Abhishek Vishnu

Measurements of Airborne Influenza Virus in Aerosol Particles from Human Coughs

Influenza is thought to be communicated from person to person by multiple pathways. However, the relative importance of different routes of influenza transmission is unclear. To better understand the potential for the airborne spread of influenza, we measured the amount and size of aerosol particles containing influenza virus that were produced by coughing. Subjects were recruited from patients presenting at a student health clinic with influenza-like symptoms. Nasopharyngeal swabs were collected from the volunteers and they were asked to cough three times into a spirometer. After each cough, the cough-generated aerosol was collected using a NIOSH two-stage bioaerosol cyclone sampler or an SKC BioSampler. The amount of influenza viral RNA contained in the samplers was analyzed using quantitative real-time reverse-transcription PCR (qPCR) targeting the matrix gene M1. For half of the subjects, viral plaque assays were performed on the nasopharyngeal swabs and cough aerosol samples to determine if viable virus was present. Fifty-eight subjects were tested, of whom 47 were positive for influenza virus by qPCR. Influenza viral RNA was detected in coughs from 38 of these subjects (81%). Thirty-five percent of the influenza RNA was contained in particles >4 µm in aerodynamic diameter, while 23% was in particles 1 to 4 µm and 42% in particles <1 µm. Viable influenza virus was detected in the cough aerosols from 2 of 21 subjects with influenza. These results show that coughing by influenza patients emits aerosol particles containing influenza virus and that much of the viral RNA is contained within particles in the respirable size range. The results support the idea that the airborne route may be a pathway for influenza transmission, especially in the immediate vicinity of an influenza patient. Further research is needed on the viability of airborne influenza viruses and the risk of transmission.

Mind-body therapies for menopausal symptoms: a systematic review.

OBJECTIVE To systematically review the peer-reviewed literature regarding the effects of self-administered mind-body therapies on menopausal symptoms. METHODS To identify qualifying studies, we searched 10 scientific databases and scanned bibliographies of relevant review papers and all identified articles. The methodological quality of all studies was assessed systematically using predefined criteria. RESULTS Twenty-one papers representing 18 clinical trials from 6 countries met our inclusion criteria, including 12 randomized controlled trials (N=719), 1 non-randomized controlled trial (N=58), and 5 uncontrolled trials (N=105). Interventions included yoga and/or meditation-based programs, tai chi, and other relaxation practices, including muscle relaxation and breath-based techniques, relaxation response training, and low-frequency sound-wave therapy. Eight of the nine studies of yoga, tai chi, and meditation-based programs reported improvement in overall menopausal and vasomotor symptoms; six of seven trials indicated improvement in mood and sleep with yoga-based programs, and four studies reported reduced musculoskeletal pain. Results from the remaining nine trials suggest that breath-based and other relaxation therapies also show promise for alleviating vasomotor and other menopausal symptoms, although intergroup findings were mixed. Most studies reviewed suffered methodological or other limitations, complicating interpretation of findings. CONCLUSIONS Collectively, findings of these studies suggest that yoga-based and certain other mind-body therapies may be beneficial for alleviating specific menopausal symptoms. However, the limitations characterizing most studies hinder interpretation of findings and preclude firm conclusions regarding efficacy. Additional large, methodologically sound trials are needed to determine the effects of specific mind-body therapies on menopausal symptoms, examine long-term outcomes, and investigate underlying mechanisms.

Viable Influenza A Virus in Airborne Particles from Human Coughs

Patients with influenza release aerosol particles containing the virus into their environment. However, the importance of airborne transmission in the spread of influenza is unclear, in part because of a lack of information about the infectivity of the airborne virus. The purpose of this study was to determine the amount of viable influenza A virus that was expelled by patients in aerosol particles while coughing. Sixty-four symptomatic adult volunteer outpatients were asked to cough 6 times into a cough aerosol collection system. Seventeen of these participants tested positive for influenza A virus by viral plaque assay (VPA) with confirmation by viral replication assay (VRA). Viable influenza A virus was detected in the cough aerosol particles from 7 of these 17 test subjects (41%). Viable influenza A virus was found in the smallest particle size fraction (0.3 μm to 8 μm), with a mean of 142 plaque-forming units (SD 215) expelled during the 6 coughs in particles of this size. These results suggest that a significant proportion of patients with influenza A release small airborne particles containing viable virus into the environment. Although the amounts of influenza A detected in cough aerosol particles during our experiments were relatively low, larger quantities could be expelled by influenza patients during a pandemic when illnesses would be more severe. Our findings support the idea that airborne infectious particles could play an important role in the spread of influenza.

