Investigating the nexus of metabolic syndrome, serum uric acid, and dementia risk: a prospective cohort study.

BACKGROUND: The global dementia prevalence is surging, necessitating research into contributing factors. We aimed to investigate the association between metabolic syndrome (MetS), its components, serum uric acid (SUA) levels, and dementia risk. METHODS: Our prospective study comprised 466,788 participants without pre-existing MetS from the UK Biobank. We confirmed dementia diagnoses based on the ICD-10 criteria (F00-03). To evaluate the dementia risk concerning MetS, its components, and SUA levels, we applied Cox proportional hazards models, while adjusting for demographic factors. RESULTS: Over a median follow-up of 12.7 years, we identified 6845 dementia cases. Individuals with MetS had a 25% higher risk of all-cause dementia (hazard ratio [HR] = 1.25, 95% confidence interval [CI] = 1.19-1.31). The risk increased with the number of MetS components including central obesity, dyslipidemia for high-density lipoprotein (HDL) cholesterol, hypertension, hyperglycemia, and dyslipidemia for triglycerides. Particularly for those with all five components (HR = 1.76, 95% CI = 1.51-2.04). Dyslipidemia for HDL cholesterol, hypertension, hyperglycemia, and dyslipidemia for triglycerides were independently associated with elevated dementia risk (p < 0.01). MetS was further linked to an increased risk of all-cause dementia (11%) and vascular dementia (VD, 50%) among individuals with SUA levels exceeding 400 µmol/L (all-cause dementia: HR = 1.11, 95% CI = 1.02-1.21; VD: HR = 1.50, 95% CI = 1.28-1.77). CONCLUSIONS: Our study provides robust evidence supporting the association between MetS, its components, and dementia risk. These findings emphasize the importance of considering MetS and SUA levels in assessing dementia risk, offering valuable insights for prevention and management strategies.

Number of natural teeth, denture use and mortality in Chinese elderly: a population-based prospective cohort study.

BACKGROUND: The associations between the number of natural teeth/denture use and all-cause mortality remain unclear due to lake of investigation for the potential interaction between tooth loss and denture use and for the potential changes in these exposures over time in older adults. We undertake this study to evaluate the associations of the number of natural teeth and/or denture use with mortality in Chinese elderly. METHODS: This is a prospective cohort study of 36,283 older adults (median age: 90). The number of natural teeth and denture use were collected with structured questionnaire. We evaluated hazard ratios (HRs) and confidence intervals (CIs) using a Cox proportional hazards model adjusting for demographic factors, education, income, lifestyle factors, and comorbidities. RESULTS: We documented 25,857 deaths during 145,947 person-years of observation. Compared to those with 20+ teeth, tooth loss was associated with a gradual increase in mortality, with an adjusted HR of 1.14 (95% CI, 1.06 to 1.23) for those with 10-19 teeth, 1.23 (95% CI, 1.15 to 1.31) for those with 1-9 teeth, and 1.35 (95% CI, 1.26 to 1.44) for those without natural teeth. Denture use was associated with lower risk of mortality (adjusted HR 0.81; 95% CI, 0.77 to 0.84). Subgroup analyses indicated that the benefit of denture use was greater in men than in women (P = 0.02) and tended to decrease with age (P < 0.001). The effects of denture use did not differ among various degrees of tooth loss (P = 0.17). CONCLUSIONS: Tooth loss was associated with an increased risk of mortality in older adults. Denture use provided a protective effect against death for all degrees of tooth loss however, this effect appeared to be modified by sex and age.

Plasma 25-Hydroxyvitamin D Concentrations Are Inversely Associated with All-Cause Mortality among a Prospective Cohort of Chinese Adults Aged ≥80 Years.

