certain patient characteristics, specifically Spanish spoken as a primary language and geographic distance from the clinic, that predict failure to attend an inner-city chronic pain clinic. These identified barriers to accessing chronic pain services may be modifiable by simple cost-effective interventions.

Respiratory syncytial virus-associated hospitalizations among children less than 24 months of age

BACKGROUND

Respiratory syncytial virus (RSV) infection is a leading cause of hospitalization among infants. However, estimates of the RSV hospitalization burden have varied, and precision has been limited by the use of age strata grouped in blocks of 6 to ≥ 12 months.

METHODS

We analyzed data from a 5-year, prospective, population-based surveillance for young children who were hospitalized with laboratory-confirmed (reverse-transcriptase polymerase chain reaction) RSV acute respiratory illness (ARI) during October through March 2000-2005. The total population at risk was stratified by month of age by birth certificate information to yield hospitalization rates.

RESULTS

There were 559 (26%) RSV-infected children among the 2149 enrolled children hospitalized with ARI (85% of all eligible children with ARI). The average RSV hospitalization rate was 5.2 per 1000 children <24 months old. The highest age-specific rate was in infants 1 month old (25.9 per 1000 children). Infants ≤ 2 months of age, who comprised 44% of RSV-hospitalized children, had a hospitalization rate of 17.9 per 1000 children. Most children (79%) were previously healthy. Very preterm infants (<30 weeks' gestation) accounted for only 3% of RSV cases but had RSV hospitalization rates 3 times that of term infants.

CONCLUSIONS

Young infants, especially those who were 1 month old, were at greatest risk of RSV hospitalization. Four-fifths of RSV-hospitalized infants were previously healthy. To substantially reduce the burden of RSV hospitalizations, effective general preventive strategies will be required for all young infants, not just those with risk factors.

The burgeoning burden of respiratory syncytial virus among children

Respiratory syncytial virus (RSV) was first isolated from infants by Chanock and colleagues in 1957. However, control of this ubiquitous agent has yet to be achieved. RSV is recognized as the primary cause of hospitalization for acute lower respiratory tract illness (LRTI) among infants worldwide. Among children < 5 years old, annual hospitalization rates in the United States (US) is 3/1000 children, and rates in Canada and European countries are similar. In the US the hospitalization rate is 3 times higher than that from influenza or parainfluenza viral infections. Much less appreciated is the clinical and economic burden from RSV outpatients, as few have specific diagnostic testing. Nevertheless, RSV in the US is estimated to cause 1 of 334 hospitalizations, 1 of 38 emergency department visits, but 1 of 13 private practice visits. These outpatient children tend to have moderate to severe illness with approximately three-fourths manifesting labored respirations. RSV burden among outpatients, therefore, is considerable both in size and severity. The global burden of RSV infection is unknown as few studies are from developing countries. Estimates indicate about one-fourth of all acute LRTI occur among children < 5 years, and the greatest burden is among children in developing countries. Currently the only approved means of RSV prophylaxis is passive immunization with humanized F protein monoclonal antibody. Such prophylaxis, however, has limited availability, is expensive, and is recommended only for infants most at risk for severe RSV disease. Only widespread immunization of children is likely to diminish the current burden of RSV infection.

Effectiveness of seasonal influenza vaccines in the United States during a season with circulation of all three vaccine strains

BACKGROUND

Influenza vaccines may be reformulated annually because of antigenic drift in influenza viruses. However, the relationship between antigenic characteristics of circulating viruses and vaccine effectiveness (VE) is not well understood. We conducted an assessment of the effectiveness of US influenza vaccines during the 2010-2011 season.

METHODS

We performed a case-control study comparing vaccination histories between subjects with acute respiratory illness with positive real-time reverse transcription polymerase chain reaction for influenza and influenza test-negative controls. Subjects with acute respiratory illness of ≤7 days duration were enrolled in hospitals, emergency departments, or outpatient clinics in communities in 4 states. History of immunization with the 2010-2011 vaccine was ascertained from vaccine registries or medical records. Vaccine effectiveness was estimated in logistic regression models adjusted for study community, age, race, insurance status, enrollment site, and presence of a high-risk medical condition.

RESULTS

A total of 1040 influenza-positive cases and 3717 influenza-negative controls were included from the influenza season, including 373 cases of influenza A(H1N1), 334 cases of influenza A(H3N2), and 333 cases of influenza B. Overall adjusted VE was 60% (95% confidence interval [CI], 53%-66%). Age-specific VE estimates ranged from 69% (95% CI, 56%-77%) in children aged 6 months-8 years to 38% (95% CI, -16% to 67%) in adults aged ≥65 years.