The severity of the metabolic syndrome increases over time within individuals, independent of baseline metabolic syndrome status and medication use: The Atherosclerosis Risk in Communities Study

BACKGROUND AND AIMS The severity of the metabolic syndrome (MetS) is linked to future cardiovascular disease. However, it is unclear whether MetS severity increases among individuals followed over time. METHODS We assessed changes in a sex- and race/ethnicity-specific MetS severity Z-score over a 10-year period (visits 1-4) among 9291 participants of the Atherosclerosis Risk in Communities study cohort. We compared sex- and racial/ethnic subgroups for the rate of change in the MetS severity score and MetS prevalence as assessed using traditional ATP-III MetS criteria. We further examined effects of use of medications for hypertension, diabetes and dyslipidemia. RESULTS Over the 10 years of follow-up, MetS severity Z-scores increased in 76% of participants from an overall mean of 0.08 ± 0.77 at baseline to 0.48 ± 0.96 at visit 4 with the greatest progression in scores observed among African-American women. Baseline MetS severity scores predicted the time until ATP-III MetS diagnosis, with a model-predicted 77.5% of individuals with a visit 1 MetS severity score of 0.75 progressing to ATP-III MetS within 10 years. The rate of increase in MetS severity score was higher among those younger at baseline but was independent of baseline MetS status or the use of medications to treat blood pressure, lipids and diabetes. CONCLUSION The severity of metabolic derangements as measured using this MetS severity score increases over time within individuals and predicts diagnosis of ATP-III MetS. These data may have implications for tracking MetS related risk within individuals over time.

Progression of Metabolic Syndrome Severity During the Menopausal Transition

Background After menopause, women exhibit a higher prevalence of the metabolic syndrome (MetS) and higher risk of cardiovascular disease. However, the timing of changes in MetS severity over the menopausal transition and whether these changes differ by racial/ethnic group remain unclear. Methods and Results We assessed data from 1470 women from the Atherosclerosis Risk in Communities cohort who experienced transition in menopausal status over 10 years (visits 1–4). We used linear mixed models to evaluate changes by menopausal status (premenopause, perimenopause, and postmenopause) in a MetS severity Z‐score and in the individual MetS components. While there were gradual increases in MetS severity over time across menopause stages, black women in particular exhibited more rapid progression in MetS severity during the premenopausal and perimenopausal periods than during the postmenopausal period. In the postmenopausal period (compared with prior periods), white women exhibited unfavorable decreases in high‐density lipoprotein, while black women exhibited favorable alterations in the rate of change for waist circumference, triglycerides, high‐density lipoprotein, and glucose, contributing to the slowed progression of MetS severity. These changes were all observed after adjusting for hormone replacement treatment. Conclusions During menopausal transition, women exhibited rapid increases in MetS severity during the premenopausal and perimenopausal periods, with black women having significant reductions in this increase in severity during the postmenopausal period. These data suggest that the higher prevalence of MetS in postmenopausal women may be caused more by changes during the menopausal transition than by postmenopause. These findings may thus have implications regarding the timing of cardiovascular risk relative to menopause.

Examination of the Association between Insufficient Sleep andCardiovascular Disease and Diabetes by Race/Ethnicity

Background. We examined the association between insufficient rest/sleep and cardiovascular disease or diabetes mellitus separately among non-Hispanic whites, non-Hispanic blacks, Hispanic Americans, and other races in a contemporary sample of US adults. Methods. Multiethnic, nationally representative, cross-sectional survey (2008 BRFSS) participants who were >20 years of age (n = 369, 217; 50% women). Self-reported insufficient rest/sleep in the previous month was categorized into: zero, 1–13, 14–29, and all 30 days. Outcomes were: (1) any CVD, (2) coronary artery disease (CHD), (3) stroke, and (4) diabetes mellitus. Results. Insufficient rest/sleep was found to be positively associated with (1) any CVD, (2) CHD, and (3) stroke among all race-ethnicities. In contrast, insufficient rest/sleep was positively associated with diabetes mellitus in all race-ethnicities except non-Hispanic blacks. The odds ratio of diabetes association with insufficient rest/sleep for all 30 days was 1.37 (1.26–1.48) among non-Hispanic whites, 1.11 (0.90–1.36) among non-Hispanic blacks, 1.88 (1.46–2.42) among Hispanic Americans, and 1.48 (1.10–2.00) among other race/ethnicities. Conclusion. In a multiethnic sample of US adults, perceived insufficient rest/sleep was associated with CVD, among all race-ethnicities. However, the association between insufficient rest/sleep and diabetes mellitus was present among all race-ethnicities except non-Hispanic blacks.