BACKGROUND: High concentrations of plasma 25-hydroxyvitamin D [25(OH)D], a marker of circulating vitamin D, have been associated with a lower risk of mortality in epidemiologic studies of multiple populations, but the association for Chinese adults aged ≥80 y (oldest old) remains unclear. OBJECTIVE: We investigated the association between plasma [25(OH)D] concentration and all-cause mortality among Chinese adults aged ≥80 y. DESIGN: The present study is a prospective cohort study of 2185 Chinese older adults (median age: 93 y). Prospective all-cause mortality data were analyzed for survival in relation to plasma 25(OH)D using Cox proportional hazards regression models, with adjustments for potential sociodemographic and lifestyle confounders and biomarkers. The associations were measured with HR and 95% CIs. RESULTS: The median plasma 25(OH)D concentration was 34.4 nmol/L at baseline. Over the 5466 person-year follow-up period, 1100 deaths were identified. Men and women were analyzed together as no effect modification by sex was found. After adjusting for multiple potential confounders, the risk of all-cause mortality decreased as the plasma 25(OH)D concentration increased (P-trend <0.01). Compared with the lowest age-specific quartile of plasma 25(OH)D, the adjusted HRs for mortality for the second, third, and fourth age-specific quartiles were 0.72 (95% CI: 0.57, 0.90), 0.73 (95% CI: 0.58, 0.93), and 0.61 (95% CI: 0.47, 0.81), respectively. The observed associations were broadly consistent across age and other subgroups. Sensitivity analyses generated similar results after excluding participants who died within 2 y of follow-up or after further adjustment for ethnicity and chronic diseases. CONCLUSIONS: A higher plasma 25-hydroxyvitamin D concentration was associated with a reduced risk of all-cause mortality among Chinese adults aged ≥80 y. This observed inverse association warrants further investigation in randomized controlled trials testing vitamin D supplementation in this age group.

Associations between superoxide dismutase, malondialdehyde and all-cause mortality in older adults: a community-based cohort study.

BACKGROUND: Oxidative stress is an important theory of aging but population-based evidence has been lacking. This study aimed to evaluate the associations between biomarkers of oxidative stress, including plasma superoxide dismutase (SOD) activity and malondialdehyde (MDA), with all-cause mortality in older adults. METHODS: This is a community-based cohort study of 2224 participants (women:1227, median age: 86 years). We included individuals aged 65 or above and with plasma SOD activity and/or MDA tests at baseline. We evaluated the hazard ratios (HRs) and 95% confidence intervals (CIs) by multivariable Cox models. RESULTS: We documented 858 deaths during six years of follow-up. There was a significant interaction effect of sex with the association between SOD activity and mortality (P < 0.001). Compared with the lowest quintile, the risk of all-cause mortality was inversely associated with increasing quintiles of plasma SOD activity in women(P-trend< 0.001), with adjusted HRs for the second through fifth quintiles of 0.73 (95% CI 0.53-1.02), 0.52(95% CI 0.38-0.72), 0.53(95% CI 0.39-0.73), and 0.48(95% CI 0.35-0.66). There were no significant associations between SOD activity and mortality in men (P-trend = 0.64), and between MDA and mortality in all participants (P-trend = 0.79). CONCLUSIONS: Increased activity of SOD was independently associated with lower all-cause mortality in older women but not in men. This epidemiological study lent support for the free radical/oxidative stress theory of aging.

Phototherapy for treating foot ulcers in people with diabetes.