CONCLUSIONS

The US 2010-2011 influenza vaccines were moderately effective in preventing medically attended influenza during a season when all 3 vaccine strains were antigenically similar to circulating viruses. Continued monitoring of influenza vaccines in all age groups is important, particularly as new vaccines are introduced.

Residential crowding and severe respiratory syncytial virus disease among infants and young children: a systematic literature review

Background

The objective of this literature review was to determine whether crowding in the home is associated with an increased risk of severe respiratory syncytial virus (RSV) disease in children younger than 5 years.

Methods

A computerized literature search of PubMed and EMBASE was conducted on residential crowding as a risk factor for laboratory-confirmed RSV illness in children younger than 5 years. Study populations were stratified by high-risk populations, defined by prematurity, chronic lung disease of prematurity, hemodynamically significant congenital heart disease, or specific at-risk ethnicity (i.e. Alaska Native, Inuit), and mixed-risk populations, including general populations of mostly healthy children. The search was conducted for articles published from January 1, 1985, to October 8, 2009, and was limited to studies reported in English. To avoid indexing bias in the computerized databases, the search included terms for multivariate analysis and risk factors to identify studies in which residential crowding was evaluated but was not significant. Methodological quality of included studies was assessed using a Cochrane risk of bias tool.

Results

The search identified 20 relevant studies that were conducted in geographically diverse locations. Among studies of patients in high-risk populations, 7 of 9 found a statistically significant association with a crowding variable; in studies in mixed-risk populations, 9 of 11 found a significant association with a crowding variable. In studies of high-risk children, residential crowding significantly increased the odds of laboratory-confirmed RSV hospitalization (i.e. odds ratio ranged from 1.45 to 2.85). In studies of mixed-risk populations, the adjusted odds ratios ranged from 1.23 to 9.1. The findings on the effect of residential crowding on outpatient RSV lower respiratory tract infection were inconsistent.

Conclusions

Residential crowding was associated with an increased risk of laboratory-confirmed RSV hospitalization among high-risk infants and young children. This association was consistent despite differences in definitions of residential crowding, populations, or geographic locations.

Effectiveness of non-adjuvanted pandemic influenza A vaccines for preventing pandemic influenza acute respiratory illness visits in 4 U.S. communities

We estimated the effectiveness of four monovalent pandemic influenza A (H1N1) vaccines (three unadjuvanted inactivated, one live attenuated) available in the U.S. during the pandemic. Patients with acute respiratory illness presenting to inpatient and outpatient facilities affiliated with four collaborating institutions were prospectively recruited, consented, and tested for influenza. Analyses were restricted to October 2009 through April 2010, when pandemic vaccine was available. Patients testing positive for pandemic influenza by real-time RT-PCR were cases; those testing negative were controls. Vaccine effectiveness was estimated in logistic regression models adjusted for study community, patient age, timing of illness, insurance status, enrollment site, and presence of high-risk medical conditions. Pandemic virus was detected in 1,011 (15%) of 6,757 enrolled patients. Fifteen (1%) of 1,011 influenza positive cases and 1,042 (18%) of 5,746 test-negative controls had record-verified pandemic vaccination >14 days prior to illness onset. Adjusted effectiveness (95% confidence interval) for pandemic vaccines combined was 56% (23%, 75%). Adjusted effectiveness for inactivated vaccines alone (79% of total) was 62% (25%, 81%) overall and 32% (-92%, 76%), 89% (15%, 99%), and -6% (-231%, 66%) in those aged 0.5 to 9, 10 to 49, and 50+ years, respectively. Effectiveness for the live attenuated vaccine in those aged 2 to 49 years was only demonstrated if vaccination >7 rather than >14 days prior to illness onset was considered (61%∶ 12%, 82%). Inactivated non-adjuvanted pandemic vaccines offered significant protection against confirmed pandemic influenza-associated medical care visits in young adults.

Transplacental congenital human herpesvirus 6 infection caused by maternal chromosomally integrated virus

Congenital human herpesvirus 6 (HHV-6) infection results from germline passage of chromosomally integrated HHV-6 (CI-HHV-6) and from transplacental passage of maternal HHV-6 infection. We aimed to determine whether CI-HHV-6 could replicate and cause transplacentally acquired HHV-6 infection. HHV-6 DNA, variant type, and viral loads were determined with samples (cord blood, peripheral blood, saliva, urine, and hair) obtained from 6 infants with transplacentally acquired HHV-6 and with samples of their parents' hair. No fathers but all mothers of infants with transplacentally acquired HHV-6 had CI-HHV-6, and the mother's CI-HHV-6 variant was the same variant causing the transplacentally acquired congenital HHV-6 infection. This suggests the possibility that CI-HHV-6 replicates and may cause most, if not all, congenital HHV-6 infections.