Independent Associations Between Metabolic Syndrome Severity and Future Coronary Heart Disease by Sex and Race

There has been controversy whether the metabolic syndrome (MetS) provides additional risk prediction beyond that conferred by levels of the individual MetS components of waist circumference, blood pressure, fasting triglycerides, low high-density lipoprotein, and fasting glucose [(1)][1]. We

Brachial-ankle pulse wave velocity is associated with coronary calcification among 1131 healthy middle-aged men

BACKGROUND Brachial-ankle pulse wave velocity (baPWV) is a simple and reproducible measure of arterial stiffness and is extensively used to assess cardiovascular disease (CVD) risk in eastern Asia. We examined whether baPWV is associated with coronary atherosclerosis in an international study of healthy middle-aged men. METHODS A population-based sample of 1131 men aged 40-49 years was recruited - 257 Whites and 75 Blacks in Pittsburgh, US, 228 Japanese-Americans in Honolulu, US, 292 Japanese in Otsu, Japan, and 279 Koreans in Ansan, Korea. baPWV was measured with an automated waveform analyzer (VP2000, Omron) and atherosclerosis was examined as coronary artery calcification (CAC) by computed-tomography (GE-Imatron EBT scanner). Association of the presence of CAC (defined as ≥ 10 Agatston unit) was examined with continuous measure as well as with increasing quartiles of baPWV. RESULTS As compared to the lowest quartile of baPWV, the multivariable-adjusted odds ratio (95% Confidence Interval [CI]) for the presence of CAC in the combined sample was 1.70 (0.98, 2.94) for 2nd quartile, 1.88 (1.08, 3.28) for 3rd quartile, and 2.16 (1.19, 3.94) for 4th quartile (p-trend = 0.01). The odds for CAC increased by 19% per 100 cm/s increase (p < 0.01), or by 36% per standard-deviation increase (p < 0.01) in baPWV. Similar effect-sizes were observed in individual races, and were significant among Whites, Blacks and Koreans. CONCLUSION baPWV is cross-sectionally associated with CAC among healthy middle-aged men. The association was significant in Whites and Blacks in the US, and among Koreans. Longitudinal studies are needed to determine its CVD predictive ability.

Depressive symptoms are associated with worsened severity of the metabolic syndrome in African American women independent of lifestyle factors: A consideration of mechanistic links from the Jackson heart study.

BACKGROUND Depression and the metabolic syndrome (MetS) are both risk factors for cardiovascular disease and type 2 diabetes mellitus. Prior studies in predominantly White populations demonstrated that individuals with depressive symptoms at baseline are more likely to develop future MetS. We tested the hypothesis that depressive symptoms would contribute to a more pronounced increase in MetS severity among African Americans in the Jackson Heart Study (JHS). METHODS We used repeated-measures modeling among 1743 JHS participants during Visits 1-3 over 8 years of follow-up to evaluate relations between depressive symptom score (Center for Epidemiologic Survey-Depression (CES-D)) at baseline and a sex- and race/ethnicity-specific MetS severity Z-score at each visit. RESULTS 20.3% of participants had a CES-D score ≥16, consistent with clinically-relevant depressive symptoms. Higher depressive-symptom scores were associated with higher MetS severity in women but not men (p=0.005 vs. p=0.490). There was no difference by depressive symptom score with rate of change in MetS severity over time. Both depressive-symptom score and MetS severity Z-score were associated with lower levels of physical activity and higher levels of C-reactive protein; however, addition of these to the regression model did not attenuate the association between depressive symptoms and MetS severity. CONCLUSION African American women but not men in the JHS exhibit relationships between baseline depressive symptoms and MetS severity over an 8-year period. These data may have implications for targeting of MetS-associated lifestyle changes among individuals with depressive symptoms.

The impact of equol-producing status in modifying the effect of soya isoflavones on risk factors for CHD: a systematic review of randomised controlled trials

Recent studies suggest that the ability to produce equol, a metabolite of the soya isoflavone daidzein, is beneficial to coronary health. Equol, generated by bacterial action on isoflavones in the human gut, is biologically more potent than dietary sources of isoflavones. Not all humans are equol producers. We investigated whether equol-producing status is favourably associated with risk factors for CHD following an intervention by dietary soya isoflavones. We systematically reviewed randomised controlled trials (RCT) that evaluated the effect of soya isoflavones on risk factors for CHD and that reported equol-producing status. We searched PubMed, EMBASE, Ovid Medline and the Cochrane Central Register for Controlled Trials published up to April 2015 and hand-searched bibliographies to identify the RCT. Characteristics of participants and outcomes measurements were extracted and qualitatively analysed. From a total of 1671 studies, we identified forty-two articles that satisfied our search criteria. The effects of equol on risk factors for CHD were mainly based on secondary analyses in these studies, thus with inadequate statistical power. Although fourteen out of the forty-two studies found that equol production after a soya isoflavone intervention significantly improved a range of risk factors including cholesterol and other lipids, inflammation and blood pressure variables, these results need further verification by sufficiently powered studies. The other twenty-eight studies primarily reported null results. RCT of equol, which has recently become available as a dietary supplement, on CHD and its risk factors are awaited.