Gaurav S. Ajmani

Evaluating nanoparticle breakthrough during drinking water treatment.

Background: Use of engineered nanoparticles (NPs) in consumer products is resulting in NPs in drinking water sources. Subsequent NP breakthrough into treated drinking water is a potential exposure route and human health threat. Objectives: In this study we investigated the breakthrough of common NPs—silver (Ag), titanium dioxide (TiO2), and zinc oxide (ZnO)—into finished drinking water following conventional and advanced treatment. Methods: NPs were spiked into five experimental waters: groundwater, surface water, synthetic freshwater, synthetic freshwater containing natural organic matter, and tertiary wastewater effluent. Bench-scale coagulation/flocculation/sedimentation simulated conventional treatment, and microfiltration (MF) and ultrafiltration (UF) simulated advanced treatment. We monitored breakthrough of NPs into treated water by turbidity removal and inductively coupled plasma–mass spectrometry (ICP-MS). Results: Conventional treatment resulted in 2–20%, 3–8%, and 48–99% of Ag, TiO2, and ZnO NPs, respectively, or their dissolved ions remaining in finished water. Breakthrough following MF was 1–45% for Ag, 0–44% for TiO2, and 36–83% for ZnO. With UF, NP breakthrough was 0–2%, 0–4%, and 2–96% for Ag, TiO2, and ZnO, respectively. Variability was dependent on NP stability, with less breakthrough of aggregated NPs compared with stable NPs and dissolved NP ions. Conclusions: Although a majority of aggregated or stable NPs were removed by simulated conventional and advanced treatment, NP metals were detectable in finished water. As environmental NP concentrations increase, we need to consider NPs as emerging drinking water contaminants and determine appropriate drinking water treatment processes to fully remove NPs in order to reduce their potential harmful health outcomes. Citation: Abbott Chalew TE, Ajmani GS, Huang H, Schwab KJ. 2013. Evaluating nanoparticle breakthrough during drinking water treatment. Environ Health Perspect 121:1161–1166; http://dx.doi.org/10.1289/ehp.1306574

Effects of Ambient Air Pollution Exposure on Olfaction: A Review.

Background: Olfactory dysfunction affects millions of people worldwide. This sensory impairment is associated with neurodegenerative disease and significantly decreased quality of life. Exposure to airborne pollutants has been implicated in olfactory decline, likely due to the anatomic susceptibility of the olfactory nerve to the environment. Historically, studies have focused on occupational exposures, but more recent studies have considered effects from exposure to ambient air pollutants. Objectives: To examine all relevant human data evaluating a link between ambient pollution exposure and olfaction and to review supporting animal data in order to examine potential mechanisms for pollution-associated olfactory loss. Methods: We identified and reviewed relevant articles from 1950 to 2015 using PubMed and Web of Science and focusing on human epidemiologic and pathophysiologic studies. Animal studies were included only to support pertinent data on humans. We reviewed findings from these studies evaluating a relationship between environmental pollutant exposure and olfactory function. Results: We identified and reviewed 17 articles, with 1 additional article added from a bibliography search, for a total of 18 human studies. There is evidence in human epidemiologic and pathologic studies that increased exposure to ambient air pollutants is associated with olfactory dysfunction. However, most studies have used proxies for pollution exposure in small samples of convenience. Human pathologic studies, with supporting animal work, have also shown that air pollution can contact the olfactory epithelium, translocate to the olfactory bulb, and migrate to the olfactory cortex. Pollutants can deposit at each location, causing direct damage and disruption of tissue morphology or inducing local inflammation and cellular stress responses. Conclusions: Ambient air pollution may impact human olfactory function. Additional studies are needed to examine air pollution–related olfactory impacts on the general population using measured pollution exposures and to link pollution exposure with olfactory dysfunction and related pathology. Citation: Ajmani GS, Suh HH, Pinto JM. 2016. Effects of ambient air pollution exposure on olfaction: a review. Environ Health Perspect 124:1683–1693; http://dx.doi.org/10.1289/EHP136

Aluminum-humic colloid formation during pre-coagulation for membrane water treatment: Mechanisms and impacts

Precoagulation has been widely used by low pressure membrane filtration (LPMF) plants to reduce membrane fouling and increase natural organic matter (NOM) removal. Formation of aluminum and aluminum-NOM moieties plays a fundamental role in this important water treatment process. This study comprehensively investigated the mechanisms of aluminum-NOM species formation during precoagulation and their impacts on LPMF performance. The results show that, at low alum doses, e.g. 0.5 mg and 1.0 mg Al L(-1), humic substances (HS) and Al species (amorphous Al(OH)3, or Al(OH)3(am)) reacted to form small Al(OH)3(am)-HS colloids. Increases in alum dose resulted in sequential transitions of the Al-HS moieties to larger particles and, eventually, precipitates. Compared to waters containing only naturally occurring organic colloids (OC) or HS, the coexistence of OC and HS facilitated the formation of Al-HS precipitates, thereby increasing the removal of HS by 7-15%, but the removal of OC was decreased by 3-20%. Interestingly, these transitions in Al-HS moieties did not affect membrane fouling. Both short-term and long-term filtration results demonstrate that OC, rather than the Al(OH)3(am)-HS colloids, primarily caused membrane fouling. These findings highlight the dynamics of particulate Al-NOM formation during precoagulation and its relationship with membrane fouling, which can be utilized to optimize the operation of integrated precoagulation-LPMF systems on full-scale installations.