Diagnostic assays for active infection with human herpesvirus 6 (HHV-6)

BACKGROUND

Human herpesvirus 6 (HHV-6) causes ubiquitous infection in early childhood with lifelong latency or persistence. Reactivation of HHV-6 has been associated with multiple diseases including encephalitis. Chromosomal integration of HHV-6 also occurs. Previous studies have suggested that the detection of HHV-6 DNA in plasma is an accurate marker of active viral replication.

OBJECTIVE

We sought to determine whether PCR assays on plasma could correctly differentiate between primary HHV-6 infection, chromosomal integration of HHV-6 and latent HHV-6 infection.

STUDY DESIGN

We performed qualitative PCR, real-time quantitative PCR (RQ-PCR), and reverse-transcriptase PCR (RT-PCR) assays on samples of peripheral and cord blood mononuclear cells, as well as plasma, from groups of subjects with well defined HHV-6 infection, including subjects with chromosomally integrated HHV-6.

RESULTS AND CONCLUSIONS

The detection of HHV-6 DNA in plasma was 92% sensitive compared to viral isolation for the identification of primary infection with HHV-6. All plasma samples from infants with chromosomally integrated HHV-6 had HHV-6 DNA detectable in plasma while only 5.6% were positive by RT-PCR. The specificity of plasma PCR for active replication of HHV-6 was 84% compared to viral culture while the specificity of RT-PCR was 98%. Our results demonstrate that qualitative or quantitative PCR of plasma is insufficient to distinguish between active viral replication and chromosomal integration with HHV-6. We found a higher specificity of RT-PCR performed on PBMC samples compared to PCR or RQ-PCR performed on plasma when evaluating samples for active HHV-6 replication.

Bronchiolitis: recent evidence on diagnosis and management

Viral bronchiolitis is a leading cause of acute illness and hospitalization of young children. Research into the variation in treatment and outcomes for bronchiolitis across different settings has led to evidence-based clinical practice guidelines. Ongoing investigation continues to expand this body of evidence. Authors of recent surveillance studies have defined the presence of coinfections with multiple viruses in some cases of bronchiolitis. Underlying comorbidities and young age remain the most important predictors for severe bronchiolitis. Pulse oximetry plays an important role in driving use of health care resources. Evidence-based reviews have suggested a limited role for diagnostic laboratory or radiographic tests in typical cases of bronchiolitis. Several large, recent trials have revealed a lack of efficacy for routine use of either bronchodilators or corticosteroids for treatment of bronchiolitis. Preliminary evidence suggests a potential future role for a combination of these therapies and other novel treatments such as nebulized hypertonic saline.

Cognitive activities delay onset of memory decline in persons who develop dementia

BACKGROUND

Persons destined to develop dementia experience an accelerated rate of decline in cognitive ability, particularly in memory. Early life education and participation in cognitively stimulating leisure activities later in life are 2 factors thought to reflect cognitive reserve, which may delay the onset of the memory decline in the preclinical stages of dementia.

METHODS

We followed 488 initially cognitively intact community residing individuals with epidemiologic, clinical, and cognitive assessments every 12 to 18 months in the Bronx Aging Study. We assessed the influence of self-reported participation in cognitively stimulating leisure activities on the onset of accelerated memory decline as measured by the Buschke Selective Reminding Test in 101 individuals who developed incident dementia using a change point model.

RESULTS

Each additional self-reported day of cognitive activity at baseline delayed the onset of accelerated memory decline by 0.18 years. Higher baseline levels of cognitive activity were associated with more rapid memory decline after that onset. Inclusion of education did not significantly add to the fit of the model beyond the effect of cognitive activities.

CONCLUSIONS

Our findings show that late life cognitive activities influence cognitive reserve independently of education. The effect of early life education on cognitive reserve may be mediated by cognitive activity later in life. Alternatively, early life education may be a determinant of cognitive reserve, and individuals with more education may choose to participate in cognitive activities without influencing reserve. Future studies should examine the efficacy of increasing participation in cognitive activities to prevent or delay dementia.

The burden of respiratory syncytial virus infection in young children

BACKGROUND

The primary role of respiratory syncytial virus (RSV) in causing infant hospitalizations is well recognized, but the total burden of RSV infection among young children remains poorly defined.

METHODS

We conducted prospective, population-based surveillance of acute respiratory infections among children under 5 years of age in three U.S. counties. We enrolled hospitalized children from 2000 through 2004 and children presenting as outpatients in emergency departments and pediatric offices from 2002 through 2004. RSV was detected by culture and reverse-transcriptase polymerase chain reaction. Clinical information was obtained from parents and medical records. We calculated population-based rates of hospitalization associated with RSV infection and estimated the rates of RSV-associated outpatient visits.