BACKGROUND: Foot ulcers are a disabling complication of diabetes that affect 15% to 25% of people with diabetes at some time in their lives. Phototherapy is a relatively new, non-invasive, and pain-free treatment method, which promotes the ulcer repair process through multiple mechanisms such as increased cell growth and vascular activity. Phototherapy may be used as an alternative approach for the treatment of foot ulcers in people with diabetes, but the evidence for its effect compared with placebo or other treatments has not yet been established. OBJECTIVES: To assess the effects of phototherapy for the treatment of foot ulcers in people with diabetes. SEARCH METHODS: We searched the Cochrane Wounds Specialised Register (11 October 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2016, Issue 10), Ovid MEDLINE (11 October 2016), Ovid MEDLINE (In-Process & Other Non-Indexed Citations) (11 October 2016), Ovid Embase (11 October 2016), EBSCO CINAHL Plus (11 October 2016), and China National Knowledge Infrastructure (24 June 2017). We also searched clinical trials registries for ongoing and unpublished studies on 24 June 2017, and screened reference lists to identify additional studies. We used no restrictions with respect to language, date of publication, or study setting. SELECTION CRITERIA: Randomised controlled trials or cluster randomised controlled trials that 1) compared phototherapy with sham phototherapy, no phototherapy, or other physical therapy modalities, 2) compared different forms of phototherapy, or 3) compared phototherapy of different output power, wavelength, power density, or dose range, in adults with diabetes and an open foot ulcer of any severity, in any setting. DATA COLLECTION AND ANALYSIS: Two review authors independently performed study selection, data extraction, and 'Risk of bias' assessment. We combined the study outcomes when appropriate. MAIN RESULTS: Eight trials with 316 participants met the inclusion criteria. Most of the included studies were single-centre studies that were carried out in clinics or hospitals with a sample size ranging from 14 to 84. We generally considered the included studies to be at unclear or high risk of bias, as they had one domain at high risk of bias, or three or more domains at unclear risk of bias.We did not identify any studies that reported valid data for time to complete wound healing. Meta-analysis of four studies including 116 participants indicated that participants receiving phototherapy may experience a greater proportion of wounds completely healed during follow-up compared with those receiving no phototherapy/placebo (64.5% for the phototherapy group versus 37.0% for the no phototherapy/placebo group; risk ratio 1.57, 95% confidence interval 1.08 to 2.28; low-quality evidence, downgraded for study limitations and imprecision). Two studies mentioned adverse events in the results; one study with 16 participants suggested that there were no device-related adverse events, and the other study with 14 participants suggested that there was no clear difference between phototherapy and placebo group.Four studies reported change in ulcer size, but primarily due to high heterogeneity, they were not combined. Results from individual trials (including 16 participants to 84 participants) generally suggested that after two to four weeks of treatment phototherapy may result in a greater reduction in ulcer size but the quality of the evidence was low due to unclear risk of bias in the original trial and small sample size. We based the analyses for quality of life and amputations on only one study each (28 participants and 23 participants respectively); both outcomes showed no clear difference between the phototherapy group and the no phototherapy/placebo group. AUTHORS' CONCLUSIONS: This systematic review of randomised trials suggested that phototherapy, when compared to no phototherapy/placebo, may increase the proportion of wounds completely healed during follow-up and may reduce wound size in people with diabetes, but there was no evidence that phototherapy improves quality of life. Due to the small sample size and methodological flaws in the original trials, the quality of the evidence was low, which reduces our confidence in these results. Large, well-designed randomised controlled trials are needed to confirm whether phototherapy could be an effective option for the treatment of foot ulcers in people with diabetes.

Yoga for asthma.