Smoking and olfactory dysfunction: A systematic literature review and meta-analysis

A systematic review and meta‐analysis of the literature was undertaken, examining the association between tobacco smoking and olfactory function in humans, utilizing PubMed and Web of Science (1970–2015) as data sources.

Assessment of adjuvant therapy in resected head and neck cancer with high-risk features

OBJECTIVES Subgroup analysis from two randomized trials showed a survival benefit for adjuvant chemoradiation (CRT) over radiation alone (RT) in patients with extracapsular spread (ECS) of involved lymph nodes and/or positive margins (PM) in resected head and neck cancer (HNSCC). However, results were not analyzed separately for patients with ECS or PM and were not stratified by tumor subsite/HPV status. We therefore sought to determine whether adjuvant CRT is associated with a survival benefit, separately among patients with ECS or PM and stratified by subsite/HPV status. METHODS Using the National Cancer Database (NCDB), we identified 6948 patients diagnosed with HNSCC between 2010 and 13 who underwent surgical resection and had either ECS or PM. The impact of adjuvant therapy on OS from surgery was evaluated using Cox proportional hazards regression adjusting for clinical and demographic factors. RESULTS Adjuvant CRT was associated with a significant survival benefit over RT alone among patients with ECS (aHR 0.83, 95%CI 0.71-0.97) but not among those with PM (aHR 0.89, 95%CI 0.77-1.04). In patients with HPV-negative tumors, CRT was associated with a benefit over RT alone in the setting of ECS (aHR 0.83, 95%CI 0.70-0.98) but not PM (aHR 0.91, 95%CI 0.78-1.06). However, in patients with HPV-positive oropharynx tumors, CRT was not associated with a benefit over RT in ECS (aHR 0.94, 95%CI 0.47-1.88) but appeared beneficial in PM (aHR 0.54, 95%CI 0.32-0.90). CONCLUSIONS CRT appears beneficial over RT in ECS among patients with HPV-negative tumors, and beneficial in PM among patients with HPV-positive tumors.

Surgical quality of wedge resection affects overall survival in patients with early stage non–small cell lung cancer

Objectives: Very few studies have examined the quality of wedge resection in patients with non–small cell lung cancer. Using the National Cancer Database, we evaluated whether the quality of wedge resection affects overall survival in patients with early disease and how these outcomes compare with those of patients who receive stereotactic radiation. Methods: We identified 14,328 patients with cT1 to T2, N0, M0 disease treated with wedge resection (n = 10,032) or stereotactic radiation (n = 4296) from 2005 to 2013 and developed a subsample of propensity‐matched wedge and radiation patients. Wedge quality was grouped as high (negative margins, >5 nodes), average (negative margins, ≤5 nodes), and poor (positive margins). Overall survival was compared between patients who received wedge resection of different quality and those who received radiation, adjusting for demographic and clinical variables. Results: Among patients who underwent wedge resection, 94.6% had negative margins, 44.3% had 0 nodes examined, 17.1% had >5 examined, and 3.0% were nodally upstaged; 16.7% received a high‐quality wedge, which was associated with a lower risk of death compared with average‐quality resection (adjusted hazard ratio [aHR], 0.74; 95% confidence interval [CI], 0.67‐0.82). Compared with stereotactic radiation, wedge patients with negative margins had significantly reduced hazard of death (>5 nodes: aHR, 0.50; 95% CI, 0.43‐0.58; ≤5 nodes: aHR, 0.65; 95% CI, 0.60‐0.70). There was no significant survival difference between margin‐positive wedge and radiation. Conclusions: Lymph nodes examined and margins obtained are important quality metrics in wedge resection. A high‐quality wedge appears to confer a significant survival advantage over lower‐quality wedge and stereotactic radiation. A margin‐positive wedge appears to offer no benefit compared with radiation.

Racial disparities in the choice of definitive treatment for squamous cell carcinoma of the oral cavity

Definitive surgery is recommended for oral cavity squamous cell carcinoma (SCC). The purpose of this study was to present our assessment of the disparities in treatment selection for oral cavity SCC.