RESULTS

Among 5067 children enrolled in the study, 919 (18%) had RSV infections. Overall, RSV was associated with 20% of hospitalizations, 18% of emergency department visits, and 15% of office visits for acute respiratory infections from November through April. Average annual hospitalization rates were 17 per 1000 children under 6 months of age and 3 per 1000 children under 5 years of age. Most of the children had no coexisting illnesses. Only prematurity and a young age were independent risk factors for hospitalization. Estimated rates of RSV-associated office visits among children under 5 years of age were three times those in emergency departments. Outpatients had moderately severe RSV-associated illness, but few of the illnesses (3%) were diagnosed as being caused by RSV.

CONCLUSIONS

RSV infection is associated with substantial morbidity in U.S. children in both inpatient and outpatient settings. Most children with RSV infection were previously healthy, suggesting that control strategies targeting only high-risk children will have a limited effect on the total disease burden of RSV infection.

Chromosomal integration of human herpesvirus 6 is the major mode of congenital human herpesvirus 6 infection

OBJECTIVE

We examined the frequency and characteristics of chromosomally integrated human herpesvirus 6 among congenitally infected children.

METHODS

Infants with and without congenital human herpesvirus 6 infection were prospectively monitored. Cord blood mononuclear cell, peripheral blood mononuclear cell, saliva, urine, and hair follicle samples were examined for human herpesvirus 6 DNA. Human herpesvirus 6 RNA, serum antibody, and chromosomally integrated human herpesvirus 6 levels were also assessed.

RESULTS

Among 85 infants, 43 had congenital infections and 42 had postnatal infections. Most congenital infections (86%) resulted from chromosomally integrated human herpesvirus 6; 6 infants (14%) had transplacental infections. Children with chromosomally integrated human herpesvirus 6 had high viral loads in all sites (mean: 5-6 log(10) genomic copies per mug of cellular DNA); among children with transplacental infection or postnatal infection, human herpesvirus 6 DNA was absent in hair samples and inconsistent in other samples, and viral loads were significantly lower. One parent of each child with chromosomally integrated human herpesvirus 6 who had parental hair samples tested had hair containing human herpesvirus 6 DNA. Variant A caused 32% of chromosomally integrated human herpesvirus 6 infections, compared with 2% of postnatal infections. Replicating human herpesvirus 6 was detected only among chromosomally integrated human herpesvirus 6 samples (8% of cord blood mononuclear cells and peripheral blood mononuclear cells). Cord blood human herpesvirus 6 antibody levels were similar among children with chromosomally integrated human herpesvirus 6, transplacental infection, and postnatal infection and between children with maternal and paternal chromosomally integrated human herpesvirus 6 transmission.

CONCLUSIONS

Human herpesvirus 6 congenital infection results primarily from chromosomally integrated virus which is passed through the germ-line. Infants with chromosomally integrated human herpesvirus 6 had high viral loads in all specimens, produced human herpesvirus 6 antibody, and mRNA. The clinical relevance needs study as 1 of 116 newborns may have chromosomally integrated human herpesvirus 6 blood specimens.

Education delays accelerated decline on a memory test in persons who develop dementia

OBJECTIVE

To test the cognitive reserve hypothesis by examining the effect of education on memory decline during the preclinical course of dementia.

BACKGROUND

Low education is a well known risk factor for Alzheimer disease (AD). Persons destined to develop AD experience an accelerated rate of decline in cognitive ability, particularly in memory. The cognitive reserve hypothesis predicts that persons with greater education begin to experience acceleration in cognitive decline closer to the time of diagnosis than persons with lower reserve, but that their rate of decline is more rapid after the time of acceleration due to increased disease burden.

METHODS

We studied the influence of education on rates of memory decline as measured by the Buschke Selective Reminding Test in 117 participants with incident dementia in the Bronx Aging Study. Subjects had detailed cognitive assessments at entry and at annual follow-up visits. We estimated the time at which the rate of decline begins to accelerate (the change point), and the pre- and post-acceleration rates of decline, from the longitudinal data using a change point model.

RESULTS

Each additional year of formal education delayed the time of accelerated decline on the Buschke Selective Reminding Test by 0.21 years. Post-acceleration, the rate of memory decline was increased by 0.10 points per year for each year of additional formal education.

CONCLUSIONS

As predicted by the cognitive reserve hypothesis, higher education delays the onset of accelerated cognitive decline; once it begins it is more rapid in persons with more education.

Human herpesvirus (HHV)-6 and HHV-7 infections in pregnant women

BACKGROUND

Both intrauterine and sexual transmission of human herpesvirus (HHV)-6 and HHV-7 have been suggested, and congenital HHV-6 infection does occur. We prospectively studied HHV-6 and HHV-7 at multiple sites in pregnant women to determine the characteristics of these viruses at repeated time points.

