Table 3.

Summary of studies investigating neonic exposure and adverse human health effects (January 2005–December 2015).

Studies	Study population	Country of study	Results
Acute exposure
Elfman et al. 2009	19 conifer seedling planters: 17 men, 2 women	Sweden	No clear acute adverse effects reported after 1 week of exposure to IMI-treated seedlings.
Forrester 2014	1,142 exposure cases reported to a TX poison control network from 2000 to 2012	USA	Of the 1,142, 77% were identified as IMI alone or in combination with other neonics. Thirty-two neonic exposures (2.9%) resulted in “serious medical outcomes” including ocular irritation/pain, dermal irritation/pain, nausea, vomiting, oral irritation, red eye, erythema, rash, numbness, and dizziness. Chest pain (2 exposures; 0.2%), hypertension (0.2%), and tachycardia (0.2%) were the most frequently reported serious cardiovascular effects. No deaths reported.
Mohamed et al. 2009	68 hospital patients: 61 ingestion, 7 dermal exposures	Sri Lanka	Of the 56 patients with acute IMI poisoning (versus mixtures), only 2 developed severe symptoms. The majority had mild symptoms including nausea, vomiting, headache, dizziness, abdominal pain, and diarrhea. IMI exposure confirmed in 28 cases, with a median plasma concentration of 10.58 ng/L (IQR: 3.84–15.58 ng/L; range: 0.02–51.25 ng/L) on admission. Concentrations for 7 patients remained elevated for 10–15 hr post-ingestion, suggesting absorption and/or elimination may be saturable or prolonged at high doses. No deaths reported.
Phua et al. 2009	70 exposure cases reported to the Taiwan National Poison Center	China	Of the 57 cases of ingested neonics, the majority were of IMI (n = 53), followed by ACE (n = 2) and CLO (n = 2). The 10 most severe cases were from IMI alone. Two deaths reported (mortality rate 2.9%).
Chronic exposure
Carmichael et al. 2014	101 heart defect cases recruited from mothers who participated in a pop-based case control study in San Joaquin valley; 9 exposed/92 not exposed	USA	Significant association between residential proximity to agricultural use of IMI and tetralogy of Fallot (AOR 2.4, 95% CI: 1.1, 5.4).
Keil et al. 2014	407 children with ASD recruited from Childhood Autism Risks from Genetics and Environment (CHARGE) Study/206 controls	USA	Weak association between prenatal exposure to IMI and ASD (AOR 1.3, 95% CrI: 0.78, 2.2); OR increased to 2.0 (95% CrI: 1.0, 3.9) when limiting study population to those who self-identified as “frequent users” of flea and tick medicines containing IMI.
Marfo et al. 2015	35 symptomatic cases in Gunma prefecture/50 controls	Japan	Significant association between urinary DMAP and increased prevalence of memory loss, finger tremor, and other symptoms of unknown origin (OR 14, 95% CI: 3.5, 57).
Yang et al. 2014	73 anencephaly cases in San Joaquin valley; 6 exposed/67 not exposed	USA	Suggestive association between residential proximity to agricultural use of IMI and anencephaly (AOR 2.9, 95% CI: 1.0, 8.2).
Note: ACE, acetamiprid; AOR, adjusted odds ratio; ASD, autism spectrum disorder; CI, 95% confidence interval; CLO, clothianidin; CrI, credible interval; IMI, imidiacloprid.