BACKGROUND: Asthma is a common chronic inflammatory disorder affecting about 300 million people worldwide. As a holistic therapy, yoga has the potential to relieve both the physical and psychological suffering of people with asthma, and its popularity has expanded globally. A number of clinical trials have been carried out to evaluate the effects of yoga practice, with inconsistent results. OBJECTIVES: To assess the effects of yoga in people with asthma. SEARCH METHODS: We systematically searched the Cochrane Airways Group Register of Trials, which is derived from systematic searches of bibliographic databases including the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, AMED, and PsycINFO, and handsearching of respiratory journals and meeting abstracts. We also searched PEDro. We searched ClinicalTrials.gov and the WHO ICTRP search portal. We searched all databases from their inception to 22 July 2015, and used no restriction on language of publication. We checked the reference lists of eligible studies and relevant review articles for additional studies. We attempted to contact investigators of eligible studies and experts in the field to learn of other published and unpublished studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) that compared yoga with usual care (or no intervention) or sham intervention in people with asthma and reported at least one of the following outcomes: quality of life, asthma symptom score, asthma control, lung function measures, asthma medication usage, and adverse events. DATA COLLECTION AND ANALYSIS: We extracted bibliographic information, characteristics of participants, characteristics of interventions and controls, characteristics of methodology, and results for the outcomes of our interest from eligible studies. For continuous outcomes, we used mean difference (MD) with 95% confidence interval (CI) to denote the treatment effects, if the outcomes were measured by the same scale across studies. Alternatively, if the outcomes were measured by different scales across studies, we used standardised mean difference (SMD) with 95% CI. For dichotomous outcomes, we used risk ratio (RR) with 95% CI to measure the treatment effects. We performed meta-analysis with Review Manager 5.3. We used the fixed-effect model to pool the data, unless there was substantial heterogeneity among studies, in which case we used the random-effects model instead. For outcomes inappropriate or impossible to pool quantitatively, we conducted a descriptive analysis and summarised the findings narratively. MAIN RESULTS: We included 15 RCTs with a total of 1048 participants. Most of the trials were conducted in India, followed by Europe and the United States. The majority of participants were adults of both sexes with mild to moderate asthma for six months to more than 23 years. Five studies included yoga breathing alone, while the other studies assessed yoga interventions that included breathing, posture, and meditation. Interventions lasted from two weeks to 54 months, for no more than six months in the majority of studies. The risk of bias was low across all domains in one study and unclear or high in at least one domain for the remainder.There was some evidence that yoga may improve quality of life (MD in Asthma Quality of Life Questionnaire (AQLQ) score per item 0.57 units on a 7-point scale, 95% CI 0.37 to 0.77; 5 studies; 375 participants), improve symptoms (SMD 0.37, 95% CI 0.09 to 0.65; 3 studies; 243 participants), and reduce medication usage (RR 5.35, 95% CI 1.29 to 22.11; 2 studies) in people with asthma. The MD for AQLQ score exceeded the minimal clinically important difference (MCID) of 0.5, but whether the mean changes exceeded the MCID for asthma symptoms is uncertain due to the lack of an established MCID in the severity scores used in the included studies. The effects of yoga on change from baseline forced expiratory volume in one second (MD 0.04 litres, 95% CI -0.10 to 0.19; 7 studies; 340 participants; I(2) = 68%) were not statistically significant. Two studies indicated improved asthma control, but due to very significant heterogeneity (I(2) = 98%) we did not pool data. No serious adverse events associated with yoga were reported, but the data on this outcome was limited. AUTHORS' CONCLUSIONS: We found moderate-quality evidence that yoga probably leads to small improvements in quality of life and symptoms in people with asthma. There is more uncertainty about potential adverse effects of yoga and its impact on lung function and medication usage. RCTs with a large sample size and high methodological and reporting quality are needed to confirm the effects of yoga for asthma.

Interleukin-2 as maintenance therapy for children and adults with acute myeloid leukaemia in first complete remission.

BACKGROUND: Acute myeloid leukaemia (AML) is a malignant cancer of hematopoietic stem cells. The treatment of AML consists of two treatment phases: the remission induction phase to achieve a rapid, complete remission (CR) and the consolidation phase to achieve a durable molecular remission. People in CR are at risk of AML relapse, and people with relapsed AML have poor survival prospects. Thus, there is a continuous need for treatments to further improve prognosis. Interleukin-2 (IL-2), an immune-stimulatory cytokine, is an alternative to standard treatment for people with AML to maintain the efficacy after consolidation therapy. Maintenance therapy is not an integral part of the standard treatment for AML. Studies have been conducted to evaluate the efficacy of IL-2 as maintenance therapy for people with AML in first CR, but the effect of IL-2 is not yet fully established. OBJECTIVES: To evaluate the efficacy and safety of IL-2 as maintenance therapy for children and adults with AML who have achieved first CR and have not relapsed. SEARCH METHODS: We systematically searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library 2015, Issue 8), MEDLINE (1950 to August 2015), EMBASE (1950 to August 2015), LILACS (1982 to August 2015), CBM (1978 to August 2015), relevant conference proceedings (2000 to 2015), and metaRegister of Controlled Trials (since inception to August 2015) of ongoing and unpublished trials. In addition, we screened the reference lists of relevant trials and reviews. SELECTION CRITERIA: Eligible studies were randomised controlled trials (RCTs) comparing IL-2 with no treatment in people with AML who had achieved first CR and had not relapsed. We did not identify studies comparing IL-2 versus best supportive care or maintenance chemotherapy or studies comparing IL-2 plus maintenance chemotherapy versus maintenance chemotherapy alone. DATA COLLECTION AND ANALYSIS: Two review authors independently screened studies, extracted data with a predefined extraction form, and assessed risk of bias of included studies. We extracted data on the following outcomes: disease-free survival, overall survival, event-free survival, treatment-related mortality, adverse events, and quality of life. We measured the treatment effect on time-to-event outcomes and dichotomous outcomes with hazard ratio (HR) and risk ratio, respectively. We used inverse-variance method to combine HRs with fixed-effect model unless there was significant between-study heterogeneity. MAIN RESULTS: We included nine RCTs with a total of 1665 participants, comparing IL-2 with no treatment. Six studies included adult participants, and three studies included both adults and children. However, the latter three studies did not report data for children, thus we were unable to conduct subgroup analysis of children. One Chinese study did not report any outcomes of interest for this review. We included six trials involving 1426 participants in the meta-analysis on disease-free survival, and included five trials involving 1355 participants in the meta-analysis on overall survival. There is no evidence for difference between IL-2 group and no-treatment group regarding disease-free survival (HR 0.95; 95% CI 0.86 to 1.06, P = 0.37; quality of evidence: low) or overall survival (HR 1.05; 95% CI 0.95 to 1.16, P = 0.35; quality of evidence: moderate). Based on one trial of 161 participants, IL-2 exerted no effect on event-free survival (HR 1.02; 95% CI 0.79 to 1.32, P = 0.88; quality of evidence: low). Adverse events (including thrombocytopenia, neutropenia, malaise/fatigue, and infection/fever) were more frequent in participants receiving IL-2, according to one trial of 308 participants. No mortality due to adverse events was reported. None of the included studies reported treatment-related mortality or quality of life. AUTHORS' CONCLUSIONS: There is no evidence for a difference between IL-2 maintenance therapy and no treatment with respect to disease-free survival or overall survival of people with AML in first CR; however, the quality of the evidence is moderate or low, and further research is likely or very likely to have an important impact on the estimate or our confidence in the estimate. Adverse events seem to be more frequent in participants treated with IL-2, but the quality of the evidence is very low and our confidence in the estimates is very uncertain. Thus, further prospective randomised trials are needed before definitive conclusions can be drawn on these issues.