METHODS

Peripheral blood mononuclear cells (PBMCs), cervical secretions, placenta, and cord blood were tested by nested polymerase chain reaction (PCR) and reverse-transcriptase PCR for HHV-6 and HHV-7 and by quantitative PCR for HHV-6. A control group of women was also studied.

RESULTS

We enrolled 104 pregnant and 31 control women. HHV-7 DNA was detected more frequently in PBMCs from pregnant women (66.9%) than HHV-6 DNA (22.2%; P<.0001), but both were found at low rates in cervical swabs (HHV-7 vs. HHV-6 DNA, 3.0% vs. 7.5%; P=.19). Pregnant women with HHV-6 DNA present in cervical swabs had a greater odds of having HHV-6 DNA present in the blood than did pregnant women with negative cervical swabs (odds ratio, 12.9; P=.0009). HHV-6 reactivation or reinfection was suggested in 17% of pregnant women. One placental sample had active HHV-6 replication.

CONCLUSIONS

Detection of HHV-6 DNA in cervical secretions is associated with HHV-6 DNA in PBMC samples. Active placental infection along with congenital HHV-6 infection was identified.

Characteristics and Acquisition of Human Herpesvirus (HHV)–7 Infections in Relation to Infection with HHV‐6

Although both human herpesvirus (HHV) 6 and HHV-7 infections are ubiquitous during childhood, few acute HHV-7 infections are identified. It is unknown whether HHV-7 viremia indicates primary infection, as with HHV-6, or reactivation, and if these differ clinically. We studied, in otherwise healthy children < or =10 years old, HHV-7 and HHV-6 infections and their interaction by serologic assessment, viral isolation, and polymerase chain reaction. In children < or =24 months of age, HHV-7 infections occurred less often than HHV-6 infections (P< or =.002). Of 2806 samples from 2365 children < or =10 years old, 30 (1%) showed evidence of HHV-7 viremia; 23 (77%) of these were primary and 7 (23%) were reactivated HHV-7 infections. Four (13%) showed concurrent HHV-6 viremia, 2 associated with primary HHV-7 infections. The clinical manifestations of primary and reactivated HHV-7 infections were similar, except that seizures occurred more frequently in reactivated infections. These findings, previously unrecognized in otherwise healthy children, suggest that HHV-7 viremia could represent primary or reactivated infection and may be affected by the interaction between HHV-6 and HHV-7.

Identifying seizure clusters in patients with epilepsy

Clinicians often encounter patients whose neurologic attacks appear to cluster. In a daily diary study, the authors explored whether clustering is a true phenomenon in epilepsy and can be identified in the clinical setting. Nearly half the subjects experienced at least one episode of three or more seizures in 24 hours; 20% also met a statistical clustering criterion. Utilizing the clinical definition of clustering should identify all seizure clusterers, and false positives can be determined with diary data.

Dementia incidence may increase more slowly after age 90: results from the Bronx Aging Study

BACKGROUND

Dementia incidence increases dramatically from age 65 to age 85, with many studies reporting a doubling every 5 years. The incidence beyond age 85 is not established.

OBJECTIVE

To estimate the incidence of dementia as a function of age, with a particular focus on persons aged 85 and over.

METHODS

The Bronx Aging Study began in 1980 with 488 healthy, nondemented community-dwelling individuals, age 75 to 85. Persons in the study received clinical examinations and cognitive testing approximately every 12 months until death or loss to follow-up. The diagnosis of dementia was made using Diagnostic and Statistical Manual of Mental Disorders-III-R at diagnostic case conferences. Dementia incidence rates were calculated for 5-year age bands using person-time of follow-up as the denominator.

RESULTS

The relative incidence rate ratios of dementia for age 80 to 84 vs 75 to 79 was 2.32 (95% CI 1.23 to 4.37), the relative rate for age 85 to 89 vs 80 to 84 was 1.89 (95% CI 1.26 to 2.83), the relative rate for age 90 to 94 vs 85 to 89 was 1.49 (95% CI 0.86 to 2.58), while the relative rate for age 95 to 99 vs 90 to 94 was 1.31 (95% CI 0.38 to 4.46). Similar results were seen for men and women considered separately. Had the rate of increase from age 75 to 89 continued into the 90s, the study would have had 73% power to detect a significant difference between the rates for age 90 to 94 and 85 to 89 given the amount of observed follow-up time.

CONCLUSIONS

Whereas dementia incidence continues to increase beyond age 85, the rate of increase appears to slow relative to that of 65- to 85-year-olds. These results suggest that dementia in the oldest old might be related not to the aging process itself but with age-associated risk factors.

Low blood pressure and the risk of dementia in very old individuals

BACKGROUND

The role of blood pressure (BP) as a risk factor for dementia is complex and may be age dependent. In very old individuals, low BP might increase risk for dementia, perhaps by reducing cerebral perfusion pressure.

