Environmental factors associated with autism spectrum disorder: a scoping review for the years 2003-2013

INTRODUCTION

The number of children diagnosed with autism spectrum disorder (ASD) has been rapidly rising in the past decade. The etiology of this disorder, however, is largely unknown, although the environmental relative to the genetic contribution is substantial. We conducted a scoping review to comprehensively assess the current state of knowledge of the environmental factors present from preconception to early life associated with ASD, and to identify research gaps.

METHODS

We searched electronic databases MEDLINE, PsycINFO and ERIC for articles on potential risk factors or protective factors from the physical and social environments associated with ASD and its subclassifications published between 1 January, 2003, and 12 July, 2013. We categorized articles into broad themes: chemical, physiological, nutritional and social factors, based on environmental exposure.

RESULTS

We identified over 50 000 publications, but after ineligible studies were screened out, 315 articles remained. Most of these studies examined physiological factors, followed closely by chemical factors, and to a much lesser extent, nutritional and social factors, associated with ASD. Despite a vast literature and many heterogeneous studies, several risk factors emerged consistently: chemical factors such as traffic-related air pollutants; physiological factors including advanced parental age, preterm birth, low birth weight, hyperbilirubinemia and clustering of pregnancy complications; and maternal immigrant status. Despite extensive research on vaccines, findings overwhelmingly demonstrate no support for an association with ASD.

CONCLUSION

The lack of consistency, temporality and specificity of associations between environmental factors and ASD remains the largest barrier to establishing causal relationships. More robust research is required to resolve inconsistencies in the literature. Future research should explore underlying mechanisms of associations between the risk factors that we identified and ASD.

Extensive Cervicomediastinal Emphysema from Mastoid Injury

Traumatic cervicomediastinal emphysema resulting from isolated head trauma is a rare occurrence. Herein, we describe a patient who sustained a closed mastoid injury after being struck with a batted baseball, resulting in acute extensive cervicomediastinal emphysema. Upon further assessment, the patient's aerodigestive tract was determined to have remained intact and unaffected by the injury. The source of soft-tissue air originated from the fractured mastoid. This case demonstrates the protective properties of a well-pneumatized mastoid. Furthermore, we elucidate the pathway by which the mastoid air entered and spread into the surrounding soft tissues of the neck and into the chest.

Safety and efficacy of aflibercept in combination with fluorouracil, leucovorin and irinotecan in the treatment of Asian patients with metastatic colorectal cancer

AIM

To evaluate the safety and efficacy of the combination therapy of fluorouracil, leucovorin and irinotecan (FOLFIRI) and aflibercept in Asian patients with metastatic colorectal cancer (mCRC), who had progressed after oxaliplatin-based chemotherapy.

METHODS

This is a retrospective analysis of 19 mCRC patients who received FOLFIRI and aflibercept (4 mg/kg intravenously) every 2 weeks via a Named Patient Program (supported by Sanofi Aventis) in Singapore. Treatment was administered until disease progression or unacceptable toxicities. Kaplan-Meier method was used to estimate progression-free survival (PFS) and overall survival (OS). Efficacy and toxicities were summarized using descriptive statistics. Statistical analysis was performed using STATA 12.0 software.

RESULTS

The majority (84%) of the patients were of chinese ethnicity. The median age was 59 years, with 63.2% of the patients having an Eastern Cooperative Oncology Group status of 1. Four patients (21.1%) achieved partial response and 8 patients (42.1%) achieved stable disease. After a median follow-up of 9.6 months [95% confidence interval (CI), 2.2-13.1 months], the median OS was 11.6 months (95% CI, 6.1 to not-estimable), and median PFS was 4.1 months (95% CI, 2.2-5.9). Majority of the toxicities were grade 1-2, and include leucopenia (84.2%), anemia (73.7%), liver enzyme elevation (68.4%) and fatigue (68.4%). The most frequently reported grade 3 toxicities were neutropenia and neutropenic complications (both 15.8%). All adverse events resolved with supportive management.

CONCLUSION

The clinical benefit and safety profile of the combination of FOLFIRI/aflibercept in Asian patients with mCRC are consistent with that of Western population. FOLFIRI/aflibercept may be an appropriate therapeutic option in Asian patients with mCRC previously treated with an oxaliplatin-based regimen.

Phase II study of trastuzumab in combination with S-1 and cisplatin in the first-line treatment of human epidermal growth factor receptor HER2-positive advanced gastric cancer

PURPOSE

The use of trastuzumab, a monoclonal antibody targeting the HER2 protein, in combination with 5-fluorouracil/platinum-based chemotherapy improves survival in patients with HER2-positive advanced gastric cancer. In addition, TS-one (S-1)/platinum is also used as a standard of care in Asian countries. However, little is known about the combination of S-1/cisplatin chemotherapy and trastuzumab in patients with HER2-positive advanced gastric/gastroesophageal junction (GEJ) cancer.

METHODS

We conducted a single-arm, two-stage, open-label, multicenter phase II study. Trastuzumab was administered intravenously on day 1 of the first cycle at 8 mg/kg and 6 mg/kg on day 1 of subsequent cycles. Cisplatin was administered intravenously at 60 mg/m(2) on day 1 of each cycle after trastuzumab. S-1 was administered orally [based on body surface area (BSA)] twice a day for 14 days in a 3-weekly cycle. Patients with BSA of <1.25 received a total of 80 mg of S-1, those with BSA ≥1.5 received 120 mg, and the remaining received 100 mg daily in two divided doses.

RESULTS

All evaluable patients experienced tumor reduction during the trial. The primary end point (overall survival rate) was 59.3 %, with a clinical benefit rate of 66.7 %. Median progression-free survival was 7.4 months; 62.6 % patients were free from disease progression at 6 months. Median overall survival was 14.6 months, and the median time to treatment failure was 6.0 months.

CONCLUSION

The combination of trastuzumab with S-1 and cisplatin demonstrated good activity, was generally well tolerated, and is a feasible treatment option in the first-line treatment of HER2-positive advanced gastric/GEJ cancers.