Tong-xin-luo capsule for patients with coronary heart disease after percutaneous coronary intervention.

BACKGROUND: Percutaneous coronary intervention (PCI) is a standard treatment for coronary heart disease (CHD). Restenosis, defined as a 50% reduction in luminal diameter at six months after PCI, indicates a need for revascularisation. Restenosis has proven to be a major drawback to PCI. Tong-xin-luo is one of the prophylactic strategies for cardiovascular events in patients after PCI that is widely used in China, but its efficacy and safety have not been systematically evaluated. OBJECTIVES: To systematically assess the efficacy and safety of Tong-xin-luo capsules in preventing cardiovascular events after PCI in patients with CHD. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE (OVID), EMBASE (OVID), WanFang, Chinese Biomedical Database, Chinese Medical Current Contents, and China National Knowledge Infrastructure from their inception to June 2014. We also searched other resources, including ongoing trials and research registries. We applied no language restrictions. SELECTION CRITERIA: Randomised controlled trials of participants with CHD after PCI were included. Participants in the intervention group received Tong-xin-luo capsules for at least three months. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and assessed the risk of bias. Any disagreements were resolved by discussion with a third review author. The primary outcomes included occurrence of angiographic restenosis and adverse events; the secondary outcomes included myocardial infarction, heart failure, angina, all cause mortality, mortality due to any cardiovascular event, use of revascularisation, patient acceptability, quality of life and cost-effectiveness. Dichotomous data were measured with risk ratios (RRs) with 95% confidence intervals (CIs). MAIN RESULTS: Sixteen studies involving 1063 participants were identified. The risk of bias for fifteen studies was high and along with imprecision and possible publication bias, this lowered our confidence in the results. There was low quality evidence that Tong-xi-luo reduced the rates of angiographic restenosis (RR 0.16, 95% CI 0.07 to 0.34), myocardial infarction (RR 0.32, 95% CI 0.16 to 0.66), heart failure (RR 0.26, 95% CI 0.11 to 0.62), and use of revascularisation (RR 0.26, 95% CI 0.15 to 0.45). There was very low quality evidence for the effect of Tong-xin-luo on all-cause mortality (RR 0.38, 95% CI 0.06 to 2.56), angina (RR 0.24, 95% CI 0.17 to 0.34) and death due to any cardiovascular event (RR 0.31, 95% CI 0.08 to 1.12). Adverse events were seldom reported, and included gastrointestinal reactions and nausea. AUTHORS' CONCLUSIONS: The addition of Tong-xin-luo to conventional Western medicine may possibly prevent restenosis and recurrence of cardiovascular events in patients with CHD after PCI. However, the data are limited by publication bias and high risk of bias for included studies. Further high-quality trials are required to evaluate the potential effects of this intervention.