METHODS

The association between BP and dementia was examined in the Bronx Aging Study, a prospective study of 488 community-dwelling elderly individuals over age 75, dementia-free at baseline (1980 to 1983) and followed at 12- to 18-month intervals. Subjects with baseline BP and with at least one follow-up visit were included (n = 406). Incident dementia was diagnosed using the criteria of the Diagnostic and Statistical Manual of Mental Disorders (3rd rev. ed.).

RESULTS

Over 21 years (median 6.7 years), 122 subjects developed dementia (65 Alzheimer's disease [AD], 28 vascular dementia, 29 other dementias). Relative risk of dementia increased for each 10-mm Hg decrement in diastolic (hazard ratio [HR] 1.20, 95% CI 1.03 to 1.40) and mean arterial (HR 1.16, 95% CI 1.02 to 1.32) pressure, adjusted for age, sex, and education. Low diastolic BP significantly influenced risk of developing AD but not vascular dementia. Upon examination of groups defined by BP, mildly to moderately raised systolic BP (140 to 179 mm Hg) was associated with reduced risk for AD (HR vs normal systolic BP group 0.55, 95% CI 0.32 to 0.96), whereas low diastolic BP (<or=70 mm Hg) was associated with increased risk of AD (HR vs normal diastolic BP group 1.91, 95% CI 1.05 to 3.48). Subjects with persistent low BP over 2 years had higher risk of developing dementia (HR 2.19, 95% CI 1.27 to 3.77).

CONCLUSIONS

Low diastolic pressure is associated with higher risk of dementia in elderly individuals over age 75. Dementia risk was higher in subjects with persistently low BP.

Respiratory syncytial virus in healthy adults: the cost of a cold

Respiratory syncytial virus (RSV) is well recognized as a major pathogen of lower respiratory tract infection and hospitalization in young infants. More recently the pathogenicity of RSV has been demonstrated in elderly adults, institutionalized individuals, and those with compromised immune function. In these populations RSV spreads with ease and frequently results in severe or fatal cardiopulmonary complications. In younger, healthy adults, however, the manifestations and importance of RSV infection have been studied little, and RSV is generally not considered as a cause of respiratory illness in this healthy, working population. RSV occurs in yearly outbreaks and is highly contagious. Immunity after infection is neither complete nor durable. Repeated infections, therefore, occur throughout life. In most cases these recurrent infections involve the upper respiratory tract and thus do not receive a specific diagnosis. However, recent studies indicate that in the younger, healthy adult these respiratory illnesses tend to be more severe than the average 'cold' and may have manifestations similar to influenza. An appreciable proportion results in work absence. Thus, the emerging information suggests that RSV infection clearly occurs frequently in healthy adults in contact with children, but is generally not diagnosed. The potential burden on the healthcare system is unestimated, possibly unappreciated, and should be considered in strategies being developed for preventing RSV infection.

Estimation of bivariate measurements having different change points, with application to cognitive ageing

Longitudinal studies of ageing make repeated observations of multiple measurements on each subject. Change point models are often used to model longitudinal data. We demonstrate the use of Bayesian and profile likelihood methods to simultaneously estimate different change points in the longitudinal course of two different measurements of cognitive function in subjects in the Bronx Aging Study who developed Alzheimer's disease (AD). Analyses show that accelerated memory decline, as measured by Buschke Selective Reminding, begins between seven and eight years before diagnosis of AD, while decline in performance on speeded tasks as measured by WAIS Performance IQ begins slightly more than two years before diagnosis, significantly after the decline in memory.

Respiratory syncytial virus infections in previously healthy working adults

During 1975-1995, a total of 2960 healthy adults, 18-60 years of age, were prospectively evaluated for respiratory virus infections. Of these subjects, 211 (7%) acquired respiratory syncytial virus (RSV) infection. The infections were symptomatic in 84% of subjects, involved only the upper respiratory tract in 74%, and included lower respiratory tract symptoms in 26%. Overall, 40% of the subjects were febrile. Lower respiratory tract signs developed in 26%. RSV illnesses were more prolonged than non-RSV respiratory illnesses. Compared with influenza, RSV infections were less frequently associated with fever and headache, but were associated significantly more often with nasal congestion, ear and sinus involvement, and productive cough. Absence from work during the acute phase of the illness resulted from 38% of RSV infections and 66% of influenza cases. The mean duration of RSV illness (9.5 days), however, was significantly longer than that of influenza (6.8 days). The occurrence of annual epidemics of RSV, the virus' potential to reinfect all age groups, and the morbidity associated with these reinfections suggest that RSV infections in working adults may result in appreciable costs for medical visits and absence from work.