Association of Facility Volume With Positive Margin Rate in the Surgical Treatment of Head and Neck Cancer

Importance The achievement of complete tumor resection with tumor-free margins is one of the main principles of oncologic surgery for head and neck squamous cell carcinoma (HNSCC). The negative prognostic influence of a positive margin (PM) across all head and neck subsites has been well established. National guidelines recommend the use of adjuvant chemoradiation therapy (CRT) in the setting of PM. Objective To determine the incidence of PM in HNSCC across multiple subsites, as well as the factors associated with its occurrence. Design, Setting, and Participants This retrospective cohort study used the National Cancer Database to identify patients diagnosed with HNSCC between 2010 and 2014 and who underwent surgical resection (n = 28 840). Main Outcomes and Measures Predictors of PM rate and likelihood to receive adjuvant CRT. Results Among the 28 840 patients included in this study, 19 727 (68.4 %) were men, and the average age was 62.4 years (range, 40 to ≥90 years). In univariable analysis, a lower PM rate was associated with higher facility volume (26.3% for the lowest volume quartile, 16.5% for the middle 2 quartiles, and 10.8% for the highest volume quartile) and treatment at academic vs nonacademic facilities (14.0% vs 22.7%). In multivariate analysis, those treated at higher-volume facilities remained significantly less likely to have PM (adjusted odds ratio, 0.85; 95% CI, 0.83-0.88). The trend of decreasing PM rate with increasing facility volume was observed in both academic (aOR, 0.88 per 10-case volume increase [95% CI, 0.85-0.91]) and nonacademic (aOR, 0.73 per 10-case volume increase [95% CI, 0.68-0.80]) facilities. There was no association between facility volume and patient likelihood of receiving adjuvant CRT in the setting of PM (compared with CCPs: aOR, 0.98 per 10-case volume increase [95% CI, 0.84-1.14] for CCCPs; and aOR, 1.24 [95% CI, 0.99-1.55] for INCPs). Conclusions and Relevance These findings suggest that high-volume facilities are associated with lower rates of PM in the surgical treatment of HNSCC in both academic and nonacademic settings. Facility volume for head and neck oncologic surgeries may be considered a benchmark for quality of care.

Association of a Proactive Swallowing Rehabilitation Program With Feeding Tube Placement in Patients Treated for Pharyngeal Cancer

Importance A proactive speech and language pathology (SLP) program is an important component of the multidisciplinary care of patients with head and neck squamous cell carcinoma (HNSCC). Swallowing rehabilitation can reduce the rate of feeding tube placement, thereby significantly improving quality of life. Objective To evaluate the initiation of a proactive SLP rehabilitation program at a single institution and its association with rates of feeding tube placement and dietary intake in patients with HNSCC. Design, Setting, and Participants Cohort study at a tertiary care and referral center for patients with HNSCC serving the northern Chicago region. Patients were treated for squamous cell carcinomas of the hypopharynx, oropharynx, and nasopharynx from 2004 to 2015 with radiation or chemoradiation therapy in the definitive or adjuvant setting. Patients who received less than 5000 cGy radiation or underwent reirradiation were excluded. Interventions A proactive SLP program for patients with HNSCC was initiated in 2011. Study cohorts were divided into 2 groups: 2004 through 2010 and 2011 through 2015. Main Outcomes and Measures Primary outcome variables were SLP referral placement and timing of the referral. Secondary outcomes were feeding tube placement and ability to tolerate any oral intake. Results A total of 254 patients met inclusion criteria (135 before and 119 after implementation of SLP program; median age, 60 years [range, 14-94 years]; 77% male). With the initiation of a proactive SLP program, pretreatment evaluations increased from 29 (21.5%) to 70 (58.8%; risk ratio [RR], 2.74; 95% CI, 1.92-3.91), and rate of referral overall at any time increased from 60.0% to 79.8% (RR, 1.33; 95% CI, 1.13-1.57). Feeding tube placement rates decreased from 45.9% (n = 62) to 29.4% (n = 35; RR, 0.64; 95% CI, 0.46-0.89). Among patients receiving a swallow evaluation, feeding tube requirements were less frequent for those receiving a pretreatment evaluation (31 of 99 [31%]) than for those referred during (11 of 18 [61%]) or after (38 of 59 [64%]) treatment. The rate of tolerating any oral intake at the end of treatment improved from 71.1% (n = 96) in the preimplementation period to 82.4% (n = 98; RR, 1.16; 95% CI, 1.01-1.33). Conclusions and Relevance A proactive SLP program can be successfully established as part of the multidisciplinary care of patients with HNSCC and improve patient quality of life.

Allergy and asthma medication use in home‐dwelling U.S. older adults

Little is known about the use of allergy and asthma medications in older adults. This study aimed to assess the prevalence of use of these medications in older adults and evaluate predictors of their use.