Transarterial chemoembolization combined with sorafenib for unresectable hepatocellular carcinoma: a systematic review and meta-analysis.

Sorafenib in combination with Transarterial chemoembolization (TACE) is increasingly used in patients with unresectable hepatocellular carcinoma (HCC), but the current evidence is still controversial. The aim of this systematic review was to evaluate the effectiveness and safety of TACE plus sorafenib versus TACE alone for unresectable HCC. We searched PubMed, EMBASE and the Cochrane Library for clinical trials comparing TACE plus sorafenib with TACE alone for unresectable HCC. The study outcomes included overall survival (OS), time to progression (TTP), objective response and adverse events (AEs). Six studies including 1,181 patients were included. Meta-analysis of all studies suggested that the combination therapy group had significant longer OS than TACE group [hazard ratio (HR) = 0.64, 95 % confidence interval (CI) = 0.43-0.97], but the pooled HR of randomized controlled trials (RCTs) failed to achieve statistical significance. For TTP, meta-analysis in both RCTs subgroup and retrospective studies subgroup suggested that combination therapy was superior to TACE group. The combination therapy was also associated with better response to treatment (risk ratio = 1.45, 95 % CI = 1.04-2.02) when both RCTs and retrospective studies were pooled. However, the sorafenib associated AEs were more frequent in the combination therapy group. In conclusion, the combination of TACE and sorafenib is likely to improve OS, TTP and response to treatment when compared with TACE monotherapy. The combination group is also associated with more sorafenib-related AEs.

An internet-based epidemiological investigation of the outbreak of H7N9 Avian influenza A in China since early 2013.

BACKGROUND: In early 2013, a new type of avian influenza, H7N9, emerged in China. It quickly became an issue of great public concern and a widely discussed topic on the Internet. A considerable volume of relevant information was made publicly available on the Internet through various sources. OBJECTIVE: This study aimed to describe the outbreak of H7N9 in China based on data openly available on the Internet and to validate our investigation by comparing our findings with a well-conducted conventional field epidemiologic study. METHODS: We searched publicly accessible Internet data on the H7N9 outbreak primarily from government and major mass media websites in China up to February 10, 2014. Two researchers independently extracted, compared, and confirmed the information of each confirmed H7N9 case using a self-designed data extraction form. We summarized the epidemiological and clinical characteristics of confirmed H7N9 cases and compared them with those from the field study. RESULTS: According to our data updated until February 10, 2014, 334 confirmed H7N9 cases were identified. The median age was 58 years and 67.0% (219/327) were males. Cases were reported in 15 regions in China. Five family clusters were found. Of the 16.8% (56/334) of the cases with relevant data, 69.6% (39/56) reported a history of exposure to animals. Of the 1751 persons with a close contact with a confirmed case, 0.6% (11/1751) of them developed respiratory symptoms during the 7-day surveillance period. In the 97.9% (327/334) of the cases with relevant data, 21.7% (71/327) died, 20.8% (68/327) were discharged from a hospital, and 57.5% (188/327) were of uncertain status. We compared our findings before February 10, 2014 and those before December 1, 2013 with those from the conventional field study, which had the latter cutoff date of ours in data collection. Our study showed most epidemiological and clinical characteristics were similar to those in the field study, except for case fatality (71/327, 21.7% for our data before February 10; 45/138, 32.6% for our data before December 1; 47/139, 33.8% for the field study), time from illness onset to first medical care (4 days, 3 days, and 1 day), and time from illness onset to death (16.5 days, 17 days, and 21 days). CONCLUSIONS: Findings from our Internet-based investigation were similar to those from the conventional field study in most epidemiological and clinical aspects of the outbreak. Importantly, publicly available Internet data are open to any interested researchers and can thus greatly facilitate the investigation and control of such outbreaks. With improved efforts for Internet data provision, Internet-based investigation has a great potential to become a quick, economical, novel approach to investigating sudden issues of great public concern that involve a relatively small number of cases like this H7N9 outbreak.