Diagnosing pediatric asthma: validating the Easy Breathing Survey

OBJECTIVE

To determine the sensitivity, specificity, and predictive value of a simple, self-administered questionnaire for the diagnosis of asthma in children.

STUDY DESIGN

A questionnaire specifically designed to assist primary care providers in making a diagnosis of asthma in children was developed and administered in 4 different primary care and subspecialty clinics, validated, and then used as part of an asthma management program called Easy Breathing. Asthma diagnoses were made according to recommended National Asthma Expert Panel Guidelines.

RESULTS

Four questions on the survey were shown to be sensitive and specific for asthma. The sensitivity was greater for all levels (mild, moderate, and severe) of persistent asthma than for mild, intermittent asthma. A positive response to any 1 of the 4 questions was over 94% sensitive for asthma; a negative response to all 4 questions was 55% specific for ruling out asthma.

CONCLUSIONS

Patient responses to 4 specific respiratory symptom questions can assist primary care providers in diagnosing asthma in children. Primary care providers serving pediatric populations at high risk for asthma should consider asking patients or their parents these 4 questions regarding asthma symptoms on a regular basis.

Validation of dual x-ray absorptiometry for body-composition assessment of rats exposed to dietary stressors

Evidence of the validity and accuracy of dual x-ray absorptiometry (DXA) to measure soft-tissue composition of laboratory rats with altered body composition associated with nutritional perturbations is lacking. We compared DXA determinations made in prone and supine positions with measurements of chemical composition of 49 male, weanling Sprague-Dawley rats that were fed the basal AIN-93 growth diet, were fed the basal diet modified to contain 30% fat, were fasted for 2 d, were limit fed 6 g of the basal diet daily for 1 wk, or were treated with furosemide (10 mg/kg intraperitoneally 2 h before DXA). DXA produced similar estimates of body mass and soft-tissue composition in the prone and supine positions. DXA estimates of body composition were significantly correlated with reference composition values (R(2) = 0.371-0.999). DXA discriminated treatment effects on body mass, fat-free and bone-free mass, fat mass, and body fatness; it significantly underestimated body mass (1% to 2%) and fat-free and bone-free mass (3%) and significantly overestimated fat mass and body fatness (3% to 25%). The greatest errors occurred in treatment groups in which body mass was diminished and body hydration was decreased. These findings suggest that DXA can determine small changes in fat-free, bone-free mass in response to obesity and weight loss. Errors in DXA determination of fat mass and body fatness associated with extra corporeal fluid and dehydration indicate the need for revision of calculation algorithms for soft-tissue determination.

Nosocomial respiratory syncytial virus infections: the "Cold War" has not ended

Respiratory syncytial virus (RSV) is a major nosocomial hazard on pediatric wards during its annual outbreaks. It produces significant morbidity in young children and is most severe in those with underlying conditions, especially cardiopulmonary and immunosuppressive diseases. In older patients, RSV may exacerbate an underlying condition or pulmonary and cardiac manifestations. On transplant units, of RSV may be occult and is associated with high mortality rates. The manifestations of nosocomial RSV infections may be atypical, especially in neonates and immunosuppressed patients, resulting in delayed or missed diagnosis and adding appreciably to the costs of hospitalization. RSV is primarily spread by close contact with infectious secretions, either by large-particle aerosols or by fomites and subsequent self-inoculation, and medical staff are often instrumental in its transmission. Thus, integral to any infection control program is the education of personnel about the modes of transmission, the manifestations, and the importance of RSV nosocomial infections. Hand washing is probably the most important infection control procedure. The choice of barrier controls should be decided by individual institutions depending on the patients, the type of ward, and the benefit relative to cost.

A change point model for estimating the onset of cognitive decline in preclinical Alzheimer's disease

Dementia is characterized by accelerated cognitive decline before and after diagnosis as compared to normal ageing. Determining the time at which that rate of decline begins to accelerate in persons who will develop dementia is important both in describing the natural history of the disease process and in identifying the optimal time window for which treatments might be useful. We model that time at which the rate of decline begins to accelerate in persons who develop dementia relative to those who do not by using a change point in a mixed linear model. A profile likelihood method is proposed to draw inferences about the change point. The method is applied to data from the Bronx Ageing Study, a cohort study of 488 initially non-demented community-dwelling elderly individuals who have been examined at approximately 12-month intervals over 15 years. Cognitive function was measured using the Buschke Selective Reminding test, a memory test with high reliability and known discriminative validity for detecting dementia. We found that the rate of cognitive decline as measured by this test in this cohort increases on average 5.1 years before the diagnosis of dementia.

Police reports on domestic incidents involving intimate partners: injuries and medical help-seeking

This study aims to expand knowledge of partner abuse injury and help-seeking through a new source of data. We reviewed police reports during corresponding periods in 1996 and 1997 (n = 476). Complainants were injured in 17.4% of all incidents; 90% of those injured were women. Hispanics were more likely to be injured than non-Hispanics (OR = 2.06; 95% CI = 1.0, 4.25). The likelihood of injury decreased with each year of increasing age (OR = 0.95; CI = 0.91, 0.99). Only 20.5% of those injured consented to medical care. Police reports provide information on partner abuse injury that supplements hospital surveillance and household surveys.

Circulation patterns of group A and B human respiratory syncytial virus genotypes in 5 communities in North America

Human respiratory syncytial virus (HRSV) is a major cause of serious lower respiratory tract illness in infants, young children, and the elderly. To characterize the circulation patterns of HRSV strains, nucleotide sequencing of the C-terminal region of the G protein gene was performed on 34-53 isolates obtained from 5 communities during 1 epidemic year, representing distinct geographical locations in North America. Phylogenetic analysis revealed that 5-7 HRSV genotypes, including 1 or 2 predominant strains, circulated in each community. The patterns of genotypes were distinct between communities, and less diversity was seen between strains of the same genotype within than between communities. These findings are consistent with HRSV outbreaks' being community based in nature, although transmission of viruses between communities may occur. Several strains are probably introduced or circulate endemically in communities each year, and local factors-possibly immunity induced by previous years' strains-determine which strains predominate during an HRSV season.

White matter abnormalities in mobility-impaired older persons

OBJECTIVE

To investigate the relationship between white matter abnormalities and impairment of gait and balance in older persons.

METHODS

Quantitative MRI was used to evaluate the brain tissue compartments of 28 older individuals separated into normal and impaired groups on the basis of mobility performance testing using the Short Physical Performance Battery. In addition, individuals were tested on six indices of gait and balance. For imaging data, segmentation of intracranial volume into four tissue classes was performed using template-driven segmentation, in which signal-intensity-based statistical tissue classification is refined using a digital brain atlas as anatomic template.

RESULTS

Both decreased white matter volume, which was age-related, and increased white matter signal abnormalities, which were not age-related, were observed in the mobility-impaired group compared with the control subjects. The average volume of white matter signal abnormalities for impaired individuals was nearly double that of control subjects.

CONCLUSIONS

This cross-sectional study suggests that decreased white matter volume is age-related, whereas increased white matter signal abnormalities are most likely to occur as a result of disease. Both of these changes are independently associated with impaired mobility in older persons and therefore likely to be additive factors of motor disability.

Respiratory syncytial virus and premature infants born at 32 weeks' gestation or earlier: hospitalization and economic implications of prophylaxis

OBJECTIVES

To assess the risk of hospitalization associated with respiratory syncytial virus (RSV) and to estimate the economic impact of RSV prophylaxis with either RSV immune globulin (RSV-Ig) or RSV monoclonal antibody (palivizumab) on a cohort of preterm infants born at 32 weeks' gestation or earlier.

DESIGN

Historical cohort study.

SETTING

A 12-county neonatal network served by the regional center in Rochester, NY.

PARTICIPANTS

One thousand twenty-nine infants born at 32 weeks' gestation or earlier followed up until 1 year of corrected age.

MAIN OUTCOME MEASURES

Rate of hospitalization with an RSV-associated illness; cost per hospitalization prevented resulting from either form of RSV prophylaxis.

RESULTS

The probability of hospitalization with an RSV-associated illness for infants born at 32 weeks' gestation or earlier was estimated at 11.2%. The incidence of RSV hospitalization increased with decreasing gestational age (13.9% vs 4.4% for infants born at < or =26 weeks' gestation vs those born at 30-32 weeks' gestation). Infants requiring respiratory support at 36 weeks of postconceptual age (PCA) or older had a higher hospitalization rate (16.8% vs 6.2%), longer hospital stays, and higher hospital charges than infants requiring respiratory support at less than 36 weeks of PCA. For infants requiring respiratory support at less than 36 weeks of PCA, the incidence of RSV hospitalization still increased with decreasing gestational age (10.2% vs 4.3% for infants < or =26 weeks' gestation vs those 30-32 weeks' gestation). Analysis indicated that both forms of RSV prophylaxis would increase the net cost of care for all groups. Palivizumab was more cost-effective than RSV-Ig for preventing RSV hospitalization among infants who required respiratory support at less than 36 weeks of PCA, especially those born at 26 weeks' gestation or earlier. Overall, RSV-Ig was more cost-effective than palivizumab for infants requiring respiratory support at 36 weeks of PCA or older.

CONCLUSIONS

This analysis suggests that available forms of RSV prophylaxis would increase the net cost of care not only for the entire cohort but for each of the subgroups studied. However, the RSV hospitalization rate and the cost-effectiveness of prophylaxis varied markedly by subgroup.